WO2022202383A1

WO2022202383A1 - Release sheet

Info

Publication number: WO2022202383A1
Application number: PCT/JP2022/010757
Authority: WO
Inventors: 会美子古野; 泰紀柄澤
Original assignee: リンテック株式会社
Priority date: 2021-03-26
Filing date: 2022-03-11
Publication date: 2022-09-29
Also published as: JPWO2022202383A1; TW202302662A

Abstract

The present invention pertains to a release sheet having a base material and a release layer formed on the base material. The release layer is formed from a release agent composition containing a silicone-modified acrylic resin (A), a melamine resin (B), an acid catalyst (C), and a filler (D); and the amount of silicon modification in the solid content of the silicone-modified acrylic resin (A) is 0.3 to 0.5 mmol/g.

Description

release sheet

The present invention relates to a release sheet.

In general, a release sheet (sometimes referred to as a "process sheet") has a substrate such as paper, plastic film, or polyethylene laminated paper, and a release layer provided on the substrate. The release layer is formed by applying a release agent composition containing a reactive compound onto a substrate and curing the composition.
The release sheet is widely used as, for example, a protective sheet for the adhesive layer of an adhesive sheet or the like, a process film for producing a resin sheet, a process film for forming a ceramic green sheet, a process film for producing synthetic leather, etc. (e.g. , see Patent Documents 1 to 6).

In addition, a transfer sheet (transfer foil) having a protective layer (hard coat layer) and an adhesive layer on the release layer of the release sheet (transfer foil) in this order, and a functional layer such as a decorative layer between the protective layer and the adhesive layer A transfer sheet having an imparting layer, a transfer sheet having a protective layer and a functional adhesive layer, and the like are known. By laminating the transfer sheet on the object and peeling off the release sheet, the surface of the object can be imparted with hard coat properties, decorative properties, or arbitrary functionality.
By the way, in such a transfer sheet, the transfer resin of the protective layer and the adhesive layer is a curable resin composition, and the release sheet may be removed after the transfer sheet is laminated on the object and heat-bonded. . At that time, while the transfer sheet is laminated on the object, processing such as cutting may be performed in a state before the protective layer and the adhesive layer are cured. Therefore, in the state before the protective layer and the adhesive layer are cured, it is necessary to have peeling properties such that the protective layer does not peel off from the peeling layer to the extent that unintended peeling does not occur during processing such as cutting. On the other hand, in the state after the protective layer and the adhesive layer are cured, release properties are required so that the protective layer can be easily separated from the release layer.

WO2009/122984 JP 2017-171617 A JP 2018-104661 A JP 2019-171617 A JP 2020-146890 A JP 2020-153022 A

However, when the protective layer and the adhesive layer change from an uncured state to a cured state, a chemical state change occurs in which the intermolecular force and polarity between the release layer and the protective layer change, and the protective layer and/or the adhesive layer change. Curing of the adhesive layer causes a change in physical state that results in an order of magnitude difference in modulus between the release layer and these layers. Due to such chemical and physical state changes, it is extremely difficult to control the releasability of the interface between the release layer and the protective layer. Furthermore, since the protective layer and the adhesive layer are sometimes cured by a heat press treatment, it is necessary to consider the influence of the temperature and pressure of the heat press treatment in order to control the releasability. Therefore, the release layer will not be peeled off from the protective layer by processing such as cutting in the uncured state of the protective layer before the heat press treatment, and the release layer will not be removed in the cured state of the protective layer after the heat press treatment. Development of a release sheet that can be easily peeled from the protective layer has been strongly desired.

Therefore, according to the present invention, the release layer does not separate from the protective layer due to processing such as cutting before the hot press treatment, and the release layer can be easily separated from the protective layer after the hot press treatment. An object of the present invention is to provide a release sheet.

The present inventors have found that a release sheet having a release layer formed from a release agent composition containing a silicone-modified acrylic resin whose amount of silicone modification is controlled, a melamine resin, an acid catalyst, and a filler is one of the above-described problems. can be solved.

That is, the present invention relates to the following [1] to [6].
[1] having a base material and a release layer formed on the base material,
The release layer is a layer formed from a release agent composition containing a silicone-modified acrylic resin (A), a melamine resin (B), an acid catalyst (C), and a filler (D),
The release sheet, wherein the amount of silicone modification in the solid content of the silicone-modified acrylic resin (A) is 0.3 to 0.5 mmol/g.
[2] The above [1], wherein the mass ratio (A)/(B) of the silicone-modified acrylic resin (A) and the melamine resin (B) is 50/50 to 95/5 in terms of solid content. The release sheet described in .
[3] In the above [1] or [2], wherein the content of the acid catalyst (C) is 0.1 to 20 parts by mass based on 100 parts by mass of the melamine resin (B) in terms of solid content. Release sheet as described.
[4] When the resin component is obtained by removing the filler (D) from the total solids of the release agent composition, the content of the filler (D) is 15 to 75 parts by mass with respect to 100 parts by mass of the resin component. The release sheet according to any one of [1] to [3] above, which is parts by mass.
[5] The proportion of the silicone-modified acrylic resin (A) in the total solid content of the silicone-modified acrylic resin (A), the melamine resin (B), the acid catalyst (C), and the filler (D) The release sheet according to any one of [1] to [4] above, which has a silicone modification amount of 0.18 to 0.40 mmol/g.
[6] The release sheet according to any one of [1] to [5] above, wherein the filler (D) contains boron nitride particles.

