Release film and film laminate

Abstract

To provide a release film, which has excellent releasability at the time of peeling the release film, via an adhesive layer, from an optical member (adherend) and the like such as a member and the like constituting a display panel and which also has excellent antistaticity and, especially, rub resistance.SOLUTION: Provided is a release film having, on at least one surface of a substrate film, a release layer formed of a resin composition comprising the following component (A), component (B), and component (C). Component (A):one or more selected from a polymer (a1) obtained by doping a polymer formed of thiophene or a thiophene derivative with another anionic compound and a polymer (a2) obtained by self-doping a polymer formed of thiophene or a thiophene derivative with an anionic group possessed by the polymer. Component (B): a release agent. Component (C): fluororesin particles.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a release film and a film laminate. [Background technology]

[0002] Release films having a release layer on at least one side of a base film are used in various fields such as industrial materials, optical materials, electronic component materials, battery packaging materials, etc. For example, in the manufacturing process of display panels, etc., release films are used to protect the adhesive that bonds the panel constituent members.

[0003] As the base film for release films, polyethylene terephthalate (PET) films, which are representative polyester films, and in particular biaxially oriented PET films, are widely used due to their excellent transparency, mechanical strength, heat resistance, flexibility, and the like. Polyester films have a common problem with plastic films in that they easily generate static electricity and become charged up. At manufacturing and processing sites, peeling static electricity can occur when a release film is peeled off from an adherend such as an adhesive. Therefore, not only can static electricity cause problems such as adhesion or entrapment of foreign matter, but static electricity can also cause serious problems such as damage to nearby electronic elements, resulting in product defects. Therefore, static electricity countermeasures based on equipment in the manufacturing process alone are not necessarily sufficient, and antistatic treatment of the release film itself is desired.

[0004] In view of this, for example, Patent Documents 1 and 2 propose a release film having an antistatic layer and a release layer in this order on the surface of a base film, which is said to have excellent releasability and excellent antistatic properties. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-6079 A [Patent Document 2] JP 2014-151573 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the release films disclosed in Patent Documents 1 and 2 not only complicate the manufacturing process due to the increased number of layers to be laminated, but also tend to increase potential problems between layers, such as poor adhesion. On the other hand, when a release film having antistatic and releasable properties is formed as a single-layer coating on the surface of a base film, the antistatic performance may be reduced due to friction during the manufacturing and inspection processes.

[0007] The problem that the present invention aims to solve is to provide a release film that has excellent releasability when peeled off from an optical component (adherend) such as a component constituting a display panel via an adhesive layer, and that has excellent antistatic properties, particularly abrasion resistance. [Means for solving the problem]

[0008] In view of the above circumstances, the present inventors have conducted intensive research and found that the above problems can be easily solved by using a release film having a release layer having a specific composition, and have completed the present invention. That is, the present invention has the following aspects.

[0009] [1] A release film having a release layer formed on at least one surface of a base film from a resin composition containing the following components (A), (B) and (C): Component (A): (a1) one or more selected from a polymer in which a compound consisting of thiophene or a thiophene derivative is doped with another anionic compound, and (a2) a self-doped polymer having an anionic group in a compound consisting of thiophene or a thiophene derivative. Component (B): Release agent Component (C): Fluorine resin particles [2] The release film according to the above [1], wherein the release agent of the component (B) is at least one member selected from the group consisting of long-chain alkyl group-containing compounds and waxes. [3] The release film according to the above [1] or [2], wherein the fluororesin particles of the component (C) are one or more members selected from the group consisting of hexafluoropropylene-tetrafluoroethylene copolymers and polytetrafluoroethylene. [4] The release film according to any one of the above [1] to [3], wherein the average particle size of the fluororesin particles of the component (C) is 10 to 1000 nm. [5] The release film according to any one of the above [1] to [4], wherein the content of the fluororesin particles of the component (C) is 0.1 to 20 mass% as a ratio of the total non-volatile components in the resin composition. [6] The release film according to any one of the above [1] to [5], wherein the resin composition further contains a binder resin as a component (D). [7] The release film according to the above [6], wherein the binder resin of the component (D) is at least one selected from the group consisting of polyurethane resins, polyester resins and acrylic resins. [8] The release film according to any one of the above [1] to [7], wherein the resin composition further contains, as a component (E), one or more selected from glycerin, polyglycerin, an alkylene oxide adduct of the glycerin or the polyglycerin, a sugar alcohol, and a sugar alcohol condensate.

[0010] [9] The surface resistivity (R x ) and the surface resistivity (R Y ) and the ratio (R Y / R x ) is 4.0 or less.

[10] The release film according to any one of the above [1] to [9], wherein after an acrylic adhesive tape ("No. 31B" manufactured by Nitto Denko Corporation) is attached to the release layer and left at 23°C for 1 hour, the 180° peel strength measured under conditions of 23°C and a tensile speed of 300 mm / min is 200 mN / cm or less.

[11] The release film according to any one of the above [1] to

[10] , wherein the base film is a polyester film.

[12] A film laminate in which the release film according to any one of the above [1] to

[11] is attached to an optical member via an adhesive layer.

[13] The film laminate according to the above

[12] , wherein the optical component is a resin film or a glass substrate.

[14] The film laminate according to the above

[13] , wherein the resin film is selected from the group consisting of a polyester film, a polyimide film, and a cyclic polyolefin film.

[15] The film laminate according to

[13] or

[14] above, which is a laminate film having a functional layer provided on the surface of the resin film that contacts the adhesive layer.

[16] The film laminate described in

[15] above, wherein the functional layer is another release layer.

[17] The film laminate according to

[16] above, wherein the other release layer comprises a curable silicone resin.

[18] The film laminate according to any one of the above

[12] to

[17] , which has a total thickness of 200 μm or less. Effect of the Invention

[0011] According to the present invention, there is provided a release film which has excellent releasability when peeled off from an optical component (adherend) such as a component constituting a display panel via an adhesive layer, and which has excellent antistatic properties, particularly abrasion resistance, and has high industrial utility value. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an example of an embodiment of the present invention will be described in detail. However, the present invention is not limited to the embodiment examples described below, and can be arbitrarily modified and implemented without departing from the gist of the present invention. In addition, in this specification, the term "A to B" (where A and B are arbitrary numbers) regarding the description of numerical values means "A or more and B or less" (when A < B) or "A or less and B or more" (when A > B), and also includes the meaning of "preferably greater than A" or "preferably less than B" (when A < B)) or "preferably greater than B" or "preferably less than A" (when A > B). Also, when expressed as "A or more" or "B or less", it also includes the intention of "preferably greater than A" or "preferably less than B". In the present invention, a combination of preferred embodiments is a more preferred embodiment. In this specification, when the expression "(meth)acrylic acid" is used, it means one or both of "acrylic acid" and "methacrylic acid". Similarly, "(meth)acrylate" means one or both of "acrylate" and "methacrylate", and "(meth)acryloyl" means one or both of "acryloyl" and "methacryloyl".

[0013] <Release film> Hereinafter, each member will be described in more detail. First, each member constituting the release film will be described in further detail. [Base film] The base film constituting the release film is not particularly limited as long as it is in the form of a film. For example, it may be made of paper, resin, metal, etc. Among these, from the viewpoints of mechanical strength and flexibility, it is preferably made of resin.

[0014] Examples of the resin substrate film include resin films formed from polymers such as polyethylene, polypropylene, cycloolefin polymer (COP), polyester, polystyrene, acrylic resin, polycarbonate, polyurethane, triacetyl cellulose (TAC), polyvinyl chloride, polyethersulfone, polyamide, polyimide, polyamideimide, etc. Furthermore, as long as it is possible to form a film, it may be a mixture of these materials (polymer blend) or a composite of the structural units (copolymer).

[0015] Among the above-listed substrate films, polyester films are particularly preferred because they have excellent physical properties such as heat resistance, flatness, optical properties, and strength. The polyester film may have a single layer structure or a multi-layer structure. When the polyester film has a multi-layer structure, the polyester film may have a two-layer structure, a three-layer structure, or a four-layer structure or more without departing from the gist of the present invention, and the number of layers is not particularly limited. The polyester film may be a non-stretched film (sheet) or a stretched film. Of these, a uniaxially or biaxially stretched film is preferable. Of these, a biaxially stretched film is more preferable from the viewpoints of balance of mechanical properties, flatness, and thinning.

[0016] The polyester used as the raw material for the polyester film may be either a homopolyester or a copolymer polyester. In the case of a homopolyester, it is preferable that the homopolyester is obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of aromatic dicarboxylic acids include terephthalic acid, 2,6-naphthalenedicarboxylic acid, etc. Examples of aliphatic glycols include ethylene glycol, diethylene glycol, 1,4-cyclohexanedimethanol, etc. A representative polyester is polyethylene terephthalate, etc. On the other hand, examples of the dicarboxylic acid component of the copolymer polyester include one or more of isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid, and examples of the glycol component include one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexanedimethanol, and neopentyl glycol.

