Laminated film and method for producing same

Abstract

A laminated film in which a resin layer is provided on at least one surface of a base film, the base film surface on which the resin layer is provided substantially does not contain particles, the resin layer contains an acid-modified polyolefin resin (A) and a crosslinking agent (C), and the expanded interface area ratio (Sdr) of the resin layer surface as determined by a non-contact surface shape measurement machine is 0.025-0.304%. And a maximum height (Sz) of 0.01 to 0.50 [mu] m.

Description

TECHNICAL FIELD

[0001] The present application relates to a layered film and a method for producing the same. BACKGROUND

[0002] Recently, in electronic information instruments, miniaturization and high integration are advancing, and process films used in the production of electronic information instruments are required to have excellent flatness.

[0003] Patent Document 1 discloses a slip film which has excellent flatness of a resin layer, excellent slip property at the time of film formation / processing, and is suitable as a release material.

[0004] The base film constituting the slip film disclosed in Patent Document 1 contains particles in order to impart slip property. However, a resin layer is formed on the base film containing particles, and therefore the shape of the particles appears on the surface of the resin layer, which can be transferred to an adherend, and there is room for further improvement in terms of high flatness required for miniaturization of electronic information instruments.

[0005] For a layered film in which a resin layer is formed on a base film, if the content of particles in the base film is reduced or the particle diameter of the particles is reduced in order to improve the flatness of the surface of the resin layer, there is a tendency that the slip property of the surface of the base film decreases. On the other hand, if the content of particles in the base film is increased to improve the slip property of the surface of the base film, there is a tendency that the flatness of the surface of the resin layer decreases. In this way, it is difficult to obtain a layered film which has both flatness and slip property and the like at a high level.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT DOCUMENTS

[0008] Patent Document 1: Japanese Patent Application Publication No. 2012-020429 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] The present application was made in view of these problems, and aims to provide a layered film in which a resin layer provided on a base film exhibits excellent release property with respect to an adherend, has excellent flatness which is not transferred to the adherend, and has excellent slip property at the time of film formation and processing.

[0011] MEANS FOR SOLVING THE PROBLEMS

[0012] The present inventors and others made intensive studies in order to solve the above problems, and as a result, found that if a resin layer is formed on a base film which does not substantially contain particles using a liquid resin layer-forming material containing a specific compound, a layered film which has both flatness and slip property at a high level and also has excellent release property can be obtained, thereby achieving the present application.

[0013] The present application relates to a laminate film provided with a resin layer on at least one side of a base film, and the laminate film is characterized in that

[0014] The surface of the base film provided with the resin layer is substantially free of particles,

[0015] The resin layer contains an acid-modified polyolefin resin (A) and a crosslinking agent (C),

[0016] The resin layer has a spread interface area ratio (Sdr) of 0.025 to 0.304% and a maximum height (Sz) of 0.01 to 0.50 μm as measured by a non-contact surface shape measuring machine.

[0017] According to the laminate film of the present application, the olefin component of the acid-modified polyolefin resin (A) preferably contains propylene or 1-octene.

[0018] According to the laminate film of the present application, the content of propylene in the olefin component is preferably 70% by mass or more.

[0019] According to the laminate film of the present application, the content of 1-octene in the olefin component is preferably 15% by mass or more.

[0020] According to the laminate film of the present application, the peel strength between the resin layer and the epoxy prepreg is preferably 0.5 N / cm or less.

[0021] The production method of the laminate film of the present application is a method for producing the above-described laminate film, and the method is characterized in that the method includes:

[0022] a step of coating the base film with a resin layer-forming liquid at a temperature of 20 to 40°C, the resin layer-forming liquid containing an acid-modified polyolefin resin (A), a crosslinking agent (C), and a compound (D) selected from at least one of an amphiphilic oligomer, an alkyne diol, and an oxirane adduct of an alkyne diol; and

[0023] a step of drying and stretching the base film coated with the resin layer-forming liquid.

[0024] According to the production method of the laminate film of the present application, it is appropriate that the content of the compound (D) is 2 to 50 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin (A) in the resin layer-forming liquid.

[0025] Effects of the Invention

[0026] The laminated film of the present application is excellent in flatness of the surface on the resin layer side, has good mold releasability, and has easy slidability suitable for film production / processing, and thus is suitably used as a mold release film in various applications such as double-sided adhesive tape, a protective film for an adhesive material, a protective material or a process material for manufacturing a component for a liquid crystal display, a printed wiring board, and the like, an ion exchange film, a ceramic green sheet, a sheet-shaped structure for a heat sink, and the like. DETAILED DESCRIPTION

[0027] The present application is described in detail below.

[0028] The laminated film of the present application is provided with a resin layer on at least one substrate film surface substantially free of particles. The resin layer contains an acid-modified polyolefin resin (A) and a crosslinking agent (C), and has a spread interface area ratio (Sdr) of 0.025 to 0.304% as measured by a non-contact surface shape measuring machine, and a maximum height (Sz) of 0.01 to 0.50 μm as measured by a non-contact surface shape measuring machine.

[0029] <Substrate Film>

[0030] As the substrate film constituting the laminated film of the present application, for example, a polyester film such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), poly(l,4-cyclohexyldimethylene terephthalate), polylactic acid (PLA), a polyolefin film such as polypropylene, a polystyrene film, polyamide 6, poly(m-xylylene adipamide) (MXD6 nylon), polyamide 66, polyamide 46, polyamide 4T, polyamide 6T, polyamide 9T, polyamide 10T, polyamide 11T, polyamide 12T, polyamide 6I, a polycarbonate film, an acrylonitrile film, a polyimide film, a multilayer body thereof (e.g., polyamide 6 / MXD6 nylon / polyamide 6, polyamide 6 / ethylene-vinyl alcohol copolymer / polyamide 6, polyamide 6 / 6T, polyamide 6 / 6I, polyamide 6 / 6T / 6I), or a mixture thereof, and the like, preferably a polyester film, a polyamide film having mechanical strength and dimensional stability. Here, T represents terephthalic acid, and I represents isophthalic acid. Of these, the substrate film is preferably a polyethylene terephthalate film from the viewpoint of adhesion to the resin layer, and is preferably a semi-aromatic polyamide film from the viewpoint of heat resistance and adhesion to the resin layer, and is particularly preferably a polyamide 9T film or a polyamide 10T film.

[0031] (Polyester Resin)

[0032] The polymerization method of the polyester resin constituting the substrate film is not particularly limited, and examples include transesterification and direct polymerization. Regarding transesterification catalysts, examples include oxides and acetates of Mg, Mn, Zn, Ca, Li, Ti, etc. Regarding polycondensation catalysts, examples include oxides and acetates of Sb, Ti, Ge, etc.

[0033] The polymerized polyester resin contains monomers, oligomers, and acetaldehyde as a byproduct, so it can undergo solid-phase polymerization at temperatures above 200°C under reduced pressure or with inactive gas flow.

[0034] The intrinsic viscosity of the polyester resin is preferably 0.55 to 0.80, more preferably 0.60 to 0.75. If the intrinsic viscosity of the polyester resin is less than the above range, it is prone to breakage during film formation, making stable film formation difficult and resulting in low film strength. On the other hand, if the intrinsic viscosity of the polyester resin exceeds the above range, the shear heat generated during resin melt extrusion in the film production process increases, placing a greater load on the extruder. This can lead to reduced film productivity, such as having to sacrifice production speed or difficulty in controlling film thickness. In addition, the resulting film exhibits increased thermal decomposition, gelation, surface defects, foreign matter, and surface rough protrusions. Furthermore, excessively high intrinsic viscosity increases polymerization time and process time, also contributing to increased costs.

[0035] (Semi-aromatic polyamide resin)

[0036] The semi-aromatic polyamide resin constituting the substrate film is composed of dicarboxylic acid components and diamine components, and contains aromatic components in the dicarboxylic acid components or diamine components, preferably composed of aromatic dicarboxylic acid components and aliphatic diamine components.

[0037] (Manufacturing of substrate film)

[0038] Next, the manufacturing method of the substrate film will be explained.

