JP2012149240A - Primer composition for silicone adhesive, laminate, and silicone adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a primer composition capable of firmly adhering a silicone adhesive to a sheet base material; and to provide a laminate and a silicone adhesive tape, obtained by firmly adhering a silicone adhesive and a sheet base material.SOLUTION: The primer composition for a silicone adhesive includes (A) a diorganopolysiloxane of an average structural formula (1): RRSiO(RSiO)SiRR, wherein Ris a 2-10C alkenyl group; Ris a 1-10C monovalent hydrocarbon group or halogenated hydrocarbon group having no aliphatic unsaturated bond; and P+2 is 400 to 2,000 in average, (B) an organohydrogenpolysiloxane of an average composition formula (2): (RSiO)(RHSiO)(RSiO)n(RSiO), wherein Ris the same as R; and k is the number of (2+p) in average, m is 100 to 500 in average, n and p are ≥0 in average, m, n and p satisfies 100≤m+n+p≤500 and 0.8≤m/(m+n+p)≤1, and (C) a hydrosilylation reaction catalyst. There are also provided: a sheet base material; and a laminate having a primer layer obtained by curing the primer composition on a sheet base material and a silicone adhesive layer on the primer layer; and a silicone adhesive tape having the above structure.

Description

The present invention relates to a primer composition for a silicone pressure-sensitive adhesive, a laminate, and a silicone pressure-sensitive adhesive tape. More specifically, the primer composition for firmly bonding a silicone pressure-sensitive adhesive to a sheet-like substrate such as a plastic film, on the sheet-like substrate. A laminate comprising a silicone adhesive layer provided via a cured product layer of the primer composition, and a silicone provided with a silicone adhesive layer provided via a cured product layer of the primer composition on a plastic film tape. It relates to an adhesive tape.

Silicone pressure-sensitive adhesive compositions, i.e., silicone pressure-sensitive adhesive compositions, are electrically insulative compared to organic pressure-sensitive adhesive compositions such as acrylic and organic rubber-based, i.e., organic pressure-sensitive adhesive compositions. , Heat resistance, cold resistance, adhesiveness to various adherends, that is, excellent in pressure-sensitive adhesiveness, it is used in applications such as heat-resistant tape, electrical insulating tape, heat seal tape, plating masking tape, etc. ing. These pressure-sensitive adhesive tapes are usually wound up in a roll shape. However, when strongly rewound at the time of use, the silicone pressure-sensitive adhesive layer may be peeled off from a sheet-like substrate such as a plastic film. Further, when the adhesive tape is cut, only the plastic film substrate is torn, and the silicone adhesive layer may be lifted from the plastic film substrate or may be cut while being stretched so as to pull a thread.

（式中Ｒは置換若しくは非置換の一価炭化水素基を表し、ｎは３０以上の整数である）で表されるジオルガノポリシロキサン、（ロ）１分子中にケイ素原子に結合している水素原子を少なくとも３個有すると共に、有機基として置換若しくは非置換の一価炭化水素基を有するオルガノハイドロジェンポリシロキサン、（ハ）加水分解性シリル基含有ビニル系及び／又はアクリル系共重合体及び（ニ）有機カルボン酸金属塩からなるプライマー組成物が提案されている。 As described above, in the case where the silicone adhesive has insufficient adhesion to a sheet-like substrate such as a plastic film, a method of previously applying a primer to the sheet-like substrate is employed. (Patent Document 1)
(B) General formula

(Wherein R represents a substituted or unsubstituted monovalent hydrocarbon group, and n is an integer of 30 or more), (b) bonded to a silicon atom in one molecule An organohydrogenpolysiloxane having at least three hydrogen atoms and having a substituted or unsubstituted monovalent hydrocarbon group as an organic group, (c) a hydrolyzable silyl group-containing vinyl-based and / or acrylic-based copolymer, and (D) A primer composition comprising an organic carboxylic acid metal salt has been proposed.

In JP-A-2002-338890 (Patent Document 2), (A) a diorganopolysiloxane having an alkenyl group at both ends of a molecular chain and having an average degree of polymerization of 500 to 2,000, A diorganopolysiloxane having a mole number of 0.001 to 0.005 mol per 100 g of the diorganopolysiloxane, (B) an organohydrogenpolysiloxane having at least two hydrogen atoms directly bonded to silicon atoms in one molecule; A primer composition for a silicone pressure-sensitive adhesive comprising (C) a platinum-based curing catalyst and (D) a reaction control agent has been proposed.
Examples thereof include a vinyl group content of 0.002 to 0.003 mol / 100 g, a degree of polymerization of about 450 to 1,300, and dimethylpolysiloxane and organohydrogenpolysiloxane having vinyl groups at both ends of the molecular chain. A primer composition comprising siloxane, a platinum-based curing catalyst, and an addition reaction control agent is disclosed. However, the organohydrogenpolysiloxane is only disclosed that the hydrogen atom content is 1.55 mol / 100 g, and its organic group, chemical structure, degree of polymerization, and viscosity are not disclosed at all.

In JP2010-184953 (Patent Document 3),
A plastic film through a cured product layer of an addition curable primer composition for a silicone adhesive, comprising the following components (A) to (D) on a silicone adhesive layer formed on a separator for a silicone adhesive: A silicone pressure-sensitive adhesive tape is disclosed in which a base material is laminated.
(A) Diorgano having an alkenyl group at both ends of the molecular chain, an average degree of polymerization of 100 or more and 1,000 or less, and an alkenyl group contained of 0.125 mol% or more and 2.5 mol% or less Polysiloxane,
(B) an organohydrogenpolysiloxane having at least two hydrogen atoms directly bonded to silicon atoms in one molecule;
(C) platinum-based curing catalyst,
(D) Reaction control agent.
In the specification, as component (B), methyl hydrogen polysiloxane in which both molecular chain ends represented by the formula Me ₃ SiO— [MeHSiO] ₄₀ —SiMe ₃ etc. are blocked with a trimethylsiloxy group, the formula Me ₃ SiO— _{[MeHSiO] 45 - [Me 2} SiO] 15 -SiMe 3 methylhydrogensiloxane-dimethylsiloxane copolymer with both molecular chain terminals blocked with trimethylsiloxy groups represented by like, branched methylhydrogenpolysiloxane is illustrated Has been.

