Release film

Abstract

The purpose of the present invention is to provide a release film that can reduce or suppress the occurrence of cissing. A release film according to the present invention includes a base film and a release layer. The release layer is a layer obtained by curing a silicone composition. The silicone composition contains: a polysiloxane A containing two or more alkenyl groups per molecule; a polysiloxane B containing two or more hydrosilyl groups per molecule; and a polyether-modified silicone. The polysiloxane A and / or the polysiloxane B contains an aryl group. A phenyl group can be listed as one example of the aryl group.

Description

Release film

[0001] This invention relates to a release film.

[0002] Traditionally, release films, which consist of a polyester film and a release layer, have been used in a variety of applications. For example, they are used not only for molding ceramic green sheets, but also in the manufacture of adhesive sheets, cover films, polymer films, and optical lenses.

[0003] Depending on the application of the release film, various resins are used for the release layer. In applications where easy release is required, silicone resin is often used. A release layer using silicone resin, i.e., a silicone release layer, can be formed, for example, by crosslinking a silicone resin having alkenyl groups with a silicone crosslinking agent having hydrosilyl groups.

[0004] When a liquid fluid (such as a ceramic slurry or a liquid composition for polymer film formation) is applied to a silicone release layer, the edges of the applied fluid may partially recede, resulting in a phenomenon called "repellency," where the fluid distribution becomes uneven. In addition, pinholes may occur. Repellency and pinholes lead to a decrease in yield and defect rate.

[0005] To suppress the occurrence of repellency, release films have been proposed that use other resins (such as alkyd resins or acrylic resins) as the release layer instead of the main component, silicone resin (see Patent Documents 1 and 2). However, such release films tend to have excessively heavy peeling force (i.e., excessively large peeling force), and therefore, it must be said that such release films have limitations in their range of applications.

[0006] Patent No. 5361589 Patent No. 5191220

[0007] The present invention aims to provide a release film that can reduce or suppress the occurrence of repellency.

[0008] To solve this problem, the present invention has the configuration of the following [1] (hereinafter sometimes referred to as "item 1"): [1] A release film comprising a base film and a release layer, wherein the release layer is a layer formed by curing a silicone composition, the silicone composition comprises a polysiloxane A containing two or more alkenyl groups in its molecule, a polysiloxane B containing two or more hydrosilyl groups in its molecule, and a polyether-modified silicone, and at least one of the polysiloxane A and the polysiloxane B contains an aryl group.

[0009] According to [1], since the silicone composition of the release layer contains polyether-modified silicone, the water adhesion energy (i.e., the adhesion energy determined by measuring the sliding angle using water) can be improved, and therefore, the occurrence of repulsion when coating a liquid fluid onto a release film can be reduced or suppressed. The improvement in water adhesion energy is thought to be due to the disruption of the arrangement of polysiloxane organic groups (e.g., methyl groups) on the surface of the release layer by the polyether-modified silicone. The improvement in water adhesion energy is also thought to be due to the hydrophilicity of the polyether groups of the polyether-modified silicone.

[0010] Furthermore, since at least one of polysiloxane A and polysiloxane B contains an aryl group, the water adhesion energy can be further improved, and therefore, the occurrence of repelling when coating a liquid fluid onto a release film can be further reduced or suppressed. The improvement in water adhesion energy is thought to be because the aryl group further disrupts the arrangement of the organic groups (e.g., methyl groups) of the polysiloxane on the surface of the release layer.

[0011] The present invention prefers the following configurations [2] to

[13] (hereinafter, these may be referred to as "item 2", "item 3", etc.): [2] The release film according to [1], wherein the content of the polyether-modified silicone in the release layer is 3% by mass or more and 35% by mass or less. [3] The release film according to [1] or [2], wherein the polysiloxane A contains the aryl group. [4] The release film according to any one of [1] to [3], wherein the aryl group is a phenyl group. [5] The release film according to any one of [1] to [4], wherein the polyether-modified silicone contains a hydrosilyl group. [6] The release film according to any one of [1] to [5], wherein the polysiloxane A contains a siloxane unit containing the alkenyl group and a siloxane unit containing the aryl group. [7] The release film according to any one of [1] to [6], wherein when the total number of siloxane units of the polysiloxane A is 100 mol%, the amount of siloxane units containing the aryl group is 0.5 mol% or more or 1 mol% or more. [8] The release film according to any one of [1] to [8], wherein when the total number of siloxane units of the polysiloxane A is 100 mol%, the amount of siloxane units containing the aryl group is 20 mol% or less or 10 mol% or less. [9] The release film according to any one of [1] to [8], wherein the polysiloxane A is a polysiloxane represented by formula A1 described below, and in formula A1, l, m, n, and o are the number of units (i.e., siloxane units), and either m or n may be 0.

[10] The release film according to any one of [1] to [9], wherein the polysiloxane A is a polysiloxane represented by formula A2 described below, and in formula A1, l, m, and o are the number of units (i.e., siloxane units) respectively.

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

[10] , wherein the polyether-modified silicone comprises a siloxane unit containing a hydrosilyl group, and the siloxane unit containing the hydrosilyl group comprises a silicon atom, a hydrogen atom bonded to the silicon atom, and an alkyl group bonded to the silicon atom, wherein the alkyl group is preferably a methyl group.

[12] The polyether-modified silicone contains siloxane units represented by formula PE1, as described later, and R. １ R is an alkyl group. ２ This is the group shown in formula PE2 described later, and R ３ and R ４ Each of these is an alkylene group, and R ５ The release film according to any one of [1] to

[11] , wherein is a hydrogen atom or an alkyl group or a hydroxyl group, and w is 2 or more.

[13] The release film according to any one of [1] to

[12] , wherein the polyether-modified silicone is a silicone represented by formula C1 described below, and in formula C1, x, y, z, and w are the number of their respective units.

[0012] According to the present invention, it is possible to provide a release film that can reduce or suppress the occurrence of repellency.

[0013] Embodiments of the present invention will be described in detail below.

[0014] <1. Release Film> The release film of this embodiment includes a base film and a release layer. Specifically, the release film of this embodiment includes a base film and a release layer provided on at least one surface of the base film.

[0015] <1.1. Release Layer> The release layer is a layer formed by curing the silicone composition. The silicone composition contains polysiloxane A, which contains two or more alkenyl groups in its molecule, and polysiloxane B, which contains two or more hydrosilyl groups in its molecule. Since the silicone composition contains polysiloxane A and polysiloxane B, it can be cured by at least hydrosilylation.

[0016] At least one of polysiloxane A and polysiloxane B in the silicone composition contains an aryl group. Since at least one of polysiloxane A and polysiloxane B contains an aryl group, the water adhesion energy can be improved, and therefore, the occurrence of repulsion when coating a liquid fluid onto a release film can be reduced or suppressed. The improvement in water adhesion energy is thought to be due to the disruption of the arrangement of organic groups (e.g., methyl groups) of the polysiloxane on the surface of the release layer by the aryl group. Since at least one of polysiloxane A and polysiloxane B contains an aryl group, it is also possible to somewhat strengthen the peeling force between the coating film (for example, a coating film formed by coating a liquid fluid onto a release film, drying it, and curing it as needed) and the release film, and therefore, unintended peeling of the coating film can be reduced or prevented. It is preferable that polysiloxane A contains an aryl group. Examples of aryl groups include phenyl, 1-naphthyl, and 2-naphthyl groups. Among these, the phenyl group is preferred.

