Release film coating agent, release film, laminate, and article

Abstract

To provide a coating agent for a release film capable of easily and satisfactorily forming an uneven shape, and the like.SOLUTION: The coating agent for a release film contains a polyfunctional (meth)acrylate, a monofunctional (meth)acrylate having a C12 or higher alkyl group, a perfluoropolyether compound having a number average molecular weight of 4,000 or more and having a (meth)acryloyl group, and a solvent. The contents of the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate are in a mass ratio (polyfunctional (meth)acrylate:monofunctional (meth)acrylate) of 1:1.0-1:3.0.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a coating agent for a release film, a release film, a laminate, and an article.

Background Art

[0002] Conventionally, release films have been widely used as protective films for resin layers such as adhesive films, adhesive sheets, and adhesive tapes, process films for manufacturing electronic components such as ceramic green sheets and printed circuit boards, and process films for casting films such as urethane resins, acrylic resins, and vinyl chloride resins. A release film has a release layer on at least one of its substrates and is used for the purpose of molding or protecting an adhesive surface, an adhesive surface, or a resin layer.

[0003] There is a technique of providing an uneven shape on the surface of such a release film and transferring the uneven shape to the surface of the object to which the release film is applied. Transfer means that, for example, by laminating the object to be used on the side having the uneven shape of the release film, the uneven shape of the release film is reflected on the surface of the object to be used, and an uneven shape in which the unevenness of the release film is inverted is formed on the surface of the object to be used. For example, by forming an uneven shape on the surface of an adhesive film, the air permeability and designability of the adhesive film are improved. Further, by forming an uneven shape on the surface of a resin molded product, the designability and visibility of the resin molded product are improved.

[0004] For example, Patent Document 1 discloses a release liner having a fine embossed pattern composed of a large number of linearly raised portions connected to each other on one surface, and an article including the release liner and a pressure-sensitive adhesive layer laminated on the surface thereof.

[0005] Patent Document 2 discloses a process paper for synthetic leather including a release agent layer formed on a substrate, wherein the release agent layer contains amorphous particles, and thus an uneven shape is provided on the surface of the process paper.

Prior Art Documents

Patent Documents

[0006] Japanese Patent Document 1 Japanese Unexamined Patent Application Publication No. 2006-70273 Japanese Patent Document 2 Japanese Unexamined Patent Application Publication No. 2021-11648 Summary of the Invention Problems to be Solved by the Invention

[0007] In Patent Document 1, there is a problem that the man-hour increases because the uneven shape is formed by embossing, and it is necessary to prepare a dedicated mold. In Patent Document 2, there are problems that contamination of the adherend due to particle detachment occurs and it is difficult to form a uniform uneven shape.

[0008] The present invention has been made in view of the above-described current state of the prior art, and its main object is to provide a coating agent for a release film or the like that can easily and favorably form an uneven shape. Means for Solving the Problems

[0009] The present inventor has intensively studied to solve the above problems. As a result, it has been found that a coating agent for a release film can easily and favorably form an uneven shape by containing a specific polyfunctional (meth)acrylate, a monofunctional (meth)acrylate, a perfluoropolyether compound, and a solvent. The present invention has been completed based on such findings.

[0010] That is, the coating agent for a release film according to one aspect of the present invention contains a polyfunctional (meth)acrylate, a monofunctional (meth)acrylate having an alkyl group having 12 or more carbon atoms, a perfluoropolyether compound having a number average molecular weight of 4000 or more and having a (meth)acryloyl group, and a solvent, and the content of the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate is 1:1.0 to 1:3.0 in terms of mass ratio (polyfunctional (meth)acrylate: monofunctional (meth)acrylate).

[0011] The release film according to one aspect of the present invention is a release film including a base material and a release layer formed on at least one surface of the base material, wherein the release layer contains a polyfunctional (meth)acrylate, a monofunctional (meth)acrylate having an alkyl group with 12 or more carbon atoms, and a perfluoropolyether compound having a number average molecular weight of 4000 or more and having a (meth)acryloyl group, and the content of the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate is 1:1.0 to 1:3.0 in terms of mass ratio (polyfunctional (meth)acrylate: monofunctional (meth)acrylate).

[0012] The release film according to one aspect of the present invention is a release film including a base material and a release layer formed on at least one surface of the base material, wherein the release layer includes a first layer formed on the base material and containing a polyfunctional (meth)acrylate, a second layer formed on the first layer and containing a perfluoropolyether compound, and a third layer formed in an island shape on the second layer and containing a monofunctional (meth)acrylate.

[0013] The laminate according to one aspect of the present invention includes any one of the above-described release films and a resin layer laminated on the release film.

[0014] The laminate according to one aspect of the present invention includes any one of the above-described release films and a resin layer laminated on the release film, and the uneven shape on the surface of the resin layer is formed by transferring the uneven shape on the surface of the release layer in the release film.

[0015] The article according to one aspect of the present invention has any one of the above-described release films.

Effects of the Invention

[0016] According to the present invention, it is possible to provide a coating agent for a release film or the like that can easily and favorably form an uneven shape.

Brief Description of the Drawings

[0017]

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Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described in detail.

[0019] In this specification, the "(meth)acryloyl group" is a general term for the "acryloyl group" and the "methacryloyl group", and the "(meth)acrylate" is a general term for the "acrylate" and the "methacrylate".