[0017] The polyester polymerization catalyst is not particularly limited, and any conventionally known compound can be used, such as titanium compounds, germanium compounds, antimony compounds, manganese compounds, aluminum compounds, magnesium compounds, and calcium compounds.

[0018] In order to suppress the amount of precipitation of oligomer components, the film may be produced using a polyester having a low content of oligomer components as the raw material. As a method for producing a polyester having a low content of oligomer components, various known methods can be used, such as a method of performing solid phase polymerization after the production of a polyester. The amount of precipitation of oligomer components may be suppressed by forming the polyester film into a three-layer or more layer structure and making the outermost layer of the polyester film from a polyester raw material having a low content of oligomer components. The polyester may also be obtained by carrying out the esterification or transesterification reaction, followed by melt polycondensation at a higher reaction temperature under reduced pressure.

[0019] It is also possible to incorporate an ultraviolet absorbing agent into the polyester film in order to improve the weather resistance of the film and prevent deterioration of the adherend (for example, optical members such as members constituting a display panel), etc. The ultraviolet absorbing agent is a compound that absorbs ultraviolet light and is not particularly limited as long as it can withstand the heat applied in the manufacturing process of the polyester film.

[0020] The ultraviolet absorbing agent includes organic ultraviolet absorbing agents and inorganic ultraviolet absorbing agents, and from the viewpoint of transparency, organic ultraviolet absorbing agents are preferred.The organic ultraviolet absorbing agent is not particularly limited, but for example, cyclic imino ester type, benzotriazole type, benzophenone type, etc. are included.From the viewpoint of durability, cyclic imino ester type and benzotriazole type are more preferred. It is also possible to use two or more types of ultraviolet absorbents in combination.

[0021] Particles may be blended into the polyester film for the main purpose of imparting easy slippage and preventing scratches during each process. The type of particles to be blended is not particularly limited as long as it is a particle capable of imparting easy slippage, and examples thereof include inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, and titanium oxide; and organic particles such as acrylic resin, styrene resin, urea resin, phenolic resin, epoxy resin, and benzoguanamine resin. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process may also be used.

[0022] The shape of the particles to be used is not particularly limited, and any of spherical, blocky, rod-like, flat, etc. may be used. There are also no particular limitations on the hardness, specific gravity, color, etc. Two or more types of these particles may be used in combination as necessary.

[0023] The average particle size of the particles used is usually 5 μm or less, preferably in the range of 0.01 to 3 μm. If it is 5 μm or less, the surface roughness of the film does not become too rough, which is preferable since it does not cause problems when various surface functional layers are formed in a later process. The average particle size can be determined by observing with a transmission electron microscope (TEM) to measure the particle sizes of 10 particles and averaging the measured values.

[0024] Furthermore, the content of particles in the polyester film is usually less than 5% by mass, preferably in the range of 0.0003 to 3% by mass. When no particles are contained or when the content of particles is small, the transparency of the polyester film is high, but the slippage may be insufficient. Therefore, it may be necessary to improve the slippage by including particles in the release layer. When the particle content is less than 5% by mass, the transparency of the polyester film can be sufficiently guaranteed. When particles are contained in the polyester film, for example, it is preferable to provide a surface layer and an intermediate layer and to contain the particles in the surface layer. In this case, it is more preferable to form a multi-layer structure having a particle-containing surface layer, an intermediate layer, and a particle-containing surface layer in this order.

[0025] The method of adding particles to the polyester film is not particularly limited, and any conventionally known method can be adopted. For example, in the case of a multi-layer polyester film, the particles can be added at any stage of the production of the polyester constituting each layer, but it is preferable to add the particles after the completion of the esterification or transesterification reaction.

[0026] In addition to the above-mentioned particles, conventionally known antioxidants, antistatic agents, heat stabilizers, lubricants, dyes, pigments, etc. may be added to the polyester film as necessary.

[0027] The thickness of the polyester film is not particularly limited as long as it is within a range that allows formation of a film, but is preferably in the range of 5 to 350 μm, more preferably 8 to 125 μm, still more preferably 10 to 100 μm, and particularly preferably 12 to 75 μm.

[0028] Next, a specific example of the production of a polyester film will be described, but the production is not limited to the following production example. For example, when producing a biaxially stretched film, a method is preferred in which the dried pellets of the polyester raw material described above are extruded as a molten sheet from a die using an extruder, and then cooled and solidified with a cooling roll to obtain an unstretched sheet. In this case, it is preferred to increase the adhesion between the sheet and the rotating cooling drum in order to improve the flatness of the sheet, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably used. Next, the obtained unstretched sheet is stretched in biaxial directions. In this case, the unstretched sheet is first stretched in one direction by a roll or tenter type stretching machine. The stretching temperature is usually 70 to 120°C, preferably 80 to 110°C, and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Next, the sheet is stretched in a direction perpendicular to the first-stage stretching direction, in which the stretching temperature is usually 70 to 170°C, and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. Then, the film is subsequently heat-treated under tension or relaxation of 30% or less at a temperature of 180 to 270°C to obtain a biaxially stretched film. In the above stretching, a method of stretching in one direction in two or more stages can be adopted. In that case, it is preferable to perform the stretching so that the final stretch ratios in both directions are within the above ranges.

[0029] A simultaneous biaxial stretching method can also be used to produce the polyester film. The simultaneous biaxial stretching method involves simultaneously stretching and orienting the unstretched sheet in the machine direction and the width direction under a temperature controlled condition usually at 70 to 120° C., preferably 80 to 110° C., and the stretching ratio is preferably 4 to 50 times, more preferably 7 to 35 times, and even more preferably 10 to 25 times in terms of area ratio. Then, the film is subsequently heat-treated under tension or under relaxation of 30% or less at a temperature of 170 to 250° C. to obtain a stretched and oriented film. Regarding the simultaneous biaxial stretching device employing the above-mentioned stretching method, a conventionally known stretching method such as a screw method, a pantograph method, or a linear drive method can be employed.

[0030] [Release layer] The release film of the present invention has a release layer formed on at least one surface of a base film from a resin composition containing the following components (A), (B) and (C). Component (A): (a1) one or more selected from a polymer in which a compound made of thiophene or a thiophene derivative is doped with another anionic compound and (a2) a self-doped polymer having an anionic group in a compound made of thiophene or a thiophene derivative. Component (B): Release agent Component (C): Fluorine resin particles

[0031] When producing a film with high transparency, i.e., low haze, the amount of particles that can be added to the base film is limited, so particles, especially silica particles, are often added to the coating layer in order to improve the handling and abrasion resistance of the film.On the other hand, in the resin composition that forms the release layer of the release film of the present invention, when silica particles are contained, the abrasion resistance of the formed release layer is rather reduced compared to when no silica particles are contained, but when fluororesin particles as the above-mentioned component (C) are contained, the abrasion resistance of the formed release layer is improved.The details of the reason for this are not clear, but it is thought that the self-lubricating property of the fluororesin particles contributes to this. In this specification, the term "abrasion resistance" refers to an evaluation based on the change in surface resistivity measured by the method described in the examples below.

[0032] (Component (A)) The component (A) used in the present invention is at least one selected from (a1) a polymer in which a compound made of thiophene or a thiophene derivative is doped with another anionic compound, and (a2) a self-doped polymer having an anionic group in a compound made of thiophene or a thiophene derivative. An example of the component (A) is one obtained by polymerizing a compound of the following formula (1) or (2) in the presence of a polyanion. The polymer (a1) and the polymer (a2) may be used in combination.

[0033] [ka]

[0034] In the above formula (1), R 1 and R 2 each independently represents a hydrogen atom or an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group having 1 to 20 carbon atoms.

[0035] [ka]

[0036] In the above formula (2), n represents an integer of 1 to 4.

[0037] Examples of polyanions used in polymerization include poly(meth)acrylic acid, polymaleic acid, polystyrene sulfonic acid, polyvinyl sulfonic acid, etc. As a method for producing such a polymer, for example, a method such as that shown in JP-A-7-90060 can be adopted.

[0038] In the present invention, the compound of the above formula (2) in which n is 2 and polystyrene sulfonic acid is used as the polyanion is preferably used.

[0039] When these polyanions are acidic, they may be partially or completely neutralized. The base used for neutralization is preferably ammonia, organic amines, or alkali metal hydroxides.

[0040] The content of component (A) in the resin composition is preferably 0.1 to 30 mass%, more preferably 0.5 to 20 mass%, and even more preferably 1 to 10 mass%, as a ratio of the total non-volatile components in the resin composition. When the content of component (A) is equal to or less than the upper limit, the strength and transparency of the release layer are good. On the other hand, when the content of component (A) is equal to or more than the lower limit, sufficient antistatic properties are obtained.