[0039] First, fully dried resin is fed into an extruder and fully plasticized, then melted at a temperature above which it exhibits fluidity. The melt is then passed through a selected filter as needed. The molten polymer is then extruded in sheets through flat dies such as T-die or I-die, and adhered to the cooling surface of a moving cooling body, such as a cooling roller or steel belt, whose temperature has been adjusted below the glass transition temperature (Tg), to obtain an unstretched film. Methods for adhering the extruded sheet-like molten polymer to the moving cooling body for cooling and solidification include air knife casting, electrostatic application, and vacuum chamber methods.

[0040] The obtained unstretched film is preferably stretched, i.e., uniaxially oriented by a uniaxial stretching method or biaxially oriented by a biaxial stretching method, from the viewpoint of improving mechanical properties and improving heat resistance. As for the biaxial stretching method, there is no particular limitation, and a flat-type sequential biaxial stretching method, a flat-type simultaneous biaxial stretching method, an inflation method, or the like can be used.

[0041] Among them, the flat-type sequential biaxial stretching method is most suitable in the stretching of the polyester film, and the flat-type simultaneous biaxial stretching method is most suitable in the stretching of the semi-aromatic polyamide film.

[0042] In the uniaxial stretching method of the polyester film, the unstretched film is stretched in the length or width direction at a temperature ranging from the Tg of the resin to a temperature 50°C higher than the Tg at a stretching ratio of about 2 to 6 times.

[0043] In the simultaneous biaxial stretching method, the unstretched film is biaxially stretched in the length and width directions at a temperature ranging from the Tg of the resin to a temperature 50°C higher than the Tg at a stretching ratio of about 2 to 4 times. Before being introduced into the simultaneous biaxial stretching machine, the unstretched film can also be subjected to a preliminary longitudinal stretching of about 1.2 times.

[0044] In addition, in the sequential biaxial stretching method, the unstretched film is heated by a heating roller, infrared rays, or the like, stretched in the length direction to obtain a longitudinal stretched film. The longitudinal stretching is preferably performed using a difference in rotational speed of two or more rollers to make the stretching ratio 2.5 to 4.0 times at a temperature ranging from the Tg of the polyester to a temperature 40°C higher than the Tg. The longitudinal stretched film is continuously subjected to the processes of transverse stretching, heat setting, and heat relaxation in the width direction in this order to form a biaxially oriented film. The transverse stretching is started at a temperature ranging from the Tg of the resin to a temperature 40°C higher than the Tg, and the maximum temperature is preferably a temperature lower than the melting point (Tm) of the resin by (100 to 40) °C. The stretching ratio of the transverse stretching is adjusted depending on the required properties of the final film, and is preferably set to 3.5 times or more, further preferably 3.8 times or more, and more preferably 4.0 times or more. After stretching in the length and width directions, further re-stretching in the length direction and / or the width direction can be performed, whereby the elastic modulus of the film can be improved, or the dimensional stability can also be improved.

[0045] After the stretching, heat setting treatment is preferably performed at a temperature lower than the Tm of the resin by (50 to 10) °C for several seconds, and simultaneously with the heat setting treatment, relaxation of 1 to 10% in the film width direction is performed. After the heat setting treatment, the film is cooled to below the Tg to obtain a biaxially stretched film.

[0046] In the stretching of the semi-aromatic polyamide film, as described above, since the film thickness accuracy is good and the physical properties in the film width direction are uniform, a flat simultaneous biaxial stretching method is most suitable. As a stretching device for the flat simultaneous biaxial stretching method, a screw-type tenter, a pantograph-type tenter, a linear motor-driven clamp-type tenter, or the like can be used.

[0047] As for the stretching ratio, in order to make the heat resistance and mechanical strength of the finally obtained semi-aromatic polyamide film excellent, it is preferable that the stretching ratio in the length direction and the width direction be each 1.5 to 10 times, and more preferably 2 to 5 times.

[0048] As for the stretching speed, it is preferable that the stretching strain speed in the length direction and the width direction each exceed 400% / minute, and more preferably be 800 to 12000% / minute, and more preferably 1200 to 6000% / minute. If the strain speed is 400% / minute or less, the film is broken by crystal growth during the stretching, and on the contrary, if the strain speed is too fast, there is a case where the un-stretched sheet cannot follow the deformation and is broken.

[0049] The stretching temperature is preferably Tg or higher of the semi-aromatic polyamide resin, and more preferably exceeds Tg and is (Tg + 50)0C or lower. If the stretching temperature is lower than Tg, the film is easily broken, and stable production cannot be performed, and on the contrary, if it exceeds (Tg + 50)0C, there is a case where stretching unevenness occurs.

[0050] After the semi-aromatic polyamide film is subjected to the above-described stretching, it is preferable that the film be held by a clamp used at the time of the stretching, and heat setting treatment be performed as necessary. The preferable heat setting treatment temperature is 250 to (Tm - 5)0C, and more preferably 280 to (Tm - 10)0C. If the heat setting treatment temperature is lower than 2500C, the curing reaction of the resin layer containing the acid-modified olefin resin provided on the semi-aromatic polyamide film before the stretching becomes insufficient, and the releasability is reduced.

[0051] Further, after the heat setting treatment is performed, the film is preferably subjected to relaxation treatment of 1 to 10% while being held by the clamp, and more preferably relaxation treatment of 3 to 7%. By performing the relaxation treatment, the film can obtain sufficient dimensional stability.

[0052] After the heat setting treatment and the relaxation treatment are performed as necessary, cooling is performed, and the semi-aromatic polyamide resin stretched film roll is obtained by winding on a winding roll. The obtained semi-aromatic polyamide resin stretched film roll can be divided into a desired width.

[0053] (Substrate film of a multi-layered structure)

[0054] By the above-described production method, a substrate film of a single-layered structure can be obtained, but the substrate film can also be a film of a multi-layered structure in which two or more layers are stacked.

[0055] The multilayer film can be produced in the above production method by melting the resins constituting each layer separately, using a multilayer die to perform extrusion, and performing biaxial stretching, heat setting after laminating and fusion bonding before curing, or by melting, extruding and separately filmizing two or more kinds of resins, and laminating and fusion bonding these in the unstretched state or after stretching. From the viewpoint of ease of process, it is preferable to use a multilayer die and to laminate and fusion bond before curing.

[0056] In the present application, the base film can be a single layer as described above, or can be a multilayer (for example, two layers of two kinds, three layers of two kinds, three layers of three kinds, four layers, or more). From the viewpoint of being able to control the surface roughness of each single side, and being able to improve the processability such as winding properties, it is preferable to be a multilayer. More preferably, it is two layers of two kinds, three layers of two kinds, and further preferably, it is two layers of two kinds. Two layers of two kinds means two layers produced using two kinds of layer-forming materials, and the compositions (for example, particle content) of these two layers are different. Three layers of two kinds means three layers produced using two kinds of layer-forming materials, and the compositions (for example, particle content) of the 2 outermost layers and the middle layer are different. Three layers of three kinds means three layers produced using three kinds of layer-forming materials, and the compositions (for example, particle content) of these three layers are different from each other.

[0057] (Particle)

[0058] The base film can also contain particles for the purpose of imparting easy sliding properties and preventing the occurrence of scratches in each process. However, the base film constituting the laminated film of the present application needs to substantially not contain particles on the side of the laminated resin layer. The side of the base film on which the resin layer is formed substantially does not contain particles, and therefore the flatness of the resin layer surface on which the resin layer containing the specific acid-modified polyolefin resin (A) and the crosslinking agent (C) described later is formed is excellent. On the other hand, each layer of the base film other than the side on which the resin layer is formed can also contain particles within a range that does not impair the effects of the present application. Note that "substantially does not contain particles" means that the side of the base film on which the resin layer is formed is produced without adding particles. Therefore, the particle content of the side of the base film on which the resin layer is formed is particularly preferably zero, and can also contain 0.001% by mass or less within a range that does not impair the effects of the present application, and is further preferably contained to the extent of 0.0005% by mass or less.

[0059] The kind of the particles contained in the base film is not particularly limited as long as it is a particle that imparts slipperiness, and as specific examples, for example, inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, alumina, titanium oxide, and the like, organic particles such as acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin, benzoguanamine resin, and the like can be given. Furthermore, in the manufacturing process of the resin constituting the base, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst can be used.

[0060] In addition, the shape of the particles is not particularly limited, and can be any one of a spherical shape, a block shape, a rod shape, a flat shape, and the like.

[0061] The hardness, specific gravity, color, and the like of the particles are not particularly limited. Two or more kinds of particles can also be used as needed.