[0020] (Coating Agent for Release Film) The coating agent for a release film according to the embodiment contains a polyfunctional (meth)acrylate, a monofunctional (meth)acrylate having an alkyl group with 12 or more carbon atoms, a perfluoropolyether compound having a number average molecular weight of 4000 or more and a (meth)acryloyl group, and a solvent. Due to the coexistence of these, an uneven shape can be easily and favorably formed on the surface of the release layer formed using the coating agent for a release film, and the releasability (peelability) of the release film is excellent.

[0021] The polyfunctional (meth)acrylate used in the coating agent for a release film according to the embodiment has a function of polymerizing by irradiation with active energy rays and undergoing a crosslinking reaction. The polyfunctional (meth)acrylate is not particularly limited as long as it is a compound containing two or more (meth)acryloyl groups. From the viewpoint of curability by active energy rays, the polyfunctional (meth)acrylate preferably has three or more functional groups. From the viewpoint of favorably forming an uneven shape, the polyfunctional (meth)acrylate is preferably a monomer having a molecular weight of 1000 or less.

[0022] Examples of the bifunctional (meth)acrylate include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene polypropylene glycol di(meth)acrylate, and the like. Examples of the trifunctional (meth)acrylate include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and the like. Examples of the tetrafunctional or higher (meth)acrylate include pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol poly(meth)acrylate, and the like. Among polyfunctional (meth)acrylates, pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate are particularly preferred. The polyfunctional (meth)acrylate may be used alone or in combination of two or more. When two or more are combined, a combination of pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate is preferred. Examples of commercially available polyfunctional (meth)acrylates include "Aronix M-306" (manufactured by Toagosei Co., Ltd.).

[0023] The content of the polyfunctional (meth)acrylate is preferably 20% by mass or more and 45% by mass or less in the solid content of the release film coating agent. When two or more are used in combination, the content means the total amount. In this specification, "in the solid content of the release film coating agent" means in the total amount of all solid contents contained in the release film coating agent of the embodiment. In this case, the uneven shape described later can be formed well, the releasability can be enhanced, and the liquid stability can be improved. The content of the polyfunctional (meth)acrylate is more preferably 25% by mass or more, still more preferably 30% by mass or more, and more preferably 40% by mass or less.

[0024] The monofunctional (meth)acrylate used in the release film coating agent of the embodiment has an alkyl group having 12 or more carbon atoms. Since the monofunctional (meth)acrylate has a long-chain alkyl group having 12 or more carbon atoms, the uneven shape can be formed well and the releasability can be enhanced. The alkyl group of the monofunctional (meth)acrylate is preferably 12 to 22 carbon atoms, more preferably 12 to 18 carbon atoms, and still more preferably 12 carbon atoms from the viewpoints of availability and cost reduction.

[0025] The coating agent for the release film of the embodiment contains a polyfunctional (meth)acrylate, which is an incompatible compound, and a monofunctional (meth)acrylate, so that the two are separated in a solvent, and an uneven shape is easily and favorably expressed. From the viewpoint of favorably forming the uneven shape, the alkyl group of the monofunctional (meth)acrylate is preferably linear or branched, and more preferably linear. The monofunctional (meth)acrylate is preferably a monomer having a molecular weight of 500 or less from the viewpoint of favorably forming the uneven shape.

[0026] Examples of the monofunctional (meth)acrylate include lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, eicosyl (meth)acrylate, behenyl (meth)acrylate, isobornyl (meth)acrylate, and the like. Among them, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, and behenyl (meth)acrylate are preferable. The monofunctional (meth)acrylate may be used alone or in combination of two or more. Examples of commercially available monofunctional (meth)acrylates include "Light Ester L" (manufactured by Kyoeisha Chemical Co., Ltd.), "STA" (manufactured by Osaka Organic Chemical Industry Co., Ltd.), "Light Ester S" (manufactured by Eisha Chemical Co., Ltd.), "Blemmer VA" (manufactured by NOF Corporation), and the like.

[0027] The content of the monofunctional (meth)acrylate is preferably 40% by mass or more and 60% by mass or less in the solid content of the coating agent for the release film. When two or more are used in combination, the content means the total amount. In this case, the uneven shape described later can be favorably formed, the releasability can be enhanced, and the liquid stability can be improved. The content of the monofunctional (meth)acrylate is more preferably 44% by mass or more, and more preferably 56% by mass or less.

[0028] The content ratio of the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate is in a mass ratio (polyfunctional (meth)acrylate: monofunctional (meth)acrylate) of 1:1.0 to 1:3.0. If the mass ratio is within the above ratio range, the synergistic effect due to the coexistence of both can be significantly manifested, the concavo-convex shape can be formed well, and the liquid stability can be improved. The mass ratio of the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate is preferably 1:1.0 to 1:2.5, more preferably 1:1.0 to 1:2.0, still more preferably 1:1.1 to 1:2.0, and most preferably 1:1.1 to 1:1.5.

[0029] The perfluoropolyether compound used in the coating agent for the release film of the embodiment is a compound having a perfluoropolyether group represented by the following general formula (1). The perfluoropolyether compound improves the releasability (peelability).

[0030]

Chemical formula

[0031] The number average molecular weight (Mn) of the perfluoropolyether compound used in the coating agent for the release film of the embodiment is 4000 or more. When the number average molecular weight (Mn) of the perfluoropolyether compound is 4000 or more, the synergistic effect due to the coexistence of the perfluoropolyether compound, the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate can be significantly manifested, the concavo-convex shape can be formed well, and the releasability can be improved. From the viewpoint of improving the releasability, the number average molecular weight (Mn) of the perfluoropolyether compound is preferably 6000 or more. The perfluoropolyether compound may be used alone or in combination of two or more. The number average molecular weight (Mn) is a value measured using the nuclear magnetic resonance (NMR) method.