[0041] (Component (B)) The component (B) used in the present invention is a release agent. From the viewpoint of improving releasability, it is preferable to use one or more compounds selected from the group consisting of long-chain alkyl group-containing compounds and waxes as the component (B).

[0042] ((Long-chain alkyl group-containing compound)) The long-chain alkyl group-containing compound refers to a compound having a straight-chain or branched alkyl group having usually 6 or more carbon atoms, preferably 8 or more carbon atoms, and more preferably 12 or more carbon atoms. Examples of the alkyl group include a hexyl group, an octyl group, a decyl group, a lauryl group, an octadecyl group, and a behenyl group. Examples of compounds having a long-chain alkyl group include various long-chain alkyl group-containing polymer compounds, long-chain alkyl group-containing ester compounds, long-chain alkyl group-containing amide compounds, long-chain alkyl group-containing ether compounds, etc. Considering heat resistance and staining properties, a long-chain alkyl group-containing polymer compound is preferable, and from the viewpoint of effectively imparting releasability, a polymer compound having a long-chain alkyl group in the side chain is more preferable.

[0043] A polymer compound having a long-chain alkyl group in a side chain can be obtained by reacting a polymer having a reactive group with a compound having an alkyl group capable of reacting with the reactive group. Examples of the reactive group include hydroxyl group, amino group, carboxyl group, acid anhydride, etc. Examples of polymers having these reactive groups include polyvinyl alcohol, polyethyleneimine, polyethyleneamine, reactive group-containing polyester resin, reactive group-containing poly(meth)acrylic resin, etc. Among these, polyvinyl alcohol is preferable in consideration of releasability and ease of handling.

[0044] Examples of compounds having an alkyl group capable of reacting with the reactive group include long-chain alkyl group-containing isocyanates such as hexyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate, and behenyl isocyanate; long-chain alkyl group-containing acid chlorides such as hexanoyl chloride, octanoyl chloride, decanoyl chloride, lauroyl chloride, octadecanoyl chloride, and behenoyl chloride; long-chain alkyl group-containing amines; long-chain alkyl group-containing alcohols; etc. Among these, in consideration of releasability and ease of handling, long-chain alkyl group-containing isocyanates are preferred, and octadecyl isocyanate is particularly preferred.

[0045] Furthermore, polymeric compounds having a long-chain alkyl group in the side chain can also be obtained by polymerization of a long-chain alkyl (meth)acrylate or copolymerization of a long-chain alkyl (meth)acrylate with another vinyl group-containing monomer. Examples of long-chain alkyl (meth)acrylate include hexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, octadecyl (meth)acrylate, and behenyl (meth)acrylate.

[0046] ((wax)) Examples of waxes include natural waxes, synthetic waxes, and waxes made by combining these.

[0047] Natural waxes include vegetable waxes, animal waxes, mineral waxes, petroleum waxes, and the like. Examples of vegetable waxes include candelilla wax, carnauba wax, rice wax, wood wax, jojoba oil, etc. Examples of animal waxes include beeswax, lanolin, whale wax, etc. Examples of mineral waxes include montan wax, ozokerite, ceresin, etc. Examples of petroleum waxes include paraffin wax, microcrystalline wax, petrolatum, etc.

[0048] Examples of synthetic waxes include synthetic hydrocarbons, modified waxes, hydrogenated waxes, fatty acids, fatty acid amides, amines, imides, ester waxes, and ketones. Synthetic hydrocarbons include Fischer-Tropsch wax (Sazol wax), polyethylene wax, oxidized polyethylene wax, oxidized polypropylene wax, etc. Also included are low molecular weight polymers (number average molecular weight 500 to 20,000), specifically, polypropylene, ethylene-acrylic acid copolymer, polyethylene glycol, polypropylene glycol, block or graft bond of polyethylene glycol and polypropylene glycol, etc. Examples of modified waxes include montan wax derivatives, paraffin wax derivatives, microcrystalline wax derivatives, etc. The derivatives referred to here refer to compounds obtained by any of the following treatments: purification, oxidation, esterification, and saponification, or a combination thereof. Examples of hydrogenated waxes include hydrogenated castor oil and derivatives of hydrogenated castor oil.

[0049] Among these waxes, synthetic waxes are preferred from the viewpoints of excellent release performance and ease of availability, synthetic hydrocarbons are more preferred, and oxidized polyethylene wax and oxidized polypropylene wax are even more preferred.

[0050] The content of component (B) in the resin composition is preferably 1 to 80 mass%, more preferably 5 to 60 mass%, and even more preferably 10 to 50 mass%, as a ratio of the total non-volatile components in the resin composition. When the content of component (B) is equal to or less than the upper limit, the strength of the release layer is good. On the other hand, when the content of component (B) is equal to or more than the lower limit, the releasability of the release film of the present invention is good.

[0051] (Component (C)) The component (C) used in the present invention is fluororesin particles. The fluororesin particles refer to fluororesin that has a particulate form in a dispersion medium such as water or alcohol at 25°C. By including the fluororesin particles in the resin composition according to the present invention, not only is it possible to achieve both releasability and antistatic properties, but it is also possible to achieve particularly excellent abrasion resistance.

[0052] Examples of fluororesin particles include polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and hexafluoropropylene-tetrafluoroethylene copolymer (FEP). Among these, from the viewpoint of versatility, FEP and PTFE are preferred, and FEP is more preferred.

[0053] The average particle size of the fluororesin particles in the dispersion solvent, as determined by dynamic light scattering, is preferably 10 to 1000 nm, more preferably 20 to 500 nm, and even more preferably 50 to 300 nm. If the average particle size is within this range, good coating appearance and improved strength of the release layer can be expected. Such fluororesin particles can be commercially available products, such as "Neoflon FEP ND-110," "Polyflon PTFE D-210C," and "Neoflon PFA AD-2CRER," both manufactured by Daikin Industries, Ltd.

[0054] The average particle size of the fluororesin particles is preferably 0.1 to 10 times the thickness of the release layer, more preferably 0.3 to 5 times, and even more preferably 0.5 to 3 times. By having the average particle size in this range, the handleability of the release film is improved and the strength of the release layer is improved.

[0055] The content of component (C) in the resin composition is preferably 0.1 to 20 mass%, more preferably 0.3 to 10 mass%, and even more preferably 0.5 to 5 mass%, based on the total non-volatile components in the resin composition. When the content of component (C) is equal to or less than the upper limit, good coating appearance and improved strength of the release layer are obtained. On the other hand, when the content of component (C) is equal to or more than the lower limit, the handling property of the film is improved and the strength of the release layer is improved.

[0056] (Component (D)) The resin composition for forming the release layer according to the present invention preferably contains a binder resin as component (D). The binder resin is more preferably one or more resins selected from the group consisting of polyurethane resins, polyester resins, and acrylic resins. When the release layer contains one or more resins selected from the group consisting of polyurethane resins, polyester resins, and acrylic resins, the film-forming properties, transparency, peelability, and the like of the release layer are improved.

[0057] ((Polyurethane resin)) The urethane resin is a polymeric compound having a urethane bond in the molecule, and is preferably water-dispersible or water-soluble. In the present invention, they may be used alone or in combination of two or more kinds.

[0058] In order to impart water dispersibility or water solubility, it is common and preferable to introduce hydrophilic groups such as hydroxyl groups, carboxyl groups, sulfonic acid groups, sulfonyl groups, phosphoric acid groups, ether groups, etc., into the urethane resin. Among the hydrophilic groups, carboxyl groups and sulfonic acid groups are particularly preferable in terms of the physical properties of the release layer and the adhesion between the release layer and the base film.

[0059] One of the methods for producing urethane resin is by the reaction of a hydroxyl group-containing compound with an isocyanate. As the hydroxyl group-containing compound used as a raw material, polyol is preferably used, for example, polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, and acrylic polyols. These compounds may be used alone or in combination.

[0060] Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol.

[0061] Examples of polyester polyols include polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their acid anhydrides and polyhydric alcohols (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 2-methyl-1,3-propanediol, 1,6 ... 2-ethyl-2,4-pentanediol, 2-methyl-2-propyl-1,3-propanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexanediol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyldialkanolamines, lactonediols, etc.

[0062] Examples of polycarbonate-based polyols include polycarbonate diols obtained by dealcoholization reaction of polyhydric alcohols with dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, etc., such as poly(1,6-hexylene) carbonate and poly(3-methyl-1,5-pentylene) carbonate.

[0063] Of these, polyester polyols are preferred.

[0064] Examples of polyisocyanate compounds used to obtain urethane resins include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate; aliphatic diisocyanates having an aromatic ring such as α,α,α',α'-tetramethyl xylylene diisocyanate; aliphatic diisocyanates such as methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, and hexamethylene diisocyanate; and alicyclic diisocyanates such as cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and isopropylidenedicyclohexyl diisocyanate. These may be used alone or in combination.

[0065] A chain extender may be used when synthesizing the urethane resin. The chain extender is not particularly limited as long as it has two or more active groups that react with an isocyanate group, and generally, a chain extender having two hydroxyl groups or two amino groups can be mainly used.

