Laminated polyester film

Abstract

A laminated polyester film having a polyester film and a resin layer formed using a resin composition, the resin layer being formed on at least one side of the polyester film, the laminated polyester film satisfying all of the following (1) to (3). (1) The resin layer has a concavo-convex structure. (2) The resin composition contains the following compounds (A) and (B). (A) a low-polarity compound, (B) one or more selected from the group consisting of a binder resin and a crosslinking agent. (3) A support length ratio (Rmr(80)) of a roughness curve at 80% of a cut level of the surface of the resin layer when measured by a scanning probe microscope is 76% or less. A laminated polyester film can be provided, which can form a fine concavo-convex structure even if it is a film, and has excellent handling properties when the film is wound into a roll, etc.

Description

Technical Field

[0001] This invention relates to laminated polyester films. Background Technology

[0002] Polyester films, represented by polyethylene terephthalate (PET) film and polyethylene naphthalate (PAN) film, possess excellent mechanical properties, dimensional stability, flatness, heat resistance, chemical resistance, and optical properties, and offer excellent cost performance. Therefore, they are used in a variety of applications.

[0003] In addition, due to the smoothness of its surface, polyester film can be used in a variety of applications, such as release films for forming green sheets of multilayer ceramic capacitors, substrates for release of interlayer insulating resins, and substrates for dry film resists.

[0004] Polyester films for sheet forming, which are characterized by excellent surface smoothness and are used in the above-mentioned applications, need to be wrinkle-free and have a good roll appearance when rolled into a roll.

[0005] However, if the surface smoothness is improved, the slipability will decrease, and the air discharge when the coil is unwound will be worse, resulting in coil misalignment, adhesion, and reduced operability.

[0006] In recent years, in particular, with the improvement of productivity, there is a tendency to further promote the production of longer strips of polyester film, requiring a higher level of roll appearance quality.

[0007] Therefore, in order to ensure operability, the non-smooth side (back side) is sometimes designed to be rougher than the smooth side by incorporating particles (e.g., Patent Document 1).

[0008] In addition, Patent Document 2 discloses a back resin layer having a surface with a recess formed by an island structure and an arithmetic mean roughness (Ra) of 10 nm to 80 nm as the back side.

[0009] In addition, patent documents 3 and 4 disclose laminated thin films having uneven layers based on phase separation.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: Japanese Patent Application Publication No. 2015-33811

[0013] Patent Document 2: Japanese Patent Application Publication No. 2013-60555

[0014] Patent Document 3: Japanese Patent Application Publication No. 2013-10323

[0015] Patent Document 4: Japanese Patent Application Publication No. 2021-24177 Summary of the Invention

[0016] The problem the invention aims to solve

[0017] However, in the conventional method for manufacturing particulate compound films disclosed in Patent Document 1, it is difficult to control the formation of unevenness and to form a fine uneven structure.

[0018] In addition, the films disclosed in Patent Documents 2 to 4 have problems such as having a textured structure that is difficult to describe as fine, or having a thicker layer with textures.

[0019] More specifically, when the roll is not a finely textured structure, it is easy to produce wrinkles, and sometimes the appearance of the roll is damaged.

[0020] In addition, when the layer with unevenness is thick, the flatness is sometimes damaged due to curling caused by curing shrinkage, which sometimes makes it unsuitable for the elongation of polyester film.

[0021] Therefore, the present invention was made in view of the above-mentioned actual situation, and the problem it solves is to provide a laminated polyester film that, even as a film, can form a fine uneven structure and has excellent processability, such as when the film is rolled into a roll.

[0022] Solution for solving the problem

[0023] The inventors conducted in-depth research and found that the above-mentioned problems can be solved by having the following configuration.

[0024] The present invention has the following aspects.

[0025] [1] A laminated polyester film comprising a polyester film and a resin layer formed of a resin composition, the resin layer being formed on at least one side of the aforementioned polyester film, the laminated polyester film satisfying all of the following conditions (1) to (3).

[0026] (1) The aforementioned resin layer has an uneven structure.

[0027] (2) The aforementioned resin composition comprises the following compounds (A) and (B).

[0028] (A) Low polar compounds

[0029] (B) Selected from one or more of the group consisting of adhesive resins and crosslinking agents

[0030] (3) The bearing length ratio (Rmr(80)) of the roughness curve at the cut level of 80% of the aforementioned resin layer surface when measured by scanning probe microscope is less than 76%.

[0031] [2] According to the laminated polyester film described above [1], the bearing length ratio (Rmr(50)) of the roughness curve at the cut level of 50% of the surface of the aforementioned resin layer when measured by scanning probe microscope is 60% or less.

[0032] [3] According to the laminated polyester film described in [1] or [2] above, the arithmetic mean roughness (Ra) of the surface of the aforementioned resin layer when measured by a scanning probe microscope is 20 nm or more.

[0033] [4] The laminated polyester film according to any one of [1] to [3] above, wherein the ten-point average roughness (Rzjis) of the surface of the aforementioned resin layer when measured by a scanning probe microscope is 70 nm or more.

[0034] [5] The laminated polyester film according to any one of [1] to [4] above has an air leakage index of less than 130,000 seconds.

[0035] [6] The laminated polyester film according to any one of [1] to [5] above, wherein the aforementioned low polar compound comprises one or more compounds selected from the group consisting of waxes and compounds containing long-chain alkyl groups.

[0036] [7] The laminated polyester film according to any one of [1] to [6] above, wherein the aforementioned adhesive resin comprises one or more selected from the group consisting of (meth)acrylic resin, polyvinyl alcohol and ionically conductive polymeric compounds.

[0037] [8] The laminated polyester film according to any one of [1] to [7] above, wherein the aforementioned crosslinking agent comprises one or more selected from the group consisting of melamine compounds and oxazoline compounds.

[0038] [9] The laminated polyester film according to any one of [1] to [8] above, wherein the aforementioned resin composition contains a crosslinking catalyst as compound (C).

[0039]

[10] The laminated polyester film according to any one of [1] to [9] above, wherein the aforementioned resin composition contains microparticles as compound (D).

[0040]

[11] The laminated polyester film according to any one of [1] to

[10] above is used as a support for the ceramic green sheet in the manufacturing process of the laminated ceramic capacitor.

[0041] The effects of the invention

[0042] According to the present invention, a laminated polyester film is provided, which, even as a film, can form a fine uneven structure and has excellent processability, such as when the film is rolled into a roll.

[0043] Furthermore, the laminated polyester film of the present invention has the following advantages when used for sheet forming, for example, because the surface of the resin layer has a fine uneven structure: it also exhibits good rollability when the extremely smooth film is rolled into a roll and is not prone to wrinkles.

[0044] Furthermore, since the laminated polyester film of the present invention can make the resin layer a film, it can also cope with the elongation of the polyester film, which can help improve productivity by reducing the frequency of product roll switching during processing. Attached Figure Description

[0045] Figure 1 Images of the resin layer of Example 1-1 observed using a scanning probe microscope. Detailed Implementation

[0046] Next, an example of an embodiment of the present invention will be described. However, the present invention is not limited to the embodiments described below.

[0047] In this specification, when the term "(meth)acrylic" is used, "(meth)acrylic" refers to one or both of "acrylic" and "methacrylic". Similarly, "(meth)acrylic" refers to one or both of "acrylic acid" and "methacrylic acid", "(meth)acrylate" refers to one or both of "acrylate" and "methacrylate", and "(meth)acryloyl" refers to one or both of "acryloyl" and "methacryloyl". All other aspects are the same as described above.

[0048] <<<Laminated Polyester Film>>>

[0049] The laminated polyester film of the present invention (hereinafter also referred to as "this laminated polyester film") comprises a polyester film (hereinafter also referred to as "this polyester film") and a resin layer (hereinafter also referred to as "this resin layer") formed of a resin composition, said resin layer being formed on at least one side of the polyester film.

[0050] The laminated structure of this laminated polyester film can be a structure in which a resin layer is formed on one side of the polyester film and the other side directly becomes the surface of the polyester film, or it can be a structure in which other layers are formed on the other side.

[0051] Alternatively, it can be formed by forming resin layers on both sides of the polyester film.

[0052] Furthermore, a resin layer can be formed directly on the polyester film, or other layers can be provided between the polyester film and the resin layer.

[0053] <<Polyester Film>>

[0054] This polyester film serves as the substrate for the laminated polyester film. This polyester film can be a single-layer structure or a multi-layer structure. When the polyester film is a multi-layer structure, it can be a 2-layer structure, a 3-layer structure, etc., and can also be 4 layers or more, as long as it does not depart from the spirit of the invention; the number of layers is not particularly limited.

[0055] It should be noted that when the polyester film has a multilayer structure with two or more layers, two types of three-layer structures or three types of three-layer structures are particularly preferred. In the case of a multilayer structure, it is also preferable to have a structure in which surface layers are provided on both sides of the intermediate layer.

[0056] Especially when utilizing the smoothness of this laminated polyester film, it is preferable that at least one side of the polyester film has excellent smoothness. Examples of methods for this design include: making the polyester film a single layer, two types of three-layer structures, and three types of three-layer structures, and designing two sides of the polyester film to have excellent smoothness; and making the polyester film three types of three-layer structures, designing one side of the polyester film to have excellent smoothness, and designing the other side to have a different roughness.

[0057] Furthermore, this polyester film can be a non-stretched film (sheet) or a stretched film. Preferably, it is a stretched film stretched along a uniaxial or biaxial direction. Especially in terms of the balance of mechanical properties and excellent planarity, a biaxially stretched film is preferred.

[0058] Polyester

[0059] The polyester used as the raw material for this polyester film refers to a polymer compound having ester bonds continuously in its main chain, and can be either a homopolymer polyester or a copolymer polyester. Specifically, polyesters obtained by polycondensation reaction of a dicarboxylic acid component and a diol component can be cited as examples. In addition, it is preferable to use a polyester containing more than 50 mol% of aromatic dicarboxylic acid or aliphatic dicarboxylic acid when the dicarboxylic acid component is set to 100 mol%.

[0060] Examples of dicarboxylic acid components mentioned above include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, and 4,4'-diphenyl sulfone dicarboxylic acid, as well as aliphatic dicarboxylic acids such as adipic acid, octanoic acid, sebacic acid, dimer acid, dodecanoic acid, cyclohexanedicarboxylic acid, and their ester derivatives.

[0061] Examples of the aforementioned diol components include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, 1,4-hexanediethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis(4-hydroxyethoxyphenyl)propane, isosorbide diester, and spirodiol.

[0062] When the aforementioned polyester is a homopolymer polyester, it is preferable to obtain a polyester obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic diol. Examples of preferred aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalenedicarboxylic acid, while examples of preferred aliphatic diols include ethylene glycol, diethylene glycol, and 1,4-cyclohexanediethanol. Representative examples of homopolymer polyesters include polyethylene terephthalate (PET) and polyethylene 2,6-naphthalenedicarboxylic acid (PEN), with polyethylene terephthalate being preferred.

[0063] On the other hand, the copolyester is preferably a condensation polymer of a dicarboxylic acid component and an aliphatic diol. As the dicarboxylic acid component, one or more of the following are preferred: isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and hydroxycarboxylic acids (e.g., p-hydroxybenzoic acid). As the aliphatic diol, one or more of the following are preferred: ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanediol, and neopentyl glycol. More preferably, the copolyester contains terephthalic acid as the dicarboxylic acid component and ethylene glycol as the aliphatic diol.

[0064] When the aforementioned polyester is a copolyester, it is preferably a copolymer containing 30 mol% or less of a third component. The third component refers to the components constituting the polyester other than the compound that is the main component of the dicarboxylic acid component (i.e., the component with the highest content) and the compound that is the main component of the glycol component. For example, in the copolyethylene terephthalate, it is the component other than terephthalic acid and ethylene glycol.

[0065] Furthermore, the copolyester may also contain structural units derived from difunctional compounds other than dicarboxylic acids and aliphatic diols. The percentage of structural units derived from difunctional compounds other than dicarboxylic acids and aliphatic diols is preferably 20 mol% or less, more preferably 10 mol% or less, relative to the total molar number of all structural units constituting the polyester. Examples of difunctional compounds include various hydroxycarboxylic acids and aromatic diols.

[0066] The content of terephthalic acid in all dicarboxylic acid components constituting this polyester film is preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more.

[0067] Furthermore, the content of ethylene glycol in all the glycol components constituting this polyester film is preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more.

[0068] It should be noted that the upper limit for the content of terephthalic acid and ethylene glycol is 100 mol%.

[0069] In addition, the aforementioned polyester can be recycled polyester or polyester derived from biomass.

[0070] <Polycondensation catalyst>

[0071] There are no particular limitations on the polycondensation catalyst used to induce the polycondensation of the aforementioned polyester; conventionally known compounds can be used, such as titanium compounds, germanium compounds, antimony compounds, manganese compounds, aluminum compounds, magnesium compounds, and calcium compounds.

[0072] Among these, at least one of titanium compounds and antimony compounds is preferred, with polyesters obtained using titanium compounds being particularly preferred.

[0073] Therefore, this polyester film preferably contains at least one of a titanium compound and an antimony compound, more preferably a titanium compound.

[0074] By using the aforementioned titanium compound, the amount of antimony compound used can be reduced, thus reducing the risk of new protrusions caused by the precipitation of antimony compound on the film surface and maintaining a high degree of surface smoothness.

[0075] Therefore, as a particularly preferred approach, it can be listed that, in the case where the polyester film has a multilayer structure, the polyester constituting at least one surface layer uses a titanium compound.

[0076] The titanium content of the aforementioned surface layer derived from titanium compounds is preferably 3 ppm or more and 40 ppm or less by mass, more preferably 4 ppm or more and 35 ppm or less. Furthermore, if the surface layer contains at least one of an antimony compound and a titanium compound, the antimony content in the surface layer is preferably 0 ppm or more and 100 ppm or less. Within this range, manufacturing efficiency is not reduced, and foreign matter originating from the catalyst is minimized.

[0077] It should be noted that, from the perspective of productivity and cost, it is also preferable that the polyester constituting the layers other than the surface layer does not use titanium compounds.

[0078] Based on the above, by including a titanium compound in this polyester film, a polyester film with excellent smoothness can be produced. Furthermore, if a laminated polyester film containing this resin layer is produced, this laminated polyester film can be appropriately used for sheet forming, etc.

[0079] Intrinsic viscosity

[0080] The intrinsic viscosity (IV) of the polyester constituting this polyester film is preferably 0.50 dL / g or higher, more preferably 0.55 dL / g or higher, and even more preferably 0.60 dL / g or higher. Within this range, there are advantages such as high particle dispersion due to increased shear stress during mixing. Furthermore, the intrinsic viscosity (IV) of this polyester is, for example, 1.00 dL / g or lower.

[0081] It should be noted that "the intrinsic viscosity (IV) of the polyester constituting this polyester film" refers to the intrinsic viscosity (IV) of the mixed polyesters when two or more polyesters with different intrinsic viscosities (IV) are used.

[0082] When the polyester film has a multilayer structure, the intrinsic viscosity (IV) of the polyester constituting the surface layer is preferably within the range described above.

[0083] <particles>

[0084] This polyester film may also contain particles. By including particles in the polyester film, it is given a slip-resistant property, and damage during each process is prevented, resulting in good processability.

[0085] Regarding the types of particles contained in this polyester film, there are no particular limitations as long as the particles can impart slipperiness. Specific examples include inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, alumina, and titanium dioxide; and organic particles such as cross-linked polymers such as cross-linked silicone resin particles, cross-linked acrylic resin particles, cross-linked styrene-acrylic resin particles, and cross-linked polyester particles, as well as calcium oxalate and ion exchange resins. Among these, organic particles, silica, and alumina are preferred. From the viewpoint of hardening the layer to prevent damage to the film surface and maintaining smoothness, alumina is preferred.

[0086] Furthermore, precipitated particles formed by precipitating and micro-dispersing a portion of metal compounds such as catalysts during the polyester manufacturing process can also be used.

[0087] There are no particular restrictions on the shape of the particles used; any shape, such as spherical, blocky, rod-shaped, or flat, can be used.

[0088] Furthermore, there are no particular restrictions on its hardness, specific gravity, color, etc. Two or more of these particles can be used in combination as needed.

[0089] Furthermore, the average particle size of the particles used is typically 5 μm or less, preferably 0.01 to 3 μm, more preferably 0.02 to 1 μm, and even more preferably in the range of 0.03 to 0.5 μm. If the particle size is 5 μm or less, the surface roughness of the film will not become excessively rough, preventing adverse effects during subsequent processes such as forming the resin layer and various surface functional layers other than the resin layer. Additionally, if the average particle size is within the above range, haze is suppressed to a lower level, easily ensuring the overall transparency of the laminated polyester film.

[0090] It should be noted that the average particle size can be determined by observing the diameter of more than 10 particles using a scanning electron microscope (SEM) and using this average as the value. In the case of non-spherical particles, the average of the longest and shortest diameters can be measured as the diameter of each particle.

[0091] When the polyester film contains particles, it is preferable to provide a surface layer and an intermediate layer, with the surface layer containing particles. Alternatively, when different designs are made for the surface and back sides using three different three-layer structures, particles may be contained only in at least one surface layer.

[0092] The particle content also depends on the average particle size, but in layers containing particles, it is typically 5000 ppm or less by mass, preferably 3000 ppm or less, and more preferably 1000 ppm or less. In the absence of particles, or when the particle content is low, sufficient slip properties cannot be provided; although the transparency of the polyester film increases, sometimes the slip properties become insufficient. Therefore, it is necessary to improve slip properties, etc., by laminating the resin layer described later. Furthermore, if it is 5000 ppm or less, the transparency of the polyester film can be sufficiently ensured. In addition, in layers containing particles, the particle content is not particularly limited, for example, 50 ppm or more, preferably 100 ppm or more.

[0093] The resin layer described later can be disposed on a particulate layer of the polyester film or on a substantially partless layer. Furthermore, in the polyester film, the side opposite to the side where the resin layer is disposed (the opposite side) can be a substantially partless layer or a particulate layer. In this invention, even if both the side where the resin layer is disposed and the opposite side are substantially partless layers, the resin layer with its uneven structure described later can still provide good rollability. Furthermore, by making one or both of the side where the resin layer is disposed and the opposite side a particulate layer, rollability is easily improved.

[0094] When imparting excellent smoothness to at least one surface of the polyester film, the surface layer on the smooth side may contain particles or may be substantially free of particles, but in the case of producing an extremely smooth film, it is preferable to be substantially free of particles.

[0095] It should be noted that "substantially free of" means unintentionally containing particles. Specifically, it means that the particle content (particle concentration) is less than 50 ppm by mass, more preferably less than 40 ppm, and even more preferably less than 30 ppm.

[0096] In this case, by laminating the resin layer on the surface layer on the smooth side and / or on the surface layer on the opposite side of the smooth side, the operability when winding the film into a roll can be improved. From the viewpoint of maintaining the smoothness of the film and improving operability, it is preferable to make at least one side smooth and to laminate the resin layer on the opposite side.

[0097] There are no particular limitations on the method for adding particles to this polyester film, and conventionally known methods can be used. For example, if it is a multilayer polyester film, the particles can be added at any stage of manufacturing the polyester that makes up each layer, but it is preferable to add them after the esterification or transesterification reaction is completed.

[0098] <Other>

[0099] To suppress the precipitation of oligomer components, polyester with a low oligomer content can be used as a raw material to manufacture films. Various known methods can be used to manufacture polyester with a low oligomer content; for example, methods involving solid-state polymerization after polyester manufacturing can be listed.

[0100] Alternatively, the polyester film can be configured with three or more layers, and the surface layer of the polyester film can be a layer made of polyester raw material with a low content of oligomer components, thereby suppressing the amount of oligomer components released.

[0101] Alternatively, polyester can be obtained by further increasing the reaction temperature and performing melt polycondensation under reduced pressure after esterification or transesterification.

[0102] It should be noted that, in addition to the particles mentioned above, conventionally known UV absorbers, antioxidants, antistatic agents, heat stabilizers, lubricants, dyes, pigments, etc., may be added to this polyester film as needed.

[0103] The thickness of the polyester film is not particularly limited as long as it is within the range that can be used as a film for film making. From the viewpoints of mechanical strength, operability and productivity, it is preferably 1 μm or more, more preferably 10 μm or more, further preferably 19 μm or more, particularly preferably 25 μm or more, and preferably 200 μm or less, more preferably 125 μm or less, further preferably 80 μm or less, particularly preferably 50 μm or less.

[0104] <Manufacturing Method of Polyester Film>

[0105] Next, a specific example of manufacturing this polyester film will be described, but it is not limited to any of the following manufacturing examples. For example, in the case of manufacturing a biaxially stretched film, the following method is preferred: the dried granules of the previously described polyester raw material are extruded from a die into molten sheets using a melt extrusion apparatus such as an extruder, and then cooled and solidified using a cooling roller such as a rotary cooling cylinder to obtain an unstretched sheet. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the cooling roller, and it is preferable to use an electrostatic application method and / or a liquid coating method.

[0106] Next, the obtained unstretched sheet is stretched along a biaxial direction. In this case, firstly, the unstretched sheet is stretched in one direction using a stretching machine of the roller or tenter type. The stretching temperature is usually 70 to 120°C, preferably 80 to 110°C, and the stretching ratio is usually 2.5 to 7.0 times, preferably 3.0 to 6.0 times.

[0107] Next, stretching is performed in a direction orthogonal to the stretching direction of the first stage. At this time, the stretching temperature is usually 70 to 170°C, and the stretching ratio is usually 3.0 to 7.0 times, preferably 3.5 to 6.0 times.

[0108] Then, heat treatment is continued at a temperature typically between 180 and 270°C, under tension or with a relaxation of up to 30%, to obtain a biaxially stretched film. This heat treatment is also known as the heat setting process. Heat treatment can also be performed in two or more stages at different temperatures.

[0109] Alternatively, cooling can be performed in a cooling zone after heat treatment. The cooling temperature is preferably higher than the glass transition temperature (Tg) of the polyester constituting the film, and more specifically, preferably in the range of 100–160°C. This cooling can also be performed through two or more steps at different temperatures.

[0110] In the above-described stretching process, a method of performing unidirectional stretching in two or more stages can also be used. In this case, it is preferable to perform the stretching in both directions such that the final stretching ratios are within the ranges described above.

[0111] Alternatively, the polyester film can also be manufactured using a simultaneous biaxial stretching method. The simultaneous biaxial stretching method involves simultaneously stretching and orienting the aforementioned unstretched sheet in both the mechanical direction (longitudinal) and the width direction (transverse) at a temperature controlled temperature of typically 70–120°C, preferably 80–110°C. The stretching ratio, in terms of area ratio, is preferably 4–50 times, more preferably 7–35 times, and even more preferably 10–25 times.

[0112] Then, heat treatment is continued at a temperature typically between 170 and 250°C, under tension or with a relaxation of up to 30%, to obtain a stretched and oriented film. Regarding the biaxial stretching apparatus employing the above stretching method, conventionally known stretching methods such as screw-type, scaling-type, and linear drive-type stretching methods can be used.

[0113] <<Resin Layer>>

[0114] This laminated polyester film has a resin layer formed of a resin composition on at least one side of the polyester film. The resin layer may be a cured resin layer.

[0115] As described above, this resin layer is formed from a resin composition (hereinafter also referred to as "this composition") and has an uneven structure.

[0116] <Concave-convex structure>

[0117] The uneven structure of this resin layer is a fine shape formed by phase separation. The unevenness based on phase separation is achieved when components containing resins with different compatibility undergo phase separation during processes such as coating, stretching, drying, curing, and heat treatment, thereby forming an uneven structure on the surface. More specifically, it is obtained by forming concave or convex portions through phase separation, thereby creating an uneven structure on the surface.

[0118] It should be noted that its structure can be confirmed using various surface analysis methods, such as atomic force microscopy (scanning probe microscopy).

[0119] In this invention, "resin" refers to the main component involved in the formation of the coating. More specifically, compounds (A) and (B), described later, can be cited as examples of "resin".

[0120] <Resin Composition>

[0121] This composition comprises the following compounds (A) and (B).

[0122] (A) Low polar compounds

[0123] (B) One or more selected from the group consisting of adhesive resins and crosslinking agents

[0124] The total content of compounds (A) and (B) in this composition, based on non-volatile components, is preferably 50% by mass or more. More preferably, it is 60% by mass or more, and even more preferably 65% ​​by mass or more. If the total content is within the range described above, the effect based on phase separation can be fully utilized, and the desired fine textured structure can be easily obtained. It should be noted that there is no particular upper limit to the total content of compounds (A) and (B), as long as it is 100% by mass or less.

[0125] (((Compound(A))))

[0126] This composition contains (A) a low-polarity compound (compound (A)). There are no particular limitations on the aforementioned low-polarity compound (A), and conventionally known compounds can be used; specifically, conventionally known compounds used as mold release agents can be used. Examples of compound (A) include waxes, compounds containing long-chain alkyl groups, fluorinated compounds, and organosilicon compounds. Preferably, it is at least one of waxes and compounds containing long-chain alkyl groups, more preferably waxes. In this composition, compound (A) can be used alone or in combination of two or more.

[0127] As described above, the uneven structure of this resin layer is formed by phase separation of resins with different compatibility. By including compound (A) in this composition, the water-repellent and / or oil-repellent effects of the low-polarity compound (A) can be utilized to effectively exhibit a fine uneven structure. The mechanism by which the uneven structure is formed using water-repellent and / or oil-repellent effects is not yet certain, but it is speculated that it utilizes water-repellent and / or oil-repellent properties to repel other resins, and uses the repelled resins to form protrusions, thereby more effectively forming fine unevenness.

[0128] (wax)

[0129] Examples of waxes mentioned above include natural waxes, synthetic waxes, and modified waxes.

[0130] Natural waxes refer to plant-based waxes, animal-based waxes, mineral-based waxes, and petroleum waxes.

[0131] Plant-based waxes include candelilla wax, carnauba wax, rice bran wax, wood wax, and jojoba oil.

[0132] Examples of animal-derived waxes include beeswax, lanolin, and whale wax.

[0133] As mineral-based waxes, examples include lignite wax, oxkerite wax, and ceresin wax.

[0134] As petroleum waxes, examples include paraffin wax, microcrystalline wax, and petrolatum.

[0135] Synthetic waxes include synthetic hydrocarbons, modified waxes, hydrogenated waxes, fatty acids, amides, amines, imides, ester waxes, and ketones.

[0136] Examples of synthetic waxes include Fischer-Tropsch wax (also known as Sasol wax) and polyethylene wax. In addition, the following polymers that are low molecular weight polymers (specifically, polymers with a number average molecular weight of 500 to 20,000) can be listed: polypropylene, ethylene-acrylic acid copolymer, polyethylene glycol, polypropylene glycol, and block or graft copolymers of polyethylene glycol and polypropylene glycol.

[0137] Examples of modified waxes include lignite wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives. Here, "derivative" refers to compounds obtained through any treatment such as purification, oxidation, esterification, saponification, or a combination thereof. Examples of hydrogenated waxes include hydrogenated castor oil and hydrogenated castor oil derivatives.

[0138] From the viewpoint of excellent texture-forming properties based on phase separation, synthetic wax is preferred as the aforementioned low-polarity compound (A), with polyethylene wax being more preferred, and oxidized polyethylene wax being even more preferred.

[0139] It should be noted that when this composition is diluted with a solvent such as water to prepare a coating solution, the wax can be dispersed by surfactants to prepare a wax emulsion, which is then mixed into the coating solution.