[0062] The average particle diameter of the particles is preferably 5 μm or less, and more preferably in the range of 0.01 to 3 μm. When the average particle diameter exceeds 5 μm, the surface roughness of the base film becomes too rough, and for example, in the case of use for transfer, there is a case where the surface shape of the molded surface to be transferred is affected.

[0063] The content of the particles in the base film is usually 5 mass% or less, and is preferably in the range of 0.0003 to 3 mass%. When the content of the particles exceeds 5 mass%, the film is sometimes easily broken in the stretching process at the time of manufacturing the laminated film of the present application.

[0064] The method of adding the particles is not particularly limited, and a method known in the art can be employed. For example, the addition can be performed at any stage of manufacturing the resin constituting each layer. In the case of the polyester manufacturing process, the addition can be preferably performed after the esterification or transesterification reaction is completed.

[0065] (Additives)

[0066] The base film can contain additives such as an antioxidant, a heat stabilizer, an ultraviolet absorber, an antistatic agent, a fixing agent (Japanese: pinning agent), and the like as needed. As the antioxidant, a hindered phenol compound, a hindered amine compound, and the like can be given, as the heat stabilizer, a phosphorus compound, and the like can be given, and as the ultraviolet absorber, a benzophenone compound, a benzotriazole compound, and the like can be given.

[0067] (Thickness)

[0068] The thickness of the base film is not particularly limited as long as it is in the range that a film can be made, and is usually 5 to 300 μm, and is preferably 10 to 150 μm from the viewpoints of mechanical strength, handleability, productivity, and the like.

[0069] <Resin Layer>

[0070] The laminated film of the present application is provided with a resin layer on at least one side of the layer of the base film described above which is substantially free of particles. From the viewpoint of imparting good mold releasability to the resin layer, the resin component constituting the resin layer needs to use an acid-modified polyolefin resin (A), and further contains a crosslinking agent (C). The resin layer can be formed by applying a resin layer-forming liquid which contains the acid-modified polyolefin resin (A), the crosslinking agent (C), and a compound (D) selected from at least one of amphiphilic oligomers, acetylenic diols, and oxirane adducts of acetylenic diols.

[0071] (Acid-modified polyolefin resin (A))

[0072] The acid-modified polyolefin resin is a resin obtained by modifying an olefin component as a main component with an acid-modifying component. The resin layer can also contain two or more acid-modified polyolefin resins (A).

[0073] The olefin component constituting the acid-modified polyolefin resin can use at least one selected from ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 1-nonene.

[0074] From the viewpoint of mold releasability with respect to an acrylic adhesive, the olefin component more preferably contains ethylene. From the viewpoint of further improving mold releasability with respect to an acrylic adhesive, the content of ethylene in the olefin component is preferably 50% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.

[0075] In addition, from the viewpoint of mold releasability with respect to an epoxy resin, the olefin component more preferably contains propylene. From the viewpoint of further improving mold releasability with respect to an epoxy resin, the content of propylene in the olefin component is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, further preferably 80% by mass or more, further preferably 90% by mass or more, and most preferably 95% by mass or more.

[0076] In addition, from the viewpoint of improving easy slip properties, the olefin component preferably contains an olefin component having a carbon number of 6 or more such as 1-hexene, 1-octene, and 1-nonene, and particularly preferably contains 1-octene. From the viewpoint of further improving easy slip properties, the content of 1-octene in the olefin component is preferably 15% by mass or more, and more preferably 25% by mass or more.

[0077] From the viewpoint of improving flatness as a problem to be solved by the present application, the content of 1-butene and 1-pentene in the olefin component constituting the acid-modified polyolefin resin is preferably 20% by mass or less of the polyolefin component, more preferably 15% by mass or less, further preferably 10% by mass or less, and particularly preferably contains no 1-butene or 1-pentene.

[0078] As the acid-modified component constituting the acid-modified polyolefin resin, an unsaturated carboxylic acid component can be given, and specifically, in addition to acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, and the like, a half ester, a half amide, and the like of an unsaturated dicarboxylic acid can be given. Among these, in order to stably disperse the resin in the water-based dispersion of the resin described later, acrylic acid, methacrylic acid, maleic acid, maleic anhydride are preferred, and acrylic acid, methacrylic acid, maleic anhydride are particularly preferred. Two or more of these acid-modified components can be contained in the acid-modified polyolefin resin.

[0079] The proportion of the acid-modified component in the acid-modified polyolefin resin is preferably 1 to 10% by mass, and more preferably 2 to 9% by mass. When the acid-modified component is less than 1% by mass, the proportion of the polar group in the acid-modified polyolefin resin contained in the resin layer becomes small, and thus the resin layer has a tendency that sufficient adhesion to the base film cannot be obtained, and sometimes the adherend released from the resin layer is contaminated. In addition, in the water-based dispersion of the resin described later, there is a tendency that the resin cannot be stably dispersed. On the other hand, when the proportion of the acid-modified component exceeds 10% by mass, the proportion of the polar group becomes large, and thus although the adhesion of the resin layer to the base film becomes sufficient, the adhesion of the resin layer to the adherend also becomes high at the same time, and thus there is a tendency that the releasability from the adherend is reduced.

[0080] In addition, for the purpose of further improving the adhesion to the base film, the acid-modified polyolefin resin can also contain an olefinically unsaturated component containing an oxygen atom in the side chain.

[0081] As the olefinically unsaturated component containing an oxygen atom in the side chain, an ester of (meth)acrylic acid and an alcohol having a carbon number of 1 to 30 can be given, and from the aspect of easiness of acquisition, an ester of (meth)acrylic acid and an alcohol having a carbon number of 1 to 20 is preferred. As specific examples of such a compound, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and the like can be given. A mixture thereof can also be used. Among these, from the aspect of adhesion to the polyester film, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl acrylate, octyl acrylate are more preferred, ethyl acrylate, butyl acrylate are further preferred, and ethyl acrylate is particularly preferred. "(Meth)acrylic acid" means "acrylic acid or methacrylic acid".

[0082] The olefinically unsaturated component containing an oxygen atom in the side chain has a polar group in the molecule as well as the acid-modified component. Therefore, by containing the olefinically unsaturated component containing an oxygen atom in the side chain in the acid-modified polyolefin resin, the adhesion of the resin layer to the base film becomes high. However, if the amount of the olefinically unsaturated component containing an oxygen atom in the side chain is too much, the properties of the resin derived from the olefin are lost, and there is a possibility that the releasability of the resin layer from the adherend is reduced. The proportion of the olefinically unsaturated component containing an oxygen atom in the side chain in the acid-modified polyolefin resin is preferably 1 to 40% by mass, more preferably 2 to 35% by mass, further preferably 3 to 30% by mass, and particularly preferably 6 to 18% by mass.

[0083] Note that even if the acid-modified polyolefin resin containing the olefinically unsaturated component containing an oxygen atom in the side chain is used, the releasability of the resin layer other than the adhesion to the base film is not impaired.

[0084] A small amount of other monomers can also be copolymerized in the acid-modified polyolefin resin. As the other monomers, for example, dienes, (meth)acrylonitrile, halogenated vinyls, halogenated vinylidene, carbon monoxide, sulfur dioxide, and the like can be given.

[0085] Each component constituting the acid-modified polyolefin resin can be copolymerized in the acid-modified polyolefin resin without limitation on the mode. As the state of copolymerization, for example, random copolymerization, block copolymerization, graft copolymerization (graft modification), and the like can be given.

[0086] The melting point of the acid-modified polyolefin resin is preferably 80 to 200°C, and more preferably 90 to 150°C. If the melting point of the acid-modified polyolefin resin exceeds 200°C, high-temperature treatment is sometimes required when the resin layer is formed on the surface of the base film. On the other hand, if the melting point of the acid-modified polyolefin resin is less than 80°C, the releasability of the resin layer is sometimes reduced.

[0087] As the acid-modified polyolefin resin that can be used in the present application, for example, the BONDINE series manufactured by Arkema Co., the NUCREL series manufactured by DUPONT-MITSUI POLYCHEMICALS Co., the REXPEARL series manufactured by Japan Polyethylene Co., the UMEX series manufactured by Sanyo Chemical Industries, Inc., the VESTOPLAST series manufactured by Evonik Co., the PRIMACOR series and the AFFINITY series manufactured by Dow Chemical Co., the ADMER series manufactured by Mitsui Chemicals, Inc., and the TOYOTAC series manufactured by Toyobo Co. can be given.