[0066] Examples of chain extenders having two hydroxyl groups include glycols such as aliphatic glycols such as ethylene glycol, propylene glycol, and butanediol; aromatic glycols such as xylylene glycol and bishydroxyethoxybenzene; and ester glycols such as neopentyl glycol hydroxypivalate.

[0067] Examples of chain extenders having two amino groups include aromatic diamines such as tolylenediamine, xylylenediamine, and diphenylmethanediamine; aliphatic diamines such as ethylenediamine, propanediamine, hexanediamine, 2,2-dimethyl-1,3-propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine; and alicyclic diamines such as 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, 1,4-diaminocyclohexane, and 1,3-bisaminomethylcyclohexane.

[0068] ((Polyester resin)) The polyester resin may be composed of, as main components, for example, the following polyvalent carboxylic acids and polyvalent hydroxy compounds. That is, examples of polyvalent carboxylic acids that can be used include terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4'-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutaric acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid, trimellitic acid monopotassium salt, and ester-forming derivatives thereof. Examples of polyhydric hydroxy compounds include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, and potassium dimethylolpropionate. One or more of these compounds may be appropriately selected from each of them, and a polyester resin may be synthesized by a conventional polycondensation reaction.

[0069] In addition, a product obtained by copolymerizing sulfoisophthalic acid as a part of the polycarboxylic acid, introducing a sulfonic acid group into the polyester skeleton, and neutralizing it to make it hydrophilic is preferably used. The amount of copolymerization is usually 1 to 10 mol %, preferably 2 to 8 mol %, based on the total amount of polycarboxylic acid. By introducing an appropriate amount of sulfonic acid group, the water dispersion stability can be further improved.

[0070] ((Acrylic resin)) The acrylic resin is a polymer made of polymerizable monomers including acrylic and methacrylic monomers. These may be homopolymers or copolymers, or copolymers with polymerizable monomers other than acrylic and methacrylic monomers. Also included are copolymers of these polymers with other polymers (such as polyesters and polyurethanes). For example, block copolymers and graft copolymers. That is, the acrylic resin may be an acrylic-modified polyester resin or an acrylic-modified polyurethane resin. Alternatively, it also includes a polymer (or a mixture of polymers, as the case may be) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in a polyester solution or polyester dispersion. Similarly, it also includes a polymer (or a mixture of polymers, as the case may be) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in a polyurethane solution or polyurethane dispersion. Similarly, it also includes a polymer (or a mixture of polymers, as the case may be) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in another polymer solution or dispersion. In order to further improve the adhesion of the release layer to the base film, the release layer may contain a hydroxyl group or an amino group.

[0071] The polymerizable monomer having a carbon-carbon double bond is not particularly limited, but particularly representative compounds include, for example, various carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid, and salts thereof; various hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, monobutyl hydroxyfumarate, and monobutyl hydroxyitaconate; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate, and the like. Examples of such compounds include various alkyl (meth)acrylic acid esters such as acrylates; various nitrogen-containing compounds such as (meth)acrylamide, diacetone acrylamide, or (meth)acrylonitrile; nitrogen-containing compounds containing a hydroxyl group such as N-methylol (meth)acrylamide; various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, and vinyl toluene; various vinyl esters such as vinyl propionate; various silicon-containing polymerizable monomers such as γ-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane; phosphorus-containing vinyl monomers; various vinyl halides such as vinyl chloride and vinylidene chloride; and various conjugated dienes such as butadiene.

[0072] Among the above acrylic resins, polymers obtained by polymerizing polymerizable monomers including acrylic and methacrylic monomers are preferred, and it is more preferred that the polymerizable monomers include alkyl (meth)acrylic esters. In addition, the resin composition is preferably diluted with a solvent to prepare a coating liquid as described below, and the solvent preferably contains water as the main solvent (50 mass% or more). That is, when the coating liquid is made aqueous, from the viewpoint of facilitating dissolving or dispersing the component (D), the polymerizable monomer preferably has a hydrophilic group such as a hydroxyl group or a carboxyl group. Therefore, the acrylic resin is also preferably a polymer obtained by polymerizing a polymerizable monomer including an alkyl (meth)acrylic acid ester and a hydrophilic group-containing monomer such as a hydroxyl group-containing monomer or a carboxyl group-containing monomer. The acrylic resin may also be an emulsion polymer obtained by polymerizing a polymerizable monomer in the presence of a surfactant.

[0073] As the component (D), a polyurethane resin or a polyester resin is preferable, and a polyester resin is more preferable, and from the viewpoint of the strength of the release layer, a polyester having a naphthalene skeleton is further preferable.

[0074] When the resin composition further contains component (D), its content is preferably 1 to 60 mass%, more preferably 2 to 30 mass%, and even more preferably 2 to 10 mass%, as a ratio of the total non-volatile components in the resin composition. When the content of component (D) is equal to or less than the upper limit, the mold releasability and antistatic property are sufficient. On the other hand, when the content of component (D) is equal to or greater than the lower limit, the strength of the release layer is sufficient.

[0075] (Component (E)) In order to achieve both high antistatic properties and high transparency without impairing releasability, the resin composition forming the release layer of the present invention preferably contains, as component (E), one or more compounds selected from glycerin, polyglycerin, alkylene oxide adducts of the glycerin or polyglycerin, sugar alcohols, and sugar alcohol condensates.

[0076] ((Glycerin, polyglycerin, alkylene oxide adducts of the glycerin or polyglycerin)) For example, there may be mentioned one compound or a derivative thereof selected from (b1) glycerin or polyglycerin represented by the following formula (3) and (b2) an alkylene oxide adduct of the glycerin or polyglycerin (b1).

[0077] [ka]

[0078] In the above formula (3), n is preferably 2 to 10, and more preferably in the range of 2 to 6. Within this range, the durability of the release layer is further improved, and the antistatic properties are also good.

[0079] The alkylene oxide adduct to polyglycerin has a structure in which alkylene oxide is addition polymerized to the hydroxyl group of polyglycerin represented by the general formula (3).

[0080] Here, the structure of the alkylene oxide added to each hydroxyl group of the polyglycerin skeleton may be different, and it is sufficient that the alkylene oxide or its derivative is added to at least one hydroxyl group in the molecule, and it is not necessary that the alkylene oxide or its derivative is added to all hydroxyl groups.

[0081] The alkylene oxide added to polyglycerin is preferably ethylene oxide or propylene oxide. If the alkylene chain of the alkylene oxide is too long, the hydrophobicity becomes strong, the dispersibility in the coating liquid deteriorates, and the antistatic property and transparency of the release layer tend to deteriorate. From this viewpoint, ethylene oxide is more preferable. The number of additions is preferably in the range of 200 to 2,000, more preferably in the range of 250 to 1,000, and even more preferably in the range of 300 to 800, in terms of the number average molecular weight of the final compound.

[0082] The polyglycerol or the alkylene oxide adduct of the polyglycerol may be used alone or in combination of two or more kinds.

[0083] ((Sugar alcohol)) The sugar alcohol refers to a chain polyhydric alcohol obtained by reducing the carbonyl group of aldose or ketose, or a cyclic polyhydric alcohol such as cyclitol. Specific examples include chain sugar alcohols such as erythritol, threitol, and other C4 sugar alcohols obtained by reducing monosaccharides; ribitol, arabinitol, xylitol, and other C5 sugar alcohols; sorbitol, mannitol, iditol, talitol, galactitol, and other C6 sugar alcohols. In addition, cyclic sugar alcohols such as cyclitols such as inositol can be used. In addition, disaccharide alcohols such as maltitol, lactitol, and reduced isomaltulose obtained by reducing disaccharides can be used. In addition, when the sugar alcohol has stereoisomers, all of the stereoisomers are included. The sugar alcohol may be used alone or in combination of two or more kinds.

[0084] From the viewpoint of not inhibiting releasability and achieving both high antistatic properties and high transparency, the sugar alcohol is preferably a sugar alcohol having 4 to 12 carbon atoms, more preferably a sugar alcohol having 4 to 6 carbon atoms, and particularly preferably a sugar alcohol having 6 carbon atoms. Chain sugar alcohols are preferred. From the above viewpoint, it is preferred to use sorbitol among the sugar alcohols.

[0085] ((Sugar alcohol condensation product)) The sugar alcohol condensate is a compound formed by intramolecular and / or intermolecular dehydration condensation of hydroxyl groups of sugar alcohols, and examples of such compounds include sorbitan and isosorbide.

[0086] When the resin composition further contains component (E), the content thereof is preferably 10 to 95 mass%, more preferably 20 to 90 mass%, and even more preferably 30 to 80 mass%, as a ratio of the total non-volatile components in the resin composition. When the content of component (E) is equal to or less than the upper limit, the water resistance of the release layer is sufficient. On the other hand, when the content of component (E) is equal to or greater than the lower limit, a release layer having sufficient conductivity, transparency and film-forming properties and a uniform release layer can be obtained.

