Silicone adhesive composition, adhesive tape, and adhesive film

Abstract

Provided is a silicone adhesive composition containing the following components (A) through (D): (A) 10-80 parts by mass of a linear or branched organopolysiloxane in which the alkenyl group content is 0.0001-0.03 mol / 100 g and the ratio of the total number of aryl group-containing organic groups to the total number of groups bonded to silicon atoms is 0.1-15%; (B) 20-90 parts by mass of an organopolysiloxane resin having an R3 3SiO1 / 2 unit and an SiO4 / 2 unit and a molar ratio, expresses as (R3 3SiO1 / 2 unit) / (SiO4 / 2 unit), of 0.6-1.0 (in the formula, R3 are each independently a substituted or unsubstituted C1-C10 monovalent hydrocarbon group, a hydroxyl group, or a C1-C6 alkoxy group), and which has hydroxyl groups bonded to silicon atoms in an amount of 0.001-0.100 mol / 100 g and C1-C6 alkoxy groups bonded to silicon atoms in an amount of 0.001-0.100 mol / 100 g, with the total of the hydroxyl groups and the alkoxy groups being 0.001-0.140 mol / 100g, and has a weight average molecular weight of 1,000-6,500 (provided that a total amount of the components (A) and (B) is 100 parts by mass); (C) an organic hydrogen polysiloxane having three or more hydrogen atoms bonded to a silicon atom in one molecule, present in an amount such that the ratio of the total number of SiH groups in the component (C) to a total number of the alkenyl groups in the component (A) is 0.5-30.0; and (D) a catalyzing amount of a platinum group metal-based catalyst.

Description

Silicone pressure-sensitive adhesive composition, pressure-sensitive adhesive tape, and pressure-sensitive adhesive film

[0001] The present invention relates to a silicone pressure-sensitive adhesive composition, and more specifically to a silicone pressure-sensitive adhesive composition that provides an adhesive layer that exhibits excellent adhesion to substrates even without primer treatment and that leaves no adhesive residue even after high-temperature heating, and that exhibits excellent heat resistance, as well as a pressure-sensitive adhesive tape and pressure-sensitive adhesive film that include an adhesive layer made of a cured product of the pressure-sensitive adhesive composition.

[0002] The polysiloxane that makes up the silicone pressure-sensitive adhesive has excellent heat resistance, cold resistance, weather resistance, electrical insulation, and chemical resistance, and is therefore used in harsh environments such as heat-resistant pressure-sensitive adhesive tapes, electrical insulating pressure-sensitive adhesive tapes, masking tapes for manufacturing processes, temporary fixing tapes, heat-sealing tapes, and flame-retardant mica tapes.

[0003] Silicone pressure-sensitive adhesives exhibit excellent wettability with a variety of adherends, and are adhesive to silicone resins, polyolefins, fluororesins, silicone rubber, silicone release paper, etc., which are difficult to adhere to with organic resin-based pressure-sensitive adhesives such as acrylic pressure-sensitive adhesives, rubber pressure-sensitive adhesives, and urethane pressure-sensitive adhesives. For this reason, pressure-sensitive adhesive tapes using silicone pressure-sensitive adhesives are considered suitable for use when bonding or fixing silicone rubber members to other members, for example.

[0004] Conventionally, adhesive tapes have been used that are made by coating and laminating a silicone adhesive on a plastic film substrate such as a polyester film or a polyimide film. Such adhesive tapes are usually wound into rolls, but when they are unwound forcefully during use, the silicone adhesive layer may peel off from the substrate. Furthermore, when cutting the adhesive tape, only the substrate is torn, and the silicone adhesive layer is not cut but stretched like strings, or the silicone adhesive layer may lift off from the substrate. Thus, conventional silicone adhesive layers have the problems of peeling off from the substrate and stringiness.

[0005] Therefore, a method has been adopted in which a carbon functional silane-based primer composition or a primer composition using a specific organopolysiloxane is applied to the substrate, and then the silicone pressure-sensitive adhesive is treated to improve the adhesion between the film substrate and the silicone pressure-sensitive adhesive layer.

[0006] However, no matter which primer composition is used, satisfactory adhesion may not be obtained. Furthermore, in order to perform the primer treatment, it is necessary to apply an adhesive after the primer treatment. For this purpose, it is necessary to use a special coating device that applies the primer and the adhesive layer in-line, or to perform a two-step coating in which an adhesive is applied again to a substrate that has already been coated with a primer, both of which are disadvantageous in terms of productivity and cost.

[0007] On the other hand, a substrate adhesion improver that is directly added to a silicone pressure-sensitive adhesive composition has been proposed. Patent Document 1 describes that the addition of an adhesion improver containing an aryl group of a specific structure and an SiH group improves the adhesion of the silicone pressure-sensitive adhesive composition to the substrate. Furthermore, Patent Document 2 reports that the incorporation of an organohydrogenpolysiloxane having an aryl group-containing organic group provides excellent substrate adhesion and suppresses changes in adhesive strength over time.

[0008] Furthermore, Patent Document 3 proposes a silicone pressure-sensitive adhesive composition in which an alkenyl group-containing organopolysiloxane having a viscosity of 20 to 500 mPa·s is added to the silicone pressure-sensitive adhesive composition to improve adhesion to substrates. Patent Document 4 proposes improving adhesion to substrates by using a specific alkenyl group-containing silicone oil in combination with an alkenyl group-containing organopolysiloxane resin.

[0009] JP 2015-178584 A, WO 2019 / 142779, JP 2009-256542 A, WO 2020 / 026844

[0010] In the above Patent Documents 1 and 2, the silicone compositions are limited to those with low adhesive strength, since they are intended for use as protective films for various displays. ３ SiO １／２ Units and SiO ４／２Even when applied to silicone compositions with high adhesive strength, such as those containing a large amount of organopolysiloxane resin units, adhesion to substrates did not improve. Furthermore, the adhesion improver also led to adhesive residue on the adherend after heating at high temperatures.

[0011] Patent Documents 3 and 4 describe silicone compositions with high adhesive strength, but the adhesive strength and adhesion to substrates are insufficient, and furthermore, when heated at high temperatures, adhesive residue is left on the adherend, so the heat resistance is also low.

[0012] As described above, there are no silicone pressure sensitive adhesives that combine substrate adhesion and heat resistance with high adhesive strength.

