KR20230116054A - Laminated film and manufacturing method of the laminated film - Google Patents

Abstract

[Problem] The present invention is to provide a laminated film capable of providing a resin sheet that is highly smooth and has good slipperiness.
[Solution] A polyester base film, a release layer disposed on at least one surface of the base film, and a resin sheet disposed on the surface opposite to the substrate in the release layer A laminated film having a laminated film and satisfying the following conditions: The resin sheet is obtained by curing a resin sheet forming composition containing at least a resin component (A) and a crosslinking agent (B), and the resin sheet is substantially free of particles, The film thickness (t1) of the resin sheet is 1 μm or more and 20 μm or less, the arithmetic mean height Sa of the surface 1 of the resin sheet is 2 nm or more and 30 nm or less, and the maximum cross-sectional height of the surface 1 of the resin sheet (St) is 80 nm or more and 1000 nm or less, the static friction measured by overlapping the surface (1) on the side opposite to the surface of the release layer in the resin sheet and the surface (2) on the side of the release layer in the resin sheet. A coefficient is 1.5 or less.

Description

Laminated film and manufacturing method of the laminated film

The present invention relates to a laminated film in which resin sheets are laminated. In particular, it relates to a laminated film in which resin sheets used for electronic components and optical applications are laminated.

Conventionally, a release film using a polyester film as a base material has high heat resistance and mechanical properties, and is used in solution film formation of resin sheets such as adhesive sheets, cover films, polymer electrolyte membranes, and dielectric resin sheets. It has been used as a process film to be used. In recent years, since high smoothness and transparency are required for electronic components such as dielectric resin sheets used in film capacitors and resin sheets used for optical applications, high smoothness has also been required for the surface of release films used as process films. . Therefore, techniques as described in Patent Literatures 1 to 3 are disclosed, and what made the surface roughness of the surface of a mold release layer low is proposed.

However, for example, in optical applications, while high smoothness is required in order to increase transparency, etc., high smoothness deteriorates slipperiness, and there is a risk that a yield may be reduced due to scratches in a conveyance step or the like. In addition, in electronic component applications such as film capacitor applications, smoothness is required to improve electrical characteristics such as dielectric breakdown voltage, while excessively high smoothness results in poor slipperiness, and it is difficult to wind a dielectric resin sheet in a roll shape. At times, misalignment of the winding, incorporation of wrinkles, etc. may occur, and the performance of the film capacitor may deteriorate due to poor winding.

In order to improve these, Patent Document 4 proposes adding specific particles to a resin sheet used for optics, such as a polarizing plate, to give slipperiness. Further, Patent Literature 5 proposes a method of transferring particles on a base film to a resin sheet used for a film for a film capacitor or the like.

Japanese Patent Laid-Open No. 2012-144021 Japanese Patent Laid-Open No. 2014-154273 Japanese Patent Laid-Open No. 2015-182261 Japanese Patent Laid-Open No. 2019-95661 International Publication No. 2020/039638

However, in the method of Patent Literature 4, since particles are included in the resin sheet, there is a possibility that the internal haze rises and the transparency becomes insufficient. Further, in the method of Patent Literature 5, there is a fear that the amount of particles transferred to the resin sheet may become non-uniform, resulting in unstable slipperiness.

The present invention solves the above problems and proposes a laminated film capable of providing a resin sheet that is highly smooth and has good slipperiness without substantially adding particles to the inside of the resin sheet.

As a result of intensive studies, the inventors of the present invention applied a coating solution containing at least a specific resin and a crosslinking agent on a smooth base film under specific conditions, dried and cured, so that the surface of the laminated film was damaged ( Phase) found to form unevenness due to the separable structure, and succeeded in imparting good slipperiness without containing particles or the like.

That is, the present invention consists of the following configurations.

[1] a polyester base film, a release layer disposed on at least one side of the base film, and a resin sheet disposed on the surface opposite to the substrate in the release layer,

A laminated film satisfying the following (1) to (6):

(1) The resin sheet is obtained by curing a resin sheet forming composition containing at least a resin component (A) and a crosslinking agent (B),

(2) The resin sheet contains substantially no particles,

(3) The film thickness (t1) of the resin sheet is 1 μm or more and 20 μm or less,

(4) the arithmetic mean height (Sa) of the surface (1) of the resin sheet is 2 nm or more and 30 nm or less;

(5) The maximum cross-sectional height (St) of the surface (1) of the resin sheet is 80 nm or more and 1000 nm or less,

(6) The static friction coefficient measured by overlapping the surface 1 on the side opposite to the surface of the release layer in the resin sheet and the surface 2 on the side of the release layer in the resin sheet is 1.5 or less.

[2] In one aspect, the crosslinking agent (B) contained in the resin sheet forming composition is a liquid at 30°C.

[3] In one aspect, the ratio of the crosslinking agent (B) contained in the resin sheet to the entire resin sheet is 10% by mass or more.

[4] In one aspect, the weight average molecular weight of the resin component (A) contained in the resin sheet is 10000 or more.

[5] In one aspect, the surface free energy of the surface of the release layer is 40 mJ/m 2 or less, and the adhesion energy is 3.5 mJ/m 2 or more.

[6] In one aspect, the arithmetic mean height (Sa) of the release layer side surface of the base film is 20 nm or less, and the maximum protrusion height (P) is 500 nm or less.

[7] In another embodiment, the present invention provides a method for producing a laminated film according to any of the above, and the production method includes coating and molding a resin sheet on a base film by a solution film forming method. .

By using the laminated film of the present invention, a resin sheet having both high smoothness and good slipperiness can be provided, and by using the resin sheet molded in the present invention, good products can be provided for various uses.

1 is a schematic cross-sectional view showing the configuration of the present invention.
Fig. 2 is a schematic cross-sectional view illustrating the configuration of the present invention in one embodiment.

As shown in FIG. 1, the laminated|multilayer film of this invention consists of the polyester base film 10, the release layer 11 arrange|positioned on at least one surface of the base film 10, and the release layer 11 It is a laminated film having a resin sheet 12 arranged on the surface on the opposite side to the base film 10 of .

INDUSTRIAL APPLICABILITY The present invention is a resin sheet capable of enhancing transparency and the like in optical applications, for example, and can provide a resin sheet exhibiting high smoothness. Furthermore, it is possible to achieve both high smoothness and high slipperiness, which have been difficult in the past, and, for example, it is possible to suppress the occurrence of scratches in the conveyance step and the like, and the decrease in yield can be avoided.

In addition, for example, in electronic component applications such as film capacitor applications, a resin sheet exhibiting high smoothness can be provided, and the resin sheet can improve electrical properties such as dielectric breakdown voltage. In addition, it is possible to achieve both high smoothness and high slipperiness, which have been difficult in the past, and, for example, when winding a dielectric resin sheet into a roll shape, it is possible to suppress misalignment of the winding and mixing of wrinkles, etc., and exhibit good winding properties. can For this reason, conveyance or the like is possible while maintaining excellent capacitor performance.

Further, in the present invention, the resin sheet does not substantially contain particles, and it is possible to avoid insufficient transparency such as an increase in internal haze. In addition, the problem of non-uniformity in the amount of particles transferred to the resin sheet can be avoided, and good slipperiness can be exhibited.

(substrate film)

The present invention has a polyester-based base film. The polyester constituting the polyester film used as the base material of the present invention is not particularly limited, and a film formed of polyester commonly used as a base film can be used. Preferably, it is a crystalline linear saturated polyester composed of an aromatic dibasic acid component and a diol component, and examples thereof include polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, Polytrimethylene terephthalate or a copolymer mainly composed of constituents of these resins is more suitable. In particular, polyester films formed from polyethylene terephthalate are particularly suitable.

In polyethylene terephthalate, the repeating unit of ethylene terephthalate is preferably 90 mol% or more, more preferably 95 mol% or more, and other dicarboxylic acid components and diol components may be copolymerized in small amounts. In terms of cost, it is preferable to use only terephthalic acid and ethylene glycol. In addition, known additives such as antioxidants, light stabilizers, ultraviolet absorbers, and crystallizers may be added within a range that does not impair the effect of the film of the present invention. The polyester film is preferably a biaxially oriented polyester film for reasons such as a high elastic modulus in both directions.

