Laminated polyester film

Abstract

To provide a laminated polyester film having excellent peelability.SOLUTION: A laminated polyester film has a resin layer on at least one surface of a substrate film, wherein the substrate film is a resin film including a polyester, has a thickness of lower than 15 μm, and includes a particle. The resin layer has a convex projection derived from the particle, and, when thickness of the substrate film is denoted as A(μm) and height of the convex projection is denoted as B(μm), the laminated polyester film satisfies the following relational expression (1). 0.10≤B / A<0.23 (1) (here, the height B of the convex projection is a height from the lowest portion of the surface of the resin layer to an apex of the convex projection).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminated polyester film, and more particularly to a laminated polyester film having a resin layer on at least one side. [Background technology]

[0002] Polyester films are used in a wide range of fields due to their excellent transparency, optical properties, dimensional stability, mechanical strength, heat resistance, chemical resistance, and electrical properties. Specifically, they are used as magnetic recording materials, packaging materials, solar cells, separators for liquid crystal polarizers, substrates for dry film resists, release films for forming green sheets for multilayer ceramic capacitors, as well as optical films such as anti-reflective films, diffusion sheets, and prism sheets, and films for label printing.

[0003] These polyester films, which are used in a wide range of applications, can be used as protective films for adhesive sheets with protective films (which have a protective film / resin composition layer / support) used in the build-up method, one of the semiconductor manufacturing processes. However, conventional polyester films had a problem in that when the protective film was peeled off, a portion of the resin composition layer would also be peeled off along with the protective film (hereinafter sometimes simply referred to as "resin peeling"). For example, Patent Document 1 discloses an adhesive sheet with a protective film, comprising an adhesive sheet consisting of a support and a resin composition layer bonded to the support, and a protective film provided to bond to the resin composition layer of the adhesive sheet, wherein the resin composition layer contains an inorganic filler and a thermosetting resin, the content of the inorganic filler in the resin composition layer is 60% by mass or more when the non-volatile components in the resin composition layer are taken as 100% by mass, and the peel strength of the support to the resin composition layer (SA) and the peel strength of the protective film to the resin composition layer (SB) satisfy SA-SB≧0.0020 [kgf / cm], and a polyethylene terephthalate film with a thickness of 25 μm is used as the protective film (see Example 2).

[0004] Furthermore, Patent Document 2 discloses an adhesive sheet with a protective film, which includes an adhesive sheet comprising a support having first and second surfaces and a resin composition layer bonded to the second surface of the support, and a protective film having first and second surfaces and provided such that the second surface is bonded to the resin composition layer of the adhesive sheet, wherein the arithmetic mean roughness (Rap1) of the first surface of the protective film, measured in accordance with JIS B 0601, is 100 nm or more, and the arithmetic mean roughness (Rap2) of the second surface of the protective film, measured in accordance with JIS B 0601, is 100 nm or more. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2014-24961 [Patent Document 2] Japanese Patent Publication No. 2016-20480 [Overview of the project] [Problems that the invention aims to solve]

[0006] In the adhesive sheets with protective films disclosed in the above-mentioned Patent Documents 1 and 2, the adhesion between the support and the resin composition layer is relatively higher than the adhesion between the protective film and the resin layer to prevent the resin from peeling off during removal. However, depending on the formulation, type, and modification of the resin composition layer, the adhesion between the protective film and the resin composition layer may become too strong, potentially leading to problems such as poor peelability. Therefore, the object of the present invention is to provide a laminated polyester film with excellent release properties. [Means for solving the problem]

[0007] The polyester film of the present invention has the following configuration in order to solve the above problems.

[0008] [1] A laminated polyester film having a resin layer on at least one surface of a base film, wherein the base film is a resin film containing polyester, has a thickness of less than 15 μm, and contains particles, the resin layer has convex protrusions derived from the particles, and when the thickness of the base film is A (μmm) and the height of the convex protrusions is B (μm), the following relation (1) is satisfied. 0.10 ≤ B / A < 0.23 ···(1) (However, the height B of the convex protrusion refers to the height from the lowest part of the resin layer's surface to the apex of the convex protrusion.)

[0009] [2] The laminated polyester film described in [1] above, wherein the average particle diameter of the particles is C (μm), and the following relation (2) is satisfied. 0.25

[0010] [3] The laminated polyester film according to [1] or [2] above, wherein the intrinsic viscosity of the resin film is 0.50 dl / g or more.

[0011] [4] A laminated polyester film according to any one of the above [1] to [3], wherein the average particle size of the particles is 1 to 10 μm.

[0012] ​[5] The resin layer is the laminated polyester film according to any one of the above [1] to [4], which contains a non-silicone-based release agent. [6] The non-silicone-based release agent contains a long-chain alkyl group-containing compound, and the laminated polyester film according to [5] above.

[0013] [7] The resin layer is formed from a resin composition containing a crosslinking agent, and the laminated polyester film according to any one of the above [1] to [6].

[0014] [8] The crosslinking agent is a melamine-based compound, and the laminated polyester film according to [7] above.

[0015] [9] The 180° peel strength of the resin layer is 30 to 330 mN / cm, and the laminated polyester film according to any one of the above [1] to [8].

[0016]

[10] An adhesive sheet with a protective film, which has an adhesive sheet and a protective film, and the protective film is the laminated polyester film according to any one of the above [1] to [9].

[0017]

[11] The adhesive sheet has a support and a resin composition layer formed on at least one surface of the support, and the adhesive sheet with a protective film according to

[10] above.

[0018]

[12] An adhesive sheet with a protective film for a build-up layer of a printed wiring board, and the adhesive sheet with a protective film according to

[10] or

[11] above.

[0019]

[13] The adhesive sheet with a protective film according to any one of the above

[10] to

[12] is a roll-shaped adhesive sheet with a protective film wound in a roll. [Advantages of the Invention]

[0020] According to the present invention, a laminated polyester film excellent in peelability can be provided. [Brief Description of the Drawings]

[0021] [Figure 1] Figure 1 is a cross-sectional view of the polyester film of the present invention (Example 1). [Modes for carrying out the invention]

[0022] <Laminated polyester film> The laminated polyester film of the present invention (hereinafter also referred to as "this film") has a resin layer on at least one surface of a base film, and the base film is a resin film containing polyester.

[0023] Preferably, the base film contains particles, and the resin layer has convex protrusions derived from the particles. Furthermore, the thickness of the base film is preferably less than 15 μm, preferably 13 μm or less, more preferably 12 μm or less, even more preferably 11 μm or less, and most preferably 10 μm or less. If the thickness of the base film is less than 15 μm and the base film has convex protrusions, the risk of breakage is normally high. However, because the thickness of the base film and the height of the convex protrusions have the relationship shown in the following relation (1), this film is thin but does not have the risk of breakage.

