Laminated Film

Abstract

To provide a laminated film which enables provision of a resin sheet having both high smoothness and good slipperiness without substantially adding particles to the inside of the resin sheet.SOLUTION: A laminated film is provided, which is formed by laminating a resin sheet 12 and an easily sliding layer 13 in this order on at least one surface of a base material film 10, wherein the base material film is composed of a polyester film, and satisfies the following conditions. The resin sheet has a haze of 2% or less or the resin sheet has a dielectric breakdown voltage of 200 V / μm or more, film thickness (t1) of the resin sheet is 1 μm or mor and 20 μm or less, the easily sliding layer contains at least binder resin and particles 14, film thickness (t2) of the easily sliding layer is 0.001 μm or more and 1 μm or less, the film thickness (t2) of the easily sliding layer is 20% or less of the film thickness (t1) of the resin sheet, and peeling force necessary for peeling a resin sheet with an easily sliding layer from the base material film is 800 mN / 25 mm width or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminated film having a resin sheet laminated thereon, and more particularly to a laminated film having a resin sheet laminated thereon that is used for electronic components and optical applications. [Background technology]

[0002] Conventionally, release films based on polyester film have high heat resistance and mechanical properties and have been used as process films in solution casting of resin sheets such as pressure-sensitive adhesive sheets, cover films, polymer electrolyte membranes, and dielectric resin sheets. In recent years, high smoothness and transparency are required for resin sheets used in electronic components and optical applications, particularly dielectric resin sheets used in film capacitors, and therefore high smoothness has also been required for the surface of release films used as process films. For this reason, technologies such as those described in Patent Documents 1 to 3 have been disclosed, and release layer surfaces with low surface roughness have been proposed.

[0003] However, for example, while high smoothness is required for optical applications to improve transparency, too much smoothness can also result in poor slippage, which can lead to scratches during transportation and other processes, resulting in reduced yields. Also, for electronic component applications such as film capacitors, smoothness is required to improve electrical properties such as breakdown voltage, but too much smoothness can result in poor slippage, which can lead to misalignment and wrinkles when the dielectric resin sheet is wound onto a roll, making it difficult to wind properly and reducing the performance of the film capacitor.

[0004] To improve these problems, Patent Document 4 proposes adding specific particles to resin sheets used for optical purposes such as polarizing plates to impart slipperiness. Also, Patent Document 5 proposes a method of transferring particles on a substrate film to a resin sheet used for film capacitors and the like.

[0005] However, in the method of Patent Document 4, since particles are contained in the resin sheet, there is a concern that the transparency may be insufficient, such as an increase in internal haze, etc. Also, in the method of Patent Document 5, there is a risk that the amount of particles transferred to the resin sheet may be uneven, which may cause unstable slip properties. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-144021 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-154273 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-182261 [Patent Document 4] Japanese Patent Application Publication No. 2019-95661 [Patent Document 5] International Publication No. 2020 / 039638 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention is intended to solve the above problems, and proposes a laminated film that can provide a resin sheet that has both high smoothness and good slip properties without substantially adding particles to the interior of the resin sheet. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that a resin sheet that is both highly smooth and has good slip properties can be provided by forming a resin sheet that is substantially free of particles on a smooth substrate film and then providing a laminated film in which a lubrication layer having an optimal thickness is provided. Furthermore, according to the present invention, even in the case of a resin sheet formed using a highly smooth release film, the conventional problems can be solved, and a resin sheet having both high smoothness and good slip properties can be provided.

[0009] That is, the present invention comprises the following: [1] A laminated film obtained by laminating a resin sheet and a lubricating layer in this order on at least one surface of a base film, the base film being a polyester film, and satisfying the following (1) to (6): (1) The arithmetic mean height (Sa) of the surface of the base film on which the resin sheet is laminated is 20 nm or less, and the maximum protrusion height (P) is 200 nm or less. (2) The thickness (t1) of the resin sheet is 1 μm or more and 20 μm or less; (3) The slip layer contains at least a binder resin and particles. (4) The thickness (t2) of the slip layer is 0.001 μm or more and 1 μm or less. (5) The thickness (t2) of the slip layer is 20% or less of the thickness (t1) of the resin sheet. (6) The peeling force when peeling the resin sheet with the lubricating layer from the substrate film is 800 mN / 25 mm width or less. [2] The laminated film described above, further comprising a release layer provided between the base film and the resin sheet. [3] The laminated film as described above, wherein the binder component contained in the slip layer is the same as the main resin component contained in the resin sheet. [4] The laminated film, wherein the lubricity layer is substantially free of a crosslinking agent. [5] The substrate film has a surface layer A on the surface facing the resin sheet, The above laminate film, wherein the surface layer A is a layer that is substantially free of particles, and has an arithmetic mean height (Sa) of 20 nm or less and a maximum projection height (P) of 200 nm or less. [6] A method for producing the laminated film, characterized in that a resin sheet and a lubricating layer are coated in this order on a substrate film by a solution casting method. [Effects of the Invention]

[0010] By using the laminated film of the present invention, a resin sheet having both high smoothness and good slip properties can be provided, and by using the resin sheet formed by the present invention, good products can be provided for various applications. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of the laminated film of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically showing another example of the laminated film of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The laminate film of the present invention is a laminate film obtained by sequentially laminating a resin sheet and a lubricating layer on at least one surface of a base film. For example, FIGS. 1 and 2 are cross-sectional views schematically illustrating an example of the laminate film of the present invention. FIG. 1 shows an example of a laminate film configuration in which a base film 10 does not have a release layer, and the film has a resin sheet 12 and a lubricating layer 13. The lubricating layer 13 also has particles 14. FIG. 2 shows an embodiment in which a release layer 11 is provided between the base film 10 and the resin sheet 12. The size and shape of each component in the figure are merely examples.

[0013] (Base film) The polyester constituting the polyester film used as the substrate of the present invention is not particularly limited, and a film formed from a polyester commonly used as a substrate film can be used. A crystalline linear saturated polyester composed of an aromatic dibasic acid component and a diol component is preferred. For example, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polytrimethylene terephthalate, or a copolymer mainly composed of these resin components is more preferred. In particular, a polyester film formed from polyethylene terephthalate is particularly preferred. The polyethylene terephthalate preferably contains 90 mol % or more, more preferably 95 mol % or more, of ethylene terephthalate repeating units, and may contain small amounts of other dicarboxylic acid components or diol components copolymerized therein. From the viewpoint of cost, polyethylene terephthalate produced from terephthalic acid and ethylene glycol alone is preferred. Furthermore, known additives such as antioxidants, light stabilizers, ultraviolet absorbers, and crystallizing agents may be added within a range that does not impair the effects of the film of the present invention. The polyester film is preferably a biaxially oriented polyester film due to its high bidirectional elastic modulus.

[0014] The intrinsic viscosity of the polyethylene terephthalate film is preferably 0.50 to 0.70 dL / g, more preferably 0.52 to 0.62 dL / g. When the intrinsic viscosity is 0.50 dL / g or more, breakage does not occur frequently during the stretching process, which is preferable. Conversely, when the intrinsic viscosity is 0.70 dL / g or less, cuttability is good when cutting to a predetermined product width, and dimensional defects do not occur, which is preferable. In addition, it is preferable to thoroughly vacuum dry the raw material pellets.