According to the present invention, the release layer does not separate from the protective layer due to processing such as cutting before the hot press treatment, and the release layer can be easily separated from the protective layer after the hot press treatment. It becomes possible to provide a release sheet.

1 is a schematic cross-sectional view of a release sheet according to an embodiment of the invention; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
The release sheet (sometimes referred to as a "process film") of the present invention has a base material and a release layer formed on the base material, and the release layer is made of a silicone-modified acrylic resin (A) (hereinafter referred to as " (A) component”), a melamine resin (B) (hereinafter also referred to as “(B) component”), an acid catalyst (C) (hereinafter also referred to as “(C) component”), and a filler ( D) (hereinafter also referred to as "(D) component"), and the amount of silicone modification in the solid content of the silicone-modified acrylic resin (A) is 0.3 to 0. .5 mmol/g.
In the present invention, in the release agent composition containing components (A) to (D), by controlling the amount of silicone modification of the silicone-modified acrylic resin (A), the release layer can be formed by processing such as cutting before heat press treatment. does not peel off from the protective layer, and the peel layer can be easily peeled off from the protective layer after the hot press treatment.

As used herein, the term "active ingredient" refers to the components contained in the release agent composition, excluding the diluent solvent.
Further, in this specification, the "resin component" is the total solid content of the release layer (release agent composition) excluding the fillers (organic filler and inorganic filler). That is, even if the filler (D) contains an organic filler, the resin component does not contain an organic filler.
Furthermore, for preferred numerical ranges (for example, ranges of content etc.), the stepwise lower and upper limits can be independently combined. For example, from the statement "preferably 10 to 90, more preferably 30 to 60", combining "preferred lower limit (10)" and "more preferred upper limit (60)" to "10 to 60" can also

[Structure of release sheet]
The release sheet of the present invention has a substrate and a release layer provided on the substrate.
FIG. 1 is an example of a schematic cross-sectional view showing a release sheet according to an embodiment of the present invention. The release sheet 1A has a base material 10 and a release layer 11 provided on the base material 10 . The release layer 11 is a crosslinked release agent composition containing a silicone-modified acrylic resin (A), a melamine resin (B), an acid catalyst (C), and a filler (D) (12 in FIG. 1). It is a thing.
Note that, between the base material 10 and the release layer 11, other layers such as an easy adhesion layer and an antistatic layer (not shown) may be provided.
The release layer and base material constituting the release sheet of the present invention are described below.

<Release layer>
The release layer of the release sheet of the present invention can be formed from a release agent composition containing a silicone-modified acrylic resin (A), a melamine resin (B), an acid catalyst (C), and a filler (D). can.
The release agent composition, which is the material for forming the release layer, will be described below.
In the following description, "the content of each component with respect to the total amount of active ingredients in the release agent composition" may also be regarded as "the content of each component in the release layer formed from the release agent composition". can.

<<Removing agent composition>>
The present inventors have found that the release layer formed from the release agent composition does not separate from the protective layer by processing such as cutting before the heat press treatment, while the release layer formed from the release agent composition does not separate from the release agent composition after the heat press treatment. Various investigations were conducted on prescriptions for enabling the formed release layer to be easily separated from the protective layer. As a result, in the release agent composition in which the release layer contains the silicone-modified acrylic resin (A), the melamine resin (B), the acid catalyst (C), and the filler (D), the silicone-modified acrylic resin (A) It has been found that controlling the amount of silicone modification of is an effective formulation.
Based on these results, the present inventors have developed a release agent containing a silicone-modified acrylic resin (A) in which the amount of silicone modification is controlled, a melamine resin (B), an acid catalyst (C), and a filler (D). The inventors have found that a release sheet having a release layer formed from the composition can solve the above problems, and have completed the present invention.

In one aspect of the present invention, the release agent composition may or may not contain additives other than the above components (A) to (D) within a range that does not impair the effects of the present invention. It doesn't have to be.

Each component contained in the release agent composition will be described below.

(Silicone-modified acrylic resin (A))
The silicone-modified acrylic resin (A) used in the present invention can function as a base release agent. The silicone-modified acrylic resin (A) can be obtained by modifying an acrylic resin with a silicone modifier. Examples of the method of modifying an acrylic resin with a silicone modifier include a method of reacting an acrylic resin having a functional group with a silicone modifier having a functional group. The above acrylic resin having a functional group is an acrylic resin having a functional group capable of reacting with the terminal functional group of the silicone modifier. Moreover, the silicone modifier having a functional group is a silicone modifier having a terminal functional group capable of reacting with the functional group of the acrylic resin.

Examples of acrylic resin monomers include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, glycidyl (meth) acrylate, 2-hydroxyethyl ( meth)acrylate, 2-hydroxypropyl (meth)acrylate, and the like. These may be used individually by 1 type, and may use 2 or more types together. An acrylic resin can be obtained by polymerizing these monomers by a known method.
In this specification, "(meth)acrylic acid" is a concept including both "acrylic acid" and "methacrylic acid".

Examples of silicone modifiers include organopolysiloxanes having organic groups such as dimethylpolysiloxane. Examples of organic groups include phenyl, methyl, ethyl, isopropyl, hexyl, cyclohexyl, and vinyl groups. These may be used individually by 1 type, and may use 2 or more types together.