[0024] In other words, it is preferable that the present film satisfies the following relation (1), where A (μm) is the thickness of the base film and B (μm) is the height of the convex protrusions originating from the particles in the base film. 0.10 ≤ B / A < 0.23 ···(1) By satisfying the relationship (1) above, the particles are appropriately embedded in the base film and appropriately protruding from the base film, creating convex protrusions on the resin layer. Therefore, there is no risk of the particles being too embedded and resulting in poor peelability, nor is there a risk of the base film breaking, thus achieving excellent peelability. From this perspective, it is more preferable that relation (1) is 0.10 ≤ B / A ≤ 0.22, and even more preferable that it is 0.12 ≤ B / A ≤ 0.20. Furthermore, "convex protrusion" refers to a convex protrusion formed by particles contained in the base film protruding from the surface of the base film, and "convex protrusion height B (μm)" refers to the height from the lowest part of the resin layer surface to the apex of the convex protrusion.

[0025] For this film to have a surface state that satisfies the above relation (1), the average particle size and content of particles, film-forming conditions such as stretching conditions (for example, increasing the stretching ratio to make the convex protrusions more prominent), and the thickness of the resin layer relative to the base film can be appropriately adjusted. Furthermore, by constructing the base film in a multilayer structure and increasing the thickness of the surface layer, which is the particle-containing layer, relative to the overall thickness of the base film, the amount of protrusion of the convex protrusions can be adjusted. Furthermore, the amount of protrusion of the convex protrusions can also be adjusted by appropriately adjusting the intrinsic viscosity (IV) of the base film to increase its fluidity.

[0026] Furthermore, from a similar viewpoint, it is preferable that the film satisfies the following relation (2), where B (μm) is the height of the convex protrusions originating from the particles in the base film and C (μm) is the average particle diameter of the particles in the base film. 0.25 By satisfying the aforementioned relation (2), there is no risk of the particles becoming too embedded and thus having poor peelability, nor is there a risk of the particles falling off, thus achieving excellent peelability. From this perspective, relation (2) is 0.25

[0027] <particle> ​​The types of particles are not particularly limited and include, for example, inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenolic resin, epoxy resin, and benzoguanamine resin. Furthermore, precipitated particles obtained by precipitating and finely dispersing a portion of metal compounds such as catalysts during the polyester manufacturing process can also be used. Among these, silica particles and calcium carbonate particles are particularly preferred because they are effective even in small quantities.

[0028] Furthermore, there are no particular limitations on the shape of the particles used; spherical, lumpy, rod-shaped, flattened, or crushed particles may be used. Of these, spherical or crushed particles are preferred from the viewpoint of easily satisfying formulas (1) and (2) and stably generating convex protrusions. Furthermore, there are no particular restrictions on their hardness, specific gravity, color, etc. Two or more types of these particles may be used in combination as needed.

[0029] Furthermore, the average particle diameter of the particles is preferably in the range of 1 to 10 μm, more preferably in the range of 1 to 8 μm, even more preferably in the range of 2 to 6 μm, and particularly preferably in the range of 2 to 5 μm, from the viewpoint of obtaining the height B (μm) of the convex protrusions. Furthermore, if the particles are in powder form, the average particle size can be determined by measuring the powder using a laser diffraction particle size distribution analyzer (for example, the SALD-2000J model manufactured by Shimadzu Corporation) and using the average value obtained.

[0030] Furthermore, the particle content in the base film is preferably in the range of 0.1 to 10% by mass relative to the total polyester constituting the base film, in the case of a single-layer film. If the particle content is 0.1% by mass or more, sufficient peelability is obtained, and if it is 10% by mass or less, the transparency of the base film is ensured. From the above viewpoint, the particle content in the base film is more preferably in the range of 1 to 10% by mass, even more preferably 1.2 to 5% by mass, and particularly preferably 1.5 to 3% by mass.

[0031] Furthermore, if the base film is a multilayer film, it is sufficient to include the particles in the surface layer. For example, by using a base film that contains particles only in the surface layer, it is possible to form a surface state that satisfies the above relational equations (1) and / or (2) while avoiding a decrease in transparency due to the particles. From the viewpoint of release properties and transparency of the base film, when the base film is multilayered, the particle content in the surface layer (when the entire surface layer constituent material is considered as 100%) is preferably in the range of 0.1 to 10% by mass, more preferably 1 to 10% by mass, even more preferably 1.2 to 5% by mass, and particularly preferably 1.5 to 3% by mass. The average particle size is the same as that of the particles in the single-layer case described above.

[0032] The method for adding particles to the base film is not particularly limited, and conventionally known methods can be employed. For example, the particles can be added at any stage in the production of polyester, but preferably, the particles may be added at the esterification stage or after the completion of the transesterification reaction to proceed with the polycondensation reaction. Alternatively, the process may be carried out by using a vented kneading extruder to blend a slurry of particles dispersed in ethylene glycol or water with a polyester raw material, or by using a kneading extruder to blend dried particles with a polyester raw material.

[0033] In addition to the particles mentioned above, conventionally known antioxidants, heat stabilizers, lubricants, antistatic agents, fluorescent whitening agents, dyes, pigments, etc., may be added to the base film as needed. Furthermore, the product may contain ultraviolet absorbers, particularly benzoxazinon-based ultraviolet absorbers.

[0034] <Base film> A resin film containing polyester is particularly preferred as the base film. Resin films containing polyester have excellent physical properties such as heat resistance, flatness, optical properties, and strength, and in particular, even when thin, their mechanical properties (stiffness and softness) are superior to those of polyolefin films, making it possible to create thin films. Preferably, the resin film has polyester as the component that accounts for the largest mass ratio among the resin components constituting the resin film, more preferably 50% by mass or more of the resin components constituting the resin film is polyester, more preferably 55% by mass or more, even more preferably 60% by mass or more, even more preferably 75% by mass or more, and most preferably 85% by mass or more. Furthermore, the aforementioned resin film may be a mixture of other resins besides polyester, such as polyethylene, polypropylene, cycloolefin polymer (COP), polystyrene, acrylic resin, polycarbonate, polyurethane, triacetylcellulose (TAC), polyvinyl chloride, polyethersulfone, polyamide, polyimide, polyamideimide, etc. (polymer blend) or a composite of constituent units (polymer), as long as it can be formed into a film.

[0035] The above-mentioned resin film may be a single-layer structure consisting of a single layer containing polyester (hereinafter also referred to as the "polyester layer"), or a multi-layer structure containing two or more polyester layers. It may also be a multi-layer structure of four or more layers, in addition to two or three layers, and is not particularly limited. It is preferable to have a multi-layer structure of two or more layers, giving each layer its own characteristics to achieve multi-functionality. Specific configurations include polyester layer (A) / polyester layer (B), polyester layer (A) / polyester layer (B) / polyester layer (A), and so on. Furthermore, other combinations such as polyester layer (A) / polyester layer (B) / polyester layer (C), polyester layer (A) / polyester layer (B) / polyester layer (C) / polyester layer (A) can also be mentioned. However, this is not limited to these examples.