[0013] The present invention has been made in view of the above circumstances, and relates to a silicone pressure-sensitive adhesive composition with high adhesive strength. More specifically, it is an object of the present invention to provide a silicone pressure-sensitive adhesive composition that provides an adhesive layer that has excellent adhesion to substrates even without primer treatment and excellent heat resistance and leaves no adhesive residue even after high-temperature heating, and to provide a pressure-sensitive adhesive tape and pressure-sensitive adhesive film that include an adhesive layer made of a cured product of the pressure-sensitive adhesive composition.

[0014] As a result of extensive research conducted by the present inventors to achieve the above object, it was discovered that an addition reaction curable silicone pressure sensitive adhesive composition contains (A) an organopolysiloxane containing a specific amount of alkenyl group and aryl group-containing organic group, (B) an R ３ ３ SiO １／２ Units and SiO ４／２ The present inventors have found that the above object can be achieved by blending specific amounts of an organopolysiloxane resin (C) having units in a specific ratio and further having a specific amount of functional groups, and an organohydrogenpolysiloxane, respectively, and have completed the present invention.

[0015] That is, the present invention provides [1] a silicone pressure-sensitive adhesive composition comprising the following components (A) to (D): (A) 10 to 80 parts by mass of a linear or branched organopolysiloxane having one or more alkenyl groups and one or more aryl group-containing organic groups per molecule, the alkenyl group content being 0.0001 to 0.03 mol / 100 g, and the ratio of the total number of aryl group-containing organic groups to the total number of groups bonded to silicon atoms being 0.1 to 15%, (B) R ３ ３ SiO １／２ Units and SiO ４／２ units, (R ３ ３ SiO １／２ Unit) / (SiO ４／２ The organopolysiloxane resin (wherein R ３ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, a hydroxyl group, or an alkoxy group having 1 to 6 carbon atoms; the organopolysiloxane resin has 20 to 90 parts by mass of hydroxyl groups bonded to silicon atoms in an amount of 0.001 to 0.100 mol / 100 g, alkoxy groups bonded to silicon atoms in an amount of 0.001 to 0.100 mol / 100 g having 1 to 6 carbon atoms, the total amount of the hydroxyl groups bonded to silicon atoms and the alkoxy groups bonded to silicon atoms in an amount of 0.001 to 0.140 mol / 100 g, and a weight average molecular weight (Mw) of 1,000 to 6,500 in terms of standard polystyrene as measured by gel permeation chromatography (GPC), provided that the total amount of components (A) and (B) is 100 parts by mass; (C) an organohydrogenpolysiloxane having three or more silicon-bonded hydrogen atoms per molecule, in an amount such that the ratio of the total number of SiH groups in component (C) to the total number of alkenyl groups in component (A) is 0.5 to 30.0; and (D) a catalytic amount of a platinum group metal catalyst.

[0016] The present invention further provides the silicone pressure-sensitive adhesive composition, further comprising at least one of the following structures [2] to [5]: [2] The silicone pressure-sensitive adhesive composition, wherein the component (B) does not contain an alkenyl group or contains an alkenyl group in an amount of less than 0.005 mol / 100 g. [3] The silicone pressure-sensitive adhesive composition, wherein the component (A) is represented by the following formula (1): (In the formula, R １ are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, provided that R １ at least one of the alkenyl-containing organic groups having 2 to 10 carbon atoms and the aryl-containing organic groups having 6 to 10 carbon atoms, the alkenyl group content in the organopolysiloxane is 0.0001 to 0.03 mol / 100 g, and the group R bonded to the silicon atom １ the ratio of the total number of aryl group-containing organic groups to the total number of aryl groups is 0.1 to 15%, and a is a positive number from 100 to 20,000. [4] The silicone pressure-sensitive adhesive composition, wherein component (C) is represented by the following formula (3): (In the formula, R ４ are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms and having no aliphatic unsaturated bonds; j is 0 or 1; k and m are numbers such that 1≦k≦100, 0≦m≦60, 3≦2j+k≦100, and 3≦k+m+2≦150; and a hydrogen atom bonded to a silicon atom and a group R bonded to a silicon atom ４(wherein the ratio of the total number of hydrogen atoms bonded to silicon atoms to the total number of hydrogen atoms bonded to silicon atoms is 20 to 50%). [5] The silicone pressure-sensitive adhesive composition as described above, wherein the mass ratio of component (A) to component (B) is 25 / 75 to 60 / 40. The present invention further provides a cured product obtained by curing the silicone pressure-sensitive adhesive composition as described in any of items [1] to [5] above. The present invention further provides a pressure-sensitive adhesive tape comprising a substrate and an adhesive layer formed on at least one surface of the substrate, wherein the adhesive layer is the cured product described above. The present invention further provides a pressure-sensitive adhesive film comprising a substrate and an adhesive layer formed on at least one surface of the substrate, wherein the adhesive layer is the cured product described above.

[0017] An adhesive tape or film having an adhesive layer formed by curing the silicone adhesive composition of the present invention has high adhesive strength and excellent substrate adhesion and heat resistance. Therefore, the adhesive tape or film of the present invention can be suitably used as a heat-resistant silicone tape, a tape for masking electronic components, or an adhesive tape or film for protecting the screen of electronic devices such as touch panels or for use in the manufacturing process.

[0018] The silicone pressure-sensitive adhesive composition of the present invention will now be described in more detail.

[0019] [Component (A)] Component (A) is a linear or branched organopolysiloxane containing one or more alkenyl groups and one or more aryl-containing organic groups per molecule, preferably at least one of a silicon-bonded aryl group and a silicon-bonded aralkyl group.

[0020] The component (A) may be used alone or in combination of two or more types.

[0021] Component (A) may be any oil- or gum-like organopolysiloxane, preferably a gum-like organopolysiloxane. The viscosity at 25°C of oil-like organopolysiloxanes is preferably 1,000 mPa·s or more, more preferably 10,000 mPa·s or more, and particularly preferably 50,000 mPa·s or more. For gum-like organopolysiloxanes, the viscosity of a 30% by mass solution in toluene is preferably 1,000 to 200,000 mPa·s, more preferably 5,000 to 150,000 mPa·s, even more preferably 10,000 to 120,000 mPa·s, and particularly preferably 15,000 to 100,000 mPa·s. Viscosities below the lower limit may make uniform coating difficult, or the resulting adhesive layer may exhibit reduced adhesive strength, substrate adhesion, or heat resistance. If the viscosity exceeds the upper limit, the viscosity of the composition will be so high that it will be difficult to stir and mix, and workability may be impaired. In this specification, viscosity (mPa s) is a value measured at 25°C using a B-type rotational viscometer in accordance with JIS K7117-1 (the same applies hereinafter).

