TWI837331B - Peel-off sheet - Google Patents

Abstract

A release sheet is provided, which comprises a release layer and a substrate, wherein the release layer is a cured product of a release agent composition, wherein the release agent composition comprises an acrylic resin (A), an amino resin (B) and a polyolefin (C) having a crosslinking functional group, wherein the content of the component (B) is 15% to 65% by mass in the total content of the components (A), (B) and (C) of 100% by mass, and the content of the component (C) is 55% to 55% by mass in the total content of the components (A), (B) and (C) of 100% by mass.

Description

Peeling film

The present invention relates to a peeling sheet.

Generally speaking, a release sheet has a substrate such as paper, plastic film or polyethylene laminated paper, and a release layer disposed on the substrate. The release layer is formed by, for example, applying a release agent composition containing a reactive compound on the substrate and hardening it. Release sheets are widely used, for example, as protective sheets for adhesive layers of adhesive sheets, step films for making resin sheets, step films for film formation of ceramic green sheets, and step films for making synthetic leather.

As a peeling agent composition for forming a peeling layer, a polysilicone-based peeling agent composition containing a polysilicone compound such as a polysilicone resin, a silicone oil, etc. is widely used. However, the polysilicone compound may migrate to the contact surface with the peeling layer, for example, to the surface of the adhesive layer of the adhesive sheet. In addition, after the migration, it may be slowly vaporized. Therefore, if a peeling sheet having a peeling layer formed of a polysilicone-based peeling agent composition is used in electronic material applications, for example, the polysilicone compound may migrate to the electronic parts, causing corrosion or malfunction of the electronic parts.

Therefore, studies have been conducted on forming a peeling layer without using a silicone-based peeling agent composition. For example, Patent Document 1 describes a peeling sheet having a peeling layer formed of a peeling agent composition, wherein the peeling agent composition contains at least a polyolefin, an isocyanate having three or more isocyanate groups in one molecule, and a polyolefin polyol. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2011-52207

[The problem that the invention wants to solve]

Generally speaking, the optimal value of the peeling force of a peeling sheet varies depending on the application or the type of the laminated object. For example, although a lower peeling force is preferred for easy peeling operation, on the other hand, a higher peeling force is preferred when the retention of the laminated object (fall-off resistance) is prioritized. Therefore, a peeling sheet with an appropriate peeling force is also required, which is not extremely low. In this way, it is required to design a peeling agent that can make the product made using the peeling sheet suitable for the peeling force that is suitable for its utilization form. In addition, the peeling sheet may warp depending on its storage conditions, for example, when stored at high temperature or for a long time. In addition, when the peeling sheets are stacked or stored in a roll, there is a risk that the peeling sheets may stick to each other. Therefore, in addition to good peeling properties, the peeling sheet is also required to have properties of warping resistance and adhesion resistance. In addition, depending on the use of the peeling sheet, for example, in electronic material applications, the peeling sheet is often required to have resistance to organic solvents (solvent resistance).

Therefore, the object of the present invention is to provide a peeling sheet having a peeling layer with good peeling properties, warping resistance, adhesion resistance and solvent resistance. [Means for solving the problem]

The inventors of the present invention have found that a peeling sheet having a peeling layer which is a cured product of a peeling agent composition containing the components (A) to (C) described below and containing the components (B) and (C) in specific amounts can solve the above-mentioned problems.

That is, the present invention relates to the following [1] to [7]. [1] A peeling sheet having a peeling layer and a substrate, the peeling layer being a cured product of a peeling agent composition, the peeling agent composition comprising an acrylic resin (A), an amino resin (B) and a polyolefin (C) having a crosslinking functional group, the content of the component (B) is 15% to 65% in the total content of the components (A), (B) and (C) being 100% by mass, the content of the component (C) is 55% to 55% in the total content of the components (A), (B) and (C) being 100% by mass. [2] The release sheet as described in [1] above, wherein the glass transition temperature (Tg) of the component (A) is 10°C or higher. [3] The release sheet as described in [1] or [2] above, wherein the component (B) is a melamine resin. [4] The release sheet as described in any one of [1] to [3] above, wherein the crosslinking functional group of the component (C) is a hydroxyl group. [5] The release sheet as described in any one of [1] to [4] above, wherein the component (C) is a polybutadiene having a crosslinking functional group or a polyisoprene having a crosslinking functional group. [6] The release sheet as described in any one of [1] to [5] above, wherein the component (C) is a hydrogenated polyolefin having a crosslinking functional group. [7] A peeling sheet as described in any one of [1] to [6] above, wherein the peeling force of the self-adhesive layer during peeling is 500 to 4,000 mN/20 mm. [Effect of the invention]

According to the present invention, a peeling sheet having a peeling layer having good peeling properties, warping resistance, blocking resistance and solvent resistance can be provided.

In this specification, the so-called "solid content" refers to the components contained in the peeling agent composition, excluding the solvent. In addition, in this specification, the retention of the object from the object laminated with the peeling sheet to the peeling operation of the peeling sheet is also called "peeling resistance". In addition, in this specification, the lower limit and upper limit values described in stages for the preferred numerical range (for example, the range of content, etc.) can be independently combined. For example, from the description of "preferably 10 or more, more preferably 30 or more, more preferably 40 or more, then preferably 90 or less, more preferably 80 or less, and more preferably 70 or less", as a suitable range, for example, a range of lower limit values and upper limit values independently selected from the combination of "10 or more and 70 or less", "30 or more and 70 or less", and "40 or more and 80 or less" can be selected. In addition, from the same description, a range can be selected that stipulates only one of the lower limit value or upper limit value of "40 or more" or "70 or less". In addition, for example, the suitable range that can be selected from the description of "preferably 10 or more and 90 or less, more preferably 30 or more and 80 or less, and more preferably 40 or more and 70 or less" and "preferably 10 to 90, more preferably 30 to 80, and more preferably 40 to 70" is also the same. In addition, in the description of a numerical range in this specification, for example, the description of "10 to 90" is synonymous with "10 or more and 90 or less".