[0036] The polyester used in the above resin film is preferably one obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, trimethylene glycol, tetramethylene glycol, neopentyl glycol, and 1,4-cyclohexanedimethanol.

[0037] Typical polyesters include, for example, polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), and polybutylene terephthalate. Such polyesters may be homopolymers that are not copolymerized, or copolymerized polyesters in which 20 mol% or less of the dicarboxylic acid component is a dicarboxylic acid component other than the main component, and / or 20 mol% or less of the diol component is a diol component other than the main component. Alternatively, a mixture thereof may also be used.

[0038] Polyesters can be obtained by conventionally known methods, such as directly obtaining low-molecular-weight polyesters by reacting dicarboxylic acids and diols, or by reacting lower alkyl esters of dicarboxylic acids with diols using conventionally known transesterification catalysts, followed by a polymerization reaction in the presence of a polymerization catalyst. As the polymerization catalyst, known catalysts such as antimony compounds, germanium compounds, and titanium compounds may be used, but it is preferable to use an antimony compound with an amount of zero or 100 ppm or less as antimony, as this results in a film with reduced dullness.

[0039] Furthermore, when using a titanium compound as a catalyst, the amount of metal remaining in the film is small, which is preferable from the viewpoint of film transparency and reduction of foreign matter generation.

[0040] Furthermore, the base film can be manufactured using various conventionally known methods such as co-extrusion. In this case, the thickness of the surface layer (outermost layer) is preferably 1 μm or more, more preferably 2 μm or more, and is preferably 1 / 8 or less of the total thickness, measured on only one side. By using the material within the above range, even when a substrate film containing particles only on the surface is manufactured as described above, it is possible to create sufficient surface irregularities while avoiding a decrease in transparency due to the particles.

[0041] In this film, the 180° peel force (peel force of the resin layer) D on the resin layer side surface of the base film on which the resin layer is formed is preferably 30 to 330 mN / cm, more preferably 40 to 300 mN / cm, even more preferably 45 to 250 mN / cm, even more preferably 50 to 200 mN / cm, and particularly preferably 55 to 170 mN / cm. By keeping the 180° peel strength D of this film within the above range, the peeling force is neither too heavy (not too weak) nor too light (not too strong), resulting in appropriate peelability and reducing the likelihood of resin delamination. Conventional polyolefin films, such as conventional biaxially oriented polypropylene films, have a problem where improved adhesive strength of the adhesive sheet leads to excessively low release properties. However, this film, due to its specific surface condition, maintains excellent release properties even when the adhesive strength is improved, regardless of the adhesive material of the adhesive sheet. Furthermore, compared to conventional polyolefin films, this film is less prone to softening during lamination, making it easier to maintain release properties when bonded to adhesive sheets.

[0042] The base film preferably has an intrinsic viscosity of 0.50 dl / g or more. If the intrinsic viscosity of the base film is 0.50 dl / g or higher, it can be stretched without breaking, especially when the stretching ratio, particularly the stretching ratio in the width direction (transverse direction), is increased to 3.5 times or more, even when the thin film is formed. From this viewpoint, the intrinsic viscosity of the base film is more preferably 0.55 dl / g or higher, and even more preferably 0.57 dl / g or higher. On the other hand, there is no particular upper limit, but from the viewpoint of concerns about excessive pressure increase in the extruder, it is preferably 0.67 dl / g or lower, and even more preferably 0.65 dl / g or lower. The intrinsic viscosity of the base film can be adjusted by appropriately changing the polymerization conditions of the polyester raw material. For example, the intrinsic viscosity can be increased by increasing the molecular weight through methods such as extending the polymerization time or employing solid-phase polymerization. Note that the above-mentioned intrinsic viscosity refers to the intrinsic viscosity of the entire base film layer.

[0043] This film may be an unoriented film (sheet) or an oriented film. It is preferably an oriented film, and more preferably a biaxially oriented film. If the laminated polyester film is a biaxially oriented film, it may be a sequentially secondary-oriented film or a simultaneously biaxially oriented film. Stretching allows for easy thinning and facilitates the formation of convex protrusions.

[0044] (Method of manufacturing the base film) The following will provide a detailed explanation of the method for manufacturing the base film, but it is not limited to the following examples. First, polyester chips, either dried or undried by known methods, are supplied to a melt extruder and heated to a temperature above the melting point of each polymer to melt them. Next, the molten polymer is extruded from the die and rapidly cooled and solidified on a rotating cooling drum to a temperature below the glass transition temperature to obtain a substantially amorphous, unoriented sheet. In this case, it is preferable to improve the adhesion between the sheet and the rotating cooling drum in order to improve the flatness of the sheet, and in the present invention, electrostatic application adhesion and / or liquid coating adhesion are preferably employed.

[0045] From the viewpoint of film strength, it is preferable to stretch the sheet obtained as described above in two axes to form a film. Specifically regarding the stretching conditions, it is preferable to stretch the unstretched sheet 2.0 to 4.5 times in the longitudinal direction at 70 to 145°C to form a longitudinally uniaxially oriented film, then stretch it 3.0 to 6.5 times in the transverse direction at 90 to 160°C to form a biaxially oriented film, and then heat treat (heat fixation) it at 210 to 260°C for 10 to 600 seconds. Furthermore, it is preferable to allow 1-10% relaxation in the vertical and / or horizontal directions in the highest temperature zone of the heat treatment and / or the cooling zone at the heat treatment outlet. Among the above conditions, from the viewpoint of increasing the stretching ratio and causing convex protrusions to protrude from the base film, it is particularly preferable to stretch the film 3.4 to 4.1 times in the longitudinal direction to create a longitudinally uniaxially oriented film, and then stretch it 3.2 to 4.3 times in the transverse direction.

[0046] In particular, when using the material for applications where it is important to minimize heat shrinkage, the heat treatment temperature is preferably 215 to 250°C, more preferably 220 to 245°C, and even more preferably 230 to 245°C. By using this temperature range, it is possible to minimize heat shrinkage as much as possible.

[0047] <Resin layer> In this film, the resin layer may be provided on at least one side (one side) of the base film, or it may be provided on both sides (both sides). The aforementioned resin layer not only provides protection for various objects and prevents contamination of the protective film, but also contributes to improving the handling of the film. For example, when this film is stacked in sheets or wound into a roll, the resin layer has effects such as preventing adhesion to the adhesive layer on the back side, facilitating peeling, improving slipperiness, making it easier to manufacture the film, improving handling, and improving the processability of the adhesive layer on the film.

[0048] The amount of resin layer applied (after drying) is preferably 0.001 to 3 g / m², from the viewpoint of excellent appearance, water repellency, and release properties (prevention of adhesion to the adhesive layer). 2 , more preferably 0.005~2g / m 2 More preferably 0.010 to 1 g / m 2 It is within the range of [the specified range].