[0087] (Component (F)) The resin composition for forming the release layer according to the present invention may contain a crosslinking agent as component (F) for the purpose of improving the durability of the release layer. As the crosslinking agent, various known crosslinking agents can be used, for example, melamine compounds, epoxy compounds, carbodiimide compounds, oxazoline compounds, isocyanate compounds, silane coupling compounds, etc. are listed. Among these, melamine compounds, epoxy compounds, isocyanate compounds, and carbodiimide compounds are preferred from the viewpoint of suppressing the decrease in antistatic properties after exposure to air, and melamine compounds and epoxy compounds are more preferred from the viewpoint of the strength of the release layer. These may be used alone or in combination of two or more kinds.

[0088] ((Melamine Compounds)) The melamine compound is a compound having a melamine skeleton in the compound, and for example, an alkylolated melamine derivative, a compound partially or completely etherified by reacting an alkylolated melamine derivative with an alcohol, and a mixture thereof can be used. As the alcohol used for etherification, methanol, ethanol, isopropanol, n-butanol, isobutanol, etc. can be suitably used. The melamine compound may be either a monomer or a dimer or higher polymer, or a mixture of these. Furthermore, melamine may be partially co-condensed with urea or the like, and a catalyst may be used to increase the reactivity of the melamine compound.

[0089] ((Epoxy Compounds)) The epoxy compound is a compound having an epoxy group in the molecule, and examples thereof include condensations of epichlorohydrin, ethylene glycol, polyethylene glycol, glycerin, polyglycerin, bisphenol A, etc. with a hydroxyl group or an amino group, polyepoxy compounds, diepoxy compounds, monoepoxy compounds, and glycidylamine compounds. Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris(2-hydroxyethyl)isocyanate, glycerol polyglycidyl ether, and trimethylolpropane polyglycidyl ether. Examples of diepoxy compounds include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcinol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and polytetramethylene glycol diglycidyl ether. Examples of the monoepoxy compound include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, and phenyl glycidyl ether, and examples of the glycidylamine compound include N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylamino)cyclohexane, etc. From the viewpoint of improving the adhesion of the release layer to the base film, polyether-based epoxy compounds are preferred. In terms of the amount of epoxy groups, a polyepoxy compound having three or more functional groups is more preferable than a polyfunctional compound having two functional groups.

[0090] ((Carbodiimide compound)) A carbodiimide compound is a compound having a carbodiimide structure, i.e., a compound having one or more carbodiimide structures in its molecule. However, for better adhesion between the release layer and the base film, a polycarbodiimide compound having two or more carbodiimide structures in its molecule is more preferred.

[0091] Carbodiimide compounds can be synthesized by conventionally known techniques, and generally, condensation reaction of diisocyanate compounds is used. The diisocyanate compounds are not particularly limited, and both aromatic and aliphatic compounds can be used, and specific examples include tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate, and dicyclohexylmethane 4,4'-diisocyanate.

[0092] The content of the carbodiimide group contained in the carbodiimide compound, in terms of carbodiimide equivalent (weight [g] of the carbodiimide compound for providing 1 mol of the carbodiimide group), is usually in the range of 100 to 1000, preferably 250 to 800, and more preferably 300 to 700. By using it in the above range, the durability of the release layer is improved.

[0093] Furthermore, within the scope of the present invention, in order to improve the water solubility or water dispersibility of the polycarbodiimide compound, a surfactant may be added, or a hydrophilic monomer such as a polyalkylene oxide, a quaternary ammonium salt of a dialkylamino alcohol, or a hydroxyalkylsulfonate may be added.

[0094] ((Oxazoline Compounds)) The oxazoline compound is a compound having an oxazoline group in the molecule, and in particular, a polymer containing an oxazoline group is preferred, and can be synthesized by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with other monomers. Examples of the addition polymerizable oxazoline group-containing monomer include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline, and one or a mixture of two or more of these can be used. Among these, 2-isopropenyl-2-oxazoline is suitable because it is easily available industrially. The other monomer is not limited as long as it is a monomer that can be copolymerized with the addition-polymerizable oxazoline group-containing monomer, and examples thereof include (meth)acrylic acid esters such as alkyl (meth)acrylates (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, and cyclohexyl groups); unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid, and salts thereof (sodium salts, potassium salts, ammonium salts, tertiary amine salts, etc.); unsaturated nitriles such as acrylonitrile and methacrylonitrile; (meth)acrylamide, N-alkyl (meth)acrylate, etc. Examples of the monomer include unsaturated amides such as t)acrylamide and N,N-dialkyl(meth)acrylamide (the alkyl group can be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, a 2-ethylhexyl group, a cyclohexyl group, and the like); vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; halogen-containing α,β-unsaturated monomers such as vinyl chloride and vinylidene chloride; and α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene. One or more of these monomers can be used. The oxazoline compound may have a polyalkylene oxide chain such as a polyethylene oxide chain, and for example, a (meth)acrylate having a polyalkylene oxide chain may be used as another monomer. From the viewpoint of improving the adhesion of the release layer to the base film, the amount of oxazoline groups in the oxazoline compound is preferably in the range of 0.5 to 10 mmol / g, more preferably 1 to 9 mmol / g, even more preferably 3 to 8 mmol / g, and particularly preferably 4 to 6 mmol / g.

[0095] ((Isocyanate Compounds)) The isocyanate compound is a compound having an isocyanate or an isocyanate derivative structure, such as a blocked isocyanate. Examples of the isocyanate include aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate; aliphatic isocyanates having an aromatic ring, such as α,α,α',α'-tetramethyl xylylene diisocyanate; aliphatic isocyanates such as methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, and hexamethylene diisocyanate; and alicyclic isocyanates such as cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylene bis(4-cyclohexyl isocyanate), and isopropylidenedicyclohexyl diisocyanate. In addition, polymers and derivatives such as biuretized products, isocyanurate products, uretdione products, and carbodiimide modified products of these isocyanates are also included. These may be used alone or in combination. Among the above isocyanates, aliphatic isocyanates or alicyclic isocyanates are more preferable than aromatic isocyanates in order to prevent yellowing due to ultraviolet rays.

[0096] When used in the form of blocked isocyanate, examples of the blocking agent include bisulfites; phenolic compounds such as phenol, cresol, and ethylphenol; alcoholic compounds such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol, and ethanol; active methylene compounds such as isobutanoyl methyl acetate, dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, and acetylacetone; mercaptan compounds such as butyl mercaptan and dodecyl mercaptan; lactam compounds such as ε-caprolactam and δ-valerolactam; amine compounds such as diphenylaniline, aniline, and ethyleneimine; acid amide compounds such as acetanilide and acetic acid amide; and oxime compounds such as formaldehyde oxime, acetaldoxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime. These may be used alone or in combination of two or more.

[0097] The isocyanate compound may be used alone or as a mixture or bond with various polymers. In terms of improving the dispersibility and crosslinking property of the isocyanate compound, it is preferable to use a mixture or bond with a polyester resin or a urethane resin.

[0098] ((Silane coupling compound)) A silane coupling compound is an organosilicon compound that has an organic functional group and a hydrolyzable group such as an alkoxy group in one molecule. For example, epoxy group-containing compounds such as 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; vinyl group-containing compounds such as vinyltrimethoxysilane and vinyltriethoxysilane; styryl group-containing compounds such as p-styryltrimethoxysilane and p-styryltriethoxysilane; (meth)acrylic group-containing compounds such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, and 3-(meth)acryloxypropylmethyldiethoxysilane; 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)- Amino group-containing compounds such as 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-phenyl-3-aminopropyltriethoxysilane; isocyanurate group-containing compounds such as tris(trimethoxysilylpropyl)isocyanurate and tris(triethoxysilylpropyl)isocyanurate; mercapto group-containing compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane.

[0099] When the resin composition further contains component (F), the content thereof is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, as a ratio of the total non-volatile components in the resin composition. By keeping the content of component (F) within the above range, the durability of the release layer is improved.

[0100] (Component (G)) The resin composition for forming the release layer according to the present invention preferably contains a surfactant as component (G) in order to improve the applicability to the substrate film. As the surfactant, from the viewpoint of low foaming and not inhibiting the antistatic properties of the resulting release layer, a nonionic surfactant having one selected from polyalkylene oxide, polyglycerin, and derivatives thereof in its structure is more preferable, a nonionic surfactant having polyalkylene oxide is further preferable, and a nonionic surfactant having polyethylene oxide is particularly preferable.

[0101] Furthermore, as the surfactant, those having a branched alkyl group-substituted acetylene structure or a fluoroalkyl group in the hydrophobic portion are more preferable. An example of the surfactant having a branched alkyl group-substituted acetylene structure in the hydrophobic portion is a nonionic surfactant having a structure having polyethylene oxide in the side chain, as shown in the following formula (4).