[0140] From the viewpoint of phase separation-based texture formation properties and processability, the number-average molecular weight of synthetic waxes is typically in the range of 500–30,000, preferably 1,000–15,000, and more preferably 2,000–8,000. It should be noted that the number-average molecular weight is a polystyrene-converted value determined using gel permeation chromatography (GPC).

[0141] Furthermore, considering the possibility of heating during resin layer formation for cross-linking, the melting point or softening point of the wax is preferably 80°C or higher, more preferably 110°C or higher. On the other hand, from the viewpoint of controlling phase separation performance after heat treatment, the temperature is preferably 200°C or lower, more preferably 170°C or lower, and even more preferably 150°C or lower. Particularly when the heat treatment process becomes a trigger for phase separation, although uncertain, it is presumed that the wax melts and the melted wax repels other resins, thereby enabling the formation of protrusions.

[0142] It should be noted that the melting point of wax can be determined using a differential scanning calorimeter (DSC).

[0143] (Compounds containing long-chain alkyl groups)

[0144] Compounds containing long-chain alkyl groups refer to compounds having straight-chain or branched alkyl groups with 6 or more carbon atoms, preferably 8 or more, and more preferably 12 or more carbon atoms.

[0145] Examples of alkyl groups include hexyl, octyl, decyl, lauryl, octadecyl, and behenyl, which have approximately 6 to 30 carbon atoms. Compounds containing alkyl groups include, for example, various polymers containing long-chain alkyl groups, amines containing long-chain alkyl groups, ethers containing long-chain alkyl groups, and quaternary ammonium salts containing long-chain alkyl groups. Considering heat resistance, polymers are preferred; from the viewpoint of effectively obtaining moderate phase separation-based surface-forming properties with low content, polymers with long-chain alkyl groups as side chains are more preferred.

[0146] Polymer compounds having long-chain alkyl groups in their side chains can be obtained by reacting a polymer with a reactive group with a compound having an alkyl group that can react with that reactive group. Examples of such reactive groups include hydroxyl, amino, carboxyl, and acid anhydride groups. Examples of compounds having these reactive groups include polyvinyl alcohol, polyethyleneimine, polyethyleneamine, polyester resins containing reactive groups, and poly(meth)acrylic acid resins containing reactive groups. Among these, polyvinyl alcohol is preferred considering ease of processing. The degree of polymerization of the polyvinyl alcohol used is not particularly limited, but is generally 100 or more, preferably in the range of 300 to 40,000. In addition, the degree of saponification of polyvinyl alcohol is not particularly limited, but is generally 70 mol% or more, preferably in the range of 70 to 99.9 mol%, more preferably 80 to 97 mol%, and particularly preferably 86 to 95 mol%.

[0147] Examples of alkyl-containing compounds that can react with reactive groups include: hexyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate, behenyl isocyanate, and other isocyanates containing long-chain alkyl groups; hexanoyl chloride, octanoyl chloride, decanoyl chloride, lauroyl chloride, octadecyl acyl chloride, behenyl chloride, and other acyl chlorides containing long-chain alkyl groups; amines containing long-chain alkyl groups; and alcohols containing long-chain alkyl groups. Among these, isocyanates containing long-chain alkyl groups are preferred for ease of processing, and octadecyl isocyanate is particularly preferred.

[0148] In addition, polymers with long-chain alkyl groups in their side chains can also be obtained by polymerizing long-chain alkyl methacrylates or by copolymerizing long-chain alkyl methacrylates with other vinyl-containing monomers. Examples of long-chain alkyl methacrylates include hexyl methacrylate, octyl methacrylate, decyl methacrylate, lauryl methacrylate, octadecyl methacrylate, and behenyl methacrylate.

[0149] (Fluorine compounds)

[0150] As a fluorine compound, it is a compound containing fluorine atoms. Regarding the coating appearance based on online coating, organic fluorine compounds are suitable, such as compounds containing perfluoroalkyl groups, polymers of olefin compounds containing fluorine atoms, and aromatic fluorine compounds such as fluorobenzene. From the viewpoint of effectively obtaining unevenness-forming properties based on moderate phase separation with low content, compounds containing perfluoroalkyl groups are preferred. Furthermore, compounds containing long-chain alkyl groups as described above can also be used as fluorine compounds.

[0151] Examples of compounds containing perfluoroalkyl groups include perfluoroalkyl (meth)acrylates, perfluoroalkyl methyl (meth)acrylates, 2-perfluoroalkyl ethyl (meth)acrylates, 3-perfluoroalkyl propyl (meth)acrylates, 3-perfluoroalkyl-1-methylpropyl (meth)acrylates, 3-perfluoroalkyl-2-propylene (meth)acrylates, and other perfluoroalkyl-containing (meth)acrylates, and their polymers; perfluoroalkyl methyl vinyl ethers, 2-perfluoroalkyl ethyl vinyl ethers, 3-perfluoropropyl vinyl ethers, 3-perfluoroalkyl-1-methylpropyl vinyl ethers, 3-perfluoroalkyl-2-propylene vinyl ethers, and other perfluoroalkyl-containing vinyl ethers, and their polymers. Considering heat resistance, polymers are preferred. The polymer can be a single compound or a polymer of multiple compounds. Furthermore, from the viewpoint of effectively obtaining unevenness-forming properties based on moderate phase separation with a low content, the perfluoroalkyl group preferably has 3 to 11 carbon atoms. Furthermore, polymers containing long-chain alkyl compounds as described above may also be used. From the viewpoint of adhesion to the polyester film as the substrate, polymers with vinyl chloride are also preferred.

[0152] (organosilicon compounds)

[0153] Organosilicon compounds refer to compounds that have an organosilicon structure within their molecules. Examples include organosilicon emulsions, acrylic-grafted organosilicon, organosilicon-grafted acrylic, amino-modified organosilicon, perfluoroalkyl-modified organosilicon, and alkyl-modified organosilicon. If heat resistance is a consideration, a curable silicone resin is preferred.

[0154] As a type of curable silicone resin, any type of curing reaction can be used, such as addition type, condensation type, UV curing type, electron beam curing type, etc.

[0155] The content of compound (A) in this composition, based on its proportion to all non-volatile components in the composition, is preferably in the range of 5 to 90% by mass, more preferably 10 to 80% by mass, and even more preferably 20 to 60% by mass. By setting this content to 5% by mass or more, a sufficiently formed uneven structure based on phase separation can be achieved. Furthermore, by setting this content to 90% by mass or less, the content of other resins can be ensured, and the unevenness-forming properties based on phase separation can be appropriately adjusted.

[0156] (((Compound(B))))

[0157] This composition contains one or more compounds (B) selected from adhesive resins and crosslinking agents.

[0158] The aforementioned compound (B) can also help to form a fine, uneven structure through phase separation, thereby improving the coatability when the composition is made into a coating liquid.

[0159] ((adhesive resin))

[0160] The aforementioned adhesive resin selected as compound (B) is defined, according to the "Procedure for Safety Evaluation of Polymer Compounds" (November 1941, organized by the Chemical Substances Council), as a polymer compound with a number-average molecular weight (Mn) of 1000 or more as determined by gel permeation chromatography (GPC) and possessing film-forming properties.

[0161] There are no particular limitations on the (B) adhesive resin used; conventionally known adhesive resins can be used. Examples include (meth)acrylic resins, polyvinyl alcohol, polyester resins, ionically conductive polymers, and polyurethane resins. From the viewpoints of high hydrophilicity, maintenance of phase separation-based texture formation properties, and film formation, it is preferable to use at least one of (meth)acrylic resins, polyvinyl alcohol, and ionically conductive polymers; more preferably, at least one of (meth)acrylic resins and polyvinyl alcohol. In this composition, one type of adhesive resin can be used alone, or two or more types can be used in combination.

[0162] ((meth)acrylic resin)

[0163] (Meth)acrylic resins refer to polymers formed from polymerizable monomers containing acrylic and methacrylic monomers. They can be homopolymers or copolymers, as well as copolymers with polymerizable monomers other than acrylic and methacrylic monomers.

[0164] (Meth)acrylic polymers are polymers having structural units derived from (meth)acrylic acid or alkyl (meth)acrylic acid esters. (Meth)acrylic polymers can be polymers selected from at least one of (meth)acrylic acid and alkyl (meth)acrylic acid esters, or copolymers selected from at least one of them with at least one of monomers selected from other monomers, such as styrene or styrene derivatives, hydroxyl-containing monomers, etc.

[0165] Additionally, it also includes copolymers of these polymers with other polymers (such as polyesters, polyurethanes, etc.). Examples include block copolymers and graft copolymers. That is, (meth)acrylic resins can be (meth)acrylic modified polyester resins or (meth)acrylic modified polyurethane resins.

[0166] Alternatively, it may also include polymers (where applicable, mixtures of polymers) obtained by polymerizing polymeric monomers in a polyester solution or polyester dispersion. Similarly, it may also include polymers (where applicable, mixtures of polymers) obtained by polymerizing polymeric monomers in a polyurethane solution or polyurethane dispersion. Likewise, it may also include polymers (where applicable, mixtures of polymers) obtained by polymerizing polymeric monomers in other polymer solutions or dispersions, which are also considered (meth)acrylic-modified polyester resins and (meth)acrylic-modified polyurethane resins in this specification. It should be noted that the aforementioned polyesters and polyurethanes used in (meth)acrylic resins may be appropriately selected from the substances exemplified as polyesters and polyurethanes used as adhesive resins described later.

[0167] In addition, to further improve adhesion to polyester film, (meth)acrylic resins may also contain hydroxyl and amino groups.

[0168] The term "polymerizable monomer" is not particularly limited, but representative compounds include, for example, various carboxyl-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid, as well as their salts; various hydroxyl-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, monobutyl hydroxyfumarate, and monobutyl hydroxyitaconic acid; and methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and lauryl (meth)acrylate. Various alkyl methacrylates such as esters; various nitrogen-containing monomers such as (meth)acrylamide, diacetone acrylamide, or (meth)acrylonitrile; nitrogen-containing monomers such as N-hydroxymethyl (meth)acrylamide; various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, and vinyltoluene; various vinyl esters such as vinyl propionate; various silicon-containing polymerizable monomers such as γ-methacryloyloxypropyltrimethoxysilane and vinyltrimethoxysilane; phosphorus-containing vinyl monomers; various halogenated vinyl groups such as vinyl chloride and vinylidene chloride; and various conjugated dienes such as butadiene.

[0169] Of the above-mentioned (meth)acrylic resins, polymers formed by polymerizing polymerizable monomers containing acrylic and methacrylic monomers are preferred, and polymerizable monomers containing alkyl (meth)acrylic esters are more preferred.

[0170] Furthermore, the composition comprising (meth)acrylic resin is preferably prepared as a coating liquid by diluting it with a solvent as described below, preferably water as the main solvent (50% by mass or more). That is, from the viewpoint of making the coating liquid easily soluble or dispersed when it is aqueous, the polymerizable monomer preferably has hydrophilic groups such as hydroxyl and carboxyl groups. In addition, from the viewpoint of effectively obtaining an uneven structure through phase separation, it is also preferable to have hydrophilic groups such as hydroxyl and carboxyl groups.

[0171] Therefore, acrylic resins are preferably polymers formed by polymerizing polymerizable monomers containing alkyl (meth)acrylates and monomers containing hydrophilic groups, such as monomers containing hydroxyl groups and monomers containing carboxyl groups.

[0172] Alternatively, acrylic resins can be emulsion polymers formed by polymerizing polymerizable monomers in the presence of surfactants.

[0173] (Polyvinyl alcohol)

[0174] Polyvinyl alcohol (PVA) refers to compounds containing a PVA moiety, including modified compounds obtained by partially acetalizing or butyralizing PVA. Conventionally known PVAs can be used. The degree of polymerization of PVA is not particularly limited, but is typically 100 or higher, preferably in the range of 300 to 40,000. Setting the degree of polymerization to 100 or higher readily improves the water resistance of the resin layer. Furthermore, the degree of saponification of PVA is not particularly limited, but is typically 70 mol% or higher, preferably in the range of 70 to 99.9 mol%, more preferably 80 to 97 mol%, and even more preferably 86 to 95 mol% of polyvinyl acetate saponified products used in practical applications.

[0175] (Polyester resin)

[0176] For polyester resins, as major components, examples include resins formed from polycarboxylic acids and polyhydroxy compounds as described below.

[0177] That is, as polycarboxylic acids, terephthalic acid, isophthalic acid, phthalic acid, phthalic acid, 4,4'-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, potassium 2-sulfonate terephthalic acid, sodium 5-sulfonate isophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutaric acid, succinic acid, trimellitic acid, pyromellitic acid, pyromellitic tetracarboxylic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid, potassium trimellitic acid monopotassium salt, and their ester-forming derivatives can be used. As polyhydroxy compounds, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol, neopentanediol, 1,4-cyclohexanediol, terephthalic acid, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethyleneoxydiol, dimethylolpropionic acid, glycerol, trimethylolpropane, sodium dimethylol ethyl sulfonate, potassium dimethylolpropionate, etc., can be used to synthesize polyester resins by appropriately selecting one or more of these compounds and performing polycondensation reactions using conventional methods.

[0178] Furthermore, as part of the aforementioned polycarboxylic acid, it is preferable to use a substance obtained by copolymerizing sulfonyl isophthalic acids such as sodium isophthalate 5-sulfonate to introduce sulfonic acid groups into the polyester backbone, followed by neutralization and hydrophilization. The amount of copolymerization is typically 1 to 13 mol% relative to the total polycarboxylic acid, preferably 3 to 10 mol%, and more preferably 5 to 9 mol%. By appropriately introducing sulfonic acid groups, the hydrophilicity of the resin can be improved, making it easier to form an uneven structure. This, in turn, improves the water dispersion stability.

[0179] (Polymers with ionic conductivity)

[0180] Ionically conductive polymers refer to polymers containing ionically conductive functional groups, such as ammonium-containing compounds, polyether compounds, sulfonic acid compounds, and betaine compounds. Among these, compounds containing ammonium groups are particularly preferred from the viewpoint of high polarity and efficient formation of textures.

[0181] Ammonium-containing compounds are compounds that have an ammonium group within their molecules, and are preferably polymers containing an ammonium group. For example, polymers containing monomers having an ammonium group and an unsaturated double bond can be used.

[0182] As a specific example of this polymer, polymers having the constituent elements shown in formula (1-1-1) as repeating units can be listed. Homopolymers, copolymers, and other components can also be copolymerized.

[0183]

[0184] In the above equation (1-1-1), R 1 R 2 Each group can be independently composed of hydrogen atoms, alkyl groups, phenyl groups, etc., and these alkyl and phenyl groups can be substituted with groups as shown below. Substitutable groups include, for example, hydroxyl, amide, ester, alkoxy, phenoxy, naphthoxy, thioalkoxy, thiophenoxy, cycloalkyl, trialkylammonium alkyl, cyano, halogen, etc. Additionally, R... 1 and R 2 They can be chemically bonded; for example, -(CH2) can be listed. m -(m=an integer from 2 to 5), -CH(CH3)CH(CH3)-, -CH=CH-CH=CH-, -CH=CH-CH=N-, -CH=CH-N=C-, -CH2OCH2-, -(CH2)2O(CH2)2-, etc.

[0185] In the above formula (1-1-1), X - Appropriate selections may be made within the scope of the invention without prejudice to its spirit. Examples include halide ions, sulfonate ions, phosphate ions, nitrate ions, alkyl sulfonate ions, and carboxylate ions.

[0186] In the aforementioned polymers, namely polymers containing monomers with ammonium groups and unsaturated double bonds as components, from the viewpoint of improving film-forming properties and obtaining stable coatings, copolymerization with other monomers is possible.

[0187] Other monomers include, for example, alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate; and acrylamides such as N-hydroxymethylacrylamide.

[0188] Furthermore, from the viewpoint of further improving polarity and effectively forming unevenness, homopolymers with repeating elements as shown in the above formula (1-1-1) are preferred.

[0189] Furthermore, the number average molecular weight of the ammonium-containing compound is preferably 1,000 to 500,000, more preferably 2,000 to 350,000, and even more preferably 5,000 to 200,000. By setting the molecular weight to 1,000 or higher, it is possible to prevent the coating film from weakening and to easily achieve good heat resistance stability. Additionally, by setting the molecular weight to 500,000 or lower, it is possible to prevent the viscosity of the coating liquid from increasing, and to easily achieve good processability and coatability.

[0190] (Polyurethane resin)

[0191] Polyurethane resin refers to a polymeric compound containing urethane bonds within its molecule, preferably a water-dispersible or water-soluble substance. In this invention, it can be used alone or in combination of two or more types.

[0192] To impart water dispersibility or water solubility, it is preferable to introduce hydrophilic groups such as hydroxyl, carboxyl, sulfonic acid, sulfonyl, phosphate, and ether groups into the polyurethane resin. Among these hydrophilic groups, carboxyl or sulfonic acid groups are particularly preferred from the perspective of the adhesion between the resin layer and the polyester film.

[0193] One method for producing polyurethane resins is based on the reaction of hydroxyl-containing compounds with isocyanates. Suitable hydroxyl-containing compounds used as raw materials are polyols, such as polyester polyols, polyether polyols, polycarbonate polyols, polyolefin polyols, and acrylic polyols. These compounds can be used alone or in combination.

[0194] Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polyethylidene propylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol.

[0195] As polyester polyols, examples include substances obtained by reacting polycarboxylic acids or their anhydrides with polyols. Examples of polycarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, and isophthalic acid. Examples of polyols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-methyl-2-propyl-1,3-propanediol, 1,8- Octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexanediol, dihydroxymethylcyclohexane, dimethylbenzene, dihydroxyethoxybenzene, alkyldialkylolamine, lactone diol, etc.

[0196] As polycarbonate-based polyols, examples include polycarbonate diols obtained by reacting polyols with dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, etc., through a dealcoholization reaction, such as poly(1,6-hexanediol) carbonate and poly(3-methyl-1,5-pentanediol) carbonate.

[0197] Of the above, polyester polyols are preferred.

[0198] Examples of polyisocyanate compounds used to obtain polyurethane resins include aromatic diisocyanates such as toluene diisocyanate, phenylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate; aliphatic diisocyanates with aromatic rings such as α,α,α',α'-tetramethylphenylene diisocyanate; aliphatic diisocyanates such as methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, and hexamethylene diisocyanate; and alicyclic diisocyanates such as cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and isopropylidene dicyclohexyl diisocyanate. These compounds can be used alone or in combination.

[0199] Chain extenders can be used when synthesizing polyurethane resins. As a chain extender, there are no particular restrictions as long as it has two or more active groups that react with isocyanate groups. Generally, chain extenders with two hydroxyl or amino groups can be used.

[0200] Examples of chain extenders with two hydroxyl groups include aliphatic diols such as ethylene glycol, propylene glycol, and butanediol; aromatic diols such as benzenediethanol and dihydroxyethoxybenzene; and ester diols such as neopentyl glycol hydroxypentyl ester.

[0201] Examples of chain extenders having two amino groups include aromatic diamines such as toluenediamine, phenylenediamine, and diphenylmethanediamine; aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, 2,2-dimethyl-1,3-propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine; and alicyclic diamines such as 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, 1,4-diaminocyclohexane, and 1,3-diaminomethylcyclohexane.

[0202] ((crosslinking agent))

[0203] There are no particular limitations on the crosslinking agent selected as compound (B) mentioned above, and conventionally known crosslinking agents can be used. By using a crosslinking agent, a cured resin layer is easily formed. Examples of crosslinking agents include melamine compounds, oxazoline compounds, epoxy compounds, carbodiimide compounds, isocyanate compounds, and silane coupling compounds. From the viewpoint of ease of adjusting the unevenness-forming properties based on phase separation, at least one of melamine compounds and oxazoline compounds is preferably used as the crosslinking agent. In this composition, one crosslinking agent can be used alone, or two or more can be used in combination.

[0204] (Melamine compound)

[0205] Melamine compounds refer to compounds that have a melamine backbone in their structure, such as compounds that can be partially or completely etherified by reacting hydroxyalkylated melamine derivatives with alcohols, and mixtures thereof.

[0206] Examples of hydroxyalkylation include hydroxymethylation, hydroxyethylation, hydroxyisopropylation, hydroxyn-butylation, and hydroxyisobutylation. Among these, hydroxymethylation is preferred from a reactivity point of view.

[0207] The alcohols used in etherification are preferably methanol, ethanol, isopropanol, n-butanol, and isobutanol, among which methanol is more preferred.

[0208] Furthermore, the melamine compound can be a monomer, a polymer of more than one dimer, or a mixture thereof. Additionally, a substance obtained by co-condensing a portion of melamine with urea or the like can be used. To enhance the reactivity of the melamine compound, a catalyst can also be used in this composition.

[0209] (Oxazoline compounds)

[0210] Oxazoline compounds are compounds containing an oxazoline group within their molecules, particularly preferably polymers containing an oxazoline group. They can be prepared by addition polymerizability through polymerization of an oxazoline-containing monomer, either alone or with other monomers. Examples of addition polymerizable oxazoline-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline, and mixtures of one or more of these monomers can be used. Among these, 2-isopropenyl-2-oxazoline is readily available industrially and is suitable. There are no restrictions on other monomers as long as they can copolymerize with monomers containing oxazoline groups that are capable of addition polymerization. Examples include (meth)acrylates such as alkyl methacrylates (as alkyl groups, they are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-ethylhexyl, and cyclohexyl); unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene sulfonic acid, and their salts (sodium salts, potassium salts, ammonium salts, tertiary amine salts, etc.); unsaturated nitriles such as acrylonitrile and methacrylonitrile; (meth)acrylamide, N-alkyl(methyl)... Acrylamide and N,N-dialkyl(methyl)acrylamide (as alkyl groups, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-ethylhexyl, cyclohexyl, etc.) and other unsaturated amides; vinyl acetate, vinyl propionate and other vinyl esters; methyl vinyl ether, ethyl vinyl ether and other vinyl ethers; ethylene, propylene and other α-olefins; halogen-containing α,β-unsaturated monomers such as vinyl chloride, vinylidene chloride and other halogen-containing α,β-unsaturated monomers; styrene, α-methylstyrene and other α,β-unsaturated aromatic monomers, etc., may use one or more of these monomers.

[0211] In addition, oxazoline compounds can have polyoxyalkylene chains such as polyethylene oxide chains, for example, (meth)acrylates with polyoxyalkylene chains can be used as other monomers.

[0212] From the viewpoint of improving the adhesion of the resin layer to the polyester film, the amount of oxazoline group in the oxazoline compound is preferably 0.5 to 10 mmol / g, more preferably 1 to 9 mmol / g, and even more preferably 3 to 8 mmol / g.

[0213] (Epoxy compounds)

[0214] Epoxy compounds are compounds that have epoxy groups in their molecules, such as hydroxyl groups or condensates of hydroxyl groups and amino groups of epichlorohydrin, ethylene glycol, polyethylene glycol, glycerol, polyglycerol and bisphenol A, as well as polyepoxides, diepoxides, monoepoxides and glycidylamines.

[0215] Examples of polyepoxide compounds include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris(2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, and trimethylolpropane polyglycidyl ether.

[0216] Examples of diepoxide compounds include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcinol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and polytetramethylene glycol diglycidyl ether.

[0217] Examples of monoepoxide compounds include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, and phenyl glycidyl ether; examples of glycidylamine compounds include N,N,N',N'-tetraglycidyl-m-phenylenediamine and 1,3-bis(N,N-diglycidylamino)cyclohexane. From the viewpoint of improving the adhesion of the resin layer to the polyester film, polyether-based epoxy compounds are preferred.

[0218] Furthermore, the amount of epoxy groups is preferably a polyfunctional polyepoxide compound with three or more functions, compared to a difunctional compound.

[0219] (Carbodiimide compound)

[0220] Carbodiimide compounds refer to compounds having a carbodiimide structure, and are compounds with one or more carbodiimide structures in the molecule. For better adhesion between the resin layer and the polyester film, polycarbodiimide compounds with two or more carbodiimide structures in the molecule are preferred.

[0221] Carbodiimide compounds can be synthesized using previously known techniques, typically through the condensation reaction of diisocyanate compounds. There are no particular limitations on the diisocyanate compounds used; both aromatic and aliphatic compounds can be employed. Specifically, examples include toluene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate, and dicyclohexylmethane 4,4'-diisocyanate, among others.

[0222] The content of carbodiimide groups in the carbodiimide compound, expressed as carbodiimide equivalents (the weight [g] of the carbodiimide compound used to provide 1 mol of carbodiimide groups), is typically 100 to 1000, preferably 250 to 800, and more preferably 300 to 700. Using the compound within this range improves the durability of the resin layer.

[0223] Furthermore, without prejudice to the spirit of the present invention, in order to improve the water solubility and water dispersibility of the polycarbodiimide compound, surfactants or hydrophilic monomers such as quaternary ammonium salts of polyepoxides and dialkyl amino alcohols and hydroxyalkyl sulfonates may be added.

[0224] (Isocyanate compounds)

[0225] Isocyanate compounds refer to compounds with isocyanate or isocyanate-terminated compounds having an isocyanate derivative structure. Examples of isocyanates include aromatic isocyanates such as toluene diisocyanate, phenylene diisocyanate, methylene diphenyl diisocyanate, phenyl diisocyanate, and naphthalene diisocyanate; aliphatic isocyanates with aromatic rings such as α,α,α',α'-tetramethylphenylene diisocyanate; aliphatic isocyanates such as methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, and hexamethylene diisocyanate; and alicyclic isocyanates such as cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylene bis(4-cyclohexyl) isocyanate, and isopropylidene dicyclohexyl diisocyanate.

[0226] In addition, polymers and derivatives of these isocyanates, such as biuret compounds, isocyanurate compounds, urea diketides, and carbodiimide modifiers, can also be listed. They can be used alone or in combination. Among the above-mentioned isocyanates, aliphatic isocyanates or alicyclic isocyanates are preferred over aromatic isocyanates to avoid yellowing caused by ultraviolet light.

[0227] When used in the form of a capped isocyanate, the capping agents include, for example, bisulfites; phenolic compounds such as phenol, cresol, and ethylphenol; alcoholic compounds such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol, and ethanol; active methylene compounds such as methyl isobutyryl acetate, dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, and acetylacetone; thiol compounds such as butyl mercaptan and dodecyl mercaptan; lactam compounds such as ε-caprolactam and δ-valeronactam; amine compounds such as diphenylaniline, aniline, and ethyleneimine; amide compounds such as acetaniline and acetamide; and oxime compounds such as formaldehyde, acetaldehyde oxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime. These can be used alone or in combination of two or more.

[0228] In addition, isocyanate compounds can be used alone or in the form of mixtures or combinations with various polymers. For improving the dispersibility and crosslinking properties of isocyanate compounds, mixtures or combinations with polyester resins and polyurethane resins are preferred.

[0229] (Silane coupling compound)

[0230] Silane coupling compounds are organosilicon compounds that contain organic functional groups and hydrolytic groups such as alkoxy groups in a single molecule. Examples include: epoxypropylmethyldimethoxysilane, 3-epoxypropyltrimethoxysilane, 3-epoxypropylmethyldiethoxysilane, 3-epoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc., containing epoxy groups; vinyltrimethoxysilane, vinyltriethoxysilane, etc., containing vinyl groups; p-styryltrimethoxysilane, p-styryltriethoxysilane, etc., containing styryl groups; 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, etc., containing (meth)acryloyl groups; 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, etc. Amino compounds such as silanes, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-phenyl-3-aminopropyltriethoxysilane; isocyanurate compounds such as tris(trimethoxysilylpropyl)isocyanurate and tris(triethoxysilylpropyl)isocyanurate; mercapto compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane.