Examples of functional groups in acrylic resins and silicone modifiers include hydroxyl group, amino group, carboxyl group, thiol group, isocyanate group, epoxy group, hydrosilyl group, ethynyl group, ammonium group, amide group, imino group, alkoxysilyl group, ether groups, sulfonic acid groups, nitrile groups, and the like.
Further, as a reaction between the functional group of the acrylic resin and the functional group of the silicone modifier, specifically, an active hydrogen group present in a hydroxyl group, a primary amino group, a secondary amino group, a carboxyl group, a thiol group, or the like, reaction with an isocyanate group or an epoxy group; esterification reaction between a hydroxyl group and a carboxyl group; hydrosilylation reaction between a hydrosilyl group and an ethynyl group;

The silicone-modified resin (A) can also be obtained by polymerizing a mixture of an acrylic resin monomer and a silicone modifier having an acrylate functional group.

Some of these silicone-modified acrylic resins (A) on the market are previously blended with a melamine resin or the like as a curing agent for curing component (A). When such a commercially available product is used, the melamine resin or the like blended as a curing agent in the above commercial product is treated as the melamine resin (B) component described later, and the remaining silicone-modified acrylic resin is treated as (A). treated as an ingredient.
Examples of commercially available products containing silicone-modified acrylic resin (A) and melamine resin (B) include x-62-9088 and x-62-9089 (both of which are trade names manufactured by Shin-Etsu Chemical Co., Ltd.). , and TA31-291F (manufactured by Showa Denko Materials Co., Ltd., trade names).

The silicone-modified acrylic resin (A) used in the present invention has a specific amount of silicone modification. As used herein, the term "silicone-modified amount" refers to the amount (mmol) of silyl groups represented by the following formula (X) per 1 g of the solid content of the silicone-modified acrylic resin (A).
R and R' in formula (X) are organic groups in the silicone modifier. R and R' may be the same or different.

The amount of silicone modification in the solid content of the silicone-modified acrylic resin (A) is 0.3 to 0.5 mmol/g. If it is less than the above lower limit, it may be difficult to separate the release layer from the protective layer after heat press treatment. On the other hand, when the above upper limit is exceeded, there is a possibility that the release layer may be easily separated from the protective layer before the heat press treatment. From the viewpoint of making it possible to easily peel off the release layer from the protective layer after the heat press treatment and to prevent the release layer from easily peeling off from the protective layer before the heat press treatment, silicone The amount of silicone modification in the solid content of the modified acrylic resin (A) is preferably 0.32 to 0.48 mmol/g, more preferably 0.34 to 0.45 mmol/g, and more preferably 0.35 to 0.35 mmol/g. It may be 43 mmol/g.
The amount of silicone modification in the solid content of the silicone-modified acrylic resin (A) may be adjusted using two or more silicone-modified acrylic resins (A).

In one aspect of the present invention, the silicone of the silicone-modified acrylic resin (A) in the total solid content of the silicone-modified acrylic resin (A), the melamine resin (B), the acid catalyst (C), and the filler (D) The amount of modification is preferably 0.18 to 0.40 mmol/g, more preferably 0.20 to 0.36 mmol/g, still more preferably 0.21 to 0.33 mmol/g, and even more It is preferably 0.22 to 0.30 mmol/g. When the amount of silicone modification in components (A) to (D) is within the above numerical range, the release layer can be easily peeled off from the protective layer after heat press treatment, and protection before heat press treatment. It can be even better to prevent the release layer from peeling easily from the layer.

In one aspect of the present invention, the mass ratio (A)/(B) of the silicone-modified acrylic resin (A) and the melamine resin (B) is preferably 50/50 to 95/5 in terms of solid content, More preferably 55/45 to 90/10, still more preferably 60/40 to 85/15. When the mass ratio (A)/(B) is equal to or higher than the lower limit, the peeling layer is prevented from being easily peeled off from the protective layer, and the flexibility of the peeling layer decreases, causing delamination. prevent it from becoming easier. On the other hand, when the mass ratio (A)/(B) is equal to or less than the upper limit, insufficient curing of the release agent composition in the release layer is suppressed, and the release of the release layer from the protective layer becomes unstable. to prevent the release layer components from easily migrating to the protective layer.

The total content of the silicone-modified acrylic resin (A) and melamine resin (B) in the release agent composition is not particularly limited, but in terms of solid content, the silicone-modified acrylic resin (A) and the melamine resin (B) And, with respect to a total of 100 parts by mass of the acid catalyst (C) and the filler (D), it is preferably 40 to 85 parts by mass, more preferably 50 to 80 parts by mass, and still more preferably 55 to 75 parts by mass. . The total content of the silicone-modified acrylic resin (A) and the melamine resin (B) in the release agent composition is the silicone-modified acrylic resin (A), the melamine resin (B), the acid catalyst (C), and the filler ( If it is at least the above lower limit with respect to the total of 100 parts by mass of D), the peeling layer can be easily peeled off from the protective layer after the heat press treatment. Moreover, when it is equal to or less than the above upper limit, it is possible to prevent the release layer from easily peeling off from the protective layer before the heat press treatment.

(Melamine resin (B))
The melamine resin (B) can function as a cross-linking agent for the silicone-modified acrylic resin (A).
By including the melamine resin (B) in the release agent composition, the film strength of the release layer formed by the release agent composition can be improved.

Examples of the melamine resin (B) include methylolated melamine resins, iminomethylolated melamine resins, and alkylated melamine resins. These may be used individually by 1 type, and may use 2 or more types together.
For example, the alkylated melamine resin is obtained by alkyl-etherifying some or all of the methylol groups in the methylolated melamine resin with an alkyl monoalcohol. The type and etherification rate of the alkyl monoalcohol are not particularly limited, and compatibility with the silicone-modified acrylic resin (A), solubility in solvents, curability of the obtained release agent composition, adhesion to the substrate, etc. can be selected as appropriate.
Specific examples of alkylated melamine resins include methylated melamine resin; ethylated melamine resin; propylated melamine resin; butylated melamine resin such as normal butylated melamine resin and isobutylated melamine resin; octylated melamine resin such as octylated melamine resin; These may be used individually by 1 type, and may use 2 or more types together.