[0017] <1.1.1. Polysiloxane A> Polysiloxane A contains two or more alkenyl groups in its molecule. Polysiloxane A may contain alkenyl groups in its side chains, at its terminals, or in both its side chains and terminals. As polysiloxane A, polyorganosiloxanes containing alkenyl groups in at least its side chains are preferred, and polyorganosiloxanes containing alkenyl groups only in their side chains are more preferred.

[0018] Examples of alkenyl groups include alkenyl groups having 2 to 10 carbon atoms. Including such alkenyl groups results in excellent strength of the release layer. Preferably, the alkenyl group has 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, and particularly preferably vinyl or hexenyl groups.

[0019] Polysiloxane A may contain siloxane units containing alkenyl groups. With respect to siloxane units containing alkenyl groups, the silicon atom to which the alkenyl group is bonded may have multiple alkenyl groups bonded to it (for example, a second alkenyl group may be bonded to it), or it may have an alkyl group bonded to it. In particular, it is preferable that an alkyl group is bonded to the silicon atom to which the alkenyl group is bonded. In other words, alkylalkenylsiloxane units are preferred as siloxane units containing alkenyl groups.

[0020] A methyl group is preferred as the alkyl group of the alkylalkenylsiloxane unit. That is, a methylalkenylsiloxane unit is preferred as the siloxane unit containing an alkenyl group. Examples of methylalkenylsiloxane units include methylvinylsiloxane units and methylhexenylsiloxane units.

[0021] The number of alkylalkenylsiloxane units may be, for example, 5 or more, 10 or more, or 20 or more. On the other hand, the number of alkylalkenylsiloxane units may be, for example, 200 or less, 150 or less, or 100 or less.

[0022] It is preferable that polysiloxane A further contains dialkylsiloxane units. The two alkyl groups of the dialkylsiloxane unit can each be independently, for example, alkyl groups having 1 to 10 carbon atoms. A methyl group is preferred as the alkyl group of the dialkylsiloxane unit. In other words, a dimethylsiloxane unit is preferred as the dialkylsiloxane unit.

[0023] The number of dialkylsiloxane units may be, for example, 1000 or more, 1500 or more, or 2000 or more. On the other hand, the number of dialkylsiloxane units may be, for example, 10000 or less, 5000 or less, or 4000 or less.

[0024] It is preferable that polysiloxane A further contains alkylphenylsiloxane units. A methyl group is preferred as the alkyl group of the alkylphenylsiloxane unit. In other words, a phenylmethylsiloxane unit is preferred as the alkylphenylsiloxane unit.

[0025] The number of alkylphenylsiloxane units is preferably 10 or more, more preferably 20 or more, and even more preferably 30 or more. It may also be 40 or more, or 50 or more. On the other hand, the number of alkylphenylsiloxane units may be, for example, 500 or less, 300 or less, 200 or less, or 100 or less.

[0026] Furthermore, for the terminal silicon atoms, a trialkylsilane structure such as trimethylsilane is preferred.

[0027] When the total number of siloxane units in polysiloxane A is taken as 100 mol%, the sum of alkylalkenylsiloxane units, dialkylsiloxane units, and alkylphenylsiloxane units is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 98 mol% or more.

[0028] When the total number of siloxane units in polysiloxane A is taken as 100 mol%, the amount of alkylalkenylsiloxane units is preferably 0.6 mol% or more, and more preferably 1 mol% or more, from the viewpoint of release properties and the strength of the release layer. On the other hand, the amount of alkylalkenylsiloxane units is preferably 3 mol% or less, and more preferably 2.4 mol% or less, from the viewpoint of release properties and the strength of the release layer.

[0029] When the number of all siloxane units of polysiloxane A is 100 mol%, the alkylphenylsiloxane unit is preferably 0.5 mol% or more, more preferably 1 mol% or more, and still more preferably 2 mol% or more. When it is 0.5 mol% or more, the water adhesion energy can be further improved. Therefore, when applying a liquid flowing material to the release film, the generation of repellency can be further reduced or suppressed. When it is 0.5 mol% or more, the peeling force between the coating film and the release film (for example, the peeling force when peeling the coating film formed by applying a liquid flowing material to the release film, drying it, and curing it as necessary from the release film) can be further strengthened. Therefore, unintentional peeling of the coating film can be reduced or prevented. On the other hand, the alkylphenylsiloxane unit is preferably 20 mol% or less, more preferably 10 mol% or less, and still more preferably 5 mol% or less. When it is 20 mol% or less, it is possible to prevent the peeling force when peeling the coating film from the release film from becoming excessively strong.

[0030] As the polysiloxane A, the polysiloxane represented by the formula A1 is preferable. In the formula A1, l, m, n, and o are the numbers of their respective units (that is, siloxane units). One of m and n may be 0. That is, the polysiloxane represented by the formula A1 may not contain either the methylvinylsiloxane unit or the methylhexenylsiloxane unit. The description of the sum of m and n is omitted because it overlaps with the description of the number of the above alkylalkenylsiloxane units. Therefore, the description of the number of the alkylalkenylsiloxane units can also be treated as the description of the sum of m and n. The description of l is omitted because it overlaps with the description of the number of the above dialkylsiloxane units. Therefore, the description of the number of the dialkylsiloxane units can also be treated as the description of l. The description of o is omitted because it overlaps with the description of the number of the above alkylphenylsiloxane units. Therefore, the description of the number of the alkylphenylsiloxane units can also be treated as the description of o.

[0031] Formula A1 merely indicates that the numbers of each unit are l, m, n, and o. Therefore, the polysiloxane in Formula A1 may be a random copolymer or a block copolymer.

[0032] As the polysiloxane A, the polysiloxane represented by Formula A2 is more preferable. In Formula A2, the description of l is omitted because it overlaps with the description of the number of dialkylsiloxane units above. Therefore, the description of the number of dialkylsiloxane units can also be regarded as the description of l. The description of m is omitted because it overlaps with the description of the number of alkylalkenylsiloxane units above. Therefore, the description of the number of dialkylsiloxane units can also be regarded as the description of m. The description of o is omitted because it overlaps with the description of the number of alkylphenylsiloxane units above. Therefore, the description of the number of alkylphenylsiloxane units can also be regarded as the description of o.

[0033] Formula A2 merely indicates that the numbers of each unit are l, m, and o. Therefore, the polysiloxane of Formula A2 may be a random copolymer or a block copolymer.

[0034] The weight-average molecular weight of the polysiloxane A is preferably 300,000 or more and 600,000 or less, and more preferably 400,000 or more and 550,000 or less. When it is 300,000 or more, the cured release layer has appropriate strength, and the peeling of the coating film can be reduced. When it is 600,000 or less, the flatness of the coating film after drying is good. The weight-average molecular weight in this specification is a value in terms of standard polystyrene measured by gel permeation chromatography (GPC) method.

[0035] In this embodiment, one type of polysiloxane A may be used alone, or two or more types may be used.

[0036] <1.1.2. Polysiloxane B> Polysiloxane B may contain two or more hydrosilyl groups (groups in which a hydrogen atom is directly bonded to a silicon atom) in its side chains and / or terminals. Hydrogenpolysiloxanes containing hydrosilyl groups in at least the side chains are preferred, and hydrogenpolysiloxanes containing hydrosilyl groups only in the side chains are more preferred.