[0231] The content of compound (B) in this composition, based on its proportion to all non-volatile components in the composition, is preferably in the range of 5 to 95% by mass, more preferably 10 to 80% by mass, and even more preferably 20 to 60% by mass. By setting this content to 10% by mass or more, it is possible to balance the formation of the uneven structure based on phase separation and the improvement of coatability when the composition is formulated into a coating liquid. In addition, by setting this content to 95% by mass or less, it is possible to ensure the content of a single resin, and the unevenness-forming properties based on phase separation can be appropriately adjusted.

[0232] (((Specially Preferred Method)))

[0233] The compounds (A) and (B) contained in this composition are particularly preferred to be (a) a low-polarity compound and an adhesive resin, (b) a low-polarity compound and a crosslinking agent, and (c) a combination of a low-polarity compound, an adhesive resin and a crosslinking agent, especially the combination of (c).

[0234] (((Compound(C))))

[0235] When a crosslinking agent is included as the aforementioned compound (B), the composition may further include (C) a crosslinking catalyst (compound (C)).

[0236] The aforementioned (C) crosslinking catalyst is used to improve the reactivity of the crosslinking agent, and various known catalysts can be used. Examples include amine compounds, salts of amine compounds, aromatic sulfonic acid compounds such as p-toluenesulfonic acid, organic acids such as phosphoric acid compounds and their salts, imine compounds, amidine compounds, guanidine compounds, organometallic compounds, zinc stearate, zinc myristate, aluminum stearate, calcium stearate, and other metal salts. Among these, amine compounds, salts of amine compounds, and p-toluenesulfonic acid are preferred, and amine compounds and salts of amine compounds are more preferred.

[0237] When this composition contains a crosslinking catalyst, the content of the crosslinking catalyst (compound (C)) in the composition, based on its proportion to all non-volatile components in the composition, is preferably in the range of 0.01 to 5% by mass, more preferably 0.1 to 4% by mass, and even more preferably 1 to 3% by mass. By setting the content within this range, the reduction in the pot life can be suppressed, and in addition, the unevenness-forming performance based on phase separation becomes sufficient.

[0238] (((Compound(D))))

[0239] This composition may contain (D) microparticles (compound (D)). By using microparticles in combination, the surface hardness of the protrusions in the resin layer with its uneven structure can be further improved. By improving the surface hardness of the protrusions, the protrusions on the surface of the resin layer are less prone to deformation even when the laminated polyester film is rolled into a roll, resulting in a good roll appearance. Especially when the composition consists of resin alone, the protrusions are soft, and therefore deform when rolled into a roll, compressing the air passages and sometimes preventing the full realization of the original excellent processability. Therefore, it is also preferable to include microparticles.

[0240] Examples of the aforementioned (D) particles include inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, alumina, and titanium dioxide; and organic particles such as cross-linked polymers such as cross-linked silicone resin particles, cross-linked acrylic resin particles, cross-linked styrene-acrylic resin particles, and cross-linked polyester particles, as well as calcium oxalate and ion exchange resins. Among these, silica and alumina are preferred.

[0241] The average particle size of the aforementioned (D) particles is preferably 1 to 100 nm, more preferably 2 to 60 nm, and even more preferably 3 to 30 nm. If the average particle size is within the range described above, the generation of coarse protrusions caused by particle aggregation and the contamination of the process caused by particle shedding can be suppressed, and the desired fine textured structure can be easily obtained.

[0242] It should be noted that the methods for determining the average particle size include: methods calculated based on the specific surface area measured by a specific surface area measuring device and the particle density; methods calculated by observing the particle diameter using a transmission electron microscope (TEM) or a scanning electron microscope (SEM); and methods determined by measurement based on dynamic light scattering. The average particle size can be determined by appropriate methods.

[0243] When this composition contains microparticles, the content of the microparticles (compound (D)) in the composition, based on the proportion of all non-volatile components in the composition, is preferably in the range of 1 to 50% by mass, more preferably 10 to 45% by mass, and even more preferably 22 to 40% by mass. By setting the content within the range described above, the surface hardness of the protrusions can be improved, and a desired fine textured surface can be obtained.

[0244] (((Other ingredients)))

[0245] In addition, without prejudice to the spirit of the present invention, in addition to the above-mentioned components, defoamers, coatability modifiers, surfactants, thickeners, organic lubricants, ultraviolet absorbers, antioxidants, foaming agents, dyes, pigments and other additives may be further appropriately mixed in.

[0246] ((solvent))

[0247] This composition can be diluted with a solvent to prepare a coating liquid. That is, this composition can be coated onto, for example, this polyester film in the form of a liquid coating liquid, dried and cured as needed, thereby forming a resin layer.

[0248] It should be noted that the components constituting this composition (compounds (A) and (B), any added (C) crosslinking catalyst and (D) particles, other components, etc.) can be dissolved in a solvent or dispersed in a solvent.

[0249] When preparing a coating solution, the concentration of all non-volatile components of the composition in the coating solution is preferably 0.1% to 50% by mass. If it is 0.1% by mass or more, a resin layer of the desired thickness can be formed efficiently. On the other hand, if it is 50% by mass or less, the appearance of the resin layer can be improved by suppressing the viscosity during coating, and the stability of the coating solution can also be improved.

[0250] As the aforementioned solvent, there is no particular limitation, and both water and organic solvents can be used. From the viewpoint of environmental protection, it is preferable to use water as the main solvent (accounting for 50 mass% or more of the total solvent) to prepare an aqueous coating liquid. The content of water is preferably 60 mass% or more, more preferably 70 mass% or more. The aqueous coating liquid may contain a small amount of organic solvents. Specifically, the amount of the organic solvent is appropriately not more than the amount of water on a mass basis. For example, it may be 50 mass% or less of the total solvent, preferably 40 mass% or less, more preferably 30 mass% or less.

[0251] Examples of organic solvents used in combination with water include alcohols such as ethanol, isopropanol, ethylene glycol and glycerol; ethers such as ethyl cellosolve, tert-butyl cellosolve, propylene glycol monomethyl ether and tetrahydrofuran; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; amines such as dimethylethanolamine. They can be used alone or in combination. By appropriately selecting and containing these organic solvents in the aqueous coating liquid according to needs, the stability and coatability of the coating liquid can sometimes be improved.

[0252] In addition, when only an organic solvent is used as the above solvent, examples of the organic solvent include aromatic hydrocarbons such as toluene; aliphatic hydrocarbons such as hexane, heptane and isooctane; esters such as ethyl acetate and butyl acetate; ketones such as methyl ethyl ketone and isobutyl methyl ketone; alcohols such as ethanol and 2-propanol; ethers such as diisopropyl ether and dibutyl ether. These can be used alone in consideration of solubility, coatability, boiling point and the like, or can be mixed and used in combination.

[0253] It can be inferred that there are unreacted products, reacted compounds or mixtures thereof of each component (compounds (A) and (B), optionally added (C) crosslinking catalyst, (D) fine particles, other components, etc.) constituting the composition in the resin layer.

[0254] It should be noted that the analysis of each component in the resin layer can be performed by, for example, TOF-SIMS, ESCA, fluorescence X-ray, etc.

[0255] <Hansen solubility parameter>

[0256] Each component (compounds (A) and (B)) constituting the composition can also be illustrated by the Hansen solubility parameter (HSP). More specifically, the concave-convex structure of the resin layer is a fine shape formed by phase separation as described above, and this phase separation can be described using HSP.

[0257] The Hansen solubility parameter (HSP) is an indicator of how much a substance dissolves in another substance. HSP is a three-dimensional parameter that divides the solubility parameter introduced by Hildebrand into three components: dispersion term δd, polarity term δp, and hydrogen bonding term δh.

[0258] The dispersion term δd represents the effect based on dispersion forces, the polarity term δp represents the effect based on dipole forces, and the hydrogen bonding term δh represents the effect based on hydrogen bonding forces, as described below.

[0259] It should be noted that the units for each are MPa. 0.5 .

[0260] δd: Energy originating from intermolecular dispersion forces

[0261] δp: Energy originating from intermolecular polar forces

[0262] δh: Energy derived from intermolecular hydrogen bonding forces.

[0263] The definition and calculation of HSP are described in the following literature.

[0264] Charles M. Hansen, Hansen Solubility Parameters: A Users Handbook (CRCpress, 2007).

[0265] Specifically, the dispersion term reflects the effect of London dispersion force, the polarity term reflects the effect based on dipole moment, and the hydrogen bonding term reflects the effect based on water, alcohol, etc.

[0266] Furthermore, based on HSP, substances with similar vectors can be judged to have high solubility, and the similarity of vectors can be judged by the distance between HSPs (HSP distance).

[0267] In this invention, the HSP [δd, δp, δh] of the resin (as described above, corresponding to compounds (A) and (B)) can be used to evaluate its solubility in various solvents with known HSPs. Solvents in which the resin dissolves are considered good solvents, and solvents in which the resin does not dissolve or swell are considered bad solvents. The interaction sphere and the HSP at its center are calculated.

[0268] The thresholds for good and bad solvents can be calculated using software such as HSP (Hansen Solubility Parameters in Practice), which is commercially available. The thresholds are determined by finding the closest fit value to 1 for the calculated interaction sphere. For accurate measurements, solvents can be used with multiple HSPs [δD, δP, δH], as shown in Table 1. Following Table 1, solubility tests are performed using at least 18 solvents to determine whether they are good or bad solvents. It should be noted that "≥1" in the table refers to testing with one or more solvents, and "≥2" refers to testing with two or more solvents.

[0269] [Table 1]

[0270] Table 1

[0271]

[0272] In addition, if the chemical structure is well known, the HSP[δd, δp, δh] of the resin can be calculated using the Y-MB (Yamamoto Molecular Break) function of HSP. If the chemical structure is not well known, it can also be determined by experimental measurement using previously known methods.

[0273] Alternatively, by dissolving the formed resin layer in a suitable solvent, separating the components, and then using the same method as described above, the HSP of the resin in the resin layer can also be determined.

[0274] Compounds (A) and (B) preferably comprise at least one compound selected from compound (A) and at least one compound selected from compound (B) that satisfy the following formula (1-1-2).

[0275] HSP distance = {4×(δd1-δd2)} 2 +(δp1-δp2) 2 +(δh1-δh2) 2} 0.5 ≥5.0···(1-1-2)

[0276] In this context, δd1, δp1, and δh1 represent the δd, δp, and δh of compound (A) in the Hansen solubility parameters [δd, δp, δh], while δd2, δp2, and δh2 represent the δd, δp, and δh of compound (B). It should be noted that δp1 ≤ δp2.

[0277] The HSP distance defined by formula (1-1-2) above is 5.0 or more, preferably 6.0 or more, more preferably 7.0 or more, and even more preferably 8.0 or more. If the HSP distance is within this range, the composition containing resins with different compatibility is more likely to cause phase separation, and even if the resin layer is a thin film, it can have the desired fine uneven structure. The HSP distance defined by formula (1-1-2) above is not particularly limited, but is preferably 25.0 or less, more preferably 23.0 or less, and even more preferably 21.0 or less.

[0278] In order to say that the relationship of the above formula (1-1-2) is satisfied, there is no particular restriction on the compounds (resins) used as compounds (A) and (B). When selecting one of each of the two resins as the object, at least one of the combinations of the two resins in the thought can satisfy the relationship of the above formula (1-1-2).

[0279] For example, if the compound (A) contained in this composition is either resin A-1 or resin A-2, and the compound (B) contained in this composition is either resin B-1 or resin B-2, then the possible combinations when selecting two resins for compounds (A) and (B) are resin A-1 and resin B-1, resin A-1 and resin B-2, resin A-2 and resin B-1, and resin A-2 and resin B-2. Therefore, the above means that as long as one or more of these four types satisfies the relationship in equation (1-1-2) above, it is acceptable.

[0280] In other words, as long as the combination of the two resins with the greatest HSP distance among the above four types (the farthest distance between the two resins) satisfies the relationship of the above formula (1-1-2), it is acceptable.

[0281] Next, the HSPs of compounds (A) and (B) illustrated above will be explained respectively.

[0282] (((HSP of compound (A))))

[0283] From the viewpoint of forming a fine, uneven structure based on phase separation, the polar term δp1 of compound (A) is preferably 9.0 MPa. 0.5 Hereinafter, 8.0 MPa is preferred. 0.5 Hereinafter, 7.0 MPa is further preferred. 0.5 Below. If the value of the polarity term δp1 is within the specified range, the polarity of compound (A) can be reduced, making it easier to satisfy the relationship in equation (1-1-2) above, and resulting in the formation of the desired uneven structure. The value of the polarity term δp1 of compound (A) is not particularly limited, but is preferably 1.0 MPa. 0.5 The above, and more preferably 2.0 MPa 0.5The polarity term δp1 of compound (A) is usually less than or equal to the polarity term δp2 of compound (B).

[0284] Furthermore, the hydrogen bond term δh1 of compound (A) is preferably 15.0 MPa. 0.5 The following, or more preferably, is 12.0 MPa 0.5 The following, and more preferably, is 9.0 MPa. 0.5 Below. On the other hand, the hydrogen bond term δh1 of compound (A) is preferably 1.0 MPa. 0.5 The above, and more preferably 3.0 MPa 0.5 The above, and more preferably 5.0 MPa 0.5 The above. If it is above the lower limit value, it can prevent the hydrogen bond term of compound (A) from becoming too low, and thus can prevent the following situations: layer separation due to reduced interaction with compound (B), and inability to form an uneven shape.

[0285] Furthermore, the dispersion term δd1 of compound (A) is not particularly limited, but is preferably 6.0 MPa. 0.5 The above, and more preferably 8.0 MPa 0.5 The above, and more preferably 10.0 MPa 0.5 above.

[0286] If the values ​​of the hydrogen bonding term δh1 and / or the dispersion term δd1 are within the range described above, then the relationship of the above equation (1-1-2) can be easily satisfied.

[0287] It should be noted that when this composition contains two or more compounds (A), at least one compound (A) may have the value of the polarity term δp1 mentioned above, or all compounds (A) may have the value of the polarity term δp1 mentioned above. The same applies to the hydrogen bonding term δh1 and the dispersion term δd1.

[0288] (((HSP of compound (B))))

[0289] From the viewpoint that it also helps to form a fine, uneven structure based on phase separation, thereby improving the coatability when the composition is made into a coating liquid, the hydrogen bond term δh2 of compound (B) is preferably 7.5 MPa. 0.5 The above, and more preferably 8.0 MPa 0.5 The above, and more preferably 9.0 MPa 0.5 The above applies. If the value of the hydrogen bond term δh2 is within the specified range, the hydrophilicity of compound (B) can be improved, thus improving its coatability. Furthermore, the relationship in equation (1-1-2) above is easily satisfied, resulting in the easy formation of the desired uneven structure.

[0290] Furthermore, the hydrogen bond term δh2 of compound (B) is preferably 25.0 MPa. 0.5The following, or more preferably, is 23.0 MPa 0.5 The following, and more preferably, is 20.3 MPa. 0.5 The following method is used to prevent the hydrophilicity from becoming too high by keeping the value of the hydrogen bond term δh2 below a certain level. This prevents the coating from absorbing water and softening, reducing its surface roughness, and improving its sliding properties.

[0291] Furthermore, the polar term δp2 of compound (B) is preferably 7.0 MPa. 0.5 The above, and more preferably 8.0 MPa 0.5 The above, and more preferably 9.0 MPa 0.5 The dispersion term δd2 is not particularly limited, but is preferably 6.0 MPa. 0.5 The above, and more preferably 8.0 MPa 0.5 The above, and more preferably 10.0 MPa 0.5 The above. If the values ​​of the hydrogen bonding term δh2 and / or the dispersion term δd2 are within the range described above, then the relationship of equation (1-1-2) above is easily satisfied.

[0292] It should be noted that when this composition contains two or more compounds (B), at least one compound (B) may have the above-mentioned hydrogen bonding term δh2 value, or all compounds (B) may have the above-mentioned hydrogen bonding term δh2 value. The same applies to the polarity term δp2 and the dispersion term δd2.

[0293] This resin layer must contain at least two resins: one selected from compound (A) and one selected from compound (B). From the viewpoint of easier adjustment of the uneven shape and thus control over adhesion to the polyester film and coating strength, it is preferable to contain three or more resins. In this case, it is preferable to consider not only the furthest distance between the aforementioned two resins but also the distance to the resin of the third component. It should be noted that the resin of the third component can be selected from compound (A), compound (B), or other compounds, but is preferably selected from at least compound (B).

[0294] As a more preferred approach, it can be listed that the polarity term δp1 of compound (A) is 9.0 MPa. 0.5 Based on the following, in the case of resins containing an HSP distance of 19.0 or more relative to compound (A), resins containing an HSP distance of 15.0 or less are also included. The HSP distance in this case is calculated using the relationship determined by the above formula (1-1-2).

[0295] If the above conditions can be met, the fine, uneven structure can be more effectively manifested through phase separation. From this point of view, it is more preferable to include a value of 9.0 MPa relative to the polarity term δp1. 0.5The following compound (A) has an HSP distance of 7.0 or more, and it is even more preferable to include a resin with an HSP distance of 8.0 or more. In addition, when the resin with an HSP distance of 19.0 or more is included, it is more preferable to further include a resin with an HSP distance of 15.0 or less, and it is even more preferable to include a resin with an HSP distance of 13.0 or less.

[0296] <Methods for forming resin layers>

[0297] Next, the method for forming the resin layer constituting this laminated polyester film will be described.

[0298] This resin layer is formed by coating the composition onto a polyester film and then subjecting the coated composition to drying, curing, heat treatment, or other treatments as needed, preferably at least heat treatment. The method of coating the resin composition is not particularly limited; for example, conventionally known coating methods such as reverse gravure coating, direct gravure coating, roll coating, die coating, rod coating, and curtain coating can be used.

[0299] Furthermore, methods for forming the resin layer include online coating and offline coating. There are no particular limitations on the method of heat-treating the coated resin composition. For example, when the resin layer is formed by offline coating, heat treatment is typically performed at 80–200°C for 3–40 seconds, preferably at 100–180°C for 3–40 seconds. On the other hand, when the resin layer is formed by online coating, heat treatment is typically performed at 70–280°C for 3–200 seconds.

[0300] Alternatively, heat treatment can be performed in two or more stages at different temperatures within the aforementioned temperature range. At least part of the heat treatment can be carried out by heating during stretching. Furthermore, drying and curing are preferably performed simultaneously by the heating during the aforementioned heat treatment.

[0301] In this invention, the resin layer is preferably formed by online coating, which involves treating the surface of the polyester film during the film-making process.

[0302] Online coating is a coating method performed within the polyester film manufacturing process. Specifically, it is a coating method performed at any stage from after the polyester is melt-extruded until it is stretched, heat-cured, and rolled up. Typically, coating is performed on any film among the following: unstretched sheets obtained by melting and quenching, uniaxially stretched films after stretching, biaxially stretched films before heat curing, and films after heat curing and before rolling up.

[0303] Not limited to the following, for example, in sequential biaxial stretching, especially after coating a uniaxially stretched film stretched along the length direction (longitudinal direction), the method of stretching in the transverse direction is excellent. According to this method, film formation and resin layer formation can be performed simultaneously, thus offering advantages in manufacturing costs. In addition, since stretching is performed after coating, the thickness of the resin layer can be varied according to the stretching ratio, making film coating easier compared to offline coating.

[0304] In addition, by providing a resin layer on the film before stretching, the resin layer can be stretched together with the polyester film, thereby enabling the resin layer to be firmly bonded to the polyester film.

[0305] Furthermore, in the manufacture of biaxially stretched polyester film, by using clamps or the like to fix the film ends and stretch it, the film can be restricted in both the longitudinal and transverse directions. In the subsequent heat treatment (heat setting process), high temperature can be applied in a state that does not form wrinkles and maintains planarity.

[0306] Therefore, the heat treatment performed after coating can be set to a high temperature that is impossible to achieve by other methods, thus improving the film-forming properties of the resin layer and enabling a stronger and more secure bond between the resin layer and the polyester film. Furthermore, a robust resin layer can be formed, improving properties such as resistance to migration and damp heat that can be formed on the resin layer.

[0307] Furthermore, whether offline or online coating is used, heat treatment and active energy radiation such as ultraviolet irradiation can be combined as needed. The polyester film constituting this laminated polyester film can be pre-treated with surface treatments such as corona treatment and plasma treatment.

[0308] The preferred coating amount of the non-volatile components in this resin layer is 0.005–0.95 g / m². 2 More preferably, it is 0.01–0.5 g / m 2 Further preferably, it is 0.02–0.2 g / m 2 If the coating amount is within the specified range, a fine, uneven structure can be formed through phase separation.

[0309] It should be noted that the coating amount can be calculated based on the concentration of non-volatile components in the coating liquid, the coating amount before drying derived from the consumption of the coating liquid, the transverse stretch ratio, etc.

[0310] In addition, the amount of non-volatile components coated is the amount of coating in this laminated polyester film, for example, the amount of coating after drying and stretching in the case of drying and stretching.

[0311] <<<Properties of Laminated Polyester Films>>>

[0312] The bearing length ratio (Rmr(80)) of the roughness curve of the resin layer surface of this laminated polyester film at a cut level of 80% is less than 76%.

[0313] The support length ratio (Rmr(c)) is one of the line roughness parameters (JIS B 0601), which represents the ratio of the support length ML(c) of the profile curve element cut at the horizontal level c (height % or μm) to the evaluation length Ln, and is calculated by the following equation (1-1-3).

[0314]

[0315] Here, the inventors believe that the support length ratio (Rmr(80)) is effective as an indicator of the concave-convex distribution of the concave-convex structure. For example, the value of the support length ratio (Rmr(80)) decreases when the concave distribution is large, and the value of the support length ratio (Rmr(80)) increases when the convex distribution is large. The smaller the support length ratio (Rmr(80)), the larger the gap formed between the films when the film is wound into a roll, the easier it is to expel air, and the better the winding performance.

[0316] The bearing length ratio (Rmr(80)) of the roughness curve at 80% of the cutting level is, as described above, 76% or less, preferably 70% or less, more preferably 65% ​​or less, and particularly preferably 58% or less. The lower limit is not particularly limited, but is approximately 1%, preferably 4%, and more preferably 6%.

[0317] The aforementioned support length ratio (Rmr(80)) can be adjusted by the composition, content, etc. of this composition.

[0318] Furthermore, the bearing length ratio (Rmr(50)) of the roughness curve at a cut level of 50% of the resin layer surface is 60% or less, more preferably 40% or less, and even more preferably 20% or less. The lower limit is not particularly limited, but is approximately 1%, preferably 3%, and more preferably 5%.

[0319] Here, the inventors believe that it is effective to consider the support length ratio (Rmr(80)) as an indicator of the unevenness distribution of the uneven structure, in addition to considering the support length ratio (Rmr(80)). For example, even with the same support length ratio (Rmr(80)), it can be said that a smaller support length ratio (Rmr(50)) results in a finer convex shape, and a larger support length ratio (Rmr(50)) results in a coarser convex shape. Therefore, the smaller the support length ratio (Rmr(50)), the finer the unevenness, the larger the gap formed between the films when the film is wound into a roll, the easier it is to expel air, and the better the winding performance.

[0320] The aforementioned support length ratio (Rmr(50)) can also be adjusted by the composition, content, etc. of this composition.

[0321] Furthermore, the arithmetic mean roughness (Ra) of the resin layer surface is preferably 5 nm or more, more preferably 20 nm or more, even more preferably 30 nm or more, and particularly preferably 35 nm or more. There is no particular upper limit, but 600 nm is preferred, more preferably 400 nm, and even more preferably 200 nm. If the arithmetic mean roughness (Ra) is 5 nm or more, the resin layer can be said to have a fine uneven structure, resulting in good processability of the laminated polyester film. Conversely, if the arithmetic mean roughness (Ra) is 600 nm or less, the uneven structure of the resin layer can be considered sufficiently fine.

[0322] Arithmetic mean roughness (Ra) is one of the line roughness parameters (JIS B 0601), representing the average value of the average height difference from the mean surface.

[0323] That is, extract a portion of the reference length L, set the average line of the extracted portion as the x-axis, set the direction of the vertical magnification as the y-axis, and use y=Z(x) to represent the roughness curve, which is then calculated according to the following formula (1-1-4).

[0324]

[0325] Furthermore, the ten-point average roughness (Rzjis) of the resin layer surface is preferably 28 nm or more, more preferably 70 nm or more, even more preferably 90 nm or more, and particularly preferably 120 nm or more. There is no particular upper limit, but 800 nm is preferred, more preferably 600 nm, and even more preferably 500 nm. If the ten-point average roughness (Rzjis) is 28 nm or more, the resin layer can be said to have a sufficiently uneven structure. Conversely, if the ten-point average roughness (Rzjis) is 800 nm or less, the uneven structure of the resin layer can be considered to be a sufficiently fine shape.

[0326] The ten-point average roughness (Rzjis) is one of the line roughness parameters (JIS B 0601). It represents the sum of the average of the fifth peak height (Zp) and the fifth valley depth (Zv) along the reference length L, and is calculated according to the following formula (1-1-5).

[0327]

[0328] The arithmetic mean roughness (Ra) and ten-point mean roughness (Rzjis) mentioned above can be adjusted by the composition, content, etc. of this composition.

[0329] It should be noted that the bearing length ratio (Rmr(80)), bearing length ratio (Rmr(50)), arithmetic mean roughness (Ra), and ten-point mean roughness (Rzjis) of the resin layer surface were measured using an atomic force microscope (scanning probe microscope) according to the method described in the examples. Measurements based on an atomic force microscope (scanning probe microscope) can capture finer surface structures, resulting in values ​​that strongly reflect the effects of the resin layer.

[0330] The arithmetic mean roughness (Sa) of the surface of the laminated polyester film opposite to the surface of the resin layer is preferably 15 nm or less, more preferably 9 nm or less, and even more preferably 5 nm or less. On the other hand, from the viewpoint of the processability of the film, this arithmetic mean roughness (Sa) is preferably 0.3 nm or more.

[0331] Average surface roughness (Sa) is one of the surface roughness parameters (ISO 25178). It is obtained by expanding the two-dimensional Ra (arithmetic mean roughness of a line) to three dimensions. It is the value obtained by dividing the volume of the part surrounded by the surface shape and the average surface by the measured area, and is calculated by the following formula (1-1-6).

[0332] When the surface is set as the XY plane and the height direction is set as the Z axis, if A is set as the defined region (set as the entire image) and Z(x, y) is set as the height of the image point (x, y) from the plane with height 0, then the result is as follows.

[0333]

[0334] Furthermore, the maximum peak height (Sp) on the side of the laminated polyester film opposite to the resin layer surface is preferably 800 nm or less, more preferably 500 nm or less, and even more preferably 100 nm or less. On the other hand, there is no particular limitation on the lower limit of this maximum peak height (Sp), but from the viewpoint of film processability, it is preferably 5 nm or more, more preferably 10 nm or more, and even more preferably 20 nm or more.

[0335] The maximum peak height (Sp) is one of the surface roughness parameters (ISO 25178), which represents the maximum height of the surface above the average surface, as shown in the following equation (1-1-7).