The intrinsic viscosity of the polyethylene terephthalate film is preferably 0.50 to 0.70 dl/g, and more preferably 0.52 to 0.62 dl/g. When the intrinsic viscosity is 0.50 dl/g or more, breakage does not occur much in the stretching step, which is preferable. Conversely, when it is 0.70 dl/g or less, the cutting property at the time of cutting to a predetermined product width is good, and dimensional defects do not occur, which is preferable. Moreover, it is preferable to fully vacuum dry raw material pellets.

The manufacturing method of the polyester film in this invention is not specifically limited, Conventionally, the method generally used can be used. For example, it can be obtained by melting the polyester with an extruder, extruding it into a film form, cooling it with a rotating cooling drum to obtain an unstretched film, and stretching the unstretched film. As for the stretching, it is preferable that it is biaxial stretching in terms of mechanical properties and the like. The biaxially stretched film can be obtained by sequentially biaxially stretching a vertically or horizontally uniaxially stretched film in the horizontal or vertical direction, or by simultaneously biaxially stretching an unstretched film in the vertical and horizontal directions. there is.

In the present invention, the stretching temperature at the time of stretching the polyester film is preferably equal to or higher than the secondary transition point (Tg) of polyester. It is preferable to perform stretching 1 to 8 times, particularly 2 to 6 times in each of the vertical and horizontal directions.

The polyester film preferably has a thickness of 6 μm or more and 50 μm or less, more preferably 8 μm or more and 31 μm or less, and more preferably 10 μm or more and 28 μm or less. When the thickness of the film is 6 μm or more, there is no fear of deformation due to heat during production of the film, processing of the release layer, molding of the resin sheet, etc., which is preferable. On the other hand, when the thickness of the film is 50 μm or less, the roll diameter when wound into a roll shape is small and the roll length of the resin sheet to be molded can be increased, so it is preferable.

When the polyester film as a base film has a multilayer structure described later, the film thickness of the entire base film falls within the above range.

The polyester film may be a single layer or a multilayer of two or more layers. It is preferable to have a surface layer A substantially free of particles on at least one side. 1 aspect WHEREIN: The polyester film which is a base film has the surface layer A on the surface on the resin sheet side. When the base film is a laminated polyester film having a multilayer structure of two or more layers, it is preferable to have a surface layer B that can contain particles or the like on the opposite side of the surface layer A that does not substantially contain particles. As for the laminate configuration, if the surface layer A is the layer on which the resin sheet is placed, the surface layer B is the layer on the opposite side, and the layer C is the core layer other than these, the layer configuration in the thickness direction is A/B, or a laminated structure such as A/C/B.

Layer C may have a plurality of layers. Also, the surface layer B may not contain particles. In that case, it is preferable to provide a coating layer containing particles and a binder on the surface layer B in order to impart sliding properties for winding the film into a roll shape.

In the polyester film of the present invention, it is preferable that the surface layer A located on the surface on which the resin sheet is formed contains substantially no particles. Moreover, it is preferable that the arithmetic mean height (Sa) of the surface layer A of a polyester film, ie, the arithmetic mean height (Sa) of the mold release layer side surface of a base film, is 20 nm or less. Moreover, as for arithmetic mean height Sa, it is especially preferable that it is 10 nm or less. If Sa is 20 nm or less, occurrence of pinholes, local thickness unevenness, etc., hardly occurs during molding of the resin sheet, which is preferable. Although it can be said that the arithmetic mean height (Sa) of the surface layer A is so preferable that it is small, it does not matter even if it is 0.1 nm or more. Here, when a release layer or the like described below is provided on the surface layer A, the release layer preferably contains substantially no particles, and the arithmetic mean height Sa after lamination of the release layer preferably falls within the above range. . In the present invention, "substantially contains no particles" means, for example, in the case of inorganic particles, when inorganic elements are quantified by fluorescence X-ray analysis, 50 ppm or less, preferably 10 ppm or less, most preferably detection It means the content below the limit. This is because even if particles are not actively added to the film, foreign matter-derived contaminants and raw material resins or contaminants adhering to lines and equipment in the film manufacturing process may be exfoliated and mixed into the film.

The maximum projection height (P) of the surface layer A of the polyester film, that is, the maximum projection height (P) of the release layer side surface of the base film is, for example, 500 nm or less, preferably 200 nm or less, more preferably 150 nm or less, , 100 nm or less is more preferable, for example, 85 nm or less, and 50 nm or less is particularly preferable. When the maximum protrusion height P is 500 nm or less, defects such as pinholes and local thinning do not occur during formation of the resin sheet, and the yield is good, which is preferable.

It can be said that P of the surface layer A of the polyester film is so preferable that it is small, but it does not matter even if it is 1 nm or more, and it does not matter even if it is 3 nm or more. Here, when a release layer or the like described later is provided on the surface layer A, it is preferable that the maximum projection height P after the release layer is laminated falls within the above range.

In the polyester film of the present invention, the surface layer B forming the opposite side of the surface layer A preferably contains particles, particularly silica particles and/or carbonic acid, from the viewpoints of slipperiness of the film and ease of air removal. It is preferable to use calcium particles. It is preferable to contain 5000-15000 ppm with the total particle|grains as for content of the particle|grains contained in surface layer B. At this time, it is preferable that the arithmetic mean height (Sa) of the film of the surface layer B is in the range of 1 to 40 nm. More preferably, it is the range of 5-35 nm. When the total amount of silica particles and/or calcium carbonate particles is 5000 ppm or more and Sa is 1 nm or more, air can be uniformly released when the film is wound up into a roll shape, and the winding appearance is good and the flatness is good. This makes it suitable for production of resin sheets. In addition, when the total amount of silica particles and/or calcium carbonate particles is 15000 ppm or less and Sa is 40 nm or less, aggregation of the lubricant is less likely to occur and coarse protrusions are not generated. The quality is stable and desirable.

As the particles contained in the surface layer B, inactive inorganic particles and/or heat-resistant organic particles other than silica and/or calcium carbonate can be used. Although it is more preferable to use silica particles and/or calcium carbonate particles from the viewpoint of transparency and cost, examples of other inorganic particles that can be used include alumina-silica composite oxide particles, hydroxyapatite particles, and the like. Moreover, as heat-resistant organic particle|grains, crosslinked polyacrylic particle|grains, crosslinked polystyrene particle|grains, benzoguanamine type particle|grains, etc. are mentioned. In the case of using silica particles, porous colloidal silica is preferable, and in the case of using calcium carbonate particles, light calcium carbonate subjected to surface treatment with a polyacrylic acid-based polymer compound is preferable from the viewpoint of preventing the slipping of the lubricant.

The average particle diameter 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. When the average particle diameter of the particles is 0.1 μm or more, the slipperiness of the base film is good and is preferable. Moreover, when the average particle diameter is 2.0 μm or less, there is no possibility of pinholes occurring in the resin sheet due to the coarse particles of the surface layer B, which is preferable.

The surface layer B may contain two or more types of particles of different materials. Moreover, you may contain the same kind of particle|grains but different average particle diameters.

In the case where the surface layer B does not contain particles, it is preferable to provide lubricity with a coating layer containing particles on the surface layer B. Although this coating layer is not specifically limited, It is preferable to provide in-line coating applied during film formation of a polyester film. When the surface layer B does not contain particles and has a coating layer containing particles on the surface layer B, the surface of the coating layer has an arithmetic mean height for the same reason as the arithmetic mean height Sa of the surface layer B described above. (Sa) is preferably in the range of 1 to 40 nm. More preferably, it is the range of 5-35 nm.

From the viewpoint of reducing pinholes, it is preferable not to use recycled raw materials or the like in the surface layer A, which is a layer on the side where the resin sheet is provided, in order to prevent mixing of particles such as a lubricant.