[0037] Polysiloxane B may contain siloxane units containing hydrosilyl groups. With respect to siloxane units containing hydrosilyl groups, while multiple hydrogen atoms may be directly bonded to the silicon atom to which a hydrogen atom is directly bonded, it is preferable that the hydrogen atom is bonded to an alkyl group. That is, it is preferable that this siloxane unit contains a silicon atom, a hydrogen atom bonded to the silicon atom, and an alkyl group bonded to the silicon atom to which the hydrogen atom is bonded. A methyl group is preferred as the alkyl group.

[0038] The number of siloxane units containing a hydrosilyl group may be, for example, 10 or more, 30 or more, or 40 or more. On the other hand, the number of siloxane units containing a hydrosilyl group may be, for example, 240 or less, 120 or less, or 100 or less.

[0039] It is preferable that polysiloxane B further contains dialkylsiloxane units. The two alkyl groups of the dialkylsiloxane unit can each be independently an alkyl group having, for example, 1 to 10 carbon atoms. A methyl group is preferred as the alkyl group of the dialkylsiloxane unit. In other words, a dimethylsiloxane unit is preferred as the dialkylsiloxane unit.

[0040] The number of dialkylsiloxane units may be, for example, 0.1 or more, 0.2 or more, or 0.3 or more. On the other hand, the number of dialkylsiloxane units may be, for example, 50 or less, 30 or less, or 10 or less.

[0041] Polysiloxane B may further contain other siloxane units. For example, polysiloxane B may further contain alkylphenylsiloxane units.

[0042] Furthermore, for the terminal silicon atoms, a trialkylsilane structure such as trimethylsilane is preferred.

[0043] When the total number of siloxane units in polysiloxane B is taken as 100 mol%, the sum of siloxane units containing hydrosilyl groups and dialkylsiloxane units is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 98 mol% or more.

[0044] When the total number of siloxane units in polysiloxane B is taken as 100 mol%, the amount of siloxane units containing hydrosilyl groups is preferably 30 mol% or more from the viewpoint of the strength of the release layer. The amount of siloxane units containing hydrosilyl groups may be, for example, 70 mol% or more, 80 mol% or more, or 90 mol% or more.

[0045] As polysiloxane B, the polysiloxane represented by formula B1 is preferred. In formula B1, p and q are the number of units (i.e., siloxane units). The explanation for p is omitted as it overlaps with the explanation for the number of dialkylsiloxane units above. Therefore, the explanation for the number of dialkylsiloxane units can also be treated as the explanation for p. The explanation for q is omitted as it overlaps with the explanation for the number of siloxane units containing a hydrosilyl group above. Therefore, the explanation for the number of siloxane units containing a hydrosilyl group can also be treated as the explanation for q.

[0046] Formula B1 merely indicates that the number of units is p and q. Therefore, the polysiloxane in formula B1 may be a random copolymer or a block copolymer.

[0047] The weight-average molecular weight of polysiloxane B is preferably 5000 or more and 100000 or less, more preferably 7000 or more and 20000 or less. When it is 5000 or more, the release layer after curing has appropriate strength, and peeling of the coating film can be reduced. When it is 100000 or less, the flatness of the coating film after drying becomes good.

[0048] In this embodiment, one type of polysiloxane B may be used alone, or two or more types may be used.

[0049] In this embodiment, polysiloxane A and polysiloxane B can preferably be the main components of the release layer by addition polymerization in the presence of a platinum-based catalyst or the like described later. The addition polymerization here means that the functional group in the molecular terminal or molecular side chain of polysiloxane A represented by ~Si-CH=CH ２ or ~Si-R-CH=CH ２ and the functional group in the molecular terminal or molecular side chain of polysiloxane B represented by H-Si~ react to form ~Si-CH ２ CH ２ -Si~ or ~Si-R-CH ２ CH ２ -Si~. Here, "~" in the above functional group indicates that the molecule is further connected. The reaction formula for this reaction is as follows. Here, R represents an alkylene group having 1 to 8 carbon atoms. CAT represents a catalyst.

[0050]

[0051] <1.1.3.Mixing mass ratio and total content of polysiloxane A and B> In the silicone composition, the mixing mass ratio (B / A) of polysiloxane A and polysiloxane B can be set appropriately.

[0052] The total content of polysiloxane A and polysiloxane B is preferably 20% by mass or more, more preferably 40% by mass or more, even more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on 100% by mass of solids in the silicone composition. On the other hand, the total content of polysiloxane A and polysiloxane B is preferably 98% by mass or less, more preferably 97% by mass or less, even more preferably 96% by mass or less, and even more preferably 95% by mass or less. The total content of polysiloxane A and polysiloxane B may be, for example, 94% by mass or less, 92% by mass or less, or 90% by mass or less.

[0053] <1.1.4. Catalyst> The silicone composition preferably contains a catalyst. The catalyst is not particularly limited as long as it can promote the curing reaction of the silicone composition, but a platinum-based catalyst (hereinafter sometimes referred to as "platinum group metal compound") is preferred.

[0054] Examples of platinum group metal compounds include particulate platinum, particulate platinum adsorbed on a carbon powder support, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, palladium, and rhodium. Including such catalysts in a silicone composition allows the curing reaction of the silicone composition to proceed more efficiently.

[0055] The catalyst content in the silicone composition is preferably 1 ppm to 5000 ppm relative to the total mass of polysiloxane A and polysiloxane B.

[0056] <1.1.5. Polyether-Modified Silicone> The silicone composition contains polyether-modified silicone. Because the silicone composition contains polyether-modified silicone, the water adhesion energy can be improved, and therefore, the occurrence of repelling when coating a liquid fluid onto a release film can be reduced or suppressed. The improvement in water adhesion energy is thought to be due to the disruption of the arrangement of polysiloxane organic groups (e.g., methyl groups) on the surface of the release layer by the polyether-modified silicone. The improvement in water adhesion energy is also thought to be due to the hydrophilicity of the polyether groups of the polyether-modified silicone. Because the silicone composition contains polyether-modified silicone, it is also possible to make the peeling force between the coating and the release film somewhat stronger, and therefore, unintended peeling of the coating can be reduced or prevented. If the silicone composition contained polyethylene glycol instead of polyether-modified silicone, the polyethylene glycol would aggregate when the release layer is formed, and repelling, pinholes, and uneven coating may occur starting from the aggregates. In contrast, in the release film of this embodiment, since the silicone composition contains polyether-modified silicone, the formation of aggregates that may occur due to polyethylene glycol can be suppressed or avoided. Therefore, with the release film of this embodiment, it is possible to avoid or reduce repellency, pinholes, and uneven coating that may occur due to the aggregation of polyethylene glycol.

[0057] Polyether-modified silicones may contain siloxane units that include a polyether group. The siloxane unit represented by formula PE1 is preferred as the siloxane unit containing the polyether group. R １ R is an alkyl group. ２ This is a group containing a polyether group.

[0058] R １ Each of these is an alkyl group having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, and a butyl group. Among these, the methyl group is preferred.

[0059] R ２Each of these is an independent group containing a polyether group. Examples of polyether groups include polyethyleneoxy groups and polypropyleneoxy groups. A polyether group may also include a group containing both ethyleneoxy (EO) and propyleneoxy (PO) groups. In this case, the ethyleneoxy (EO) and propyleneoxy (PO) groups may be arranged in a block-like manner or randomly. Each R ２ The polyether group may be linked to Si via a linking group. An example of a linking group is an alkylene group. The number of carbon atoms in the alkylene group may be, for example, 1 to 4. Examples of alkylene groups having 1 to 4 carbon atoms include a methylene group, an ethylene group, a propylene group, and a butylene group. Among these, the propylene group is preferred.