Japanese Patent Publication No. 6-39584 JP 2002-338890 A JP 2010-184953 A

However, the present inventors have noticed that the adhesion of the silicone pressure-sensitive adhesive to various sheet-like substrates, particularly plastic film substrates, cannot be sufficiently improved even when the above-described primer composition is used. In particular, it has been found that heat-resistant plastic film substrates such as polyester films and polyimide films having excellent heat resistance have a problem that the adhesiveness of the silicone adhesive is poor.
In consideration of the above-mentioned problems, the present invention provides a primer composition for a silicone pressure-sensitive adhesive that can more firmly adhere both when a silicone pressure-sensitive adhesive is applied to a sheet-like substrate, particularly a plastic film substrate. The purpose is to provide. Another object of the present invention is to provide a laminate in which a silicone pressure-sensitive adhesive and a sheet-like substrate are firmly adhered, and a silicone pressure-sensitive adhesive tape in which a silicone pressure-sensitive adhesive and a plastic film tape are firmly adhered. To do.

As a result of intensive studies to achieve the above object, the present inventors have obtained a diorganopolysiloxane having an average degree of polymerization of 400 to 2,000 having an alkenyl group at both ends of the molecular chain,
The average degree of polymerization is about 100 to 500, and the formula R ³ HSiO _2/2 (R ³ is a monovalent hydrocarbon group or monovalent halogenated hydrocarbon group having 1 to 10 carbon atoms and having no aliphatic unsaturated bond) The above-mentioned problems can be solved by a primer composition for a silicone pressure-sensitive adhesive comprising an organohydrogenpolysiloxane having a high organohydrogensiloxy unit ( ^DH unit) content and a hydrosilylation reaction catalyst. The present invention has been found.

That is, the said subject can be solved by the primer composition for silicone adhesives containing the following (A) component-(C) component.
(A) Diorganopolysiloxane having an alkenyl group at both ends of a molecular chain represented by the following average structural formula (1): R ¹ R ² ₂ SiO (R ² ₂ SiO) _P SiR ² ₂ R ¹ (1)
(In the formula, R ¹ is an alkenyl group having 2 to 10 carbon atoms, and R ² is a monovalent hydrocarbon group or monovalent halogenated hydrocarbon group having 1 to 10 carbon atoms having no aliphatic unsaturated bond. And P + 2 is an average number in the range of 400-2000).
(B) Organohydrogenpolysiloxane represented by the following average composition formula (2) (R ³ ₃ SiO _1/2 ) _k (R ³ HSiO _2/2 ) _m (R ³ ₂ SiO _2/2 ) _n (R ³ SiO _3/2 ) _p (2)
(Wherein R ³ is a monovalent hydrocarbon group or monovalent halogenated hydrocarbon group having 1 to 10 carbon atoms having no aliphatic unsaturated bond, k is an average (2 + p) number, m Is an average number of 100 to 500, n and p are average numbers of 0 or more,
m, n, and p are numbers in a range satisfying the relationship of an average of 100 ≦ m + n + p ≦ 500 and 0.8 ≦ m / (m + n + p) ≦ 1. )
(C) Hydrosilylation reaction catalyst

Moreover, the said subject is diorganopolysiloxane which said (A) component has an alkenyl group in the both ends of the molecular chain whose average of P + 2 is 450-1500 in the said Formula (1),
The above-mentioned component (B) can be more preferably solved by a primer composition for a silicone pressure-sensitive adhesive which is a linear organohydrogenpolysiloxane represented by the following average structural formula (3).
R ³ ₃ SiO (R ³ HSiO _2/2 ) _m1 (R ³ ₂ SiO _2/2 ) _n1 SiR ³ ₃ (3)
(Wherein R ³ is a monovalent hydrocarbon group or monovalent halogenated hydrocarbon group having 1 to 10 carbon atoms having no aliphatic unsaturated bond, m1 is an average of 100 to 500, and n1 Is an average of 0 or more, and m1 and n1 are numbers in a range satisfying the relationship of average 100 ≦ m1 + n1 ≦ 500 and 0.9 ≦ m1 / (m1 + n1) ≦ 1.

In addition, the primer layer formed by curing the primer composition for a silicone pressure sensitive adhesive as described above is also used for a sheet-like base material in which adhesion of the silicone pressure sensitive adhesive is difficult, such as a polyester film or a polyimide film. Since the silicone pressure-sensitive adhesive can be firmly adhered, the sheet-like substrate, the primer layer obtained by curing the primer composition for the silicone pressure-sensitive adhesive on the sheet-like substrate, and the silicone formed on the primer layer The above problem can be satisfactorily solved by a laminate having an adhesive layer and a silicone adhesive tape in which a silicone adhesive layer is provided on a plastic film tape via a cured product layer of the primer composition.

The primer composition for a silicone pressure-sensitive adhesive of the present invention comprises a silicone pressure-sensitive adhesive, particularly a hydrosilylation-curable silicone pressure-sensitive adhesive or an organic peroxide-curable silicone pressure-sensitive adhesive, in a sheet-like substrate, preferably a plastic film, particularly heat resistant. When applied to a conductive plastic film substrate, both can be adhered more firmly. The laminate of the present invention comprises a silicone adhesive, particularly a hydrosilylation-curable silicone adhesive or an organic peroxide-curable silicone adhesive and a sheet-like substrate, preferably a plastic film substrate, particularly a heat-resistant plastic. The film substrate is firmly attached. The silicone adhesive tape of the present invention has a silicone adhesive, particularly a hydrosilylation-curable silicone adhesive or an organic peroxide-curable silicone adhesive, and a plastic film tape, preferably a heat-resistant plastic film tape. .