[0049] (Release agent) The resin layer, that is, the resin composition for forming the resin layer (hereinafter also referred to as the "resin layer forming resin composition"), preferably contains a mold release agent. Examples of the release agent include long-chain alkyl group-containing compounds, fluorine compounds, silicone compounds, and waxes. Among these, non-silicone release agents such as long-chain alkyl group-containing compounds, fluorine compounds, and waxes are preferred because they have less contamination in the sense of transferring to the object to be protected. Furthermore, among the non-silicone mold release agents, long-chain alkyl group-containing compounds are preferred when the resin composition layer used as the adherend, as described below, contains epoxy resin, due to their excellent release properties. These release agents may be used individually or in combination.

[0050] (Long-chain alkyl group-containing compounds) The aforementioned long-chain alkyl group-containing compound is a compound having a linear or branched alkyl group with typically 6 or more carbon atoms, preferably 8 or more, and more preferably 12 or more. The upper limit of the number of carbon atoms is not particularly limited, but is, for example, 30. Examples of alkyl groups include hexyl, octyl, decyl, lauryl, octadecyl, and behenyl groups. Examples of compounds having alkyl groups include various long-chain alkyl group-containing polymer compounds, long-chain alkyl group-containing amine compounds, long-chain alkyl group-containing ether compounds, and long-chain alkyl group-containing quaternary ammonium salts. Polymer compounds are preferable when considering heat resistance and stain resistance. Furthermore, polymer compounds having long-chain alkyl groups as side chains are more preferable from the viewpoint of effectively obtaining release properties.

[0051] Polymer compounds having long-chain alkyl groups as side chains can be obtained by reacting a polymer having a reactive group with a compound having an alkyl group that can react with the reactive group. Examples of the reactive groups include hydroxyl groups, amino groups, carboxyl groups, and acid anhydrides. Examples of compounds having these reactive groups include polyvinyl alcohol, polyethyleneimine, polyethyleneamine, reactive group-containing polyester resin, and reactive group-containing poly(meth)acrylic resin. Among these, polyvinyl alcohol is preferred considering its release properties and ease of handling.

[0052] Compounds having alkyl groups that can react with the reactive group include, for example, long-chain alkyl group-containing isocyanates such as hexyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate, and behenyl isocyanate; long-chain alkyl group-containing acid chlorides such as hexyl chloride, octyl chloride, decyl chloride, lauryl chloride, octadecyl chloride, and behenyl chloride; long-chain alkyl group-containing amines; and long-chain alkyl group-containing alcohols. Among these, long-chain alkyl group-containing isocyanates are preferred, and octadecyl isocyanate is particularly preferred, considering release properties and ease of handling.

[0053] Furthermore, polymer compounds having long-chain alkyl groups as side chains can also be obtained by polymerization of long-chain alkyl (meth)acrylates or by copolymerization of long-chain alkyl (meth)acrylates with other vinyl group-containing monomers. Examples of long-chain alkyl (meth)acrylates include hexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, octadecyl (meth)acrylate, and behenyl (meth)acrylate.

[0054] (Crosslinking agent) The resin layer-forming resin composition preferably contains various crosslinking agents in order to strengthen the resin layer and stabilize properties such as water repellency.

[0055] Various known crosslinking agents can be used as the aforementioned crosslinking agent, including, for example, melamine compounds, oxazoline compounds, epoxy compounds, isocyanate compounds, carbodiimide compounds, and silane coupling compounds. Among these, melamine compounds are preferably used from the viewpoint of improving the durability of the resin layer. The crosslinking agent may be used alone or in combination of two or more types.

[0056] The melamine-based compound refers to a compound having a melamine skeleton, and examples include alkylolated melamine derivatives, compounds partially or completely etherified by reacting alkylolated melamine derivatives with alcohol, and mixtures thereof. Suitable alcohols for etherification include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, and isobutanol. Furthermore, the melamine compound may be a monomer or a polymer of two or more units, or a mixture thereof may be used. Considering the reactivity with various compounds, it is preferable that the melamine compound contains a hydroxyl group. Furthermore, it is possible to use melamine in which urea or other substances have been co-condensed with a portion of the melamine, and it is also possible to use a catalyst to increase the reactivity of melamine-based compounds.

[0057] Furthermore, the crosslinking agent described above should be designed to react during the drying and film-forming processes to improve the performance of the resin layer. It is presumed that unreacted crosslinking agents, reacted compounds, or mixtures thereof are present in the formed resin layer.

[0058] In the resin composition for forming the resin layer, the content of the crosslinking agent is preferably in the range of 3 to 50% by mass, more preferably 5 to 40% by mass, and even more preferably 10 to 30% by mass, relative to the non-volatile components in the resin composition for forming the resin layer. By setting the content to 3% by mass or more, the effects of incorporating the crosslinking agent are more easily exhibited. Furthermore, by limiting the amount to 50% by mass or less, a certain amount or more of the long-chain alkyl group-containing compound can be incorporated into the resin composition for resin layer formation, thereby maintaining excellent mold release properties.

[0059] (Various polymers) The resin composition for forming the resin layer may also contain various polymers (also called binder resins) such as polyester resin, acrylic resin, urethane resin, and vinyl resin to improve the appearance and transparency of the coating, and to control water repellency and slipperiness. From the viewpoint of being able to easily control water repellency among various polymers, one or more selected from the group consisting of polyester resin, acrylic resin, urethane resin, and vinyl resin is preferred, and one or more selected from the group consisting of polyester resin and acrylic resin is more preferred.

[0060] The aforementioned polyester resins include, for example, those composed of polycarboxylic acids and polyhydroxy compounds as their main constituent components. In other words, as polycarboxylic acids, for example, terephthalic acid, isophthalic acid, orthophthalic 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, 2-potassium sulfoterephthalic acid, 5-sodium sulfisoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutaric acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid, monopotassium salt of trimellitic acid, and their ester-forming derivatives can be used. Furthermore, examples of the polyvalent hydroxy compounds that can be used include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanedimethylol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, potassium dimethylolpropionate, and the like. From these compounds, one or more can be appropriately selected, and a polyester resin can be synthesized by a conventional polycondensation reaction.

[0061] The aforementioned acrylic resin is a polymer composed of polymerizable monomers, including acrylic and methacrylic monomers (hereinafter, acrylic and methacrylic may be collectively abbreviated as (meth)acrylic). These can be homopolymers, copolymers, or copolymers with polymerizable monomers other than acrylic and methacrylic monomers.