[0336]

[0337] When this laminated polyester film is used as a release film for forming green sheets of laminated ceramic capacitors, a release substrate for interlayer insulating resin, or a substrate for dry film resist, processing is performed utilizing the smoothness of the film. In this case, it is preferable that at least one side of this laminated polyester film is smooth. It should be noted that if the arithmetic mean roughness (Sa) and maximum peak height (Sp) of the side opposite to the side where the resin layer is formed are within the above-mentioned range, it can be considered smooth, with less transfer of unevenness and protrusions on the film surface, allowing for good processing.

[0338] It should be noted that the arithmetic mean roughness (Sa) and maximum peak height (Sp) of the side opposite to the resin layer surface can be measured by a non-contact surface roughness meter using optical interference, specifically by the method described in the examples.

[0339] The static friction coefficient between the resin layer surface and the opposite side of the laminated polyester film is preferably 1.0 or less, more preferably 0.8 or less, and even more preferably 0.6 or less.

[0340] When the laminated polyester film is wound into a roll, the coefficient of friction between the resin layer surface and the opposite side is important because the resin layer surface is in contact with the opposite side.

[0341] Therefore, if the static friction coefficient is within the specified range, the sliding properties become good due to the uneven structure of the resin layer, thus optimizing the operability of the laminated polyester film.

[0342] It should be noted that the above-mentioned static friction coefficient can be measured using the method described in the examples.

[0343] The air leakage index can be used as an indicator of the operability of the laminated polyester film, such as its rollability. A low air leakage index allows air trapped during film winding to escape easily, preventing defects in the roll appearance such as wrinkles and uneven end faces. Conversely, a high air leakage index means that trapped air is expelled after sufficient time, especially during transport, causing the film to shift in the core direction or develop scratches due to this shift, which becomes a problem.

[0344] An air leakage index of less than 130,000 seconds is acceptable. If it is less than 130,000 seconds, it can be said to be feasible to implement.

[0345] In addition to improving the air leakage index through the uneven structure of the resin layer, it can also be improved through the roughness of the smooth surface of the polyester film. As described above, it is preferable that the arithmetic mean roughness (Sa) of the side opposite to the surface where the resin layer is formed (i.e., the smooth surface) is 15 nm or less, and the maximum peak height (Sp) is 800 nm or less. In this case, the air leakage index is preferably 10,000 seconds or less, more preferably 8,000 seconds or less, and even more preferably 7,000 seconds or less. Here, the opposite surface can be the film surface used for processing in various applications such as the laminated polyester film for use as a release film for forming the green sheet of a laminated ceramic capacitor, a release substrate for interlayer insulating resin, or a substrate for dry film resist, etc. For example, it can be coated or laminated with various materials as described later.

[0346] On the other hand, when more precise processing is required, as described above, it is more preferable to satisfy either or both of the following: the arithmetic mean roughness (Sa) of the opposite side (i.e., the smooth surface of the film used for processing) is 9 nm or less, and the maximum peak height (Sp) is 500 nm or less. In this case, the air leakage index is preferably 130,000 seconds or less, more preferably 100,000 seconds or less, further preferably 70,000 seconds or less, and particularly preferably 50,000 seconds or less. In this way, when the smooth surface of the film is extremely smooth, more precise processing can be performed by utilizing the smoothness of the film, and the air leakage index is improved to the above range by the uneven structure of this resin layer, the rollability becomes good, and the operability of this laminated polyester film is optimized.

[0347] Thus, the air leakage index depends on the smoothness of the side opposite to the surface where the resin layer is formed, and therefore it is preferable to set it to a numerical range that corresponds to each smoothness level. More specifically, by setting the air leakage index to the aforementioned numerical range, the improved operability resulting from the uneven structure of the resin layer can be obtained, and therefore this is preferable.

[0348] It should be noted that the air leakage index described above can be measured using the method described in the examples.

[0349] <<<Applications of Laminated Polyester Films>>>

[0350] The resin layer is characterized by being composed of a resin composition containing specific compounds and having a specific roughness structure, thereby enabling even thin films to form a phase-separated structure and exhibit a fine uneven structure. Furthermore, it is characterized by using the bearing length ratio (Rmr(80)) as an indicator of the roughness structure to represent the unevenness distribution.

[0351] Based on this design concept, it is possible to achieve precise control of fine, uneven structures that are difficult to achieve in conventional granular compounding film manufacturing methods. Furthermore, by having a specific roughness structure, even thin films can have improved air expulsion ease, resulting in laminated polyester films with excellent handling properties.

[0352] This laminated polyester film can be used for a variety of purposes to improve operability, and its use is not particularly limited.

[0353] As described above, due to its fine, uneven structure, it exhibits excellent rollability when used for sheet forming, particularly when winding a highly smooth film into a roll, and is less prone to wrinkling. Therefore, it is suitable for use as a polyester film for sheet forming. Examples of polyester films for sheet forming include those used for green sheet forming of multi-layer ceramic capacitors (MLCCs), interlayer insulating resins, dry film resists (DFRs), and various demolding / processing applications such as those for multilayer circuit boards. This laminated polyester film is used, for example, as a support in demolding / processing applications.

[0354] Polyester films for sheet forming can be used in various sheet forming processes, such as coating or laminating various materials on at least one side of the film to form green sheets. When the resin layer is only provided on one side, it is preferable to coat or laminate various materials on the film side opposite to the side where the resin layer is provided (the opposite side), but coating or laminating can also be done on the side of the film where the resin layer is provided. It should be noted that in polyester films for sheet forming, a release layer or similar material can be appropriately provided on the film side opposite to the side where the resin layer is provided.

[0355] <<<Other Methods of Laminating Polyester Films>>>

[0356] Other configurations of this laminated polyester film include the following.

[0357] A laminated polyester film comprising a polyester film and a resin layer formed of a resin composition, said resin layer being formed on at least one side of the aforementioned polyester film.

[0358] The aforementioned resin layer has an uneven structure.

[0359] The aforementioned resin composition comprises two or more resins.

[0360] When at least two of the aforementioned two or more resins are designated as resin 1 and resin 2, they satisfy the following relationship (1-2-1).

[0361] HSP distance = {4×(δd1-δd2)} 2 +(δp1-δp2)2 +(δh1-δh2) 2} 0.5 ≥5.0···(1-2-1)

[0362] (Where, δd1, δp1, and δh1 represent the δd, δp, and δh of the first resin in the Hansen solubility parameters [δd, δp, δh], respectively, and δd2, δp2, and δh2 represent the δd, δp, and δh of the second resin in the Hansen solubility parameters [δd, δp, δh]. It should be noted that δp1 is assumed to be ≤ δp2.)

[0363] That is, as another method, the resin layer is as follows: the resin composition used to form the resin layer includes two or more resins, and at least two of the two or more resins include resins that satisfy the following formula (1-2-1) when one is designated as the first resin and the other as the second resin.

[0364] HSP distance = {4×(δd1-δd2)} 2 +(δp1-δp2) 2 +(δh1-δh2) 2} 0.5 ≥5.0···(1-2-1)

[0365] Here, δd1, δp1, and δh1 represent the δd, δp, and δh of the first resin mentioned above in the Hansen solubility parameters [δd, δp, δh], and δd2, δp2, and δh2 represent the δd, δp, and δh of the second resin mentioned above, respectively.

[0366] It should be noted that, regarding the aforementioned first resin and the aforementioned second resin, the resin with the smaller value of the polarity term δp is designated as the first resin, and the resin with the larger value of the polarity term δp is designated as the second resin. That is, δp1 ≤ δp2. Where the polarity term δp values ​​of the two resins are the same, the resin with the smaller value of the hydrogen bonding term δh is designated as the first resin. Where the hydrogen bonding term δh values ​​are also further the same, the resin with the smaller value of the dispersion term δd is designated as the first resin.

[0367] There are no particular limitations on the two or more resins contained in the above resin composition. When selecting two resins based on all the resins contained in the resin composition, at least one of the conceived combinations of two resins must satisfy the relationship of the above formula (1-2-1).

[0368] For example, if the composition contains only three types of resins: resin A, resin B, and resin C, then when selecting two types of resins, the possible combinations are resin A and resin B, resin B and resin C, and resin C and resin A. Therefore, the above means that as long as one or more of these three types satisfy the relationship in equation (1-2-1) above, it is acceptable.

[0369] In other words, as long as the combination of the two resins with the greatest HSP distance among the above three types (the farthest distance between the two resins) satisfies the relationship of the above formula (1-2-1), it is acceptable.

[0370] As described above, as long as one combination satisfies the relationship in equation (1-2-1), phase separation will occur between the compositions of two resins with different compatibility that satisfy the relationship, forming an uneven structure. That is, even if there is a combination of resins that does not satisfy the relationship in equation (1-2-1), the desired uneven structure can still be obtained.

[0371] The total content of the two or more resins, based on non-volatile components, is preferably 50% by mass or more. More preferably, it is 60% by mass or more, and even more preferably 65% ​​by mass or more. If the total content is within the aforementioned range, the effect based on phase separation can be fully utilized, and the desired fine textured structure can be easily obtained. It should be noted that the upper limit of the total content of the two or more resins is not particularly limited, and it is acceptable to be 100% by mass or less.

[0372] It should be noted that there are no particular limitations on the two or more types of resins mentioned above, and the resins exemplified as "first resin" and "second resin" in the following description can be listed as preferred resins.

[0373] (((First Resin)))

[0374] From the viewpoint of forming a fine, uneven structure based on phase separation, the polarity term δp1 of the first resin in the aforementioned two resins is preferably 9.0 MPa. 0.5 Hereinafter, 8.0 MPa is preferred. 0.5 Hereinafter, 7.0 MPa is further preferred. 0.5 Below. If the value of the polarity term δp1 is within the aforementioned range, the polarity of the first resin can be reduced, making it easier to satisfy the relationship in equation (1-2-1) above, and consequently, easier to form the desired uneven structure. The value of the polarity term δp1 is not particularly limited, but is preferably 1.0 MPa. 0.5 The above, and more preferably 2.0 MPa 0.5 above.

[0375] Furthermore, the hydrogen bonding term δh1 of the first resin in the aforementioned two resins is preferably 15.0 MPa. 0.5 The following, or more preferably, is 12.0 MPa0.5 The following, and more preferably, is 9.0 MPa. 0.5 Hereinafter, the dispersion term δd1 is not particularly limited, but is preferably 6.0 MPa. 0.5 The above, and more preferably 8.0 MPa 0.5 The above, and more preferably 10.0 MPa 0.5 The above. If the values ​​of the hydrogen bonding term δh1 and / or the dispersion term δd1 are within the range described above, then the relationship of equation (1-2-1) above can be easily satisfied.

[0376] It should be noted that when there are two or more first resins in this composition that satisfy the relationship of the above formula (1-2-1), at least one of the first resins needs to have the value of the above polarity term δp1, but it is also possible that all the first resins have the value of the above polarity term δp1. The same applies to the hydrogen bonding term δh1 and the dispersion term δd1.

[0377] In this composition, the content of the first resin satisfying the relationship of formula (1-2-1) is preferably 5 to 90% by mass, more preferably 15 to 85% by mass, and even more preferably 35 to 80% by mass, based on its proportion of all non-volatile components in the composition. By setting this content to 5% by mass or more, a textured structure based on phase separation can be sufficiently formed. Furthermore, by setting this content to 90% by mass or less, the content of other resins can be ensured, and the textured structure forming performance based on phase separation can be appropriately adjusted. It should be noted that when there are two or more first resins satisfying the relationship of formula (1-2-1) in this invention, the above-mentioned content refers to their total content.

[0378] From the viewpoint of low polarity term δp1 and hydrogen bonding term δh1, which enables the effective formation of an uneven structure, the aforementioned release agent is preferably used as the first resin. However, substances other than the release agent can also be used as the first resin; for example, the aforementioned crosslinking agent can be used as the first resin. For example, if the aforementioned adhesive is used as the second resin among the two resins mentioned above, the crosslinking agent can be used as the first resin for that adhesive.

[0379] (((Second Resin)))

[0380] From the viewpoint that it also helps to form a fine, uneven structure based on phase separation, thereby improving the coatability when the composition is made into a coating liquid, the hydrogen bonding term δh2 of the second resin in the aforementioned two resins is preferably 8.0 MPa. 0.5 The above, and more preferably 10.0 MPa 0.5 The above, and more preferably 12.0 MPa 0.5The above applies. If the value of the hydrogen bond term δh2 is within the aforementioned range, the hydrophilicity of the second resin can be improved, thus improving its coatability. Furthermore, the relationship in equation (1-2-1) above is easily satisfied, resulting in the easy formation of the desired uneven structure.

[0381] The hydrogen bonding term δh2 of the second resin in the aforementioned two resins is preferably 25.0 MPa. 0.5 The following, or more preferably, is 23.0 MPa 0.5 The following, and more preferably, is 20.3 MPa. 0.5 The following method is used to prevent the hydrophilicity from becoming too high by keeping the value of the hydrogen bond term δh2 below a certain level. This prevents the coating from absorbing water and softening, reducing its surface roughness, and improving its sliding properties.

[0382] Furthermore, the polarity term δp2 of the second resin among the aforementioned two resins is preferably 7.0 MPa. 0.5 The above, and more preferably 8.0 MPa 0.5 The above, and more preferably 9.0 MPa 0.5 The dispersion term δd2 is not particularly limited, but is preferably 6.0 MPa. 0.5 The above, and more preferably 8.0 MPa 0.5 The above, and more preferably 10.0 MPa 0.5 The above. If the values ​​of the hydrogen bonding term δh2 and / or the dispersion term δd2 are within the range described above, then the relationship of equation (1-2-1) above is easily satisfied.

[0383] It should be noted that in this composition, when there are two or more second resins satisfying the relationship of the above formula (1-2-1), at least one of the second resins needs to have the value of the hydrogen bonding term δh2, but it is also possible that all the second resins have the value of the hydrogen bonding term δh2. The same applies to the polarity term δp2 and the dispersion term δd2.

[0384] The content of the second resin satisfying the relationship of formula (1-2-1) in this composition is preferably 10-90% by mass, more preferably 15-85% by mass, and even more preferably 20-65% by mass, based on its proportion of all non-volatile components in the composition. By setting this content to 10% by mass or more, it is possible to balance the formation of the uneven structure based on phase separation and the improvement of the coatability when the composition is made into a coating liquid. In addition, by setting this content to 90% by mass or less, the content of the first resin can be ensured, and the uneven formation performance based on phase separation can be appropriately adjusted. It should be noted that when there are two or more types of the second resin satisfying the relationship of formula (1-2-1) in this invention, the above content refers to their total content.

[0385] The aforementioned second resin is not particularly limited, but it is preferable to have film-forming ability. More specifically, examples of the aforementioned second resin include the aforementioned adhesive resin, crosslinking agent, etc.

[0386] (((The resin of component 3)))

[0387] This resin layer must contain at least two types of resin. From the viewpoint of easier adjustment of the uneven shape, and thus control over the adhesion to the polyester film and the coating strength, it is preferable to contain three or more types of resin. In this case, it is preferable to consider not only the furthest distance between the aforementioned two resins, but also the distance to the resin of the third component.

[0388] As a more preferred embodiment, the polarity term δp1 of the first resin among the two resins mentioned above is 9.0 MPa. 0.5 Based on the following, the two or more resins mentioned above include resins with an HSP distance of 6.0 or more relative to the first resin, but do not include resins with an HSP distance of 5.5 or less. In this case, the HSP distance is calculated using the relationship determined by the above formula (1-2-1).

[0389] In other words, other resins are preferably 9.0 MPa relative to the polarity term δp1. 0.5 The nearest distance of the first resin (low δp resin) is greater than 5.5, and the farthest distance of the other resins relative to the low δp resin is greater than 6.0.

[0390] The above conditions are preferably met when the resin composition contains three or more resins, but the above conditions can also be met when the resin composition contains only two resins.

[0391] If the above conditions can be met, fine uneven structures can be more effectively exhibited through phase separation. From this point of view, it is more preferable to include a resin with an HSP distance of 7.0 or more, and even more preferable to include a resin with an HSP distance of 8.0 or more. Furthermore, it is more preferable not to include a resin with an HSP distance of 6.0 or less, and even more preferable not to include a resin with an HSP distance of 7.0 or less.

[0392] The above two or more resins preferably contain a release agent as the first resin.

[0393] Furthermore, as a more preferred embodiment, it can be illustrated that the first resin of the aforementioned two resins is a mold release agent, and the aforementioned two or more resins include a resin with an HSP distance of 6.0 or more relative to the mold release agent, but do not include a resin with an HSP distance of 5.5 or less. In this case, the HSP distance is calculated using the relationship determined by the above formula (1-2-1).

[0394] In other words, it is preferred that the closest distance between other resins and the release agent is greater than 5.5, and the farthest distance between other resins and the release agent is greater than 6.0.

[0395] If the above conditions can be met, a fine, uneven structure can be more effectively exhibited through phase separation. From this point of view, it is more preferable to include a resin having an HSP distance of 7.0 or more relative to the release agent, and even more preferable to include a resin having an HSP distance of 8.0 or more. Furthermore, it is more preferable to exclude resins having an HSP distance of 6.0 or less relative to the release agent, and even more preferable to exclude resins having an HSP distance of 7.0 or less.

[0396] <<<Laminated polyester film with antistatic properties>>>

[0397] Polyester films are prone to static electricity generation due to contact friction and peeling during processing and use, especially when the surface is smooth, which increases the likelihood of static electricity buildup and the adhesion of dust and small debris. Therefore, there are concerns about processing defects caused by contamination and foreign matter ingress during processing. Furthermore, uneven processing of secondary layers can occur due to the film becoming charged during processing. Therefore, for applications requiring the prevention of foreign matter ingress and static charge, methods such as coating the polyester film surface with a laminated antistatic agent have been proposed (e.g., Japanese Patent Application Publication No. 7-26223).

[0398] The same problem exists in the laminated polyester film of the present invention. It is desirable to have a laminated polyester film that can form a fine uneven structure even in a film, has excellent processability when the film is rolled into a roll, and can also suppress the charge of the film.

[0399] Specifically, it is a laminated polyester film having the following composition.

[0400] That is, a laminated polyester film comprising a polyester film and a resin layer (hereinafter also referred to as "resin layer (X)") formed of a resin composition (hereinafter also referred to as "resin composition (X)"), said resin layer being formed on at least one side of the aforementioned polyester film, said laminated polyester film satisfying all of the following conditions (a) to (c).

[0401] (a) The surface resistivity of the aforementioned resin layer is 1×10⁻⁶. 13 Below Ω / □.

[0402] (b) The aforementioned resin composition comprises the following compounds (Aa) and (B).

[0403] (Aa) Antistatic agent

[0404] (B) Selected from one or more of the group consisting of adhesive resins and crosslinking agents

[0405] (c) The bearing length ratio (Rmr(80)) of the roughness curve at the cut level of 80% of the aforementioned resin layer surface when measured by scanning probe microscope is 85% or less.

[0406] The resin layer (X) in the laminated polyester film is formed from the resin composition (x) as described above, and has a surface resistivity of 1×10⁻⁶. 13 Below Ω / □. Furthermore, the resin layer (X) is formed from the resin composition (x), thereby having an uneven structure.

[0407] The uneven structure of the resin layer (X) is a fine shape formed by phase separation. The unevenness based on phase separation is obtained by the phase separation caused by the composition of resins with different compatibility during processes such as coating, stretching, drying, curing, and heat treatment, thereby forming an uneven structure on the surface. More specifically, it is obtained by forming concave or convex portions through phase separation, thereby forming an uneven structure on the surface.

[0408] It should be noted that its structure can be confirmed by various surface analysis methods, such as atomic force microscopy (scanning probe microscopy).

[0409] Here, "resin" refers to the main component involved in the formation of the coating. More specifically, it includes an antistatic agent as the aforementioned compound (Aa), and one or more compounds selected from the group consisting of adhesive resins and crosslinking agents as compound (B).

[0410] The total content of compounds (Aa) and (B) in the resin composition (x), based on non-volatile components, is preferably 50% by mass or more. More preferably, it is 60% by mass or more, and even more preferably 65% ​​by mass or more. If the total content is within the range described above, the effect based on phase separation can be fully utilized, and the desired fine textured structure can be easily obtained. It should be noted that the upper limit of the total content of compounds (Aa) and (B) is not particularly limited, as long as it is 100% by mass or less.

[0411] (((compound(Aa))))

[0412] The resin composition (x) contains an antistatic agent (compound (Aa)). There are no particular limitations on the aforementioned antistatic agent (Aa), and conventionally known compounds can be used.

[0413] The resin layer (X) as described above has a surface resistivity of 1×10⁻⁶. 13 For resistance values ​​below Ω / □, the resin composition (x) contains compound (Aa), which reduces the surface resistivity. Furthermore, it is speculated that the antistatic agent composition (Aa) may contain a specific compound (B) described later, which can form fine irregularities.

[0414] Examples of compounds (Aa) include compounds containing ammonium groups, polyether compounds, sulfonic acid compounds, betaine compounds, and other ionicly conductive compounds, as well as compounds with π-electron conjugation systems such as polyacetylene, polyphenylene, polyaniline, polypyrrole, polyisothioindene, and polythiophene. Among these, ionicly conductive compounds are preferred, and compounds containing ammonium groups are particularly preferred. In the resin composition (x), the antistatic agent may be used alone or in combination of two or more.

[0415] It should be noted that conductive coatings containing π-electron conjugated systems, such as polythiophene and polyaniline, are generally more expensive than conductive coatings containing ionicly conductive compounds. Therefore, from a manufacturing cost perspective, it is also appropriate to use antistatic agents containing ionicly conductive compounds.

[0416] Furthermore, from the viewpoints of film-forming properties, preventing transfer to the opposite side of the film, and process contamination, antistatic agents are preferably polymeric compounds with a number average molecular weight of 1000 or higher.

[0417] (Compounds containing ammonium groups)

[0418] The aforementioned ammonium-containing compounds refer to compounds that have an ammonium group within their molecules, and are preferably polymers containing an ammonium group. For example, polymers containing monomers having an ammonium group and an unsaturated double bond can be used as components.

[0419] As specific examples of this polymer, polymers having the constituent elements shown in formula (2-1-1) or formula (2-1-2) as repeating units can be cited. Homopolymers, copolymers, and other components can also be copolymerized. From the viewpoint of more effectively forming an uneven structure through compatibility with other materials and the antistatic properties of the resulting resin layer (X), polymers having the constituent elements shown in formula (2-1-2) as repeating units are preferred.

[0420]

[0421] In the above equation (2-1-1), R 2 For -O- or -NH-, R 3 R is an alkylene group, or any other structure that enables the structure of formula (2-1-1) to hold. 1 R 4 R 5 R 6 These are hydrogen atoms, alkyl groups, phenyl groups, etc., and these alkyl and phenyl groups can be substituted by the groups shown below. Substitutable groups include, for example, hydroxyl, amide, ester, alkoxy, phenoxy, naphthoxy, thioalkoxy, thiophenoxy, cycloalkyl, trialkylammonium alkyl, cyano, halogen, etc.

[0422]

[0423] In the above formula (2-1-2), R 1 R 2 Each group can be independently composed of hydrogen atoms, alkyl groups, phenyl groups, etc., and these alkyl and phenyl groups can be substituted with groups as shown below. Substitutable groups include, for example, hydroxyl, amide, ester, alkoxy, phenoxy, naphthoxy, thioalkoxy, thiophenoxy, cycloalkyl, trialkylammonium alkyl, cyano, halogen, etc. Additionally, R... 1 and R 2 They can be chemically bonded; for example, -(CH2) can be listed. m -(m=an integer from 2 to 5), -CH(CH3)CH(CH3)-, -CH=CH-CH=CH-, -CH=CH-CH=N-, -CH=CH-N=C-, -CH2OCH2-, -(CH2)2O(CH2)2-, etc.

[0424] From the viewpoint of improving film-forming properties, improving adhesion to polyester film substrates, preventing coating peeling, and preventing component transfer to the back side, polymers having the constituent elements shown in formula (2-1-1) or formula (2-1-2) as repeating units can also be copolymerized with other repeating units.

[0425] From the viewpoint of forming a more efficient concave-convex structure, it is preferable to use homopolymers with the constituent elements shown in formula (2-1-1) or formula (2-1-2) above as repeating units.

[0426] Other repeating units include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, alkyl (meth)acrylates, and acrylamides such as N-hydroxymethylacrylamide.

[0427] In the above equations (2-1-1) and (2-1-2), X - Appropriate selections may be made within the scope of the invention without prejudice to its spirit. Examples include halide ions, sulfonate ions, phosphate ions, nitrate ions, alkyl sulfonate ions, and carboxylate ions.

[0428] Compounds containing the constituent elements shown in formula (2-1-2) and other ammonium salt groups within a polymer backbone exhibit excellent heat resistance and are therefore preferred.

[0429] Furthermore, the polymer formed by copolymerizing the constituent elements shown in formulas (2-1-1) to (2-1-2) with (meth)acrylate containing polyethylene glycol has a soft structure, and a resin layer (X) with excellent uniformity can be obtained during coating and stretching, which is therefore preferred.

[0430] Alternatively, a resin layer (X) with excellent uniformity can also be obtained by coating a coating solution containing a (meth)acrylate polymer containing polyethylene glycol.

[0431] Furthermore, the number average molecular weight of the ammonium-containing compounds is typically 1,000 to 500,000, preferably 2,000 to 350,000, and more preferably 5,000 to 200,000. By setting the molecular weight to 1,000 or higher, it is possible to prevent the coating strength from weakening and to easily achieve good heat resistance stability. In addition, by setting the molecular weight to 500,000 or lower, it is possible to prevent the viscosity of the coating liquid from increasing, and to easily achieve good processability and coatability.

[0432] The content of compound (Aa) in the resin composition (x), based on its proportion to all non-volatile components in the resin composition (x), is preferably in the range of 5 to 90% by mass, more preferably 10 to 85% by mass, and even more preferably 20 to 75% by mass. By setting this content to 5% by mass or more, not only can a sufficiently textured structure based on phase separation be formed, but sufficient antistatic properties can also be imparted. Furthermore, by setting this content to 90% by mass or less, the content of other resins can be ensured, and the texture-forming properties based on phase separation can be appropriately adjusted.

[0433] (((Compound(B))))

[0434] The resin composition (x) contains one or more compounds (B) selected from adhesive resins and crosslinking agents.

[0435] The aforementioned compound (B) can also help to form a fine, uneven structure through phase separation, thereby improving the coatability of the resin composition (x) when it is made into a coating liquid.

[0436] ((adhesive resin))

[0437] The aforementioned adhesive resin selected as compound (B) is defined, according to the "Polymer Safety Evaluation Procedure" (November 1941, sponsored by the Chemical Substances Council), as a polymer compound with a number-average molecular weight (Mn) of 1000 or higher as determined by gel permeation chromatography (GPC), and possessing film-forming properties. It should be noted that the aforementioned adhesive resin does not include the aforementioned antistatic agent or the crosslinking agent described later.

[0438] There are no particular limitations on the adhesive resin used; conventionally known adhesive resins can be used. Examples include release agents, (meth)acrylic resins, polyvinyl alcohol, polyester resins, and polyurethane resins. Among these, a release agent is preferred from the viewpoint of facilitating phase separation from the (Aa) antistatic agent and achieving excellent formation of a fine textured structure. Furthermore, from the viewpoint of maintaining the textured formation performance based on phase separation and film formation, (meth)acrylic resins and polyvinyl alcohol are preferred, and at least one of (meth)acrylic resins and polyvinyl alcohol is more preferred. That is, the adhesive resin preferably includes one or more resins selected from the group consisting of release agents, (meth)acrylic resins, and polyvinyl alcohol. In the resin composition (X), one type of adhesive resin can be used alone, or two or more types can be used in combination.