Commercially available methylolated melamine resins include Nicalac MS-11 and Nicalac MW-12LF (both of which are trade names manufactured by Sanwa Chemical Co., Ltd.).
Commercially available iminomethylolated melamine resins include Nicalac MS-001, MX-750, MX-706, and MX-035 (all trade names, manufactured by Sanwa Chemical Co., Ltd.).
Commercially available iminated melamine resins include Nicalac MZ-351 and Nicalac MX-730 (both of which are trade names manufactured by Sanwa Chemical Co., Ltd.).
Commercially available methylated melamine resins include Cymel 303, Cymel 325, Cymel 327, Cymel 350, and Cymel 370 (all of which are trade names manufactured by Nippon Cytec Industries Co., Ltd.), and Tesfine 200 (manufactured by Hitachi Kasei Polymer Co., Ltd.). , trade name) and the like.

Further, the silicone-modified acrylic resin (A) and the melamine resin (B) may be prepared separately, or may be prepared by mixing the silicone-modified acrylic resin (A) and the melamine resin (B) in advance. may be used.

(Acid catalyst (C))
By using the acid catalyst (C) in the release agent composition, it is possible to accelerate the curing of the melamine resin (B) and increase the film strength of the release layer.
Examples of the acidic catalyst (C) include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid and boric acid; carboxylic acids (organic acids) such as acetic acid, monochloroacetic acid, dichloroacetic acid and butyric acid; benzenesulfonic acid and p-toluenesulfone. organic sulfonic acids (organic acids) such as acids, xylenesulfonic acid, p-phenolsulfonic acid, methanesulfonic acid and ethanesulfonic acid; alkyl phosphates (organic acids); These may be used individually by 1 type, and may use 2 or more types together.
The content of the acidic catalyst is not particularly limited, but is preferably 0.1 to 20 parts by mass, more preferably 1 to 18 parts by mass, based on 100 parts by mass of the melamine resin (B) in terms of solid content. parts by mass, more preferably 5 to 15 parts by mass.

(Filler (D))
A filler (D) is contained in the release agent composition. The filler (D) functions to impart matte properties to the protective layer or the like in contact with the release layer by forming unevenness on the surface of the release layer.

The average particle size of the filler (D) is not particularly limited, and is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm from the viewpoint of imparting matte properties and preventing particle dropout.
The average particle size of the filler (D) is measured by observing the filler in the cross section of the release film with a scanning electron microscope, observing 100 fillers, and taking the average value as the average particle size. can be done.

The shape of the filler (D) is not particularly limited, and may be either spherical or non-spherical irregular shape.

The filler (D) may be either an organic filler or an inorganic filler, and an organic filler and an inorganic filler may be used in combination.
Specific examples of the organic filler include crosslinked polymethyl methacrylate particles, crosslinked methyl methacrylate-styrene copolymer particles, crosslinked polystyrene particles, crosslinked methyl methacrylate-methyl acrylate copolymer particles, and crosslinked alkyl acrylate-styrene copolymer particles. particles, crosslinked alkyl methacrylate-styrene copolymer particles, melamine/formaldehyde resin particles, benzoguanamine/formaldehyde resin particles, resin particles such as polyacrylonitrile resin particles, and the like. These may be used individually by 1 type, and may use 2 or more types together.
Specific examples of inorganic fillers include boron nitride particles and silica particles. These may be used individually by 1 type, and may use 2 or more types together.

The content of the filler (D) is not particularly limited, and is preferably 15 to 75 parts by mass, more preferably 25 to 70 parts by mass, based on 100 parts by mass of the resin component, from the viewpoint of imparting matte properties and preventing particles from falling off. Department.

(Total content of silicone-modified acrylic resin (A), melamine resin (B), acid catalyst (C), filler (D))
The total content of silicone-modified alkyd resin (A), melamine resin (B), acid catalyst (C), and filler (D) in the release layer (hereinafter referred to as "total amount of components (A) to (D)") There are no particular restrictions on the The total amount of components (A) to (D) in the release layer is preferably 60 parts by mass or more, more preferably 70 parts by mass or more, and even more preferably 80 parts by mass or more, more preferably 90 parts by mass or more, particularly preferably 95 parts by mass or more, and may be substantially 100 parts by mass.

(Other additives)
The release agent composition may contain additives other than the components (A) to (D) as long as they do not impair the object of the present invention.
Examples of such additives include various additives such as antioxidants, ultraviolet absorbers, antistatic agents, surfactants, photoinitiators, light stabilizers, matting agents, viscosity modifiers, and leveling agents. mentioned. These may be used individually by 1 type, and may use 2 or more types together.
When the release agent composition contains the other additive, the content of the other additive is preferably 30 parts by mass with respect to 100 parts by mass of the total amount of components (A) and (B). part or less, more preferably 0.1 to 15 parts by mass, still more preferably 0.1 to 5 parts by mass.