[0060] Note R ２ This can be illustrated, for example, by formula PE2. R ３ and R ４ Each of these is an alkylene group, and R ５ R is a hydrogen atom, alkyl group, or hydroxyl group, and w is 2 or more. ３ The explanation of the alkylene group is omitted as it overlaps with the explanation of the linking group above. Therefore, the explanation of the linking group is R ３ This can also be used as an explanation of the alkylene group. ４ The alkylene groups can each be independent. -O-R ４ Examples of these include ethylene oxy group (EO) and propylene oxy group (PO). ４ The number of carbon atoms is preferably 2 to 8, more preferably 2 to 6, even more preferably 2 to 4, even more preferably 2 to 3, and even more preferably 2. ５ A hydroxyl group is preferred. w is -O-R ４- This is the number of units, i.e., the average number of moles added. w is 2 or more, preferably 5 or more, and more preferably 8 or more. When it is 2 or more, the water adhesion energy can be further improved. w is preferably 50 or less, more preferably 20 or less, even more preferably 16 or less, and even more preferably 13 or less. When it is 50 or less, it is possible to further avoid excessive peeling force when peeling the coating film from the release film.

[0061] The number of siloxane units containing polyether groups is preferably one or more. Having one or more units can further improve the water adhesion energy. The number of siloxane units containing polyether groups may be two or more. On the other hand, the number of siloxane units containing polyether groups is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less. Having 20 or less units can prevent the peeling force when peeling the coating film from the release film from becoming excessively strong.

[0062] The polyether-modified silicone preferably further contains dialkylsiloxane units. The two alkyl groups of the dialkylsiloxane unit can each be independently, for example, alkyl groups having 1 to 10 carbon atoms. A methyl group is preferred as the alkyl group of the dialkylsiloxane unit. In other words, a dimethylsiloxane unit is preferred as the dialkylsiloxane unit.

[0063] The number of dialkylsiloxane units is preferably 10 or more, more preferably 30 or more, even more preferably 40 or more, and even more preferably 50 or more. When the number is 10 or more, it is possible to avoid excessive peeling force when peeling the coating film from the release film. On the other hand, the number of dialkylsiloxane units is preferably 500 or less, more preferably 400 or less, even more preferably 300 or less, even more preferably 200 or less, and even more preferably 100 or less. When the number is 500 or less, the water adhesion energy can be further improved.

[0064] The polyether-modified silicone preferably contains a hydrosilyl group, and more preferably contains a siloxane unit containing a hydrosilyl group. When the polyether-modified silicone contains a hydrosilyl group, it can react with polysiloxane A, and therefore excessive migration of the polyether-modified silicone to the coating film can be suppressed. This siloxane unit preferably contains a silicon atom, a hydrogen atom bonded to the silicon atom, and an alkyl group bonded to the silicon atom to which the hydrogen atom is bonded. A methyl group is preferred as the alkyl group.

[0065] The number of siloxane units containing hydrosilyl groups is preferably 0.01 or more, and more preferably 0.05 or more. When it is 0.01 or more, the polyether-modified silicone can react effectively with polysiloxane A, and therefore, excessive migration of the polyether-modified silicone to the coating film can be further suppressed. The number of siloxane units containing hydrosilyl groups may be 0.10 or more. On the other hand, the number of siloxane units containing hydrosilyl groups may be, for example, 20 or less, 10 or less, or 5 or less.

[0066] As the polyether-modified silicone, the silicone represented by formula C1 is preferred. In formula C1, x, y, z, and w are the number of units. The explanation for x is omitted as it overlaps with the explanation for the number of siloxane units containing hydrosilyl groups described above. Therefore, the explanation for the number of siloxane units containing hydrosilyl groups can also be treated as the explanation for x. The explanation for y is omitted as it overlaps with the explanation for the number of siloxane units containing polyether groups described above. Therefore, the explanation for the number of siloxane units containing polyether groups can also be treated as the explanation for y. The explanation for z is omitted as it overlaps with the explanation for the number of dialkylsiloxane units described above. Therefore, the explanation for the number of dialkylsiloxane units can also be treated as the explanation for z. w is as described above.

[0067] Equation C1 merely indicates that the number of units for x, y, and z are x, y, and z, respectively. Therefore, the silicone in equation C1 may be a random copolymer or a block copolymer.

[0068] The polyether content in the polyether-modified silicone is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and still more preferably 20 parts by mass or more, when the total amount of all components constituting the polyether-modified silicone is 100 parts by mass. When it is 5 parts by mass or more, the water adhesion energy can be further improved. On the other hand, the polyether content in the polyether-modified silicone is preferably 80 parts by mass or less, more preferably 60 parts by mass or less, even more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, and still more preferably 30 parts by mass or less, when the total amount of all components constituting the polyether-modified silicone is 100 parts by mass. When it is 80 parts by mass or less, it is possible to avoid the peeling force when peeling the coating film from the release film (for example, the peeling force when peeling a coating film formed by coating a liquid fluid such as a ceramic slurry onto a release film, drying it, and curing it as necessary, from the release film) becoming excessively strong. Here, when the polyether-modified silicone contains the siloxane unit shown in formula PE1, the R of formula PE1 ２ This is the polyether component. The polyether content in polyether-modified silicone can be measured by nuclear magnetic resonance (NMR), chromatography, etc.

[0069] The weight-average molecular weight of the polyether-modified silicone is preferably 1,000 to 100,000, and more preferably 3,000 to 50,000. If it is 1,000 or more, the migration of the polyether-modified silicone to the coating film can be reduced or suppressed. On the other hand, if it is 100,000 or less, the polyether-modified silicone is more likely to segregate on the surface of the release layer, further improving the water adhesion energy.

[0070] In this embodiment, one type of polyether-modified silicone may be used alone, or two or more types may be used.

[0071] The polyether-modified silicone content is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, even more preferably 8% by mass or more, and even more preferably 10% by mass or more, based on 100% by mass of solids in the silicone composition. A content of 1% by mass or more can further improve water adhesion energy. On the other hand, the polyether-modified silicone content is preferably 45% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less, even more preferably 25% by mass or less, even more preferably 20% by mass or less, and even more preferably 15% by mass or less. A content of 45% by mass or less can avoid excessive peeling force when peeling the coating from the release film.

[0072] The polyether-modified silicone content in the release layer is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, even more preferably 8% by mass or more, and even more preferably 10% by mass or more. On the other hand, the polyether-modified silicone content in the release layer is preferably 45% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less, even more preferably 25% by mass or less, even more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0073] <1.1.6. Other Components> In addition to the above components, the silicone composition may also contain reaction inhibitors, solvents, silicone resins that do not have reactive functional groups, antistatic agents, melamine resins, silane coupling agents, etc.

[0074] <1.1.7. Thickness of the release layer> The thickness of the release layer is preferably 0.005 μm or more, more preferably 0.01 μm or more, and even more preferably 0.02 μm or more. When it is 0.005 μm or more, it can effectively perform its function as a release layer and can suppress the exposure of a part of the base film due to unevenness in the thickness of the release layer. On the other hand, the thickness of the release layer is preferably 0.5 μm or less, more preferably 0.1 μm or less, and even more preferably 0.05 μm or less. When it is 0.5 μm or less, it can suppress the occurrence of fracture within the release layer, i.e., cohesive fracture.

[0075] <1.2. Base Film> Examples of base films include polyester film and polyolefin film. Polyester film is preferred because it has high heat resistance and can therefore be dried and cured at high temperatures after coating with fluid material. The base film may also be surface treated. Examples of surface treatments include corona treatment and plasma treatment. The base film may also contain an easy-adhesion layer, an antistatic layer, a smoothing layer, etc.