First, the primer composition for a silicone pressure-sensitive adhesive of the present invention will be described in detail.
The primer composition for silicone pressure-sensitive adhesives of the present invention has the effect of remarkably improving the adhesion between the silicone pressure-sensitive adhesive and the sheet-like substrate, and comprises the following components (A) to (C).
(A) Diorganopolysiloxane having an alkenyl group at both ends of a molecular chain represented by the following average structural formula (1): R ¹ R ² ₂ SiO (R ² ₂ SiO) _P SiR ² ₂ R ¹ (1)
(In the formula, R ¹ is an alkenyl group having 2 to 10 carbon atoms, and R ² is a monovalent hydrocarbon group or monovalent halogenated hydrocarbon group having 1 to 10 carbon atoms having no aliphatic unsaturated bond. And P + 2 is an average number in the range of 400-2000).
(B) Organohydrogenpolysiloxane represented by the following average composition formula (2) (R ³ ₃ SiO _1/2 ) _k (R ³ HSiO _2/2 ) _m (R ³ ₂ SiO _2/2 ) _n (R ³ SiO _3/2 ) _p (2)
(Wherein R ³ is a monovalent hydrocarbon group or monovalent halogenated hydrocarbon group having 1 to 10 carbon atoms having no aliphatic unsaturated bond, k is an average (2 + p) number, m Is an average of 100 to 500, n and p are average numbers of 0 or more, and m, n, and p satisfy the relationship of average 100 ≦ m + n + p ≦ 500 and 0.8 ≦ m / (m + n + p) ≦ 1. The number of ranges.),
(C) Hydrosilylation reaction catalyst

(A) A component is the main ingredient of the primer composition for silicone adhesives of this invention. The alkenyl group in the component (A) is crosslinked and cured by a hydrosilylation reaction with the silicon atom-bonded hydrogen atom in the component (B) by the catalytic action of the component (C).
Component (A) is a linear diorganopolysiloxane having an alkenyl group at both ends of the molecular chain, the molecular chain length is somewhat long, and an alkenyl group is present only at both ends of the molecular chain. The side chain-side chain hydrosilylation reaction does not occur. Therefore, by using together with (B) component, the adhesiveness of a silicone adhesive and a sheet-like base material can be improved notably.

In the average structural formula (1), R ¹ is an alkenyl group having 2 to 10 carbon atoms, preferably an alkenyl group having 2 to 6 carbon atoms, specifically, vinyl group, allyl group, butenyl group, hexenyl. Examples are groups. Among them, a vinyl group or a hexenyl group is preferable from the viewpoint of ease of production.

R ² is a monovalent hydrocarbon group or monovalent halogenated hydrocarbon group having 1 to 10 carbon atoms and having no aliphatic unsaturated bond. As the former, a linear or branched alkyl group such as a methyl group, an ethyl group, a propyl group, a pentyl group or an octyl group; a cycloalkyl group such as a cyclohexyl group; an aryl group such as a phenyl group, a tolyl group or a xylyl group; Examples include aralkyl groups such as benzyl group, α-methylstyryl group, and 2-phenylethyl group.
As monovalent halogenated hydrocarbon groups, monovalent fluorinated hydrocarbon groups, especially perfluoroalkyl groups, such as 3,3,3-trifluoropropyl groups, 4,4,4,3,3-pentafluorobutyl groups A monovalent chlorinated hydrocarbon group, for example a chloroalkyl group such as a 3-chloropropyl group and a chlorophenyl group such as a dichlorophenyl group;
Industrially, all R ² in the molecule is an alkyl group having 1 to 10 carbon atoms (provided that at least 50 mol% of all R ^{2 in} the molecule is a methyl group), particularly all R ^{2 in} the molecule. ² is preferably only a methyl group. Or it is preferable that all R < ² > in a molecule | numerator is a methyl group and a phenyl group (however, at least 50 mol% is a methyl group).
When all R ¹ in the molecule is a vinyl group and all R ² in the molecule is only a methyl group, the average structural formula (1) is
ViMe ₂ SiO (Me ₂ SiO) _P SiMe ₂ Vi (1-1)
(In the formula, Vi is a vinyl group, Me is a methyl group, and P + 2 is an average number of 400 to 2000).

P is the number of diorganosiloxy units represented by the formula R ² ₂ SiO _2/2 , and the total number of siloxane units represented by “P + 2” needs to be in the range of 400 to 2000 on average, and 450 to 1500 on average Is preferable, and an average range of 700 to 1300 is particularly preferable.
If “P + 2” is less than 400 on average, the cured product of the primer composition tends to fall off from the surface of the sheet-like substrate, and a sufficient effect as a primer cannot be obtained.
When “P + 2” is 400 or more and 2000 or less on average, the primer composition does not fall off after curing, and the effect of improving the adhesion becomes remarkable. When the average is 450 or more, particularly 700 or more and 2000 or less, the adhesion is improved. The improvement effect becomes more remarkable.
On the other hand, when “P + 2” exceeds 2000 on average, the adhesion between the silicone pressure-sensitive adhesive and the sheet-like substrate tends to decrease, and the adhesion improving effect tends to decrease.
The total number of siloxane units is almost equal to the average degree of polymerization, and the average degree of polymerization is calculated from the weight average molecular weight obtained by gel permeation chromatography (GPC) analysis based on a calibration curve created from a polystyrene standard sample. Can do. The same applies hereinafter.

The alkenyl group content of the component (A) is preferably 0.001 to 0.010 mol / 100 g, particularly preferably 0.002 to 0.006 mol / 100 g, from the viewpoint of the effect of improving adhesion. .

The component (B), which is an organohydrogenpolysiloxane represented by the average composition formula (2), is a crosslinking agent for the component (A) and is a component that characterizes the present invention. The component (A) is hydrosilylated by the catalytic action of the component (C) to crosslink the component (A).

The component (B) is a linear or branched organohydrogenpolysiloxane, and among all siloxane units, the number of organohydrogensiloxy units constituting the linear structure is in the range of 100 to 500 on average. The sum of the number of organohydrogensiloxy units, the number of diorganosiloxy units and the number of monoorganosiloxy units which are branched units is in the range of 100 to 500 on average, and a large number of silicon bonds are present in the side chain portion of the linear structure. Since it has a hydrogen atom, the silicone pressure-sensitive adhesive layer, particularly a hydrosilylation-curable silicone pressure-sensitive adhesive or an organic peroxide-curable silicone pressure-sensitive adhesive layer and a sheet-like base material, Adhesion with a plastic film substrate, particularly a heat-resistant plastic film substrate, is significantly improved.