[0032] The perfluoropolyether compound used in the coating agent for the release film of the embodiment has a (meth)acryloyl group at at least one end as a functional group. From the viewpoint of improving releasability, curability, and heat resistance, a urethane (meth)acryloyl group having a urethane bond is preferable as the (meth)acryloyl group.

[0033] The perfluoropolyether compound having urethane (meth)acrylate can be synthesized by a known method. As an example, it can be obtained by adding an isocyanate compound to a hydroxyl group-containing perfluoropolyether compound in the presence of a suitable urethanization catalyst.

[0034] Examples of commercially available hydroxyl group-containing perfluoropolyether compounds include "FLUOROLINK D-6000" (manufactured by Solvay Specialty Polymers Japan Ltd.) and "FLUOROLINK ZMF-402" (manufactured by Solvay Specialty Polymers Japan Ltd.).

[0035] Examples of the isocyanate compound include 2-acryloyloxyethyl isocyanate and 1,1-bisacryloyloxymethylethyl isocyanate. Among them, 1,1-bisacryloyloxymethylethyl isocyanate is preferable. Examples of commercially available isocyanate compounds include "KARENZ BEI" (manufactured by Showa Denko K.K.) and "KARENZ AOI" (manufactured by Showa Denko K.K.).

[0036] The content of the perfluoropolyether compound is preferably 0.5% by mass or more and 20% by mass or less in the solid content of the coating agent for the release film. When two or more are used in combination, the content means the total amount. In this case, an uneven shape can be formed well and the releasability can be improved. The content of the perfluoropolyether compound is more preferably 1% by mass or more, and more preferably 10% by mass or less, still more preferably 5% by mass or less.

[0037] The content of the perfluoropolyether compound and the polyfunctional (meth)acrylate is preferably in a mass ratio (perfluoropolyether compound: polyfunctional (meth)acrylate) of 1:20 to 1:45. If the mass ratio is within the above ratio range, the synergistic effect due to their coexistence can be significantly manifested, the uneven shape can be formed well, and the releasability can be improved. The content of the perfluoropolyether compound and the polyfunctional (meth)acrylate is more preferably 1:25 to 1:45, still more preferably 1:25 to 1:40, and most preferably 1:25 to 1:38.

[0038] The content of the perfluoropolyether compound and the monofunctional (meth)acrylate is preferably in a mass ratio (perfluoropolyether compound: monofunctional (meth)acrylate) of 1:30 to 1:60. If the mass ratio is within the above ratio range, the synergistic effect due to their coexistence can be significantly manifested, the uneven shape can be formed well, and the releasability can be improved. The content of the perfluoropolyether compound and the monofunctional (meth)acrylate is more preferably 1:30 to 1:55, still more preferably 1:35 to 1:55, and most preferably 1:40 to 1:55.

[0039] The coating agent for the release film of the embodiment contains a solvent. After dissolving the above components in the solvent and then removing the solvent, an uneven shape can be formed well.

[0040] Examples of the solvent include ketone solvents (such as acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), hydrocarbon solvents (such as benzene, toluene, etc.), ether solvents (such as diethyl ether, tetrahydrofuran, etc.), alcohol solvents (such as methanol, ethanol, propanol, isopropanol, etc.), ester solvents (such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methoxybutyl acetate, methoxypropyl acetate, etc.), fluorine solvents (such as hydrofluoroether, etc.). From the viewpoint of enhancing the solubility of each of the above components, ketone solvents are preferred, and methyl ethyl ketone is more preferred. The solvent may be used alone or in combination of two or more kinds.

[0041] The content of the solvent is not particularly limited. For example, it can be appropriately adjusted so that the solid content in the coating agent for the release film is in the range of about 0.1% by mass or more and 90% by mass or less, preferably 1% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 30% by mass or less.

[0042] The coating agent for the release film of the embodiment preferably contains a polymer having a lower number average molecular weight than the perfluoropolyether compound having a number average molecular weight of 4000 or more. By mixing and using a plurality of polymers having different average molecular weights, a perfluoropolyether compound having a high number average molecular weight of 4000 or more can be dissolved or dispersed well in the solvent. Thereby, various solvents such as solvents other than highly volatile fluorine solvents can be preferably used. The polymer having a lower number average molecular weight may be used alone or in combination of two or more kinds.

[0043] The number average molecular weight (Mn) of a polymer with a lower number average molecular weight than that of a perfluoropolyether compound having a number average molecular weight of 4000 or more (hereinafter also referred to as a high molecular weight perfluoropolyether compound) is preferably 500 or more and less than 4000. When the number average molecular weight of the low molecular weight polymer is within the above range, the compatibility between the low molecular weight polymer and the high molecular weight perfluoropolyether compound is enhanced, and the solubility of the low molecular weight polymer and the high molecular weight perfluoropolyether compound in a solvent becomes good.

[0044] As the low molecular weight polymer, a perfluoropolyether compound is preferred. By using in combination a plurality of types of perfluoropolyether compounds having different average molecular weights, the coating agent for the release film has good dissolution performance in a solvent and realizes excellent release performance.