[0022] The amount of alkenyl groups contained in component (A) is 0.0001 to 0.03 mol per 100 g of organopolysiloxane, more preferably 0.0002 to 0.02 mol / 100 g, more preferably 0.0003 to 0.01 mol / 100 g, and even more preferably 0.0005 to 0.005 mol / 100 g. If the amount is less than the lower limit, the curing properties may be reduced, and the adhesiveness to the substrate and heat resistance of the resulting adhesive layer may be reduced. If the amount is greater than the upper limit, the crosslink density of the resulting adhesive layer may be increased, and the adhesive strength and heat resistance may be reduced. The amount of alkenyl groups is determined by the amount of the alkenyl group in the deuterated chloroform solution. １ H-NMR and ２９ This can be determined by a known structural analysis method using Si-NMR (the same applies hereinafter).

[0023] The organopolysiloxane (A) is preferably represented by the following formula (1): In the formula, R １ are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, provided that R１ at least one of the alkenyl-containing organic groups having 2 to 10 carbon atoms and the aryl-containing organic groups having 6 to 10 carbon atoms, the alkenyl group content in the organopolysiloxane is 0.0001 to 0.03 mol / 100 g, and the group R bonded to the silicon atom １ The ratio of the total number of aryl group-containing organic groups to the total number of groups is 0.1 to 15%, and a is a positive number of 100 to 20,000.

[0024] When the above formula (1) has a hydroxyl group, R １ The ratio of the number of hydroxyl groups to the total number of groups is preferably 10% or less, more preferably 0.0001 to 5%, and even more preferably 0.001 to 1%. That is, the amount of hydroxyl groups in component (A) is preferably 0.15 mol / 100g or less, and particularly preferably 0.00001 to 0.03 mol / 100g. By having hydroxyl groups, component (A) can undergo a condensation reaction with component (B), which will be described later. The amount of SiOH groups is determined by the amount of hydroxyl groups in the deuterated chloroform solution. １ H-NMR and ２９ This can be determined by a known structural analysis method using Si-NMR (the same applies hereinafter).

[0025] In formula (1), R １ are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms; R １ At least one of the above is an alkenyl-containing organic group having 2 to 10 carbon atoms and an aryl-containing organic group having 6 to 10 carbon atoms. The alkenyl-containing organic group has 2 to 10 carbon atoms, preferably 2 to 8 carbon atoms, and may contain an oxygen atom. Examples include alkenyl groups such as vinyl, allyl, hexenyl, and octenyl, and cycloalkenylalkyl groups such as cyclohexenylethyl. Examples of the alkenyl-containing monovalent hydrocarbon group that may contain an oxygen atom include acryloylalkyl groups and methacryloylalkyl groups such as acryloylpropyl, acryloylmethyl, methacryloylpropyl, and methacryloylmethyl. The methylene chain may contain an ether bond, for example, -(CH ２ ) ２ -O-CH２ -CH=CH ２ , -(CH ２ ) ３ -O-CH ２ -CH=CH ２ Examples include:

[0026] The monovalent hydrocarbon group other than the alkenyl group-containing organic group is a monovalent hydrocarbon group having 1 to 10 carbon atoms and no aliphatic unsaturated bond. Examples include alkyl groups preferably having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, and butyl, cycloalkyl groups preferably having 5 to 8 carbon atoms, such as cyclohexyl, aryl groups preferably having 6 to 10 carbon atoms, such as phenyl and tolyl, aralkyl groups preferably having 7 to 10 carbon atoms, such as benzyl, and monovalent hydrocarbon groups having 1 to 10 carbon atoms in which some or all of the hydrogen atoms bonded to carbon atoms have been substituted with hydroxy groups, cyano groups, halogen atoms, alkoxy groups, alkoxysilyl groups, polyoxyalkylene groups, epoxy groups, carboxyl groups, or the like, such as hydroxypropyl, cyanoethyl, 3-chloropropyl, 3,3,3-trifluoropropyl, 3,3,4,4,5,5,6,6,6-nonafluorohexyl, methoxypropyl, ethoxypropyl, and γ-glycidoxypropyl groups. Of these, a methyl group or a phenyl group is preferred.

[0027] The component (A) is a compound in which an aryl group-containing organic group is bonded to a silicon atom (i.e., R １ The ratio (%) of the number of aryl group-containing organic groups to the total number of aryl groups is 0.1 to 15%. It is preferably 0.3 to 13%, more preferably 0.6 to 11%, and even more preferably 1 to 9%. The lower limit of the ratio of the number of aryl group-containing organic groups is preferably 1.1% or more, more preferably 1.3% or more. If the ratio is less than the lower limit or exceeds the upper limit, the adhesive strength, substrate adhesion, or heat resistance of the resulting adhesive layer may decrease. The ratio of the number of aryl group-containing organic groups is determined by the ratio (%) of the number of aryl group-containing organic groups in a deuterated chloroform solution. １ H-NMR and ２９ This can be determined by a known structural analysis method using Si-NMR (the same applies hereinafter).

[0028] In formula (1), a is preferably 100 to 20,000, more preferably 500 to 15,000, even more preferably 1,000 to 13,500, and even more preferably 2,000 to 12,000. If a is less than the above lower limit, uniform coating may be difficult, and the adhesiveness to the substrate and heat resistance of the resulting adhesive layer may be reduced. If a exceeds the above upper limit, the viscosity of the composition may become very high, making it difficult to stir and mix, and other workability problems may result.

[0029] The component (A) is preferably an organopolysiloxane represented by the following formula (2). In the formula, R ２ are each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 10 carbon atoms that does not have a hydroxyl group or an aliphatic unsaturated bond, X is an alkenyl group-containing organic group of 2 to 10 carbon atoms, b is a number from 1 to 3, c is a number from 1 to 3, d is a number from 0 to 2, e is a number from 0 to 2, f is a number from 0 to 2, g is a number from 0 to 2, d+e+f+g=2, h is a number of 0 or greater, c×f+h≧1, i is a number of 100 or greater, and h+i satisfies 100≦h+i≦20,000.