It is preferable that the thickness ratio of the surface layer A, which is the layer on which the resin sheet is provided, is 20% or more and 50% or less of the total layer thickness of the base film. When it is 20% or more, it is difficult to receive the influence of particles included in the surface layer B or the like from the inside of the film, and it is easy for the arithmetic mean height Sa to satisfy the above range, which is preferable. When it is 50% or less of the thickness of the entire layer of the base film, the use ratio of the recycled raw material in the surface layer B can be increased, and the environmental load is reduced, which is preferable.

Further, from the viewpoint of economy, 50 to 90% by mass of film scraps or recycling raw materials for PET bottles can be used for layers other than the surface layer A (surface layer B or the above-mentioned intermediate layer C). Even in this case, it is preferable that the type and amount of the lubricant contained in the surface layer B, the particle size, and the arithmetic mean height (Sa) satisfy the above ranges.

In addition, a coat layer may be provided on the surface of the surface layer A and/or the surface layer B on the film before stretching or after uniaxial stretching in the film forming step to improve the adhesion of a release layer or the like applied later or to prevent charging. , corona treatment, etc. may be performed. When providing a coating layer on the surface layer A, it is preferable that the said coating layer does not contain particle|grains substantially.

(release layer)

This invention has a release layer arrange|positioned on at least one surface of a base film, and has a release layer between a base film and a resin sheet, for example. The resin constituting the release layer is not particularly limited, and silicone resins, fluororesins, alkyd resins, various waxes, aliphatic olefins, and the like can be used, and each resin can be used alone or in combination of two or more. In the case where a crosslinking agent is included in the resin sheet described later, releasability is improved by including a silicone resin, so it is preferable.

In addition, in this specification, the base material and the release layer laminate may be simply referred to as a release film.

The release layer may contain, for example, a silicone resin. Silicone resin refers to a resin having a silicone structure in the molecule, and includes curable silicone, silicone graft resin, modified silicone resin such as alkyl modification, etc. From the viewpoint of transferability, etc., it is preferable to use a reactive cured silicone resin do. As the reactive cured silicone resin, an addition reaction system, a condensation reaction system, an ultraviolet ray or electron beam curing system, or the like can be used. More preferably, it is a low-temperature curable addition reaction system that can be processed at a low temperature, and an ultraviolet ray or electron beam curing system. By using such a thing, it can process at low temperature at the time of the coating process to a polyester film. Therefore, heat damage to the polyester film at the time of processing is small, a polyester film with high flatness is obtained, and defects such as pinholes can be reduced even at the time of producing a thin resin sheet.

As an addition reaction system silicone resin, what is made to react and harden the polydimethylsiloxane and hydrogensiloxane which introduced the vinyl group at the terminal or side chain using a platinum catalyst, for example is mentioned. At this time, it is more preferable to use a resin that can be cured at 120°C within 30 seconds because processing at low temperatures is possible. Examples include low-temperature addition curing types (LTC1006L, LTC1056L, LTC300B, LTC303E, LTC310, LTC314, LTC350G, LTC450A, LTC371G, LTC750A, LTC755, LTC760A, etc.) and thermal UV curing types (LTC851, BY24-510, BY24 -561, BY24-562, etc.), solvent-added + UV curing type manufactured by Shin-Etsu Chemical Co., Ltd. (X62-5040, X62-5065, X62-5072T, KS5508, etc.), dual cure curing type (X62-2835, X62-2834, X62- 1980, etc.) and the like.

Examples of the condensation-reacting silicone resin include a condensation reaction between polydimethylsiloxane having an OH group at the terminal and polydimethylsiloxane having an H group at the terminal using an organic tin catalyst to form a three-dimensional crosslinked structure. there is.

As the ultraviolet curable silicone resin, for example, as the most basic type, one using a radical reaction such as normal silicone rubber crosslinking, one that is photocured by introducing an unsaturated group, and one that decomposes an onium salt with ultraviolet rays to release a strong acid. crosslinking by cleavage of an epoxy group and crosslinking by addition reaction of thiol to vinylsiloxane. In addition, electron beams may be used instead of the ultraviolet rays. Electron beams have higher energy than ultraviolet rays, and it is possible to carry out a crosslinking reaction by radicals without using an initiator as in the case of ultraviolet curing. Examples of the resin used include UV curable silicones (X62-7028A/B, X62-7052, X62-7205, X62-7622, X62-7629, X62-7660, etc.) manufactured by Shin-Etsu Chemical Co., Ltd., Momentive Performance Material UV-curable silicones (TPR6502, TPR6501, TPR6500, UV9300, UV9315, XS56-A2982, UV9430, etc.) manufactured by Zusa, UV-curable silicones (silicolith UV POLY200, POLY215, POLY201, KF-UV265AM, etc.) manufactured by Arakawa Chemical Co., Ltd. can be heard

As the ultraviolet curable silicone resin, acrylate-modified or glycidoxy-modified polydimethylsiloxane or the like can also be used. Even when these modified polydimethylsiloxanes are mixed with a polyfunctional acrylate resin or an epoxy resin and used in the presence of an initiator, good release performance can be obtained.

Examples of other resins used include alkyd resins and acrylic resins subjected to stearyl modification, lauryl modification, or the like, or alkyd resins, acrylic resins, and olefin resins obtained by reaction of methylated melamine or the like.

As amino alkyd resin obtained by the reaction of the said methylated melamine, etc., Tespine 303 by Hitachi Chemical Co., Ltd., Tespine 305, Tespine 314, etc. are mentioned. As an aminoacrylic resin obtained by reaction of methylation melamine, etc., Tespine 322 by Hitachi Chemical Co., Ltd., etc. are mentioned.

When using the said resin for the release layer of this invention, you may use it by 1 type, and you may mix and use two or more types. Moreover, it is also possible to mix additives, such as a light peeling additive and a heavy peeling additive, in order to adjust peeling force.

You may add additives, such as an adhesion improver and an antistatic agent, etc. to the release layer of this invention. In addition, in order to improve adhesion to the substrate, it is also preferable to pre-treat the surface of the polyester film before providing the release layer with anchor coat, corona treatment, plasma treatment, or atmospheric plasma treatment.

In the present invention, the thickness of the release layer may be set according to the purpose of use, and is not particularly limited, but is preferably in the range of 0.005 to 2.0 µm in thickness of the release layer after curing. When the thickness of the release layer is 0.005 μm or more, the peeling performance is maintained, which is preferable. Moreover, when the thickness of the release layer is 2.0 μm or less, the curing time does not become too long, and there is no fear of causing unevenness in the thickness of the resin sheet due to a decrease in the flatness of the release film, which is preferable. In addition, since the curing time does not become too long, there is no fear of aggregation of the resin constituting the release coating layer, and there is no fear of forming protrusions, so pinhole defects in the resin sheet are less likely to occur, which is preferable.

It is preferable that the surface free energy of the release layer provided on the base film of this invention is 12 mJ/m<2> or more. More preferably, it is 18 mJ/m<2> or more, and 20 mJ/m<2> or more is still more preferable. If it is 12 mJ/m 2 or more, it is preferable because cissing or the like hardly occurs when the solution of the resin sheet is applied.

It is preferable that the surface free energy of the release layer provided on the base film of the present invention is 40 mJ/m 2 or less. More preferably, it is 35 mJ/m<2> or less, and 30 mJ/m<2> or less is still more preferable. If it is 40 mJ/m<2> or less, since the peelability of the molded resin sheet is good, it is preferable.

In the present invention, the surface free energy means the surface free energy of at least the surface of the release layer in contact with the resin sheet.

The water attachment energy of the surface of the release layer of the present invention in contact with the resin sheet is, for example, 3.0 mJ/m 2 or more, and preferably 3.5 mJ/m 2 or more. More preferably, it is 4.0 mJ/m<2> or more, and 5.5 mJ/m<2> or more is still more preferable. When it is 3.0 mJ/m<2> or more, when coating the solution of a resin sheet, since the rising of the coating end part is suppressed, it is preferable. When the swelling of the coated edge during coating is suppressed, the edge bulge at the time of winding the laminated film into a roll is suppressed, and the winding state becomes good, so the flatness of the laminated film becomes good, so it is preferable.