[0045] The perfluoropolyether compound as the low molecular weight polymer preferably has a (meth)acryloyl group at at least one end as a functional group, more preferably has a urethane (meth)acryloyl group having a urethane skeleton at at least one end, and even more preferably has urethane (meth)acryloyl groups at both ends. Examples of commercially available products of such perfluoropolyether compounds include "FLUOROLINK (registered trademark) AD-1700" (manufactured by Solvay Specialty Polymers Japan Co., Ltd.).

[0046] The content of the low molecular weight polymer is not limited, but is preferably 1.0% by mass or more and 3.0% by mass or less in the solid content of the coating agent for the release film. The content in the case of using two or more in combination means the total amount. In this case, the solubility can be improved and the coating agent for the release film can be easily prepared. From the viewpoint of improving solubility, the content of the low molecular weight polymer is more preferably 1.5% by mass or more, and from the viewpoint of improving release properties, it is more preferably 2.5% by mass or less.

[0047] When the coating agent for a release film contains a high molecular weight perfluoropolyether compound and a low molecular weight polymer, the content of the high molecular weight perfluoropolyether compound is preferably 10 parts by mass or more and 50 parts by mass or less, more preferably 25 parts by mass or more and 50 parts by mass or less, still more preferably 25 parts by mass or more and 45 parts by mass or less, based on 100 parts by mass of the total amount of the high molecular weight perfluoropolyether compound and the low molecular weight polymer with respect to the total solid content. When the content of the high molecular weight perfluoropolyether compound is within the above range, the releasability and solubility in a solvent of the coating agent for a release film are enhanced.

[0048] The coating agent for a release film of the embodiment preferably contains a photoinitiator. The photoinitiator preferably generates radicals by irradiation with active energy rays. Examples of the photoinitiator include acetophenone-based initiators, benzoin ether-based initiators, benzophenone-based initiators, hydroxyalkylphenone-based initiators, thioxanthone-based initiators, amine-based initiators, acylphosphine oxide-based initiators, and the like. From the viewpoint of promoting the polymerization reaction and improving the curability, hydroxyalkylphenone-based initiators are preferable as the photoinitiator. The photoinitiator may be used alone or in combination of two or more. Examples of commercially available photoinitiators include "Irgacure 184" (manufactured by BASF Corporation), "Irgacure 907" (manufactured by BASF Corporation), and the like.

[0049] When containing a photoinitiator, the content of the photoinitiator is preferably 1 part by mass or more and 20 parts by mass or less, more preferably 10 parts by mass or more and 20 parts by mass or less, with respect to 100 parts by mass of the component having a reactive double bond.

[0050] In addition to the above-mentioned polyfunctional (meth)acrylate, monofunctional (meth)acrylate, perfluoropolyether compound, low molecular weight polymer, and photoinitiator, the coating agent for a release film of the embodiment can contain various additives as needed within a range that does not interfere with the effects of the present invention.

[0051] Examples of the additives include antioxidants, stabilizers, antistatic agents, defoaming agents, etc. The compounding amount of each additive may be appropriately selected according to the prior art.

[0052] The coating agent for the release film of the embodiment can easily and favorably form an uneven shape and has excellent releasability, so it can be suitably used as a coating agent for the release film.

[0053] (Release film) The release film of the embodiment includes a release layer formed using the above coating agent for the release film and a base material having the release layer on at least one surface.

[0054] The base material is not particularly limited and may be a base material generally used for release films. Examples of the base material include resin films such as polyethylene terephthalate, polyethylene, polyamide, and polypropylene, plastic films such as polyester-based resins and polyolefin-based resins, glassine paper, high-quality paper, etc., and resin films are preferred. The thickness of the base material is not particularly limited, but is preferably 10 μm or more and 300 μm or less, more preferably 20 μm or more and 130 μm or less.

[0055] The release layer is formed by applying the above coating agent for the release film on at least one surface of the base material, removing the solvent in the coating agent for the release film, and curing by irradiation with active energy rays. The release layer has an uneven shape on its surface.

[0056] Although the mechanism by which the uneven shape is manifested by the coating agent for the release film of the embodiment is not clear, it is presumed as follows. When the coating agent for the release film is applied onto the base material, due to the immiscibility between the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate in the coating agent for the release film, the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate separate. It is considered that the monofunctional (meth)acrylate, which has lower polarity and lower surface free energy than the polyfunctional (meth)acrylate, segregates on the surface of the release layer. Also, the perfluoropolyether compound moves between the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate.

[0057] When the coating agent for the release film is dried in the above state, the solvent in the coating agent for the release film volatilizes from the surface of the release layer. At this time, as the solvent volatilizes from the interface of the perfluoropolyether compound with high liquid repellency, gaps are formed in the monofunctional (meth)acrylate layer present on the surface. Thus, it is considered that an uneven shape (island structure) is formed on the surface of the release layer. Then, by irradiating the release film with active energy rays for curing, a release film provided with a base material and a release layer having an uneven shape on the surface is obtained.

[0058] FIG. 1 is an explanatory diagram for explaining the configuration of the release layer. FIG. 1 is a diagram showing the release layer and the base material formed according to the above mechanism. The release layer 1 is provided on the surface of the base material 2. In FIG. 1, an example in which the release layer 1 is provided on one side of the base material 2 is shown. The release layer 1 includes a first layer 11 containing polyfunctional (meth)acrylate as a main component, a second layer 12 containing a perfluoropolyether compound as a main component, and a third layer 13 containing monofunctional (meth)acrylate as a main component. "Main component" means the component with the highest content in each layer. The first layer 11 is formed on the base material 2. The second layer 12 is formed on the first layer 11. The third layer 13 is formed in an island shape on the second layer 12. The first layer 11 and the second layer 12 form recesses, and the third layer 13 forms protrusions (island portions).