[Peeling sheet] The peeling sheet of the present invention has a peeling layer and a substrate. Figure 1 is a schematic cross-sectional view showing a peeling sheet of one embodiment of the present invention. The peeling sheet 1 has a substrate 10 and a peeling layer 11 disposed on the substrate 10. The peeling layer 11 is a cured product of a peeling agent composition comprising an acrylic resin (A), a specific amount of an amino resin (B), and a specific amount of a polyolefin having a crosslinking functional group (C). In one embodiment of the present invention, the peeling sheet may have peeling layers on both sides of the substrate 10 (not shown). In this case, as long as the effect of the present invention is not impaired, at least one of the multiple peeling layers is the peeling layer 11. In the case where the peeling layer 11 is multiple, the composition of the peeling agent composition forming each peeling layer 11 may be the same or different. In addition, the above-mentioned various aspects may be aspects consisting only of the substrate 10 and the peeling layer 11, and other layers such as an easy-to-adhesion layer and an antistatic layer not shown may be provided between the substrate 10 and the peeling layer 11. The peeling layer and the substrate constituting the peeling sheet of the present invention are described below.

<Peeling layer> The peeling layer of the peeling sheet of the present invention is a hardened material formed by a peeling agent composition, wherein the peeling agent composition comprises an acrylic resin (A), an amino resin (B) and a polyolefin (C) having a crosslinking functional group, wherein the content of the aforementioned component (B) is 15% to 65% in the total content of the components (A), (B) and (C) of 100% by mass, and the content of the aforementioned component (C) is 55% to 55% in the total content of the components (A), (B) and (C) of 100% by mass. The following describes the material for forming the peeling layer, i.e., the peeling agent composition. In addition, in the following description, "the content of each component in the stripping agent composition" can also be regarded as "the content of each component in the stripping layer formed by the stripping agent composition". Moreover, the content can also be regarded as a value calculated from the blending amount when each component is blended. In addition, in this specification, the content of each component, the total content, and the ratio of each component are all values converted to solid components.

(Stripping agent composition) The stripping agent composition comprises an acrylic resin (A) (hereinafter, also referred to as "component (A)"), an amino resin (B) (hereinafter, also referred to as "component (B)") and a polyolefin having a crosslinking functional group (C) (hereinafter, also referred to as "component (C)"), wherein the content of the aforementioned component (B) is 15% by mass or more and 65% by mass or less in the total content of the components (A), (B) and (C) (100% by mass), and the content of the aforementioned component (C) is 55% by mass or less in the total content of the components (A), (B) and (C) (100% by mass).

The inventors of the present invention have conducted various studies on the formulation of a peeling layer formed by using a peeling agent composition other than a polysilicone peeling agent composition in order to find a formulation that can solve the above-mentioned problems. As a result, they have found that the formulation of a peeling layer formed by using a peeling agent composition that meets the above-mentioned requirements is an effective formulation, and finally completed the present invention.

The following is a description of the components contained in the peeling agent composition.

[Component (A): Acrylic resin] The aforementioned peeling agent composition contains acrylic resin as component (A). Although the reason is not determined, the aforementioned peeling agent composition, by containing component (A), can form a peeling layer having a peeling force in a range that is difficult to obtain only by the combination of components (B) and (C) described later.

Examples of the aforementioned acrylic resin include polymers containing structural units derived from alkyl (meth)acrylates having a linear or branched alkyl group, polymers containing structural units derived from (meth)acrylates having a cyclic structure, and the like. In this specification, "(meth)acrylate" is used as a term meaning either or both of "acrylate" or "methacrylate". Similarly, "(meth)acrylic group" is used as a term meaning either or both of "acrylic group" or "methacrylic group".

As the aforementioned acrylic resin, a polymer having a structural unit (a1) derived from an alkyl (meth)acrylate (a1') (hereinafter, also referred to as "monomer (a1')") is preferred, and a copolymer having a structural unit (a2) derived from a monomer (a2') containing a functional group (hereinafter, also referred to as "monomer (a2')") together with the structural unit (a1) is more preferred.

The carbon number of the alkyl group possessed by the monomer (a1') is preferably 1 to 3. In addition, the alkyl group possessed by the monomer (a1') may be a linear alkyl group or a branched alkyl group. Examples of the monomer (a1') include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, etc. Such monomers (a1') may be used alone or in combination of two or more.

The functional group possessed by the monomer (a2') can be exemplified by a hydroxyl group, a carboxyl group, an amino group, an epoxy group, etc. That is, as the monomer (a2'), for example, a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an amino group-containing monomer, an epoxy group-containing monomer, etc. can be exemplified. In the case of using such monomers (a2'), they can be used alone or in combination of two or more. As the monomer (a2'), a hydroxyl group-containing monomer and a carboxyl group-containing monomer are preferred, and a hydroxyl group-containing monomer is more preferred.