In order to improve the water attachment energy on the surface of the release layer, it can be achieved by adding an additive to the release layer or adjusting the polymer composition. For example, in the case of a silicone resin, it can be improved by introducing a siloxane unit having a phenyl group in the side chain into the polydimethylsiloxane skeleton, or adding a T unit (trifunctional) or Q unit (tetrafunctional) silicone resin or the like.

In order to improve the water attachment energy on the surface of the release layer, it is also possible to change the composition of the silicone resin as a method other than the above. For example, an addition reaction system silicone resin can be cured by heating polydimethylsiloxane and hydrogensiloxane in which a vinyl group is introduced into the terminal or side chain under a platinum catalyst, and the molar amount of the vinyl group (Si-Vy) at the terminal On the other hand, the water attachment energy can be changed by changing the molar amount of the Si-H groups of the hydrogensiloxane. For example, with respect to Si-Vy, the more Si-H tends to increase the water attachment energy, and the Si-H/Si-Vi ratio is preferably 1.0 or more, more preferably 1.5 or more, and 2.0 or more. more preferable

It is preferable that the release layer of the present invention has an arithmetic mean height (Sa) of not only the polyester base material but also the release layer of 20 nm or less. Moreover, as for arithmetic mean height Sa, it is especially preferable that it is 10 nm or less. If Sa is 20 nm or less, occurrence of pinholes, local thickness unevenness, etc., hardly occurs during molding of the resin sheet, which is preferable. Although it can be said that the arithmetic mean height Sa of the release layer is preferably smaller, it may be 0.1 nm or more.

Further, the maximum protrusion height (P) of the release layer is, for example, 500 nm or less, preferably 200 nm or less, more preferably 150 nm or less, still more preferably 100 nm or less, for example, 85 nm or less, and 50 nm or less. particularly preferred. When the maximum protrusion height P is 500 nm or less, defects such as pinholes and local thinning do not occur during formation of the resin sheet, and the yield is good, which is preferable.

In the present invention, the method for forming the release layer is not particularly limited, and a coating solution obtained by dissolving or dispersing a resin having release properties is spread on one side of a polyester film as a base material by application or the like, and a solvent or the like is dried. After removal, a method of heat drying, heat curing or ultraviolet curing is used.

As the coating method of the release layer, any known coating method can be applied. For example, a roll coating method such as a gravure coating method or a reverse coating method, a bar coating method such as a wire bar, a die coating method, and a spray Conventionally known methods such as a coating method and an air knife coating method can be used.

When a thermosetting material is used for the release layer, the drying temperature during solvent drying and thermal curing is preferably 180°C or less, more preferably 160°C or less, still more preferably 140°C or less, and 120°C or less. most desirable The heating time is preferably 30 seconds or less, more preferably 20 seconds or less, and most preferably 10 seconds or less. In the case of 180°C or less, the planarity of the film is maintained, and there is little possibility of causing unevenness in the thickness of the resin sheet, which is preferable. If it is 120 degrees C or less, it can process without impairing the planarity of a film, and since the possibility of causing thickness nonuniformity of a resin sheet further reduces, it is especially preferable.

The lower limit of the drying temperature is not particularly limited, but is preferably 60°C or higher. It is preferable because a release film can be obtained without the solvent remaining in the release layer at 60°C or higher.

When an ultraviolet curable material is used for the release layer, the drying temperature during solvent drying and heat curing is preferably 120°C or less, more preferably 100°C or less, and most preferably 90°C or less. The heating time is preferably 30 seconds or less, more preferably 20 seconds or less, and most preferably 10 seconds or less. In the case of 120°C or less, the planarity of the film is maintained, and there is little possibility of causing unevenness in the thickness of the resin sheet, which is preferable. If it is 90 degrees C or less, it can process without impairing the planarity of a film, and since the possibility of causing thickness nonuniformity of a resin sheet further reduces, it is especially preferable.

The lower limit of the drying temperature is not particularly limited, but is preferably 60°C or higher. It is preferable because a release film can be obtained without the solvent remaining in the release layer at 60°C or higher.

When using an ultraviolet-curable material for a release layer, it is preferable to irradiate an active energy ray and make a hardening reaction after drying the above-mentioned solvent. As active energy rays to be used, known techniques such as ultraviolet rays and electron beams can be used, and it is preferable to use ultraviolet rays. The cumulative amount of light when ultraviolet rays are used can be expressed as the product of the illuminance and the irradiation time. For example, it is preferable that it is 10-500 mJ/cm<2>. By setting it as more than the said lower limit, since a release layer can fully be hardened, it is preferable. By using below the said upper limit, since the thermal damage to the film by the heat|fever at the time of irradiation can be suppressed and the smoothness of the surface of a release layer can be maintained, it is preferable.

(resin sheet)

The laminated film of this invention has a resin sheet arrange|positioned on the surface on the opposite side to the base material in a release layer.

For example, the resin sheet laminated on the release film of the present invention is obtained by curing a resin sheet forming composition containing at least a resin component (A) and a crosslinking agent (B).

As a result of intensive studies, the resin sheet of the present invention is cured in a state in which the resin component (A) and the crosslinking agent (B) are phase separated by preparing under the specific conditions described later, for example, from the resin sheet forming composition according to the present invention. It is possible to do this, and appropriate unevenness can be formed on the surface of the resin sheet, so that the resin sheet can exhibit slipperiness without containing particles or the like.

The combined mass ratio of the resin component (A) and the crosslinking agent (B) is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more of the total solid content of the resin sheet. When 80% by mass or more is contained, physical properties such as strength and heat resistance of the resin sheet are improved, so it is preferable.

As for the mass ratio of a resin component (A) and a crosslinking agent (B), (A)/(B)=90/10 - 50/50 are preferable. When the blending ratio of the crosslinking agent (B) is 10% by mass or more, unevenness after phase separation tends to increase and slipperiness improves, so it is preferable. When the blending ratio of the crosslinking agent (B) is 50% by mass or less, it is preferable because the film strength of the resin sheet does not decrease and the handling property as a sheet is excellent. can also be prevented. For example, it is preferable that the ratio of the crosslinking agent (B) contained in the resin sheet to the entire resin sheet is 10% by mass or more and 50% by mass or less. In one aspect, the ratio of the crosslinking agent (B) contained in the resin sheet to the entire resin sheet is 10% by mass or more and less than 50% by mass, for example, 15% by mass or more and 45% by mass or less. By including the crosslinking agent (B) under such conditions, the above effect can be achieved more satisfactorily.

The resin component (A) is not particularly limited, and known resins can be used. For example, epoxy-based resins, phenoxy-based resins, polyester-based resins, urethane-based resins, fluorine-based resins, acrylic resins, olefin-based resins, imide-based resins, sulfone-based resins, etc. can be used. You may mix and use the above. The weight average molecular weight (Mw) of the resin component (A) used in the present invention is 10000 or more, preferably 10000 or more and 200000 or less, more preferably 30000 or more and 100000 or less. When it is 10000 or more, the strength of the resin sheet is strong and the handleability is good, so it is preferable. If it is 200000 or less, since the viscosity of a solution will become low and productivity will be favorable when forming a solution into a film, it is preferable. Although the method of measuring the weight average molecular weight (Mw) is not particularly limited, it can be measured using GPC or the like.

The crosslinking agent (B) is not particularly limited, and a known crosslinking agent can be used. For example, crosslinking agents such as isocyanate, melamine, carbodiimide, and oxazoline can be used, and either one type or a mixture of two or more types may be used. It is preferable that it reacts with the functional group contained in the resin component (A). It is preferable that the crosslinking agent (B) contained in the resin sheet forming composition is a liquid under the condition of 30 degreeC. In the present invention, the liquid may have fluidity, and may have, for example, a viscosity of 10000 mPa·s or less. By being a liquid at 30°C, phase separation from the resin component (A) can be effectively promoted during drying of the solution film formation of the resin sheet, and irregularities on the surface of the resin sheet tend to occur, which is preferable.