[0030] In formula (2), R ２ are each independently a hydroxyl group or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms that does not have an aliphatic unsaturated bond. For example, R １ Examples of monovalent hydrocarbon groups other than the alkenyl-containing organic groups exemplified above include those mentioned above. Among these, a methyl group or a phenyl group is preferred.

[0031] X is an alkenyl-containing monovalent organic group having 2 to 10 carbon atoms, preferably 2 to 8 carbon atoms, and may contain an oxygen atom. １ Examples of the alkenyl group-containing organic group include those mentioned above. Among them, a vinyl group is preferred.

[0032] In formula (2), b is a number from 1 to 3, preferably 1. c is a number from 1 to 3, preferably 1. d is a number from 0 to 2, preferably 0 to 1.5, more preferably 0 to 1.0. e is a number from 0 to 2, preferably 0 to 1, more preferably 0 to 0.5, and even more preferably 0. f is a number from 0 to 2, preferably 0.5 to 2, more preferably 1.0 to 2.0. g is a number from 0 to 2, preferably 0 to 1.5, more preferably 0 to 1.0, and even more preferably 0. h is a number of 0 or more, preferably 0 to 500, more preferably 0 to 100, and even more preferably 0 to 50. i is a number of 100 or more, preferably 500 to 15,000, more preferably 1,000 to 13,500, and even more preferably 2,000 to 12,000. c×f+h is 2 or more, preferably 2 to 500, more preferably 2 to 100, and even more preferably 2 to 50. h+i is 100 to 20,000, preferably 500 to 15,000, more preferably 1,000 to 13,500, and even more preferably 2,000 to 12,000.

[0033] Examples of component (A) include, but are not limited to, the following: In the following formulas, Me, Vi, and Ph represent a methyl group, a vinyl group, and a phenyl group, respectively. The bonding order of each siloxane unit shown in parentheses is not limited to the following: In each of the following formulas, the total number of siloxane repeating units is an average value. (z1+z2+z3+z4+z5=2, 100≦z6+z7+z8≦20,000) (100≦z6+z7≦20,000) (100≦z6+z7≦20,000) (1≦z8, 100≦z6+z7+z8≦20,000) (z1+z5=2, 1≦z8, 100≦z6+z7+z8≦20,000) (z1+z3=2, 1≦z3+z8, 100≦z6+z7+z8≦20,000) (z1+z2=2, 1≦z8, 100≦z6+z7+z8≦20,000) (z1+z4=2, 1≦z4×3+z8, 100≦z6+z7+z8≦20,000)

[0034] The blending amount of component (A) is preferably from 0.05 to 75 mass %, more preferably from 0.1 to 70 mass %, and even more preferably from 0.15 to 65 mass %, based on the total mass of the silicone pressure-sensitive adhesive composition including the optional components described below.

[0035] The silicone composition of the present invention may further contain, in combination with component (A), a linear or branched organopolysiloxane (A') that has one or more alkenyl groups per molecule and is free of aryl group-containing organic groups and SiH groups.

[0036] The component (A') is represented, for example, by the following formula (1'). (In the formula, R １ ' are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, provided that R １ a' is not an aryl group-containing organic group, and a' is a positive number of 10 or more.

[0037] Component (A') may be an oily or crude rubber organopolysiloxane. If it is an oily organopolysiloxane, its viscosity at 25°C is preferably 1,000 mPa·s or more, more preferably 10,000 mPa·s or more, and particularly preferably 50,000 mPa·s or more. If it is a crude rubber-like organopolysiloxane, the viscosity of a 30% by mass solution in toluene is preferably 1,000 to 200,000 mPa·s, more preferably 5,000 to 150,000 mPa·s, even more preferably 10,000 to 120,000 mPa·s, and particularly preferably 15,000 to 100,000 mPa·s.

[0038] In formula (1'), a' is a positive number of 10 or greater, and may be any value that allows the organopolysiloxane to have the above-mentioned viscosity. Preferably, a' is 100 to 20,000, preferably 500 to 15,000, more preferably 1,000 to 13,500, and even more preferably 2,000 to 12,000. R １ ' is, for example, R １Examples of monovalent hydrocarbon groups other than the aryl group-containing organic groups exemplified above include those mentioned above. Among these, a methyl group or a vinyl group is preferred.

[0039] The content of component (A') is preferably 70% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, based on the total mass of components (A) and (A'). The lower limit of component (A') may be 0% by mass.

[0040] Furthermore, the total number of groups bonded to silicon atoms in components (A) and (A') (for example, R １ and R in formula (1′) １ The amount is preferably such that the ratio (%) of the total number of aryl group-containing organic groups to the total number (sum of (a) and (b)) of the aryl group-containing organic groups is 0.1 to 15%, more preferably 0.3 to 12%, even more preferably 0.6 to 6%, and even more preferably 1 to 4%. If the amount is within the above range, the adhesive strength, substrate adhesion, or heat resistance of the resulting adhesive layer may be improved.

[0041] The blending amount of component (A') is preferably 0 to 50 mass %, more preferably 0 to 40 mass %, and even more preferably 0 to 30 mass %, based on the total mass of the silicone pressure-sensitive adhesive composition including the optional components described below. Component (A') may not be included.

[0042] [Component (B)] Component (B) is R ３ ３ SiO １／２ Units and SiO ４／２ units, R ３ ３ SiO １／２ Units / SiO ４／２ The organopolysiloxane resin has a molar ratio of units of 0.60 to 1.0, preferably 0.65 to 0.95, and more preferably 0.70 to 0.90. If the molar ratio is less than the above lower limit or exceeds the above upper limit, the adhesive strength, substrate adhesion, or heat resistance of the resulting adhesive layer may decrease. ３ ３ SiO １／２ Units / SiO ４／２ The molar ratio of the unit is that of a deuterated chloroform solution. １ H-NMR and ２９This can be determined by a known structural analysis method using Si-NMR (the same applies hereinafter).

[0043] The component (B) may be used alone or in combination of two or more.