[0088] (Polyvinyl alcohol (B))

[0089] In the present application, the resin layer preferably contains polyvinyl alcohol from the viewpoint of improving the releasability. The polyvinyl alcohol is not particularly limited, and examples thereof include a substance obtained by completely or partially saponifying a polymer of a vinyl ester. By containing polyvinyl alcohol in the resin layer, the effect of improving the adhesion of the resin layer to the base material film and improving the releasability of the resin layer to the adherend can be exerted. The polyvinyl alcohol in the present application preferably has water solubility for the case of being used as a liquid as described later.

[0090] The degree of saponification of the polyvinyl alcohol is preferably 90% or more, and further preferably 93% or more from the viewpoint of the surface flatness of the resin layer and the releasability in a high-temperature region.

[0091] The content of the polyvinyl alcohol is preferably 10 to 1000 parts by mass, more preferably 100 to 1000 parts by mass, further preferably 210 to 800 parts by mass, and particularly preferably 300 to 600 parts by mass, with respect to 100 parts by mass of the above-described resin from the viewpoint of improving the releasability of the resin layer to the adherend and suppressing transfer to the adherend after peeling.

[0092] As the polyvinyl alcohol usable in the present application, for example, "JP-15" or "JT-05", "JL-05E", "JM-33", "JM-17", "JF-05", "VC-10" manufactured by JAPAN VAM & POVAL Co., Ltd., "PVA-CST", "PVA-624", "PVA-203", "PVA-220", "PVA-405" of "Kuraray POVAL" manufactured by Kuraray Co., Ltd., and the like can be given.

[0093] (Crosslinking agent (C))

[0094] In the present application, the resin layer needs to contain the above-described acid-modified polyolefin resin and the crosslinking agent from the viewpoint of imparting good releasability. By containing the crosslinking agent in the resin layer, the constituent components of the resin layer are crosslinked, the releasability is improved, the cohesiveness of the resin layer is improved, the resin layer is less likely to transfer to the adherend, and the water resistance is improved.

[0095] The content of the crosslinking agent is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and further preferably 2 to 10 parts by mass, with respect to 100 parts by mass of the above-described acid-modified polyolefin resin. If the content of the crosslinking agent is less than 1 part by mass, the cohesiveness of the resin layer becomes weak, the adhesion to the base material film is poor, and there is a tendency to easily transfer to the adherend. On the other hand, if it exceeds 20 parts by mass, a reaction sometimes occurs between the resin layer and the adherend, the releasability becomes poor, or the liquid used to form the resin layer sometimes increases in viscosity and the stability decreases.

[0096] As the cross-linking agent, a compound having multiple functional groups which react with the carboxyl group in the molecule, etc. can be used, and examples of which include a polyfunctional epoxy compound; a polyfunctional isocyanate compound; a polyfunctional aziridine compound; a compound containing a carbodiimide group; a compound containing an oxazoline group; a phenol resin; and an amino resin such as a urea compound, a melamine resin, a benzoguanamine resin, etc. One of these can be used, or two or more of these can be used in combination. Of these, a polyfunctional isocyanate compound, a melamine resin, a urea compound, a polyfunctional epoxy compound, a compound containing a carbodiimide group, a compound containing an oxazoline group, etc. are preferred, a compound containing a carbodiimide group, a compound containing an oxazoline group are more preferred, and a compound containing an oxazoline group is further preferred. By using a compound containing an oxazoline group, a laminate film which is excellent in releasability from the adherend and adhesion to the base film can be obtained. In addition, these cross-linking agents can also be used in combination.

[0097] As the polyfunctional epoxy compound, specifically a polyepoxy compound, a diepoxy compound, etc. can be used. As the polyepoxy compound, for example, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, tris(2-hydroxyethyl) isocyanurate triglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether can be used. As the diepoxy compound, for example, 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, polytetramethylene glycol diglycidyl ether can be used.

[0098] As the polyfunctional isocyanate compound, for example, toluene diisocyanate, diphenylmethane-4,4'-diisocyanate, m-xylylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanatohexane, an adduct of toluene diisocyanate with hexanetriol, an adduct of toluene diisocyanate with trimethylolpropane, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-bismethylphenyl-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, m-phenylene diisocyanate, etc. can be used. An end-capped isocyanate compound obtained by end-capping the isocyanate group with a bisulfite and a phenol, an alcohol, a lactam, an oxime, and an active methylene compound, etc. can also be used.

[0099] As the polyfunctional isocyanate compound, for example, toluene diisocyanate, diphenylmethane-4,4'-diisocyanate, m-xylylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanatohexane, an adduct of toluene diisocyanate with hexanetriol, an adduct of toluene diisocyanate with trimethylolpropane, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-bismethylphenyl-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, m-phenylene diisocyanate, etc. can be used. An end-capped isocyanate compound obtained by end-capping the isocyanate group with a bisulfite and a phenol, an alcohol, a lactam, an oxime, and an active methylene compound, etc. can also be used.

[0100] As the polyfunctional aziridine compound, for example, N,N'-hexamethylene-1, 6-bis-(1-aziridinylcarboxamide), trimethylolpropane-tris-β-aziridinylpropionate, or the like can be used.

[0101] As the compound having a carbodiimide group, there is no particular limitation as long as it has one or more carbodiimide groups in the molecule. The carbodiimide compound forms an ester with two carboxyl groups in the acid-modified portion of the acid-modified polyolefin resin in one carbodiimide moiety and achieves crosslinking. For example, a compound having a carbodiimide group such as p-phenylene-bis(2, 6-dimethylphenylcarbodiimide), tetramethylene-bis(tert-butylcarbodiimide), cyclohexane-1, 4-bis(methylene-tert-butylcarbodiimide), a polycarbodiimide as a polymer having a carbodiimide group, and the like can be used. One or two or more of these can be used. Among these, a polycarbodiimide is preferred from the viewpoint of ease of handling.

[0102] As commercially available products of the polycarbodiimide, Carbodilite series manufactured by Nippon Shokubai Co., Ltd. can be given, and specifically, "SV-02", "V-02", "V-02-L2", "V-04" of water-soluble type; "E-01", "E-02" of emulsion type; "V-01", "V-03", "V-07", "V-09" of organic solution type; "V-05" of solventless type can be given.

[0103] As for the compound containing an oxazoline group, there is no particular limitation as long as there are two or more oxazoline groups in the molecule. The oxazoline compound forms an amide ester with one carboxyl group in each of the two oxazoline moieties and the acid-modified moieties of the acid-modified polyolefin resin and achieves crosslinking. Such a polymer can be produced by homopolymerization of an addition-polymerizable monomer containing an oxazoline group, or polymerization with other monomers. Examples of the addition-polymerizable monomer containing an oxazoline group 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, 2-isopropenyl-5-ethyl-2-oxazoline, and the like. The addition-polymerizable monomer containing an oxazoline group can be used as one of them or a mixture of two or more of them. Among these, 2-isopropenyl-2-oxazoline is easily available industrially and is suitable. The other monomers are not limited as long as they are copolymerizable with the addition-polymerizable monomer containing an oxazoline group, and examples include alkyl acrylates, alkyl methacrylates (alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl), and the like (meth)acrylic acid esters; acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene sulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt, and the like), and the like unsaturated carboxylic acids; acrylonitrile, methacrylonitrile, and the like unsaturated nitriles; acrylamide, methacrylamide, N-alkyl acrylamide, N-alkyl methacrylamide, N,N-dialkyl acrylamide, N,N-dialkyl methacrylamide (alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, and the like), and the like unsaturated amides; vinyl acetate, vinyl propionate, and the like vinyl esters; methyl vinyl ether, ethyl vinyl ether, and the like vinyl ethers; ethylene, propylene, and the like α-olefins; chloroethylene, vinylidene chloride, fluoroethylene, and the like halogen-containing α,β-unsaturated aliphatic monomers; styrene, α-methylstyrene, and the like α,β-unsaturated aromatic monomers, and the like. The other monomers can be used as one of them or two or more of them. Among these, the polymer containing an oxazoline group is preferred from the viewpoint of ease of handling.