[0439] It should be noted that the crosslinking agent selected as the aforementioned compound (B) can be the same substance as the crosslinking agent described for the aforementioned resin composition.

[0440] (((Specially Preferred Method)))

[0441] The compounds (Aa) and (B) contained in the resin composition (x) are particularly preferred to be (a) an antistatic agent and a release agent, (b) an antistatic agent and a binder resin other than a release agent, and (c) a combination of an antistatic agent, a release agent and a crosslinking agent, especially the combination of (c).

[0442] Regarding the content of each component in the combination of (c) above, when the content of the antistatic agent as compound (Aa) is set to 100 parts by mass, the ratio of the release agent and crosslinking agent as compound (B) (antistatic agent / release agent / crosslinking agent) is preferably 100 / (10-500) / (10-500), and more preferably 100 / (20-300) / (20-250).

[0443] <<<Physical Properties of Laminated Polyester Films with Antistatic Properties>>>

[0444] The bearing length ratio (Rmr(80)) of the roughness curve of the resin layer surface of the laminated polyester film with antistatic properties at a cut level of 80% is less than 85%.

[0445] The support length ratio (Rmr(c)) is one of the line roughness parameters (JIS B 0601), which represents the ratio of the support length ML(c) of the profile curve element cut at the horizontal level c (height % or μm) to the evaluation length Ln, and is calculated by the following equation (2-1-3).

[0446]

[0447] Here, the inventors believe that the support length ratio (Rmr(80)) is effective as an indicator of the concave-convex distribution of the concave-convex structure. For example, when the concave distribution is large, the value of the support length ratio (Rmr(80)) becomes smaller, and when the convex distribution is large, the value of the support length ratio (Rmr(80)) becomes larger. The smaller the support length ratio (Rmr(80)), the larger the gap formed between the films when the film is wound into a roll, the easier it is to expel air, and the better the winding performance.

[0448] The bearing length ratio (Rmr(80)) of the roughness curve at 80% of the cutting level is, as described above, 85% or less, preferably 70% or less, more preferably 58% or less, and particularly preferably 50% or less. The lower limit is not particularly limited, but is approximately 1%, preferably 4%, and more preferably 6%.

[0449] The aforementioned support length ratio (Rmr(80)) can be adjusted by the composition, content, etc. of the resin composition (X).

[0450] Furthermore, the bearing length ratio (Rmr(50)) of the roughness curve at a cut level of 50% of the resin layer surface is 60% or less, more preferably 40% or less, and even more preferably 25% or less. The lower limit is not particularly limited, but is approximately 1%, preferably 3%, and more preferably 5%.

[0451] Here, the inventors believe that it is effective to consider the support length ratio (Rmr(80)) as an indicator of the unevenness distribution of the uneven structure, in addition to considering the support length ratio (Rmr(80)). For example, even with the same support length ratio (Rmr(80)), it can be said that a smaller support length ratio (Rmr(50)) results in a finer convex shape, and a larger support length ratio (Rmr(50)) results in a coarser convex shape. Therefore, the smaller the support length ratio (Rmr(50)), the finer the unevenness, the larger the gap formed between the films when the film is wound into a roll, the easier it is to expel air, and the better the winding performance.

[0452] The aforementioned support length ratio (Rmr(50)) can also be adjusted by the composition, content, etc. of the resin composition (X).

[0453] Furthermore, the arithmetic mean roughness (Ra) of the resin layer surface is preferably 10 nm or more, more preferably 15 nm or more, and even more preferably 20 nm or more. There is no particular upper limit, but 600 nm is preferred, more preferably 400 nm, and even more preferably 200 nm. If the arithmetic mean roughness (Ra) is 10 nm or more, the resin layer (X) can be said to have a fine uneven structure, resulting in good processability of the laminated polyester film. Conversely, if the arithmetic mean roughness (Ra) is 600 nm or less, the uneven structure of the resin layer (X) can be considered to be a sufficiently fine shape.

[0454] Arithmetic mean roughness (Ra) is one of the line roughness parameters (JIS B 0601), representing the average value of the average height difference from the mean surface.

[0455] That is, extract a portion of the reference length L, set the average line of the extracted portion as the x-axis, set the direction of the vertical magnification as the y-axis, and use y=Z(x) to represent the roughness curve, which is then calculated according to the following formula (2-1-4).

[0456]

[0457] Furthermore, the ten-point average roughness (Rzjis) of the resin layer surface is preferably 28 nm or more, more preferably 40 nm or more, even more preferably 60 nm or more, and particularly preferably 120 nm or more. There is no particular upper limit, but 800 nm is preferred, more preferably 600 nm, and even more preferably 500 nm. If the ten-point average roughness (Rzjis) is 28 nm or more, the resin layer (X) can be said to have a sufficiently uneven structure. Conversely, if the ten-point average roughness (Rzjis) is 800 nm or less, the uneven structure of the resin layer (X) can be considered to be a sufficiently fine shape.

[0458] The ten-point average roughness (Rzjis) is one of the line roughness parameters (JIS B 0601). It represents the sum of the average of the maximum peak height (Zp) to the fifth peak of the profile curve and the average of the deepest valley depth (Zv) to the fifth valley in the reference length L. It is calculated according to the following formula (2-1-5).

[0459]

[0460] The arithmetic mean roughness (Ra) and ten-point mean roughness (Rzjis) mentioned above can be adjusted by the composition, content, etc. of the resin composition (X).

[0461] It should be noted that the bearing length ratio (Rmr(80)), bearing length ratio (Rmr(50)), arithmetic mean roughness (Ra), and ten-point mean roughness (Rzjis) of the resin layer surface were measured using an atomic force microscope (scanning probe microscope) according to the method described in the examples. Measurements based on an atomic force microscope (scanning probe microscope) can capture finer surface structures, resulting in values ​​that strongly reflect the effects of the resin layer (X).

[0462] In a laminated polyester film with antistatic properties, the surface resistivity of the resin layer is 1×10⁻⁶. 13 Ω / □ or less, preferably 5×10 11 Ω / □ or less, more preferably 5×10 10 Below Ω / □. It should be noted that there is no particular limitation on the lower limit of the surface resistivity value, but considering the cost required to manufacture this laminated polyester film, a value of 1×10⁻⁶ is preferred. 4 Ω / □ and above.

[0463] When the laminated polyester film is rolled into a roll, peeling static electricity is generated when it is unwound for secondary processing and peeled off from the side opposite to the resin layer. Additionally, static electricity is generated between the roller and the resin layer and the opposite side during film conveying. This static electricity can lead to the adhesion of foreign matter and uneven processing of the secondary processing layer. Therefore, it is important to prevent static electricity or accelerate its decay by reducing the surface resistivity.

[0464] If the surface resistance value is within the specified range, the static electricity on the film surface can be kept low, which can suppress the adhesion of foreign matter to the laminated polyester film and the impact on the secondary processing layer.

[0465] The surface resistance value can be adjusted according to the type and content of the antistatic agent (Aa) in the resin composition (x), the type of compound (B) in the composition, and the amount of non-volatile components of the resin layer (X) coated.

[0466] Laminated polyester films with antistatic properties can be used for a variety of purposes to improve operability and suppress static electricity on the film surface, and their applications are not particularly limited.

[0467] It should be noted that the above surface resistance values ​​can be measured using the methods described below.

[0468] (Methods for measuring surface resistivity)

[0469] The measurement can be performed using a high-resistivity resistivity meter (Mitsubishi Chemical Analysis Technology Co., Ltd., Hirestar UX MCP-HT 800) and a measurement probe (UR-100). As for measurement conditions, for example, after fully conditioned the laminated polyester film (sample) in a measurement atmosphere of 23°C and 50% RH, the surface resistance (Ω / □) of the resin layer is measured after 1 minute under an applied voltage of 100V.

[0470] <<<Other Methods for Laminating Polyester Films with Antistatic Properties>>>

[0471] There are other methods for producing laminated polyester films with antistatic properties. Specifically:

[0472] A laminated polyester film comprising a polyester film and a resin layer formed of a resin composition, said resin layer being formed on at least one side of the aforementioned polyester film.

[0473] The surface resistivity of the aforementioned resin layer is 1×10⁻⁶. 13 Below Ω / □

[0474] The aforementioned resin composition comprises two or more resins.

[0475] When at least two of the aforementioned two or more resins are designated as resin 1 and resin 2, they satisfy the following relationship (2-2-1).

[0476] HSP distance = {4×(δd1-δd2)} 2 +(δp1-δp2) 2 +(δh1-δh2) 2} 0.5 ≥5.0···(2-2-1)

[0477] (Where, δd1, δp1, and δh1 represent the δd, δp, and δh of the first resin in the Hansen solubility parameters [δd, δp, δh], respectively, and δd2, δp2, and δh2 represent the δd, δp, and δh of the second resin in the Hansen solubility parameters [δd, δp, δh]. It should be noted that δh1 is assumed to be ≥ δh2.)

[0478] It should be noted that, regarding the HSP distance as described above, in this method, for the aforementioned first resin and the aforementioned second resin, the resin with the larger value of the hydrogen bonding term δh is designated as the first resin, and the resin with the smaller value of the hydrogen bonding term δh is designated as the second resin. That is, δh1 ≥ δh2 is assumed. Wherein, if the hydrogen bonding term δh values ​​of the two resins are the same, the resin with the larger value of the polarity term δp is designated as the first resin; if the polarity term δp values ​​are also further the same, the resin with the smaller value of the dispersion term δd is designated as the first resin.

[0479] By employing this method, it is possible to provide laminated polyester films that can form fine textured structures even in thin films and suppress the charge of the films.

[0480] In the above method, the surface resistivity of the resin layer of the laminated polyester film is 1×10⁻⁶. 13 Ω / □ or less, preferably 5×10 11 Ω / □ or less, more preferably 5×10 10 Below Ω / □. It should be noted that there is no particular limitation on the lower limit of the surface resistivity value, but considering the cost required to manufacture the laminated polyester film, 1×10⁻⁶ is preferred. 4 Ω / □ and above.

[0481] If the surface resistance value is within the specified range, the static electricity on the film surface can be kept low, which can suppress the adhesion of foreign matter to the laminated polyester film and the impact on the secondary processing layer.

[0482] (((First Resin)))

[0483] From the viewpoint of facilitating the formation of a fine, uneven structure based on phase separation and imparting antistatic properties, the hydrogen bonding term δh1 of the first resin in the aforementioned two resins is preferably 8.0 MPa. 0.5 The above, and more preferably 13.0 MPa 0.5 The above, and more preferably, is 16.0 MPa 0.5 The above applies. If the value of the hydrogen bond term δh1 is within the aforementioned range, the hydrophilicity of the first resin can be improved, making it easier to satisfy the relationship in equation (2-2-1) and thus easily forming the desired uneven structure. Furthermore, the high hydrophilicity also readily imparts antistatic properties. The upper limit of the hydrogen bond term δh1 is not particularly limited, but is preferably 25.0 MPa. 0.5 The following, or more preferably, is 23.0 MPa 0.5 the following.

[0484] Furthermore, the polarity term δp1 of the first resin in the aforementioned two resins is preferably 4.0 MPa. 0.5 The above, and more preferably 7.0 MPa 0.5 The above, and more preferably 10.0 MPa 0.5 The dispersion term δd1 is not particularly limited, but is preferably 6.0 MPa. 0.5 The above, and more preferably 8.0 MPa 0.5 The above, and more preferably 10.0 MPa 0.5 The above. If the values ​​of the polarity term δp1 and / or the dispersion term δd1 are within the range described above, then the relationship of equation (2-2-1) above is easily satisfied.

[0485] It should be noted that when there are two or more first resins in the resin composition (X) that satisfy the relationship of the above formula (2-2-1), at least one of the first resins needs to have the value of the hydrogen bonding term δh1, but it is also possible that all the first resins have the value of the hydrogen bonding term δh1. The same applies to the polarity term δp1 and the dispersion term δd1.

[0486] In the resin composition (x), the content of the first resin satisfying the relationship of formula (2-2-1) above is preferably 5 to 90% by mass, more preferably 10 to 85% by mass, and even more preferably 20 to 75% by mass, based on its proportion of all non-volatile components in the resin composition (x). By setting this content to 5% by mass or more, not only can a sufficiently formed uneven structure based on phase separation be formed, but sufficient antistatic properties can also be imparted. In addition, by setting this content to 90% by mass or less, the content of other resins can be ensured, and the uneven formation performance based on phase separation can be appropriately adjusted. It should be noted that when there are two or more first resins satisfying the relationship of formula (2-2-1) above, the above content refers to their total content.

[0487] From the viewpoints of high hydrogen bonding term δh1, high polarity term δp1, the ability to effectively form an uneven structure, and the ability to impart antistatic properties, the antistatic agent described later is preferably used as the first resin. However, resins other than antistatic agents may also be used as the first resin; for example, the binder or crosslinking agent described later may be used as the first resin.

[0488] (((Second Resin)))

[0489] From the viewpoint of facilitating the formation of a fine, uneven structure based on phase separation, the hydrogen bonding term δh2 of the second resin in the aforementioned two resins is preferably 14.0 MPa. 0.5 The following, or more preferably, is 10.0 MPa 0.5 The following, and more preferably, is 8.0 MPa. 0.5 If the value of the hydrogen bond term δh2 is within the specified range, the hydrophilicity of the aforementioned second resin can be reduced, making it easier to satisfy the relationship in the above formula (2-2-1), and as a result, the desired uneven structure can be easily formed.

[0490] The hydrogen bonding term δh2 of the second resin in the aforementioned two resins is preferably 1.0 MPa. 0.5 The above, and more preferably 2.0 MPa 0.5 The above, and more preferably 3.0 MPa 0.5 above.

[0491] Furthermore, the polarity term δp2 of the second resin among the aforementioned two resins is preferably 16.0 MPa. 0.5 The following, or more preferably, is 10.0 MPa 0.5The following, and more preferably, is 7.0 MPa. 0.5 Hereinafter, the dispersion term δd2 is not particularly limited, but is preferably 6.0 MPa. 0.5 The above, and more preferably 8.0 MPa 0.5 The above, and more preferably 10.0 MPa 0.5 The above. If the values ​​of the polarity term δp2 and / or the dispersion term δd2 are within the range described above, then the relationship of equation (2-2-1) above is easily satisfied.

[0492] It should be noted that when there are two or more second resins in the resin composition (X) that satisfy the relationship of the above formula (2-2-1), at least one of the second resins needs to have the value of the hydrogen bonding term δh2, but it is also possible that all the second resins have the value of the hydrogen bonding term δh2. The same applies to the polarity term δp2 and the dispersion term δd2.

[0493] The content of the second resin in the resin composition (x) that satisfies the relationship of formula (2-2-1) above is preferably 10 to 95% by mass, more preferably 15 to 90% by mass, and even more preferably 20 to 80% by mass, based on its proportion of all non-volatile components in the resin composition (x). By setting this content to 10% by mass or more, it is possible to facilitate the formation of an uneven structure based on phase separation. Furthermore, by setting this content to 95% by mass or less, it is possible to ensure the content of the first resin, obtain the desired surface resistivity value, and moderately adjust the uneven formation performance based on phase separation. It should be noted that when there are two or more types of the second resin that satisfy the relationship of formula (2-2-1) above, the above content refers to their total content.

[0494] The aforementioned second resin is not particularly limited, but from the viewpoint of effectively forming an uneven structure, a release agent is preferred. Furthermore, from the viewpoint of having film-forming ability, an adhesive resin and a crosslinking agent are preferred. More specifically, the aforementioned second resin can include, as described later, the release agent, adhesive resin, and crosslinking agent.

[0495] (((The resin of component 3)))

[0496] The resin layer (X) must contain at least two types of resin. From the viewpoint of making it easier to adjust the uneven shape and thus control the adhesion to the polyester film and the coating strength, it is preferable to contain three or more types of resin. In this case, it is preferable to consider not only the furthest distance between the aforementioned two resins, but also the distance to the resin of the third component.

[0497] As a preferred embodiment, when the resin comprises three or more resins, preferably two or more of the resins do not include resins with an HSP distance of 3.0 or less, and more preferably do not include resins with an HSP distance of 4.0 or less. In this case, the HSP distance is calculated using the relationship determined by the above formula (2-2-1).

[0498] If the above conditions are met, the fine uneven structure can be more effectively manifested through phase separation. Therefore, the result is a good air leakage index, making it easier to remove air mixed in during the winding of the laminated polyester film and preventing defects in the roll appearance such as wrinkles and uneven end faces. It should be noted that the air leakage index will be explained in detail later.

[0499] The surface resistivity value can be adjusted by the type and content of the antistatic agent in the resin composition (x), the HSP distance between the antistatic agent and other resins in the composition, and the amount of non-volatile components of the resin layer (X) coated.

[0500] <<<Release Film>>>

[0501] The laminated polyester film of the present invention can also be made into a release film having a release layer on the side of the polyester film opposite to the resin layer. Specific configurations are described below.

[0502] A release film comprising a polyester film and a resin layer formed of a resin composition, the resin layer being formed on one surface of the polyester film and a release layer being provided on the other surface of the polyester film, the release film satisfying all of the following conditions (1) and (2).

[0503] (1) The aforementioned resin composition comprises the following compounds (A) and (B).

[0504] (A) Low polar compounds

[0505] (B) Selected from one or more of the group consisting of adhesive resins and crosslinking agents

[0506] (2) The bearing length ratio (Rmr(80)) of the roughness curve at the cut level of 80% of the aforementioned resin layer surface when measured by scanning probe microscope is 94% or less.

[0507] As described above, the laminated structure of the release film includes a release layer, a polyester film, and a resin layer in sequence.

[0508] Alternatively, a release layer can be formed directly on the polyester film, or other layers can be placed between the polyester film and the release layer.

[0509] Furthermore, a resin layer can be formed directly on the polyester film, or other layers can be provided between the polyester film and the resin layer.

[0510] <<Demolding Layer>>

[0511] The release film has a release layer on the other surface side of the polyester film.

[0512] As described above, the aforementioned release layer is laminated directly onto the polyester film or in between other layers. Examples of other layers include, for instance, an easy-to-adhere coating to improve adhesion to the polyester film, as well as an antistatic layer, an anti-sticking layer, etc.

[0513] <Mold Release Agent Composition>

[0514] The aforementioned release layer is formed from a release agent composition.

[0515] In addition, the release agent composition contains a release agent.

[0516] ((Mold Release Agent))

[0517] There are no particular limitations on the aforementioned release agent; conventionally known release agents can be used. Examples include organosilicon compounds, compounds containing long-chain alkyl groups, waxes, and fluorinated compounds. Among these, at least one of organosilicon compounds and compounds containing long-chain alkyl groups is preferred. In the release agent composition, one type of release agent can be used alone, or two or more types can be used in combination.

[0518] ((organosilicon compounds))

[0519] Organosilicon compounds are compounds that have an organosilicon structure within their molecules; in other words, they are compounds with a main skeleton based on siloxane bonds. Examples of organosilicon compounds or their main skeletons include organopolysiloxanes such as polydimethylsiloxane, acrylic-grafted organosilicon, organosilicon-grafted acrylic, amino-modified organosilicon, perfluoroalkyl-modified organosilicon, and alkyl-modified organosilicon. From the viewpoint of excellent mold release properties, organopolysiloxanes such as polydimethylsiloxane are preferred.

[0520] Preferably, the organosilicon compound has a functional group capable of reacting with the (meth)acrylyl group in the compounds containing (meth)acrylyl groups described later, and particularly preferably is an organosilicon compound containing Si-H groups. The Si-H groups of the organosilicon compound have the property of improving adhesion to the polyester film. From the viewpoint of forming a crosslinked structure with a backbone derived from the organosilicon compound in the release layer, organosilicon compounds having both Si-H groups and alkenyl groups are preferred.

[0521] The molecular weight of the organosilicon compound is not particularly limited. However, from the viewpoint of ensuring good adhesion between the polyester film and the release layer, its number-average molecular weight is preferably 5,000 or more, more preferably 10,000 or more. There is no particular upper limit, but it is generally 1,000,000 or less.

[0522] The number-average molecular weight of organosilicon compounds can be determined, for example, using gel permeation chromatography (GPC) and calculated in the form of polystyrene equivalents.

[0523] In the foregoing, the organosilicon compound used in the release agent composition is preferably a curable organosilicon compound, taking into account heat resistance and staining properties.

[0524] As for the types of curable silicone compounds, any curing reaction type such as addition-curing, condensation-curing, UV-curing, and electron beam-curing can be used. Among these, addition-curing silicone compounds are preferred from the viewpoint of improving the cohesive strength of the coating film.

[0525] Addition-curing organosilicon compounds are organosilicon compounds with unsaturated hydrocarbon and hydrogen groups as functional groups in their structure, which undergo addition curing reactions through the reaction of these functional groups. That is, they are mixtures of organosilicon compounds with Si-H groups and organosilicon compounds containing alkenes, or organosilicon compounds containing Si-H groups and vinyl groups in their molecules.

[0526] From the viewpoint of service life, it is preferable that the unsaturated hydrocarbon group and the hydrogen group do not exist in the same molecule, and it is preferable that the functional groups are contained in different organosilicon molecules and that a mixture of them is used. Therefore, it is preferable to use an organosilicon compound having an unsaturated hydrocarbon group as a functional group mixed with an organosilicon compound having a hydrogen group as a functional group.

[0527] As an example of the aforementioned organosilicon compounds having unsaturated hydrocarbon groups as functional groups, polydimethylsiloxanes containing unsaturated hydrocarbon groups can be cited.

[0528] The unsaturated hydrocarbon group must be present in at least two molecules of the polydimethylsiloxane. Examples of unsaturated hydrocarbon groups include vinyl, propenyl, butenyl, and pentenyl alkenyl groups with 2 to 8 carbon atoms. Among these, vinyl is preferred from the perspective of industrial availability.

[0529] An alkenyl group containing at least two alkenyl groups can contain alkenyl groups with different numbers of carbon atoms.

[0530] Polydimethylsiloxanes containing unsaturated hydrocarbon groups have alkenyl and methyl groups as functional groups that directly bond with silicon atoms, and may also have various other functional groups. Examples of functional groups other than methyl include alkyl groups such as ethyl, propyl, and butyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl and methylphenyl; and alkoxy groups such as hydroxyl, methoxy, and ethoxy. From the viewpoint of adhesion to polyester films, the presence of phenyl and methoxy groups is preferred.

[0531] On the other hand, among the aforementioned organosilicon compounds having hydrogen groups as functional groups, hydrogen-containing polydimethylsiloxanes can be cited. Hydrogen-containing polydimethylsiloxanes refer to polydimethylsiloxanes having hydrogen atoms bonded to silicon atoms. Each molecule needs to contain at least two hydrogen atoms bonded to silicon atoms, and from the viewpoint of curing properties, it is preferable to contain three or more. The hydrogen atoms bonded to silicon can be at the end of the polydimethylsiloxane molecular chain or as side chains.

[0532] Hydrogen-containing polydimethylsiloxanes have hydrogen and methyl groups as functional groups that directly bond with silicon atoms, and can also have various other functional groups. Examples of functional groups other than methyl include alkyl groups such as ethyl, propyl, and butyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl and methylphenyl; and alkoxy groups such as methoxy and ethoxy.

[0533] The polydimethylsiloxane backbone containing unsaturated hydrocarbon groups and the polydimethylsiloxane backbone containing hydrogen groups can each be either linear or branched.

[0534] Regarding the ratio of polydimethylsiloxane containing unsaturated hydrocarbons to polydimethylsiloxane containing hydrogen groups, the preferred molar ratio of all Si-H groups to all alkenes (Si-H group amount / alkene group amount) is 1.0 to 5.0.

[0535] If the molar ratio is 1.0 or higher, curability can be maintained; if it is 5.0 or lower, the amount of residual Si-H groups will not be excessive, and the peel force on the adhesive will not become too heavy, so it is preferred.

[0536] From this perspective, a value of 1.0 to 5.0 is preferred, with a value of 1.6 or higher or 4.8 or lower being particularly preferred, and a value of 2.0 or higher or 4.6 or lower being particularly preferred.

[0537] The silicone compound used in the mold release agent composition can be a solvent-curing silicone or a solvent-free curing silicone. Solvent-curing silicones and solvent-free curing silicones can also be used in combination.

[0538] Furthermore, both solvent-cured and solvent-free cured silicones are cured silicones with release properties, and are preferably silicones that involve an addition reaction between vinyl groups and groups having silicon-hydrogen bonds during the curing process (so-called addition-type silicones).

[0539] From the perspective of safety, such as the working environment and the risk of organic solvent explosions and fires, the aforementioned organosilicon compounds are preferably used in the form of organosilicon emulsions.

[0540] When emulsifying organosilicon compounds, surfactant components can be used as emulsion stabilizers.

[0541] As surfactants, nonionic surfactants and anionic surfactants can be listed.

[0542] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene phenyl ethers, glycerol alkyl ethers, glycerol fatty acid esters and their alkylene glycol adducts, polyglycerol fatty acid esters and their alkylene glycol adducts, propylene glycol fatty acid esters and their alkylene glycol adducts, and polyalkylene glycol fatty acid esters.

[0543] Examples of anionic surfactants include fatty acid soaps such as sodium stearate and triethanolamine palmitate, alkyl ether carboxylic acids and their salts, alkyl sulfonic acids, alkenyl sulfonates, sulfonates of fatty acid esters, alkyl sulfate salts, secondary higher alcohol sulfate salts, alkyl and allyl ether sulfate salts, fatty acid ester sulfate salts, polyoxyethylene alkyl sulfate salts, sulfate salts such as turmeric oil, alkyl phosphates, ether phosphates, alkyl allyl ether phosphates, and amide phosphates. Among these, nonionic surfactants are preferred, and from the viewpoint of the stability of silicone emulsions, polyoxyethylene alkyl ethers and polyoxyethylene phenyl ethers are more preferred.

[0544] Examples of polyoxyethylene alkyl ethers include polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, and polyoxybutylene alkyl ethers. Among these, polyoxyethylene alkyl ethers are preferred. Furthermore, the alkyl group is preferably a straight-chain or branched alkyl group with 8 to 30 carbon atoms, and more preferably a straight-chain or branched alkyl group with 8 to 16 carbon atoms.

[0545] Examples of polyoxyethylene phenyl ethers include polyoxyethylene phenyl ether, polyoxypropylene phenyl ether, and polyoxybutylene phenyl ether. Among these, polyoxyethylene phenyl ether is preferred. Furthermore, the phenyl group is preferably an unsubstituted or substituted phenyl group, and more preferably a styrene-substituted phenyl group obtained by substituting the hydrogen atom of the phenyl group with a styrene group.

[0546] (Compounds containing long-chain alkyl groups)

[0547] Compounds containing long-chain alkyl groups refer to compounds having straight-chain or branched alkyl groups with 6 or more carbon atoms, preferably 8 or more, and more preferably 12 or more carbon atoms.