The resin sheet may contain additives other than the resin component (A) and the crosslinking agent (B) as long as the above ranges are satisfied. However, the resin sheet does not contain particles substantially. Since the resin sheet according to the present invention does not substantially contain particles, for example, in the case of optical applications, the transparency of the molded resin sheet is increased, and the electrical properties are improved in electronic parts such as dielectric sheets used for film capacitors. It is preferable because such effects are easy to be obtained. For example, if it is an optical use, the resin sheet may have a haze of 2% or less. Moreover, the haze may be 1% or less. 1 aspect WHEREIN: The haze of a resin sheet is 0.1 % or more. Moreover, for example, if it is an electronic component, such as a film capacitor, the resin sheet may have a dielectric breakdown voltage of 200 V/micrometer or more. Further, the dielectric breakdown voltage may be 300 V/μm or more. In one aspect, the dielectric breakdown voltage is 500V/μm or less.

Even if the resin sheet of the present invention does not substantially contain particles, it can have good slipperiness because the surface has minute irregularities resulting from the phase separation of the resin component (A) and the crosslinking agent (B). there is. The static friction coefficient of the resin sheet peeled from the base film is preferably 1.5 or less, more preferably 1.0 or less, and still more preferably 0.8 or less. As a resin sheet having a static friction coefficient of 1.5 or less, when used for optical applications or electronic parts applications, it is preferable because it has good winding properties, running properties, and the like and facilitates handling. The static friction coefficient of the resin sheet may be 0.1 or more.

In one embodiment, the coefficient of static friction measured by overlapping the surface 1 of the resin sheet on the opposite side to the release layer of the resin sheet indicated by reference numeral 13 in FIG. 2 and the surface 2 of the resin sheet indicated by reference numeral 14 is , less than 1.5. The static friction coefficient measured under the above conditions is more preferably 1.0 or less, and more preferably 0.8 or less. Moreover, the static friction coefficient may be 0.1 or more.

Thus, when the coefficient of static friction measured by overlapping both surfaces of the resin sheet is within the above range, the resin sheet of the present invention can achieve both high smoothness, excellent windability and runability.

The arithmetic mean roughness (Sa) of the surface (1) of the resin sheet of the laminated film of the present invention (surface opposite to the surface in contact with the release layer) is 2 nm or more and 30 nm or less, more preferably 2 nm or more and 20 nm or less, and 2.5 nm or more and 15 nm or less are more preferable. When it is 2 nm or more, the slipperiness of the resin sheet becomes good, which is preferable. If it is 30 nm or less, even when the resin sheet is peeled from the laminated film and only the resin sheet is wound up in a roll shape, the risk of occurrence of defects such as pinholes is reduced, which is preferable.

The maximum cross-sectional height (St) of the surface (1) of the resin sheet of the laminated film of the present invention (surface opposite to the surface in contact with the release layer) is 80 nm or more and 1000 nm or less, more preferably 100 nm or more and 600 nm or less, and 150 nm More than 500 nm or less is more preferable. When it is 80 nm or more, the slipperiness of the resin sheet becomes good, which is preferable. If it is 1000 nm or less, even when the resin sheet is peeled from the laminated film and only the resin sheet is wound in a roll shape, the risk of occurrence of defects such as pinholes is reduced, which is preferable.

Further, the maximum cross-sectional height (St) is a value obtained by adding the absolute values of the maximum projection height (P) and the maximum valley depth (V).

The maximum projection height (P) of the surface (1) of the resin sheet of the laminated film of the present invention (surface opposite to the surface in contact with the release layer) is preferably 500 nm or less, more preferably 250 nm or less, and even more preferably 200 nm or less. It is preferably 185 nm or less, for example, 150 nm or less, and particularly preferably 135 nm or less. For example, 100 nm or less may be sufficient.

If the maximum protrusion height P is 500 nm or less, even when the resin sheet is peeled from the laminated film and only the resin sheet is wound up in a roll shape, there is no generation of defects such as pinholes, which is preferable. The maximum protrusion height P can be said to be as preferable as it is smaller, but may be 1 nm or more, may be 3 nm or more, and may be, for example, 35 nm or more.

By making the arithmetic mean roughness (Sa) and the maximum section height (St) of the surface (1) of the resin sheet of the laminated film of the present invention within the above ranges, even a surface with high smoothness can obtain good slipperiness. In particular, it is preferable to control the maximum sectional height St within the above range.

In one aspect, the maximum valley depth (V) of the surface 1 of the resin sheet of the laminated film is preferably 45 nm or more and 350 nm or less, for example, 45 nm or more and 300 nm or less, and preferably 45 nm or more and 250 nm or less. When the maximum valley depth V is within this range, even if the maximum protrusion height P is in the range of 250 nm or less, it becomes easy to control the maximum cross-sectional height St within the above range, and the slipperiness of the resin sheet is improved. It is desirable because it can be done.

The arithmetic average roughness (Sa) of the surface (2) (surface in contact with the release layer) of the resin sheet of the laminated film of the present invention is preferably 10 nm or less, more preferably 8 nm or less, and still more preferably 5 nm or less. If it is 10 nm or less, even when the resin sheet is peeled from the laminated film and only the resin sheet is wound up in a roll shape, the risk of occurrence of defects such as pinholes is reduced, which is preferable.

The film thickness (t1) of the resin sheet of this invention is 1 micrometer or more and 20 micrometers or less. More preferably, they are 1 μm or more and 10 μm or less, and still more preferably 2 μm or more and 8 μm or less. If the film thickness (t1) of a resin sheet is 1 micrometer or more, it is hard to tear even after peeling from a base film, and since it can handle easily, it is preferable. When the film thickness (t1) of the resin sheet is 20 μm or less, it is preferable because the thickness of the wet coating film does not become too thick during solution film formation and molding is easy.

The film thickness (t1) of the resin sheet is not particularly limited and can be measured by a known method. For example, a contact type film thickness meter, an optical interference type film thickness meter, or a cross section can be observed and measured with a scanning electron microscope or a transmission electron microscope.

As a method of laminating the resin sheet of the present invention on a base film, a coating solution containing at least the above-described resin component (A) and crosslinking agent (B) and dissolved or dispersed in an organic solvent or water is applied to the release layer by a solution film forming method. It is preferable to mold in, and it can be applied by a known method similar to the application method of the release layer. For example, a conventionally known method such as a roll coating method such as a gravure coating method or a reverse coating method, a bar coating method such as a wire bar, a die coating method, a spray coating method, or an air knife coating method can be used.

It is preferable to have a heating process to dry and harden the solvent after applying the coating solution to the release layer. Although the heating method is not specifically limited, The laminated film after application|coating can be heated using hot air, infrared rays, etc. It is preferable to apply and dry the laminated film of the present invention by roll to roll, and it is particularly preferable to dry using hot air in a drying furnace using a floating method or a roll support method.

The temperature during drying is preferably 60°C or more and 160°C or less, more preferably 70°C or more and 140°C or less, and still more preferably 70°C or more and 130°C or less. A temperature of 60° C. or higher is preferable because there is little residual solvent in the resin sheet after drying and there is no risk of deterioration in the performance of the resin sheet (for example, electrical properties in the case of a dielectric layer application). If it is 160 degrees C or less, since there is no possibility that wrinkles will arise in a laminated|multilayer film by heat, it is preferable. If the temperature is higher than 160°C, phase separation between the resin component and the crosslinking agent in the resin sheet may excessively proceed and the crosslinking density of the resin sheet may decrease. Therefore, the temperature is preferably 160°C or lower.

It is preferable that the time from applying the said coating liquid to a base film, and entering a drying oven is within 5 seconds, more preferably within 3 seconds, and still more preferably within 2 seconds. Within 5 seconds, the phase separation of the resin component and the crosslinking agent in the coating liquid does not proceed too much, and there is no fear that the crosslinking density of the resin sheet is reduced, which is preferable.

It is preferable that it is 1 second or more, and, as for the time to heat to the maximum temperature in a drying furnace after apply|coating the said coating liquid to a base film, it is preferable that it is 2 seconds or more. If it is 1 second or longer, the reaction of the crosslinking agent proceeds, which is preferable. The upper limit of the heating time is preferably within 60 seconds, more preferably within 40 seconds, and even more preferably within 20 seconds. If it is within 60 seconds, it is possible to suppress the excessive segregation of the crosslinking agent on the surface of the resin sheet and to prevent deterioration in the performance of the resin sheet, which is preferable.