[0076] A polyester film is a film containing polyester as a resin component, and preferably a film in which polyester is the most abundant component in the resin (for example, 90% by mass or more).

[0077] The polyester constituting the polyester film is not particularly limited, and a film made from polyester commonly used as a base material for release films can be used. Preferably, it is a crystalline linear saturated polyester consisting of an aromatic dibasic acid component and a diol component, and more preferably, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polytrimethylene terephthalate, or copolymers mainly composed of these resin components.

[0078] In particular, polyester films formed from polyethylene terephthalate are especially preferred. The polyethylene terephthalate preferably has a repeating unit content of ethylene terephthalate of 90 mol% or more, more preferably 95 mol% or more, and may also have small amounts of other dicarboxylic acid components and diol components copolymerized. For example, from a cost standpoint, those produced solely from terephthalic acid and ethylene glycol are preferred. The polyester film may also contain known additives, such as antioxidants, light stabilizers, ultraviolet absorbers, and crystallizers. The polyester film is preferably a biaxially oriented polyester film due to reasons such as its high bidirectional modulus of elasticity.

[0079] The intrinsic viscosity of the polyethylene terephthalate film is preferably 0.50 dl / g or more and 0.70 dl / g or less, and more preferably 0.52 dl / g or more and 0.62 dl / g or less. If the intrinsic viscosity is 0.50 dl / g or more, the frequency of breakage during the stretching process can be reduced. On the other hand, if the viscosity is 0.70 dl / g or less, the cutability when cutting to a predetermined product width is good, and therefore the frequency of dimensional defects can be reduced. Incidentally, it is preferable to thoroughly vacuum dry the raw material pellets.

[0080] In this specification, when the term "polyester film" is used, it may mean a polyester film that includes (is laminated with) surface layer A and surface layer B.

[0081] The method for manufacturing polyester film is not particularly limited, and conventional methods can be used. For example, the polyester can be melted in an extruder, extruded into a film, and cooled in a rotating cooling drum to obtain an unstretched film, which can then be obtained by uniaxial or biaxial stretching. Biaxially oriented film can be obtained by sequentially biaxially stretching a uniaxially oriented film in the longitudinal or transverse direction in the transverse or longitudinal direction, or by simultaneously biaxially stretching an unstretched film in the longitudinal and transverse directions.

[0082] It is preferable that the stretching temperature during polyester film stretching be above the secondary transition temperature (Tg) of polyester. It is also preferable to stretch the film by 1 to 8 times, and particularly 2 to 6 times, in both the longitudinal and transverse directions.

[0083] The polyester film is preferably 12 μm or more and 100 μm or less in thickness, more preferably 15 μm or more and 50 μm or less, and more preferably 19 μm or more and 38 μm or less. A film thickness of 12 μm or more is preferable because there is no risk of deformation due to heat during film production, processing, or molding. On the other hand, a film thickness of 100 μm or less is preferable because the amount of film to be discarded after use is not excessively large, thus reducing the environmental burden.

[0084] The polyester film may be a single layer or a multilayer of two or more layers. For example, the polyester film may include a surface layer A that substantially does not contain particles with a particle size of 1.0 μm or larger, and a surface layer B that contains particles. It is preferable that surface layer A substantially does not contain inorganic particles with a particle size of 1.0 μm or larger.

[0085] In this embodiment, the surface layer A may contain particles with a particle size of less than 1.0 μm and 1 nm or larger. By substantially excluding particles with a particle size of 1.0 μm or larger, such as inorganic particles, from the surface layer A, it is possible to reduce the transfer of the particle shape in the substrate to the resin sheet, which can cause defects.

[0086] In one embodiment, by not including any particles with a particle size of less than 1.0 μm in the surface layer A, it is possible to more effectively suppress defects caused by the transfer of the particle shape in the substrate to the resin sheet.

[0087] In one embodiment, the polyester film substrate is preferably a laminated film having a surface layer A on at least one side that is substantially free of inorganic particles. This further effectively suppresses the transfer of particle shapes from the substrate to the resin sheet, which can cause defects.

[0088] For example, a surface layer A that substantially does not contain particles with a particle size of less than 1.0 μm is preferably a surface layer A that also substantially does not contain particles with a particle size of 1.0 μm or larger.

[0089] In this invention, "substantially free of particles" means, for example, in the case of inorganic particles smaller than 1.0 μm, that the content of inorganic elements when quantified by fluorescence X-ray analysis is 50 ppm or less, preferably 10 ppm or less, and most preferably below the detection limit. This is because even without actively adding particles to the film, contaminants originating from foreign substances, or dirt adhering to the raw material resin or the lines and equipment in the film manufacturing process, may peel off and become mixed into the film. Furthermore, "substantially free of particles with a particle size of 1.0 μm or larger" means that the film does not actively contain particles with a particle size of 1.0 μm or larger.

[0090] In the case of a laminated polyester film consisting of two or more layers, it is preferable that the surface opposite to surface layer A, which substantially does not contain inorganic particles, has a surface layer B that may contain inorganic particles.

[0091] In terms of the lamination structure, if the layer on the side to which the release layer is applied is designated as layer A, the layer on the opposite side as layer B, and the remaining core layer as layer C, then the layer configuration in the thickness direction can be a laminated structure such as release layer / A / B or release layer / A / C / B. Naturally, layer C may consist of multiple layers. Furthermore, the surface layer B may not contain inorganic particles. In that case, it is preferable to provide a coating layer D containing at least inorganic particles and a binder on the surface layer B in order to provide slipperiness for winding the film into a roll.

[0092] In the polyester film substrate of the present invention, the surface layer B that forms the opposite side of the surface to which the release layer is applied preferably contains inorganic particles from the viewpoint of the film's slipperiness and ease of air release, and it is particularly preferable to use silica particles and / or calcium carbonate particles. The inorganic particle content is preferably 5,000 ppm to 15,000 ppm in total in the surface layer B.

[0093] In this case, the average surface roughness (Sa) of the surface layer B of the film is preferably in the range of 1 nm to 40 nm. More preferably, it is in the range of 5 nm to 35 nm. When the total amount of silica particles and / or calcium carbonate particles is 5000 ppm or more and Sa is 1 nm or more, when the film is wound into a roll, air can be released uniformly, resulting in a good winding shape and good flatness, making it suitable for the manufacture of resin sheets and the like. Furthermore, when the total amount of silica particles and / or calcium carbonate particles is 15000 ppm or less and Sa is 40 nm or less, lubricant aggregation is less likely to occur, and no coarse protrusions are formed, resulting in stable quality during the manufacture of resin sheets and the like, which is preferable.

[0094] In addition to silica and / or calcium carbonate, other inert inorganic particles and / or heat-resistant organic particles can be used as particles in the above-mentioned B layer, but silica particles and / or calcium carbonate particles are more preferable from the viewpoint of transparency and cost. Other inorganic particles that can be used include alumina-silica composite oxide particles and hydroxyapatite particles. Heat-resistant organic particles include cross-linked polyacrylic particles, cross-linked polystyrene particles and benzoguanamine particles. When silica particles are used, porous colloidal silica is preferred, and when calcium carbonate particles are used, light calcium carbonate surface-treated with a polyacrylic acid-based polymer compound is preferred from the viewpoint of preventing lubricant detachment.