[0104] As commercially available products of the polymer containing an oxazoline group, the Epocros series manufactured by Japan Catalyst Co., Ltd. can be given, and specifically, "WS-500", "WS-700" of the water-soluble type; "K-1010E", "K-1020E", "K-1030E", "K-2010E", "K-2020E", "K-2030E", and the like of the emulsion type can be given.

[0105] As the phenol resin, for example, a resol type phenol formaldehyde resin and / or a novolac type phenol formaldehyde resin prepared using phenol or alkylphenol such as bisphenol A, p-t-butylphenol, octylphenol, p-cumylphenol, p-phenylphenol, cresol, or the like as a raw material can be used.

[0106] As the urea resin, for example, dimethylol urea, dimethylol ethylene urea, dimethylol propylene urea, tetramethylol acetylene urea, 4-methoxy-5-dimethylpropylene urea dimethylol can be used.

[0107] The melamine resin is, for example, a compound having imino group, methylol group, and / or alkoxy methyl group (e.g., methoxy methyl group, butoxy methyl group) as a functional group in one molecule. As the melamine resin, imino type methylated melamine resin, methylol type melamine resin, methylol type methylated melamine resin, fully alkyl type methylated melamine resin, or the like can be used. In order to promote the thermal curing of the melamine resin, it is preferable to use an acidic catalyst such as p-toluene sulfonic acid or the like.

[0108] As the benzoguanamine resin, for example, trihydroxymethyl benzoguanamine, hexahydroxymethyl benzoguanamine, trimethoxymethyl benzoguanamine, hexamethoxymethyl benzoguanamine, or the like can be used.

[0109] (Compound (D))

[0110] The resin layer in the present application can be formed using a liquid for forming a resin layer containing a resin component and the compound (D). By containing the compound (D) in the liquid for forming a resin layer and forming the resin layer in a specific method, flatness and easy slipperiness can be both achieved in the resin layer.

[0111] The compound (D) is at least one compound selected from amphiphilic oligomer, acetylene diol, and oxirane adduct of acetylene diol.

[0112] The amphiphilic oligomer refers to an oligomer having both a hydrophobic structure (also referred to as a hydrophobic segment) and a hydrophilic structure (also referred to as a hydrophilic segment) in a molecule.

[0113] The hydrophobic segment is not particularly limited, and for example, an alkyl group, an alkenyl group, an alkylphenyl group, a perfluoroalkyl group, a perfluoropolyether group, or the like can be mentioned. These can be contained alone, or can be a structure in which a plurality of these are combined.

[0114] The hydrophilic segment is not particularly limited, and for example, a polyoxyalkylene glycol such as polyethylene glycol, polypropylene glycol, or the like; a polyhydric alcohol such as glycerol, sorbitol, sorbitan, polyglycerol, fructose, sucrose, glucose, maltose, or the like can be mentioned.

[0115] As specific examples of the acetylenic diol, 2,5,8,11-tetramethyl-6-dodecyn-5,8-diol, 5,8-dimethyl-6-dodecyn-5,8-diol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol, 4,7-dimethyl-5-decyn-4,7-diol, 2,3,6,7-tetramethyl-4-octyn-3,6-diol, 3,6-dimethyl-4-octyn-3,6-diol, 3,6-diethyl-4-octyn-3,6-diol, 2,5-dimethyl-3-hexyn-2,5-diol, and the like can be given.

[0116] As specific examples of the acetylenic diol, 2,5,8,11-tetramethyl-6-dodecyn-5,8-diol, 5,8-dimethyl-6-dodecyn-5,8-diol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol, 4,7-dimethyl-5-decyn-4,7-diol, 2,3,6,7-tetramethyl-4-octyn-3,6-diol, 3,6-dimethyl-4-octyn-3,6-diol, 3,6-diethyl-4-octyn-3,6-diol, 2,5-dimethyl-3-hexyn-2,5-diol, and the like can be given.

[0117] The compound (D) is preferably a compound having a solubility of 0.05 g or more in 100 g of water at 20°C, or a compound that disperses when 0.1 g of the compound (D) is added to 100 g of water at 20°C and stirred. When the solubility of the compound (D) is less than 0.05 g or the compound does not disperse in water, the compound (D) cannot be mixed with the resin layer-forming liquid, and separation occurs with time, and not only is there a tendency for the stability of the resin layer-forming liquid to be poor, but also there is a tendency for the appearance of the resin layer to be impaired.

[0118] The content of the compound (D) in the resin layer-forming liquid is preferably 2 to 50 parts by mass, more preferably 3.5 to 30 parts by mass, and further preferably 5 to 25 parts by mass, relative to 100 parts by mass of the acid-modified polyolefin resin (A). If the content of the compound (D) in the resin layer-forming liquid is less than 2 parts by mass, there is a tendency for the resin layer surface to have a spread interface area ratio (Sdr) of 0.025 to 0.304% as measured by a non-contact surface shape measuring machine to be difficult to obtain. On the other hand, if the content of the compound (D) exceeds 50 parts by mass, the release properties of the resin layer are reduced or interference spots appear, the flatness is reduced, and there is a tendency for the maximum height (Sz) to not satisfy 0.01 to 0.50 μm.

[0119] Depending on the type, the compound (D) in the resin layer-forming liquid sometimes volatilizes due to heat treatment after being applied to the base film, and there is a tendency for the compound (D) not to remain in the resin layer formed.

[0120] In the present application, if a commercially available product that can be used as the compound (D) is exemplified, as the amphiphilic oligomer, Polyflow series "KL-900" manufactured by Kowa Company, Ltd. can be given, as the acetylene glycol, Olfine series "D-10" manufactured by Nippon Shokubai Co., Ltd. can be given, and as the oxirane adduct of acetylene glycol, Olfine series "E1004", "E1006", "E1010", or SURFYNOL series "420", "440", "485", and the like manufactured by Nippon Shokubai Co., Ltd. can be given.

[0121] In the present application, the resin layer can contain a lubricant within a range not impairing the effects of the present application. As the lubricant, for example, inorganic particles such as calcium carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, silicon oxide, sodium silicate, aluminum hydroxide, iron oxide, zirconium oxide, barium sulfate, titanium oxide, tin oxide, antimony trioxide, carbon black, and molybdenum disulfide; acrylic cross-linked polymers; styrene cross-linked polymers; silicone resins; fluorine resins; benzoguanamine resins; phenol resins; nylon resins; polyethylene waxes; organic particles such as the above; and surfactants can be given.

[0122] <Resin layer-forming liquid>

[0123] In the present application, the liquid medium that constitutes the resin layer-forming liquid containing the acid-modified polyolefin resin (A), the cross-linking agent (C), and the compound (D) is preferably an aqueous medium. The aqueous medium refers to a solvent containing water and an amphiphilic organic solvent, and the content of water is 2% by mass or more. The aqueous medium can be water alone.

[0124] The amphiphilic organic solvent refers to an organic solvent having a water solubility of 5% by mass or more with respect to the organic solvent at 20°C (with respect to the water solubility of the organic solvent at 20°C, for example, described in "Solvent Handbook" (Kodansha SCIENTIFIC, 10th edition, 1990) and the like).

[0125] As specific examples of the amphiphilic organic solvent, alcohols such as methanol, ethanol, n-propanol, and isopropanol; ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate, n-propyl acetate, isopropyl acetate, methyl propionate, and ethyl propionate; dimethyl carbonate; ethylene glycol derivatives such as ethylene glycol n-butyl ether; and organic amine compounds containing ammonia such as diethylamine, triethylamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine, and N,N-diethylethanolamine; lactams such as 2-pyrrolidone and N-methyl-2-pyrrolidone can be given.

[0126] The solid content concentration of the liquid for forming a resin layer can be appropriately selected depending on the lamination conditions, target thickness, properties, and the like, and is not particularly limited. However, in order to appropriately maintain the viscosity of the liquid and form a uniform resin layer, the solid content concentration is preferably 2 to 30% by mass, and more preferably 3 to 20% by mass.

[0127] In the liquid for forming a resin layer, an antioxidant, an ultraviolet absorber, a lubricant, a colorant, and the like can be added within a range not impairing the properties thereof.