[0015] The method for producing the polyester film of the present invention is not particularly limited, and any conventionally commonly used method can be used. For example, the polyester can be melted in an extruder, extruded into a film, and cooled on a rotating cooling drum to obtain an unstretched film, which can then be stretched. Biaxial stretching is preferred in terms of mechanical properties, etc. A biaxially stretched film can be obtained by sequentially biaxially stretching a uniaxially stretched film in the longitudinal or transverse direction in the transverse or longitudinal direction, or by simultaneously biaxially stretching an unstretched film in the longitudinal and transverse directions.

[0016] In the present invention, the stretching temperature during stretching of the polyester film is preferably equal to or higher than the second-order transition point (Tg) of the polyester, and the stretching is preferably 1 to 8 times, particularly 2 to 6 times, in both the longitudinal and transverse directions.

[0017] The polyester film preferably has a thickness of 6 μm or more and 50 μm or less, more preferably 9 μm or more and 31 μm or less, and even more preferably 12 μm or more and 28 μm or less. A film thickness of 6 μm or more is preferred because there is no risk of deformation due to heat during film production, during the processing step of the release layer, during molding of the resin sheet, etc. On the other hand, a film thickness of 50 μm or less is preferred because the diameter of the film when wound into a roll is small and the roll length of the resin sheet to be molded can be increased. When the polyester film used as the base film has a multilayer structure as described below, the thickness of the entire base film falls within the above range.

[0018] The polyester film may be a single layer or a multilayer film of two or more layers. It is preferable that at least one surface of the polyester film is provided with a surface layer A that is substantially free of particles. In one embodiment, the polyester film serving as the substrate film has the surface layer A on the surface facing the resin sheet. When the substrate film is a laminated polyester film having a multilayer structure of two or more layers, it is preferable that the surface layer B that can contain particles or the like is provided on the surface opposite the surface layer A that is substantially free of particles. As for the layer structure, when the layer on the side where the resin sheet is placed is the surface layer A, the layer on the opposite side is the surface layer B, and the other core layer is the layer C, the layer structure in the thickness direction may be a layer structure such as A / B or A / C / B. Layer C may be composed of multiple layers. Surface layer B may not contain particles. In this case, it is preferable to provide a coating layer containing particles and a binder on surface layer B to impart slip properties for winding the film into a roll.

[0019] A release layer may be provided on the surface layer A of the polyester film to improve the releasability of the resin sheet. It is particularly preferable to provide a release layer when the resin sheet contains a crosslinking agent. When a release layer is laminated, it is also preferable that the release layer does not substantially contain particles.

[0020] In the polyester film of the present invention, the surface layer A located on the surface where the resin sheet is formed preferably contains substantially no particles. Furthermore, the arithmetic mean height (Sa) of the surface layer A of the polyester film is preferably 20 nm or less. Furthermore, the arithmetic mean height (Sa) is particularly preferably 10 nm or less. When Sa is 20 nm or less, pinholes and local thickness variations are less likely to occur during the molding of the resin sheet, which is preferable. The smaller the arithmetic mean height (Sa) of the surface layer A, the more preferable it is, but it may be 0.1 nm or more. Here, when a release layer, etc., described below, is provided on the surface layer A, it is preferable that the release layer contains substantially no particles, and it is preferable that the arithmetic mean height (Sa) after lamination of the release layer falls within the above range. In the present invention, "substantially no particles" means, for example, in the case of inorganic particles, that the content of inorganic elements is 50 ppm or less, preferably 10 ppm or less, and most preferably below the detection limit, when quantified by fluorescent X-ray analysis. This is because even if particles are not actively added to the film, contaminants from foreign matter or dirt adhering to the raw resin or the lines and equipment used in the film manufacturing process may peel off and become mixed into the film.

[0021] The surface layer A of the polyester film preferably has a maximum protrusion height (P) of 200 nm or less, more preferably 150 nm or less, even more preferably 100 nm or less, for example, 85 nm or less, particularly preferably 50 nm or less. If the maximum protrusion height (P) is 200 nm or less, defects such as pinholes and localized thinning do not occur during resin sheet formation, and the yield is favorable, which is preferable. It can be said that the smaller P of the surface layer A of the polyester film is the better, but it may be 1 nm or more, or 3 nm or more. Here, when a release layer or the like described below is provided on the surface layer A, it is preferable that the maximum protrusion height (P) after lamination of the release layer falls within the above range.

[0022] In the polyester film of the present invention, surface layer B, which forms the surface opposite surface layer A, preferably contains particles from the viewpoint of the film's slipperiness and ease of air escape, and silica particles and / or calcium carbonate particles are particularly preferred. The particle content is preferably 5,000 to 15,000 ppm in total in surface layer B. In this case, the arithmetic mean height (Sa) of the film in surface layer B is preferably in the range of 1 to 40 nm, more preferably 5 to 35 nm. When the total content of silica particles and / or calcium carbonate particles is 5,000 ppm or more and Sa is 1 nm or more, air can be uniformly released when the film is wound into a roll, resulting in a good wound shape and good flatness, making it suitable for the production of resin sheets. Furthermore, when the total content of silica particles and / or calcium carbonate particles is 15,000 ppm or less and Sa is 40 nm or less, the lubricant is less likely to aggregate and large protrusions are not formed, resulting in stable quality during resin sheet molding, which is preferred.

[0023] In addition to silica and / or calcium carbonate, the particles contained in the surface layer B may also include inert inorganic particles and / or heat-resistant organic particles. From the standpoint of transparency and cost, it is more preferable to use silica particles and / or calcium carbonate particles. Other inorganic particles that can be used include alumina-silica composite oxide particles and hydroxyapatite particles. Examples of heat-resistant organic particles include cross-linked polyacrylic particles, cross-linked polystyrene particles, and benzoguanamine particles. When silica particles are used, porous colloidal silica is preferred. When calcium carbonate particles are used, light calcium carbonate that has been surface-treated with a polyacrylic acid-based polymer compound is preferred from the standpoint of preventing the lubricant from falling off.

[0024] The average particle size of the particles added to the surface layer B is preferably 0.1 μm or more and 2.0 μm or less, and particularly preferably 0.5 μm or more and 1.0 μm or less. An average particle size of 0.1 μm or more is preferable because the slipperiness of the substrate film is good. Furthermore, an average particle size of 2.0 μm or less is preferable because there is no risk of pinholes being generated in the resin sheet due to coarse particles in the surface layer B.

[0025] The surface layer B may contain two or more types of particles made of different materials, or may contain particles of the same type but with different average particle sizes.

[0026] When surface layer B does not contain particles, it is preferable to provide easy slippage by a coating layer containing particles on surface layer B. This coating layer is not particularly limited, but is preferably provided by in-line coating, in which coating is performed during the production of the polyester film. When surface layer B does not contain particles but has a coating layer containing particles on surface layer B, the surface of the coating layer preferably has an arithmetic mean height (Sa) in the range of 1 to 40 nm, for the same reasons as for the arithmetic mean height (Sa) of surface layer B described above. It is more preferably in the range of 5 to 35 nm.

[0027] From the viewpoint of reducing pinholes, it is preferable that recycled raw materials or the like are not used for the surface layer A, which is the layer on which the resin sheet is to be provided, in order to prevent particles such as lubricants from being mixed in.