[0059] The release film of the embodiment has a surface roughness Sa of 0.3 μm or more as defined by ISO 25178. Thus, the release film has a good concavo-convex shape by using the above-described coating agent for the release film.

[0060] For the release film of the embodiment, a silicone-based adhesive tape is attached to the cured film surface (release layer), cut into a width of 25 mm, and the peel force measured at a peel angle of 180° and a tensile speed of 0.3 m / min is less than 3.0 N / 25 mm. Thus, the release film can exhibit excellent releasability with respect to the object attached to the release layer.

[0061] As described above, since the release film of the embodiment has a good concavo-convex shape and excellent releasability, it can be suitably used, for example, as a protective film for a resin layer, a process film for manufacturing synthetic leather, etc., a process film for cast film formation of urethane resin, acrylic resin, vinyl chloride resin, etc. Furthermore, since the release film does not contain a silicone-based material, it can be suitably used at various stages in the manufacturing process of electronic devices such as ceramic green sheets and printed circuit boards. By laminating, for example, a resin layer on the release film having a concavo-convex shape, the concavo-convex shape can be transferred to the surface of the resin layer. The transfer shown in the present invention means that the concavo-convex shape of the release layer is reflected in the resin layer, and a concavo-convex shape in which the concavo-convex of the release layer is inverted is formed on the resin layer. Therefore, it can be suitably used particularly for a protective film for a resin layer or a process film for manufacturing synthetic leather, etc., where such transfer of the concavo-convex shape is required.

[0062] (Laminate) The laminate of the embodiment includes the above release film and a resin layer laminated on the release film. Since the laminate includes the above release film, the concavo-convex shape can be easily and favorably transferred to the surface of the resin layer in contact with the release film of the resin layer laminated on the release film.

[0063] The laminate of the embodiment may be formed by laminating, for example, the above release film and an adhesive film having a resin layer. The adhesive film may be any one having a resin layer, and known ones can be used. The adhesive film includes, for example, a resin layer (adhesive layer) and a base material. The resin layer and the base material are sequentially laminated on the release layer of the release film. The resin layer includes, for example, an acrylic resin, a thermoplastic resin, a thermosetting resin, a photocurable resin, etc., or a mixture or copolymer of two or more of them. Examples of the base material include the same ones as the base material of the above release film. The thickness of the base material is not particularly limited, but can usually be 10 μm or more and 300 μm or less.

[0064] The resin layer has an uneven shape on the surface on the side laminated on the release film. The uneven shape of the resin layer is formed by transferring the uneven shape formed on the surface of the release layer to the surface of the resin layer by laminating the resin layer on the release layer of the release film. In this way, by laminating the resin layer on the release film, an uneven shape can be easily formed on the surface of the resin layer.

[0065] The laminate of the embodiment can be easily peeled from the release film, and the uneven shape is well transferred to the surface of the resin layer from which the release film is peeled, so it can be widely used in various applications. Due to the uneven shape, the air permeability, design property, antiglare property, and visibility in a film or the like having a resin layer are improved. In particular, the adhesive film of the laminate can be preferably used for adherends such as displays of smartphones, personal computers, televisions, etc., and windows and exteriors of automobiles.

[0066] (Article having a release film) The article of the embodiment has the above release film. The method of applying (laminating) the release film to the surface of the article is not particularly limited, and an appropriate method may be used according to the article. Examples of the article include electronic devices, medical devices, synthetic leather, etc.

[0067] (Method for manufacturing a coating agent for a release film) The coating agent for a release film according to the embodiment is obtained by containing a polyfunctional (meth)acrylate, a monofunctional (meth)acrylate, a perfluoropolyether compound, a solvent, and, if necessary, other optional components such that the mass ratio of the polyfunctional (meth)acrylate to the monofunctional (meth)acrylate (polyfunctional (meth)acrylate: monofunctional (meth)acrylate) is 1:1.0 to 1:3.0. The coating agent for a release film is obtained by mixing the above components formulated so as to be within the above mass ratio range. As the mixing method, although not particularly limited, for example, a known method such as stirring can be used. Also, the order of addition of each component is not particularly limited.

[0068] By the manufacturing method of the coating agent for a release film according to the embodiment, a coating agent for a release film capable of easily and favorably developing an uneven shape can be obtained.

[0069] (Method for manufacturing a release film) The manufacturing method for a release film according to the embodiment includes a coating step of applying the coating agent for a release film to at least one surface of a base material, and a step of removing the solvent in the coating agent for a release film and forming a release layer having an uneven shape on the surface by irradiating active energy rays. Specifically, the release film is obtained by applying the coating agent for a release film to one or both surfaces of the base material surface, then drying together with the base material film to remove the solvent, and curing the release layer containing the coating agent for a release film by irradiating active energy rays.

[0070] As the coating method of the coating agent for a release film, although not particularly limited, for example, known methods such as gravure roll coating, comma coating, wire bar coating, lip coating, air knife coating, dip coating, etc. can be used.