In the organohydrogenpolysiloxane represented by the above average composition formula (2), R ³ ₃ SiO _1/2 is a triorganosiloxy unit (M unit) which is a structural unit at the end of the molecular chain,
R ³ HSiO _2/2 is an organohydrogensiloxy unit ( ^DH unit) that is a structural unit of a siloxane chain,
R ³ ₂ SiO _2/2 is a diorganosiloxy unit (D unit) that is a structural unit of a siloxane chain,
R ³ SiO _3/2 is an organosiloxy unit (T unit) which is a branch unit.

R ³ is a monovalent hydrocarbon group or monovalent halogenated hydrocarbon group having 1 to 10 carbon atoms not having an aliphatic unsaturated bond, and the same monovalent hydrocarbon group or monovalent halogenated group as R ¹ above. Examples are hydrocarbon groups.
Industrially, all R ³ in the molecule is an alkyl group having 1 to 10 carbon atoms (provided that at least 50 mol% of all R ^{3 in} the molecule is a methyl group), particularly only a methyl group. Preferably there is. Or all of R ³ is a methyl group and phenyl group in the molecule (except, at least 50 mol% of methyl groups is) is preferably.
When all R ³ in the molecule is only a methyl group, the average composition formula (2) is
(Me ₃ SiO _1/2 ) _k (MeHSiO _2/2 ) _m (Me ₂ SiO _2/2 ) _n (MeSiO _3/2 ) _p (2-1)
(In the formula, Me is a methyl group, k is an average number of (2 + p), m is an average number of 100 to 500, n and p are average numbers of 0 or more, and m, n, p Is an average of 100 ≦ m + n + p ≦ 500 and 0.8 ≦ m / (m + n + p) ≦ 1).

When p = 0 in the average composition formula (2), the organohydrogenpolysiloxane is linear, and the average structural formula R ³ ₃ SiO (R ³ HSiO _2/2 ) _m (R ³ ₂ SiO _2/2 ) _N SiR ³ ₃ (2-2)
(Wherein R ³ is the same group as described above, m is an average number of 100 to 500, n is an average number of 0 or more, and m and n are an average of 100 ≦ m + n ≦ 500 and 0.8 ≦. m / (m + n) ≦ 1 is the number of ranges satisfying the relationship.
In the average structural formula (2-2), when all R ³ are methyl groups, the average structural formula Me ₃ SiO (MeHSiO _2/2 ) _m (Me ₂ SiO _2/2 ) _n SiMe ₃ (2-2-1) )
(Wherein Me is a methyl group, and m and n are as described above).

When m and (m + n + p) are less than 100 on average, the adhesion between the silicone pressure-sensitive adhesive and the sheet-like substrate is lowered, and the adhesion improving effect is lowered. On the other hand, when (m + n + p) exceeds 500 on average, the organohydrogenpolysiloxane itself is easily gelled and is difficult to produce.
Here, in particular, m and (m + n + p) need to have an average of 100 or more. When m and (m + n + p) are about 90 on average, organohydrogen satisfying the relationship of 0.8 ≦ m / (m + n + p) ≦ 1 Even if polysiloxane is used, sufficient adhesion improvement effect cannot be realized.

When m / (m + n + p) is outside the above range (<0.8), the content of organohydrogensiloxy units ( ^DH units) in the molecule is insufficient, and the cured product of the primer composition is a sheet-like substrate. Particularly, since it falls off from the surface of the plastic film substrate, the adhesiveness of the silicone adhesive to the sheet-like substrate is deteriorated, and the effect of improving the adhesiveness is reduced. From the viewpoint of improving the adhesion between the silicone pressure-sensitive adhesive layer and the sheet-like substrate, m is preferably 100 to 430 on average, more preferably 100 to 400 on average, and m, n, and p are 0. It is preferable to satisfy the relationship of .90 ≦ m / (m + n + p) ≦ 1.0, more preferably 0.95 ≦ m / (m + n + p) ≦ 1.0, and the relationship of m / (m + n + p) = 1. It is particularly preferable to satisfy it.

As long as the above relationship is satisfied, k, m, n, and p are not particularly limited, but the component (B) is a straight chain in which the molecular chain is mainly composed of ^DH units in terms of the effect of improving adhesion. Alternatively, it preferably has a light branched structure, and in the average composition formula (2), p indicating the number of R ³ SiO _3/2 units (T units) is preferably 0 or 1. Here, k is 2 when p is 0, and 3 when p is 1. Further, n indicating the number of R ³ ₂ SiO _2/2 units (D units) is 0.9 to 90 when m is an average of 100 to 430, preferably an average of 100 to 400, and p is 0 or 1. ≦ m / (m + n + p) ≦ 1.0 is preferable, preferably 0.95 ≦ m / (m + n + p) ≦ 1.0, more preferably n = 0. Most preferred. )

In view of the effect of improving adhesion, it is most preferable that p = 0, and the component (B) is most preferably a linear organohydrogenpolysiloxane represented by the following formula (3).
R ³ ₃ SiO (R ³ HSiO _2/2 ) _m1 (R ³ ₂ SiO _2/2 ) _n1 SiR ³ ₃ (3)
(Wherein R ³ is the same group as described above, m1 is an average number of 100 to 500, n1 is an average of 0 or more, and m1 and n1 are 100 ≦ m1 + n1 ≦ 500 and 0.9 ≦ m1. / (M1 + n1) ≦ the number of ranges satisfying the relationship of 1)
Among these, m1 is an average of 100 to 430, preferably an average of 100 to 400, and m1 and n1 satisfy the relationship of 0.90 ≦ m1 / (m1 + n1) ≦ 1.0 in terms of adhesion improvement effect. More preferably, the number satisfies the relationship of 0.95 ≦ m1 / (m1 + n1) ≦ 1.0, and most preferably n1 = 0. When n1 = 0, 100 ≦ m1 + n1 ≦ 500 and m1 / (m1 + n1) = 1 are satisfied, and the component (B) is represented by the following formula (3-1).
R ³ ₃ SiO (R ³ HSiO _2/2 ) _m1 SiR ³ ₃ (3-1)
(Wherein R ³ and m1 are as defined above)