(Dilution solvent)
The release agent composition may be in the form of a solution by adding a diluent solvent to the various active ingredients described above, from the viewpoint of improving coatability onto the substrate.
The diluting solvent is selected from organic solvents in which the above components (A) to (D) are well soluble.
Examples of such organic solvents include toluene, xylene, hexane, heptane, octane, methanol, ethanol, isopropyl alcohol, isobutanol, n-butanol, ethyl acetate, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, and the like. These may be used individually by 1 type, and may use 2 or more types together.
As the organic solvent used as the diluent solvent, the organic solvent used in synthesizing the above-described component (A) or component (B) may be used as it is. In addition, as a diluent solvent, the organic solvent used in the synthesis of the above component (A) or component (B) and/or one or more other organic solvents is added so that the release agent composition can be applied uniformly. may be added.
When using a release composition solution obtained by adding a diluent solvent to the release composition, it is preferable to apply the above solution onto a substrate to form a coating film, and then heat and dry the coating film.

The amount of the diluent solvent may be appropriately selected so that the release agent composition has an appropriate viscosity when applied.
The solid content concentration of the release agent composition solution is not particularly limited, but is preferably 0.1 to 60% by mass, more preferably 0.2 to 50% by mass, and particularly preferably 0.5 to 40% by mass. be.

<Thickness of release layer>
Although the thickness of the release layer is not particularly limited, it is usually 25 to 5000 nm, preferably 100 to 4000 nm. If the thickness of the release layer is 25 nm or more, it is possible to suppress variations in the peel force due to variations in the coating amount. Moreover, if the thickness of the release layer is 5000 nm or less, the curability of the coated film of the release agent composition can be improved.
The thickness of the release layer is measured, for example, by the method described in Examples below.

<Surface of release layer>
Arithmetic mean roughness Ra (surface roughness)
The release layer has an uneven surface, and the arithmetic mean roughness Ra of the release layer, which is measured according to JIS B 0601-2013, is preferably 500 to 650 nm from the viewpoint of matte properties and peelability. and more preferably 500 to 600 nm.
The arithmetic mean roughness Ra can be adjusted by selecting the resin component, and the particle size and content of the filler (D).
More specifically, the arithmetic mean roughness Ra of the release layer is measured by the method described in Examples below.

<Base material>
The substrate used for the release sheet of the present invention is not particularly limited as long as it can support the release layer, and examples thereof include paper substrates and resin films.
Examples of paper substrates include papers such as woodfree paper, medium-quality paper, glassine paper, art paper, coated paper, clay-coated paper, cast-coated paper, and kraft paper; laminated paper obtained by laminating resin; synthetic paper; and the like. These may be used individually by 1 type, and may use 2 or more types together.
Examples of resin films include polyolefin resins such as polyethylene resins, polypropylene resins, and polymethylpentene resins; polyester resins such as polybutylene terephthalate resins, polyethylene terephthalate resins, and polyethylene naphthalate resins; polyetherimide resins; acetate resins; a film made of a synthetic resin such as vinyl chloride resin; These may be used individually by 1 type, and may use 2 or more types together.
The substrate may be a single layer or multiple layers of two or more layers of the same or different types.
The thickness of the substrate is not particularly limited, but is usually 5 to 300 μm, preferably 10 to 200 μm. When the thickness of the base material is 5 to 300 μm, for example, it is possible to impart stiffness and strength suitable for processing such as printing, cutting, and sticking to adhesive sheets using release sheets.

In the case of using a synthetic resin as the base material, the surface of the base material on which the release layer is to be provided may optionally be subjected to a method such as an oxidation method or a roughening method in order to improve the adhesion between the base material and the release layer. can be treated.
Examples of the oxidation method include corona discharge surface treatment, chromic acid surface treatment (wet), flame surface treatment, hot air surface treatment, ozone and ultraviolet irradiation surface treatment, and the like. In addition, examples of the roughening method include a sandblasting method, a solvent treatment method, and the like. These surface treatment methods are appropriately selected according to the type of substrate, but generally, the corona discharge surface treatment method is preferably used from the viewpoint of effectiveness and operability. A primer treatment can also be applied.

The release sheet of the present invention may be subjected to embossing or the like on the release layer side surface to form unevenness on the surface of the release sheet.
In addition, the release sheet of the present invention may consist only of a base material and a release layer, or may be provided with other layers such as an easy-adhesion layer and an antistatic layer between the base material and the release layer. good. By providing the release sheet with the easy-adhesion layer, it is possible to effectively prevent the release layer from falling off from the release sheet.

The easy-adhesion layer is usually formed by applying an easy-adhesion coating agent on the release layer-side surface of the substrate. Examples of easily adhesive coating agents include polyester resins, urethane resins, acrylic resins, melamine resins, oxazoline group-containing resins, carbodiimide group-containing resins, epoxy group-containing resins, isocyanate-containing resins, and copolymers thereof. Also, a coating agent containing natural rubber or synthetic rubber as a main component, and the like are included. These may be used individually by 1 type, and may use 2 or more types together.
In addition, in order to improve the applicability of the easy-adhesion coating agent to the substrate surface and the adhesion between the substrate and the easy-adhesion layer, the surface of the substrate to be coated with the easy-adhesion coating agent is subjected to chemical treatment and discharge treatment. You may perform surface treatments, such as.

The thickness of the easy-adhesion layer is not particularly limited, but is preferably 50 nm to 5 μm, more preferably 100 nm to 1 μm. When the thickness of the easy-adhesion layer is at least the above lower limit, the effect of the easy-adhesion layer can be favorably obtained. Therefore, the workability of applying the release agent composition onto the easy-adhesion layer is improved.