[0095] The average particle diameter of the inorganic particles added to the surface layer B is preferably 0.1 μm or more and 2.0 μm or less, and particularly preferably 0.5 μm or more and 1.0 μm or less. If the average particle diameter of the inorganic particles is 0.1 μm or more, the slipperiness of the release film is good, which is preferable. Furthermore, if the average particle diameter is 2.0 μm or less, there is no risk of adversely affecting the smoothness of the surface of the release layer, and therefore there is no risk of pinholes occurring in the resin sheet, which is preferable. The average particle diameter of the particles can be measured by observing the particles in the cross-section of the processed film with a scanning electron microscope, observing 100 particles, and taking the average value. The shape of the particles is not particularly limited as long as it satisfies the purpose of the present invention, and spherical particles or irregularly shaped non-spherical particles can be used. The particle diameter of irregularly shaped particles can be calculated as the equivalent diameter of a circle. The equivalent diameter of a circle is the value obtained by dividing the area of ​​the observed particle by pi (π), calculating the square root, and multiplying by 2.

[0096] In the surface layer A, which is the layer on the side where the release layer is provided, it is preferable not to use recycled materials or the like in order to prevent the inclusion of inorganic particles such as lubricants, from the viewpoint of reducing pinholes.

[0097] The thickness ratio of surface layer A, which is the layer on which the release layer is provided, is preferably 20% to 50% of the total thickness of the base film. If it is 20% or more, the film is less affected by particles contained in surface layer B and the like from inside, and it is easier for the average surface roughness Sa to satisfy the above range, which is preferable. If it is 50% or less of the total thickness of the base film, the proportion of recycled materials used in surface layer B can be increased, which is preferable as it reduces the environmental impact.

[0098] Furthermore, from an economic standpoint, 50% to 90% by mass of recycled film scraps or PET bottles can be used in layers other than the surface layer A (surface layer B or the aforementioned intermediate layer C). In this case as well, it is preferable that the type, amount, particle size, and average surface roughness (Sa) of the lubricant contained in layer B satisfy the above range.

[0099] Furthermore, a coating layer D may be provided on the surface of surface layer A and / or surface layer B before stretching or after uniaxial stretching during the film-forming process to improve the adhesion of a release layer or other coating applied later, or to prevent static charge buildup. Corona treatment may also be applied.

[0100] If the surface layer B does not contain particles, it is also preferable to provide slipperiness by applying a coating layer D containing particles on the surface layer B. The means of providing this coating layer D are not particularly limited, but it is preferable to provide it by a so-called in-line coating method, which involves coating it during the formation of the polyester film. Furthermore, when providing a coating layer D that provides slipperiness to the surface of the polyester film that does not have a release layer laminated on it, the polyester film does not need to contain surface layers A and B, and may consist of a single layer of polyester film that substantially does not contain inorganic particles.

[0101] The average surface roughness (Sa) of surface layer B is preferably 40 nm or less, more preferably 35 nm or less, and even more preferably 30 nm or less. Furthermore, if a coating layer D is applied to the surface of surface layer B or the side of the single-layer polyester film that does not have a release layer laminated, the Sa of that surface should be measured on the surface to which the coating layer D is laminated, and it is preferable that it be within the same range as the average surface roughness (Sa) of surface layer B.

[0102] <1.3. Formation of the release layer> In the present invention, the method for forming the release layer is not particularly limited. A coating solution containing a dissolved or dispersed release compound is applied to one side of the polyester film substrate, and after removing the solvent by drying, the solution is cured. A method of curing by heat simultaneously with solvent removal may also be used.

[0103] When the release layer of the present invention is applied to a substrate film by solution coating, the drying temperature for solvent drying is preferably 50°C to 200°C, and more preferably 100°C to 180°C. The drying time is preferably 30 seconds or less, and more preferably 20 seconds or less.

[0104] The surface tension of the coating liquid when applying the release layer is not particularly limited, but is preferably 30 mN / m or less. By setting the surface tension as described above, the wettability after coating is improved, and the surface irregularities of the coating film after drying can be reduced.

[0105] Any known coating method can be applied to the above coating liquid. For example, conventional methods such as roll coating methods including gravure coating and reverse coating, bar coating methods such as wire bar coating, die coating, spray coating, and air knife coating can be used.

[0106] <2. Physical properties of the release film> The water adhesion energy on the surface of the release layer, that is, the adhesion energy determined by measuring the sliding angle using water, is 9.5 mJ / m ２ The above is preferable, and 10.0 mJ / m ２ The above is more preferable. The water adhesion energy on the release layer surface is measured by the method described in the examples below.

[0107] After bonding the release film to the adhesive tape, the peeling force measured by the T-type peeling method at room temperature (specifically 22°C) with a peeling speed of 300 mm / min. is preferably 200 mN / 50 mm or less, and more preferably 180 mN / 50 mm or less. On the other hand, the peeling force is preferably 10 mN / 50 mm or more, more preferably 50 mN / 50 mm or more, and even more preferably 90 mN / 50 mm or more. This peeling force is measured by the method described in the examples below.

[0108] These physical properties (specifically, water adhesion energy and release force) can be appropriately set depending on the application of the release film. Of course, these physical property values ​​may fall outside the preferred numerical ranges mentioned above.

[0109] <3. Applications of the Release Film> The applications of the release film of this embodiment are not particularly limited. For example, it can be used in the manufacture of adhesive sheets, cover films, ceramic green sheets, polymer films, resin sheets, optical lenses, and multilayer printed circuit boards. In the manufacture of ceramic green sheets, for example, the release film of this embodiment can be used to manufacture ceramic green sheets for multilayer ceramic capacitors. In the manufacture of multilayer printed circuit boards, for example, the release film of this embodiment can be used as a support film to support the insulating layer when manufacturing multilayer printed circuit boards using the build-up method. Because the release film of this embodiment has excellent slurry coating and peelability, it can be used as a release film for molding various resin sheets and the like.

[0110] The present invention will be explained in more detail with the following examples. Hereafter, unless otherwise specified, "parts" means "parts by mass" and "%" means "percent mass".

[0111] <Measurement Method for Each Physical Property> (Weight-Average Molecular Weight) A sample solution adjusted to a sample concentration of 0.2% was filtered through a 0.2 μm membrane filter, and gel permeation chromatography (GPC) analysis was performed under the following conditions to determine the weight-average molecular weight. Molecular weight was calculated on a standard polystyrene basis. Apparatus: TOSOH HLC-8320GPC Column: TSKgel SuperHM-H x 2 + TSKgel SuperH2000 (TOSOH) Solvent: 100% chloroform Flow rate: 0.6 mL / min Concentration: 0.2% Injection volume: 20 μL Temperature: 40°C Detector: RI

[0112] (Release Layer Thickness) The release film was embedded in resin and ultrathin sectioned using an ultramicrotome. Then, cross-sectional observation was performed using a JEM2100 transmission electron microscope manufactured by JEOL Ltd., and the thickness of the release layer was measured from the observed TEM images. If the thickness was too thin to be accurately evaluated by cross-sectional observation, the Si intensity was measured using an X-ray fluorescence spectrometer (ZSX PRIMUS II manufactured by Rigaku Corporation), and the coating amount was calculated using the calibration curve method.