[0128] <Manufacture of Laminated Film>

[0129] The manufacturing method of the laminated film of the present application includes a step of applying a liquid for forming a resin layer to a base film, and a step of drying and stretching the applied base film. In order to obtain a resin layer surface having the development interface area ratio (Sdr) defined in the present application, the liquid temperature at the time of applying the liquid for forming a resin layer must be 20 to 40°C, and preferably 25 to 35°C. If the liquid temperature at the time of applying the liquid for forming a resin layer is less than 20°C, the liquid is difficult to uniformly apply due to increased viscosity, and there is a case where the maximum height (Sz) of the resin layer surface becomes high. On the other hand, if the liquid temperature at the time of applying the liquid for forming a resin layer exceeds 40°C, the resin layer is likely to be subjected to bumping during drying, and there is a case where the development interface area ratio (Sdr) of the resin layer surface becomes high.

[0130] As a method of applying the liquid for forming a resin layer to a base film, known methods such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain coating, spray coating, dip coating, and brush coating can be mentioned. Among these, in order to be able to suppress the generation of coating streaks, gravure roll coating is particularly effective with respect to the liquid for forming a resin layer.

[0131] The manufacturing method of the laminated film of the present application includes a step of applying a liquid for forming a resin layer to a base film in the manufacturing step of the base film, and a step of drying and stretching the base film together. Further, a step of orientation stretching and heat fixation treatment is preferably included.

[0132] By applying the liquid for forming a resin layer in the manufacturing step of the base film, the resin layer can be formed in a state where the degree of orientation crystallization of the base film surface is low, and thus the adhesion of the base film to the resin layer is improved. Further, the resin layer can be heat treated at a higher temperature in a state where the base film is under tension, and thus the mold releasability and the residual adhesion can be improved without lowering the quality of the base film.

[0133] For the sake of simplicity and handling, a sequential biaxial stretching method is preferably employed, the liquid is applied to a base film stretched in a uniaxial direction, the base film to which the liquid is applied is dried, and then the base film is further stretched in a direction orthogonal to the above-mentioned direction and subjected to heat treatment.

[0134] <Properties of the resin layer>

[0135] The spreading interface area ratio (Sdr) of the resin layer surface, measured by a non-contact surface shape measuring machine, of the laminated film of the present application must be 0.025 to 0.304%, preferably 0.03 to 0.30%, and more preferably 0.04 to 0.25%, from the viewpoint of imparting easy slip properties and suppressing transfer to the adherend. If the spreading interface area ratio (Sdr) of the resin layer surface is less than 0.025%, the air layer contained in the resin layer surface is very small, and thus the easy slip properties become insufficient, causing problems in winding, unwinding, cutting, and the like during the film manufacturing process, and becoming a cause of scratches on the surface or damage to the appearance of the wound roll. In addition, if the spreading interface area ratio (Sdr) of the resin layer surface exceeds 0.304%, the unevenness of the resin layer surface becomes large, and the flatness is impaired, and thus it is difficult to satisfy the flatness required for small electronic devices and the like.

[0136] On the other hand, the spreading interface area ratio (Sdr) of the base film surface, measured by a non-contact surface shape measuring machine, without the resin layer is preferably 0.20% or more. If the spreading interface area ratio (Sdr) of the base film surface without the resin layer is less than 0.20%, the easy slip properties are reduced, and it is sometimes difficult to process the film when it is used for various processes.

[0137] In the present application, from the viewpoint of suppressing the transfer of surface properties to the adherend, the maximum height (Sz) of the surface roughness parameter of the surface of the resin layer constituting the laminated film must be 0.01 to 0.50 μm, preferably 0.01 to 0.40 μm, and more preferably 0.01 to 0.20 μm. By the surface roughness of the resin layer being in the above range, the resin layer is flattened, and the transfer of the coarse protrusions of the resin layer to the adherend is suppressed.

[0138] With respect to the laminated film of the present application, the peeling strength between the resin layer and the epoxy prepreg, measured when the epoxy prepreg is attached to the resin layer, is preferably 0.01 to 0.5 N / cm, more preferably 0.01 to 0.35 N / cm, and further preferably 0.01 to 0.15 N / cm. If the peeling strength exceeds 0.5 N / cm, it is heavy peeling, and it is difficult to practically use it as a release film.

[0139] With respect to the laminated film of the present application, the peeling strength between the resin layer and the adherend, measured when the acrylic adherend as the adhering material is attached to the resin layer, is preferably 3.0 N / cm or less, more preferably 2.8 N / cm or less, and further preferably 2.6 N / cm or less. If the peeling strength exceeds 3.0 N / cm, it is heavy peeling, and it is difficult to practically use it as a release film.

[0140] The thickness of the resin layer in the present application is preferably 0.01 to 1 μm, more preferably 0.03 to 0.7 μm, and further preferably 0.05 to 0.5 μm. If the thickness of the resin layer is less than 0.01 μm, sufficient mold releasability cannot be obtained, and if it exceeds 1 μm, it is easily transferred to the adherend, and the cost is increased, and thus it is not preferable.

[0141] Examples

[0142] The present application is specifically described below by way of examples, but the present application is not limited to these. The properties of the laminated film were measured by the following methods.

[0143] (1) Flatness (Spread area ratio (Sdr), Maximum height (Sz))

[0144] The spread area ratio (Sdr) and the maximum height (Sz) were measured for the resin layer surface using a non-contact surface shape measuring machine (VS1800 manufactured by Hitachi High-Tech Corporation) and in accordance with ISO 25178, and the spread area ratio (Sdr) was measured for the surface of the base material film on which the resin layer was not provided. The measurement was performed for 10 places for each surface, and the average value was used as the measurement result.

[0145] (Measurement conditions)

[0146] • Objective lens: 50 times

[0147] • Measurement area: 112 μm x 112 μm

[0148] • Measurement mode: WAVE

[0149] (Analysis conditions)

[0150] • Surface correction: 4 times

[0151] (2) Slippiness (Dynamic friction coefficient (μd))

[0152] The dynamic friction coefficient (μd) of the resin layer surface and the surface of the base material film on which the resin layer was not provided was obtained using a tensile testing machine (EZ-LX manufactured by Shimadzu Corporation) and in accordance with JIS K 7125, and was evaluated using the following criteria. The measurement was performed for 5 places, and the average value was used as the measurement result.

[0153] Good: 0.25 or more and less than 0.30

[0154] Good: 0.25 or more and less than 0.30

[0155] Good: 0.25 or more and less than 0.30

[0156] Good: 0.25 or more and less than 0.30

[0157] (3) Release property (peeling strength) from epoxy prepreg

[0158] A 60 mm x 100 mm-sized epoxy prepreg (EI-6765 manufactured by Sumitomo Bakelite Co., Ltd.) was sandwiched with the resin layer side of the obtained laminated film, and was heated at 15°C / min from 30°C to 150°C in a vacuum press machine at 1.07 kPa (8 Torr), and was further heated at 5°C / min from 150°C to 190°C, and was held at 190°C for 70 minutes while applying a pressure of 15 kg / cm 2 2 After that, the sample was cooled to room temperature, and thus a test sample was obtained.

[0159] The peeling strength of the obtained test sample after curing was measured in a constant temperature room at 23°C using a tensile testing machine (Autograph AGX-V manufactured by Shimadzu Corporation) at a peeling angle of 180 degrees and a peeling speed of 300 mm / min. The measurement was performed at five points, and the average value was used as the measurement result.

[0160] (4) Release property (peeling strength) from acrylic adhesive

[0161] An acrylic adhesive tape (No. 31B / acrylic adhesive manufactured by Nitto Electric Industrial Co., Ltd.) having a width of 50 mm and a length of 150 mm was pressure-bonded with a rubber roll on the resin layer side of the obtained laminated film, and thus a test sample was prepared. The test sample was sandwiched in the form of metal plate / rubber plate / test sample / rubber plate / metal plate, and was left in an atmosphere at 2 kPa load and 70°C for 20 hours, and after that, was cooled for 30 minutes or more to return to room temperature, and thus a test sample for peeling strength measurement was obtained.

[0162] The peeling strength of the acrylic adhesive tape and the laminated film of the test sample for peeling strength measurement was measured in a constant temperature room at 23°C using a tensile testing machine (Autograph AGX-V manufactured by Shimadzu Corporation) at a peeling angle of 180 degrees and a peeling speed of 300 mm / min. The measurement was performed at five points, and the average value was used as the measurement result.