[0548] Examples of alkyl groups include hexyl, octyl, decyl, lauryl, octadecyl, and behenyl, which have approximately 6 to 30 carbon atoms. Compounds containing alkyl groups include various polymers containing long-chain alkyl groups, amines containing long-chain alkyl groups, ethers containing long-chain alkyl groups, and quaternary ammonium salts containing long-chain alkyl groups. Considering heat resistance and staining properties, polymers are preferred. Furthermore, from the viewpoint of effectively obtaining mold release properties, polymers having long-chain alkyl groups in their side chains are more preferred.

[0549] Polymer compounds with long-chain alkyl groups on their side chains can be obtained by reacting a polymer with a reactive group with a compound containing an alkyl group that can react with that reactive group. Examples of such reactive groups include hydroxyl, amino, carboxyl, and acid anhydride groups. Examples of compounds containing these reactive groups include polyvinyl alcohol, polyethyleneimine, polyethyleneamine, polyester resins containing reactive groups, and poly(meth)acrylic resins containing reactive groups. Among these, polyvinyl alcohol is preferred considering demolding properties and ease of processing. The degree of polymerization of the polyvinyl alcohol used is not particularly limited, but is generally 100 or more, preferably in the range of 300 to 40,000. In addition, the degree of saponification of polyvinyl alcohol is not particularly limited, but is generally 70 mol% or more, preferably in the range of 70 to 99.9 mol%, more preferably 80 to 97 mol%, and particularly preferably 86 to 95 mol%.

[0550] Examples of alkyl-containing compounds that can react with reactive groups include: hexyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate, behenyl isocyanate, and other isocyanates containing long-chain alkyl groups; hexanoyl chloride, octanoyl chloride, decanoyl chloride, lauroyl chloride, octadecyl acyl chloride, behenyl chloride, and other acyl chlorides containing long-chain alkyl groups; amines containing long-chain alkyl groups; and alcohols containing long-chain alkyl groups. Among these, isocyanates containing long-chain alkyl groups are preferred for ease of processing, and octadecyl isocyanate is particularly preferred.

[0551] In addition, polymers with long-chain alkyl groups in their side chains can also be obtained by polymerizing long-chain alkyl methacrylates or by copolymerizing long-chain alkyl methacrylates with other vinyl-containing monomers. Examples of long-chain alkyl methacrylates include hexyl methacrylate, octyl methacrylate, decyl methacrylate, lauryl methacrylate, octadecyl methacrylate, and behenyl methacrylate.

[0552] When using an organosilicon compound as the aforementioned release agent, the content of the organosilicon compound in the release agent composition, based on its proportion to all non-volatile components in the release agent composition, is preferably in the range of 50-100% by mass, more preferably 70-100% by mass, further preferably 90-99% by mass, and particularly preferably 95-99% by mass. If the release layer contains 50% or more of the organosilicon compound, sufficient release properties can be obtained, which is therefore preferred. It should be noted that by setting this content to 99% or less, compounds containing (meth)acryloyl groups, as described later, can be included, thus further improving the adhesion to the polyester film.

[0553] When using a release agent other than organosilicon compounds (e.g., compounds containing long-chain alkyl groups, waxes, fluorinated compounds, etc.) as the aforementioned release agent, the content of the release agent other than organosilicon compounds in the release agent composition, based on its proportion to all non-volatile components in the release agent composition, is preferably in the range of 10 to 90% by mass, more preferably 20 to 80% by mass, further preferably 30 to 70% by mass, and particularly preferably 50 to 70% by mass. By setting this content to 10% by mass or more, good mold release properties are achieved. Furthermore, by setting this content to 90% by mass or less, sufficient solvent resistance can be obtained.

[0554] ((crosslinking agent))

[0555] When using a release agent other than an organosilicon compound, the release agent composition preferably contains a crosslinking agent. There are no particular limitations on the crosslinking agent used; conventionally known crosslinking agents can be used. By using a crosslinking agent, the strength of the release layer can be improved, and a layer in which the release components are less prone to extended adhesion can be formed.

[0556] Examples of crosslinking agents include melamine compounds, oxazoline compounds, epoxy compounds, carbodiimide compounds, isocyanate compounds, and silane coupling compounds. From the viewpoint of enhancing the strength of the release layer and improving adhesion to the polyester film, melamine compounds are preferred as crosslinking agents. In the release agent composition, one type of crosslinking agent may be used alone, or two or more may be used in combination.

[0557] It should be noted that the specific manner and preferred manner in which the crosslinking agent may be contained in the release agent composition are the same as those in the aforementioned resin composition, and all of them can be cited. That is, the substances exemplified as crosslinking agents in the release agent composition are the same as those exemplified as crosslinking agents in the aforementioned resin composition.

[0558] When the release agent composition contains a crosslinking agent, the content of the crosslinking agent in the release agent composition, based on its proportion to all non-volatile components in the release agent composition, is preferably in the range of 10 to 90% by mass, more preferably 20 to 80% by mass, further preferably 30 to 70% by mass, and particularly preferably 30 to 50% by mass. By setting this content to 10% by mass or more, the strength of the release layer can be improved. Furthermore, by setting this content to 90% by mass or less, sufficient release properties can be ensured.

[0559] (((Compounds containing (meth)acryloyl)))

[0560] When using a silicone compound as a release agent, the release agent composition may further contain a compound containing a (meth)acryloyl group. By containing a compound containing a (meth)acryloyl group, the adhesion to the polyester film can be further improved.

[0561] The aforementioned compounds containing a (meth)acryloyl group include polymeric (meth)acrylate compounds and monomeric (meth)acrylate compounds, either one of which can be used. Alternatively, they can be used in combination. Here, polymeric (meth)acrylate compounds refer to macromolecular monomers.

[0562] Examples of (meth)acrylate compounds include, for example, urethane (meth)acrylate compounds, epoxy (meth)acrylate compounds, polyester (meth)acrylate compounds, polyalkylene (meth)acrylate compounds, and other (meth)acrylate compounds. Among these, urethane (meth)acrylates, or mixtures comprising urethane (meth)acrylates and (meth)acrylate compounds other than urethane (meth)acrylates, are preferred as compounds containing (meth)acrylate groups.

[0563] As the urethane (meth)acrylate compound, conventionally known substances can be used without particular limitation. Examples include compounds obtained by reacting a hydroxyl-containing (meth)acrylate compound with an isocyanate compound, and compounds obtained by reacting a hydroxyl-containing (meth)acrylate compound with a polyol and an isocyanate compound. The urethane (meth)acrylate compound can be a polymer or a monomer, but from the viewpoint of adhesion to polyester films, a polymer is preferred.

[0564] Examples of (meth)acrylate compounds containing hydroxyl groups include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glyceryl mono(meth)acrylate, glyceryl di(meth)acrylate, diglyceryl mono(meth)acrylate, diglyceryl tri(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol mono(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, sorbitol di(meth)acrylate, sorbitol tri(meth)acrylate, sorbitol tetra(meth)acrylate, sorbitol penta(meth)acrylate, and sorbitol mono(meth)acrylate. These products include di(meth)acrylates, di(meth)acrylates, adducts of glycidyl acrylate and (meth)acrylate, reaction products of 2 molecules of (meth)acrylate and 1 molecule of 1,6-hexanediol diglycidyl ether, reaction products of 2 molecules of epoxy (meth)acrylate and 1 molecule of neopentyl glycol diglycidyl ether, reaction products of 2 molecules of (meth)acrylate and 1 molecule of bisphenol A diglycidyl ether, reaction products of 2 molecules of (meth)acrylate and the diglycidyl ether form of the propylene oxide adduct of bisphenol A, reaction products of 2 molecules of (meth)acrylate and 1 molecule of phthalic acid diglycidyl ether, reaction products of 2 molecules of (meth)acrylate and 1 molecule of polyethylene glycol diglycidyl ether, reaction products of 2 molecules of (meth)acrylate and 1 molecule of polypropylene glycol diglycidyl ether, and reaction products of (meth)acrylate and polyol diglycidyl ether. These products can be used alone or in combination.

[0565] Among these, from the viewpoint of more effectively improving the adhesion between organosilicon compounds and polyester films, substances containing three or more (meth)acryloyl groups per molecule, such as diglycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, sorbitol tri(meth)acrylate, sorbitol tetra(meth)acrylate, and sorbitol penta(meth)acrylate, are preferred. More preferably, substances containing five or more (meth)acryloyl groups per molecule, such as dipentaerythritol penta(meth)acrylate and sorbitol penta(meth)acrylate, are preferred.

[0566] Isocyanate compounds refer to isocyanates, or compounds with isocyanate derivative structures represented by isocyanates or terminally capped isocyanates. Examples of isocyanates include aromatic isocyanates such as toluene diisocyanate, phenylene diisocyanate, methylene diphenyl diisocyanate, phenyl diisocyanate, and naphthalene diisocyanate; aliphatic isocyanates with aromatic rings such as α,α,α',α'-tetramethylphenylene diisocyanate; aliphatic isocyanates such as methylene diisocyanate, ethylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, and hexamethylene diisocyanate; cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, hydrogenated phenylene diisocyanate, methylene bis(4-cyclohexyl) isocyanate, and isopropylidene dicyclohexyl diisocyanate. These isocyanates can also be reactants of various polymers and compounds. Additionally, examples include biuret compounds, isocyanurate compounds, urea diketides, carbodiimide modifiers, and other polymers and derivatives of these isocyanates. They can be used alone or in combination. From the viewpoint of improving the adhesion of the release layer to the polyester film, aliphatic isocyanates or alicyclic isocyanates are preferred, with alicyclic isocyanates being more preferred.

[0567] Examples of polyols include polycarbonate polyols, polyester polyols, and polyether polyols. High molecular weight polyols and low molecular weight polyols can be used.

[0568] There are no particular limitations on the high molecular weight polyols, but a number average molecular weight of 400 to 8000 is preferred, and 400 to 4000 is more preferred. When the number average molecular weight is in this range, it provides a suitable viscosity and can result in a good appearance of the release layer.

[0569] Examples of high molecular weight polyols include polycarbonate polyols, polyester polyols, and polyether polyols. Polycarbonate polyols are preferred for improving adhesion to polyester films.

[0570] Polycarbonate polyols are obtained by a dealcoholization reaction between polyols and carbonate compounds. Examples of polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, neopentanediol, 3-methyl-1,5-pentanediol, 3,3-dihydroxymethylheptane, 1,4-benzenedimethanol, 1,3-benzenedimethanol, 4,4'-naphthalenedimethanol, and 3,4'-naphthalenedimethanol. Examples of carbonate compounds include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and ethylene carbonate. Examples of polycarbonate polyols obtained from their reactions include polyhexamethylene carbonate diol and polycyclohexane carbonate diol. Among these, polyhexamethylene carbonate diol is preferred from the viewpoint of the adhesion of the release layer to the polyester film.

[0571] Examples of polyester polyols include: polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their anhydrides and polyols (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-methyl-2- Polyester polyols and polyester polyols containing lactone compound derivative units, such as poly(propyl-1,3-propanediol), 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexanediol, dihydroxymethylcyclohexane, dimethylbenzene, dihydroxyethoxybenzene, alkyldialkylolamine, lactone diol, etc., are obtained by reacting these compounds.

[0572] Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polyethylidene propylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol.

[0573] As low molecular weight polyols, there are no particular limitations; for example, polyols with a number average molecular weight of 60 or higher but lower than 400 can be listed. Examples include: ethylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, and other aliphatic diols with 2 to 9 carbon atoms; 1,4... Diols with an alicyclic structure having 6 to 12 carbon atoms, such as cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-bis(hydroxyethyl)cyclohexane, 2,7-norbornanediol, tetrahydrofurandiol, and 2,5-bis(hydroxymethyl)-1,4-dioxane; dihydroxymethylalkanoic acids such as 2,2-dimethylolpropionic acid and 2,2-dimethylolbutyric acid; and low molecular weight polyols such as trimethylolpropane, pentaerythritol, and sorbitol. Among these, dihydroxymethylalkanoic acids are preferred from the viewpoint of improving the stability of aqueous dispersions of urethane (meth)acrylate compounds.

[0574] Examples of (meth)acrylate compounds include monofunctional (meth)acrylates, difunctional (meth)acrylates, and polyfunctional (meth)acrylates. Here, polyfunctional (meth)acrylates refer to compounds having three or more (meth)acrylate groups in one molecule.

[0575] (Meth)acrylate compounds can be either polymers or monomers. From the viewpoint of reactivity with organosilicon compounds, monomers are preferred.

[0576] As a monofunctional (meth)acrylate, there is no particular limitation. Examples include methyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, alkyl methacrylates, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, methoxypropyl methacrylate, and ethyl methacrylate. Oxypropyl esters and other alkoxyalkyl esters of (meth)acrylate, benzyl ester of (meth)acrylate, phenoxyethyl ester of (meth)acrylate and other aromatic (meth)acrylates, diaminoethyl ester of (meth)acrylate, diethylaminoethyl ester of (meth)acrylate and other amino-containing (meth)acrylates, methoxyethylene glycol (meth)acrylate, phenoxy polyethylene glycol (meth)acrylate, ethylene oxide modified (meth)acrylates of phenylphenol and other ethylene oxide modified (meth)acrylates, glycidyl ester of (meth)acrylate, tetrahydrofurfuryl ester of (meth)acrylate, (meth)acrylic acid, etc.

[0577] As a difunctional (meth)acrylate, there is no particular limitation. Examples include 1,4-butanediol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, tricyclodecane dimethylol dimethacrylate, bisphenol A ethylene oxide modified dimethacrylate, bisphenol F ethylene oxide modified dimethacrylate, glycerol dimethacrylate, trimethylolpropane dimethacrylate, pentaerythritol dimethacrylate, dipentaerythritol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, urethane dimethacrylate, and epoxy dimethacrylate.

[0578] As a multifunctional (meth)acrylate, there are no particular limitations. Examples include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, ethylene oxide-modified isocyanurate tri(meth)acrylate, and ε-caprolactone-modified tri(acryloyloxyethyl)isocyanurate, etc. Acrylic esters, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, di(trimethylolpropane) tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, tetramethylolmethane ethylene oxide modified tetra(meth)acrylate, ethylene oxide modified pentaerythritol tetra(meth)acrylate, etc., ethylene oxide modified pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc.

[0579] Among these, from the viewpoint of forming crosslinks more efficiently, difunctional (meth)acrylates or polyfunctional (meth)acrylates are preferred, and polyfunctional (meth)acrylates are more preferred. Specifically, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, di(trimethylolpropane)tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate are preferred, and trimethylolpropane tri(meth)acrylate and dipentaerythritol hexa(meth)acrylate are more preferred.

[0580] When the release agent composition contains a compound containing a (meth)acrylyl group, the content of the (meth)acrylyl-containing compound in the release agent composition, based on its proportion to all non-volatile components in the release agent composition, is preferably 1 to 50% by mass, more preferably 1 to 40% by mass, further preferably 2 to 30% by mass, and particularly preferably in the range of 2 to 10% by mass. By setting this content to 1% by mass or more, the adhesion to the polyester film can be improved. Furthermore, by setting this content to 50% by mass or less, sufficient release properties can be ensured.

[0581] (((Specially Preferred Method)))

[0582] From the viewpoint of obtaining excellent release properties, the release layer preferably contains an organosilicon compound as the aforementioned release agent.

[0583] Furthermore, from the viewpoint of obtaining excellent adhesion to the polyester film, when the release layer contains an organosilicon compound as the aforementioned release agent, it is preferable that the release agent composition further contains a compound containing (meth)acryloyl groups, or when it contains long-chain alkyl groups as the aforementioned release agent, it is preferable that the release agent composition further contains a crosslinking agent.

[0584] Furthermore, from the viewpoint of further reducing the aforementioned air leakage index and further improving the operability of the release film, the release layer preferably contains a compound containing long-chain alkyl groups as the aforementioned release agent.

[0585] Thus, based on the priority characteristics, the aforementioned preferred method can be selected appropriately.

[0586] (((Other ingredients)))

[0587] In addition, without prejudice to the spirit of the present invention, besides the above-mentioned components, adhesive resins, particles, defoamers, coatability modifiers, surfactants, thickeners, organic lubricants, ultraviolet absorbers, antioxidants, foaming agents, dyes, pigments, and other additives may be further appropriately blended. The specific manner in which the adhesive resins may be contained in the release agent composition is the same as that in the aforementioned resin compositions, and all of them may be cited.

[0588] In addition, when using organosilicon compounds as release agents, appropriate amounts of platinum group metal catalysts and reactive re-exfoliation modifiers can be added.

[0589] (((solvent)))

[0590] The release agent composition can be diluted with a solvent to prepare a coating liquid. That is, the release agent composition can be applied to the polyester film in the form of a liquid coating liquid, and dried and cured as needed to form a release layer.

[0591] It should be noted that the components constituting the mold release agent composition (mold release agent, any added crosslinking agent and compounds containing (meth)acryloyl groups, other components, etc.) can be dissolved in a solvent or dispersed in a solvent.

[0592] When preparing a coating liquid, the concentration of all non-volatile components of the release agent composition in the coating liquid is preferably 0.1 to 50% by mass. If it is 0.1% by mass or more, a release layer of the desired thickness can be formed efficiently. On the other hand, if it is 50% by mass or less, the appearance of the release layer can be improved by suppressing the viscosity during coating, and the stability in the coating liquid can also be improved.

[0593] The specific and preferred methods of using solvents for dilutable release agent compositions are the same as those for dilutable solvents in the aforementioned resin compositions, and all of them can be cited.

[0594] It can be inferred that the release layer contains unreacted, reacted compounds, or mixtures thereof of the components constituting the release agent composition (release agent, arbitrarily added crosslinking agent and compounds containing (meth)acryloyl groups, other components, etc.).

[0595] It should be noted that the analysis of each component in the release layer can be performed, for example, by TOF-SIMS, ESCA, or fluorescence X-ray.

[0596] <Method for forming the release layer>

[0597] Next, the method for forming the release layer constituting the release film will be described. The specific method and preferred method for forming the release layer are the same as those for forming the resin layer, and all of them can be cited.

[0598] That is, the release layer is preferably formed by online coating during the film-making process of polyester film, which involves treating the surface of the film.

[0599] In addition, not limited to the following, for example, in sequential biaxial stretching, especially after coating a uniaxially stretched film stretched along the length direction (longitudinal direction), the method of stretching in the transverse direction is excellent.

[0600] The preferred coating amount of the non-volatile components in the release layer is 0.001–1.0 g / m². 2 More preferably, it is 0.005–0.5 g / m 2 Further preferably, it is 0.01–0.2 g / m 2 If the coating amount is 0.001 g / m 2 The above ensures sufficient mold release properties. Additionally, if the coating amount is 1.0 g / m²... 2 The following measures can suppress the deterioration of the coating appearance and the occurrence of insufficient curing of the coating.

[0601] It should be noted that the coating amount can be calculated based on the concentration of non-volatile components in the coating liquid, the coating amount before drying derived from the consumption of the coating liquid, the transverse stretch ratio, etc.

[0602] In addition, the amount of non-volatile components coated is the amount coated in the release film, for example, the amount coated after drying and stretching in the case of drying and stretching.

[0603] <<<Physical Properties of Release Films>>>

[0604] The bearing length ratio (Rmr(80)) of the roughness curve at a cut level of 80% of the resin layer surface of the release film is less than 94%.

[0605] The support length ratio (Rmr(c)) is one of the line roughness parameters (JIS B 0601), which represents the ratio of the support length ML(c) of the profile curve element cut at the horizontal level c (height % or μm) to the evaluation length Ln, and is calculated by the following equation (3-1-1).

[0606]

[0607] Here, the inventors believe that the support length ratio (Rmr(80)) is effective as an indicator of the concave-convex distribution of the concave-convex structure. For example, the value of the support length ratio (Rmr(80)) decreases when the concave distribution is large, and the value of the support length ratio (Rmr(80)) increases when the convex distribution is large. The smaller the support length ratio (Rmr(80)), the larger the gap formed between the films when the film is wound into a roll, the easier it is to expel air, and the better the winding performance.

[0608] The bearing length ratio (Rmr(80)) of the roughness curve at 80% of the cutting level is, as described above, 94% or less, preferably 90% or less, more preferably 76% or less, even more preferably 70% or less, particularly preferably 65% ​​or less, and especially preferably 58% or less. The lower limit is not particularly limited, but is approximately 1%, preferably 4%, and more preferably 6%.

[0609] The aforementioned support length ratio (Rmr(80)) can be adjusted by the composition and content of the aforementioned resin composition.

[0610] Furthermore, the bearing length ratio (Rmr(50)) of the roughness curve at a cut level of 50% of the resin layer surface is 60% or less, more preferably 40% or less, and even more preferably 20% or less. The lower limit is not particularly limited, but is approximately 1%, preferably 3%, and more preferably 5%.

[0611] Here, the inventors believe that it is effective to consider the support length ratio (Rmr(80)) as an indicator of the unevenness distribution of the uneven structure, in addition to considering the support length ratio (Rmr(80)). For example, even with the same support length ratio (Rmr(80)), it can be said that when the support length ratio (Rmr(50)) is small, the convex shape is thinner, and when the support length ratio (Rmr(50)) is large, the convex shape is coarser. Therefore, the smaller the support length ratio (Rmr(50)), the finer the unevenness, the larger the gap formed between the films when the film is wound into a roll, the easier it is to expel air, and the better the winding performance.

[0612] The aforementioned support length ratio (Rmr(50)) can also be adjusted by the composition and content of the aforementioned resin composition.

[0613] Furthermore, the arithmetic mean roughness (Ra) of the resin layer surface is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 20 nm or more, particularly preferably 30 nm or more, and especially preferably 35 nm or more. There is no particular upper limit, but 600 nm is preferred, more preferably 400 nm, and even more preferably 200 nm. If the arithmetic mean roughness (Ra) is 5 nm or more, the resin layer can be said to have a fine uneven structure, resulting in good processability of the release film. Conversely, if the arithmetic mean roughness (Ra) is 600 nm or less, the uneven structure of the resin layer can be considered to be a sufficiently fine shape.

[0614] Arithmetic mean roughness (Ra) is one of the line roughness parameters (JIS B 0601), representing the average value of the average height difference from the mean surface.

[0615] That is, extract a portion of the reference length L, set the average line of the extracted portion as the x-axis, set the direction of the vertical magnification as the y-axis, and use y=Z(x) to represent the roughness curve, which is then calculated according to the following formula (3-1-2).

[0616]

[0617] Furthermore, the ten-point average roughness (Rzjis) of the resin layer surface is preferably 28 nm or more, more preferably 70 nm or more, even more preferably 90 nm or more, and particularly preferably 120 nm or more. There is no particular upper limit, but 800 nm is preferred, more preferably 600 nm, and even more preferably 500 nm. If the ten-point average roughness (Rzjis) is 28 nm or more, the resin layer can be said to have a sufficiently uneven structure. Conversely, if the ten-point average roughness (Rzjis) is 800 nm or less, the uneven structure of the resin layer can be considered to be a sufficiently fine shape.

[0618] The ten-point average roughness (Rzjis) is one of the line roughness parameters (JIS B 0601). It represents the sum of the average of the fifth peak height (Zp) and the fifth valley depth (Zv) along the reference length L, and is calculated according to the following formula (3-1-3).

[0619]

[0620] The arithmetic mean roughness (Ra) and ten-point mean roughness (Rzjis) mentioned above can be adjusted by the composition and content of the aforementioned resin composition.

[0621] It should be noted that the bearing length ratio (Rmr(80)), bearing length ratio (Rmr(50)), arithmetic mean roughness (Ra), and ten-point mean roughness (Rzjis) of the resin layer surface were measured using an atomic force microscope (scanning probe microscope) according to the method described in the examples. Measurements based on an atomic force microscope (scanning probe microscope) can capture finer surface structures, resulting in values ​​that strongly reflect the effects of the resin layer.

[0622] The peel strength of the adhesive tape in the release film is preferably 500 mN / cm or less, more preferably 400 mN / cm or less, even more preferably 300 mN / cm or less, and particularly preferably 200 mN / cm or less. If the peel strength of the adhesive tape is 500 mN / cm or less, the release film can be said to have sufficient release properties. There is no particular limitation on the lower limit value, which is approximately 0.1 mN / cm.

[0623] It should be noted that the peel force of the release layer tape described above can be measured using the method described in the examples.

[0624] The static friction coefficient between the resin layer surface and the release layer surface of the release film is preferably 1.0 or less, more preferably 0.8 or less, even more preferably 0.6 or less, and particularly preferably 0.4 or less.

[0625] When the release film is rolled into a roll, the coefficient of friction between the resin layer surface and the release layer surface is important because the resin layer surface is in contact with the release layer surface.

[0626] Therefore, if the static friction coefficient is within the specified range, the sliding properties become good due to the uneven structure of the resin layer, thus optimizing the operability of the release film.

[0627] It should be noted that the above-mentioned static friction coefficient can be measured using the method described in the examples.

[0628] The air leakage index can be used as an indicator to evaluate the operability of release films, such as their rollability. A low air leakage index allows air trapped during roll-up to escape easily, preventing defects in the roll appearance such as wrinkles and uneven end faces. Conversely, a high air leakage index means that trapped air is expelled after sufficient time, especially during transport, sometimes causing the film to shift in the core direction or develop scratches due to this shift, which becomes a problem. Release films do not exhibit these defects.

[0629] An air leakage index of, for example, below 150,000 seconds is acceptable. More preferably, it is below 100,000 seconds; even more preferably, below 70,000 seconds; and particularly preferably, below 30,000 seconds. If it is below 150,000 seconds, it can be said to be quite feasible.

[0630] The air leakage index can be improved not only by the uneven structure of the resin layer, but also by the roughness of the smooth surface of the polyester film. Specifically, it is preferable that the arithmetic mean roughness (Sa) of the polyester film surface on the side opposite to the surface where the resin layer is formed (i.e., the smooth surface) is 15 nm or less, and the maximum peak height (Sp) is 800 nm or less, or both. Here, the opposite surface can be the film surface used for processing in various applications such as release films for forming green sheets of multilayer ceramic capacitors, release films for interlayer insulating resins, and release films for dry film resists, etc., and can be coated or laminated with various materials as described later.

[0631] Furthermore, in cases requiring more precise processing, it is preferable that the arithmetic mean roughness (Sa) of the polyester film surface on the opposite side (i.e., the smooth surface of the film used for processing) is 9 nm or less, and the maximum peak height (Sp) is 500 nm or less, or both. In this way, with an extremely high smoothness of the film surface, more precise processing can be achieved by utilizing the film's smoothness, and the air leakage index is improved to the aforementioned range through the uneven structure of the resin layer, resulting in good rollability and optimized operability of the release film.

[0632] Thus, the air leakage index depends on the smoothness of the polyester film surface on the side opposite to where the resin layer is formed. When smoothness is required for the polyester film, the improved operability resulting from the uneven structure of the resin layer can also be obtained.

[0633] It should be noted that the air leakage index described above can be measured using the method described in the examples.

[0634] <<<Applications of Release Film>>>

[0635] The resin layer is characterized by being composed of a resin composition containing specific compounds and having a specific roughness structure, thereby enabling even thin films to form a phase-separated structure and exhibit a fine uneven structure. In addition, it is characterized by focusing on the bearing length ratio (Rmr(80)) as an indicator of the roughness structure, which represents the uneven distribution of the uneven structure.

[0636] Based on this design concept, it is possible to achieve precise control of fine, uneven structures that are difficult to achieve in conventional particle-mixing film manufacturing methods. Furthermore, by employing a specific roughness structure, even thin films can have improved air expulsion ease, resulting in release films with excellent handling characteristics.

[0637] Release films can be used for a variety of purposes to improve operability, and there are no particular limitations on their use.