[0102] [ka]

[0103] In the above formula (4), m and n are positive numbers indicating the number of moles of ethylene oxide added. In the above formula (4), the average of m+n is preferably 1.3 or more and 30 or less, more preferably 2 or more and 20 or less, and further preferably 4 or more and 10 or less.

[0104] The surfactants may be used alone or in combination of two or more kinds.

[0105] When the resin composition further contains component (G), the content thereof is preferably 0.1 to 20 mass%, more preferably 0.5 to 15 mass%, and even more preferably 2 to 10 mass%, as a ratio of the total non-volatile components in the resin composition. By keeping the content of component (G) within the above range, good coatability is obtained, the transparency of the release layer is maintained, and the durability of the release layer is improved.

[0106] (Other ingredients) In addition to the above components, additives such as a reaction regulator and an adhesion promoter may be further added as appropriate within the scope of the present invention.

[0107] (solvent) The resin composition according to the present invention contains the above-mentioned components (A) to (C), and the optionally added components (D) to (G) and other components, and is preferably diluted with a solvent to form a coating liquid. That is, the liquid coating liquid is applied to a substrate film, and if necessary, dried and cured to form a release layer. The above-mentioned components (A) to (C), and the optionally added components (D) to (G) and other components constituting the resin composition may be dissolved in a solvent, or may be dispersed in the solvent. When a coating liquid is prepared, the concentration of all non-volatile components of the resin composition in the coating liquid is preferably 0.1 to 50% by mass. If it is 0.1% by mass or more, a release layer of a desired thickness can be efficiently formed. On the other hand, if it is 50% by mass or less, it is easy to dissolve or disperse in a solvent, and coating is easy. From the above viewpoints, the concentration of all non-volatile components of the resin composition in the coating liquid is more preferably 0.5 to 30% by mass, and even more preferably 1 to 15% by mass.

[0108] The solvent is not particularly limited, and either water or an organic solvent can be used. From the viewpoint of environmental protection, it is preferable to use water as the main solvent (50% by mass or more). That is, it is preferable to use the resin composition according to the present invention as an aqueous coating liquid for forming a release layer. The water content is preferably 60% by mass or more, more preferably 70% by mass or more. The aqueous coating liquid may contain a small amount of an organic solvent. The specific amount of the organic solvent is preferably less than that of water on a mass basis, and is, for example, less than 30% by mass, preferably less than 20% by mass, more preferably less than 10% by mass in the solvent. Examples of organic solvents used in combination with water include alcohols such as ethanol, isopropanol, ethylene glycol, and glycerin; ethers such as ethyl cellosolve, t-butyl cellosolve, propylene glycol monomethyl ether, and tetrahydrofuran; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; and amines such as dimethylethanolamine. These can be used alone or in combination. By appropriately selecting and adding these organic solvents to the aqueous coating liquid as necessary, the stability and coatability of the coating liquid may be improved.

[0109] In addition, when only an organic solvent is used as the solvent, examples of such an organic solvent include aromatic hydrocarbons such as toluene, aliphatic hydrocarbons such as hexane, heptane, isooctane, esters such as ethyl acetate, butyl acetate, ketones such as ethyl methyl ketone, isobutyl methyl ketone, alcohols such as ethanol, 2-propanol, ethers such as diisopropyl ether, dibutyl ether, etc. These may be used alone or in combination, taking into consideration solubility, coatability, boiling point, etc.

[0110] It can be assumed that the release layer contains unreacted compounds of the above components (A) to (C), reacted compounds, or a mixture thereof.

[0111] (Method of producing release film (method of forming release layer)) The method for forming a release layer according to the present invention will be described below. The method for forming the release layer is not particularly limited, and any conventionally known coating method such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating, etc. can be used. The method for forming the release layer includes in-line coating and off-line coating. The drying and curing conditions are not particularly limited, and for example, when the release layer is provided by off-line coating, it is usually recommended to perform heat treatment at 80 to 200°C for 3 to 40 seconds, preferably at 140 to 180°C for 3 to 40 seconds. On the other hand, when the release layer is provided by in-line coating, it is usually recommended to perform heat treatment at 70 to 280°C for 3 to 200 seconds.

[0112] In the present invention, the release layer is preferably formed by in-line coating, which treats the surface of the polyester film during the film-forming process. In-line coating is a method of coating within the polyester film production process, specifically, coating at any stage from melt extrusion of polyester to stretching, heat setting and winding up. Usually, coating is performed on any of the following: an unstretched sheet obtained by melting and quenching, a stretched uniaxially stretched film, a biaxially stretched film before heat setting, or a film after heat setting and before winding up. Although not limited to the following, for example, in the case of sequential biaxial stretching, a method in which a uniaxially stretched film stretched in the longitudinal direction (machine direction) is coated and then stretched in the transverse direction is particularly advantageous. This method has the advantage of being able to simultaneously form the film and the release layer, and is advantageous in terms of production costs. In addition, since stretching is performed after coating, the thickness of the release layer can be changed by the stretching ratio, and thin film coating can be performed more easily than with off-line coating films. Furthermore, by providing a release layer on the film before stretching, the release layer can be stretched together with the polyester film, thereby allowing the release layer to adhere firmly to the polyester film. Furthermore, in the production of biaxially stretched polyester film, the film can be restrained in the vertical and horizontal directions by stretching while holding the film ends with clips or the like, and high temperatures can be applied in the heat fixing process while maintaining flatness without wrinkles or the like. Therefore, the heat treatment performed after coating can be performed at a high temperature that cannot be achieved by other methods, improving the film-forming properties of the release layer and allowing the release layer and the polyester film to adhere more firmly. Furthermore, a strong release layer can be formed, and the performance such as migration resistance and moist heat resistance to various functional layers that can be formed on the release layer can be improved.

[0113] Regardless of whether off-line coating or in-line coating is used, heat treatment and irradiation with active energy rays such as ultraviolet rays may be used in combination as necessary. The polyester film constituting the laminated polyester film of the present invention may be previously subjected to a surface treatment such as a corona treatment or a plasma treatment.

[0114] The coating amount of the non-volatile component of the release layer is preferably 1 to 300 mg / m 2 , more preferably 5 to 150 mg / m 2 , and more preferably 10 to 75 mg / m 2 , and particularly preferably 20 to 50 mg / m 2 When the coating amount of the release layer is within the above range, appropriate releasability for the pressure-sensitive adhesive layer can be ensured.

[0115] From the viewpoint of handleability, the total thickness of the release film of the present invention is preferably 200 μm or less, more preferably 5 μm or more and 125 μm or less, even more preferably 8 μm or more and 100 μm or less, and particularly preferably 12 μm or more and 75 μm or less.

[0116] (Release film properties) The haze of the release film of the present invention is preferably 10% or less, more preferably 5% or less, even more preferably 2.0% or less, and particularly preferably 1.0% or less. By being in the above range, inspection with the release film of the present invention attached can be easily performed in the manufacturing and processing steps using the release film of the present invention.

[0117] The peel strength between the release layer of the release film of the present invention and an acrylic adhesive tape ("No. 31B" manufactured by Nitto Denko Corporation) can be evaluated by the measurement method described in the Examples below. The peel strength evaluated in this manner can be easily adjusted by adjusting the content of the release agent. When light peeling is desired, a peel strength of 500 mN / cm or less can be said to be good, but a peel strength of 200 mN / cm or less is preferable, and a peel strength of 110 mN / cm or less is more preferable. There is no particular restriction on the lower limit, but from the viewpoint of avoiding unintended peeling when attached to an adhesive layer, for example, the lower limit is preferably 20 mN / cm or more, and more preferably 40 mN / cm or more.

[0118] The antistatic property of the release film of the present invention can be evaluated by the surface resistivity measured on the surface of the release layer provided on the surface of the base film. The lower the surface resistivity of the surface of the release film (the surface of the release layer), the better the antistatic property. The surface resistivity can be measured by the method described in the examples below. Surface resistivity is 1×10 12 If the resistance is less than 1×10 Ω / □, it can be said to have antistatic properties. 10 If it is less than Ω / □, it can be said that the antistatic property is good, and if it is less than 1×10 8 If the resistance is less than 1×10 Ω / □, it is considered to have excellent antistatic properties and is therefore preferable. 6 If it is Ω / □ or less, it can be said that the antistatic performance is particularly good. Although there is no particular lower limit for the surface resistivity, taking into account the cost required for manufacturing this film, a lower limit of 1×10 4 It is preferable that the resistance is Ω / □ or more.