[0163] (5) Transfer to adherend (maximum height (Sz) of the surface of the adherend after peeling)

[0164] ​An epoxy resin composition obtained by mixing 100 parts by mass of a bisphenol-type epoxy resin (jER828 manufactured by Mitsubishi Chemical Corporation), 50 parts by mass of an anhydride (MH-700 manufactured by Shin Nippon Rika Co., Ltd.) having 4-methylhexahydrophthalic anhydride as a main component, and 2 parts by mass of a curing accelerator (U-CAT18X manufactured by San Apro Co., Ltd.) was applied to the resin layer side of the obtained laminated film at a dried thickness of 20 μm using a wire bar, and dried at 160°C for 30 minutes to obtain a laminate on which the epoxy resin composition was laminated.

[0165] Subsequently, peeling was performed between the epoxy resin composition and the laminated film, and the maximum height (Sz) was measured on the resin layer side of the epoxy resin composition using the method described in the above "(1) flatness" and the average value was calculated.

[0166] Note that the maximum height (Sz) of the surface of the epoxy resin composition after peeling is preferably 0.40 μm or less, more preferably 0.30 μm or less, and further preferably 0.10 μm or less.

[0167] In order to prepare the liquid for forming the resin layer, an acid-modified polyolefin resin and an aqueous dispersion were produced by the following methods.

[0168] <Production of acid-modified polyolefin resin A-1>

[0169] After heating and melting 280 g of a propylene-ethylene copolymer (propylene / ethylene = 99 / 1 (mass ratio)) in a four-necked flask under a nitrogen atmosphere, the temperature in the system was maintained at 170°C and stirring was performed, and in this state, 32.0 g of maleic anhydride as an unsaturated carboxylic acid and 6.0 g of dicumyl peroxide as a radical initiator were added over a period of 1 hour each, and after that, the reaction was continued for 1 hour. After the completion of the reaction, the obtained reaction product was put into a large amount of acetone, and the resin was precipitated. The resin was further washed several times with acetone, and after removing the unreacted maleic anhydride, it was dried under reduced pressure in a reduced-pressure drier to obtain acid-modified polyolefin resin A-1 (acid modification amount 2.3%, melting point 145°C).

[0170] <Production of acid-modified polyolefin resin A-2>

[0171] In the production of the acid-modified polyolefin resin A-1 described above, the propylene-ethylene copolymer (propylene / ethylene = 99 / 1 (mass ratio)) was changed to an ethylene-ethyl acrylate copolymer (ethylene / ethyl acrylate = 93 / 7 (mass ratio)), and other than that, the same operations as in A-1 were performed to obtain acid-modified polyolefin resin A-2 (acid modification amount 2.0%, melting point 105°C).

[0172] <Production of acid-modified polyolefin resin A-3>

[0173] Ethylene-1-octene copolymer (ethylene / 1-octene = 61.9 / 38.1 (mass ratio)) 70 g, and maleic anhydride 14 g as an unsaturated carboxylic acid were dissolved in xylene 320.4 g in a four-necked flask under nitrogen atmosphere, the temperature of the system was maintained at 140°C and stirring was continued. Separately, dicumyl peroxide 4.2 g as a radical initiator, and xylene 15.6 g were put in another flask, and after forming a homogeneous solution, the system was replaced with nitrogen. To the xylene solution in which the above ethylene-octene copolymer and maleic anhydride were dissolved, the xylene solution of dicumyl peroxide was added over 30 minutes, and the temperature of the system was maintained at 140°C under nitrogen atmosphere and stirring was continued for 5 hours. Thereafter, the solution in the four-necked flask was cooled to 50°C and the whole amount was put into a large amount of methanol to precipitate the resin. The resin was further washed several times with acetone to remove unreacted maleic anhydride, and dried under reduced pressure in a reduced-pressure drier to obtain an acid-modified polyolefin resin A-3 (acid-modification amount 2.2%).

[0174] <Manufacture of acid-modified polyolefin resin A-4>

[0175] In the manufacture of the above acid-modified polyolefin resin A-1, propylene-ethylene copolymer (propylene / ethylene = 99 / 1 (mass ratio)) was changed to propylene / 1-butene / ethylene terpolymer (propylene / 1-butene / ethylene = 64.8 / 23.9 / 11.3 (mass ratio)), and otherwise the same operation as A-1 was performed to obtain an acid-modified polyolefin resin A-4 (acid-modification amount 6.3%, melting point 135°C).

[0176] The composition of the obtained acid-modified polyolefin resins A-1 to A-4 is shown in Table 1.

[0177] [Table 1]

[0178]

[0179] <Manufacture of aqueous dispersion of acid-modified polyolefin resin A-1>

[0180] Using a stirrer equipped with a heater and a closable pressure-resistant 1 L-capacity glass container, 60.0 g of the acid-modified polyolefin resin A-1 produced by the above method, 45.0 g of ethylene glycol n-butyl ether (boiling point 171°C), 6.9 g of N,N-dimethylethanolamine (boiling point 134°C, 1.0 equivalent of carboxyl group with respect to the maleic anhydride unit in the resin), and 188.1 g of distilled water were put into the glass container, and stirring was performed with the rotation speed of the stirring blade set to 300 rpm. At this time, no precipitation of the resin was found in the bottom of the container, and it was confirmed that the resin was in a floating state. After 10 minutes in this state, the power of the heater was turned on and heating was performed. Then, the temperature in the system was maintained at 140°C and further stirring was performed for 60 minutes. Thereafter, air cooling was performed, and the stirring was performed at a rotation speed of 300 rpm and the system was cooled to room temperature (about 25°C). Further, a uniform aqueous dispersion of the acid-modified polyolefin resin A-1 (solid content concentration 25 mass%) was obtained by pressure filtration (air pressure 0.2 MPa) using a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave). Note that almost no resin remained on the filter.

[0181] <Manufacture of an aqueous dispersion of acid-modified polyolefin resin A-2>

[0182] The acid-modified polyolefin resin used was changed to A-2, and otherwise, an aqueous dispersion of acid-modified polyolefin resin A-2 (solid content concentration 25 mass%) was obtained by the same method as the method of dispersing A-1.

[0183] <Manufacture of an aqueous dispersion of acid-modified polyolefin resin A-3>

[0184] Using a stirrer equipped with a 1 L capacity glass container capable of being closed and resistant to pressure, and a heater, 30.0 g of the acid-modified polyolefin resin A-3, 90.0 g of tetrahydrofuran, 15.0 g of triethylamine, 2.4 g of 2-dimethylaminoethanol, and 165.0 g of distilled water, which were manufactured by the above method, were put into the glass container, and the stirring blade was rotated at 300 rpm. This state was maintained, and after 10 minutes, the power of the heater was turned on to start heating. Next, the temperature of the system was maintained at 120°C and further stirred for 60 minutes. Thereafter, while stirring, air cooling was performed to cool to room temperature (about 25°C), and the entire amount of the obtained dispersion was moved to a 1 L flask. While being immersed in a hot water bath heated to 60°C, the solvent was removed by evaporation under reduced pressure using an evaporator, and 74 g of the aqueous medium was distilled off. Next, after 93.6 g of distilled water was added to the dispersion in the flask, while being immersed in a hot water bath heated to 60°C, the solvent was removed by evaporation under reduced pressure using an evaporator, and 82 g of the aqueous medium was distilled off. After cooling, the dispersion in the flask was filtered under pressure using a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) (air pressure 0.2 MPa), and a uniform aqueous dispersion of the acid-modified polyolefin resin A-3 (solid content concentration 12.5 mass%) was obtained.

[0185] <Manufacture of an aqueous dispersion of an acid-modified polyolefin resin A-4>

[0186] The acid-modified polyolefin resin used was changed to A-4, and otherwise, by the same method as the method of dispersing A-1, an aqueous dispersion of the acid-modified polyolefin resin A-4 (solid content concentration 25 mass%) was obtained.

[0187] In order to prepare the liquid for forming a resin layer, the polyvinyl alcohol (B) was used as the following aqueous solution.

[0188] B-1: JT-05 manufactured by JAPAN VAM & POVAL Co., Ltd., saponification rate 94.5%, degree of polymerization 500, solid content concentration 8.0%

[0189] B-2: VC-10 manufactured by JAPAN VAM & POVAL Co., Ltd., saponification rate 99.3%, degree of polymerization 1000, solid content concentration 8.0%

[0190] The crosslinking agent (C) was used as the following compound.