[0028] The thickness ratio of the surface layer A, which is the layer on which the resin sheet is provided, is preferably 20% to 50% of the total thickness of the base film. If it is 20% or more, the film is less likely to be affected from the inside by particles contained in the surface layer B, etc., and it is easy to ensure that the arithmetic mean height (Sa) satisfies the above range, which is preferable. If it is 50% or less of the total thickness of the base film, the proportion of recycled materials used in the surface layer B can be increased, which is preferable because it reduces the environmental impact.

[0029] From an economical standpoint, recycled raw materials such as film scraps and PET bottles can be used in an amount of 50 to 90% by mass for the layers (surface layer B or the aforementioned intermediate layer C) other than the surface layer A. Even in this case, it is preferable that the type and amount of the lubricant contained in the surface layer B, as well as the particle size and arithmetic mean height (Sa) thereof, satisfy the above ranges.

[0030] Furthermore, in order to improve the adhesion of a release layer or the like to be applied later, to prevent static electricity, or the like, a coating layer may be provided on the surface of surface layer A and / or surface layer B before stretching or after uniaxial stretching in the film-forming process, and corona treatment or the like may also be performed. When a coating layer is provided on surface layer A, it is preferable that the coating layer does not substantially contain particles.

[0031] (Release layer) In one embodiment of the present invention, a release layer is further provided between the substrate film and the resin sheet. For example, the substrate film of the present invention may have a release layer laminated on the surface layer A. The resin constituting the release layer is not particularly limited, and silicone resins, fluororesins, alkyd resins, various waxes, aliphatic olefins, etc. can be used, and each resin can be used alone or in combination of two or more types. When a crosslinking agent is contained in the resin sheet described below, it is preferable to contain a silicone resin because this improves releasability.

[0032] The release layer can contain, for example, a silicone resin. Silicone resins are resins having a silicone structure within the molecule, and examples include curable silicones, silicone graft resins, and modified silicone resins such as alkyl-modified silicones. However, from the viewpoint of migration, it is preferable to use a reactive curable silicone resin. Examples of reactive curable silicone resins that can be used include addition reaction-based resins, condensation reaction-based resins, and ultraviolet or electron beam curable resins. More preferably, low-temperature curable addition reaction-based resins that can be processed at low temperatures, and ultraviolet or electron beam curable resins are preferred. By using these resins, processing can be performed at low temperatures when coating polyester films. Therefore, heat damage to the polyester film during processing is reduced, a polyester film with high flatness can be obtained, and defects such as pinholes can be reduced even when producing thin resin sheets.

[0033] Examples of silicone resins that use addition reactions include those that are cured by reacting polydimethylsiloxane, which has vinyl groups at the terminals or side chains, with hydrogen siloxane using a platinum catalyst. In this case, it is more preferable to use a resin that can be cured within 30 seconds at 120°C, as this allows for processing at low temperatures. Examples include low-temperature addition-cure types (LTC1006L, LTC1056L, LTC300B, LTC303E, LTC310, LTC314, LTC350G, LTC450A, LTC371G, LTC750A, LTC755, LTC760A, etc.) and thermal UV-cure types (LTC851, BY24-510, BY24-561, BY24-562, etc.) manufactured by Dow-Toray; and solvent addition + UV-cure types (X62-5040, X62-5065, X62-5072T, KS5508, etc.) and dual-cure types (X62-2835, X62-2834, X62-1980, etc.) manufactured by Shin-Etsu Chemical.

[0034] An example of a condensation reaction silicone resin is one in which a polydimethylsiloxane having an OH group at its terminal and a polydimethylsiloxane having an H group at its terminal are subjected to a condensation reaction using an organotin catalyst to form a three-dimensional crosslinked structure.

[0035] Examples of UV-curable silicone resins include, for example, the most basic type that utilizes the same radical reaction as normal silicone rubber crosslinking, those that introduce unsaturated groups to cause photocuring, those that use UV light to decompose onium salts to generate strong acids that then cleave epoxy groups to cause crosslinking, and those that crosslink via an addition reaction of thiol to vinyl siloxane. Also, electron beams can be used instead of UV light. Electron beams have stronger energy than UV light, making it possible to carry out a radical-based crosslinking reaction without using an initiator as in UV curing. Examples of resins that can be used include UV-curable silicones manufactured by Shin-Etsu Chemical Co., Ltd. (X62-7028A / B, X62-7052, X62-7205, X62-7622, ​​X62-7629, X62-7660, etc.), UV-curable silicones manufactured by Momentive Performance Materials (TPR6502, TPR6501, TPR6500, UV9300, UV9315, XS56-A2982, UV9430, etc.), and UV-curable silicones manufactured by Arakawa Chemical Industries, Ltd. (Silicolyse UV POLY200, POLY215, POLY201, KF-UV265AM, etc.).

[0036] The UV-curable silicone resin may be an acrylate-modified or glycidoxy-modified polydimethylsiloxane, etc. Good release properties can also be achieved by mixing such modified polydimethylsiloxane with a polyfunctional acrylate resin or epoxy resin, etc., and using the mixture in the presence of an initiator.

[0037] Other suitable examples of resins that can be used include stearyl-modified or lauryl-modified alkyd resins or acrylic resins, or alkyd-based resins, acrylic-based resins, and olefin-based resins obtained by reaction of methylated melamine.

[0038] Examples of the amino alkyd resin obtained by a reaction such as with methylated melamine include Tesfine 303, Tesfine 305, and Tesfine 314 manufactured by Hitachi Chemical Co., Ltd. Examples of the amino acrylic resin obtained by a reaction such as with methylated melamine include Tesfine 322 manufactured by Hitachi Chemical Co., Ltd.

[0039] When the above resins are used in the release layer of the present invention, they may be used alone or in combination of two or more. In addition, additives such as light release additives and heavy release additives may be added to adjust the release force.

[0040] The release layer of the present invention may contain additives such as an adhesion improver and an antistatic agent. In order to improve adhesion to the substrate, it is also preferable to subject the surface of the polyester film to pretreatment such as anchor coating, corona treatment, plasma treatment, or atmospheric pressure plasma treatment before providing the release layer.

[0041] In the present invention, the thickness of the release layer may be set depending on the intended use and is not particularly limited, but is preferably in the range of 0.005 to 2.0 μm after curing. A release layer thickness of 0.005 μm or more is preferable because release performance is maintained. Furthermore, a release layer thickness of 2.0 μm or less is preferable because the curing time is not too long and there is no risk of uneven thickness of the resin sheet due to a decrease in the flatness of the release film. Furthermore, because the curing time is not too long, there is no risk of the resin constituting the release coating layer agglomerating and forming protrusions, which is preferable because pinhole defects in the resin sheet are less likely to occur.

[0042] The surface free energy of the release layer provided on the substrate film of the present invention is 15 mJ / m 2 More preferably, it is 18 mJ / m or more. 2 or more, and 20 mJ / m 2 More preferably, 15 mJ / m 2 If the thickness is more than this, repelling or the like is less likely to occur when the solution for the resin sheet is applied, which is preferable.

[0043] The surface free energy of the release layer provided on the base film of the present invention is 45 mJ / m 2 It is preferably 40 mJ / m or less. More preferably, it is 40 mJ / m 2 less than 35mJ / m 2 More preferably, it is 45 mJ / m 2 If it is less than this, the molded resin sheet will have good releasability, which is preferable. In the present invention, the surface free energy means the surface free energy of at least the surface of the release layer that comes into contact with the resin sheet.