Examples of monomers containing a hydroxyl group include hydroxy methyl (meth) acrylate, 2-hydroxy ethyl (meth) acrylate, 2-hydroxy propyl (meth) acrylate, 3-hydroxy propyl (meth) acrylate, 2-hydroxy butyl (meth) acrylate, 3-hydroxy butyl (meth) acrylate, 4-hydroxy butyl (meth) acrylate, and other hydroxy alkyl (meth) acrylates; unsaturated alcohols such as vinyl alcohol and allyl alcohol; and the like. Examples of monomers containing a carboxyl group include ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid, citric acid, and their anhydrides; 2-(acryloyloxy)ethyl succinate, 2-carboxyethyl (meth) acrylate, and the like. Examples of monomers containing amino groups include aminoethyl (meth)acrylate, ethylaminoethyl (meth)acrylate, aminopropyl (meth)acrylate, ethylaminopropyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, etc. Examples of monomers containing epoxy groups include epoxypropyl (meth)acrylate, etc.

Furthermore, the aforementioned acrylic resin may also be a copolymer further having a structural unit (a3) derived from another monomer (a3') other than the monomers (a1') and (a2'). Examples of the monomer (a3') include halogenated olefins such as vinyl chloride and vinylidene chloride; (meth)acrylates having a ring structure such as cyclohexyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, isoborneol (meth)acrylate, adamantyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and imide (meth)acrylate; styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, (meth)acrylamide, (meth)acrylonitrile, (meth)acryloylmorpholine, and N-vinylpyrrolidone. When using these monomers (a3'), they may be used alone or in combination of two or more.

In addition, in the aforementioned acrylic resin, the content of each of the structural units (a1), (a2) and (a3) in the total structural units (100 mass %) of the acrylic resin can be adjusted, for example, by adjusting the blending amount of each of the monomers (a1'), (a2') and (a3'). For example, it is preferred to appropriately adjust the blending amount of each of the monomers (a1'), (a2') and (a3') so as to satisfy the suitable range of the glass transition temperature (Tg) and/or the suitable range of the hydroxyl group value described later.

The glass transition temperature (Tg) of the component (A) is preferably 10° C. or higher, more preferably 15° C. or higher, and even more preferably 20° C. or higher, from the viewpoint of improving the blocking resistance of the obtained peeling sheet. The upper limit of the glass transition temperature (Tg) is not particularly limited as long as the effect of the present invention is not impaired, but is preferably 150° C., for example. The glass transition temperature (Tg) can be measured, for example, by the method described in the examples below.

For example, when obtaining an acrylic resin having a desired glass transition temperature (Tg), a monomer whose homopolymer obtained when polymerized alone has a glass transition temperature (Tg) higher than the desired glass transition temperature (Tg) and a monomer whose homopolymer obtained when polymerized alone has a glass transition temperature (Tg) lower than the desired glass transition temperature (Tg) are selected. Then, in order to obtain a copolymer having a desired glass transition temperature (Tg), the blending amount of each monomer is appropriately adjusted with reference to the glass transition temperature (Tg) of the homopolymer obtained when each monomer is polymerized alone, thereby obtaining an acrylic resin having a desired glass transition temperature (Tg).

In addition, the hydroxyl value of component (A) is preferably 5 mgKOH/g or more, more preferably 8 mgKOH/g or more, and even more preferably 10 mgKOH/g or more from the viewpoint of improving the solvent resistance of the obtained peeling sheet. The upper limit of the hydroxyl value is not particularly limited as long as it does not impair the effect of the present invention, but for example, it is preferably 200 mgKOH/g, more preferably 150 mgKOH/g, and even more preferably 100 mgKOH/g. The value of the hydroxyl value can also be measured, for example, according to the method described in JIS K0070-1992. Furthermore, in the case of obtaining an acrylic resin having a desired hydroxyl value, for example, by appropriately adjusting the blending amount of the aforementioned hydroxyl group-containing monomer, an acrylic resin having a desired hydroxyl value can be obtained.

In addition, the mass average molecular weight (Mw) of component (A) is preferably 5,000 to 100,000, more preferably 8,000 to 80,000, and even more preferably 10,000 to 50,000. The mass average molecular weight (Mw) means the value converted to polystyrene measured by gel permeation chromatography (GPC). Component (A) can be used alone or in combination of two or more.

In one aspect of the present invention, from the viewpoint of improving the peeling property of the release layer, the content of component (A) is preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, based on 100% by mass of the total content of component (A), component (B) and component (C). Furthermore, from the viewpoint of solubility in a dilute solvent during film formation and from the viewpoint of exhibiting a peeling force with an excellent balance between easy peeling property and peeling resistance of the release layer, the content of component (A) is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 65% by mass or less, based on 100% by mass of the total content of component (A), component (B) and component (C).

[Component (B): amino resin] The stripper composition contains an amino resin as component (B) in an amount of 15% to 65% by mass out of the total content of component (A), component (B) and component (C) of 100% by mass. In this specification, the term "amino resin" refers to a general term for compounds obtained by the reaction of compounds having an amino group such as melamine, urea, aniline, guanamine, etc. with aldehydes such as formaldehyde and acetaldehyde. As examples of amino resins, melamine resins; urea resins (same as urea resins); aniline resins; guanamine resins; etc. can be cited. Among them, melamine resin is preferred from the viewpoint of the curability of the stripping agent composition and the improvement of the solvent resistance of the obtained stripping layer. As the melamine resin, preferably one or more selected from the group consisting of hydroxymethylated melamine resin, iminohydroxymethylated melamine resin, methylated melamine resin, ethylated melamine resin, propylated melamine resin, butylated melamine resin, hexylated melamine resin and octylated melamine resin can be cited, and more preferably one or more selected from the group consisting of hydroxymethylated melamine resin, iminohydroxymethylated melamine resin and methylated melamine resin. Among these, methylated melamine resin is more preferred from the viewpoint of the low-temperature curing property of the releasable composition. Component (B) may be used alone or in combination of two or more.