[0062] Furthermore, copolymers of these polymers with other polymers (e.g., polyester, polyurethane, etc.), such as block copolymers and graft copolymers, are also included. Alternatively, polymers (and possibly mixtures of polymers) obtained by polymerizing polymerizable monomers in a polyester solution or polyester dispersion are also included. Similarly, polymers (and possibly mixtures of polymers) obtained by polymerizing polymerizable monomers in a polyurethane solution or polyurethane dispersion are also included. In the same manner, polymers (and possibly mixtures of polymers) obtained by polymerizing polymerizable monomers in other polymer solutions or dispersions are also included.

[0063] Examples of polymerizable monomers include various carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid, and their salts; various hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, monobutyl hydroxyl fumarate, and monobutyl hydroxyitaconate; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate. Examples include various (meth)acrylic acid esters such as t; various nitrogen-containing compounds such as (meth)acrylamide, diacetone acrylamide, N-methylolacrylamide, or (meth)acrylonitrile; various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, and vinyltoluene; various vinyl esters such as vinyl propionate and vinyl acetate; various silicon-containing polymerizable monomers such as γ-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane; phosphorus-containing vinyl monomers; various vinyl halides such as vinyl chloride and pyridene chloride; and various conjugated dienes such as butadiene.

[0064] The aforementioned urethane resin refers to a polymer compound having urethane bonds within its molecule. Urethane resins are typically produced by the reaction of a polyol with an isocyanate. Examples of polyols include polycarbonate polyols, polyester polyols, polyether polyols, polyolefin polyols, and acrylic polyols. These compounds may be used individually or in combination.

[0065] Polycarbonate polyols are obtained from polyhydric alcohols and carbonate compounds by a de-alcoholization reaction. Examples of the aforementioned polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 3,3-dimethylolheptane. Examples of the carbonate compounds include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and ethylene carbonate. Examples of polycarbonate polyols obtained from these reactions include poly(1,6-hexylene) carbonate and poly(3-methyl-1,5-pentylene) carbonate.

[0066] Examples of the polyester polyols include polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their acid anhydrides and polyhydric alcohols (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, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2 Examples of substances obtained from the reaction of (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, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyldialkanolamines, lactonediols, etc.) are examples.

[0067] Examples of the aforementioned polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol.

[0068] Examples of polyisocyanate compounds used to obtain the aforementioned urethane resin include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylenediphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate; aliphatic diisocyanates having aromatic rings such as α,α,α',α'-tetramethylxylylene 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 may be used individually or in combination of multiple types.

[0069] A chain extender may be used when synthesizing the aforementioned urethane resin. The chain extender is not particularly limited as long as it has two or more active groups that react with isocyanate groups. Generally, chain extenders having two hydroxyl groups or amino groups can be used.

[0070] Examples of the chain extender having two hydroxyl groups include glycols such as aliphatic glycols like ethylene glycol, propylene glycol, and butanediol, aromatic glycols like xylylene glycol and bishydroxyethoxybenzene, and ester glycols like neopentyl glycol hydroxypivalate. Furthermore, examples of chain extenders having two amino groups include aromatic diamines such as tolylenediamine, xylylenediamine, and diphenylmethanediamine; aliphatic diamines such as ethylenediamine, propylenediamine, hexanediamine, 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, isopropylidenecyclohexyl-4,4'-diamine, 1,4-diaminocyclohexane, and 1,3-bisaminomethylcyclohexane.

[0071] The aforementioned urethane resin may use a solvent as a medium, but preferably water as a medium. Methods for dispersing or dissolving the urethane resin in water include forced emulsification using an emulsifier, self-emulsification by introducing hydrophilic groups into the urethane resin, and water-soluble methods. In particular, the self-emulsification type, in which ionic groups are introduced into the structure of the urethane resin to form an ionomer, is preferred because it offers excellent storage stability of the liquid and superior water resistance and transparency of the resulting resin layer.

[0072] Furthermore, various ionic groups can be introduced, such as carboxyl groups, sulfonic acids, phosphoric acid, phosphonic acid, and quaternary ammonium salts, but carboxyl groups are preferred. Various methods can be used to introduce carboxyl groups into urethane resin at each stage of the polymerization reaction. For example, one method is to use a resin containing carboxyl groups as a copolymer component during prepolymer synthesis, or to use a component containing carboxyl groups as one component of polyols, polyisocyanates, or chain extenders. In particular, a method using a carboxyl group-containing diol to introduce a desired amount of carboxyl groups by adjusting the amount of this component added is preferred. For example, dimethylolpropionic acid, dimethylolbutanoic acid, bis-(2-hydroxyethyl)propionic acid, bis-(2-hydroxyethyl)butanoic acid, etc., can be copolymerized with the diol used in the polymerization of urethane resin. Furthermore, it is preferable that these carboxyl groups be in the form of salts obtained by neutralization with ammonia, amines, alkali metals, inorganic alkalis, etc. Ammonia, trimethylamine, and triethylamine are particularly preferred.

[0073] In such polyurethane resins, the carboxyl groups that have been removed by the neutralizing agent during the drying process after coating can be used as crosslinking reaction sites by other crosslinking agents. This results in excellent stability in the liquid state before coating, and further improves the durability, solvent resistance, water resistance, and blocking resistance of the resulting resin layer.

[0074] (Antistatic agent) Furthermore, it is also preferable to include an antistatic agent in the resin composition for forming the resin layer, thereby preventing defects such as adhesive buildup due to film peeling or triboelectric charging, as well as the adhesion of surrounding dust and other debris, by forming an antistatic resin layer. The antistatic agent contained in the resin composition for forming the resin layer is preferably a polymer type antistatic agent because it has good heat resistance and heat and humidity resistance. Examples of the polymer-type antistatic agents include compounds having ammonium groups, polyether compounds, compounds having sulfonic acid groups, betaine compounds, conductive polymers, and the like.

[0075] The aforementioned compounds having an ammonium group are compounds that have an ammonium group in their molecule, and examples include aliphatic amines, alicyclic amines, and ammonium compounds of aromatic amines. Compounds having an ammonium group are preferably polymeric compounds having an ammonium group, and it is preferable that the ammonium group is incorporated into the main chain or side chains of the polymer rather than as a counterion. For example, polymers having an ammonium group are obtained by polymerizing monomers containing an addition polymerizable ammonium group or an ammonium group precursor such as an amine, and these are suitably used. The polymer may be a monomer containing an addition polymerizable ammonium group or an ammonium group precursor such as an amine, polymerized alone, or it may be a copolymer of a monomer containing these and another monomer.

[0076] Among compounds containing an ammonium group, compounds containing a pyrrolidinium ring are also preferred due to their excellent antistatic properties and heat stability.

[0077] The two substituents bonded to the nitrogen atom of a compound having a pyrrolidinium ring are, independently, an alkyl group, a phenyl group, etc., and these alkyl groups and phenyl groups may be substituted with the groups shown below. Substitutable groups include, for example, hydroxyl groups, amide groups, ester groups, alkoxy groups, phenoxy groups, naphthoxy groups, thioalkoxy groups, thiophenoxy groups, cycloalkyl groups, trialkylammonium alkyl groups, cyano groups, and halogens.