[0044] In the present invention, the method for forming the release layer is not particularly limited, and a method is used in which a coating liquid in which a release resin is dissolved or dispersed is spread by coating or the like on one side of a polyester film substrate, the solvent is removed by drying, and then the resulting layer is heated, heat-cured, or UV-cured. In this case, the drying temperature during solvent drying and heat-curing is preferably 180°C or less, more preferably 150°C or less, and most preferably 120°C or less. The heating time is preferably 30 seconds or less, more preferably 20 seconds or less. A temperature of 180°C or less maintains the flatness of the film and reduces the risk of thickness unevenness in the resin sheet, which is preferable. A temperature of 120°C or less is particularly preferable because it allows processing without impairing the flatness of the film and further reduces the risk of thickness unevenness in the resin sheet. Furthermore, in an embodiment in which the substrate film according to the present invention has the surface layer A on the surface facing the resin sheet, the release layer can improve the releasability of the resin sheet. For example, even if the resin sheet contains a crosslinking agent, good releasability can be exhibited.

[0045] Any known coating method can be used as the coating method for the release layer, and conventionally known methods such as roll coating methods such as gravure coating and reverse coating, bar coating methods such as wire bars, die coating, spray coating, and air knife coating can be used.

[0046] (resin sheet) The resin sheet to be laminated on the substrate film of the present invention is one in which 30% by mass or more of the components constituting the resin sheet are organic components, which are not particularly limited and may include epoxy resins, phenoxy resins, polyester resins, urethane resins, fluorine resins, acrylic resins, olefin resins, imide resins, sulfone resins, etc.

[0047] The resin sheet may have a crosslinked structure containing a crosslinking agent such as isocyanate, melamine, carbodiimide, or oxazoline. Furthermore, as long as the above range is satisfied, additives other than the organic component may be included. However, it is preferable that the resin sheet is substantially free of particles. This is preferable because it is likely to provide benefits such as increased transparency of the molded resin sheet for optical applications and improved electrical properties for electronic components such as dielectric sheets used in film capacitors.

[0048] The resin sheet of the present invention is preferably produced by forming a coating liquid obtained by dissolving or dispersing the organic component in an organic solvent, water, or the like on a substrate film by a solution casting method, and the coating can be carried out by a known method, similar to the method for coating the release layer. For example, conventionally known methods such as roll coating methods such as gravure coating and reverse coating, bar coating methods such as wire bar coating, die coating, spray coating, and air knife coating can be used.

[0049] The thickness (t1) of the resin sheet of the present invention is 1 μm or more and 20 μm or less. More preferably, it is 1 μm or more and 10 μm or less, and even more preferably, it is 2 μm or more and 8 μm or less. If the thickness (t1) of the resin sheet is 1 μm or more, it is preferable because it is less likely to break after peeling from the base film and can be easily handled. If the thickness (t1) of the resin sheet is 20 μm or less, it is preferable because the wet coating film thickness does not become too thick during solution casting and molding is easy.

[0050] The film thickness (t1) of the resin sheet is not particularly limited and can be measured by known methods, but can also be measured by using a contact film thickness meter, an optical interference film thickness meter, or by observing the cross section using a scanning electron microscope or a transmission electron microscope.

[0051] In one embodiment, the resin sheet is substantially free of particles. "Substantially free of particles" has the same meaning as above. Since the present invention is a laminate film having a specific structure, the resin sheet can be substantially free of particles. Furthermore, since the resin sheet is substantially free of particles, it has high transparency for optical applications and can exhibit excellent electrical properties for electronic components such as film capacitors. For example, for optical applications, the resin sheet can have a haze of 2% or less. The haze may be 1% or less. In one embodiment, the haze of the resin sheet is 0.1% or more. When the haze is in this range, the resin sheet of the present invention can exhibit high transparency. Furthermore, for electronic components such as film capacitors, the resin sheet may have a breakdown voltage of 200 V / μm or more. The breakdown voltage may also be 300 V / μm or more. In one embodiment, the breakdown voltage is 400 V / μm or less. When the resin sheet has such a value, for example, an electronic component such as a film capacitor can exhibit excellent electrical properties.

[0052] (Easy layer) The present invention comprises a resin sheet and a lubrication layer laminated in this order on at least one side of a substrate film. The lubrication layer preferably contains at least a binder resin and particles. Various additives such as crosslinkers, surfactants, and catalysts may also be added.

[0053] The binder resin is not particularly limited, and may include epoxy resins, phenoxy resins, polyester resins, urethane resins, fluorine resins, acrylic resins, olefin resins, imide resins, sulfone resins, etc., but it is preferable to use the resin contained as the main component in the resin sheet. It is preferable for the binder resin of the lubrication layer to contain the same resin as the main component of the resin sheet, as this eliminates the difference in refractive index and dielectric constant between the resin sheet and the lubrication layer, resulting in optical and electrical advantages. In the present invention, the main component is defined as being contained in an amount of 50% by mass or more of all the components constituting the layer.

[0054] The particles contained in the lubrication layer may be inorganic particles or organic particles, and are not particularly limited. Examples of suitable inorganic particles include: (1) inorganic particles such as silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, zirconium oxide, titanium dioxide, satin white, aluminum silicate, diatomaceous earth, calcium silicate, aluminum hydroxide, hydrated halloysite, calcium carbonate, magnesium carbonate, calcium phosphate, magnesium hydroxide, and barium sulfate; and (2) organic particles such as acrylic or methacrylic, vinyl chloride, vinyl acetate, nylon, styrene / acrylic, styrene / butadiene, polystyrene / acrylic, polystyrene / isoprene, polystyrene / isoprene, methyl methacrylate / butyl methacrylate, melamine, polycarbonate, urea, epoxy, urethane, phenol, diallyl phthalate, and polyester. Silica is particularly preferred because it provides the coating layer with adequate slip properties.

[0055] The average particle size of the particles is, for example, 5 nm or more, preferably 10 nm or more, more preferably 11.5 nm or more, and even more preferably 30 nm or more. When the average particle size of the particles is 5 nm or more, the particles are less likely to aggregate and lubricity can be ensured, which is preferable.

[0056] The average particle size of the particles is, for example, 3 μm or less, preferably 600 nm or less, more preferably 400 nm or less, and even more preferably 200 nm or less. When the average particle size of the particles is 3 μm or less, transparency is maintained and the particles do not fall off, which is preferable.

[0057] In addition, for example, it is also preferable to mix small particles having an average particle size of about 5 to 100 nm with large particles having an average particle size of about 100 to 600 nm in order to exhibit good slip properties. When mixing small particles and large particles, it is preferable to make the mass content of the small particles larger than the mass content of the large particles relative to the total solid content of the lubrication layer.

[0058] The average particle size of the particles can be measured by observing the particles on the cross section of the processed film using a transmission electron microscope or a scanning electron microscope, observing 100 non-agglomerated particles, and taking the average value as the average particle size.

[0059] The shape of the particles is not particularly limited as long as it satisfies the objectives of the present invention, and spherical particles and irregular, non-spherical particles can be used. The particle diameter of irregular particles can be calculated as the equivalent circle diameter. The equivalent circle diameter is the value obtained by dividing the observed particle area by π, calculating the square root, and then multiplying it by two.