By subjecting the resin sheet of the present invention to the above-described drying conditions, the phase separation of the resin component (A) and the crosslinking agent (B) is appropriately advanced, and the arithmetic average roughness (Sa) and maximum cross-sectional height (St ) can be controlled within the above range, and good slipperiness of the resin sheet can be expressed without adding particles to the resin sheet.

(laminated film)

In the laminated film of the present invention, the resin sheet is separated from the base film after the next step and used. Therefore, when the peeling force from the base film is 800 mN/25 mm width or less, the resin sheet can be peeled without breaking or the like, which is preferable. More preferably, it is 500 mN/25 mm width or less, still more preferably 300 mN/25 mm width or less, still more preferably 200 mN/25 mm width or less. Since the peeling force varies depending on the resin sheet to be laminated, it can be adjusted according to the type of the mold release layer of the base film.

Example

Next, the present invention will be described in detail using examples and comparative examples, but the present invention is not necessarily limited to the following examples. In addition, the evaluation method used in this invention is as follows.

(arithmetic mean height (Sa), maximum asperity height (P), maximum valley depth (V), maximum section height (St))

It is a value measured under the following conditions using a non-contact surface shape measuring system (VertScan R550H-M100, manufactured by Ryoka Systems Co., Ltd.). The arithmetic mean height (Sa) adopted the average value of 5 measurements, and the maximum protrusion height (P) and maximum valley depth (V) were measured 7 times, and the maximum value of 5 times excluding the maximum and minimum values was used. As the maximum cross-sectional height (St), a value obtained by adding the absolute values of the maximum protrusion height (P) and the maximum valley depth (V) was adopted.

(Measuring conditions)

・Measurement mode: WAVE mode

・Objective lens: 10x

・0.5×Tube lens

・Measurement area 936㎛×702㎛

(analysis condition)

Face correction: 4th correction

・Interpolation processing: complete interpolation

・Filter treatment: Gaussian cutoff value 50㎛

(surface free energy)

Water (droplet amount: 1.8 μL) and diiodomethane were applied to the release surface of the release film using a contact angle meter (manufactured by Kyowa Science and Technology Co., Ltd.: Fully automatic contact angle meter DM-701) under conditions of 25°C and 50% RH. (droplet amount: 0.9 μL) was created and the contact angle was measured. As the contact angle, the contact angle after 10 seconds after dropping each liquid onto the release film was employed. Calculate the contact angle data of water and diiodomethane obtained by the above method according to the "Owens and Wendt" theory to determine the dispersion component γd of the surface free energy of the release film and the component γh based on hydrogen bonding and dipole-dipole interaction, The total sum of each component was taken as the surface free energy γs. This calculation was performed using analysis software in this contact angle meter software (FAMAS).

(water attachment energy)

Under conditions of 25°C and 50% RH, water (droplet amount: 10 µL) was dropped onto the release surface of the release film using a contact angle meter (manufactured by Kyowa Science and Technology Co., Ltd.: DM-701 fully automatic contact angle meter), and the dropwise addition After 2 seconds, the stage was tilted continuously and the contact angle was measured at every 1°. In addition, the inclination angle when moving 5 dots from the droplet position of 0° was determined as the sliding angle, and adhesion energy was calculated therefrom. This calculation was performed using analysis software in this contact angle meter software (FAMAS).

(film thickness)

The cut laminated film was resin-embedded and ultra-thin sectioned using an ultramicrotome. Thereafter, using a JEM2100 transmission electron microscope manufactured by JEOL Corporation, direct observation was performed at a magnification of 20,000, and the film thickness of each layer of the laminated film was measured from the observed TEM image.

(peel force)

The laminated film is cut into a strip shape with a width of 25 mm and a length of 150 mm, one end of the base film is fixed, one end of the resin sheet is supported, and the resin sheet side is pulled at a speed of 300 mm/min to form a T shape. Peel strength was measured. For the measurement, a tensile tester (“AUTOGRAPH AG-X” manufactured by Shimadzu Corporation) was used. As the measured value, the average value of 5 measurements was adopted.

Peelability was evaluated based on the following criteria from the measured peeling force.

○: Peeling was possible with a low peeling force of 100 mN/25 mm width or less, and peeling was possible without tearing even if it was a thin film.

○Δ: Peeling was possible with a peel force greater than 300 mN/25 mm width or less and 100 mN/25 mm width.

(triangle|delta): The peel force was greater than 300 mN/25 mm width, and it was able to peel at 800 mN/25 mm width or less. In areas where the film thickness is extremely thin, some tearing occurred.

x: It was not possible to peel.

(Static friction coefficient and slippery evaluation)

The static friction coefficient of the resin sheet was measured as follows, and slipperiness was evaluated.

The resin sheet was peeled off from the laminated film and fixed to the bottom of a metal rectangular parallelepiped weighing 1.4 kg so that the surface 2 of the resin sheet was facing the outside. Next, it was fixed with an adhesive tape on a flat metal plate so that the surface 1 of the resin sheet was turned outside. The metallic cuboid was placed so that the surface (1) and the surface (2) were in contact, and the static friction coefficient was measured at a tensile speed of 200 mm/min under the conditions of 23°C and 65% RH.

Slipperiness was judged according to the following criteria.

○: 0.1<μs≤0.8

△: 0.8 < μs ≤ 1.5

×: Exceeding 1.5 or measurement impossible because the friction coefficient is too high

(electrical characteristics)

A thin aluminum vapor deposition layer was provided 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 at the time of 10-point measurement was used and evaluated according to the following criteria.

○: Dielectric breakdown voltage (BDV value) of 300 V/μm or more

△: dielectric breakdown voltage of 200 V/μm or more

×: Dielectric breakdown voltage is less than 200 V/μm

(Preparation of polyethylene terephthalate pellets (PET(I)))

As the esterification reaction apparatus, a continuous esterification reaction apparatus consisting of a three-stage complete mixing tank having a stirrer, a condenser, a raw material inlet, and a product outlet was used. TPA (terephthalic acid) was 2 tons/hour, EG (ethylene glycol) was 2 moles per 1 mole of TPA, and antimony trioxide was used in an amount such that the Sb atom was 160 ppm with respect to the resulting PET, and these slurries were prepared It was continuously supplied to the first esterification reaction tube of the esterification reaction device and reacted at 255°C with an average residence time of 4 hours under normal pressure. Then, the reaction product in the first esterification reaction tube is continuously taken out of the system, supplied to the second esterification reaction tube, and distilled off from the first esterification reaction tube in the second esterification reaction tube. An EG solution containing magnesium acetate tetrahydrate in an amount such that 8% by mass of EG to be produced is supplied to product PET, and an amount of Mg atoms is 65 ppm with respect to product PET, and product PET EG solution containing TMPA (trimethyl phosphate) in an amount such that the number of P atoms is 40 ppm was added, and the mixture was reacted at 260° C. with an average residence time of 1 hour under normal pressure. Then, the reaction product in the second esterification reaction tube was continuously taken out of the system, supplied to the third esterification reaction tube, and averaged at a pressure of 39 MPa (400 kg/cm 2 ) using a high-pressure disperser (manufactured by Nippon Seiki Co., Ltd.) 0.2 mass% of porous colloidal silica having an average particle size of 0.9 μm subjected to dispersion treatment for 5 passes, and 0.4 mass% of synthetic calcium carbonate having an average particle size of 0.6 μm in which 1 mass% of an ammonium salt of polyacrylic acid is adhered per calcium carbonate, Each was added as a 10% EG slurry and reacted at 260°C with an average residence time of 0.5 hours at normal pressure. The esterification reaction product generated in the third esterification reaction tube is continuously supplied to a three-stage continuous polycondensation reactor to perform polycondensation, and 95% is filtered through a filter made of sintered stainless steel fibers with a cut diameter of 20 μm. After performing, ultrafiltration was performed, extruded in water, and after cooling, cut into chips to obtain PET chips having an intrinsic viscosity of 0.60 dl/g (hereinafter abbreviated as PET(I)). The lubricant content in the PET chip was 0.6% by mass.