[0191] C-1: Compound containing oxazoline group (Epocros WS-700 manufactured by Showa Denko K.K., solid content concentration 25 mass%)

[0192] C-2: Compound containing carbodiimide group (Carbodilite V-02-L2 manufactured by Nippon Shokubai Co., Ltd., solid content concentration 40 mass%)

[0193] Compound (D) is used as follows.

[0194] D-1: Amphiphilic oligomer (Polyflow KL-900 manufactured by Kyoeisha Chemical Co., Ltd.)

[0195] D-2: Acetylenic diol (Olfine D-10 manufactured by Nippon Shinyaku Co., Ltd.)

[0196] D-3: Acetylenic diol-based oxirane adduct (Olfine E1010 manufactured by Nippon Shinyaku Co., Ltd.)

[0197] D-4: Modified silicone (Polyflow KL-401 manufactured by Kyoeisha Chemical Co., Ltd.)

[0198] Polyethylene terephthalate constituting a base film was produced by the following method.

[0199] < Polyethylene terephthalate P-1 >

[0200] Polymerization of terephthalic acid and ethylene glycol was performed by a conventional method using an antimony oxide catalyst to obtain a substantially particle-free melt-polymerized polyethylene terephthalate P-1.

[0201] < Polyethylene terephthalate P-2 >

[0202] During the polymerization of P-1 described above, 0.08 mass% of silica particles having an average particle diameter of 2.3 μm were added with respect to the polyethylene terephthalate to obtain a melt-polymerized polyethylene terephthalate P-2.

[0203] Example 1

[0204] < Preparation of liquid for resin layer formation >

[0205] An acid-modified polyolefin resin A-1 aqueous dispersion, a polyvinyl alcohol aqueous solution B-1, an aqueous solution C-1 of a compound containing an oxazoline group as a crosslinking agent, and a compound D-1 were mixed so that the solid content would be 100 mass parts, 300 mass parts, 5 mass parts, and 20 mass parts, respectively, and adjusted with water so that the final solid content concentration would be 7 mass%, to obtain a liquid for resin layer formation.

[0206] < Production of laminated film >

[0207] Polyethylene terephthalate P-1 was fed to an extruder 1 (screw diameter: 50 mm), and polyethylene terephthalate P-2 was fed to an extruder 2 (screw diameter: 65 mm), and after melting at 280°C, the respective melts were co-flowed and laminated in 2 layers in such a manner that the thickness ratio of the layers (P layer containing P-1 / S layer containing P-2) became 33 / 5 and the total thickness became 600 μm before reaching the outlet of the T die of the multi-layer die. The laminated melt was extruded from the T die outlet of the multi-layer die, and was adhered to a casting drum and quenched by the T die method - electrostatic fixation method, and an unstretched film having a thickness of 600 μm was formed.

[0208] Next, the unstretched film was stretched 3.5 times with a longitudinal stretching roll heated to 90°C.

[0209] On one side of the longitudinally stretched film (the side of the P layer containing polyethylene terephthalate P-1), a resin layer-forming liquid at a liquid temperature of 30°C was applied in an amount of 10 g / m 2 (WET conversion) using a reverse gravure coater, and the longitudinally stretched film on which the resin layer-forming liquid was applied was dried and stretched 4.5 times in a transverse stretching tenter at 120°C, and after heat treatment at 230°C for 10 seconds, it was cooled and wound. The thickness of the obtained laminated film was 38 μm, and the thickness of the resin layer was about 0.10 μm. Note that the development interface area ratio (Sdr) of the substrate film side on which the resin layer was not provided was 0.33.

[0210] Examples 2 to 19, Comparative Examples 2 to 4, 6 to 8, 10, 12

[0211] The layer constitution of the substrate film, and the constitution and liquid temperature at the time of application of the resin layer-forming liquid were changed as shown in Table 2, and otherwise, the same operations as in Example 1 were performed, and a laminated film was obtained.

[0212] Comparative Example 1

[0213] Polyethylene terephthalate P-1 was fed to an extruder 1 (screw diameter: 50 mm), and polyethylene terephthalate P-2 was fed to an extruder 2 (screw diameter: 65 mm), and after melting at 280°C, the respective melts were co-flowed and laminated in 3 layers in such a manner that the thickness ratio of the layers (S layer containing P-2 / P layer containing P-1 / S layer containing P-2) became 5 / 28 / 5 and the total thickness became 600 μm before reaching the outlet of the T die of the multi-layer die. The laminated melt was extruded from the T die outlet of the multi-layer die, and was adhered to a casting drum and quenched by the T die method - electrostatic fixation method, and an unstretched film having a thickness of 600 μm was formed.

[0214] Next, the unstretched film was stretched 3.5 times with a longitudinal stretching roll heated to 90°C.

[0215] Next, a resin layer-forming liquid was applied to one side of the longitudinally stretched film, and otherwise the same operation as in Example 1 was performed to obtain a laminated film.

[0216] Comparative Examples 5, 9, and 11

[0217] The composition of the resin layer-forming liquid was changed as in Tables 2 to 4, and otherwise the same operation as in Comparative Example 1 was performed to obtain a laminated film.

[0218] The laminated films obtained in the Examples and Comparative Examples were evaluated in various ways, and the results obtained are shown in Tables 2 to 4.

[0219] [Table 2]

[0220]

[0221] [Table 3]

[0222]

[0223] [Table 4]

[0224]

[0225] The spread interface area ratio (Sdr) and the maximum height (Sz) of the resin layer of the laminated films of Examples 1 to 19 were values within the ranges specified in the present application, and a good winding roll with excellent easy slip properties and a flat surface shape with good release properties were obtained.

[0226] The resin layer of the laminated films of Comparative Examples 1, 5, 9, and 11 was formed on the S layer of the base film of the multilayer structure, which contained particles, and thus the maximum height (Sz) was outside the range specified in the present application, the flatness was poor, and the maximum height (Sz) of the adherend surface after peeling was also high.

[0227] The resin layer of the laminated films of Comparative Examples 2, 3, and 10 was formed on the P layer of the base film of the multilayer structure, which did not contain particles, and the maximum height (Sz) was within the range specified in the present application, and the flatness was excellent, but the resin layer-forming liquid did not contain compound (D) or contained a small amount of compound (D), and thus the spread interface area ratio (Sdr) was outside the range specified in the present application, and the easy slip properties were poor.

[0228] The Sdr and Sz of the resin layer of the laminated films of the other Comparative Examples were outside the ranges specified in the present application, and thus the easy slip properties and the flatness were poor.

Claims

1. A laminated film, characterized in that, It is a laminated film in which a resin layer is provided on at least one side of a substrate film. The substrate film surface with the resin layer does not actually contain particles. The resin layer contains acid-modified polyolefin resin A and crosslinking agent C. The unfolded interfacial area ratio (Sdr) of the resin layer, determined by a non-contact surface shape measuring machine, is 0.025% to 0.304%, and the maximum height (Sz) is 0.01 μm to 0.50 μm.

2. The laminated film according to claim 1, characterized in that, The olefin component of acid-modified polyolefin resin A contains propylene or 1-octene.

3. The laminated film according to claim 2, characterized in that, The propylene content in the olefin component is above 70% by mass.

4. The laminated film according to claim 2, characterized in that, The olefin component contains 15% or more of 1-octene by mass.

5. The laminated film according to any one of claims 1 to 4, characterized in that, The peel strength between the resin layer and the epoxy prepreg is below 0.5 N / cm.

6. A method for manufacturing a laminated film, characterized in that, It is a method for manufacturing the laminated film according to any one of claims 1 to 5, the method comprising: In the process of forming a liquid resin layer at a substrate film coating temperature of 20–40°C, the liquid resin layer forming liquid contains an acid-modified polyolefin resin A, a crosslinking agent C, and a compound D selected from at least one of amphiphilic oligomers, acetylenic diol, and ethylene oxide adducts of acetylenic diol; and The process of drying and stretching a substrate film coated with a liquid for forming a resin layer.

7. The method for manufacturing a laminated film according to claim 6, characterized in that, A resin layer forming liquid containing 2 to 50 parts by mass of compound D relative to 100 parts by mass of acid-modified polyolefin resin A is applied.

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