[0044] R ３ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, a hydroxyl group, or an alkoxy group having 1 to 6 carbon atoms. Examples include alkyl groups preferably having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, and butyl; cycloalkyl groups preferably having 5 to 8 carbon atoms, such as cyclohexyl; aryl groups preferably having 6 to 10 carbon atoms, such as phenyl and tolyl; aralkyl groups preferably having 7 to 10 carbon atoms, such as benzyl; alkenyl groups preferably having 2 to 8 carbon atoms, such as vinyl, allyl, and hexenyl; and monovalent hydrocarbon groups having 1 to 10 carbon atoms in which some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon groups have been substituted with hydroxy groups, cyano groups, halogen atoms, alkoxy groups, alkoxysilyl groups, polyoxyalkylene groups, epoxy groups, carboxyl groups, or the like, such as hydroxypropyl, cyanoethyl, 3-chloropropyl, 3,3,3-trifluoropropyl, 3,3,4,4,5,5,6,6,6-nonafluorohexyl, methoxypropyl, ethoxypropyl, and γ-glycidoxypropyl groups. Of these, methyl and phenyl groups are preferred, with methyl being particularly preferred.

[0045] Component (B) is preferably an organopolysiloxane resin that does not contain alkenyl groups, or may contain alkenyl groups, but the total amount of alkenyl groups contained in the resin is preferably less than 0.005 mol / 100 g. The total amount of alkenyl groups in the organopolysiloxane resin is more preferably less than 0.003 mol / 100 g, and even more preferably less than 0.001 mol / 100 g. Most preferably, component (B) does not contain alkenyl groups.

[0046] The component (B) is R ３ ３ SiO １／２ Units and SiO ４／２ Although the organopolysiloxane resin essentially contains the R unit, it may contain the R unit within a range that does not impair the properties of the present invention.３ ２ SiO ２／２ Units and R ３ SiO ３／２ Unit (R ３ is as described above). More preferably, ３ ３ SiO １／２ Units and the above SiO ４／２ It is an organopolysiloxane resin consisting of units.

[0047] Component (B) contains siloxane units (silanol group-containing units) having a hydroxyl group bonded to a silicon atom and siloxane units (alkoxy group-containing units) having an alkoxy group having 1 to 6 carbon atoms bonded to a silicon atom. The amount of silanol group-containing units is such that the hydroxyl group content of component (B) is 0.001 to 0.100 mol / 100g, preferably 0.005 to 0.095 mol / 100g, more preferably 0.010 to 0.090 mol / 100g, and even more preferably 0.020 to 0.085 mol / 100g. If the hydroxyl group content exceeds 0.100 mol / 100g, the adhesive strength, substrate adhesion, or heat resistance of the resulting adhesive layer may decrease, or the curability may decrease.

[0048] The amount of the alkoxy group-containing units is such that the alkoxy group content is 0.001 to 0.100 mol / 100 g of component (B), preferably 0.003 to 0.090 mol / 100 g, more preferably 0.005 to 0.080 mol / 100 g, and even more preferably 0.007 to 0.070 mol / 100 g. If the alkoxy group content exceeds 0.100 mol / 100 g, the adhesive strength, substrate adhesion, or heat resistance of the resulting adhesive layer may decrease, or the curability may decrease.

[0049] The above-mentioned SiOH group content and alkoxy group content are determined by the １ H-NMR and ２９ This can be determined by a known structural analysis method using Si-NMR (the same applies hereinafter).

[0050] Furthermore, the total amount of the silanol group-containing units and alkoxy group-containing units, as the sum of the hydroxyl group content and alkoxy group content, in component (B) is an amount that is 0.001 to 0.140 mol / 100 g, preferably 0.010 to 0.120 mol / 100 g, more preferably 0.050 to 0.11 mol / 100 g, and even more preferably 0.070 to 0.105 mol / 100 g.

[0051] Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, and a phenoxy group. ３ ２ (OH)SiO １／２ Unit, R ３ (OH) ２ SiO １／２ Unit, R ３ (OH)SiO ２／２ Units: (OH)SiO ３／２ The alkoxy group-containing unit is a unit represented by R ３ ２ (OR')SiO １／２ Unit, R ３ (OR') ２ SiO １／２ Unit, R ３ (OR')SiO ２／２ Units, (OR')SiO ３／２ (OR' are each independently an alkoxy group having 1 to 6 carbon atoms, as exemplified above). ３ ３ SiO １／２ Units and SiO ４／２ When the unit is SiO ４／２ It can be bonded to a silicon atom from the unit.

[0052] Component (B) has a weight-average molecular weight of 1,000 to 6,500. The weight-average molecular weight is preferably 1,500 to 6,000, with an upper limit of less than 6,000, more preferably 2,000 to 5,750, and even more preferably 2,500 to 5,500, with an upper limit of less than 5,000. If the weight-average molecular weight is less than the lower limit or exceeds the upper limit, the adhesive strength, substrate adhesion, or heat resistance of the resulting adhesive layer may be reduced. The weight-average molecular weight can be determined as the weight-average molecular weight converted into polystyrene by gel permeation chromatography (GPC) analysis using toluene as the developing solvent. In the present invention, the weight-average molecular weight (Mw) is a value measured by GPC (gel permeation chromatography) analysis using polystyrene as the standard under the following conditions. (Measurement conditions) GPC measurement device: HLC-8320 (manufactured by Tosoh Corporation) Detector: differential refractive index detector (RI) Measurement solvent: toluene Flow rate: 0.35 mL / min GPC columns: (passed in the following order) TSKgel Guardcolumn SuperHZ-L (4.6 mm I.D. × 2 cm × 1) TSKgel SuperHZ4000 (4.6 mm I.D. × 15 cm × 1) TSKgel SuperHZ3000 (4.6 mm I.D. × 15 cm × 1) TSKgel SuperHZ2000 (4.6 mm I.D. × 15 cm × 2) (all manufactured by Tosoh Corporation) Measurement temperature: 40°C Sample injection amount: 10 μL (toluene solution with a silicone concentration of 0.5 wt%)

[0053] The blending amount of component (B) is preferably 0.1 to 85 mass %, more preferably 0.2 to 80 mass %, and even more preferably 0.3 to 75 mass %, based on the total mass of the silicone pressure-sensitive adhesive composition including the optional components described below.

[0054] The mass ratio of component (A) to component (B) is 10 / 90 to 80 / 20, preferably 20 / 80 to 70 / 30, more preferably 25 / 75 to 60 / 40, and even more preferably 30 / 70 to 55 / 45. If the mass ratio is less than the lower limit or exceeds the upper limit, the adhesive strength, substrate adhesion, or heat resistance of the resulting adhesive layer may decrease.