In the aforementioned peeling agent composition, when the content of component (B) exceeds 65% by mass out of the total content of component (A), component (B) and component (C) of 100% by mass, the warp resistance of the obtained peeling sheet deteriorates due to the condensation reaction of the amino resin. On the other hand, when the content of component (B) is less than 15% by mass out of the total content of component (A), component (B) and component (C) of 100% by mass, the solvent resistance of the obtained peeling sheet deteriorates due to the condensation reaction of the amino resin. Therefore, from the viewpoint of having both good warp resistance and good solvent resistance, the content of component (B) is preferably 16 mass % or more, more preferably 18 mass % or more, and further preferably 20 mass % or more, and is preferably 60 mass % or less, more preferably 55 mass % or less, and further preferably 45 mass % or less, based on 100 mass % of the total content of component (A), component (B) and component (C).

[Component (C): Polyolefin (C) having a crosslinking functional group] The aforementioned stripping agent composition, as component (C), contains a polyolefin having a crosslinking functional group in an amount of 55% by mass or less out of 100% by mass of the total content of components (A), (B) and (C). In this specification, the term "polyolefin" is used to mean a polymer obtained by polymerization of dienes such as butadiene and isoprene as monomer units. In addition, in this specification, the term "crosslinking functional group" means a functional group that reacts with at least component (B) that serves as a crosslinking agent.

Examples of the aforementioned polyolefin include polyethylene, polypropylene, ethylene-α-olefin copolymers obtained by polymerizing at least two olefins selected from the group consisting of ethylene, propylene, and α-olefins having a carbon number of 4 to 20, polybutadiene, polyisoprene, and various other polyolefins. Among these, polybutadiene or polyisoprene is preferred from the viewpoint of obtaining a release layer having good release properties. Furthermore, although the peeling force required for the peeling sheet varies depending on the purpose of the peeling sheet or the object to be laminated on the peeling layer, for example, when a higher peeling force is required within the range of the peeling force of the peeling layer obtained by the combination of components (A) to (C), polybutadiene is more preferred, and when a lower peeling force is required, polyisoprene is more preferred.

Examples of the crosslinking functional group possessed by component (C) include hydroxyl, carboxyl, epoxy, amine, isocyanate, thiol, and vinyl groups. Among these, the crosslinking functional group is preferably a hydroxyl group from the viewpoint of being more reactive with component (B). In addition, although component (C) only needs to have at least one crosslinking functional group, it is preferred to have two or more crosslinking functional groups. In the case where component (C) has two or more crosslinking functional groups, these functional groups may be the same or different from each other, but it is preferred that they are the same.

The position of the crosslinking functional group possessed by component (C) is not particularly limited as long as it is a position where the crosslinking functional group can react with component (B). Here, in one aspect of the present invention, it is preferred that the crosslinking functional group be present at at least one end of the molecular chain constituting the polymer skeleton of component (C). From the viewpoint of lengthening the distance between the crosslinking points and forming a peeling layer with better peeling properties, it is preferred that the crosslinking functional group be present at both ends of the molecular chain constituting the polymer skeleton of component (C). It is further preferred that the crosslinking functional group be present only at both ends of the main chain constituting the polymer skeleton of component (C).

In addition, component (C) is preferably a hydrogenated polyolefin from the perspective of the stability of the peeling force over time. The degree of hydrogenation of component (C) may be partial hydrogenation or complete hydrogenation, but from the perspective of improving the chemical stability of the peeling force of the peeling layer, a partially hydrogenated product with a low residual rate of unsaturated bonds such as vinyl groups is preferred, and a completely hydrogenated product is more preferred. Therefore, from the same perspective, component (C) is preferably one with a low bromine value. The lower the bromine value, the lower the residual rate of unsaturated bonds including unsaturated bonds in component (C), and the less susceptible to chemical changes such as oxidation, the better the stability of the peeling force of the peeling layer over time. For example, in one embodiment of the present invention, the bromine value of component (C) is preferably 100 g/100 g or less, more preferably 20 g/100 g or less, further preferably 10 g/100 g or less, and further preferably 8 g/100 g or less. The bromine value is a value measured in accordance with JIS K 2605-1996.

The number average molecular weight ( _Mn ) of component (C) is preferably 1,000 to 30,000, more preferably 1,000 to 20,000, further preferably 1,000 to 10,000, and further preferably 1,000 to 5,000. In this specification, the number average molecular weight (Mn) is a value converted to standard polystyrene measured by gel permeation chromatography (GPC), for example, by the method described in the examples described below. Component (C) may be used alone or in combination of two or more.

In the aforementioned peeling agent composition, when the content of component (C) exceeds 55% by mass out of the total content of component (A), component (B) and component (C) (100% by mass), the blocking resistance of the obtained peeling sheet deteriorates. Therefore, from the viewpoint of improving the blocking resistance, the content of component (C) is preferably 45% by mass or less, more preferably 35% by mass or less, and even more preferably 25% by mass or less out of the total content of component (A), component (B) and component (C) (100% by mass). Furthermore, from the viewpoint of obtaining good releasability as a release layer, the content of component (C) is preferably 5 mass % or more, more preferably 10 mass % or more, and even more preferably 15 mass % or more, based on 100 mass % of the total content of component (A), component (B) and component (C).

In one aspect of the present invention, the total content of component (A), component (B) and component (C) in the stripping agent composition is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on the total amount of the stripping agent composition (solid content 100% by mass).