[0060] The ratio of particles to the total solid content of the lubricating layer is preferably 150% by mass or less, more preferably 100% by mass or less, and even more preferably 50% by mass or less. If the ratio of particles to the total solid content of the lubricating coating layer is 150% by mass or less, transparency is maintained and particle detachment from the lubricating layer does not occur significantly, which is preferable.

[0061] The ratio of particles to the total solid content of the lubrication layer is preferably 1% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2% by mass or more. If the ratio of particles to the total solid content of the lubrication layer is 1% by mass or more, lubricity can be ensured, which is preferable.

[0062] The particle content of the lubrication layer can be measured, for example, when the lubrication layer contains organic resin and inorganic particles. First, the lubrication layer provided on the processed film is extracted from the processed film using a solvent or the like and dried to remove the lubrication layer. Next, the obtained lubrication layer is heated, and the organic components contained in the lubrication layer are burned off by heat, thereby obtaining only the inorganic components. The mass percentage of particles contained in the lubrication layer can be determined by measuring the weight of the obtained inorganic components and the lubrication layer before combustion and removal. This can be measured accurately using a commercially available differential thermal and thermogravimetric simultaneous analyzer. Note that if multiple types of particles are present, the ratio of the above particles to the total solid content of the lubrication layer refers to the combined ratio of the multiple types.

[0063] The lubrication layer may contain a crosslinking agent to harden the binder resin. The crosslinking agent is not particularly limited, but examples include isocyanate, melamine, carbodiimide, and oxazoline. The content of the crosslinking agent is preferably 50% by mass or less, and more preferably 30% by mass or less, relative to 100% by mass of the binder resin.

[0064] When the lubrication layer contains a crosslinking agent, it is preferable that the crosslinking is completely completed after coating on the resin sheet and before the laminate film is wound up. If unreacted crosslinking agent is present, there is a concern that the unreacted crosslinking agent will react and cause blocking between the back surface of the base film and the lubrication layer during winding and storage as a laminate film. Therefore, it is preferable that the lubrication layer does not contain any crosslinking agent or that the crosslinking agent is completely reacted. In one embodiment, the lubricious layer is substantially free of crosslinking agents.

[0065] The lubrication layer may contain a surfactant to improve leveling during coating and to defoam the coating solution. The surfactant may be cationic, anionic, or nonionic, but silicone, acetylene glycol, or fluorine-based surfactants are preferred. These surfactants are preferably contained in the coating layer to an extent that excessive addition does not cause abnormalities in the coating appearance.

[0066] The thickness (t2) of the lubrication layer is 0.001 μm or more and 1 μm or less. More preferably, it is 0.01 μm or more and 0.5 μm or less, and even more preferably, it is 0.01 μm or more and 0.2 μm or less. Furthermore, the thickness (t2) of the lubrication layer is 20% or less of the thickness (t1) of the resin sheet, more preferably 10% or less, and even more preferably 5% or less. When the film thickness (t2) of the lubrication layer satisfies the above range, the resin sheet with the lubrication layer peeled from the base film has both good slip properties and resin sheet performance, for example, high transparency for optical applications and electrical properties for electronic components such as film capacitors, which is preferable.

[0067] The film thickness of the lubricating layer is not particularly limited and can be measured by a known method, but can be measured using an optical interference type film thickness meter or by observing and measuring the cross section with a scanning electron microscope or a transmission electron microscope, etc. Since the film thickness of the lubricating layer is thin, it is preferable to observe and measure the cross section of the laminated film with a scanning electron microscope or a transmission electron microscope.

[0068] The lubrication layer of the present invention is preferably formed by coating a coating solution prepared by dissolving or dispersing the materials constituting the lubrication layer in an organic solvent or water using a solution casting method onto a resin sheet formed on the substrate film. Similar to the coating methods for release layers and resin sheets, the coating can be performed using known methods. For example, conventionally known methods such as roll coating methods such as gravure coating and reverse coating, bar coating using a wire bar, die coating, spray coating, and air knife coating can be used. The lubrication layer can be applied immediately after the resin sheet is coated and dried on the substrate film, or it can be wound into a roll and then rewound for coating. In the above-mentioned method, continuous processing can be performed using a coating device with two coating and drying processes. In the below-mentioned method, the layer can be formed by sequentially processing twice using a device with one coating and drying process. Alternatively, the resin sheet and the lubrication layer can be simultaneously coated onto the substrate film using a multilayer coater die or the like.

[0069] (Laminated film) The laminated film of the present invention is used after the resin sheet with the lubricating layer is peeled from the substrate film in the next step or later. Therefore, it is preferable that the peeling force from the substrate film is 800 mN / 25 mm width or less, because the resin sheet with the lubricating layer can be peeled without breaking. It is more preferable that the peeling force is 500 mN / 25 mm width or less, for example, 300 mN / 25 mm width or less, and even more preferable that the peeling force is 100 mN / 25 mm width or less. The peeling force varies depending on the resin sheet to be laminated, and can be adjusted by the type of release layer of the substrate film and the presence or absence of a release layer.

[0070] As described above, the present invention comprises a resin sheet and an easy-to-slip layer according to the present invention, the film thickness (t2) of the easy-to-slip layer has a predetermined relationship with the film thickness (t1) of the resin sheet, the arithmetic mean height (Sa) of the surface of the base film on which the resin sheet is laminated is 20 nm or less, the maximum protrusion height (P) is 200 nm or less, and the peel force when peeling the resin sheet with the easy-to-slip layer from the base film is 800 mN / 25 mm width or less, so that pinholes and local thickness unevenness are less likely to occur in the resin sheet. Furthermore, by satisfying the conditions of the present invention, the present invention can exhibit the performance of the resin sheet described above, for example, high transparency for optical applications, and excellent electrical properties for electronic components such as film capacitors. [Example]

[0071] The present invention will now be described in detail using examples and comparative examples, but the present invention is not limited to the following examples. The evaluation methods used in the present invention are as follows.

[0072] (Arithmetic mean height (Sa), maximum projection height (P)) The values ​​were measured under the following conditions using a non-contact surface shape measurement system (VertScan R550H-M100, manufactured by Ryoka Systems Co., Ltd.). The arithmetic mean height (Sa) was calculated by averaging five measurements, and the maximum protrusion height (P) was calculated by measuring seven times and excluding the maximum and minimum values, using the maximum of the five measurements. (Measurement conditions) Measurement mode: WAVE mode Objective lens: 10x 0.5x Tube Lens ·Measurement area 936μm×702μm (Analysis conditions) Surface correction: 4th order correction Interpolation: Full interpolation Filtering: Gaussian cutoff value 50μm

[0073] (film thickness) The cut-out laminated film was embedded in resin and cut into ultrathin sections using an ultramicrotome. Then, it was directly observed at a magnification of 20,000 times using a JEOL JEM2100 transmission electron microscope, and the thickness of each layer of the laminated film was measured from the observed TEM images.

[0074] (peel force) The laminated film was cut into strips 25 mm wide and 150 mm long, one end of the base film was fixed, one end of the resin sheet was supported, and the resin sheet side was pulled at a speed of 300 mm / min to measure the T-peel strength. A tensile tester (Shimadzu Corporation's "AUTOGRAPH AG-X") was used for the measurement. The measured value was the average of five measurements. The peelability was evaluated based on the measured peel force according to the following criteria. 〇: Peeling was possible with a low peeling force of 100 mN / 25 mm width or less, and even thin films could be peeled off without tearing. ◯△: Peeling was possible with a peeling force of 300 mN / 25 mm width or less, and greater than 100 mN / 25 mm width. △: Peeling was possible when the peeling force was greater than 300 mN / 25 mm width and less than 800 mN / 25 mm width. In areas where the film was extremely thin, some tearing occurred. ×: Unable to peel off.