The blending amount of component (A) and component (B) is the ratio of the total number of moles of hydrogen atoms directly bonded to silicon atoms in component (B) to the number of moles of alkenyl groups in component (A) (hereinafter referred to as H / Vi). Is preferably 1 to 50, more preferably 8 or more and 20 or less in terms of adhesion improvement effect, and 10 or more and 15 or less. It is more desirable to do. If H / Vi is less than 1, the cured primer composition may not be sufficiently adhered to the sheet-like substrate, and if it exceeds 50, the temporal adhesion of the cured primer composition may be deteriorated.

The platinum-based curing catalyst of the component (C) promotes an addition reaction between the alkenyl group in the component (A) and the silicon atom-bonded hydrogen atom in the component (B), that is, a hydrosilylation reaction. This hydrosilylation reaction promoting catalyst includes chloroplatinic acid, alcohol solution of chloroplatinic acid, complex of chloroplatinic acid and olefin, complex of chloroplatinic acid and vinylsiloxane, complex of chloroplatinic acid and ketones, platinum Examples thereof include silica powder carrying platinum and platinum black. The amount of component (C) is not particularly limited as long as it is a catalytic amount, but the amount of platinum metal in the mass unit is 1 to 1000 ppm with respect to the total mass of component (A) and component (B). preferable. If it is less than 1 ppm, curing may be insufficient. If it is more than 1000 ppm, the usable time of the primer composition for a silicone pressure-sensitive adhesive may be shortened, and platinum-based catalysts are expensive. It is also disadvantageous economically.

In addition to the above components, it is preferable to add a hydrosilylation reaction inhibitor to the primer composition for a silicone pressure-sensitive adhesive of the present invention in order to improve storage stability at room temperature. Specific examples of the hydrosilylation reaction inhibitor include 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-penten-3-ol, and phenyl. Alkynyl alcohols such as butynol and 1-ethynyl-1-cyclohexanol; 3-methyl-3-penten-1-yne, 3-methyl-3-hexen-1-yne, 3,5-dimethyl-3-hexene Enyne compounds such as 1-yne), benzotriazole, methylvinylsiloxane cyclic, benzyl alcohol; maleates and fumarate, such as the well-known dialkyl maleates, dialkenyl maleates and dialkoxyalkyl fumarates and dialkyl fumarate, di Examples include alkenyl fumarate. The blending amount of the hydrosilylation reaction inhibitor is usually in the range of 0.001 to 5 parts by mass with respect to 100 parts by mass in total of the component (A) and the component (B).

An organic solvent is preferably blended so that the primer composition for a silicone pressure-sensitive adhesive of the present invention can be uniformly and thinly applied to a sheet-like substrate. The type and blending amount of the organic solvent are adjusted in consideration of the coating workability. Examples of the organic solvent include aromatic hydrocarbon solvents such as toluene, xylene and benzene, aliphatic hydrocarbon solvents such as heptane, hexane, octane and isoparaffin, ester solvents such as ethyl acetate and isobutyl acetate, and diisopropyl. Examples include ether solvents such as ether and 1,4-dioxane, chlorinated aliphatic hydrocarbon solvents such as trichlorethylene, perchloroethylene, and methylene chloride, solvent volatile oils, and the like. You may combine 2 or more types according to wettability etc.
The amount of the organic solvent blended is such that the mixture of the components (A) to (C) can be applied uniformly and thinly on the surface of the sheet-like substrate. It is 100-3000 mass parts per mass part.

The primer composition for a silicone pressure-sensitive adhesive of the present invention comprises the above-mentioned components (A) to (C) as essential components, but for the purpose of further improving the adhesion to the sheet-like substrate, silicon atoms in one molecule A trialkoxysilane having at least one epoxy group-containing organic group directly bonded to the organic group, or an organooligo having at least one epoxy group-containing organic group directly bonded to a silicon atom and at least three alkoxy groups directly bonded to a silicon atom in one molecule Siloxane may be blended. Two or more trialkoxysilanes or organooligosiloxanes having an epoxy group-containing organic group may be combined. The compounding amount of this component is preferably 10 parts by mass or less, particularly preferably 2 parts by mass or less, with respect to 100 parts by mass in total of the components (A) and (B). When it exceeds 10 mass parts, it will become disadvantageous for hardening of a primer composition. Furthermore, as long as the effects of the invention are not impaired, a trace amount or a small amount of a colorant may be blended.

The preparation method of the primer composition for silicone adhesives of this invention is not specifically limited. First, the (A) component, the (B) component and, if necessary, the organic solvent are uniformly mixed. Next, the hydrosilylation reaction inhibitor is preferably added to the mixture and mixed. If necessary, the trialkoxysilane or organooligosiloxane having the epoxy group-containing organic group is added and mixed. The component (C) is preferably added and mixed at the end or immediately before use of the primer composition.

The primer composition for a silicone pressure-sensitive adhesive according to the present invention is applied to the surface of a sheet-like substrate in order to improve the adhesion of the silicone pressure-sensitive adhesive layer to the sheet-like substrate, but further improves the adhesion. Therefore, as the sheet-like base material, a sheet-like base material that has undergone surface treatment such as other primer treatment, corona discharge treatment, etching treatment, plasma treatment, or the like may be used.

The primer composition for a silicone pressure-sensitive adhesive of the present invention is uniformly applied to a sheet-like substrate, and then cured by standing at room temperature, air drying, hot air drying or heat curing. The coating amount may be an amount sufficient to form a primer thin film on the surface of the sheet-like substrate, and is, for example, about 0.05 to 2.0 g / m ^2. This is not preferable because the adhesiveness between the adhesive and the silicone adhesive is inhibited. The temperature and time for heat curing vary depending on the type of substrate and the amount of coating, but are preferably selected at 80 to 180 ° C. for 120 to 15 seconds.