[0078] Furthermore, the two substituents bonded to the nitrogen atom may be chemically bonded, for example, -(CH2)m- (m = integer from 2 to 5), -CH(CH3)CH(CH3)-, -CH=CH-CH=CH-, -CH=CH-CH=N-, -CH=CH-N=CH-, -CH2OCH2-, -(CH2)2O(CH2)2-, etc.

[0079] A polymer having a pyrrolidinium ring can be obtained by subjecting a diallylamine derivative to cyclopolymerization using a radical polymerization catalyst. The polymerization can be carried out by a known method using hydrogen peroxide, benzoyl peroxide, a tertiary butyl peroxide or the like as a polymerization initiator in water or a polar solvent such as methanol, ethanol, isopropanol, formamide, dimethylformamide, dioxane or acetonitrile as a solvent, but is not limited thereto. In the present invention, a compound having a carbon-carbon unsaturated bond polymerizable with the diallylamine derivative may be used as a copolymer component.

[0080] Also, from the viewpoint of excellent antistatic properties and moisture and heat resistance stability, it is also preferable that it is a polymer having a structure of the following general formula (3). It may be a single polymer or copolymer, or may further copolymerize a plurality of other components.

[0081]

Chemical formula

[0082] For example, in the above formula, the substituent R 1 is a hydrogen atom or a hydrocarbon group such as an alkyl group having 1 to 20 carbon atoms or a phenyl group, and R 2 is -O-, -NH- or S-, and R 3 is an alkylene group having 1 to 20 carbon atoms or another structure that can form the structure of the general formula (3), and R 4 , R 5 , R 6 are each independently a hydrogen atom, a hydrocarbon group such as an alkyl group having 1 to 20 carbon atoms or a phenyl group, or a hydrocarbon group to which a functional group such as a hydroxyalkyl group is added, and X - is various counter ions.

[0083] Among the above, particularly from the viewpoint of excellent antistatic properties and moisture and heat resistance stability, in the general formula (3), the substituent R 1 is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R 3 is preferably an alkyl group having 1 to 6 carbon atoms, and R 4 , R5 , R 6 Each is preferably independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and furthermore, R 4 , R 5 , R 6 Preferably, one of the substituents is a hydrogen atom, and the other substituents are alkyl groups having 1 to 4 carbon atoms.

[0084] Examples of anions that act as counterions to the ammonium group in the compounds having the ammonium group mentioned above include halogen ions, sulfonates, phosphates, nitrates, alkyl sulfonates, and carboxylates.

[0085] Furthermore, the number-average molecular weight of the compound having an ammonium group is 1,000 to 500,000, preferably 2,000 to 350,000, and more preferably 5,000 to 200,000. When the molecular weight is 1,000 or more, the strength of the coating film is sufficient and heat resistance stability is maintained. When the molecular weight is 500,000 or less, the viscosity of the coating liquid is reduced, resulting in good handling and application properties.

[0086] Examples of polyether compounds include polyethylene oxide, polyether ester amide, and acrylic resins having polyethylene glycol as a side chain.

[0087] A compound having a sulfonic acid group is a compound that contains sulfonic acid or a sulfonate salt within its molecule. For example, compounds containing a large amount of sulfonic acid or a sulfonate salt, such as polystyrene sulfonic acid, are preferably used.

[0088] Examples of the conductive polymers include polythiophene-based, polyaniline-based, polypyrrole-based, and polyacetylene-based polymers. Among these, polythiophene-based polymers, such as poly(3,4-ethylenedioxythiophene) used in combination with polystyrene sulfonic acid, are preferred. Conductive polymers are preferable to the other antistatic agents mentioned above in that they result in lower resistance values.

[0089] Furthermore, the resin layer may also contain, as needed, defoaming agents, coating improvers, thickeners, organic lubricants, UV absorbers, antioxidants, foaming agents, dyes, pigments, surfactants, and the like. The surfactant is not particularly limited, but a nonionic surfactant is preferred.

[0090] (Method for forming a resin layer) Methods for forming the aforementioned resin layer include, for example, coating, transfer, and lamination. Considering the ease of forming the resin layer, it is preferable to form it by coating. In the case of coating, it is preferable to dilute the resin composition for forming the resin layer with a solvent to make a coating solution, and it is preferable that the solvent is mainly water (50% by mass or more).

[0091] The coating method may be provided by in-line coating, which is performed within the film manufacturing process, or by offline coating, which is applied to a film that has already been manufactured outside of the system.

[0092] In-line coating is a method of coating a film at any stage from the melt-extrusion of the resin forming the film to stretching, heat-setting, and winding. The coating can be performed by applying a resin composition for forming a resin layer or a diluted solution of the resin composition for forming a resin layer to at least one side of the base film and drying and curing it as necessary. Typically, the coating is applied to an unstretched sheet obtained by melting and rapid cooling, a stretched uniaxially oriented film, a biaxially oriented film before heat fixing, or a film after heat fixing but before winding. While not limited to the above, for example, in sequential biaxial stretching, a method in which the uniaxially oriented film stretched in the longitudinal direction (vertical direction) is coated and then stretched in the transverse direction is particularly advantageous. This method offers cost advantages in manufacturing because film formation and resin layer formation can be performed simultaneously. Furthermore, since stretching is performed after coating, the thickness of the resin layer can be varied by the stretching ratio, making thin-film coating easier compared to offline coating. Therefore, in this film, it is particularly preferable to form the resin layer by in-line coating, as this facilitates the formation of a surface state that satisfies the above relational equations (1) and / or (2).

[0093] Furthermore, by providing a resin layer on the film before stretching, the resin layer can be stretched together with the base film, thereby allowing the resin layer to adhere firmly to the base film. Furthermore, in the manufacturing of biaxially oriented polyester film, the film can be restrained in both the longitudinal and transverse directions by gripping the film edges with clips or the like while stretching it. This allows for high temperatures to be applied during the heat setting process without wrinkles or other defects, while maintaining flatness.

[0094] Therefore, because the heat treatment applied after coating can reach temperatures unattainable by other methods, the film-forming properties of the resin layer are improved, allowing for stronger adhesion between the resin layer and the substrate film, resulting in an even stronger resin layer. This is particularly effective in reacting with crosslinking agents to achieve stable water-repellent performance.

[0095] Conventional coating methods such as gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze coating, impregnation coating, kiss coating, spray coating, calender coating, and extrusion coating can be used.

[0096] The drying and curing conditions for forming a resin layer on a substrate film are not particularly limited, but in the case of a coating method, the drying temperature of the solvent, such as water, used in the coating liquid is preferably in the range of 70 to 150°C, more preferably 80 to 130°C, and even more preferably 90 to 120°C. The drying time is approximately in the range of 3 to 200 seconds, preferably 5 to 120 seconds.