[Peeling force for peeling the release sheet from the object]
In general, the peel force for peeling the release sheet from the object varies depending on the application and the types of protective layers and adhesive layers to be laminated. In addition, there are cases where a low peel force is preferable so that the peeling operation at the time of peeling is smooth, and there are cases where a high peel force is preferable so as to improve the retention of the object until the peeling operation.
The peel force for peeling the release sheet from the object varies depending on the thickness and hardness of the base material of the release sheet, the rigidity of the object, the components and physical properties of the protective layer and adhesive layer, and the like. Therefore, in the present specification, the peel force is evaluated by the method described in Examples described later.

[Manufacturing method of release sheet]
The release sheet of the present invention can be produced, for example, by coating a release agent composition on at least one surface of a substrate, heat-treating the release agent composition, and curing the release agent composition to form a release layer. can be done.
The coating film formed on the substrate may be cured by heating. When the components (A) and (B) have functional groups that react with active energy rays, the coating film may be cured by irradiation with active energy rays. Moreover, the coating film may be cured using both heating and irradiation with active energy rays. Examples of active energy rays include ultraviolet rays and electron beams.
The stripper composition may be in the form of a solution diluted with a diluent solvent, as described above.

The heat treatment temperature is not particularly limited, but is preferably 80 to 250°C, more preferably 100 to 230°C, even more preferably 100 to 170°C, and particularly preferably 130 to 160°C.
The heat treatment time is not particularly limited, but is preferably 15 seconds to 5 minutes, more preferably 20 seconds to 5 minutes, and particularly preferably 30 seconds to 3 minutes.

Examples of coating methods for the release agent composition include gravure coating, bar coating, spray coating, spin coating, knife coating, air knife coating, roll coating, roll knife coating, blade coating, gate roll coating method, die coating method, and the like. These may be used individually by 1 type, and may use 2 or more types together.

The coating thickness of the release agent composition is adjusted so that the thickness of the resulting release layer falls within the above range.

[Use of release sheet]
The release sheet of the present invention can be used as a protective sheet for various adhesive bodies such as adhesive sheets. It is used by attaching it to the surface. It can also be used as a process film when producing various resin sheets, ceramic green sheets, synthetic leathers, various composite materials, and the like. Furthermore, it can also be used as a transfer sheet when producing an electromagnetic wave shielding film or the like. When the release sheet of the present invention is used as a process film or a transfer sheet, it is used in the process of peeling off from the release sheet various sheet materials formed by coating resin or the like on the release layer side surface of the release sheet. do.

[How to use the release sheet]
The release sheet of the present invention is used in the following forms in various applications.
For example, a case where the release sheet of the present invention is used as a transfer sheet will be described. First, a coating liquid (protective layer coating liquid, adhesive layer coating liquid) for forming a protective layer and an adhesive layer constituting the transfer layer of the transfer sheet on the release layer of the release sheet is prepared. A protective layer coating liquid and an adhesive layer coating liquid are sequentially coated on the release layer of the release sheet, and if necessary, dried by heating to form a transfer sheet. If the applied adhesive layer, which is the outermost layer, is sticky even after drying, another release sheet may be laminated to protect the sticky surface of the adhesive layer. Here, as the component of the protective layer that is in direct contact with the release sheet, for example, thermosetting acrylic resins, epoxy resins and melamine resins are suitable.
The transfer layer (protective layer) of the transfer sheet thus obtained is transferred to the object to be transferred. In order to perform transfer, the target is the cutting process of cutting the transfer sheet to the required size, the peeling process of peeling off another release sheet, the lamination process of laminating on the above object, and the laminated transfer layer (protective layer) A hot press step of hot pressing so as to adhere and fix to an object, a peeling step of peeling off a release sheet, and the like are performed to produce an article having a configuration of "object-adhesive layer-protective layer". Although the adhesive layer and the protective layer are in direct contact here, an optional functional layer may be provided between the adhesive layer and the protective layer.
The operation of performing the transfer includes an operation that should not be peeled off in the process like the cutting process, and the separation between the release sheet and the transfer layer (protective layer) like the hot press process. Included are operations that can change the releasability between layers. The temperature of the hot press treatment in the hot press step is preferably 100 to 240°C, more preferably 130 to 210°C, still more preferably 160 to 180°C. Further, the pressure of the hot press treatment in the hot press step is preferably 0.1 to 10 MPa, more preferably 0.5 to 5 MPa, and still more preferably 1 to 3 MPa. Furthermore, the heat press treatment time in the heat press step is preferably 1 second to 30 minutes, more preferably 1 to 10 minutes, and still more preferably 2 to 8 minutes.

The present invention will be specifically described by the following examples, but the present invention is not limited to the following examples.

[Examples and Comparative Examples]
Release sheets of Examples 1 to 6 and Comparative Examples 1 to 6 were produced by the following procedure.
In addition, each component used in each example and comparative example is as follows.
<(A) + (B) component -1>
Silicone-modified acrylic resin containing melamine resin (solid concentration: 35 mass%, mass ratio of silicone-modified acrylic resin to melamine resin [silicone-modified acrylic resin/melamine resin] = 70/30, product name: X-62- 9088, manufactured by Shin-Etsu Chemical Co., Ltd., silicone modified amount of silicone modified acrylic resin 0.57 mmol / g)
<(A) + (B) component -2>
Silicone-modified acrylic resin containing melamine resin (solid concentration: 35 mass%, mass ratio of silicone-modified acrylic resin to melamine resin [silicone-modified acrylic resin/melamine resin] = 70/30, product name: X-62- 9089, manufactured by Shin-Etsu Chemical Co., Ltd., silicone modified amount of silicone modified acrylic resin 0.11 mmol / g)
<acrylic resin>
Acrylic resin (solid content concentration 48% by mass, mass ratio of stearyl-modified alkyd resin, stearyl-modified acrylic resin, and melamine resin [stearyl-modified alkyd resin/stearyl-modified acrylic resin/melamine resin] = 40/40/20, product name: TF303, manufactured by Showa Denko Materials Company)