[0075] (blocking) The front and back sides of the obtained laminated film were overlapped, and a load of 1 kg / cm 2 was applied at 40° C. for 24 hours. After that, the film was peeled off and the state was visually observed and evaluated as follows. ◯: No particular marks remained after peeling and peeling was possible without any problems. △: Peeling was possible, but slight marks remained on the film after peeling. ×: The films stuck together and could not be peeled off.

[0076] (Slipperiness) The resin sheet (including the slippery layer) peeled from the base film was placed on its front and back sides and slid by hand while removing the air between the films. The condition was evaluated according to the following criteria. Good: The films did not stick together and slid. Good and Bad: The films slid smoothly, but there was some sticking. △: The films slid smoothly but there was some snagging. ×: The films did not slide at all.

[0077] (Optical properties) The haze and total light transmittance of the resin sheet peeled from the substrate film were measured using a haze meter (NDH7000II, manufactured by Nippon Denshoku Industries Co., Ltd.) and evaluated according to the following criteria. 〇: Very high transparency (haze less than 1%) △: High transparency (haze 1-2%) ×: Low transparency (haze greater than 2%)

[0078] (Electrical characteristics) A thin aluminum vapor-deposited layer was formed on both sides of the resin sheet peeled from the base film, and the dielectric breakdown voltage (V / μm) was measured at room temperature. The average value of 10 measurements was used and evaluated according to the following criteria. ○: Dielectric breakdown voltage (BDV value) is 300V / μm or more △: Breakdown voltage is 200V / μm or more ×: Breakdown voltage is less than 200V / μm

[0079] (Preparation of polyethylene terephthalate pellets (PET(I))) The esterification reactor used was a continuous esterification reactor consisting of a three-stage complete mixing vessel equipped with a stirrer, a partial condenser, a raw material inlet, and a product outlet. The TPA (terephthalic acid) was fed at 2 tons / h, EG (ethylene glycol) at 2 moles per mole of TPA, and antimony trioxide at a concentration that would result in 160 ppm Sb atoms in the PET produced. The resulting slurry was continuously fed into the first esterification reactor and reacted at 255°C for an average residence time of 4 hours at atmospheric pressure. Next, the reaction product in the first esterification reactor was continuously removed from the system and fed to a second esterification reactor, and EG distilled off from the first esterification reactor was fed into the second esterification reactor in an amount of 8 mass% based on the produced PET. Further, an EG solution containing magnesium acetate tetrahydrate in an amount such that the Mg atoms would be 65 ppm based on the produced PET, and an EG solution containing TMPA (trimethyl phosphate) in an amount such that the P atoms would be 40 ppm based on the produced PET were added, and the reaction was carried out at atmospheric pressure for an average residence time of 1 hour at 260°C. Next, the reaction product in the second esterification reactor was continuously removed from the system and fed to a third esterification reactor, and the reaction was carried out at 39 MPa (400 kg / cm) using a high-pressure disperser (manufactured by Nippon Seiki Co., Ltd.). 2 0.2% by mass of porous colloidal silica (average particle size: 0.9 μm), which had been dispersed at a pressure of 1000 kJ / cm² for an average number of passes (5 times), and 0.4% by mass of synthetic calcium carbonate (average particle size: 0.6 μm), each containing 1% by mass of ammonium salt of polyacrylic acid per calcium carbonate, were added as 10% EG slurry and reacted at atmospheric pressure for an average residence time of 0.5 hours at 260°C. The esterification reaction product produced in the third esterification reactor was continuously fed to a three-stage continuous polycondensation reactor for polycondensation. The product was filtered through a filter made of sintered stainless steel fibers with a 95% cutoff diameter of 20 μm, then ultrafiltered and extruded into water. After cooling, the product was cut into chips to yield PET chips with an intrinsic viscosity of 0.60 dL / g (hereinafter abbreviated as PET(I)). The lubricant content in the PET chips was 0.6% by mass.

[0080] (Preparation of polyethylene terephthalate pellets (PET(II))) On the other hand, in the above-mentioned production of PET chips, PET chips containing absolutely no particles such as calcium carbonate or silica and having an intrinsic viscosity of 0.62 dl / g were obtained (hereinafter abbreviated as PET(II)).

[0081] (Preparation of polyethylene terephthalate pellets (PET(III))) PET chips were obtained in the same manner as PET(I), except that the type and content of PET(I) particles were changed to 0.75% by mass of synthetic calcium carbonate with an average particle size of 0.9 μm, to which ammonium salt of polyacrylic acid was attached at 1% by mass per calcium carbonate (hereinafter referred to as PET(III)). The lubricant content in the PET chips was 0.75% by mass.

[0082] (Production of base film X1) These PET chips were dried and then melted at 285°C. Then, the melts were melted at 290°C in separate melt extruders. The melts were then filtered through two filters: one containing sintered stainless steel fibers with a 95% cutoff diameter of 15 μm, and the other containing sintered stainless steel particles with a 95% cutoff diameter of 15 μm. The resulting mixtures were then combined in a feedblock, where PET(I) was laminated as surface layer B and PET(II) as surface layer A. The resulting laminate was extruded (cast) at a speed of 45 m / min and electrostatically bonded and cooled on a casting drum at 30°C to obtain an unstretched polyethylene terephthalate sheet with an intrinsic viscosity of 0.59 dl / g. The layer ratio was adjusted to PET(I) / PET(II) = 60% / 40% based on the extrusion rate calculations. The unstretched sheet was then heated with an infrared heater and stretched 3.5 times in the machine direction at a roll temperature of 80°C using a roll speed differential. The film was then introduced into a tenter and stretched 4.2 times in the transverse direction at 140°C. It was then heat-treated at 210°C in a heat-setting zone. It was then relaxed in the transverse direction at 170°C by 2.3%, yielding a biaxially stretched polyethylene terephthalate film substrate film X1 with a thickness of 25 μm. The surface layer A of the obtained film X1 had an Sa of 2 nm, and the surface layer B had an Sa of 29 nm.

[0083] (Production of base film X2) The release coating solution described below was applied to the surface layer A of the base film X1 obtained above by reverse gravure coating so that the wet film thickness was 5 μm, and then dried and cured in a hot air drying oven at 120° C. for 30 seconds to obtain a base film X2 with a release layer. The surface roughness Sa of the release layer was 2 nm. (Release coating liquid) Toluene 48 parts by mass Methyl ethyl ketone 48 parts by mass LTC310 (Dow-Toray heat-curing silicone coating, solid content 30 wt%) 3 parts by mass SRX212P Catalyst (Pt-based curing catalyst manufactured by Dow-Toray) 0.1 part by mass

[0084] (Production of base film X3) The layer structure and stretching conditions were the same as for base film X1, but the thickness was adjusted by changing the casting speed to produce a biaxially stretched polyethylene terephthalate film with a thickness of 12 μm. A release layer similar to that for X2 was then provided to obtain base film X3. The surface layer A of the resulting film X3 had an Sa of 3 nm, and the surface layer B had an Sa of 29 nm.