Examples of the sheet-like substrate include a plastic film, a polyolefin laminated paper, and a metal foil. A plastic film is preferable, and a heat resistant plastic film is more preferable.
Examples of the plastic film resin include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate (PEN), polyimide resins, polyimide ether resins, polyamide imide (PAI) resins, and polyether ether ketone (PEEK) resins. Heat-resistant resins such as liquid crystal polyarylate resin, polyether sulfone (PES) resin, polyphenylene sulfide resin; general-purpose thermoplastics such as ABC resin, polyamide resin, polycarbonate resin, polystyrene resin, polypropylene resin, polyethylene resin, polyvinyl chloride resin Resins; Thermosetting resins such as epoxy resins and phenol resins can be used.
The plastic film may be a laminate film formed by laminating a plurality of these plastic films.

As the silicone pressure-sensitive adhesive to be applied to the sheet-like substrate, that is, a silicone pressure-sensitive adhesive, known ones can be used, for example, an organic peroxide curing type cured with an organic peroxide, a platinum-based catalyst The hydrosilylation reaction-curing type and the condensation reaction-curing type are known. The primer composition for a silicone pressure-sensitive adhesive of the present invention generally has a hydrosilylation reaction curable silicone pressure-sensitive adhesive having a low crosslinking density, which is said to have poor adhesion to a sheet-like base material, and has a hydrosilyl adhesiveness to a sheet-like base material. It is also effectively used for an organic peroxide curable silicone pressure-sensitive adhesive which is said to be better than a chemical reaction curable silicone pressure-sensitive adhesive.
The silicone pressure-sensitive adhesive is composed of one or more siloxane components as described in, for example, US Pat. No. 5,30,0171 and US Pat. No. 4,591,622, and has sufficient adhesive strength. It is a material that can be adhered to a clean substrate simply by pressing lightly and can be peeled off if necessary. Generally, it consists of a crosslinkable diorganopolysiloxane, an organopolysiloxane resin composed of triorganosiloxy units and SiO _4/2 units, and a curing agent. Alternatively, it comprises a condensate of diorganopolysiloxane and organopolysiloxane resin on the left, and a curing agent.
The organic peroxide curable silicone pressure-sensitive adhesive usually contains a vinyl group-containing diorganopolysiloxane and is cured by the action of the organic peroxide at an elevated temperature.
The hydrosilylation reaction-curable silicone adhesive is usually produced by a hydrosilylation reaction between the vinyl group in the diorganopolysiloxane and the SiH group (silicon-bonded hydrogen atom) in the organohydrogenpolysiloxane by the action of a platinum-based catalyst. Harden.
The condensation reaction curable silicone pressure-sensitive adhesive is usually cured by a condensation reaction between silanol groups or hydrolyzable groups such as diorganopolysiloxane under the action of a condensation reaction catalyst.

The primer composition for a silicone pressure-sensitive adhesive according to the present invention comprises a primer layer formed by curing a primer composition for a silicone pressure-sensitive adhesive on a sheet-like substrate, and a silicone pressure-sensitive adhesive layer formed on the primer layer. It is useful for the manufacture of the laminated body provided. In particular, the silicone adhesive is firmly adhered to the surface of the plastic film substrate and is useful for producing a laminate having excellent adhesion durability. The primer composition for a silicone adhesive according to the present invention is used in a wide range of fields. It can utilize for manufacture of a laminated body.

The use of the laminate obtained by using the primer composition for a silicone adhesive of the present invention is not particularly limited, and is represented by a silicone adhesive tape and a silicone adhesive sheet. Examples of the adhesive tape include and are preferably a heat-resistant adhesive tape, an electrical insulating adhesive tape, a heat seal adhesive tape, a masking adhesive tape, and the like.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to the following Example. In the following Examples and Comparative Examples, “parts” indicates “parts by mass”, and ppm indicates mass ppm.

[Preparation of primer composition: Examples 1 to 11 and Comparative Examples 1 to 13]
(Vi polymer): 100 parts of dimethylpolysiloxane having vinyl groups at both ends of the molecular chain having an average molecular structure shown in Tables 1 to 7.
(SiH polymer): 2.5 parts of a linear or branched methyl hydrogen polysiloxane having a trimethylsiloxy terminal having an average molecular structure shown in Tables 1 to 7.
(Curing catalyst): Platinum-based catalyst (complex of chloroplatinic acid and 1,3-diethynyl-1,1,3,3-tetramethyldisiloxane) 100 ppm in terms of platinum,
0.66 parts of methylbutinol,
The primer composition used for an Example and a comparative example was prepared by throwing 900 parts of toluene and 1000 parts of isooctane into a mixer, and stirring it uniformly at normal temperature. In addition, H / Vi ratio of each primer composition is shown in Tables 1-7.

[Preparation of adhesive tape for evaluation: Examples 1 to 8, Comparative Examples 1 to 8]
(1) A polyethylene terephthalate film (PET) having a thickness of 50 μm was used as a plastic film which is a sheet-like substrate.
(2) A silicone pressure-sensitive adhesive for hydrosilylation reaction, that is, a pressure-sensitive adhesive (trade name: SD4593PSA (manufactured by Toray Dow Corning Co., Ltd.)) 100 parts, a SiH group-containing siloxane-based cross-linking agent ( Product name: BY24-741 (Toray Dow Corning Co., Ltd.) 0.75 parts, platinum-based catalyst (a complex of chloroplatinic acid and 1,3-diethynyl-1,1,3,3-tetramethyldisiloxane) A mixture of 100 ppm in terms of platinum and 12.5 parts of toluene was used.
(3) The primer composition was applied to the plastic film using a Mayer bar # 3 and cured by heating at 130 ° C. for 1 minute to form a primer layer. (However, the primer composition is not applied only in Comparative Example 8.)
(4) Next, a silicone adhesive was applied on the primer layer to a thickness of 30 μm (after evaporation of toluene and isooctane), cured by heating at 100 ° C. for 3 minutes, then cut to a width of 25 mm, A silicone adhesive tape having an adhesive layer was obtained.