[0071] The drying of the coating agent for the release film is preferably carried out by heating drying. By heating the coating agent for the release film, the evaporation of the solvent is promoted. Further, the molecular movement of each component of the perfluoropolyether compound, monofunctional (meth)acrylate, and polyfunctional (meth)acrylate is promoted, so that the concavo-convex shape is formed well. Furthermore, since perfluoropolyether exists on the surface of the concave portion in the release layer, excellent releasability is exhibited. The drying temperature and drying time may be appropriately set according to the blending components and component concentrations of the coating agent for the release film, etc.

[0072] As the active energy ray, usually, ultraviolet rays, electron beams, etc. are used, and ultraviolet rays are particularly preferable. By irradiating the above-mentioned active energy ray, the perfluoropolyether compound and alkyl (meth)acrylate, etc. in the coating agent for the release film are polymerized and cured. When an electron beam is used as the active energy ray, it is not necessary to add a photoinitiator to the coating agent for the release film.

[0073] The thickness of the release layer is not particularly limited, but is preferably 0.05 μm or more and 20 μm or less, more preferably 0.1 μm or more and 10 μm or less, and still more preferably 0.3 μm or more and 5 μm or less. In order to increase the thickness of the release layer, the application of the coating agent for the release film described above may be repeated several times.

[0074] The method for manufacturing the release film of the embodiment can easily form a concavo-convex shape on the release film by performing the normal manufacturing process of the release film by using the above-mentioned coating agent for the release film.

[0075] (Method for manufacturing a laminate) The method for manufacturing the laminate of the embodiment includes a coating step of applying the above-mentioned coating agent for the release film to at least one surface of the base material, a step of removing the solvent in the coating agent for the release film and irradiating with an active energy ray to form a release layer having a concavo-convex shape on the surface, and a step of laminating a resin layer on the surface of the release layer and transferring the concavo-convex shape to one surface of the resin layer.

[0076] Among the above steps, the coating step of applying the coating agent for the release film and the step of forming the release layer are the same as those in the method for manufacturing the release film.

[0077] As a method for laminating the resin layer, known techniques may be used. For example, by using a technique similar to the method of applying the coating agent for the release film, an adhesive such as an acrylic resin is applied to the surface of the release layer and dried, whereby the resin layer can be laminated (formed). By laminating the resin layer on the surface of the release layer, the uneven shape of the release layer can be transferred to one surface of the resin layer.

[0078] A substrate may be further provided on the resin layer. By bonding the substrate on the resin layer, a laminate of the adhesive film including the resin layer and the base material and the release film can be obtained.

[0079] The laminate may be manufactured by laminating a commercially available adhesive film including a resin layer and a base material, for example, on the surface of the release film, and bonding them while pressing with a rubber roller or the like, and transferring the uneven shape of the release layer to one surface of the resin layer.

[0080] In the method for manufacturing the laminate of the embodiment, by using the coating agent for the release film, the uneven shape of the release layer can be easily transferred to the resin layer by performing the manufacturing process of a normal laminate.

Examples

[0081] Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not intended to be limited to those examples.

[0082] <Preparation of Coating Agent for Release Film> [Example 1] Weigh each of the components shown in Table 1 below so as to have the composition (shown in mass %) shown in the same table, and mix them in a stirrer until they become uniform to obtain a coating agent for a release film of Example 1. The mass ratio of the polyfunctional (meth)acrylate to the monofunctional (meth)acrylate, the solid content concentration, and the contents of the monofunctional (meth)acrylate and the high molecular weight perfluoropolyether compound in terms of solid content are also shown in Table 1. Using the obtained coating agent for a release film, a release film was produced and evaluated by the method described below.

[0083] [Examples 2 to 5, Comparative Examples 1 to 6] Coating agents for release films of Examples 2 to 5 and Comparative Examples 1 to 6 were prepared in the same manner as in Example 1, except that the blending ratios of the respective components were as shown in Tables 1 to 2.

[0084]

Table 1

[0085]

Table 2

[0086] Details of each component shown in Tables 1 to 2 are as follows. Component (A): Polyfunctional acrylate ("Aronix M-306" manufactured by Toagosei Co., Ltd.) Component (B): Monofunctional (meth)acrylate (B-1) Lauryl methacrylate ("Light Ester L" manufactured by Kyoeisha Chemical Co., Ltd., the alkyl group is a straight chain with 12 carbon atoms) (B-2) Stearyl acrylate ("STA" manufactured by Osaka Organic Chemical Industry Co., Ltd., the alkyl group is a straight chain with 18 carbon atoms) (B-3) Isostearyl acrylate ("Light Ester S" manufactured by Kyoeisha Chemical Co., Ltd., the alkyl group is a branched chain with 18 carbon atoms) (B-4) Behenyl acrylate ("Blemmer VA" manufactured by NOF Corporation, the alkyl group is a straight chain with 22 carbon atoms) (B-5) Butyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., "Light Ester NB", the alkyl group is a straight chain with 4 carbon atoms) (B-6) Octyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., "NOAA", the alkyl group is a straight chain with 8 carbon atoms) Component (C): High molecular weight perfluoropolyether compound (having urethane acrylate at both ends, number average molecular weight (Mn) 6000) Component (D): Solvent Methyl ethyl ketone Component (E): Low molecular weight polymer (manufactured by Solvay Specialty Polymers Japan Co., Ltd., "FLUOROLINK AD-1700", a perfluoropolyether compound having difunctional urethane acrylate at both ends, number average molecular weight (Mn) 1700, a mixed solution of ethyl acetate - butyl acetate with a solid content of 70%) Component (F): Photoinitiator (F-1) "Irgacure 184" manufactured by BASF (F-2) "Irgacure 907" manufactured by BASF Note that component (C) is obtained by adding an isocyanate compound ("Karenz BEI" manufactured by Showa Denko K.K.) to a perfluoropolyether compound having hydroxyl groups at both ends ("FLUOROLINK D-6000" manufactured by Solvay Specialty Polymers Japan Co., Ltd.).