[0085] (Base film x4) The base film X4 used was a 25 μm-thick A4100 (Cosmoshine (registered trademark), manufactured by Toyobo Co., Ltd.) with a release layer similar to that of X2 provided on the surface layer A. A4100 does not substantially contain particles in the film, and a coating layer containing particles is provided by in-line coating only on the surface layer B side. The surface layer A of the base film X4 had an Sa of 1 nm, and the surface layer B had an Sa of 2 nm.

[0086] (Base film x5) The base film X5 used was a 25 μm-thick E5101 (Toyobo Ester (registered trademark) film, manufactured by Toyobo Co., Ltd.) with a release layer similar to that of X2 provided on the surface layer A. E5101 is configured so that particles are contained in the surface layers A and B of the film. The surface layer A of the base film X5 had an Sa of 25 nm, and the surface layer B had an Sa of 25 nm.

[0087] Example 1 Resin solution (1) was applied to the surface layer A of the substrate film X1 using a reverse gravure coating method so that the thickness of the resin sheet after drying would be 3 μm, and the resin sheet was formed by drying at 120°C for 30 seconds in a hot air drying oven. Subsequently, the lubrication layer coating solution A was applied to the resin sheet using a reverse gravure coating method so that the thickness of the lubrication layer after drying would be 50 nm, and the resin sheet was dried at 100°C for 30 seconds in a hot air drying oven to form a lubrication layer on the resin sheet, producing a laminate film. The resin sheet with the lubrication layer was then evaluated for peel force when peeled from the substrate film and for slip properties after peeling. (Resin solution 1) Toluene 7 parts by mass Tetrahydrofuran 20 parts by mass TOPAS (registered trademark) 6017S-04 toluene solution 75 parts by mass (Cycloolefin resin manufactured by Polyplastics, solid content 20wt%) The solution was prepared by mixing cycloolefin resin and toluene and heating the mixture. Surfactant 0.1 parts by mass

[0088] (Easy slip layer solution A) Toluene 75 parts by mass Tetrahydrofuran 20 parts by mass TOPAS (registered trademark) 6017S-04 toluene solution 5 parts by mass (Cycloolefin resin manufactured by Polyplastics, solid content 20wt%) TOL-ST 0.5 parts by mass (Nissan Chemical, silica particle dispersion, solid content 40 wt%, particle size 12 nm)

[0089] Example 2 A laminated film was produced in the same manner as in Example 1, except that the base film X1 was changed to the base film X2 with a release layer.

[0090] (Examples 3 to 5, Comparative Example 1) A laminated film was prepared in the same manner as in Example 2, except that the thickness of the lubricity layer was changed as shown in Table 1.

[0091] From the results of Examples 1 to 5 and Comparative Example 1, it was confirmed that the provision of a lubrication layer provided good lubrication of the resin sheet without adding particles to the resin sheet. When the thickness of the lubrication layer was changed, both the lubrication property and transparency were good up to a certain thickness, but it was found that when the thickness t2 of the lubrication layer became as large as about 26.7% of the thickness (t1) of the resin sheet, as in Comparative Example 1, the transparency of the resin sheet was affected.

[0092] Example 6 A laminated film was prepared in the same manner as in Example 2, except that the lubricity layer was changed to the lubricity layer coating solution B in which the amount of particles added was changed. (Easy slip layer solution B) Toluene 75 parts by mass Tetrahydrofuran 20 parts by mass TOPAS (registered trademark) 6017S-04 toluene solution 5 parts by mass (Cycloolefin resin manufactured by Polyplastics, solid content 20wt%) TOL-ST 0.1 part by mass (Nissan Chemical, silica particle dispersion, solid content 40 wt%, particle size 12 nm)

[0093] Example 7 A laminated film was produced in the same manner as in Example 2, except that the lubricity layer coating solution was changed to lubricity layer coating solution C in which the amount of particles added to the lubricity layer was changed. (Easy slip layer solution C) Toluene 75 parts by mass Tetrahydrofuran 20 parts by mass TOPAS (registered trademark) 6017S-04 toluene solution 5 parts by mass (Cycloolefin resin manufactured by Polyplastics, solid content 20wt%) TOL-ST 1.3 parts by mass (Nissan Chemical, silica particle dispersion, solid content 40 wt%, particle size 12 nm)

[0094] In Examples 6 and 7, in which the amount of particles added to the lubrication layer was changed, there was no problem with the lubrication properties. Example 7, which contained a larger amount of particles, tended to have slightly improved lubrication properties.

[0095] (Examples 8 and 9) Except for changing the thickness of the resin sheet to that shown in the table, a laminated film was produced in the same manner as in Example 2. The resin sheet had good slip properties even when the thickness was changed.

[0096] Example 10 Resin solution (2) was applied to the surface layer A of the base film X1 using a reverse gravure coating method so that the thickness of the resin sheet after drying would be 3 μm, and the resin sheet was formed by drying at 120°C for 30 seconds in a hot air drying oven. Subsequently, lubrication layer coating solution D was applied to the resin sheet using a reverse gravure coating method so that the thickness of the lubrication layer after drying would be 50 nm, and the resin sheet was dried at 100°C for 30 seconds in a hot air drying oven to form a lubrication layer on the resin sheet, producing a laminate film. The peel force when peeling the resin sheet with the lubrication layer from the resulting laminate film and the slipperiness after peeling were evaluated. (Resin solution 2) Methyl ethyl ketone 31 parts by mass Tetrahydrofuran 31 parts by mass PKHB solution 38 parts by mass (Gabriel Phenoxies Phenoxy resin, solid content 40wt%) *The solution was prepared by dissolving phenoxy resin in tetrahydrofuran. BYK-370 0.6 parts by mass (Byk Chemie Japan, silicone surfactant)

[0097] (Easy slip layer solution D) Methyl ethyl ketone 48 parts by mass Tetrahydrofuran 48 parts by mass PKHB solution 2.5 parts by mass (Gabriel Phenoxies, phenoxy resin, solid content 40wt%) MEK-ST-ZL 0.7 parts by mass (Nissan Chemical, silica particle dispersion, solid content 30 wt%, particle size 80 nm) BYK-370 0.04 parts by mass (Byk Chemie Japan, silicone surfactant)

[0098] Example 11 A laminated film was produced in the same manner as in Example 10, except that the base film X1 was changed to the base film X2 with a release layer.

[0099] Example 12 A laminated film was produced in the same manner as in Example 11, except that Resin Solution 3 was used. (Resin solution 3) Methyl ethyl ketone 34 parts by mass Tetrahydrofuran 34 parts by mass PKHB solution 28 parts by mass (Gabriel Phenoxies Phenoxy resin, solid content 40wt%) *The solution was prepared by dissolving phenoxy resin in tetrahydrofuran. Millionate MR-200 3.8 parts by mass (Tosoh Corporation, isocyanate crosslinking agent, solid content 99wt%) BYK-370 0.6 parts by mass (Byk Chemie Japan, silicone surfactant)

[0100] In Examples 10 to 12, the resin type of the resin sheet and the lubrication layer was changed, and a comparison was made between the presence and absence of a release layer on the base film. Examples 10 and 11, in which the resin sheet did not contain a crosslinking agent, showed good releasability whether or not the base film had a release layer. Furthermore, Example 13, in which the resin sheet contained a crosslinking agent, showed good releasability because the base film had a release layer. It was found that when the resin sheet contained a crosslinking agent, it was preferable for the base film to have a release layer.