In one aspect of the present invention, the content ratio (A/B) of component (A) to component (B) is preferably 15/85 to 85/15 in terms of mass ratio from the viewpoint of obtaining good peeling force within a range not impairing the effect of the present invention. Then, for example, when polybutadiene is used as the polyolefin of component (C), from the viewpoint of more easily obtaining the effect of the present invention, it is more preferably 40/60 to 80/20, more preferably 55/45 to 80/20, and even more preferably 65/35 to 78/22.

In one aspect of the present invention, the content ratio (A/C) of component (A) to component (C) is preferably 36/64 to 96/4, more preferably 37/63 to 95/5, by mass ratio. For example, when polybutadiene is used as the polyolefin of component (C), from the viewpoint of more easily obtaining the effect of the present invention, it is more preferably 40/60 to 95/5, more preferably 60/40 to 95/5, and even more preferably 70/30 to 80/20.

[Acid Catalyst] In one aspect of the present invention, the stripping agent composition may further include an acid catalyst. By using an acid catalyst, the crosslinking reaction between component (A) and component (B) and/or the crosslinking reaction between component (A) and component (C), and the crosslinking reactivity between component (B) and component (C) are enhanced, and the time stability of the stripping force of the stripping layer can be more easily enhanced. As an acid catalyst, there is no particular limitation, but organic acid catalysts such as p-toluenesulfonic acid, methanesulfonic acid, and alkyl phosphate are suitable. The above acid catalysts may be used alone or in combination of two or more. The amount of the acid catalyst used is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, relative to 100 parts by mass of the total amount of components (A), (B) and (C).

[Other additives] In one embodiment of the present invention, the stripping agent composition may contain other additives other than the above-mentioned components (A), (B) and (C) and the acid catalyst as needed, within the scope of not impairing the effect of the present invention. As such additives, various additives such as antioxidants, ultraviolet absorbers, inorganic or organic fillers, antistatic agents, surfactants, photoinitiators, light stabilizers, etc. can be cited.

[Polysilicone] In one aspect of the present invention, the aforementioned stripping agent composition preferably does not substantially contain polysilicone. If a stripping sheet having a stripping agent layer formed of a stripping agent composition containing polysilicone is used, for example, there is a possibility that the polysilicone may migrate into an adhesive layer to which the polysilicone is attached and hinder the original performance of the adhesive layer. Or, due to the aforementioned stripping layer, the polysilicone may migrate directly or through the aforementioned adhesive layer to a substance (e.g., a manufacturing machine) that the stripping sheet contacts or an object to which the aforementioned adhesive layer is attached, thereby causing corrosion or malfunction of the object. From such a viewpoint, in one aspect of the present invention, the content of the polysilicone compound in the stripping agent composition is preferably less than 5.0 mass %, more preferably less than 2.0 mass %, further preferably less than 1.0 mass %, further preferably less than 0.1 mass %, and further preferably less than 0.01 mass %, based on the total amount of the stripping agent composition (solid content 100 mass %).

[Isocyanate compound] In one aspect of the present invention, the stripping agent composition preferably contains substantially no isocyanate compound from the viewpoint of solvent resistance. In one aspect of the present invention, the content of the isocyanate compound in the stripping agent composition is preferably less than 1.0% by mass, more preferably less than 0.1% by mass, still more preferably less than 0.01% by mass, and still more preferably less than 0.001% by mass, based on the total amount of the stripping agent composition (100% by mass of solid content).

[Diluent solvent] In one aspect of the present invention, from the viewpoint of improving the coating property on the substrate, the stripper composition can also be made into a solution by adding a diluent solvent to the above-mentioned components. The diluent solvent can be selected from organic solvents that have good solubility for the above-mentioned components (A), (B) and (C). As such an organic solvent, for example, toluene, xylene, heptane, octane, methanol, ethanol, isopropanol, isobutanol, n-butanol, ethyl acetate, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, etc. These can be used alone or in combination of two or more. In addition, the organic solvent used as the diluting solvent may be the organic solvent used when synthesizing the aforementioned components (A), (B) and (C). In order to evenly apply the stripping agent composition, the organic solvent used when synthesizing the aforementioned components (A), (B) and (C) and/or one or more organic solvents other than the organic solvent may be added.

The amount of the diluent solvent may be appropriately selected so that the stripper composition has an appropriate viscosity when applied. Specifically, the solid component concentration contained in the solution of the stripper composition is preferably adjusted to a range of 0.1 to 15% by mass, more preferably 0.2 to 10% by mass, and even more preferably 0.5 to 5% by mass.

The thickness of the peeling layer is not particularly limited, but is preferably 25 to 1,000 nm, more preferably 50 to 500 nm. If the thickness of the peeling layer is 25 nm or more, the variation in peeling force due to the variation in the coating amount can be suppressed. If the thickness of the peeling layer is 1,000 nm or less, the curability of the coating film of the peeling agent composition can be improved. The thickness of the peeling layer is measured, for example, by the method described in the embodiment described later.

<Base material> The base material used for the release sheet of the present invention may be, for example, high-quality paper, clay-coated paper, cast paper, kraft paper, etc., laminated paper and synthetic paper sheets obtained by laminating thermoplastic resins such as polyethylene resin on these papers, polyolefin resins such as polyethylene resin and polypropylene resin; polyester resins such as polybutylene terephthalate resin, polyethylene terephthalate resin, polyethylene naphthalate resin; polyetherimide resin; acetate resin; polystyrene resin; sheets of synthetic resins such as vinyl chloride resin, etc. The base material may be a single layer or a multi-layer of two or more layers of the same or different types. The thickness of the substrate is not particularly limited, but is preferably 10 to 300 μm, more preferably 20 to 200 μm. If the thickness of the substrate is 10 to 300 μm, for example, an adhesive sheet made of a peeling sheet can be given toughness or strength suitable for processing such as printing, cutting, and bonding.