[0087] <Measurement of number average molecular weight (Mn)> The number average molecular weight (Mn) of the perfluoropolyether compound was measured using nuclear magnetic resonance (NMR) method. Under the following measurement conditions, 1 1H-NMR was measured, and the number average molecular weight (Mn) was obtained by comparing the integral values of the terminal group and the main chain. Specifically, in the case of (C): high molecular weight perfluoropolyether compound, using CFCl3 as the internal reference substance (0 ppm), the ratio of the integral values of the peak (-80.5 ppm) attributed to the terminal group and the peaks (-51.4 ppm and -87.5 ppm) attributed to the main chain was calculated, and the number average molecular weight (Mn) was calculated by calculating the degree of polymerization of the perfluoropolyether compound from the obtained ratio. Apparatus: "JNM-ECZ400S" (manufactured by JEOL Ltd.) Resonance frequency: 376 MHz Solvent: Hexafluorobenzene Number of integrations: 64 times

[0088] <Production of release film> Each coating agent (coating solution) for the release film obtained was uniformly coated on one side of a polyethylene terephthalate film (「Lumirror S10」manufactured by Toray Industries, Inc., thickness 38 μm) as a release substrate with a wire bar so that the film thickness after drying (after curing) would be 1 μm, and then heat-dried. Next, under room temperature and in a nitrogen atmosphere, ultraviolet rays were irradiated (light quantity: 1000 mJ / cm 2 ) with a UV irradiator to cure the release layer. Thereby, a release film having a release layer formed on the release substrate was produced. The coating agent for the release film of Comparative Example 2 did not form a coating film when coated on the substrate. For this reason, the release film of Comparative Example 2 could not be produced.

[0089] <Performance evaluation> [Surface shape evaluation] Each release film produced with the coating agents for the release film of Examples 1 to 5 and Comparative Examples 1, 5 to 6 was fixed to a stainless steel plate (SUS304) using a double-sided tape (「570E」manufactured by Sekisui Chemical Co., Ltd.) with the substrate on the lower side. The surface of the release film was observed for the surface shape at a temperature of 25°C and a relative humidity of 50% using a laser microscope (「OLE-5100」manufactured by Olympus Corporation, objective lens 「LMPLFLN50xLEXT」), and the arithmetic mean surface roughness Sa μm was measured. The magnification of the objective lens was 50 times and the measurement area was 1200 μm × 1200 μm. When the arithmetic mean surface roughness Sa was 0.3 μm or more, it was determined that the uneven shape was formed well. The measurement results are also shown in Tables 1 to 2. Surface shape images in the measurement area by a laser microscope are shown in FIGS. 2 to 9. FIG. 2 is a surface shape image of the release film of Example 1, FIG. 3 is a surface shape image of the release film of Example 2, FIG. 4 is a surface shape image of the release film of Example 3, FIG. 5 is a surface shape image of the release film of Example 4, FIG. 6 is a surface shape image of the release film of Example 5, FIG. 7 is a surface shape image of the release film of Comparative Example 1, FIG. 8 is a surface shape image of the release film of Comparative Example 5, and FIG. 9 is a surface shape image of the release film of Comparative Example 6.

[0090] Each release film prepared with the coating agent for the release film of Example 1 and Comparative Examples 3 to 4 was fixed to a stainless steel plate (SUS304) using a double-sided tape ("570E" manufactured by Sekisui Chemical Co., Ltd.) with the base material on the lower side. The surface of the release film was observed for the surface shape at a temperature of 25°C and a magnification of 200 times using an optical microscope ("VHX-5000", manufactured by Keyence Corporation). The obtained surface shape images are shown in FIGS. 10 to 12. FIG. 10 is a surface shape image of the release film of Example 1, FIG. 11 is a surface shape image of the release film of Comparative Example 3, and FIG. 12 is a surface shape image of the release film of Comparative Example 4.

[0091] [Release property evaluation] A silicone-based adhesive tape ("No. 642 tape" manufactured by Daisoku Seisakusho Co., Ltd.) was laminated on each release film prepared with the coating agent for the release film of Examples 1 to 5 and Comparative Examples 1, 3, 5, and 6 while pressing with a 2 kg rubber roller, and left standing at room temperature for 30 minutes to obtain a laminated film. A test piece obtained by cutting the obtained laminated film into a width of 25 mm was peeled at a peeling angle of 180° and a tensile speed of 0.3 m / min at room temperature, and the force required for peeling was measured using a tensile testing machine ("Autograph AG-1kNXplus with thermostat" manufactured by Shimadzu Corporation). This force was defined as the peeling force. When the peeling force was less than 3.0 N / 25 mm, the release property was determined to be good. The results are also shown in Tables 1 to 2.