<(C) Component>
p-toluenesulfonic acid (solid content concentration 50% by mass)
<(D) component>
Boron nitride particles (average particle size 0.7 μm, trade name UHP-S2, manufactured by Showa Denko KK)

<Example 1>
To a mixed solvent with a mass ratio of toluene and methyl ethyl ketone of 1:1, 8.17 g (A) + (B) component-1 (in terms of solid content) and 3.50 g (A) + (B) component-2 ( 3.75 g of boron nitride particles were added as the component (D) and dispersed at 2,000 rpm for 20 minutes using a disper. At this time, the amount of the mixed solvent was adjusted so that the solid content concentration of the mixed liquid immediately after addition of the component (D) was 20% by mass. Subsequently, 0.33 g (in terms of solid content) of a methanol solution of p-toluenesulfonic acid was added as the component (C) to the above mixed solution, and the mixture was stirred at 1,500 rpm for 5 minutes using a disper to obtain a release agent composition. A coating liquid was prepared.
The obtained coating liquid of the release agent composition was applied to one side of a polyethylene terephthalate film (trade name: PET50A4160, manufactured by Toyobo Co., Ltd., thickness 50 μm) using a Meyer bar, dried and cured at 150° C. for 1 minute. , a release sheet having a release layer having a thickness of 2.0 μm after curing was prepared.

<Example 2>
In Example 1, except that (A) + (B) component -1 was changed to 5.83 g (solid content conversion) and (A) + (B) component -2 was changed to 5.83 g (solid content conversion) A release sheet was prepared in the same manner as in Example 1.

<Example 3>
A release sheet was produced in the same manner as in Example 1, except that the amount of component (D) was changed to 7.50 g.

<Example 4>
In Example 1, (A) + (B) component -1 was changed to 7.58 g (solid content conversion) and (A) + (B) component -2 was changed to 4.08 g (solid content conversion), (D ) A release sheet was prepared in the same manner as in Example 1, except that the component was changed to 7.50 g.

<Example 5>
In Example 1, (A) + (B) component -1 was changed to 7.00 g (solid content conversion) and (A) + (B) component -2 to 4.67 g (solid content conversion), (D ) A release sheet was prepared in the same manner as in Example 1, except that the component was changed to 7.50 g.

<Example 6>
A release sheet was prepared in the same manner as in Example 2, except that the amount of component (D) was changed to 7.50 g.

<Comparative Example 1>
In Example 1, (A) + (B) component -1 was changed to 11.67 g (solid content conversion), (A) + (B) component -2 was changed to 0 parts by mass (not added) A release sheet was produced in the same manner as in Example 1, except for the above.

<Comparative Example 2>
In Example 1, (A) + (B) component-1 was changed to 0 parts by mass (not added), and (A) + (B) component-2 was changed to 11.67 parts by mass. A release sheet was prepared in the same manner as in Example 1.

<Comparative Example 3>
In Example 1, (A) + (B) component -1 was changed to 3.50 g (solid content conversion) and (A) + (B) component -2 was changed to 8.17 g (solid content conversion), (D ) A release sheet was prepared in the same manner as in Example 1, except that the component was changed to 7.50 g.

<Comparative Example 4>
In Example 1, (A) + (B) component -1 was changed to 1.17 g (solid content conversion) and (A) + (B) component -2 was changed to 10.50 g (solid content conversion), (D ) A release sheet was prepared in the same manner as in Example 1, except that the component was changed to 7.50 g.

<Comparative Example 5>
In Example 1, instead of (A) + (B) component-1 and (A) + (B) component-2, 11.67 g (solid content conversion) of acrylic resin was added. A release sheet was prepared in the same manner as above.

<Comparative Example 6>
In Example 1, instead of (A) + (B) component-1 and (A) + (B) component-2, 11.67 g (solid content conversion) of acrylic resin was added, and 7 components (D) were added. A release sheet was prepared in the same manner as in Example 1, except that the weight was changed to 0.50 g.

[evaluation]
The release sheets of Examples 1-6 and Comparative Examples 1-6 were subjected to the following measurements and evaluations.

<Thickness of release layer>
The thickness of the release layer was measured using a spectroscopic ellipsometer (manufactured by JA Woollam Japan Co., Ltd., trade name: Spectroscopic Ellipsometry 2000U).

<Surface roughness Ra>
For the release layers of the release sheets obtained in Examples 1 to 6 and Comparative Examples 1 to 6, a surface roughness measuring machine (product name: SV3000S4, stylus type, manufactured by Mitutoyo Co., Ltd.) was used to measure JIS B 0601- 2013, the arithmetic mean roughness Ra was measured. Table 1 shows the results.
In addition, the measurement conditions are as follows.
(Measurement conditions) Reference length = 2.5 mm, λc = 0.25 mm, λs = 0.008 mm, evaluation length = 10 mm, scanning speed = 1.0 mm/s, range = 800 µm.