[0097] Furthermore, regardless of whether it is offline coating or in-line coating, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination as needed. The polyester film may be pre-treated with surface treatments such as corona treatment or plasma treatment.

[0098] <Application> This film is suitable for use as a protective film for adhesive sheets with a protective film / adhesive sheet configuration, which are used in the build-up method, one of the semiconductor manufacturing processes, specifically as a protective film for adhesive sheets used in the build-up layer of printed circuit boards.

[0099] <Adhesive sheet with protective film> The adhesive sheet with protective film of the present invention (hereinafter simply referred to as "this adhesive sheet") has a film / adhesive sheet configuration, and more specifically, it is composed of an adhesive sheet consisting of a support and a resin composition layer formed on the support, and this film (this film / resin composition layer / support).

[0100] (Resin composition layer) The resin composition for forming the resin composition layer preferably contains a thermosetting resin. Even when the adhesion between the film and the adhesive sheet is strengthened by the thermosetting resin, the film exhibits excellent peelability from the adhesive sheet. For example, when epoxy resin is used as the thermosetting resin, the resin composition layer becomes a relatively hard layer, but because the convex protrusions described above are formed on the film, the contact area with the resin composition layer is reduced, resulting in excellent peelability. Furthermore, the resin composition may optionally contain additives such as thermoplastic resins, curing accelerators, flame retardants, and rubber particles. The following describes epoxy resins, inorganic fillers, curing agents, and additives that can be used as specific embodiments of the resin composition.

[0101] (Epoxy resin) Examples of the epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol epoxy resin, naphthol novolac epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, spiroring-containing epoxy resin, cyclohexanedimethanol type epoxy resin, naphthylene ether type epoxy resin, and trimethylol type epoxy resin. The epoxy resin may be used alone or in combination of two or more types.

[0102] (Inorganic fillers) The aforementioned resin composition layer preferably contains an inorganic filler in order to keep thermal expansion low. The content of inorganic fillers in the resin composition layer is preferably 60% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more, when the total amount of non-volatile components in the resin composition layer is taken as 100% by mass, in order to reduce the coefficient of thermal expansion. Furthermore, from the viewpoint of mechanical strength, the upper limit of the inorganic filler content in the resin composition layer is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, when the total amount of non-volatile components in the resin composition layer is taken as 100% by mass.

[0103] Examples of the inorganic fillers include silica, alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium dioxide, barium zirconate, and calcium zirconate. Furthermore, the inorganic filler may be used alone or in combination of two or more types.

[0104] (Hardening agent) The curing agent is not particularly limited as long as it has the function of curing epoxy resin, and examples include phenolic curing agents, active ester curing agents, benzoxazine curing agents, and cyanate ester curing agents. The curing agent may be used alone or in combination of two or more types.

[0105] Examples of phenolic curing agents include biphenyl-type curing agents, naphthalene-type curing agents, phenol novolac-type curing agents, naphthylene ether-type curing agents, and nitrogen-containing phenolic curing agents.

[0106] (Additives) The resin composition may optionally further contain additives such as thermoplastic resins, curing accelerators, flame retardants, and rubber particles.

[0107] Examples of the thermoplastic resins include phenoxy resin, polyvinyl acetal resin, polyimide resin, polyamideimide resin, polyethersulfone resin, and polysulfone resin. These thermoplastic resins may be used individually or in combination of two or more types.

[0108] (Support) A film made of a plastic material is preferably used as the support. Examples of plastic materials include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polycarbonates, acrylics such as polymethyl methacrylate, cyclic polyolefins, triacetylcellulose, polyether sulfide, polyether ketone, and polyimide. Among these, polyethylene terephthalate film is preferred.

[0109] The laminated polyester film of the present invention exhibits excellent slipperiness and peelability due to the convex protrusions on the film surface. Furthermore, the laminated polyester film of the present invention reduces the contact area with the resin composition layer due to the convex protrusions on the film surface, thus exhibiting excellent peelability even when the adhesion to the adherend, for example, the adhesion to the resin composition layer, is strengthened by the formulation, type, modification, etc., of the resin composition. Furthermore, because the adhesive sheet with protective film of the present invention has convex protrusions in the resin layer, it can be wound into a roll without causing blocking, and a roll-shaped adhesive sheet with protective film also falls under the scope of the present invention. In this way, because it can be wound into a roll, it can be produced roll-to-roll, which is advantageous in terms of productivity. [Examples]

[0110] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples and comparative examples. Furthermore, the measurement and evaluation methods used in this invention are as follows.

[0111] (1) Method for measuring the intrinsic viscosity of polyester 1 g of polyester was accurately weighed, dissolved in 100 ml of a phenol / tetrachloroethane mixed solvent (50 / 50 by mass ratio), and measured at 30°C.

[0112] (2) Method for measuring the average particle size The average particle size was measured using a laser diffraction particle size distribution analyzer (SALD-2000J model, manufactured by Shimadzu Corporation).

[0113] (3) Method for measuring number-average molecular weight The number-average molecular weight was measured using a high-speed GPC instrument (HLC-8120GPC, manufactured by Tosoh Corporation). The number-average molecular weight was calculated on a polystyrene basis.

[0114] (4) Method for measuring the thickness of the base film The thickness of the base film was measured using a micrometer (DIGIMATIC ICROMETER CLM1-15QM, manufactured by Mitutoyo).

[0115] (5) Method for measuring the height of surface convex protrusions The height of the surface convex protrusions was determined by cutting a cross-section of the test specimen and using an electron microscope (Hitachi High-Technologies Corporation, "S-3400N") to photograph the cross-section under an acceleration voltage of 5kV. The amount of protrusion from the film surface was measured from the captured image and defined as the surface convex protrusion height. Measurements were performed on five protrusions, and the average value was taken as the surface convex protrusion height.

[0116] (6) Method for measuring 180° peeling force The adhesive side of a 5cm wide adhesive tape (Nitto Denko Corporation's "No. 31B") was pressed onto the resin layer side of a laminated polyester film by applying pressure with a rubber roller with a load of 2kg, passing it back and forth once. The peeling force was then measured after being left at 23°C for 1 hour. The peeling force was measured using a small benchtop testing machine ("AGX-plus" manufactured by Shimadzu Corporation) under conditions of an ambient temperature of 23°C and a tensile speed of 300 mm / min, by performing a 180° peel.