(Preparation of polyethylene terephthalate pellets (PET(II)))

On the other hand, in the manufacture of the above PET chip, a PET chip having an intrinsic viscosity of 0.62 dl/g containing no particles such as calcium carbonate and silica was obtained (hereinafter abbreviated as PET (II)).

(Preparation of polyethylene terephthalate pellets (PET(III)))

PET (I) was carried out in the same manner as in PET (I), except that the type and content of the particles of PET (I) were changed to 0.75 mass% of synthetic calcium carbonate having an average particle diameter of 0.9 µm in which 1 mass% of the ammonium salt of polyacrylic acid was adhered per calcium carbonate. A chip was obtained (hereinafter abbreviated as PET(III)). The lubricant content in the PET chip was 0.75% by mass.

(Manufacture of base film X1)

After drying, these PET chips were melted at 285°C, melted at 290°C by a separate melting extruder, and a filter obtained by sintering stainless steel fibers having a 95% cut diameter of 15 µm and a filter having a 95% cut diameter of 15 µm Filters in which stainless steel particles are sintered are subjected to two-stage filtration, joined in a feed block, and PET (I) is laminated to form surface layer B and PET (II) to form surface layer A, in a sheet form at a speed of 45 m/min. After extrusion (casting), electrostatic contact and cooling were carried out on a casting drum at 30° C. by an electrostatic contact method, to obtain an unstretched polyethylene terephthalate sheet having an intrinsic viscosity of 0.59 dl/g. The layer ratio was adjusted so that PET(I)/PET(II) = 60%/40% by calculating the discharge amount of each extruder. Next, after heating this unstretched sheet with an infrared heater, it was stretched 3.5 times in the machine direction at a roll temperature of 80°C by a difference in speed between the rolls. After that, it was guided to a tenter and stretched 4.2 times in the transverse direction at 140°C. Subsequently, heat treatment was performed at 210°C in a heat setting zone. Thereafter, a 2.3% relaxation treatment was performed at 170°C in the transverse direction to obtain a base film X1 of a biaxially stretched polyethylene terephthalate film having a thickness of 25 µm. Sa of the surface layer A of the obtained base film X1 was 2 nm, and Sa of the surface layer B was 29 nm.

(Manufacture of base film X2 having release layer)

On the surface layer A of the base film X1 obtained above, the following release coating liquid Y1 is coated by the reverse gravure coating method so that the wet film thickness is 5 μm, and dried and cured at 120 ° C. for 30 seconds in a hot air drying furnace Base film with release layer X2 got Sa on the surface of the release layer was 2 nm.

(release coating liquid Y1)

toluene 48 mass parts

methyl ethyl ketone 48 mass parts

Silicone Resin Composition (1)

(Heat curing type silicone porcelain, Si-H/Si-Vy = 3.0, solid content 30% by mass)

3 parts by mass

SRX212P Catalyst (Pt curing catalyst manufactured by Dow-Toray)

0.1 parts by mass

(Manufacture of base film X3 having release layer)

Without changing the layer configuration and stretching conditions similar to those of the base film X1, the thickness was adjusted by changing the casting speed to create a biaxially stretched polyethylene terephthalate film with a thickness of 12 µm, and a release layer similar to that of X2. By installing, base film X3 was obtained. Sa of the surface layer A of the obtained film X3 was 3 nm, and Sa of the surface layer B was 29 nm.

(Method for producing base film X4 having release layer)

As base film X4, what provided the release layer similar to X2 on the surface layer A of 25 micrometer-thick A4100 (Cosmo Shine (registered trademark), product made by Toyobo) was used. A4100 has a configuration in which particles are not substantially contained in the film, and a coating layer containing particles is provided by in-line coating only on the surface layer B side. Sa of the surface layer A of the base film X4 was 1 nm, and Sa of the surface layer B was 2 nm.

(Method for producing base film X5 having release layer)

As base film X5, what provided the release layer similar to X2 on surface layer A of 25 micrometer-thick E5101 (Toyobo ester (registered trademark) film, Toyobo company make) was used. E5101 has a structure in which particles are contained in the surface layers A and B of the film. Sa of the surface layer A of the base film X5 was 25 nm, and Sa of the surface layer B was 25 nm.

(Manufacturing method of base film X6 having release layer)

On the surface layer A of the base film X1, the release coating liquid Y2 described below was applied to a wet film thickness of 5 μm by the reverse gravure coating method, and dried and cured in a hot air drying furnace at 120° C. for 30 seconds to obtain a base film X6 with a release layer. Sa on the surface of the release layer was 2 nm.

(release coating liquid Y2)

toluene 48 mass parts

methyl ethyl ketone 48 mass parts

Silicone Resin Composition (2)

(Heat-curable silicone porcelain, Si-H/Si-Vy = 1.0, solid content 30% by mass)

3 parts by mass

SRX212P Catalyst (Pt curing catalyst manufactured by Dow-Toray)

0.1 parts by mass

(Manufacturing method of base film X7 having release layer)

On the surface layer A of the base film X1, the release coating liquid Y3 described below was applied to a wet film thickness of 5 μm by the reverse gravure coating method, and dried and cured in a hot air drying furnace at 120° C. for 30 seconds to obtain a base film with a release layer X7. Sa on the surface of the release layer was 2 nm.

(release coating liquid Y3)

toluene 48 mass parts

methyl ethyl ketone 48 mass parts

Silicone Resin Composition (3)

(Heat-curable silicone porcelain, Si-H/Si-Vy = 2.2, solid content 30% by mass)

3 parts by mass

SRX212P Catalyst (Pt curing catalyst manufactured by Dow-Toray)

0.1 parts by mass

(Example 1)

On the surface layer A of the base film X2, the reverse gravure coating method is used to coat the resin solution Z1 so that the film thickness of the resin sheet after drying is 3 μm, and dried at 120 ° C. for 10 seconds in a hot air drying furnace to form a resin sheet and form a laminated film (At this time, after coating, it took 2 seconds to enter the drying furnace). Details are shown in Table 1 and Table 2.

(Resin Solution Z1)

methyl ethyl ketone 41.3 parts by mass

tetrahydrofuran 22.5 parts by mass

PKHB solution (solid content 40% by mass) 30.6 parts by mass

(Phenoxy resin manufactured by Gabriel Phenoxies, Mw32000)

＊The solution was prepared by dissolving phenoxy resin in tetrahydrofuran.

Milionate MR-200 5.3 parts by mass

(Tosoh Corporation make, isocyanate crosslinking agent, viscosity 200 mPa·s, solid content 99% by mass)

BYK-370 0.4 parts by mass

(manufactured by Big Chemie Japan, silicone surfactant)

(Examples 2 to 3)

Except having changed the base film to what was described in Table 1, it carried out similarly to Example 1, and created the laminated|multilayer film.

(Example 4)

A laminated film was created in the same manner as in Example 1, except that the resin component (A) was changed to resin solution Z6 in which the weight average molecular weight (Mw) was changed to another one.

(Resin Solution Z6)

methyl ethyl ketone 41.3 parts by mass

tetrahydrofuran 22.5 parts by mass

PKHJ solution (solid content 40% by mass) 30.6 parts by mass

(Phenoxy resin manufactured by Gabriel Phenoxies, Mw57000)

＊The solution was prepared by dissolving phenoxy resin in tetrahydrofuran.

Milionate MR-200 5.3 parts by mass

(Tosoh Corporation make, isocyanate crosslinking agent, viscosity 200 mPa·s, solid content 99% by mass)

BYK-370 0.4 parts by mass

(manufactured by Big Chemie Japan, silicone surfactant)

(Example 5)

A laminated film was created in the same manner as in Example 1, except that the type of crosslinking agent was changed to Resin Solution Z2.