[Adhesion Evaluation of Silicone Adhesive Tape by Tear Method: Examples 1-8, Comparative Examples 1-8]
The adhesion between the silicone adhesive layer and the plastic film tape in the silicone adhesive tape was evaluated by the tear method. That is, the evaluation was based on the degree of elongation of the silicone pressure-sensitive adhesive layer when the plastic film tape as the sheet-like substrate was torn. If the adhesion to the plastic film tape is good, the elongation of the silicone pressure-sensitive adhesive layer becomes short.
In a specific evaluation, a 1.5 mm length cut was made in the width direction of the pressure-sensitive adhesive tape obtained by the above method. Next, slowly apply force to the cut to tear the adhesive tape, stretch the silicone adhesive layer in the slit length direction, and between the plastic film tape when the silicone adhesive layer is completely cut, that is, the corner of the plastic film tape. The distance between the parts was measured and recorded. The distance between the plastic film tapes = the maximum distance that the silicone pressure-sensitive adhesive layer extends without being cut, that is, the maximum elongation.

Since the silicone adhesive layer has elasticity, if the adhesiveness between the silicone adhesive layer and the plastic film tape is small, the silicone adhesive layer can be extended a long distance by external force, but the silicone adhesive layer is plastic If the film tape is strongly adhered, the plastic film tape is broken in a short distance. That is, the shorter the distance between the plastic film tapes when the adhesive is completely cut, the higher the adhesion strength is evaluated.
Therefore, when tearing slowly in the slit length direction from the above incision,
The degree of elongation of the silicone pressure-sensitive adhesive layer that extends without being cut is> 100 mm.
The degree of elongation of the silicone pressure-sensitive adhesive layer that extends without being cut is 40 to 100 mm.
The degree of elongation is 25 to 40 mm, the smaller one is triangular,
The degree of elongation is 10 to 25 mm, and a slight one is round,
The degree of elongation was 0 to 10 mm, and no elongation or very little was indicated as a double circle.

[Examples 1 to 8, Comparative Examples 1 to 8: Effect of improving adhesion to hydrosilylation reaction-curable silicone adhesive]
When the silicone pressure-sensitive adhesive is a hydrosilylation reaction-curable silicone pressure-sensitive adhesive and the plastic film tape is a polyethylene terephthalate film tape, the results of evaluating the adhesion of the primer compositions according to the examples and comparative examples of the present invention are as follows. Tables 1 to 4 show.

In Tables 1 to 7, each siloxane unit is represented using the following abbreviations.
^Vi M: Vinyldimethylsiloxy unit M ^Vi : Vinyldimethylsiloxy unit M: Trimethylsiloxy unit D: Dimethylsiloxy unit ^DH : Methylhydrogensiloxy unit T: Methylsiloxy unit

As shown in Tables 1 and 2, in Examples 1 to 8, the adhesion improving effect of the primer composition is remarkable, especially ^DH is 100 or more, and D ^H / (D + D ^H + T In Example 1 to Example 5 in which the component (B) having a ratio of 0.9 or more was used, it was confirmed that the effect of improving the adhesion of the primer composition was extremely remarkable.
In addition, Examples 1 to 5 in which H / Vi is 10.0 or more have better adhesion improvement effects than Examples 6 to 8 in which H / Vi is 8.0 or more and less than 10. I was able to confirm that.
On the other hand, as shown in Tables 3 and 4, Comparative Examples 1 to 3 and Comparative Example 7 using SiH polymers having a short molecular chain length, that is, the component (B) having a ^DH of less than 100; D ^H / ( Comparative Example 2, Comparative Example 4 and Comparative Example 5 using Component (B) whose D + D ^H + T) is less than 0.8; vinyl polymer having a short molecular chain length, that is, component (A) of D ₃₂₈ In Comparative Example 6 and Comparative Example 7 used, it was confirmed that the adhesion improving effect of the primer composition was poor.
The first to third terms of the claims of the present application are supported by the above-described examples and comparative examples, and are clear.

The linear methyl hydrogen polysiloxanes disclosed in the specification of Patent Document 3 all have a ^DH of 45 or ^DH of 45, and D ^H / (D + D ^H + T) is less than 0.8, which corresponds to the above comparative example. Therefore, it can be said that the primer compositions of Examples 1 to 8 are remarkably superior in the adhesion improving effect as compared with the primer composition disclosed in Patent Document 3.

[Production and Evaluation of Evaluation Silicone Adhesive Tape: Examples 9 to 11 and Comparative Examples 9 to 13]
(1 ′) A 25 μm thick polyimide film (PI) cut into a 25 mm width was used as a plastic film as a sheet-like substrate.
(2 ′) Silicone adhesive composition for curing organic peroxide, that is, pressure-sensitive adhesive (trade name: 7406 VLO Adhesive (manufactured by Dow Corning Corporation)), benzoyl peroxide-containing paste catalyst (product) Name: Nyper BMT-K40 (manufactured by NOF Corporation, Nyper \ NYPER is a registered trademark of the company) 0.15 part and a mixture of 50 parts of toluene were used.
(3 ′) The primer composition was applied to one side of the plastic film tape using a Mayer bar # 3 and cured by heating at 130 ° C. for 1 minute to form a primer layer. (However, the primer composition is not applied only in Comparative Example 8.)
(4 ′) Next, the silicone pressure-sensitive adhesive composition was applied to a thickness of 30 μm (after evaporation of toluene and isooctane), heat-cured at 70 ° C. for 3 minutes, and 180 ° C. for 5 minutes, and cut to a width of 25 mm. A silicone pressure-sensitive adhesive tape having a silicone pressure-sensitive adhesive layer was obtained.

[Adhesion Evaluation of Silicone Adhesive Tape by Tear Method: Examples 9 to 11 and Comparative Examples 9 to 13]
The adhesion between the silicone pressure-sensitive adhesive layer and the polyimide film tape in the silicone pressure-sensitive adhesive tape was evaluated using the tear method, as with the adhesion for the hydrosilylation reaction-curable silicone pressure-sensitive adhesive.