[0101] Example 13 A laminated film was prepared in the same manner as in Example 12, except that the amount of added particles was changed to the lubricity layer solution E below. (Easy layer solution E) Methyl ethyl ketone 48 parts by mass Tetrahydrofuran 48 parts by mass PKHB solution 2.5 parts by mass (Gabriel Phenoxies Phenoxy resin, solid content 40wt%) MEK-ST-ZL 1.7 parts by mass (Nissan Chemical, silica particle dispersion, solid content 30 wt%, particle size 80 nm) BYK-370 0.04 parts by mass (Byk Chemie Japan, silicone surfactant)

[0102] Example 14 A laminated film was prepared in the same manner as in Example 12, except that the amount of added particles was changed to the lubricity layer solution E below. (Easy slip layer solution F) Methyl ethyl ketone 47 parts by mass Tetrahydrofuran 47 parts by mass PKHB solution 2.5 parts by mass (Gabriel Phenoxies Phenoxy resin, solid content 40wt%) MEK-ST-ZL 3.3 parts by mass (Nissan Chemical, silica particle dispersion, solid content 30 wt%, particle size 80 nm) BYK-370 0.04 parts by mass (Byk Chemie Japan, silicone surfactant)

[0103] The amount of particles contained in the lubrication layer was investigated in Examples 12 to 14. The results showed that there were no problems with lubrication properties or transparency even when the amount was changed within the range shown in the examples.

[0104] Example 15 A laminated film was prepared in the same manner as in Example 12, except that the particle size was changed to the following lubrication layer solution G. (Easy slip layer solution G) Methyl ethyl ketone 48 parts by mass Tetrahydrofuran 48 parts by mass PKHB solution 2.5 parts by mass (Gabriel Phenoxies Phenoxy resin, solid content 40wt%) MEK-ST-L 0.7 parts by mass (Nissan Chemical, silica particle dispersion, solid content 30 wt%, particle size 45 nm) BYK-370 0.04 parts by mass (Byk Chemie, silicone surfactant)

[0105] Example 16 A laminated film was prepared in the same manner as in Example 12, except that the particle size was changed to the lubrication layer solution H. (Easy slip layer solution H) Methyl ethyl ketone 48 parts by mass Tetrahydrofuran 48 parts by mass PKHB solution 2.5 parts by mass (Gabriel Phenoxies Phenoxy resin, solid content 40wt%) MEK-ST-2040 0.5 parts by mass (Nissan Chemical, silica particle dispersion, solid content 40 wt%, particle size 200 nm) BYK-370 0.04 parts by mass (Byk Chemie, silicone surfactant)

[0106] Example 17 A laminated film was prepared in the same manner as in Example 12, except that the particle diameter was changed to the following lubrication layer solution I. (Easy slip layer solution I) Methyl ethyl ketone 50 parts by mass Tetrahydrofuran 50 parts by mass PKHB solution 2.5 parts by mass (Gabriel Phenoxies Phenoxy resin, solid content 40wt%) Eposter (registered trademark) MA1002 0.2 parts by weight (Nippon Shokubai, acrylic particles, particle size 2 μm) BYK-370 0.04 parts by mass (Byk Chemie, silicone surfactant)

[0107] In Examples 15 to 17, changes in the particle size of the particles contained in the lubrication layer were investigated. Good lubrication properties were obtained even when the particle size was changed within the range of the examples, but when 2 μm particles were used in Example 17, transparency tended to decrease slightly.

[0108] Example 18 A laminated film was prepared in the same manner as in Example 12, except that the lubricity layer was changed to the lubricity layer coating liquid J containing a crosslinking agent. (Easy slip layer solution J) Methyl ethyl ketone 48 parts by mass Tetrahydrofuran 48 parts by mass PKHB solution 1.9 parts by mass (Gabriel Phenoxies Phenoxy resin, solid content 40wt%) Millionate MR-200 0.3 parts by mass (Tosoh Corporation, isocyanate crosslinking agent, solid content 99wt%) MEK-ST-ZL 0.7 parts by mass (Nissan Chemical, silica particle dispersion, solid content 30 wt%, particle size 80 nm) BYK-370 0.04 parts by mass (Byk Chemie, silicone surfactant) Even when the slip layer contained a crosslinking agent, there were no problems with release properties or slipperiness, but the blocking evaluation tended to be somewhat poor. This indicates that it is preferable for the slip layer not to contain a crosslinking agent.

[0109] (Examples 19 and 20, Comparative Example 2) A laminated film was prepared in the same manner as in Example 12, except that the base film was changed to one shown in the table. Evaluation was performed using substrate films with different surface roughness. Examples 19 and 20, which had low Sa and P, showed good results, but Comparative Example 3, which had high Sa and P, showed unevenness on the resin sheet after peeling, raising concerns about deterioration of electrical properties when used in electronic components.

[0110] (Comparative Example 3) A laminated film was produced in the same manner as in Example 2, except that no lubrication layer was provided.

[0111] Comparative Example 4 A laminated film was prepared in the same manner as in Example 12, except that no lubrication layer was provided.

[0112] Comparative Examples 4 and 5, which did not have a lubrication layer, had poor lubrication properties and were unable to exhibit the functions of the resin sheet of the present invention in electronic parts and optical applications.

[0113] The following table shows the evaluation results of various conditions and physical properties of the films used in the examples and comparative examples.

[0114] [Table 1A]

[0115] [Table 1B]

[0116] [Table 2A]

[0117] [Table 2B] [Industrial Applicability]

[0118] The present invention relates to a laminated film having a resin sheet laminated thereon, and more particularly to a laminated film having a resin sheet laminated thereon that is used for electronic components and optical applications. [Explanation of symbols]

[0119] 10 Base film 11 Release layer 12 Resin sheet 13 Easy slip layer 14 particles

Claims

1. A laminated film obtained by laminating a resin sheet and a lubricating layer in this order on at least one surface of a base film, the base film being made of a polyester film, and satisfying the following: The resin sheet has a haze of 2% or less, or The resin sheet has a breakdown voltage of 200 V / μm or more, The film thickness (t1) of the resin sheet is 1 μm or more and 20 μm or less, The slip layer contains at least a binder resin and particles, The thickness (t2) of the slip layer is 0.001 μm or more and 1 μm or less, The thickness (t2) of the slip layer is 20% or less of the thickness (t1) of the resin sheet, and The peel force when peeling the resin sheet with the lubricating layer from the base film is 800 mN / 25 mm width or less. Laminated film.

2. 2. The laminated film according to claim 1, further comprising a release layer between the substrate film and the resin sheet.

3. 2. The laminated film according to claim 1, wherein the binder component contained in the lubrication layer is the same as the main resin component contained in the resin sheet.

4. 2. The laminated film according to claim 1, wherein the lubricity layer is substantially free of a crosslinking agent.

5. the substrate film has a surface layer A on the surface facing the resin sheet, 2. The laminate film according to claim 1, wherein the surface layer A is a layer that is substantially free of particles, has an arithmetic mean height (Sa) of 20 nm or less, and a maximum projection height (P) of 200 nm or less.

6. 6. A method for producing the laminated film according to claim 1, comprising coating a resin sheet and a lubricity layer in this order on a substrate film by a solution casting method.

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