[0113] (Release strength of the release layer tape) Adhesive tape ("31B" manufactured by Nitto Denko Corporation) was attached to the surface of the release film, and after being pressed with a pressure roller with a linear pressure of 5 kgf / mm, it was left for 20 hours under conditions of 22°C and 60% humidity. The release film with the adhesive tape attached was cut into strips with a width of 25 mm and a length of 150 mm. With one end of the adhesive tape fixed and one end of the release film supported, the release film was pulled at a speed of 300 mm / min. and the peel strength (i.e., T-shaped peel strength) was measured. A tensile testing machine ("AUTOGRAPHAG-A-1" manufactured by Shimadzu Corporation) was used for the measurement. The results are shown in Table 1.

[0114] (Water adhesion energy of the release layer) The water adhesion energy of the release film was measured using a fully automatic contact angle meter DM-701 manufactured by Kyowa Interface Science Co., Ltd. Specifically, in an environment with a temperature of 23 degrees Celsius and a humidity of 50%, the release film was placed on a flat glass substrate and fixed in place. With the glass substrate tilted at 0 degrees (i.e., horizontal), a 20.0 μL droplet of water was dropped onto the surface of the release layer of the release film. Three seconds after the droplet came to rest, the glass substrate was tilted at a speed of 2 degrees / second. The adhesion energy (mJ / m) was calculated from the droplet's sliding angle, landing radius, droplet mass, and gravitational acceleration when the endpoint of the droplet left the resting position, using the following formula. ２The following formula was used to calculate the adhesion energy: E = (m × g × sinα) / (2 × π × r) In this formula, E is the adhesion energy, m is the droplet mass, g is the acceleration due to gravity, α is the sliding angle, and r is the landing radius. The distance at which the endpoint of the water droplet was judged to have moved away from the stationary position, i.e., the distance at which movement was judged to have occurred, was 50 dots. The adhesion energy was measured three times. The average value of the three measurement results is shown in Table 1. Note that the maximum tilt angle of the glass substrate is 90°, and for release films in which the droplet did not slide off at 90° (i.e., the droplet movement was less than 50 dots), the adhesion energy was calculated with α = 90°. Table 1 shows that for release films in which the droplet did not slide off at 90°, the adhesion energy was greater than or equal to the calculated value.

[0115] <Example 1> The preparation of the release film in Example 1 will be described later.

[0116] <Example 2> A thermo-additive silicone resin TS2, a polyether-modified silicone PS1 (a polyether-modified silicone with w=11, x=0.4, y=3, z=60 in formula C1; weight-average molecular weight 6000), methyl ethyl ketone, toluene, and catalyst C2 (manufactured by Shin-Etsu Chemical Co., Ltd., CAT-PL-3 (platinum complex solid content concentration 5%)) were prepared. Here, the thermo-additive silicone resin TS2 was prepared by adjusting the molar ratio (amount of hydrosilyl group / amount of alkenyl group) of a polysiloxane (weight-average molecular weight 570000) with l=2700, m=30, o=60 in formula A2 and a polysiloxane (i.e., polymethylhydrogensiloxane) (weight-average molecular weight 8400) with p=0.5, q=60 in formula B1 to 3.5. These were mixed according to the following formulation to obtain coating solution M2. (Coating liquid M2) Methyl ethyl ketone 49.16 parts by mass Toluene 49.16 parts by mass Heat-added silicone resin TS2 (solid content concentration 30%) 1.50 parts by mass Polyether-modified silicone PS1 (solid content concentration 100%) 0.06 parts by mass Catalyst C2 (solid content concentration 5%) 0.03 parts by mass Coating liquid M2 was coated onto one side (specifically the corona-treated side) of a polyester film (Toyobo Ester Film E5100 manufactured by Toyobo Co., Ltd., thickness 38 μm, one side corona-treated) using reverse gravure so that the release layer thickness was as shown in Table 1. Then, the processing speed was adjusted so that it entered the first drying oven after 0.5 seconds, and heating and drying and curing of the release layer were carried out continuously at the first drying oven temperature of 120°C and the second drying oven temperature of 160°C to obtain a release film.

[0117] <Example 3> A thermal addition silicone resin TS1 (Dowsil LTC310, manufactured by Dow Toray Industries, Ltd., solids content 30%, molar ratio (specifically, hydrosilyl group amount / alkenyl group amount) = 1.2), polyether-modified silicone PS1, methyl ethyl ketone, toluene, and catalyst C1 (SRX212, manufactured by Dow Toray Industries, Ltd. (platinum complex of 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, solids content 5%)) were prepared. These were mixed according to the following formulation to obtain coating solution M3. (Coating liquid M3) 49.07 parts by mass of methyl ethyl ketone, 49.07 parts by mass of toluene, 1.50 parts by mass of heat-added silicone resin TS1 (solid content concentration 30%), 0.06 parts by mass of polyether-modified silicone PS1 (solid content concentration 100%), 0.03 parts by mass of catalyst C1 (solid content concentration 5%). Coating liquid M3 was applied to one side (specifically the corona-treated side) of a polyester film (Toyobo Ester Film E5100 manufactured by Toyobo Co., Ltd., thickness 38 μm, one side corona-treated) using reverse gravure so that the release layer thickness was as shown in Table 1. Then, the processing speed was adjusted so that it entered the first drying oven after 0.5 seconds, and continuous heating and drying and curing of the release layer were performed at a first drying oven temperature of 100°C and a second drying oven temperature of 130°C to obtain a release film.

[0118] <Example 4> A release film was prepared in the same manner as in Example 2, except that a coating solution M4 with the following composition was prepared instead of coating solution M2. (Coating solution M4) Methyl ethyl ketone 48.33 parts by mass Toluene 48.33 parts by mass Thermal addition type silicone resin TS2 (solid content concentration 30%) 3.00 parts by mass Polyether modified silicone PS1 (solid content concentration 100%) 0.11 parts by mass Catalyst C2 (solid content concentration 5%) 0.03 parts by mass

[0119] <Example 5> A release film was prepared in the same manner as in Example 3, except that a coating solution M5 with the following composition was prepared instead of coating solution M3. (Coating solution M5) Methyl ethyl ketone 49.23 parts by mass Toluene 49.23 parts by mass Thermal addition type silicone resin TS2 (solid content concentration 30%) 1.30 parts by mass Polyether modified silicone PS1 (solid content concentration 100%) 0.11 parts by mass Catalyst C1 (solid content concentration 5%) 0.03 parts by mass

[0120] <Example 6> A release film was prepared in the same manner as in Example 3, except that a coating solution M6 with the following composition was prepared instead of coating solution M3. (Coating solution M6) Methyl ethyl ketone 49.04 parts by mass Toluene 49.04 parts by mass Thermal addition type silicone resin TS1 (solids concentration 30%) 1.57 parts by mass Polyether modified silicone PS2 (solids concentration 100%) 0.03 parts by mass Catalyst C1 (solids concentration 5%) 0.03 parts by mass Here, the polyether modified silicone PS2 is TSF4446 (solids concentration 100%) manufactured by Momentive Performance Materials Japan LLC.

[0121] <Example 7> A release film was prepared in the same manner as in Example 3, except that a coating solution M7 with the following composition was prepared instead of coating solution M3. (Coating solution M7) Methyl ethyl ketone 49.04 parts by mass Toluene 49.04 parts by mass Thermal addition type silicone resin TS1 (solid content concentration 30%) 1.58 parts by mass Polyether modified silicone PS3 (solid content concentration 100%) 0.03 parts by mass Catalyst C1 (solid content concentration 5%) 0.03 parts by mass Here, the polyether modified silicone PS3 is KF-6015 (solid content concentration 100%) manufactured by Shin-Etsu Chemical Co., Ltd.