[0119] In the release film of the present invention, the surface resistivity of the release layer is R x The surface of the release layer was rubbed with a nonwoven fabric made of cupra five times under a load of 680 g, and the surface resistivity of the release layer was then R Y The ratio of surface resistivities (R Y / R x ) is preferably 4.0 or less, more preferably 3.0 or less, and even more preferably 2.0 or less. The friction of the surface of the release layer of the release film can be measured using a rubbing tester by the method described later in the Examples section. For example, in the manufacturing process of display panels, when the film is transported with the release film attached, friction occurs due to contact between the guide roll and the film surface, which may deteriorate the antistatic performance. Y / R x ) in this range, deterioration of antistatic performance due to friction or the like can be suppressed, and the antistatic agent can be used without any problem in practical use.

[0120] The above-mentioned compounds and components in the release layer can be analyzed by, for example, TOF-SIMS, ESCA, fluorescent X-ray analysis, or the like.

[0121] <Film laminate> The film laminate of the present invention has a configuration in which the release film is bonded to an optical member via an adhesive layer.

[0122] [Adhesive layer] The adhesive for forming the adhesive layer can be an acrylic adhesive, a urethane adhesive, a synthetic rubber adhesive, a natural rubber adhesive, a silicone adhesive, a polyester adhesive, a vinyl alkyl ether adhesive, an epoxy adhesive, etc. Among them, an acrylic adhesive, a urethane adhesive, and a silicone adhesive are preferred, and from the viewpoint of heat resistance and transparency, a silicone adhesive is more preferred. In addition, as long as the optical properties are not adversely affected, two or more kinds of materials can be mixed and used, or two or more layers can be used. The pressure-sensitive adhesive may be of any of an emulsion type, a solvent type, or a solventless type, and may be of any of a crosslinked type or a non-crosslinked type. Furthermore, the adhesive layer can be formed by adding particles such as fillers or additives to the adhesive.

[0123] [Optical components] The optical member is a resin film or a glass substrate. The resin film is preferably a resin film selected from the group consisting of a polyester film, a polyimide film, and a cyclic polyolefin film. In addition, it is preferable that the resin film is a laminated film in which a functional layer is provided on the surface of the resin film that is in contact with the adhesive layer. The functional layer is preferably a release layer, which is a layer different from the release layer in the release film of the present invention, and is hereinafter referred to as "another release layer" for convenience.

[0124] The "other release layer" preferably contains a curable silicone resin from the viewpoint of releasability from the adhesive layer. An example of the "other release layer" is one having, in sequence, a first layer formed from a silicone composition containing as its main component a curable silicone resin that does not contain a fluorine substituent, and a second layer containing a component having a fluorine substituent.

[0125] Another example of the "other release layer" is a layer formed from a silicone composition containing, as a main component, a curable silicone resin containing a fluorine substituent.

[0126] Furthermore, another example of the "other release layer" is a layer formed from a silicone composition containing, as a main component, a curable silicone resin that does not contain a fluorine substituent.

[0127] The term "main component" used herein refers to the component that has the largest mass ratio among the constituent components.

[0128] From the viewpoint of handleability, the total thickness of the film laminate of the present invention is preferably 200 μm or less, more preferably 9 μm or more and 125 μm or less, even more preferably 12 μm or more and 125 μm or less, and particularly preferably 25 μm or more and 125 μm or less.

[0129] (Method of manufacturing film laminate) The method for producing the film laminate of the present invention is not particularly limited, but for example, the adhesive layer-forming liquid is applied to the release layer of the release film of the present invention with an applicator to form an adhesive layer, and then another resin film or a glass substrate is laminated onto the adhesive layer to produce the film laminate of the present invention. The method for applying the adhesive layer-forming liquid is not particularly limited, and can be performed by a conventionally known method. As described above, the other resin film may have a functional layer on the surface in contact with the adhesive layer.

[0130] <Applications of release films and film laminates> Since the release film of the present invention has excellent releasability and antistatic properties, it can be suitably used in the following forms, although the present invention is not limited to such uses. In a film laminate having a configuration in which the release film of the present invention is laminated on one side of an adhesive layer and a release film having a higher peel strength than the release film is laminated on the opposite side of the adhesive layer, the release film of the present invention can be peeled off, the exposed adhesive layer surface is attached to an adherend such as an optical member, the adhesive layer is cured, and then the release film having a higher peel strength is peeled off. However, the use method is not limited to this.

[0131] The adherend may be an optical member, such as a resin film selected from a polyester film, a polyimide film, or a cyclic polyolefin film, or a glass substrate, as described above.

[0132] Furthermore, when the release film of the present invention is peeled off from an adherend, such as an optical component constituting a display panel, the release film can be peeled off smoothly with minimal damage to the adherend, and therefore can be suitably used for display panels. EXAMPLES

[0133] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples without departing from the gist of the present invention. The measurement and evaluation methods used in the present invention are as follows.

[0134] <Evaluation method> (1) Intrinsic viscosity (IV) of polyester 1 g of polyester from which components incompatible with polyester had been removed was weighed out precisely, dissolved in 100 mL of a mixed solvent of phenol / tetrachloroethane = 50 / 50 (weight ratio), and the intrinsic viscosity (IV) was measured at 30°C using a viscosity measuring device (Rigo Co., Ltd., "VMS-022UPC·F10").

[0135] (2) Average particle size of particles in the base film The substrate films of the examples and comparative examples were observed using a transmission electron microscope (TEM) (Hitachi High-Technologies Corporation, "H-7650", acceleration voltage 100 kV), and the average particle size of 10 particles was taken as the average particle size.

[0136] (3) Concentration of non-volatile components in coating solution The measurements were performed using a halogen moisture meter ("HR73" manufactured by Mettler Toledo K.K.) at 105°C for 60 minutes.

[0137] (4) Coating amount of release layer The calculation was based on the concentration of non-volatile components in the coating solution, the coating amount before drying derived from the consumption amount of the coating solution, the transverse stretching ratio, etc.

[0138] (5) Film haze Measurements were made in accordance with JIS K 7136 using a haze meter ("HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd.).

[0139] (6) Peel strength of release layer The adhesive surface of a 5 cm wide adhesive tape ("No. 31B" manufactured by Nitto Denko Corporation) was pressed against the release layer surface of the release films obtained in the Examples and Comparative Examples by rolling a rubber roller with a load of 2 kg back and forth once, and the peel strength was measured after leaving the tape for 1 hour at 23° C. The peel strength was measured using a small tabletop tester "AGX-plus" (manufactured by Shimadzu Corporation) by 180° peeling under conditions of an atmospheric temperature of 23° C. and a tensile speed of 300 mm / min.

[0140] (7) Surface resistivity of release layer The release films obtained in the examples and comparative examples were conditioned for 30 minutes in a measurement atmosphere of 23°C and 50% RH, and the surface resistivity of the release layer surface was measured using a four-point ESP probe in a low resistivity meter (Loresta GP MCP-T600 manufactured by Nitto Seiko Analytech Co., Ltd.). The resistivity correction factor (RCF value) was fixed at 4.235.

[0141] (8) Friction treatment of release layer Using a rubbing tester (manufactured by Ohira Rika Kogyo Co., Ltd.), a 5 cm x 7 cm flat frictional element was wrapped with 4 layers of 5 cm x 10 cm cupra nonwoven fabric ("Bencotto M-3II" manufactured by Ozu Sangyo Co., Ltd.) without slack, and the release layer surface of the release film obtained in the examples and comparative examples was rubbed five times back and forth (within a 15 cm long range) with a load of 680 g, and then the surface resistivity was measured. The method for measuring the surface resistivity is as described in (7). In addition, the surface resistivity of the release layer obtained in (7) is R x The surface resistivity of the release layer after the friction treatment is R Y The ratio of surface resistivities (R Y / R x ) was calculated.

[0142] (9) Average particle size of fluororesin particles or silica particles Using a particle size distribution meter (ELSZ-2000ZS manufactured by Otsuka Electronics Co., Ltd.) based on the dynamic light scattering method, the concentration of the sample was adjusted with pure water so as to obtain the optimal light intensity, and the average particle size was measured. The particle size in the present invention is the particle size at 50% of the cumulative volume (D50) measured in this manner.

[0143] <Materials used> The polyester raw materials for the base films used in the examples and comparative examples are as follows:

[0144] [Polyester (1)] Substantially particle-free polyethylene terephthalate with an intrinsic viscosity of 0.64 dL / g

[0145] [Polyester (2)] Polyethylene terephthalate with an intrinsic viscosity of 0.65 dL / g containing 0.2% by mass of amorphous silica with an average particle size of 2.4 μm

[0146] The following components were used as the resin composition for forming the release layer. (Component (A)) A1: Conductive agent "AS-G1" (manufactured by Shin-Etsu Polymer Co., Ltd., mainly composed of polyethylenedioxythiophene and polystyrenesulfonic acid) was neutralized with concentrated ammonia water to a pH of 9.

[0147] (Component (B)) B1: A water dispersion of a long-chain alkyl group-containing compound obtained by reacting polyvinyl alcohol with an average polymerization degree of 500 and a saponification degree of 88 mol% with an excess of octadecyl isocyanate, purifying the reacted polyvinyl alcohol, and dispersing the purified polyvinyl alcohol in water using a nonionic dispersant.