(Resin Solution Z2)

methyl ethyl ketone 41.3 parts by mass

tetrahydrofuran 22.5 parts by mass

PKHB solution (solid content 40% by mass) 30.6 parts by mass

(Phenoxy resin manufactured by Gabriel Phenoxies, Mw32000)

＊The solution was prepared by dissolving phenoxy resin in tetrahydrofuran.

Milionate MR-400 5.3 parts by mass

(Tosoh Corporation make, isocyanate crosslinking agent, viscosity 600 mPa·s, solid content 99% by mass)

BYK-370 0.4 parts by mass

(manufactured by Big Chemie Japan, silicone surfactant)

(Example 6)

In order to change the kind of crosslinking agent, except having changed to resin solution Z3, it carried out similarly to Example 1, and created the laminated|multilayer film.

(Resin Solution Z3)

methyl ethyl ketone 41.3 parts by mass

tetrahydrofuran 22.5 parts by mass

PKHB solution (solid content 40% by mass) 30.6 parts by mass

(Phenoxy resin manufactured by Gabriel Phenoxies, Mw32000)

＊The solution was prepared by dissolving phenoxy resin in tetrahydrofuran.

Milionate MTL 5.3 parts by mass

(Tosoh Corporation make, isocyanate crosslinking agent, viscosity 50 mPa·s, solid content 99% by mass)

BYK-370 0.4 parts by mass

(manufactured by Big Chemie Japan, silicone surfactant)

(Example 7)

In order to change the ratio of resin and crosslinking agent, except having changed to resin solution Z4, it carried out similarly to Example 1, and created the laminated|multilayer film.

(Resin Solution Z4)

methyl ethyl ketone 41.3 parts by mass

tetrahydrofuran 19.9 parts by mass

PKHB solution (solid content 40% by mass) 35.0 parts by mass

(Phenoxy resin manufactured by Gabriel Phenoxies, Mw32000)

＊The solution was prepared by dissolving phenoxy resin in tetrahydrofuran.

Milionate MR-200 3.5 parts by mass

(Tosoh Corporation make, isocyanate crosslinking agent, viscosity 200 mPa·s, solid content 99% by mass)

BYK-370 0.4 parts by mass

(manufactured by Big Chemie Japan, silicone surfactant)

(Example 8)

In order to change the ratio of resin and crosslinking agent, except having changed to resin solution Z5, it carried out similarly to Example 1, and created the laminated film.

(Resin Solution Z5)

methyl ethyl ketone 41.3 parts by mass

tetrahydrofuran 17.3 parts by mass

PKHB solution (solid content 40% by mass) 39.4 parts by mass

(Phenoxy resin manufactured by Gabriel Phenoxies, Mw32000)

＊The solution was prepared by dissolving phenoxy resin in tetrahydrofuran.

Milionate MR-200 1.8 parts by mass

(Tosoh Corporation make, isocyanate crosslinking agent, viscosity 200 mPa·s, solid content 99% by mass)

BYK-370 0.4 parts by mass

(manufactured by Big Chemie Japan, silicone surfactant)

(Examples 9 to 11)

Except having changed to the base film described in Table 1, it carried out similarly to Example 1, and created the laminated|multilayer film.

(Examples 12 to 13)

Except having changed the drying temperature of the resin sheet to the temperature described in Table 1, it carried out similarly to Example 1, and created the laminated film.

(Comparative Example 1)

A laminated film was created in the same manner as in Example 1, except that the base film was changed to X1 without a release layer.

(Comparative Example 2)

A laminated film was created in the same manner as in Example 1 except that the resin solution was changed to resin solution Z6 containing no crosslinking agent.

(Resin Solution Z6)

methyl ethyl ketone 41.3 parts by mass

tetrahydrofuran 14.7 Parts by mass

PKHB solution (solid content 40% by mass) 43.8 parts by mass

(Phenoxy resin manufactured by Gabriel Phenoxies, Mw32000)

＊The solution was prepared by dissolving phenoxy resin in tetrahydrofuran.

BYK-370 0.4 parts by mass

(manufactured by Big Chemie Japan, silicone surfactant)

(Comparative Example 3)

A laminated film was created in the same manner as in Example 1, except that the resin sheet was formed such that the maximum cross-sectional height (St) of the surface 1 of the resin sheet was 75 nm.

The base film used in each Example was used after aging at 40°C for 3 days after processing the release layer. Moreover, the obtained laminated|multilayer film was also evaluated after aging at 40 degreeC for 3 days.

The laminated sheet of the present invention obtained in the examples is a resin sheet capable of enhancing transparency and the like in optical applications, for example, and can provide a resin sheet exhibiting high smoothness. In addition, it is possible to achieve both high smoothness and high slipperiness, and, for example, it is possible to suppress the occurrence of scratches in a conveyance step or the like, and a decrease in yield can be avoided.

In addition, for example, in electronic component applications such as film capacitor applications, a resin sheet exhibiting high smoothness can be provided, and the resin sheet can improve electrical properties such as dielectric breakdown voltage. In addition, it is possible to achieve both high smoothness and high slipperiness, and, for example, when winding the dielectric resin sheet into a roll, misalignment of the winding, mixing of wrinkles, etc. can be suppressed, and good winding properties can be exhibited. For this reason, conveyance or the like is possible while maintaining excellent capacitor performance.

In addition, the resin sheet obtained in the present invention does not contain substantially particles, and it is possible to avoid insufficient transparency such as an increase in internal haze. In addition, the problem of non-uniformity in the amount of particles transferred to the resin sheet can be avoided, and good slipperiness can be exhibited.

On the other hand, since Comparative Example 1 did not have the mold release layer concerning this invention, the peelability of the resin sheet was extremely bad, and the resin sheet could not be evaluated. In Comparative Example 2, since the resin sheet forming composition did not contain a crosslinking agent, the slipperiness of the resin sheet was particularly poor.

In Comparative Example 3, since the maximum cross-sectional height (St) of the surface 1 of the resin sheet was out of the range of the present invention, the slipperiness of the resin sheet was particularly poor.

The present invention relates to a laminated film in which resin sheets are laminated. In particular, it relates to a laminated film in which resin sheets used for electronic parts and optical applications are laminated.

10: base film 11: release layer
12 Resin sheet 13 Resin sheet surface (1)
14: surface of resin sheet (2)

Claims (7)

A polyester base film, a release layer disposed on at least one side of the base film, and a resin sheet disposed on a surface opposite to the substrate in the release layer,
A laminated film satisfying the following (1) to (6):
(1) The resin sheet is obtained by curing a resin sheet forming composition containing at least a resin component (A) and a crosslinking agent (B),
(2) The resin sheet contains substantially no particles,
(3) The film thickness (t1) of the resin sheet is 1 μm or more and 20 μm or less,
(4) the arithmetic mean height (Sa) of the surface (1) of the resin sheet is 2 nm or more and 30 nm or less;
(5) The maximum cross-sectional height (St) of the surface (1) of the resin sheet is 80 nm or more and 1000 nm or less,
(6) The static friction coefficient measured by overlapping the surface 1 on the side opposite to the surface of the release layer in the resin sheet and the surface 2 on the side of the release layer in the resin sheet is 1.5 or less. According to claim 1,
A laminated film characterized in that the crosslinking agent (B) contained in the resin sheet forming composition is liquid at 30°C. According to claim 1 or 2,
A laminated film characterized in that the ratio of the crosslinking agent (B) contained in the resin sheet to the entire resin sheet is 10% by mass or more. According to any one of claims 1 to 3,
A laminated film characterized in that the weight average molecular weight of the resin component (A) contained in the resin sheet is 10000 or more. According to any one of claims 1 to 4,
A laminated film characterized in that the surface free energy of the surface of the release layer is 40 mJ/m 2 or less, and the adhesion energy is 3.5 mJ/m 2 or more. According to any one of claims 1 to 5,
The arithmetic mean height (Sa) of the release layer side surface of the base film is 20 nm or less, and the maximum protrusion height (P) is 500 nm or less, the laminated film characterized by the above-mentioned. A method for producing a laminated film according to any one of claims 1 to 6, characterized in that a resin sheet is coated and molded on a base film by a solution film forming method.