Furthermore, when synthetic resin is used as a substrate, the surface of the substrate where the peeling layer is provided may be subjected to surface treatment by oxidation or embossing as desired in order to improve the adhesion between the substrate and the peeling layer. As an oxidation method, examples include corona discharge surface treatment, chromic acid surface treatment (wet), flame surface treatment, hot air surface treatment, ozone/ultraviolet irradiation surface treatment, etc. Also, as an embossing method, examples include sandblasting and solvent treatment. Although these surface treatment methods are appropriately selected depending on the type of substrate, in general, from the perspective of effect and operability, it is better to use the corona discharge surface treatment method. Also, primer treatment may be applied.

The peeling sheet of the present invention can also be embossed on the side of the peeling layer to form a concave-convex surface of the peeling sheet. In addition, the peeling sheet of the present invention can also be provided with other layers such as an easy-adhesion layer and an anti-static layer between the substrate and the peeling layer. By providing the peeling sheet with an easy-adhesion layer, the peeling layer can be effectively prevented from falling off the peeling sheet.

The easy-adhesion layer is usually formed by coating an easy-adhesion coating agent on the surface of the release layer side of the substrate. Examples of the easy-adhesion coating agent include polyester resins, urethane resins, acrylic resins, melamine resins, and resins containing Resins containing oxazoline groups, resins containing carbodiimide groups, resins containing epoxy groups, resins containing isocyanate groups, and copolymers thereof, and coating agents containing natural rubber or synthetic rubber as the main component, etc. These resins may be used alone or in combination of two different types. In addition, in order to improve the coating properties of the easy-adhesion coating agent on the surface of the substrate and the adhesion between the substrate and the easy-adhesion layer, the surface of the substrate on which the easy-adhesion coating agent is applied may be subjected to surface treatment such as chemical treatment or discharge treatment.

The thickness of the easy-adhesion layer is preferably 50 nm to 5 μm, more preferably 100 nm to 1 μm. When the thickness is 50 nm or more, the effect of the easy-adhesion layer can be well obtained. When the thickness is 5 μm or less, the surface of the easy-adhesion layer opposite to the substrate has good slip properties, and the workability of coating the stripping agent composition on the easy-adhesion layer becomes good.

Generally speaking, the preferred value of the peeling force of a peeling sheet varies depending on the application or the type of the laminated object. In some cases, a lower peeling force is preferred for a smooth peeling operation, or a higher peeling force is preferred for improved peeling resistance. In one embodiment of the present invention, the peeling force of the peeling layer shown by the peeling sheet is preferably 500~4,000mN/20mm, more preferably 1,000~3,950mN/20mm, and even more preferably 2,500~3,900mN/20mm or more. The aforementioned peeling force value is a value measured by the method described in the embodiment described below.

[Use of release sheet] The release sheet of the present invention can be used as a protective sheet of various adhesive bodies such as adhesive sheets, for example, it can be used on the adhesive layer side of an adhesive sheet having a substrate and an adhesive layer provided on one side of the substrate. In addition, it can also be used as a step film when producing various resin sheets, ceramic green sheets, synthetic leather, various composite materials, etc. When used as a step film, it is used in the step of peeling off various sheet materials formed by casting, coating, etc. of resin, ceramic slurry, etc. on the surface of the release layer side of the release sheet from the release sheet. In addition, the peeling sheet of the present invention can also be used in electronic devices because the peeling layer is formed by a non-silicone peeling agent composition. For example, in the manufacturing process of electronic parts such as relays, various switches, connectors, motors, hard disks, etc., the peeling sheet can be used as an adhesive sheet for temporary fixation during assembly of electronic parts or for marking the content of parts.

[Manufacturing method of peeling sheet] The peeling sheet of the present invention can be manufactured, for example, by coating the aforementioned peeling agent composition on at least one side of a substrate, and performing a heat treatment to react the components (A) to (C) to form a hardened material as a peeling layer. The peeling agent composition, as described above, can also be in the form of a solution diluted by a diluting solvent.

The heat treatment temperature is preferably 100-170°C, more preferably 130-160°C. In addition, the heat treatment time is not particularly limited, but is preferably 30 seconds to 5 minutes.

Examples of the method for applying the stripping agent composition include gravure coating, rod coating, spray coating, rotary coating, air knife coating, roll coating, doctor blade coating, gate roll coating, and die coating.

The coating thickness of the stripping agent composition is preferably adjusted so that the thickness of the resulting stripping layer is within the aforementioned range. [Example]

Although the present invention is specifically described by the following embodiments, the present invention is not limited to the following embodiments.

The physical property values in the following Examples and Comparative Examples are values measured by the following methods.

[Thickness of peeling layer] The thickness of the peeling layer was measured using a spectroscopic elliptical polarimeter (manufactured by J.A. Woollam Japan Co., Ltd., trade name "Spectroscopic Elliptical Polarimeter 2000U").

[Glass transition temperature (Tg)] The glass transition temperature (Tg) of acrylic resin was measured by heating from 30°C to 200°C at a rate of 10°C/min using a differential scanning calorimeter (manufactured by TA Instruments Japan Co., Ltd., product name "DSC Q2000").

[Bromine value] The value measured in accordance with JIS K 2605-1996 is used.