[0638] As described above, due to its fine, uneven structure, it exhibits excellent rollability when used for sheet forming, particularly when winding highly smooth films into rolls, and is less prone to wrinkling. Therefore, it is suitable as a release film for sheet forming. Examples of release films for sheet forming include various applications such as green sheet forming for multi-layer ceramic capacitors (MLCCs), interlayer insulating resin, dry film resist (DFR), and multilayer circuit boards. In these applications, the release film can be used as a support. Specifically, in the manufacturing process of multi-layer ceramic capacitors, especially automotive multi-layer ceramic capacitors, the release film can be suitable as a support for ceramic green sheets.

[0639] The release film for sheet forming can be used in processes where various materials are coated or laminated on at least one side of the film to form various sheets, such as green sheets. It is preferable that the various materials are coated or laminated on the release film side.

[0640] <<<Polyester Film>>

[0641] As described above, the laminated polyester film of the present invention can form a fine uneven structure even in thin films, and is a laminated polyester film with excellent processability, such as when the film is rolled into a roll.

[0642] As a specific example, the following components may be appropriately listed.

[0643] Preferably, it is a polyester film roll, which is formed by winding up a laminated polyester film having a polyester film and a resin layer as a curable resin layer on one side of the aforementioned polyester film.

[0644] The aforementioned laminated polyester film satisfies all of the following conditions (1) to (4).

[0645] (1) The aforementioned resin layer has an uneven structure.

[0646] (2) The aforementioned resin layer is a cured product of a cured resin composition containing (A) a release agent, (B) a crosslinking agent and (D) microparticles.

[0647] (3) The average surface roughness (Sa) of the aforementioned resin layer is 1 to 9 nm.

[0648] (4) The root mean square slope (Sdq) of the aforementioned resin layer surface is 0.40 to 0.80.

[0649] Here, (1) and (2) have been explained in the same way as described above.

[0650] Regarding condition (3), the average surface roughness (Sa) in this polyester film roll is preferably 1 to 9 nm. The definition of average surface roughness (Sa) has been explained as described above.

[0651] For laminated polyester films, if the average surface roughness (Sa) of the resin layer is below 9 nm, the smoothness of the resin layer surface will not be lost, and defects such as pinholes caused by the fine unevenness of the laminated polyester film surface are less likely to occur. In addition, if the average surface roughness (Sa) is above 1 nm, the disadvantage of the film surface being too flat and easily damaged is less likely to occur.

[0652] From the perspective of thinning ceramic green sheets and suppressing pinholes, the average surface roughness (Sa) of the resin layer surface of the laminated polyester film is more preferably 2 to 7 nm.

[0653] It should be noted that, in laminated polyester films, the surface on which the resin layer is disposed is typically, as described later, the side opposite to the surface on which various materials are coated or laminated (processed surface) during the manufacturing of ceramic layers, etc. However, even on the opposite surface, by reducing the average surface roughness (Sa) as described above, it is possible to prevent the unevenness of the opposite surface from being transferred to the processed surface, thereby preventing pinholes or inability to cope with thinning due to the transferred unevenness.

[0654] Regarding condition (4), the root mean square slope (Sdq) in the polyester film roll is preferably 0.40 to 0.80.

[0655] The inventors focused on the shape of the protrusions on the surface of the resin layer, especially the inclined structure, and found that by setting the root mean square slope (Sdq) to a certain value or above, good air leakage between the films can be exhibited when the film is wound into a roll, thereby improving the winding performance.

[0656] The root mean square slope (Sdq) is one of the surface roughness parameters determined by measurement according to ISO 25178, and is represented by the following formula (4-1-1).

[0657] The root mean square slope (Sdq) represents the average magnitude of the local slope of the unevenness of a surface; a larger value indicates a steeper surface.

[0658]

[0659] As described above, the root mean square slope (Sdq) of the resin layer surface is preferably 0.40 to 0.80. If the root mean square slope (Sdq) is below 0.80, defects such as pinholes are less likely to occur, damage prevention is maintained, and it is easier to handle the thin-film production of ceramic green sheets. If the root mean square slope (Sdq) is above 0.40, good air leakage between films can be exhibited, resulting in good winding properties. In addition, the film surface is not excessively flat, the film's slip properties are maintained, and it is less prone to damage, thus maintaining damage prevention. Furthermore, it is easier to handle the long strip production of polyester film rolls.

[0660] In addition, by satisfying the above range, even in long, rolled films, the protrusions on the surface of the resin layer are not easily deformed, resulting in a good roll appearance.

[0661] From the perspective of improving damage prevention and addressing the issues of longer polyester film rolls and thinner ceramic sheets, the root mean square slope (Sdq) is more preferably 0.40 to 0.60.

[0662] It should be noted that it is speculated that by containing microparticles in the resin layer, the inclination of the protrusion becomes steeper, and the root mean square slope (Sdq) easily falls within the range specified above, thus exhibiting good air leakage between the films.

[0663] From the viewpoint of suppressing pinholes, the maximum peak height (Sp) on the surface of the resin layer of the laminated polyester film is, for example, 150 nm or less, preferably 100 nm or less, and more preferably 80 nm or less. There is no particular limitation on the lower limit of the maximum peak height (Sp) on the surface of the resin layer, but from the viewpoint of film processability, it is preferably 10 nm or more, more preferably 15 nm or more, and even more preferably 20 nm or more.

[0664] It should be noted that the definition of maximum peak height (Sp) is as described above.

[0665] The height of the protruding peak (Spk) is one of the surface roughness parameters determined according to ISO 25178. The height of the protruding peak (Spk) on the surface of the resin layer is preferably 70 nm or more, more preferably 100 nm or more, even more preferably 150 nm or more, and particularly preferably 200 nm or more.

[0666] By satisfying the aforementioned range, good film processability can be ensured even if the maximum peak height (Sp) of the unevenness on the surface of the resin layer is small and the air leakage index is small due to the protrusions.

[0667] There is no particular limitation on the height of the prominent peak (Spk), for example, it can be below 500 nm.

[0668] The ratio (Sp / Sa) of the maximum peak height (Sp) to the average surface roughness (Sa) of the resin layer surface is preferably 30 or less, more preferably 25 or less. By keeping the ratio (Sp / Sa) at 30 or less, there are no large protrusions on the resin layer surface, the generation of pinholes and the like is suppressed, and it is also easier to handle thinning. The ratio (Sp / Sa) is not particularly limited, for example, it can be 1 or more, or it can be 3 or more.

[0669] <<<Explanation of the statement>>>

[0670] In this invention, the term "film" also includes the case of "sheet", and the term "sheet" also includes the case of "film".

[0671] In this invention, when the term is recorded as "X~Y" (where X and Y are arbitrary numbers), unless otherwise specified, it includes the meaning of "X or more and Y or less", and also includes the meaning of "preferably greater than X" or "preferably less than Y".

[0672] In addition, when it is recorded as "X or above" (where X is any number), unless otherwise specified, it includes the meaning of "preferably greater than X". When it is recorded as "Y or below" (where Y is any number), unless otherwise specified, it also includes the meaning of "preferably less than Y".

[0673] Example

[0674] The present invention will be described in more detail below through examples.

[0675] The present invention is not limited to the following embodiments as long as it does not depart from its spirit.

[0676] <Evaluation Methods>

[0677] (1-1) Intrinsic viscosity (IV) of polyester

[0678] 1g of polyester, from which incompatible components have been removed, was accurately weighed and dissolved in 100mL of a phenol / tetrachloroethane mixture of 50 / 50 (mass ratio). The viscosity was measured at 30°C using a "VMS-022UPC·F10" viscometer (manufactured by Lihe Co., Ltd.).

[0679] (1-2) Average particle size

[0680] To determine the average particle size, observe more than 10 particles using a scanning electron microscope (SEM) and measure their diameters. Calculate the average value as the average particle size (average first-order particle size). In the case of non-spherical particles, measure the average of the longest and shortest diameters as the diameter of each particle.

[0681] (1-3) The uneven structure of the resin layer

[0682] Measurements were performed using a scanning probe microscope (SPM-9700, manufactured by Shimadzu Corporation) under the following conditions.

[0683] Probe: Silicon cantilever

[0684] Scanning mode: Dynamic mode

[0685] Scan range: 25μm × 25μm

[0686] Scan speed: 0.8Hz

[0687] Number of pixels: 512×512 data points

[0688] Based on the obtained data, observe the cross-sectional shape with a width of 25μm. If there are multiple protrusions or concave parts with a height difference of more than 10nm at more than 80% of the positions, it is judged as "having" a concave-convex structure. If multiple protrusions or concave parts cannot be identified, it is judged as "not having" a concave-convex structure.

[0689] (1-4) Hansen solubility parameters (HSP) of each resin [δd, δp, δh]

[0690] Approximately 0.05 g of the solids of each resin were added to a 20 mL glass bottle. Solvent was then added to bring the solids ratio to 1% by mass. After stirring for 20 seconds, the mixture was allowed to stand at 23°C. The glass bottle was checked after 24 hours. Solvents that dissolved were considered good solvents, while those that did not dissolve or swell were considered poor solvents. The Hansen solubility parameters (HSP) [δd, δp, δh] were calculated using the commercially available Hansen solubility parameter calculation software HSP. A total of 21 solvents were evaluated according to Table 1 above.

[0691] (1-5) Hansen solubility parameter (HSP) distance

[0692] Using the HSP values ​​determined by the methods described in (1-4) above, the HSP distance between each compound (A) and compound (B) is calculated according to the following formula.

[0693] HSP distance = {4×(δd1-δd2)} 2 +(δp1-δp2) 2 +(δh1-δh2) 2} 0.5

[0694] In this context, δd1, δp1, and δh1 represent the δd, δp, and δh of compound (A) in the Hansen solubility parameters [δd, δp, δh], while δd2, δp2, and δh2 represent the δd, δp, and δh of compound (B).

[0695] It should be noted that δp1≤δp2.

[0696] (1-6) Arithmetic mean roughness (Ra) and ten-point mean roughness (Rzjis) of the resin layer surface

[0697] Based on the data obtained from the scanning probe microscope measured by the method described in (1-3) above, a 25 μm wide cross-sectional analysis was performed parallel to the stretching direction (i.e., transverse) of the tenter frame to determine the arithmetic mean roughness (Ra) and the ten-point mean roughness (Rzjis). Cross-sectional analysis data at 10 equal intervals along the film-forming direction (i.e., longitudinal) of the film were then averaged to obtain the final roughness.

[0698] (1-7) Support length ratio (Rmr(50)) and support length ratio (Rmr(80)) of the resin layer surface

[0699] Using the same method as described in (1-6) above, cross-sectional analysis was performed using a scanning probe microscope to determine the support length ratio at 50% of the cut horizontal (Rmr(50)) and the support length ratio at 80% of the cut horizontal (Rmr(80)). Cross-sectional analysis data were obtained at 10 equal intervals along the film-forming direction (i.e., longitudinal direction) of the film, and then averaged to obtain the final value.

[0700] (1-8) Arithmetic mean roughness (Sa) and maximum peak height (Sp) of the side surface opposite to the resin layer.

[0701] The VertScan (registered trademark) R550GML non-contact surface / layer cross-sectional shape measurement system manufactured by Ryukyu Systems Co., Ltd. was used to measure a 640μm × 480μm area on the thin film surface under the following conditions: CCD camera: SONY HR-50 1 / 3', objective lens: 20x, lens barrel: 1X Body, zoom lens: NoRelay, wavelength filter: 530 white, measurement mode: Wave. The arithmetic mean roughness (Sa) and maximum peak height (Sp) were calculated by averaging 10 points using the output based on fourth-order polynomial correction.

[0702] (1-9) Static friction coefficient

[0703] The static friction coefficient between the resin layer surface and the opposite side of the laminated polyester film is determined by the following method.

[0704] A film was adhered to a smooth glass plate 10 mm wide and 100 mm long, with the side opposite to the resin layer as the upper surface. A film cut to 18 mm wide and 120 mm long was placed on the plate with the resin layer side as the lower surface. An 8 mm diameter metal pin was then pressed onto the film, and the pin was slid along the length of the glass plate under a load of 30 g and a speed of 40 mm / min to measure the frictional force. The maximum value immediately after sliding was taken as the static friction coefficient. It should be noted that the measurement was conducted at room temperature (23 ± 1 °C) and humidity (50 ± 0.5 RH). The number of measurements (N) was set to 10, and the average value was used.

[0705] Static friction coefficient (μs) = Fs / weight load

[0706] (In the above formula, Fs is in grams (g), and the weight load is in grams (g).)

[0707] (1-10) Air Leakage Index

[0708] The test was conducted using a digital Buick smoothness testing machine (manufactured by Toyo Seiki Co., Ltd., "DB-2"), according to JIS P8119, under an atmosphere of 23°C and 50% RH. The pressure of the pressurization device was 100 kPa, and a 38 ml vacuum container was used. The time (in seconds) for 1 mL of air to flow, i.e., the time it takes for the pressure inside the container to change from 50.7 kPa to 48.0 kPa, was measured. Ten times the obtained number of seconds was taken as the air leakage index. The sample size of the test film was set to 70 mm square, and 20 sheets were stacked with the front and back sides overlapping to prepare the test laminated film.

[0709] A 5mm diameter hole was made in the center of the test laminated film, and the air leakage index was measured as described above. The higher the air leakage index value, the longer it takes for air to escape from the gaps between the films, thus indicating that the films are in closer contact with each other, and a greater risk of wrinkles when forming roll films.

[0710] <Materials Used>

[0711] The polyesters used in the examples and comparative examples are shown below.

[0712] [Polyester(A)]

[0713] 100 parts by mass of dimethyl terephthalate and 65 parts by mass of ethylene glycol are added to an ester exchange reaction tank equipped with a stirring device, a heating device and a distillate separation tower, and heated to 150°C to melt the dimethyl terephthalate.

[0714] Next, an ethylene glycol solution of magnesium acetate tetrahydrate was added, such that the amount of magnesium acetate added was 0.09% by mass relative to the resulting polyester.

[0715] Then, the temperature was raised to 225°C under normal pressure for 3 hours, and then stirred and maintained at 225°C for 1 hour and 15 minutes. The transesterification reaction was carried out while methanol was removed by distillation, and the transesterification reaction was essentially completed to obtain polyester oligomer.

[0716] Next, the aforementioned oligomers are transported to a polycondensation reaction tank equipped with a stirrer and a distillation pipe.

[0717] An ethylene glycol solution of magnesium acetate tetrahydrate was added to the delivered oligomer, such that the amount of magnesium acetate added was 0.09% by mass relative to the resulting polyester resin composition.

[0718] Then, an ethylene glycol solution of phosphoric acid was added as a heat stabilizer, such that the amount of phosphoric acid added was 0.017 by mass relative to the resulting polyester.

[0719] Next, a solution of tetrabutyl titanate as a polycondensation catalyst in ethylene glycol was added to the aforementioned oligomer at a mass concentration of 4.5 ppm (based on titanium atoms) relative to the obtained polyester.

[0720] Then, the pressure was reduced from 101.3 kPa to 0.4 kPa over 85 minutes, maintained at 0.4 kPa, and the temperature was increased from 225°C to 280°C over 2 hours. The temperature was then maintained at 280°C for 1.5 hours to carry out melt polycondensation reaction, resulting in polyester (A) with an intrinsic viscosity (IV) of 0.63 dL / g.

[0721] [Polyester(B)]

[0722] In the method for manufacturing polyester (A), 0.3% by mass of silica particles with an average particle size of 2 μm are added to polyester (A) before melt polymerization. Otherwise, polyester (B) with an intrinsic viscosity (IV) of 0.63 dL / g is obtained by using the same method as the method for manufacturing polyester (A).

[0723] [Polyester (C)]

[0724] 0.75% by mass of alumina particles with an average particle size of 0.05 μm were added to polyester (A) and the mixture was kneaded using a vented twin-shaft mixer to obtain polyester (C) with an intrinsic viscosity (IV) of 0.63 dL / g.

[0725] [Polyester(D)]

[0726] Instead of adding tetrabutyl titanate to polyester (A), antimony trioxide as a polycondensation catalyst was added at a mass ratio of 300 ppm based on antimony atoms relative to the composition of the obtained polyester resin. Otherwise, polyester (D) with an intrinsic viscosity (IV) of 0.63 dl / g was obtained in the same manner as polyester (A).

[0727] The resin composition obtained by stirring and mixing according to the compositions shown in Table 1-2 below was diluted with water to prepare coating solutions 1-1 to 1-23. The compounds used are shown below.

[0728] [Compound (A): Low polar compound (1-IA)]

[0729] Add 300g of oxidized polyethylene wax (melting point 105℃, acid value 16mgKOH / g, density 0.93g / mL, number average molecular weight 5000), 650g of deionized water, 50g of decaglycerol monooleate surfactant, and 10g of 48% potassium hydroxide aqueous solution to a 1.5L emulsification device equipped with a mixer, thermometer, and temperature controller. After purging with nitrogen, seal the device and stir at high speed at 150℃ for 1 hour. Then cool the mixture to 130℃ and pass it through a high-pressure homogenizer at 400 atmospheres. Cool the mixture to 40℃ to obtain a wax emulsion.

[0730] [Compound (A): Low polar compound (1-IB)]

[0731] In a four-necked flask, 200 parts by weight of xylene and 600 parts by weight of octadecyl isocyanate were added, and the mixture was heated with stirring. Starting from the moment the xylene began to reflux, 100 parts by weight of polyvinyl alcohol (with an average degree of polymerization of 500 and a degree of saponification of 88 mol%) were added in small amounts at 10-minute intervals over approximately 2 hours. After the addition of polyvinyl alcohol was completed, the mixture was refluxed for another 2 hours to bring the reaction to a complete stop. The reaction mixture was cooled to approximately 80°C and then added to methanol. The reaction product precipitated as a white precipitate. This precipitate was filtered, and 140 parts by weight of xylene was added. The mixture was heated until completely dissolved, and then methanol was added again to precipitate the product. This process was repeated several times. The precipitate was then washed with methanol, dried, and pulverized to obtain the final product.

[0732] [Compound (B): Adhesive Resin (1-IIA)]

[0733] An aqueous dispersion of an acrylic resin polymerized with the following composition

[0734] An emulsified polymer of ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-hydroxymethylacrylamide / acrylic acid = 65 / 21 / 10 / 2 / 2 (wt%) (emulsifier: anionic surfactant).

[0735] [Compound (B): Adhesive Resin (1-IIB)]

[0736] Polyvinyl alcohol with a saponification degree of 88 mol% and a polymerization degree of 500

[0737] [Compound (B): Adhesive Resin (1-IIC)]

[0738] An ammonium-containing polymer compound with a number average molecular weight of 30,000, synthesized from structural units of the following formula (5-1-1).

[0739]

[0740] [Compound (B): Adhesive Resin (1-IID)]

[0741] Aqueous dispersion of polyester resin copolymerized with the following composition

[0742] Monomer composition: (Acid component) Terephthalic acid / isophthalic acid / sodium isophthalic acid 5-sulfonate / / (Diol component) Ethylene glycol / 1,4-butanediol / diethylene glycol = 56 / 40 / 4 / / 70 / 20 / 10 (mol%)

[0743] [Compound (B): Crosslinking agent (1-IIIA)]

[0744] Melamine compound: Hexamethoxyhydroxymethylmelamine

[0745] [Compound (B): Crosslinking agent (1-IIIB)]

[0746] EPOCROS (manufactured by Nippon Shokubai Co., Ltd.), an oxazoline compound, has an oxazoline content of 7.7 mmol / g.

[0747] [Compound (C): Crosslinking catalyst (1-IV)]

[0748] 2-Amino-2-methylpropanol hydrochloride

[0749] [Compound (D): Particles (1-V)]

[0750] Silica particles with an average particle size of 0.005 μm

[0751] The HSP values ​​of each resin (1-IA) to (1-IIIB) determined by the methods described in (1-4) above are shown in Table 1-1.

[0752] [Table 2]

[0753] Table 1-1

[0754]

[0755] (Example 1-1)

[0756] A blend of polyester (A) and (B) in proportions of 94% and 6% by mass, respectively, was used as the outermost (surface) layer material, while polyester (A) was used solely as the intermediate layer material. The outermost and intermediate layer materials were fed to two separate extruders, melted at 285°C, and then co-extruded on cooling rollers set to 40°C with two different three-layer configurations (surface / intermediate / surface = 1 / 8 / 1 discharge ratio), allowing them to cool and solidify to obtain an unstretched sheet.

[0757] Next, the film is stretched 3.5 times its length while passing through a heated roller assembly at 85°C to produce a uniaxially stretched film. The coating weight (after drying and stretching) on ​​one side of this uniaxially stretched film is 0.10 g / m². 2 The coating solution 1-1, having the composition shown in Table 1-2 below, was applied. The film was then fed into a tenter frame and stretched 4.3 times its original length in the width direction at 100°C. Following heat treatment at 235°C, a 2% relaxation treatment in the width direction was performed to obtain a laminated polyester film with a thickness of 50 μm. The evaluation results are shown in Table 1-3.

[0758] (Examples 1-2 to 1-6)

[0759] In addition to using the coating liquids shown in Tables 1-2, laminated polyester films were obtained in the same manner as in Example 1-1. The evaluation results are shown in Tables 1-3.

[0760] (Examples 1-7)

[0761] A blend of polyester (A) and polyester (C) in proportions of 87% and 13% by mass, respectively, was used as the raw material for the outermost layer (layer A) on one side. Polyester (A) was used solely as the raw material for the intermediate layer (layer B), and polyester (A) was used solely as the raw material for the outermost layer (layer C) on one side. The raw materials for layers A, B, and C were fed to three extruders, melted at 280°C, and then co-extruded on cooling rollers set at 25°C with two different three-layer configurations (outer layer / intermediate layer / outer layer = 1.6 / 27.8 / 1.6 discharge rates). After cooling and solidification, unstretched sheets were obtained.

[0762] Next, the film is stretched 3.5 times its length while passing through a heated roller assembly at 86°C to produce a uniaxially stretched film. The coating weight (after drying and stretching) on ​​one side (the surface of layer C) of this uniaxially stretched film is 0.10 g / m². 2 The coating solution 1-1, having the composition shown in Table 1-2 below, was applied. The film was then fed into a tenter frame and stretched 4.5 times its original length in the width direction at 105°C. Following heat treatment at 230°C, a 2% relaxation treatment in the width direction was performed to obtain a laminated polyester film with a thickness of 31 μm. The evaluation results are shown in Table 1-3.

[0763] (Examples 1-8 to 1-25)

[0764] Using the coating solutions shown in Table 1-2, and changing the coating amount (after drying and stretching) to that shown in Table 1-3, laminated polyester films were obtained in the same manner as in Examples 1-7. The evaluation results are shown in Table 1-3.

[0765] (Examples 1-26)

[0766] Using only polyester (A) as the raw material for the outermost layer (layer A) on one side and only polyester (D) as the raw material for the intermediate layer, laminated polyester films were obtained in the same manner as in Examples 1-10. The evaluation results are shown in Tables 1-3.

[0767] (Examples 1-27 to 1-30)

[0768] Using the coating solutions shown in Table 1-2, and changing the coating amount (after drying and stretching) to that shown in Table 1-3, laminated polyester films were obtained in the same manner as in Examples 1-26. The evaluation results are shown in Table 1-3.

[0769] (Comparative Example 1-1)

[0770] Without a resin layer, a polyester film was obtained in the same manner as in Example 1-1. The evaluation results are shown in Tables 1-3.

[0771] (Comparative Examples 1-2)

[0772] Using the coating solutions shown in Table 1-2, except otherwise, laminated polyester films were obtained in the same manner as in Example 1-1. The evaluation results are shown in Table 1-3.

[0773] (Comparative Examples 1-3)

[0774] Without a resin layer, polyester films were obtained in the same manner as in Examples 1-7. The evaluation results are shown in Tables 1-3.

[0775] (Comparative Examples 1-4 to 1-5)

[0776] Using the coating solutions shown in Table 1-2, except otherwise, laminated polyester films were obtained in the same manner as in Examples 1-7. The evaluation results are shown in Table 1-3.

[0777] [Comparative Examples 1-6]

[0778] Without a resin layer, polyester films were obtained in the same manner as in Examples 1-26. The evaluation results are shown in Tables 1-3.

[0779] [Comparative Examples 1-7]

[0780] Using the coating solutions shown in Table 1-2, and changing the coating amount (after drying and stretching) to that shown in Table 1-3, laminated polyester films were obtained in the same manner as in Examples 1-26. The evaluation results are shown in Table 1-3.

[0781] [Table 3]

[0782] Table 1-2

[0783]

[0784] [Table 4]

[0785] Table 1-3

[0786]

[0787] It should be noted that in the HSP distances in Tables 1-3 above, for example, 1-I / 1-II represents the HSP distance between 1-I and 1-II. More specifically, 1-I / 1-II in Example 1-1 refers to the HSP distance between the low polarity compound (1-IA) and the binder resin (1-IIA).

[0788] In addition, polyester film A in Tables 1-3 above is the polyester film of Example 1-1, polyester film B is the polyester film of Example 1-7, and polyester film C is the polyester film of Example 1-26.

[0789] As shown in Tables 1-3, it can be seen that Examples 1-1 to 1-6, which are the laminated polyester films of the present invention, were formed by including compound (A) and compound (B). Figure 1 The uneven structure shown, and the support length ratio (Rmr(80)) at 80% of the cut level is less than 76%, thus becoming a suitable uneven shape, with a static friction coefficient as low as less than 1.0, good sliding properties, an air leakage index of less than 10000 seconds, and excellent exhaust properties, thus making it a film with excellent productivity such as winding properties.

[0790] On the other hand, Comparative Example 1-1 does not have a resin layer and therefore does not have an uneven structure. Furthermore, Comparative Example 1-2 does not contain compound (A) and therefore does not form an uneven structure. Therefore, these comparative examples have high coefficients of friction and air leakage indices, poor sliding and exhaust properties, and are films with poor operability.

[0791] Furthermore, Examples 1-7 to 1-30, due to their suitable uneven structure, exhibit low static friction coefficients and air leakage indices, as well as excellent sliding and winding properties, resulting in films with high productivity. In addition, the arithmetic mean roughness (Sa) and maximum peak height (Sp) of the opposite side of the resin layer are also low, making them excellent films suitable for precision processing.

[0792] On the other hand, Comparative Examples 1-3 to 1-4 and 1-6 to 1-7, like Comparative Examples 1-1 to 1-2, also lack a resin layer and compound (A), resulting in a very high air leakage index and a high static friction coefficient. Consequently, they exhibit low sliding and winding properties, making them films with poor productivity. Furthermore, although Comparative Example 1-5 has an uneven structure, its support length ratio (Rmr(80)) is high, thus lacking a suitable uneven structure. Therefore, while it has a low static friction coefficient, its high air leakage index results in a film with poor operability.

[0793] <Evaluation Methods>

[0794] (2-1) Intrinsic viscosity (IV) of polyester

[0795] The determination was performed using the same method as described in (1-1) above.

[0796] (2-2) Average particle size

[0797] The determination was performed using the same method as described in (1-2) above.

[0798] (2-3) The uneven structure of the resin layer

[0799] The determination was performed using the same method as described in (1-3) above.

[0800] (2-4) Arithmetic mean roughness (Ra) and ten-point mean roughness (Rzjis) of the resin layer surface

[0801] The arithmetic mean roughness (Ra) and the ten-point mean roughness (Rzjis) are calculated using the same method as described in (1-6) above.