[0122] <Example 8> A release film was prepared in the same manner as in Example 3, except that a coating solution M8 with the following composition was prepared instead of coating solution M3. (Coating solution M8) Methyl ethyl ketone 49.04 parts by mass Toluene 49.04 parts by mass Thermal addition type silicone resin TS1 (solid content concentration 30%) 1.58 parts by mass Polyether modified silicone PS4 (solid content concentration 100%) 0.03 parts by mass Catalyst C1 (solid content concentration 5%) 0.03 parts by mass Here, the polyether modified silicone PS4 is KF-6017 (solid content concentration 100%) manufactured by Shin-Etsu Chemical Co., Ltd.

[0123] <Example 9> A release film was prepared in the same manner as in Example 3, except that a coating solution M9 with the following composition was prepared instead of coating solution M3. (Coating solution M9) Methyl ethyl ketone 49.04 parts by mass Toluene 49.04 parts by mass Thermal addition type silicone resin TS1 (solid content concentration 30%) 1.58 parts by mass Polyether modified silicone PS5 (solid content concentration 100%) 0.03 parts by mass Catalyst C1 (solid content concentration 5%) 0.03 parts by mass Here, the polyether modified silicone PS5 is KF-6004 (solid content concentration 100%) manufactured by Shin-Etsu Chemical Co., Ltd.

[0124] <Example 10> A release film was prepared in the same manner as in Example 3, except that a coating solution M10 with the following composition was prepared instead of coating solution M3. (Coating solution M10) Methyl ethyl ketone 49.04 parts by mass Toluene 49.04 parts by mass Thermal addition type silicone resin TS1 (solid content concentration 30%) 1.58 parts by mass Polyether modified silicone PS6 (solid content concentration 100%) 0.03 parts by mass Catalyst C1 (solid content concentration 5%) 0.03 parts by mass Here, the polyether modified silicone PS6 is KF-6028 (solid content concentration 100%) manufactured by Shin-Etsu Chemical Co., Ltd.

[0125] <Example 11> A release film was prepared in the same manner as in Example 3, except that a coating solution M11 with the following composition was prepared instead of coating solution M3. (Coating solution M11) Methyl ethyl ketone 49.04 parts by mass Toluene 49.04 parts by mass Thermal addition type silicone resin TS1 (solid content concentration 30%) 1.58 parts by mass Polyether modified silicone PS7 (solid content concentration 100%) 0.03 parts by mass Catalyst C1 (solid content concentration 5%) 0.03 parts by mass Here, the polyether modified silicone PS7 is KF-6038 (solid content concentration 100%) manufactured by Shin-Etsu Chemical Co., Ltd.

[0126] <Example 12> A release film was prepared in the same manner as in Example 3, except that a coating solution M12 with the following composition was prepared instead of coating solution M3. (Coating solution M12) Methyl ethyl ketone 49.04 parts by mass Toluene 49.04 parts by mass Thermal addition type silicone resin TS2 (solids concentration 30%) 1.57 parts by mass Polyether modified silicone PS8 (solids concentration 100%) 0.03 parts by mass Catalyst C1 (solids concentration 5%) 0.03 parts by mass Here, the polyether modified silicone PS8 is TSF4452 (solids concentration 100%) manufactured by Momentive Performance Materials Japan LLC.

[0127] <Example 13> A release film was prepared in the same manner as in Example 3, except that a coating solution M13 with the following composition was prepared instead of coating solution M3. (Coating solution M13) Methyl ethyl ketone 49.02 parts by mass Toluene 49.02 parts by mass Thermal addition type silicone resin TS2 (solid content concentration 30%) 1.63 parts by mass Polyether modified silicone PS1 (solid content concentration 100%) 0.01 parts by mass Catalyst C1 (solid content concentration 5%) 0.03 parts by mass

[0128] <Example 14> A release film was prepared in the same manner as in Example 3, except that a coating solution M14 with the following composition was prepared instead of coating solution M3. (Coating solution M14) Methyl ethyl ketone 49.24 parts by mass Toluene 49.24 parts by mass Heat-added silicone resin TS2 (solid content concentration 30%) 0.98 parts by mass Polyether-modified silicone PS1 (solid content concentration 100%) 0.21 parts by mass Catalyst C1 (solid content concentration 5%) 0.03 parts by mass

[0129] <Example 15> A release film was prepared in the same manner as in Example 3, except that a coating solution M15 with the following composition was prepared instead of coating solution M3. (Coating solution M15) Methyl ethyl ketone 49.00 parts by mass Toluene 49.00 parts by mass Thermal addition type silicone resin TS1 (solid content concentration 30%) 1.67 parts by mass Catalyst C1 (solid content concentration 5%) 0.03 parts by mass

[0130] <Example 16> A release film was prepared in the same manner as in Example 2, except that a coating solution M16 with the following composition was prepared instead of coating solution M2. (Coating solution M16) Methyl ethyl ketone 49.16 parts by mass Toluene 49.16 parts by mass Thermal addition type silicone resin TS2 (solid content concentration 30%) 1.67 parts by mass Catalyst C2 (solid content concentration 5%) 0.03 parts by mass

[0131] <Example 1> A release film was prepared in the same manner as in Example 2, except that a coating solution M1 with the following composition was prepared instead of coating solution M2. (Coating solution M1) Methyl ethyl ketone 49.03 parts by mass Toluene 49.03 parts by mass Thermal addition type silicone resin TS2 (solid content concentration 30%) 1.60 parts by mass Polyethylene glycol 0.02 parts by mass Catalyst C2 (solid content concentration 5%) 0.03 parts by mass Here, polyethylene glycol is polyethylene glycol 400 (hereinafter sometimes referred to as "PEG400") with a weight-average molecular weight of 7000.

[0132] <Results> The table containing the results is shown below. In this table, "PS content" refers to the content of polyether-modified silicone solids in the total 100% by mass of the solids of the heat-added silicone resin and the polyether-modified silicone. In other words, the PS content is the content of polyether-modified silicone in the release layer. Examples 2, 4, 5, 12, 13, and 14 correspond to embodiments that embody the above [1] (i.e., item 1).

[0133] Polyether-modified silicones improved water adhesion energy and increased release force (see, for example, Examples 2, 4, 5, 12, 13, 14, and 16). The water adhesion energy of release films made with phenyl-containing thermal addition silicone resin TS2 was higher than that of release films made with phenyl-free thermal addition silicone resin TS1 (see, for example, Examples 2 and 3; Examples 15 and 16). The release force of the former was stronger than that of the latter.

[0134] The appearance of the release film manufactured with added polyethylene glycol (specifically, the release film in Example 1) was worse than that of the other release films (specifically, the release films in Examples 2 to 16). This is thought to be because the polyethylene glycol aggregated during the formation of the release layer.

[0135] Since this invention can provide a release film, it has potential for industrial applications.

Claims

1. A release film comprising a base film and a release layer, wherein the release layer is a cured layer of a silicone composition, and the silicone composition comprises a polysiloxane A containing two or more alkenyl groups in its molecule, a polysiloxane B containing two or more hydrosilyl groups in its molecule, and a polyether-modified silicone, wherein at least one of the polysiloxane A and the polysiloxane B contains an aryl group.

2. The release film according to claim 1, wherein the content of the polyether-modified silicone in the release layer is 3% by mass or more and 35% by mass or less.

3. The release film according to claim 1, wherein the polysiloxane A contains the aryl group.

4. The release film according to claim 1, wherein the aryl group is a phenyl group.

5. The release film according to claim 1, wherein the polyether-modified silicone contains a hydrosilyl group.

Images