[Mass average molecular weight (Mw), number average molecular weight (Mn)] The mass average molecular weight (Mw) of acrylic resin and the number average molecular weight (Mn) of polyolefin having crosslinking functional groups use the following values: measured using a gel permeation chromatography (GPC) device (manufactured by Tosoh Co., Ltd., product name "HLC-8320") under the following conditions, and converted into the value of the number average molecular weight of standard polystyrene. (Measurement conditions) ・Measurement sample: tetrahydrofuran solution with a sample concentration of 1 mass % ・Column: 2 "TSK gel Super HM-H" and 1 "TSK gel Super H2000" (both manufactured by Tosoh Co., Ltd.) connected in order from the upstream ・Column temperature: 40°C ・Developing solvent: tetrahydrofuran ・Flow rate: 0.60 mL/min ・Detector: Differential refractometer (RI detector)

[Examples and Comparative Examples] The peeling sheets of Examples 1 to 9 and Comparative Examples 1 to 5 were prepared by the following procedure. In addition, in the following description, unless otherwise specified, the value of "weight parts" is the value converted to solid content.

<Example 1> To 40 parts by weight of component (A) acrylic resin (manufactured by DIC Corporation, product name "ACRYDIC (registered trademark) A-817", glass transition temperature (Tg) = 95°C, hydroxyl value = 60 mgKOH/g, mass average molecular weight = 20,000), methylated melamine resin (Allnex) (component (B)) was added. Japan Co., Ltd., product name "CYMEL (registered trademark)", grade "303LF") 40 parts by mass, and component (C) of hydrogenated polybutadiene modified with hydroxyl groups at both ends (Nippon Soda Co., Ltd., product name "NISSO-PB (registered trademark)", grade "GI-2000", number average molecular weight = 2,000, bromine value = 8g/100g) 20 parts by mass, and further, with respect to the total of 100 parts by mass of components (A), (B) and (C), 3.0 parts by mass of p-toluenesulfonic acid as an acid catalyst was added to prepare a stripping agent composition. The obtained peeling composition was diluted to a solid content concentration of 4.3 mass % using a mixed solvent of toluene and methyl ethyl ketone (toluene:methyl ethyl ketone=6:4 (mass ratio)) to obtain a coating liquid of the peeling agent composition. The obtained coating liquid of the peeling composition was applied to one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Co., Ltd., product name "DIAFOIL (registered trademark)", grade "T-100") with a thickness of 50 μm using a Meyer bar to form a coating film. The coating film was cured by drying at 150°C for 1 minute to form a peeling layer with a thickness of 200 nm to obtain a peeling sheet.

<Examples 2, 3, 8 and 9> Except that the blending amounts of components (A), (B) and (C) were changed to the amounts shown in Table 1 below, the same procedures as in Example 1 were followed to obtain respective peeling sheets.

<Example 4> Except that the acrylic resin of component (A) was changed to an acrylic resin manufactured by Mitsui Chemicals, Inc. (product name "OLESTER (registered trademark)", grade "Q-828", glass transition temperature (Tg) = 135°C, hydroxyl value = 25 mgKOH/g, mass average molecular weight = 16,500), the same procedure as in Example 1 was followed to obtain a release sheet.

<Example 5> Except that the acrylic resin of component (A) was changed to an acrylic resin manufactured by DIC Corporation (product name "ACRYDIC (registered trademark) A-811-BE", glass transition temperature (Tg) = 20°C, hydroxyl value = 35 mgKOH/g, mass average molecular weight = 25,000), the same procedure as in Example 1 was followed to obtain a release sheet.

<Example 6> Except that the acrylic resin of component (A) was changed to an acrylic resin manufactured by DIC Corporation (product name "ACRYDIC (registered trademark) WMU-504", glass transition temperature (Tg) = 60°C, hydroxyl value = 95 mgKOH/g, mass average molecular weight = 17,000), the same procedure as in Example 1 was followed to obtain a release sheet.

<Example 7> Except that component (C) was changed to hydrogenated polyisoprene with hydroxyl groups at both ends (manufactured by Idemitsu Kosan Co., Ltd., product name "EPOL (registered trademark)", number average molecular weight = 2,500, bromine value = 5g/100g), the same procedure as in Example 1 was followed to obtain a release sheet.

<Comparative Examples 1 to 3> Except that component (A) was not used and the blending amounts of components (B) and (C) were changed to the amounts shown in Table 1 below, the same procedures as in Example 1 were followed to obtain various peeling sheets.

<Comparative Examples 4 and 5> Except that the blending amounts of components (A), (B) and (C) were changed to the amounts shown in Table 1 below, the same procedures as in Example 1 were followed to obtain a peeling sheet.

The following measurements and evaluations were performed on the peeled sheets of Examples 1 to 9 and Comparative Examples 1 to 5.

[Peeling force measurement] A 20 mm wide polyester adhesive tape (manufactured by Nitto Denko Co., Ltd., product number "No.31B") was attached to the peeling layer of the peeling sheet obtained in each embodiment and each comparative example using a 2 kg roller to prepare a sample for peeling force measurement. After 30 minutes of attachment, the obtained sample was fixed on a universal tensile testing machine (manufactured by Shimadzu Corporation, product name "Autograph (registered trademark)", model "AGS-20NX"), and the peeling force (mN/20mm) of the peeling sheet was measured by peeling the peeling layer from the adhesive tape in the 180° direction at a tensile speed of 0.3m/min according to JIS K6854-2:1999. The results are shown in Table 1.