[0148] (Component (C)) C1: Water dispersion of FEP particles with an average particle size of 119 nm ("Neoflon FEP ND-110" manufactured by Daikin Industries, Ltd.) C2: Water dispersion of PTFE particles with an average particle size of 168 nm ("Polyflon PTFE D-210C" manufactured by Daikin Industries, Ltd.) The average particle sizes are all values ​​measured by the method described above in (9).

[0149] (Component (D)) D1: Water dispersion of polyester resin copolymerized with the following composition Monomer composition: (Acid component) 2,6-naphthalenedicarboxylic acid / 5-sodium sulfoisophthalic acid = 92 / 8 (molar ratio) (Diol component) Ethylene glycol / diethylene glycol = 80 / 20 (molar ratio)

[0150] (Component (E)) E1: Polyglycerol in the formula (3) where n is 4 on average E2: Sorbitol

[0151] (Component (F)) F1: Polymethylol melamine F2: Polyglycerol polyglycidyl ether

[0152] (Component (G)) G1: A nonionic surfactant having a structure having polyethylene oxide in the side chain, in which the average of m+n in the above formula (4) is 10. G2: A fluorine-based nonionic surfactant with a structure that has a branched perfluoroalkenyl group in the hydrophobic group and a polyethylene oxide chain (average chain length 8 units) in the hydrophilic group.

[0153] (Comparison component (H)) H1: Spherical silica particles with an average particle size of 67 nm The average particle size is a value measured by the method (9) above.

[0154] Example 1 A blend of polyester (1) and polyester (2) in a weight ratio of 92 / 8 was used as the raw material for layer A, and polyester (1) alone was used as the raw material for layer B, which were fed into an extruder, heated and melted at 285°C, and co-extruded to a thickness ratio of A / B / A=5 / 90 / 5 under extrusion conditions, with layer A being the outermost layer (surface layer) and layer B being the middle layer, and then cooled and solidified while being in close contact with a mirror-finished cooling drum with a surface temperature of 40-50°C to prepare an unstretched film. This film was stretched 3.7 times in the longitudinal direction while passing through a group of heating rolls at 85°C to produce a uniaxially stretched film. Resin composition 1 (coating solution 1, non-volatile component concentration 4.4% by mass) having the composition shown in Table 1 below was applied to one side of this uniaxially stretched film, and then this film was introduced into a tenter stretching machine and stretched 4.3 times in the width direction at 100°C. It was then further subjected to heat treatment at 230°C and then to a relaxation treatment of 2% in the width direction. After drying, the coating amount was 46 mg / m 2 Thus, a biaxially stretched film having a thickness of 50 μm and a release layer of this composition was obtained, obtaining the release film of Example 1. The evaluation results of this release film are shown in Table 2 below.

[0155] (Examples 2 to 11, Comparative Examples 1 to 3) Release films of Examples 2 to 11 and Comparative Examples 1 to 3 were obtained in the same manner as in Example 1, except that the resin composition for forming the release layer was changed to the composition shown in Table 1. The evaluation results are shown in Table 2.

[0156] [Table 1]

[0157] [Table 2]

[0158] The release films obtained in Examples 1 to 11 of the present invention had excellent releasability and antistatic properties, and were also excellent in transparency. In particular, it was found that they had excellent abrasion resistance. Compared with Examples 1 to 11, Comparative Example 1, in which the fluororesin particles of component (C) were not added, and Comparative Examples 2 and 3, in which silica particles were added instead of the fluororesin particles, were inferior in abrasion resistance. The release film obtained by the present invention has excellent releasability and antistatic properties, and also has excellent abrasion resistance, and is therefore of great industrial utility.

Claims

1. A release film having a release layer formed on at least one surface of a base film from a resin composition containing the following components (A), (B) and (C), wherein the ratio (R Y / R x ) of the surface resistivity (R x ) of the release layer to the surface resistivity (R Y ) of the release layer after the surface of the release layer is rubbed five times with a cupra nonwoven fabric at a load of 680 g is 4.0 or less. Component (A): (a1) at least one selected from a polymer obtained by doping a compound made of thiophene or a thiophene derivative with another anionic compound, and (a2) a self-doped polymer having an anionic group in a compound made of thiophene or a thiophene derivative. Component (B): Release agent Component (C): Fluorine resin particles

2. A release film having a release layer formed from a resin composition containing the following components (A), (B), and (C) on at least one surface of a base film, wherein after an acrylic adhesive tape ("No. 31B" manufactured by Nitto Denko Corporation) is attached to the release layer and left at 23°C for 1 hour, the 180° peel strength measured under conditions of 23°C and a tensile speed of 300 mm / min is 200 mN / cm or less. Component (A): (a1) at least one selected from a polymer obtained by doping a compound made of thiophene or a thiophene derivative with another anionic compound, and (a2) a self-doped polymer having an anionic group in a compound made of thiophene or a thiophene derivative. Component (B): Release agent Component (C): Fluorine resin particles

3. 3. The release film according to claim 1, wherein the release agent of the component (B) is at least one member selected from the group consisting of long-chain alkyl group-containing compounds and waxes.

4. The release film according to any one of claims 1 to 3, wherein the fluororesin particles of the component (C) are one or more selected from the group consisting of hexafluoropropylene-tetrafluoroethylene copolymers and polytetrafluoroethylene.

5. The release film according to any one of claims 1 to 4, wherein the average particle size of the fluororesin particles of the component (C) is 10 to 1000 nm.

6. The release film according to any one of claims 1 to 5, wherein the content of the fluororesin particles of the component (C) is 0.1 to 20 mass% as a ratio of all non-volatile components in the resin composition.

7. A release film described in any one of claims 1 to 6, wherein the content of component (A) is 0.1 to 30 mass% as a ratio to all non-volatile components in the resin composition.

8. A release film described in any one of claims 1 to 7, wherein the content of the release agent of component (B) is 1 to 80 mass% as a percentage of all non-volatile components in the resin composition.

9. The release film according to any one of claims 1 to 8, wherein the resin composition further contains a binder resin as a component (D).

10. 10. The release film according to claim 9, wherein the binder resin of the component (D) is at least one selected from the group consisting of polyurethane resins, polyester resins, and acrylic resins.

11. A release film as described in claim 9 or 10, wherein the content of the binder resin of component (D) is 1 to 60 mass % as a ratio to all non-volatile components in the resin composition.

12. The release film according to any one of claims 1 to 11, wherein the resin composition further contains, as a component (E), one or more selected from glycerin, polyglycerin, an alkylene oxide adduct of the glycerin or the polyglycerin, a sugar alcohol, and a sugar alcohol condensate.

13. A release film as described in claim 12, wherein the content of component (E) is 10 to 95 mass% as a ratio to all non-volatile components in the resin composition.

14. The release film according to any one of claims 1 to 13, wherein the base film is a polyester film.

15. A film laminate in which a release film having a release layer formed from a resin composition containing the following components (A), (B) and (C) is attached to at least one surface of a base film and an optical component via an adhesive layer. Component (A): (a1) at least one selected from a polymer obtained by doping a compound made of thiophene or a thiophene derivative with another anionic compound, and (a2) a self-doped polymer having an anionic group in a compound made of thiophene or a thiophene derivative. Component (B): Release agent Component (C): Fluorine resin particles

16. The film laminate according to claim 15, wherein the content of said component (A) is 0.1 to 30 mass% in relation to all non-volatile components in the resin composition, the content of said release agent of said component (B) is 1 to 80 mass% in relation to all non-volatile components in the resin composition, and the content of said fluororesin particles of said component (C) is 0.1 to 20 mass% in relation to all non-volatile components in the resin composition.

17. A film laminate as described in claim 15 or 16, wherein the resin composition further contains a binder resin as component (D), and the content of the binder resin of component (D) is 1 to 60 mass% as a ratio to all non-volatile components in the resin composition.

18. A film laminate described in any one of claims 15 to 17, wherein the resin composition further contains one or more components selected from glycerin, polyglycerin, alkylene oxide adducts of the glycerin or polyglycerin, sugar alcohols, and sugar alcohol condensates as component (E), and the content of component (E) is 10 to 95 mass% as a proportion of all non-volatile components in the resin composition.

19. The film laminate according to any one of claims 15 to 18, wherein the optical member is a resin film or a glass substrate.

20. The film laminate according to claim 19, wherein the resin film is selected from the group consisting of a polyester film, a polyimide film, and a cyclic polyolefin film.

21. The film laminate according to claim 19 or 20, which is a laminate film having a functional layer provided on a surface of the resin film that contacts the pressure-sensitive adhesive layer.

22. 22. The film laminate of claim 21, wherein the functional layer is another release layer.

23. 23. The film laminate of claim 22, wherein the other release layer comprises a curable silicone resin.

24. The film laminate according to any one of claims 15 to 23, having a total thickness of 200 µm or less.

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