<Peel strength before heat press treatment>
Acrylic resin and melamine resin are used as thermosetting resins for the protective layer, each of which is applied on the release layer of the release sheets obtained in Examples 1 to 6 and Comparative Examples 1 to 6, and dried at 160 ° C. for 30 seconds. A film of acrylic resin or melamine resin having a thickness of about 3 μm was formed by heating, and a protective layer was formed on the release layer to obtain a sample.
The obtained sample was fixed to a universal tensile tester (trade name: Autograph AGS-20NX, manufactured by Shimadzu Corporation) and subjected to a tensile speed of 0.3 m / min in a 180 ° direction in accordance with JIS K6854: 1999. The release sheet was peeled from the sample at high speed. The stress required for peeling at this time was defined as the peeling force (mN/50 mm) of the release sheet before the heat press treatment. Table 1 shows the results.
The acrylic resin and melamine resin used as the thermosetting resin are as follows.
<acrylic resin>
Acrylic resin (product name: UC-3000, manufactured by Toagosei Co., Ltd.) / melamine resin (front product name: TF-200, manufactured by Showa Denko Materials Co., Ltd.) / p-toluenesulfonic acid (solid content concentration 50% by mass) , a composition having a compounding ratio (mass ratio) of 0.7/0.3/0.1.
<Melamine resin>
Melamine resin (product name: TF-200, manufactured by Showa Denko Materials Co., Ltd.)/p-toluenesulfonic acid (solid concentration: 50% by mass) is a composition with a compounding ratio (mass ratio) of 1/0.1.

<Peel strength after heat press treatment>
Acrylic resin and melamine resin are used as thermosetting resins for the protective layer, each of which is applied on the release layer of the release sheets obtained in Examples 1 to 6 and Comparative Examples 1 to 6, and dried at 160 ° C. for 30 seconds. Thus, an acrylic resin or melamine resin film having a thickness of about 3 μm was formed to obtain a sample in which a protective layer was formed on the release layer.
Using a pressing machine (trade name: Manual Hydraulic Heating Press 180C, manufactured by Imoto Seisakusho Co., Ltd.), the obtained sample was subjected to heat press treatment under the conditions of 170° C., 2 MPa, and 5 minutes. After that, it is fixed to a universal tensile tester (trade name: Autograph AGS-20NX, manufactured by Shimadzu Corporation), and in accordance with JIS K6854: 1999, at a tensile speed of 0.3 m / min in the direction of 180 °, The release sheet was peeled off from the sample. The stress required for peeling at this time was defined as the peel force (mN/50 mm) of the release sheet after the heat press treatment. Table 1 shows the results.
The acrylic resin and melamine resin used as the thermosetting resin are the same as the thermosetting resin used in the above [Peeling force before hot press treatment].

In addition, each notation in Table 1 is as follows.
· (A) + (B) component-1: Total solid content (g) of component (A) and component (B), solid content mass ratio (A)/(B) = 70/30.
· (A) + (B) component-2: Total solid content (g) of component (A) and component (B), solid content mass ratio (A)/(B) = 70/30.
• Si modification amount (mmol/g): The amount of silicone modification (mmol/g) in the solid content of component (A).
- (C) component: Solid content (g).
• Total solid content (g): the total solid content (g) in the stripping composition.
• Si modification amount (mmol/g) in the composition: The silicone modification amount (mmol/g) of component (A) in the total solid content in the release composition.
*1: Content (parts by mass) of component (C) with respect to 100 parts by mass of component (B) in terms of solid content.
*2: The content (parts by mass) of the component (D) with respect to 100 parts by mass of the resin component.

From Table 1, in Examples 1 to 6, the peel force before the heat press treatment was adjusted to 80 mN/50 mm or more for the protective layer of the acrylic resin, and the peel force after the heat press treatment was 400 mN/50 mm or less. It was found that the excellent effect of being able to adjust to In Examples 1 to 6, the release force of the melamine resin protective layer was adjusted to 150 mN/50 mm or more before the heat press treatment, and the release force after the heat press treatment was adjusted to 450 mN/50 mm or less. It was found that the excellent effect of being able to
On the other hand, in Comparative Examples 1 to 6, in which the amount of silicone modification in the solid content of the silicone-modified acrylic resin (A) did not fall within the specified range, both the acrylic resin and melamine resin protective layers It turned out to be difficult to adjust the release force both before and after the hot press treatment within the desired range.

1A release sheet 10 base material 11 release layer 12 filler

Claims

Having a base material and a release layer formed on the base material,
The release layer is a layer formed from a release agent composition containing a silicone-modified acrylic resin (A), a melamine resin (B), an acid catalyst (C), and a filler (D),
The release sheet, wherein the amount of silicone modification in the solid content of the silicone-modified acrylic resin (A) is 0.3 to 0.5 mmol/g.
The release according to claim 1, wherein the mass ratio (A)/(B) of the silicone-modified acrylic resin (A) and the melamine resin (B) is 50/50 to 95/5 in terms of solid content. sheet.
The release sheet according to claim 1 or 2, wherein the content of the acid catalyst (C) is 0.1 to 20 parts by mass in terms of solid content with respect to 100 parts by mass of the melamine resin (B).
When the resin component is obtained by removing the filler (D) from the total solid of the release agent composition, the content of the filler (D) is 15 to 75 parts by mass with respect to 100 parts by mass of the resin component. The release sheet according to any one of claims 1 to 3.
Amount of silicone modification of the silicone-modified acrylic resin (A) in the total solid content of the silicone-modified acrylic resin (A), the melamine resin (B), the acid catalyst (C), and the filler (D) is 0.18 to 0.40 mmol/g, the release sheet according to any one of claims 1 to 4.
The release sheet according to any one of claims 1 to 5, wherein the filler (D) contains boron nitride particles.