[0117] The methods for producing the polyester used in the examples and comparative examples are as follows:

[0118] <Method for manufacturing polyester (A)> Using 100 parts by mass of dimethyl terephthalate and 55 parts by mass of ethylene glycol as starting materials, 0.04 parts by mass of magnesium acetate tetrahydrate was added to the reactor as a catalyst. The reaction was started at 150°C, and the reaction temperature was gradually increased with the distillation of methanol until it reached 230°C after 3 hours. After 4 hours, the transesterification reaction was substantially completed. To this reaction mixture, 0.02 parts by mass of ethyl acid phosphate was added, followed by 0.04 parts by mass of antimony trioxide, and a polycondensation reaction was carried out for 4 hours. The reaction temperature was gradually increased from 230°C to 280°C. Meanwhile, the pressure was gradually reduced from atmospheric pressure until it reached 0.3 mmHg. After the reaction started, the reaction was stopped by changing the stirring power of the reaction vessel when the intrinsic viscosity reached 0.65, and the polymer was discharged under nitrogen pressure to obtain polyester (A) with an intrinsic viscosity of 0.65.

[0119] <Method for manufacturing polyester (B)> To the above-mentioned polyester (A), which is substantially particle-free, 15% by mass of silica particles with an average primary particle diameter of 4.1 μm was added, and the mixture was kneaded using a vented twin-screw kneader to obtain polyester (B).

[0120] <Method for manufacturing polyester (C)> To the above-mentioned polyester (A), which is substantially particle-free, 0.2% by mass of silica particles with an average primary particle diameter of 3.2 μm was added, and the mixture was kneaded using a vented twin-screw kneader to obtain polyester (C).

[0121] <Preparation of coating solution> Coating solutions 1 and 2 were prepared by diluting the resin layer-forming resin composition obtained by stirring and mixing the materials according to the composition shown in Table 1 below with water. The values ​​in the table represent parts by mass. The materials used in the composition are as follows.

[0122] <Release agent; Long-chain alkyl-containing compound (I)> A long-chain alkyl group-containing compound obtained by adding octadecyl isocyanate to polyvinyl alcohol with an average degree of polymerization of 500 and a degree of saponification of 88 mol%.

[0123] <Crosslinking agent; Melamine compound (II)> Hexamethoxymethylolmelamine

[0124] <Surfactants; Nonionic surfactants (III)> Nonionic surfactants with a structure containing polyethylene oxide in the side chains.

[0125] [Table 1]

[0126] [Example 1] Mixed raw materials, consisting of the aforementioned polyesters (A) and (B) in proportions of 89% and 11% by mass respectively, were supplied to a vented twin-screw extruder. Both were melted at 288°C and co-extruded. The extruded material was then cooled and solidified on a cooling roll with a surface temperature of 34°C using an electrostatic contact method to obtain an unstretched sheet. Next, the film was stretched 3.8 times in the longitudinal direction at a film temperature of 83°C using the difference in roll peripheral speed. Coating solution 1 was applied to both sides of this longitudinally stretched film, guided into a tenter, and stretched 3.6 times in the transverse direction at 118°C. After heat treatment at a main crystallization zone temperature of 235°C, the film was relaxed by 2% in the transverse direction to obtain a biaxially oriented polyester film (laminated polyester film 1) with a thickness of 10 μm.

[0127] [Example 2] A laminated polyester film 2 was obtained in the same manner as in Example 1, except that coating solution 1 was changed to coating solution 2.

[0128] [Comparative Example 1] A laminated polyester film 3 was obtained in the same manner as in Example 1, except that no coating solution was applied (i.e., no resin layer was present). The film thickness was 9 μm.

[0129] [Comparative Example 2] The polyester film composition and stretching ratio were changed as shown in Table 2, and the film was manufactured in the same manner as in Example 1, except for the changes, to obtain laminated polyester film 4. The film thickness was 50 μm.

[0130] [Comparative Example 3] The polyester film composition and stretching ratio were changed as shown in Table 2, and the film was manufactured in the same manner as in Example 2, except for the changes, to obtain laminated polyester film 5. The film thickness was 50 μm.

[0131] The properties of the laminated polyester films 1 to 5 prepared in the examples and comparative examples are shown in Table 2 below.

[0132] [Table 2]

[0133] The laminated polyester films 1 and 2 of the example not only exhibit a release effect due to the resin layer, but also form a specific surface state, thus possessing excellent release properties even when the adhesive strength is improved, regardless of the adhesive material of the adhesive sheet. On the other hand, the laminated polyester film 3 of Comparative Example 1 lacks a resin layer, making it difficult to peel off. Since it does not form a specific surface condition, it is suggested that if the adhesive strength with the adhesive material of the adhesive sheet is improved, it will be difficult to satisfy the peelability requirements. Furthermore, although the laminated polyester films 4 and 5 of Comparative Examples 2 and 3 exhibit a peeling effect, they do not form a specific surface state. This suggests that if the adhesion strength between the adhesive sheet and the adhesive material is improved, it will be difficult to satisfy the peeling requirement. [Industrial applicability]

[0134] The laminated polyester film of the present invention has excellent slipperiness and peelability due to the convex protrusions on the film surface, and can therefore be suitably used, for example, as a protective film for adhesive sheets with a protective film used in the build-up method, one of the semiconductor manufacturing processes.

Claims

1. The base film has a resin layer on at least one surface, The aforementioned base film is a resin film containing polyester, has a thickness of less than 15 μm, and contains particles. The resin layer has convex protrusions derived from the particles, When the thickness of the base film is A (μm) and the height of the convex protrusion is B (μm), the following relational expression (1) is satisfied, A laminated polyester film that satisfies the following relation (2), where C (μm) is the average particle diameter of the aforementioned particles, and the 180° peel strength of the resin layer is 30 to 330 mN / cm. 0.10≦B / A<0.23...(1) (However, the height B of the convex protrusion refers to the height from the lowest part of the resin layer's surface to the apex of the convex protrusion.) 0.25<B / C≦0.50...(2)

2. The laminated polyester film according to claim 1, wherein the intrinsic viscosity of the resin film is 0.50 dl / g or more.

3. The laminated polyester film according to claim 1 or 2, wherein the average particle size of the particles is 1 to 10 μm.

4. The laminated polyester film according to any one of claims 1 to 3, wherein the resin layer comprises a non-silicone mold release agent.

5. The laminated polyester film according to claim 4, wherein the non-silicone release agent contains a long-chain alkyl group-containing compound.

6. The laminated polyester film according to any one of claims 1 to 5, wherein the resin layer is formed from a resin composition containing a crosslinking agent.

7. The laminated polyester film according to claim 6, wherein the crosslinking agent is a melamine-based compound.

8. It has an adhesive sheet and a protective film, The protective film is a laminated polyester film according to any one of claims 1 to 7, wherein the protective film is an adhesive sheet with a protective film.

9. The adhesive sheet with protective film according to claim 8, wherein the adhesive sheet comprises a support and a resin composition layer formed on at least one surface of the support.

10. Adhesive sheet with protective film according to claim 8 or 9, for use as a build-up layer for printed circuit boards.

11. A roll-shaped adhesive sheet with protective film, wherein the adhesive sheet with protective film according to any one of claims 8 to 10 is wound into a roll.

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