[0055] The silicone pressure-sensitive adhesive composition of the present invention is ３ ３ SiO １／２ Units and SiO ４／２ Units (wherein R ３ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, a hydroxyl group, or an alkoxy group having 1 to 6 carbon atoms, and ３ applies), and (R ３ ３ SiO １／２ Unit) / (SiO ４／２ The silicone pressure-sensitive adhesive composition may further comprise an alkenyl group-containing organopolysiloxane resin having a molar ratio (expressed as a function of mol / 100 g) of 0.5 to 1.5, preferably 0.6 to 1.3, and more preferably 0.7 to 1.0, containing alkenyl groups at 0.005 mol / 100 g or greater, preferably 0.005 to 0.5 mol / 100 g, and having a weight-average molecular weight of 1,000 to 10,000, preferably 1,250 to 8,000, and more preferably 1,500 to 6,000. However, the content of the alkenyl group-containing organopolysiloxane resin is preferably 25% by mass or less, based on the total mass of the silicone pressure-sensitive adhesive composition. The content of the alkenyl group-containing organopolysiloxane resin is more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on the total mass of the silicone pressure-sensitive adhesive composition. The lower limit may be 0% by mass.

[0056] The content of the organopolysiloxane resin having the alkenyl group in an amount of 0.005 mol / 100 g or more is R ３ SiO １／２ Units and SiO ４／２ The content of the organopolysiloxane resin having alkenyl groups in an amount of 0.005 mol / 100 g or more is preferably 25% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, relative to the total amount of the organopolysiloxane resin having alkenyl groups, and the lower limit may be 0% by mass. The silicone pressure-sensitive adhesive composition of the present invention is most preferably an embodiment that does not contain the organopolysiloxane resin having alkenyl groups in an amount of 0.005 mol / 100 g or more.

[0057] [Component (C)] Component (C) is an organohydrogenpolysiloxane having three or more silicon-bonded hydrogen atoms (SiH groups) per molecule.

[0058] The organohydrogenpolysiloxane (C) may be used alone or in combination of two or more types.

[0059] The average degree of polymerization of the siloxane in component (C) is preferably 150 or less, more preferably 3 to 120, even more preferably 5 to 100, and even more preferably 10 to 80.

[0060] The SiH groups in component (C) undergo an addition reaction with the alkenyl groups in component (A) and optional component (A') to harden and form an adhesive layer. The amount of component (C) is such that the ratio of the total number of SiH groups in component (C) to the total number of alkenyl groups in component (A) is 0.5 to 30, preferably 1.0 to 20, more preferably 1.5 to 10, and even more preferably 2 to 8. The amount is preferably 0.01 to 10 parts by mass, preferably 0.03 to 5 parts by mass, and even more preferably 0.05 to 3 parts by mass, per 100 parts by mass of the total of components (A), (B), and optional component (A'). If the number ratio or amount is less than the above-mentioned lower limit or exceeds the above-mentioned upper limit, the adhesive strength, substrate adhesion, or heat resistance of the resulting adhesive layer may be reduced.

[0061] The component (C) may be linear, branched, or cyclic, or may be a mixture thereof. Examples of the component (C) include R ４ ２ HSiO １／２ Unit, R ４ HSiO ２／２ Units, and HSiO ３／２ and optionally further comprises at least one of R ４ ３ SiO １／２ Unit, R ４ ２ SiO ２／２ Unit, R ４ SiO ３／２ units, and SiO ４／２ Examples include polymers or copolymers comprising at least one of the units４ are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms and no aliphatic unsaturated bond. ４ ２ HSiO １／２ Unit or R ４ HSiO ２／２ The total number of units per molecule is preferably 3 to 100, more preferably 5 to 80, more preferably 7 to 70, and even more preferably 10 to 60. If the number of SiH groups is less than the above lower limit or exceeds the above upper limit, the curability may decrease, or the adhesive strength, substrate adhesion, or heat resistance of the resulting adhesive layer may decrease.

[0062] The above R ４ are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms and no aliphatic unsaturated bond. Examples of the monovalent hydrocarbon group include alkyl groups preferably having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, and butyl groups; cycloalkyl groups preferably having 5 to 8 carbon atoms, such as cyclohexyl groups; aryl groups preferably having 6 to 10 carbon atoms, such as phenyl and tolyl groups; aralkyl groups preferably having 7 to 10 carbon atoms, such as benzyl groups; and monovalent hydrocarbon groups having 1 to 10 carbon atoms in which some or all of the hydrogen atoms bonded to carbon atoms have been substituted with hydroxy groups, cyano groups, halogen atoms, alkoxy groups, alkoxysilyl groups, polyoxyalkylene groups, epoxy groups, carboxyl groups, or the like, such as hydroxypropyl groups, cyanoethyl groups, 3-chloropropyl groups, 3,3,3-trifluoropropyl groups, 3,3,4,4,5,5,6,6,6-nonafluorohexyl groups, methoxypropyl groups, ethoxypropyl groups, and γ-glycidoxypropyl groups. Among these, R ４ is preferably an alkyl group or an aryl group, more preferably a methyl group, an ethyl group, a propyl group or a phenyl group, and even more preferably a methyl group or a phenyl group.

[0063] Component (C) preferably has a viscosity at 25°C of 1 to 2,000 mPa·s, and more preferably 2 to 1,000 mPa·s.

[0064] Component (C) is preferably a linear organohydrogenpolysiloxane represented by the following formula (3). (In the formula, R ４ are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms and no aliphatic unsaturated bonds; j is 0 to 1; k and m are numbers such that 1≦k≦100 and 0≦m≦60; 3≦2j+k≦100; and 3≦k+m+2≦150.

[0065] In the above formula (3), R ４ are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms and not having an aliphatic unsaturated bond, and ４ Preferably, R ４ is preferably an alkyl group or an aryl group, more preferably a methyl group, an ethyl group, a propyl group or a phenyl group, and even more preferably a methyl group or a phenyl group.

[0066] With regard to j, k, and m, k is a number from 1 to 100, preferably from 3 to 90, more preferably from 5 to 80, even more preferably from 7 to 70, and even more preferably from 10 to 60. m is a number from 0 to 60, preferably from 0 to 30, more preferably from 0 to 20, and even more preferably from 0 to 10. j is 0 to 1, and 2j + k satisfies 3 to 100, preferably from 4 to 90, more preferably from 5 to 80, even more preferably from 7 to 70, and even more preferably from 10 to 60. k + m + 2 satisfies 3 to 150, preferably from 5 to 120, more preferably from 7 to 100, even more preferably from 9 to 70, and even more preferably from 10 to 60.