[Evaluation of warp resistance] In each embodiment and each comparative example, evaluation samples were prepared in such a way that the thickness of the peeling layer became 1μm. From the obtained evaluation samples, test pieces of 10cm in length and 10cm in width were cut and stored at 120°C for 24 hours. After storage for 24 hours, the test pieces were placed on a horizontal table, and the floating of the four corners of the test pieces was evaluated according to the following criteria. The results are shown in Table 1. A: The average value of the distance that the four corners floated from the table is less than 3mm. B: The average value of the distance that the four corners floated from the table is more than 3mm and less than 5mm. C: The average value of the distance that the four corners floated from the table is more than 5mm.

[Evaluation of blocking resistance] Ten test pieces of 10 cm in length and 10 cm in width were cut from the peeled sheets obtained from each embodiment and each comparative example. The ten test pieces were laminated and pressed for 24 hours at 2 MPa and 40°C using a hot press. After pressing, the state of blocking was visually confirmed and evaluated according to the following criteria. The results are shown in Table 1. A: The appearance of the laminated sheet after pressing maintained the same haze as before pressing, and no blocking was observed. B: The appearance of the laminated sheet after pressing had partial haze disappearance, indicating slight blocking. C: The appearance of the laminated sheet after pressing had full haze disappearance, indicating blocking.

[Evaluation of solvent resistance] On the release layer of the release sheet obtained in each example and each comparative example, a nonwoven fabric impregnated with methyl ethyl ketone (produced by Asahi Kasei Co., Ltd., trade name "BEMCOT (registered trademark)") was placed and rubbed 5 times from the top with a load of 100g. The surface of the release layer was visually observed and evaluated according to the following criteria. The results are shown in Table 1. A: No change was observed on the surface of the release layer. B: Although whitening was observed on the surface of the release layer, the release layer did not completely fall off. C: The release layer completely fell off.

As shown in Table 1, it was confirmed that the peeling sheets of Examples 1 to 9 having a peeling layer of a cured product of a peeling agent composition comprising components (A) to (C), wherein the content of the component (B) is 15 mass % to 65 mass % in the total content of the components (A), (B) and (C) is 100 mass %, and the content of the component (C) is 55 mass % or less in the total content of the components (A), (B) and (C) is 100 mass %, compared with the peeling sheets described in Comparative Examples 1 to 3 having a peeling layer of a cured product of a peeling agent composition not containing the component (A). The peeling sheet, the peeling sheet described in Comparative Example 4 having a peeling layer of a cured product of a peeling agent composition containing component (B) at a content of less than 15% by mass in the total content of component (A), component (B) and component (C) at a content of 100% by mass, and the peeling sheet described in Comparative Example 5 having a peeling layer of a cured product of a peeling agent composition containing component (B) at a content of more than 65% by mass in the total content of component (A), component (B) and component (C) at a content of 100% by mass, can be adjusted to a peeling force that has been difficult to obtain in the past, and at the same time, any of the properties of warping resistance, blocking resistance and solvent resistance are also good. Furthermore, it was confirmed that in the peeling sheets described in Comparative Examples 1 to 3, even when the blending ratio of components (B) and (C) was changed, the peeling force could only be adjusted within a certain peeling force range. Furthermore, it was confirmed that the peeling sheets of Comparative Examples 1 and 5, in which the content of component (B) exceeded 65% by mass in the total content of components (A), components (B) and components (C) of 100% by mass, had poor warping resistance. On the other hand, it was confirmed that the peeling sheet of Comparative Example 4, in which the content of component (B) was less than 15% by mass in the total content of components (A), components (B) and components (C) of 100% by mass, had poor solvent resistance. Furthermore, it was confirmed that the peeling sheets of Comparative Examples 2 and 3, in which the content of component (C) exceeded 55% by mass in the total content of component (A), component (B) and component (C) of 100% by mass, had poor anti-blocking properties. [Industrial Applicability]

The release sheet of the present invention can be used as a protective sheet for various adhesives such as adhesive sheets, and can also be used as a step film when manufacturing various resin sheets, ceramic green sheets, synthetic leather, various composite materials, etc. In addition, since the release layer of the release sheet of the present invention is formed by a non-polysilicone release agent composition, it can also be used as a release sheet for temporary fixation during assembly of electronic parts or as a release sheet for marking the content of parts in the manufacturing process of electronic parts.

1: Peeling film 10: Base material 11: Peeling layer

[Fig. 1] A schematic cross-sectional view of a peeling sheet according to one embodiment of the present invention.

1: Peel off the film

10: Base material

11: Peeling layer

Claims (7)

A peeling sheet having a peeling layer and a substrate, wherein the peeling layer is a cured product of a peeling agent composition, wherein the peeling agent composition comprises an acrylic resin (A), an amino resin (B) and a polyolefin (C) having a crosslinking functional group, wherein the content of the component (B) is 15% to 65% in the total content of the components (A), (B) and (C) of 100% by mass, and the content of the component (C) is 55% to 55% in the total content of the components (A), (B) and (C) of 100% by mass. As in claim 1, the peeling sheet, wherein the glass transition temperature (Tg) of the aforementioned component (A) is above 10°C. For example, the peeling sheet of claim 1 or 2, wherein the aforementioned component (B) is melamine resin. For the release sheet of claim 1 or 2, the cross-linking functional group of the aforementioned component (C) is a hydroxyl group. For example, the peeling sheet of claim 1 or 2, wherein the aforementioned component (C) is polybutadiene having a cross-linking functional group or polyisoprene having a cross-linking functional group. The peeling sheet of claim 1 or 2, wherein the aforementioned component (C) is a hydrogenated polyolefin having a cross-linking functional group. For the peeling sheet in claim 1 or 2, the peeling force of the self-adhesive layer when peeling off is 500~4,000mN/20mm.

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