[Examples 9 to 11, Comparative Examples 9 to 13: Effect of improving adhesion to organic peroxide-curing silicone adhesive]
When the silicone adhesive is an organic peroxide curable silicone adhesive and the plastic film tape is a polyimide film tape, the results of evaluating the adhesion of the primer compositions according to Examples and Comparative Examples of the present invention Tables 5 to 7 show. Abbreviations in the table are the same as those in Tables 1 to 4.
As shown in Tables 5 to 7, in Examples 9 to 11, the adhesion improving effect of the primer composition was remarkable, but in Comparative Examples 9 to 13, the adhesion of the primer composition was significant. The improvement effect was insufficient.
That is, the primer compositions of Examples 9 to 11 using the component (B) having ^DH of 100 or more and ^DH / (D + D ^H + T) of 0.9 or more are improved in adhesion. It was confirmed that the effect was remarkable.
On the other hand, short SiH polymer molecular chain length, i.e., ^{D H} is less than 100 (B) Comparative Example 9 using the component, Comparative Example ^{13; D H / (D +} D H + T) is less than 0.8 Comparative Example 10 and Comparative Example 11 using Component (B): Vinyl Polymer with a Short Molecular Chain Length, ie, Comparative Example 12 and Comparative Example 13 Using Component (A) of D ₃₂₈ , Both Primer Compositions It was confirmed that the effect of improving the adhesion was insufficient.

In Tables 6 and 7, when the maximum elongation of the silicone pressure-sensitive adhesive layer is 30 mm, the comparative example is that the sheet-like substrate is a polyimide film tape, and the organic peroxide curing This is because the type silicone pressure-sensitive adhesive generally has better adhesion to the plastic film tape than the hydrosilylation reaction curable type silicone pressure-sensitive adhesive.
The first to third terms of the claims of the present application are supported by the above-described examples and comparative examples, and are clear.

The linear methyl hydrogen polysiloxanes disclosed in the specification of Patent Document 3 all have a ^DH of 45 or ^DH of 45, and D ^H / (D + D ^H + T) is less than 0.8, which corresponds to the above comparative example. Therefore, it can be said that the primer compositions of Examples 9 to 11 are remarkably superior in the adhesion improving effect as compared with the primer composition disclosed in Patent Document 3.

The primer composition for a silicone pressure-sensitive adhesive of the present invention is useful for firmly adhering the silicone pressure-sensitive adhesive to a sheet-like substrate, particularly a plastic film substrate.
The laminate of the present invention is useful as an adhesive tape, a heat-resistant adhesive tape, an electrical insulating adhesive tape, a heat seal adhesive tape, a masking adhesive tape, and the like.
The silicone pressure-sensitive adhesive tape of the present invention is useful as a heat-resistant pressure-sensitive adhesive tape, an electrical insulating pressure-sensitive adhesive tape, a heat seal pressure-sensitive adhesive tape, a masking pressure-sensitive adhesive tape, and the like.

Claims (8)

The primer composition for silicone adhesives containing the following (A) component-(C) component.
(A) Diorganopolysiloxane having an alkenyl group at both ends of a molecular chain represented by the following average structural formula (1): R ¹ R ² ₂ SiO (R ² ₂ SiO) _P SiR ² ₂ R ¹ (1)
(In the formula, R ¹ is an alkenyl group having 2 to 10 carbon atoms, and R ² is a monovalent hydrocarbon group or monovalent halogenated hydrocarbon group having 1 to 10 carbon atoms having no aliphatic unsaturated bond. And P + 2 is an average number in the range of 400-2000).
(B) Organohydrogenpolysiloxane represented by the following average composition formula (2) (R ³ ₃ SiO _1/2 ) _k (R ³ HSiO _2/2 ) _m (R ³ ₂ SiO _2/2 ) _n (R ³ SiO _3/2 ) _p (2)
(Wherein R ³ is a monovalent hydrocarbon group or monovalent halogenated hydrocarbon group having 1 to 10 carbon atoms having no aliphatic unsaturated bond, k is an average (2 + p) number, m Is an average number of 100 to 500, n and p are average numbers of 0 or more,
m, n, and p are numbers in a range satisfying the relationship of an average of 100 ≦ m + n + p ≦ 500 and 0.8 ≦ m / (m + n + p) ≦ 1. ),
(C) Hydrosilylation reaction catalyst The primer composition for silicone pressure-sensitive adhesives according to claim 1, wherein the component (B) is a linear organohydrogenpolysiloxane represented by the following average structural formula (3).
R ³ ₃ SiO (R ³ HSiO _2/2 ) _m1 (R ³ ₂ SiO _2/2 ) _n1 SiR ³ ₃ (3)
(Wherein R ³ is a monovalent hydrocarbon group or monovalent halogenated hydrocarbon group having 1 to 10 carbon atoms having no aliphatic unsaturated bond, m1 is an average of 100 to 500, and n1 Is an average of 0 or more, and m1 and n1 are numbers in a range satisfying the relationship of average 100 ≦ m1 + n1 ≦ 500 and 0.9 ≦ m1 / (m1 + n1) ≦ 1. 2. The primer composition for a silicone pressure-sensitive adhesive according to claim 1, wherein, in the average structural formula (1), P + 2 is a number in the range of 450 to 1500 on average. The primer layer formed by hardening | curing the primer composition for silicone adhesives of any one of Claims 1-3 on a sheet-like base material and the said sheet-like base material, and the silicone formed on the said primer layer A laminate comprising an adhesive layer. The laminate according to claim 4, wherein the silicone pressure-sensitive adhesive is a hydrosilylation reaction-curable silicone pressure-sensitive adhesive. The laminate according to claim 4, wherein the sheet-like substrate is a plastic film substrate. The silicone pressure-sensitive adhesive tape comprising the laminate according to claim 4, wherein the sheet-like substrate is a plastic film tape. The silicone adhesive tape according to claim 7, wherein the plastic film tape is a heat-resistant plastic film tape.