[0067] In addition, the hydrogen atom bonded to the silicon atom and the group R bonded to the silicon atom ４ The ratio of the total number of hydrogen atoms bonded to silicon atoms to the total number of silicon atoms (hereinafter referred to as the ratio of SiH groups) is preferably 20 to 50%, more preferably 25 to 49%, and even more preferably 30 to 48%.

[0068] Examples of component (C) include, but are not limited to, the following: In the following formulas, Me and Ph represent a methyl group and a phenyl group, respectively. The bonding order of each siloxane unit shown in parentheses is not limited to the following: In each of the following formulas, the total number of siloxane repeating units is an average value. (5≦z12+2≦100) (3≦z12+2≦100) (1≦z11≦60, 3≦z12≦100, 6≦z11+z12+2≦150) (1≦z11≦60, 1≦z12≦98, 4≦z11+z12+2≦150) (0≦z9, 0≦z10, 0≦z11, 3≦z12, 1≦z14, and the average degree of polymerization of siloxane is 150 or less.) (0≦z9, 0≦z10, 0≦z11, 3≦z12, 1≦z15, and the average degree of polymerization of siloxane is 150 or less.) (0≦z9, 0≦z10, 0≦z11, 3≦z12, 1≦z14, 1≦z15, and the average degree of polymerization of siloxane is 150 or less.) (3≦z12≦100, 1≦z13≦60, 6≦z12+z13+2≦150) (1≦z12≦100, 1≦z13≦60, 4≦z12+z13+2≦150) (3≦z12≦100, 1≦z16≦60, 6≦z12+z16+2≦150) (1≦z11≦60, 3≦z12≦100, 1≦z13≦60, 7≦z11+z12+z13+2≦150) (1≦z11≦60, 1≦z12≦100, 1≦z13≦60, 5≦z11+z12+z13+2≦150)

[0069] The blend amount of component (C) is preferably 0.00005 to 8% by mass, more preferably 0.00010 to 5.0% by mass, and even more preferably 0.00050 to 3.0% by mass, based on the total amount of the silicone pressure-sensitive adhesive composition including optional components described below.

[0070] In the present invention, component (C) may be either an organohydrogenpolysiloxane (C1) that does not have an aryl group-containing organic group bonded to a silicon atom, or an organohydrogenpolysiloxane (C2) that has an aryl group-containing organic group bonded to a silicon atom, or a combination of these. The aryl group-containing organic group is preferably at least one of an aryl group and an aralkyl group bonded to a silicon atom. More preferably, it is an aryl group preferably having 6 to 10 carbon atoms, such as a phenyl group or a tolyl group, or an aralkyl group preferably having 7 to 10 carbon atoms, such as a benzyl group, and more preferably a phenyl group. The organohydrogenpolysiloxane (C2) that has an aryl group-containing organic group bonded to a silicon atom is preferably an organohydrogenpolysiloxane that has three or more hydrogen atoms bonded to a silicon atom per molecule and has an aryl group-containing organic group bonded to a silicon atom. More preferably, it is an organohydrogenpolysiloxane represented by the above formula (3) and has at least one R ４ is an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms, preferably an aryl group having 6 to 10 carbon atoms, and more preferably a phenyl group.

[0071] In the organohydrogenpolysiloxane (C2) having an aryl group-containing organic group, the ratio of the total number of aryl groups to the total number of silicon-bonded hydrogen atoms and silicon-bonded groups (i.e., the ratio of aryl group-containing organic groups) is preferably 0.1% to 40%, more preferably 1 to 30%, and even more preferably 1 to 15%.

[0072] As described above, the present invention is characterized in that component (A) contains the above-mentioned specific amount of aryl group-containing organic groups. In embodiments of the present invention that include organohydrogenpolysiloxane (C2), it is preferable that [percentage of aryl group-containing organic groups in component (C2)] - [percentage of aryl group-containing organic groups in component (A)] < 15.0. More preferably, this difference is less than 10.0, more preferably less than 5.0, even more preferably 1.0 or less, even more preferably less than 0, and even more preferably -0.1 or less.

[0073] As described above, the component (C) of the present invention is either one selected from the group consisting of an organohydrogenpolysiloxane (C1) that does not have an aryl group-containing organic group bonded to a silicon atom and an organohydrogenpolysiloxane (C2) that has an aryl group-containing organic group bonded to a silicon atom, or a combination of the organohydrogenpolysiloxane (C1) and the organohydrogenpolysiloxane (C2). When used in combination, the amount of the organohydrogenpolysiloxane (C2) is preferably 0.1 to 50 mass%, more preferably 0.5 to 30 mass%, and even more preferably 1.0 to 20 mass%, based on the total amount of the organohydrogenpolysiloxane (C1) and the organohydrogenpolysiloxane (C2). In a particularly preferred embodiment of the silicone pressure-sensitive adhesive composition of the present invention, component (C) is a single system of any one selected from the above-mentioned organohydrogenpolysiloxane (C1) and the above-mentioned organohydrogenpolysiloxane (C2), and the most preferred embodiment is one in which component (C) consists solely of the above-mentioned organohydrogenpolysiloxane (C1).

[0074] [Component (D)] Component (D) is a catalyst for promoting the addition reaction between component (A), optional component (A'), and component (C). Any catalyst that promotes the so-called hydrosilylation reaction can be used, and known platinum group metal catalysts can be used. Examples of platinum group metal catalysts include platinum, palladium, rhodium, ruthenium, and iridium catalysts, with platinum catalysts being particularly preferred. Examples of platinum catalysts include chloroplatinic acid, alcohol solutions or aldehyde solutions of chloroplatinic acid, reaction products of chloroplatinic acid with alcohols, and complexes of chloroplatinic acid or platinum with various olefins or vinylsiloxanes. Component (D) may be used alone or in combination of two or more.

[0075] The amount of component (D) to be blended may be a catalytic amount. A catalytic amount is an amount effective for promoting the addition reaction with component (A), optional component (A'), and component (C). To obtain a good adhesive layer, the amount is 1 to 5,000 ppm, preferably 5 to 500 ppm, and more preferably 10 to 200 ppm, calculated as the mass of platinum group metal relative to the total mass of components (A), (B), (C), and optional component (A'). Within the above range, the adhesive strength, substrate adhesion, or heat resistance of the resulting adhesive layer may be improved.