[0802] (2-5) Support length ratio (Rmr(50)) and support length ratio (Rmr(80)) of the resin layer surface

[0803] Using the same method as (1-7) above, we can find Rmr(50) and Rmr(80).

[0804] (2-6) Arithmetic mean roughness (Sa) and maximum peak height (Sp) of the side surface opposite to the resin layer.

[0805] The arithmetic mean roughness (Sa) and maximum peak height (Sp) are calculated using the same method as described in (1-8) above.

[0806] (2-7) Static friction coefficient

[0807] The static friction coefficient between the resin layer surface and the opposite side of the laminated polyester film is determined by the same method as described in (1-9) above.

[0808] (2-8) Air Leakage Index

[0809] The air leakage index is calculated using the same method as described in (1-10) above.

[0810] (2-9) Surface resistivity

[0811] Using a high-resistivity resistivity meter (Mitsubishi Chemical Analysis Technology Co., Ltd., Hirestar UX MCP-HT 800) and a measuring probe (UR-100), after the laminated polyester film (sample) was fully conditioned in a measuring atmosphere of 23°C and 50% RH, the surface resistance (Ω / □) of the resin layer was measured after 1 minute under an applied voltage of 100V.

[0812] It should be noted that “OVER” in Table 2-2 indicates that the upper limit of measurement has been exceeded.

[0813] (2-10) Surface charge

[0814] On a glass plate, two laminated polyester films are stacked with the resin layer facing down, and pressed together twice using a rubber roller. The top film is then quickly peeled off at a 90-degree angle, and the surface charge of the resin layer is immediately measured using a Kasuga Electric Corporation KSD-1000 digital electrostatic potential meter.

[0815] Regarding the surface charge on the opposite side, the same method as described above was used, except that the film placed on the glass plate was positioned with the resin layer facing upwards.

[0816] The measurement was performed twice, and the average of the absolute values ​​was calculated.

[0817] It should be noted that the thin film was de-charged using a charge remover beforehand, and the test was conducted after confirming that the surface charge was 0kV.

[0818] The absolute value of the surface charge is preferably 9.0kV or less, more preferably 3.0kV or less, and even more preferably 1.0kV or less.

[0819] <Materials Used>

[0820] The polyesters used in the examples and comparative examples are as described above.

[0821] The resin composition obtained by stirring and mixing according to the composition shown in Table 2-1 below was diluted with water to prepare coating solutions 2-1 to 2-13. The compounds used are shown below.

[0822] [Compound (Aa): Antistatic agent (2-IA)]

[0823] An ammonium-containing polymer compound with a number average molecular weight of 30,000, synthesized from structural units of the following formula (5-2-1).

[0824]

[0825] [Compound (Aa): Antistatic agent (2-IB)]

[0826] An antistatic agent with a number average molecular weight of 50,000, formed from structural units of the following formula (5-2-2).

[0827]

[0828] [Compound (Aa): Antistatic agent (2-IC)]

[0829] A polymer compound with a number average molecular weight of 30,000 is obtained by copolymerizing the structural unit of formula (5-2-1) above with the structural unit of formula (5-2-3) below at a weight ratio of 95 / 5.

[0830]

[0831] [Compound (B): Adhesive Resin (2-IIA)]

[0832] Release agent: Add 300g of oxidized polyethylene wax with a melting point of 105℃, an acid value of 16mgKOH / g, a density of 0.93g / mL, and a number average molecular weight of 5000, 650g of deionized water, 50g of decaglycerol monooleate surfactant, and 10g of 48% potassium hydroxide aqueous solution to a 1.5L emulsification device equipped with a mixer, thermometer, and temperature controller. After purging with nitrogen, seal the device and stir at high speed at 150℃ for 1 hour. Then cool the mixture to 130℃ and pass it through a high-pressure homogenizer at 400 atmospheres. Cool the mixture to 40℃ to obtain a wax emulsion.

[0833] [Compound (B): Adhesive Resin (2-IIB)]

[0834] Release agent: 200 parts by weight of xylene and 600 parts by weight of octadecyl isocyanate were added to a four-necked flask and heated with stirring. Starting from the moment the xylene began to reflux, 100 parts by weight of polyvinyl alcohol (average degree of polymerization 500, degree of saponification 88 mol%) were added in small amounts at 10-minute intervals over approximately 2 hours. After the addition of polyvinyl alcohol was completed, the mixture was refluxed for another 2 hours to complete the reaction. The reaction mixture was cooled to approximately 80°C and then added to methanol. The reaction product precipitated as a white precipitate. This precipitate was filtered, and 140 parts by weight of xylene was added. The mixture was heated until completely dissolved, and then methanol was added again to precipitate the product. This process was repeated several times. The precipitate was then washed with methanol, dried, and pulverized to obtain the final product.

[0835] [Compound (B): Binder Resin (2-IIC)]

[0836] Polyvinyl alcohol with a saponification degree of 88 mol% and a polymerization degree of 500

[0837] [Compound (B): Adhesive Resin (2-IID)]

[0838] An aqueous dispersion of an acrylic resin polymerized as follows

[0839] An emulsified polymer of acrylic resins mainly composed of methyl methacrylate, ethyl methacrylate, ethyl acrylate, acrylonitrile, and N-hydroxymethylacrylamide (emulsifier: anionic surfactant).

[0840] [Compound (B): Binder Resin (2-IIE)]

[0841] An aqueous dispersion of an acrylic resin polymerized with the following composition

[0842] An emulsified polymer of ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-hydroxymethylacrylamide / acrylic acid = 65 / 21 / 10 / 2 / 2 (wt%) (emulsifier: anionic surfactant).

[0843] [Compound (B): Crosslinking agent (2-III)]

[0844] Melamine compound: Hexamethoxyhydroxymethylmelamine

[0845] [Compound (C): Crosslinking catalyst (2-IV)]

[0846] 2-Amino-2-methylpropanol hydrochloride

[0847] (Example 2-1)

[0848] A blend of polyester (A) and (B) in proportions of 94% and 6% by mass, respectively, was used as the outermost (surface) layer material, while polyester (A) was used solely as the intermediate layer material. The outermost and intermediate layer materials were fed to two separate extruders, melted at 285°C, and then co-extruded on cooling rollers set to 40°C with two different three-layer configurations (surface / intermediate / surface = 1 / 8 / 1 discharge ratio), allowing them to cool and solidify to obtain an unstretched sheet.

[0849] Next, the film is stretched 3.5 times its length while passing through a heated roller assembly at 85°C to produce a uniaxially stretched film. The coating weight (after drying and stretching) on ​​one side of this uniaxially stretched film is 0.06 g / m². 2The coating solution 2-1, having the composition shown in Table 2-1 below, was applied. The film was then fed into a tenter frame and stretched 4.3 times its original length in the width direction at 100°C. Following heat treatment at 235°C, a 2% relaxation treatment was performed in the width direction to obtain a laminated polyester film with a thickness of 50 μm. The evaluation results are shown in Table 2-2.

[0850] (Examples 2-2 to 2-10)

[0851] Except for using the coating liquid shown in Table 2-1, laminated polyester films were obtained in the same manner as in Example 2-1. The evaluation results are shown in Table 2-2.

[0852] (Example 2-11)

[0853] A blend of polyester (A) and polyester (C) in proportions of 87% and 13% by mass, respectively, was used as the raw material for the outermost layer (layer A) on one side. Polyester (A) was used solely as the raw material for the intermediate layer (layer B), and polyester (A) was used solely as the raw material for the outermost layer (layer C) on one side. The raw materials for layers A, B, and C were fed to three extruders, melted at 280°C, and then co-extruded on cooling rollers set to 25°C with two different three-layer configurations (outer layer / intermediate layer / outer layer = 1.6 / 27.8 / 1.6 discharge rates). After cooling and solidification, unstretched sheets were obtained.

[0854] Next, the film is stretched 3.5 times its length while passing through a heated roller assembly at 86°C to produce a uniaxially stretched film. The coating weight (after drying and stretching) on ​​one side (the surface of layer C) of this uniaxially stretched film is 0.10 g / m². 2 The coating solution 2-1, having the composition shown in Table 2-1 below, was applied. The film was then fed into a tenter frame and stretched 4.5 times its original length in the width direction at 105°C. Following heat treatment at 230°C, a 2% relaxation treatment was performed in the width direction to obtain a laminated polyester film with a thickness of 31 μm. The evaluation results are shown in Table 2-2.

[0855] (Example 2-12)

[0856] The coating liquid shown in Table 2-1 was changed to the coating amount shown in Table 2-2, and otherwise, a laminated polyester film was obtained in the same manner as in Example 2-11. The evaluation results are shown in Table 2-2.

[0857] (Example 2-13)

[0858] Using only polyester (A) as the raw material for the outermost layer (surface layer) and only polyester (D) as the raw material for the intermediate layer, a laminated polyester film was obtained in the same manner as in Examples 2-11. The evaluation results are shown in Table 2-2.

[0859] (Example 2-14)

[0860] The coating liquid shown in Table 2-1 was changed to the coating amount shown in Table 2-2, and otherwise, a laminated polyester film was obtained in the same manner as in Example 2-13. The evaluation results are shown in Table 2-2.

[0861] (Comparative Example 2-1)

[0862] Without a resin layer, a polyester film was obtained in the same manner as in Example 2-1. The evaluation results are shown in Table 2-2.

[0863] (Comparative Examples 2-2 to 2-3)

[0864] Using the coating liquid shown in Table 2-1, and changing the coating amount (after drying and stretching) to that shown in Table 2-2, a laminated polyester film was obtained in the same manner as in Example 2-1. The evaluation results are shown in Table 2-2.

[0865] (Comparative Examples 2-4)

[0866] Without a resin layer, a polyester film was obtained in the same manner as in Examples 2-11. The evaluation results are shown in Table 2-2.

[0867] (Comparative Examples 2-5)

[0868] Without a resin layer, a polyester film was obtained in the same manner as in Examples 2-13. The evaluation results are shown in Table 2-2.

[0869] (Comparative Examples 2-6)

[0870] Using the coating liquid shown in Table 2-1, and changing the coating amount (after drying and stretching) to that shown in Table 2-2, a laminated polyester film was obtained in the same manner as in Example 2-13. The evaluation results are shown in Table 2-2.

[0871] [Table 5]

[0872] Table 2-1

[0873]

[0874] [Table 6]

[0875] Table 2-2

[0876]

[0877] It should be noted that polyester film A in Table 2-2 above is the polyester film of Example 2-1, polyester film B is the polyester film of Example 2-11, and polyester film C is the polyester film of Example 2-13.

[0878] As shown in Table 2-2, Examples 2-1 to 2-10, which are laminated polyester films with antistatic properties, have formed an uneven structure by including compound (Aa) and compound (B), and the support length ratio (Rmr(80)) at a cut level of 80% is 85% or less, thus achieving a suitable uneven shape. The static friction coefficient is as low as 1.0 or less, and the film has good sliding properties, making it a film with excellent productivity such as winding properties. In addition, it can be seen that by making the surface resistivity 1×10 13 With a charge level below Ω / □, the thin film has a low charge, making it a film with minimal impact from foreign matter adhesion and secondary processing layers.

[0879] On the other hand, Comparative Example 2-1, lacking a resin layer, lacks a textured structure and has a high surface resistivity. Furthermore, Comparative Example 2-2 has a high surface resistivity, resulting in a large charge on the film surface. Moreover, Comparative Example 2-3 has a high surface resistivity, leading to a high charge on the film surface, and a support length ratio (Rmr(80)) greater than 85% at 80% of the cutting level. Therefore, it lacks a textured structure, has a high coefficient of friction, poor sliding and venting properties, and is a film with poor processability.

[0880] Furthermore, Examples 2-11 to 2-14, due to their suitable uneven structure, exhibit low static friction coefficients and air leakage indices, excellent sliding and winding properties, and are highly productive films that also reduce surface charge. In addition, the arithmetic mean roughness (Sa) and maximum peak height (Sp) of the opposite side of the resin layer are also low, making them excellent films suitable for precision processing.

[0881] On the other hand, Comparative Examples 2-4 to 2-5, like Comparative Example 2-1, lack a resin layer, resulting in a support length ratio (Rmr(80)) greater than 85% at 80% cut level. This leads to a very high air leakage index, a high static friction coefficient, and a high surface charge on the film. Consequently, they exhibit low sliding and winding properties, making them films with poor productivity. Furthermore, Comparative Example 2-6, while possessing a resin layer, lacks a textured structure and has a high support length ratio (Rmr(80)), thus lacking a suitable textured structure. Therefore, it has a high static friction coefficient and a very high air leakage index, making it a film with poor operability.

[0882] <Evaluation Methods>

[0883] (3-1) Intrinsic viscosity (IV) of polyester

[0884] The determination was performed using the same method as described in (1-1) above.

[0885] (3-2) Average particle size

[0886] The determination was performed using the same method as described in (1-2) above.

[0887] (3-3) The uneven structure of the resin layer

[0888] The determination was performed using the same method as described in (1-3) above.

[0889] (3-4) Hansen solubility parameters (HSP) of each resin [δd, δp, δh]

[0890] The determination was performed using the same method as described in (1-4) above.

[0891] (3-5) Hansen solubility parameter (HSP) distance

[0892] The determination was performed using the same method as described in (1-5) above.

[0893] (3-6) Arithmetic mean roughness (Ra) and ten-point mean roughness (Rzjis) of the resin layer surface

[0894] The arithmetic mean roughness (Ra) and the ten-point mean roughness (Rzjis) are calculated using the same method as described in (1-6) above.

[0895] (3-7) Support length ratio (Rmr(50)) and support length ratio (Rmr(80)) of the resin layer surface

[0896] Using the same method as (1-7) above, we can find Rmr(50) and Rmr(80).

[0897] (3-8) Peel force of the release layer tape

[0898] A 5cm wide adhesive tape (manufactured by Nitto Denko Co., Ltd., "No. 31B") was pressed against the surface of the release layer of the release film by reciprocating once with a 2kg rubber roller, and the peel force was measured after being left at room temperature for 1 hour. The peel force was measured using a small benchtop testing machine "EZ Graph" (manufactured by Shimadzu Corporation) at a tensile speed of 300mm / min, with 180° peeling.

[0899] (3-9) Adhesion of the release layer coating

[0900] By rubbing the release film's release layer five times by touch, determine whether the release layer has detached according to the following criteria.

[0901] Judgment Criteria

[0902] 〇: No coating peeling was observed, or the coating turned white but did not peel off.

[0903] ×: Confirmation of coating peeling

[0904] (3-10) Static friction coefficient

[0905] The static friction coefficient between the resin layer surface and the release layer surface of the release film is determined by the following method.

[0906] A film is adhered to a smooth metal plate with a width of 10 mm and a length of 100 mm, with the surface of the release layer as the upper surface. A film cut to a width of 18 mm and a length of 120 mm is placed on the plate with the surface containing the resin layer as the lower surface. A metal pin with a diameter of 8 mm is then pressed onto the film, and the metal pin is slid along the length of the glass plate under a load of 30 g and a speed of 40 mm / min to measure the frictional force. The maximum value immediately after sliding out is taken as the static friction coefficient for evaluation. It should be noted that the measurement is performed at room temperature of 23 ± 1 °C and humidity of 50 ± 0.5% RH. In addition, the number of measurements (N) is set to 3, and the average value is used.

[0907] Static friction coefficient (μs) = Fs / weight load

[0908] (In the above formula, Fs is in grams (g), and the weight load is in grams (g).)

[0909] (3-11) Air Leakage Index

[0910] The air leakage index is calculated using the same method as described in (1-10) above.

[0911] <Materials Used>

[0912] The polyesters used in the examples and comparative examples are as described above.

[0913] The resin compositions obtained by stirring and mixing according to the compositions shown in Table 3-2 below were diluted with water to prepare coating solutions 3-A1 to 3-A7. The compounds used are shown below.

[0914] [Compound (A): Low polar compound (3-I)]

[0915] In a 1.5L emulsification apparatus equipped with a mixer, thermometer, and temperature controller, 300g of oxidized polyethylene wax with a melting point of 105℃, an acid value of 16mgKOH / g, a density of 0.93g / mL, and a number average molecular weight of 5000, 650g of deionized water, 50g of decaglycerol monooleate surfactant, and 10g of 48% potassium hydroxide aqueous solution were added. After purging with nitrogen, the mixture was sealed and stirred at high speed at 150℃ for 1 hour. The mixture was then cooled to 130℃ and passed through a high-pressure homogenizer at 400 atmospheres. After cooling to 40℃, a wax emulsion was obtained.

[0916] [Compound (B): Adhesive Resin (3-IIA)]

[0917] An aqueous dispersion of an acrylic resin polymerized with the following composition

[0918] An emulsified polymer of ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-hydroxymethylacrylamide / acrylic acid = 65 / 21 / 10 / 2 / 2 (wt%) (emulsifier: anionic surfactant).

[0919] [Compound (B): Adhesive Resin (3-IIB)]

[0920] Aqueous dispersion of polyester resin copolymerized with the following composition

[0921] Monomer composition: (Acid component) Terephthalic acid / isophthalic acid / sodium isophthalic acid 5-sulfonate / / (Diol component) Ethylene glycol / 1,4-butanediol / diethylene glycol = 56 / 40 / 4 / / 70 / 20 / 10 (mol%)

[0922] [Compound (B): Adhesive Resin (3-IIC)]

[0923] An ammonium-containing polymer compound with a number average molecular weight of 30,000, synthesized from structural units of the following formula (5-3-1).

[0924]

[0925] [Compound (B): Crosslinking agent (3-III)]

[0926] Melamine compound: Hexamethoxyhydroxymethylmelamine

[0927] [Compound (C): Crosslinking catalyst (3-IV)]

[0928] 2-Amino-2-methylpropanol hydrochloride

[0929] [Compound (D): Particle (3-V)]

[0930] Silica particles with an average particle size of 0.005 μm

[0931] The HSP values ​​of each resin (3-I) to (3-III) determined by the method described in (3-4) above are shown in Table 3-1.

[0932] [Table 7]

[0933] Table 3-1

[0934]

[0935] The release agent composition obtained by mixing the components shown in Table 3-3 below was diluted with water to prepare coating solutions 3-B1 to 3-B3. The compounds used are shown below.

[0936] [Mold Release Agent (3-VIA)]

[0937] An aqueous dispersion of vinyl-containing polydimethylsiloxane with a vinyl content of 0.16 mmol / g (emulsifier: nonionic surfactant).

[0938] [Mold Release Agent (3-VIB)]

[0939] An aqueous dispersion of hydrogen-containing polydimethylsiloxane with a Si-H group content of 7.8 mmol / g (emulsifier: nonionic surfactant).

[0940] [Mold Release Agent (3-VIC)]

[0941] Compounds containing long-chain alkyl groups obtained by adding octadecyl isocyanate to polyvinyl alcohol with an average degree of polymerization of 500 and a degree of saponification of 88 mol%.

[0942] [Crosslinking agent (3-VII)]

[0943] Partially etherified melamine containing hydroxymethyl, methoxy, and imino groups

[0944] [Compounds containing (meth)acryloyl groups (3-VIII)]

[0945] An aqueous dispersion of a mixture of polycarbonate-based urethane resin and (meth)acrylate compound as described below

[0946] An aqueous dispersion of a mixture of urethane (meth)acrylate and other (meth)acrylate compounds, comprising 50 parts by weight of a polyurethane (meth)acrylate resin formed by a molecular weight of 1100 polyhexamethylene carbonate diol unit: dimethylolpropionic acid unit: hydrogenated dimethyl phthalate diisocyanate unit: dipentaerythritol pentaacrylate unit = 11:7:40:42 (mol%), 27 parts by weight of dipentaerythritol hexaacrylate, and 23 parts by weight of trimethylolpropane triacrylate.

[0947] (Example 3-1)

[0948] Polyester (A) was used as the raw material for the outermost (surface) layer, and polyester (D) was used as the raw material for the intermediate layer. The raw materials for the outermost and intermediate layers were fed to two extruders, respectively, and melted at 280°C. Then, they were co-extruded on cooling rollers set to 25°C with two different three-layer configurations (surface / intermediate / surface = 1.6 / 27.8 / 1.6 discharge rates), and then cooled and solidified to obtain an unstretched sheet.

[0949] Next, the film is stretched 3.5 times its length while passing through a heated roller assembly at 86°C to produce a uniaxially stretched film. On one side of this uniaxially stretched film, a coating amount (after drying and stretching) of 0.10 g / m is applied. 2 The coating liquid 3-A1, having the composition shown in Table 3-2 below, is applied to the opposite side of the surface at a coating amount (after drying and stretching) of 0.06 g / m. 2 The coating solution 3-B1, having the composition shown in Table 3-3, was applied. The film was then fed into a stretching machine and stretched 4.5 times its original length in the width direction at 105°C. Following heat treatment at 230°C, a 2% relaxation treatment in the width direction was performed to obtain a release film with a polyester film thickness of 31 μm. The evaluation results are shown in Table 3-4.

[0950] (Examples 3-2 to 3-14)

[0951] Using the coating liquids shown in Tables 3-2 and 3-3, and with the coating amount (after drying and stretching) set as shown in Table 3-4, the release film was obtained in the same manner as in Example 3-1. The evaluation results are shown in Table 3-4.

[0952] (Comparative Example 3-1)

[0953] The polyester film was obtained in the same manner as in Example 3-1, except that no resin layer and release layer were provided. The evaluation results are shown in Tables 3-4.

[0954] (Comparative Example 3-2)

[0955] Using the coating liquid shown in Table 3-2, and with the coating amount (after drying and stretching) set as shown in Table 3-4, and without a release layer, a polyester film with a resin layer was obtained in the same manner as in Example 3-1. The evaluation results are shown in Table 3-4.

[0956] (Comparative Example 3-3)

[0957] Using the coating liquid shown in Table 3-3, and setting the coating amount (after drying and stretching) as shown in Table 3-4, and without setting a resin layer, a polyester film with a release layer was obtained in the same manner as in Example 3-1. The evaluation results are shown in Table 3-4.

[0958] [Table 8]

[0959] Table 3-2

[0960]

[0961] [Table 9]

[0962] Table 3-3

[0963]

[0964] [Table 10]

[0965] Table 3-4

[0966]

[0967] It should be noted that in the HSP distances in Tables 3-4 above, for example, 3-I / 3-II represents the HSP distance between 3-I and 3-II. More specifically, 3-I / 3-II in Example 3-1 refers to the HSP distance between the low polarity compound (3-I) and the binder resin (3-IIA).

[0968] As shown in Table 3-4, Examples 3-1 to 3-14, as release films, contain compounds (A) and (B) and have a support length ratio (Rmr(80)) of 94% or less at a cut level of 80%, thus achieving a suitable uneven shape, a static friction coefficient as low as 1.0 or less, good sliding properties, an air leakage index of 150,000 seconds or less, and excellent venting properties. Therefore, they are films with excellent productivity, such as winding properties.

[0969] Industrial availability

[0970] The laminated polyester film of the present invention has a fine uneven structure on the surface of the resin layer, and therefore has the following advantages, for example, when used for sheet forming: it also exhibits good rollability when the extremely smooth film is rolled into a roll and is not prone to wrinkling.

[0971] Furthermore, since the laminated polyester film of the present invention can make the resin layer a thin film, it can also cope with the elongation of the polyester film, which can help improve productivity by reducing the frequency of product roll switching during processing.

[0972] Therefore, the laminated polyester film of the present invention can be suitably used as a sheet-forming polyester film with excellent surface smoothness, etc., and has high industrial application value.

[0973] Furthermore, the laminated polyester film with antistatic properties of the present invention has the following advantages when used for sheet forming, for example, because the surface of the resin layer has a fine uneven structure: it also exhibits good rollability when the extremely smooth film is rolled into a roll and is not prone to wrinkling.

[0974] Furthermore, the laminated polyester film with antistatic properties of the present invention has the following advantages when used, for example, for sheet forming, because the surface resistance of the resin layer is low: it can suppress surface charging of the film and prevent the adhesion of foreign matter, thereby preventing defects during processing that takes advantage of the high smoothness of the film surface.

[0975] Furthermore, the antistatic laminated polyester film of the present invention, since it enables the resin layer to be a thin film, can also cope with the elongation of polyester film, which can help improve productivity by reducing the frequency of product roll switching during processing.

[0976] Therefore, the laminated polyester film with antistatic properties of the present invention can be suitably used as a sheet-forming polyester film with excellent surface smoothness, etc., and has high industrial application value.

[0977] Furthermore, the resin layer surface of the release film of the present invention has a fine uneven structure, thus having the following advantages, for example, when used for sheet forming: it also exhibits good rollability when rolling an extremely smooth film into a roll, and is not prone to wrinkles.

[0978] Furthermore, since the release film of the present invention can make the resin layer into a thin film, it can also cope with the elongation of the release film, which can help improve productivity by reducing the frequency of product roll switching during processing.

[0979] Therefore, the release film of the present invention can be suitably used as a release film for sheet forming with excellent surface smoothness, etc., and has high industrial application value.

Claims

1. A laminated polyester film comprising a polyester film and a resin layer formed of a resin composition, the resin layer being formed on at least one side of the polyester film, the laminated polyester film satisfying all of the following conditions (1) to (3). (1) The resin layer has an uneven structure; (2) The resin composition comprises the following compounds (A) and (B); (A) A low-polarity compound, wherein the low-polarity compound is a mold release agent. (B) Adhesive resin and crosslinking agent, (3) When measured using a scanning probe microscope, the bearing length ratio Rmr80 of the roughness curve at 80% of the cut level of the resin layer surface is less than 76%. in, The term "uneven structure" refers to a cross-sectional shape with a width of 25 μm observed using a scanning probe microscope. In this case, over 80% of the cross-sections show multiple protrusions or depressions with a height difference exceeding 10 nm. The coating amount of non-volatile components in the resin layer is 0.005–0.95 g / m². 2 .

2. The laminated polyester film according to claim 1, wherein, When measured using a scanning probe microscope, the bearing length ratio Rmr50 of the roughness curve at a cut level of 50% of the resin layer surface is less than 60%.

3. The laminated polyester film according to claim 1 or 2, wherein, When measured using a scanning probe microscope, the arithmetic mean roughness Ra of the resin layer surface is 20 nm or more and 600 nm or less.

4. The laminated polyester film according to claim 1 or 2, wherein, The ten-point average roughness Rzjis of the resin layer surface, measured using a scanning probe microscope, is above 70 nm and below 800 nm.

5. The laminated polyester film according to claim 1 or 2, wherein the air leakage index is less than 130,000 seconds.

6. The laminated polyester film according to claim 1 or 2, wherein, The low-polarity compound comprises one or more compounds selected from the group consisting of waxes and compounds containing long-chain alkyl groups.

7. The laminated polyester film according to claim 1 or 2, wherein, The adhesive resin comprises one or more selected from the group consisting of (meth)acrylic resins, polyvinyl alcohol, and ionicly conductive polymers.

8. The laminated polyester film according to claim 1 or 2, wherein, The crosslinking agent comprises one or more compounds selected from the group consisting of melamine compounds and oxazoline compounds.

9. The laminated polyester film according to claim 1 or 2, wherein, The resin composition contains a crosslinking catalyst as compound (C).

10. The laminated polyester film according to claim 1 or 2, wherein, The resin composition contains microparticles as compound (D).

11. The laminated polyester film according to claim 1 or 2, which is used as a support for the ceramic green sheet in the manufacturing process of the laminated ceramic capacitor.

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