[0092] [Example 6] [Shape transferability evaluation] Using a release film, the laminate of Example 6 was produced by the following method, and the shape transferability of the uneven shape was evaluated by observing the shapes of the release layer and the resin layer, respectively. Using the coating agent for the release film of Example 1, a release film was produced by the above method for producing a release film. On the surface of the release layer of the release film, an acrylic adhesive (「BPS-5160」manufactured by Toyochem Co., Ltd., non-volatile component concentration 33% by mass, solvent: ethyl acetate / toluene / isopropyl alcohol) was uniformly applied with a wire bar so that the film thickness after drying was 25 g / m 2 Then, it was dried at 100 °C for 2 minutes to form a resin layer. A polyethylene terephthalate film (「Lumirror S10」manufactured by Toray Industries, Inc., thickness 38 μm) as an adhesive base material was laminated on the resin layer to produce an adhesive film. Thereby, a laminate of a release film and an adhesive film was obtained. The obtained laminate was peeled at the interface between the release layer and the resin layer, and each surface was observed with a laser microscope in the same manner as above to evaluate whether the corresponding uneven shape was formed. The surface shape images in the measurement region are shown in FIGS. 13 to 14. FIG. 13 is a surface shape image of the release layer in the laminate of Example 6, and FIG. 14 is a surface shape image of the resin layer in the laminate of Example 6.

[0093] As is clear from Tables 1 to 2 and FIGS. 2 to 14, in the coating agents for the release films of Examples 1 to 5, an uneven shape could be easily and favorably formed on the surface, and the releasability was also good. As shown in the surface shape images, in the release films of Examples 1 to 5, a plurality of convex portions (island portions) were formed on the surface. On the other hand, in Comparative Examples 1, 3 to 6, the formation of the uneven shape was poor. In the release films of Comparative Examples 1, 3 to 6, almost no convex portions were formed on the surface, or the height of the convex portions was insufficient. Further, in Comparative Example 2, a stable release layer could not be formed.

[0094] From Examples 1 to 5 and Comparative Examples 1 to 2, it was confirmed that when the mass ratio of the polyfunctional (meth)acrylate to the monofunctional (meth)acrylate was 1:1.0 to 1:3.0, a release layer with a good uneven shape could be obtained. From Examples 1 to 5 and Comparative Examples 4 to 5, it was confirmed that the coating agent for a release film can form a concavo-convex shape well by containing a monofunctional (meth)acrylate having a long-chain alkyl group with 12 or more carbon atoms. It is presumed that in the case of a monofunctional (meth)acrylate having an alkyl group with less than 12 carbon atoms, the concavo-convex shape is not well developed because it is compatible with the polyfunctional acrylate. From Example 1 and Comparative Examples 3 and 6, it was confirmed that the coating agent for a release film can form a concavo-convex shape well and has excellent releasability by containing a high molecular weight perfluoropolyether compound.

[0095] As is clear from FIGS. 13 to 14, in the laminate using the coating agent for a release film of the example, the concavo-convex shape in the release layer and the concavo-convex shape in the resin layer are almost the same. That is, a concavo-convex shape obtained by almost inverting the concavo-convex shape in the release layer is formed in the resin layer. Therefore, it was confirmed that the concavo-convex shape of the release layer is well transferred to the surface of the resin layer.

[0096] The embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is shown by the scope of the claims, and includes all modifications within the meaning and scope equivalent to the scope of the claims.

Claims

1. A release film coating agent containing a polyfunctional (meth)acrylate, a monofunctional (meth)acrylate having an alkyl group with 12 or more carbon atoms, a perfluoropolyether compound having a number average molecular weight of 4000 or more and having a (meth)acryloyl group, and a solvent, wherein the content ratio of the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate is 1:1.0 to 1:3.0 in terms of mass ratio (polyfunctional (meth)acrylate: monofunctional (meth)acrylate). A release film coating agent.

2. The content of the monofunctional (meth)acrylate is 40% by mass or more and 60% by mass or less in the solid content of the release film coating agent. The release film coating agent according to Claim 1.

3. The content of the perfluoropolyether compound is 0.5% by mass or more and 20% by mass or less in the solid content of the release film coating agent. The release film coating agent according to Claim 1 or Claim 2.

4. A release film comprising a base material and a release layer formed on at least one surface of the base material, wherein the release layer contains a polyfunctional (meth)acrylate, a monofunctional (meth)acrylate having an alkyl group with 12 or more carbon atoms, and a perfluoropolyether compound having a number average molecular weight of 4000 or more and having a (meth)acryloyl group, and the content ratio of the polyfunctional (meth)acrylate and the monofunctional (meth)acrylate is 1:1.0 to 1:3.0 in terms of mass ratio (polyfunctional (meth)acrylate: monofunctional (meth)acrylate). A release film.

5. The release layer has an uneven shape on its surface. The release film according to Claim 4.

6. A release film comprising a base material and a release layer formed on at least one surface of the base material, wherein the release layer comprises a first layer formed on the base material and containing a polyfunctional (meth)acrylate, a second layer formed on the first layer and containing a perfluoropolyether compound, and a third layer formed in an island shape on the second layer and containing a monofunctional (meth)acrylate. A release film.

7. A laminate comprising the release film according to any one of Claims 4 to 6 and a resin layer laminated on the release film. A laminate.

8. The surface of the resin layer in contact with the release film has an uneven shape. The laminate according to Claim 7.

9. A laminate comprising the release film according to Claim 5 and a resin layer laminated on the release film. The concavo-convex shape on the surface of the resin layer is formed by transferring the concavo-convex shape on the surface of the release layer in the release film. Laminated body.

10. An article having the release film according to any one of Claims 4 to 6. Article.

Images