[0076] Part or all of component (A), component (B), and optional component (A') may be subjected to a condensation reaction in advance. Specifically, the alkoxy groups or hydroxyl groups of component (A), optional component (A'), and component (B) may be subjected to a hydrolysis-condensation reaction or condensation reaction in advance to obtain a condensation reaction product, which may then be mixed with the other components. Alternatively, the alkoxy groups or hydroxyl groups of component (A) and component (B) may be subjected to a hydrolysis-condensation reaction or condensation reaction in advance to obtain a condensation reaction product, which may then be mixed with the other components. Alternatively, the alkoxy groups or hydroxyl groups of optional component (A') and component (B) may be subjected to a hydrolysis-condensation reaction or condensation reaction in advance to obtain a condensation reaction product, which may then be mixed with the other components.

[0077] To carry out the condensation reaction, a mixture of component (A) and / or component (A') dissolved in a solvent such as toluene and component (B) is reacted at room temperature (25°C) or under heat using one or more condensation catalysts, such as acids, bases, or organic acid metal salts, and neutralized as necessary. The reaction is preferably carried out so that the total amount of hydroxyl groups and alkoxy groups in the SiOH groups (silanol groups) in the condensation reaction product is 0.001 to 0.140 mol / 100 g. Therefore, the silicone pressure-sensitive adhesive composition of the present invention can be a composition containing the product obtained by the condensation reaction of component (A) and / or component (A') with component (B), as well as the aforementioned components (C) and (D). Performing the condensation reaction in advance can improve the adhesive strength, substrate adhesion, or heat resistance of the resulting cured product, or can inhibit migration of the silicone component to the adherend.

[0078] Examples of the basic condensation catalyst used in the reaction include metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, and calcium hydroxide; carbonates such as sodium carbonate and potassium carbonate; bicarbonates such as sodium bicarbonate and potassium bicarbonate; metal alkoxides such as sodium methoxide and potassium butoxide; organic metals such as butyllithium; potassium silanolate; ammonia gas, aqueous ammonia, methylamine, ethylamine, propylamine, hexylamine, butanolamine, butylamine, dimethylamine, diethylamine, diethanolamine, dipropylamine, dibutylamine, dihexylamine, ethylamylamine, imidazole, propylhexylamine, trimethylamine, triethylamine, tripropylamine, tripropanolamine, pyridine, N-methylimidazole, methylpropylhexylamine, dodecylamine phosphate, tetramethylguanidine, and nitrogen compounds and salts thereof such as diazabicyclononane. Among these, ammonia gas or aqueous ammonia is preferred.

[0079] The temperature for the condensation reaction can be 10 to 150° C., but is usually from room temperature (25° C.) to the reflux temperature of the organic solvent. The reaction time is not particularly limited, but may be from 0.5 to 20 hours, preferably from 1 to 16 hours.

[0080] Furthermore, after the reaction is completed, a neutralizing agent may be added to neutralize the basic catalyst, if necessary. Examples of the neutralizing agent include acidic gases such as hydrogen chloride and carbon dioxide; organic acids such as acetic acid, octylic acid, and citric acid; and mineral acids such as hydrochloric acid, sulfuric acid, and phosphoric acid. When ammonia gas, aqueous ammonia, or a low-boiling amine compound is used as the alkaline catalyst, the neutralizing agent may be distilled off by passing an inert gas such as nitrogen through the system.

[0081] [Optional Component (E)] Component (E) is an addition reaction inhibitor and is an optional component. It can be added before heat curing, for example, when preparing the silicone pressure-sensitive adhesive composition or when applying the pressure-sensitive adhesive composition to a substrate, to prevent the treatment liquid containing the pressure-sensitive adhesive composition from thickening or gelling. Examples of the component (E) include various organic nitrogen compounds, organic phosphorus compounds, organic silicon compounds, acetylene compounds, unsaturated carboxylic acid esters, oxime compounds, etc.

[0082] More specifically, examples of the acetylene-based compounds include acetylene alcohols such as 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentyn-3-ol, 2-phenyl-3-butyn-2-ol, and 1-ethynylcyclohexanol; acetylene compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; 3-methyl-3-trimethylsiloxy-1-butyne, 3-methyl-3-trimethylsiloxy-1-pentyne, 3,5-dimethyl-3-trimethylsiloxy-1-hexyne, and 1-ethynyl-1-trimethylsiloxysilane; Examples of the component (E) include reaction products of acetylene compounds such as cyclohexane and bis(2,2-dimethyl-3-butynoxy)dimethylsilane with chlorosilanes, alkoxysilanes, siloxanes, or hydrogensilanes, vinylsiloxanes such as 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane and 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, unsaturated carboxylic acid esters such as diallyl maleate, dimethyl maleate, diallyl fumarate, and diethyl fumarate, organic nitrogen compounds such as benzotriazole, other organic phosphorus compounds, and oxime compounds. Component (E) may be used alone or in combination of two or more types.

[0083] The amount of component (E) blended is in the range of 0 to 8.0 parts by mass per 100 parts by mass of the total of (A), (B), (C), and optional (A'). When blended, the amount is preferably in the range of 0.01 to 8.0 parts by mass, and more preferably in the range of 0.05 to 5.0 parts by mass. If the blended amount exceeds 8.0 parts by mass, the curability of the resulting composition may decrease. If the blended amount is 0.01 part by mass or more, the effect of reaction control is sufficiently exhibited.

[0084] [Other Optional Components] In addition to the above-mentioned components, other components can be optionally added to the silicone pressure-sensitive adhesive composition of the present invention. The amount of other components may be in accordance with that of conventionally known silicone pressure-sensitive adhesives, and may be appropriately adjusted within a range that does not impair the effects of the present invention. For example, non-reactive organopolysiloxanes such as polydimethylsiloxane and polydimethyldiphenylsiloxane; antioxidants such as phenols, quinones, amines, phosphorus, phosphite, sulfur, and thioethers; light stabilizers such as triazoles and benzophenones; flame retardants such as phosphate esters, halogens, phosphorus, and antimony; antistatic agents such as cationic surfactants, anionic surfactants, and nonionic surfactants; dyes; pigments; antifoaming agents; fillers; leveling agents; adhesion improvers such as silane coupling agents; thickeners; photopolymerization initiators; reactive diluents, and solvents for reducing viscosity during coating.

[0085] Examples of the solvent include aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane, heptane, octane, isooctane, decane, cyclohexane, methylcyclohexane, and isoparaffin, hydrocarbon solvents such as industrial gasoline, petroleum benzine, and solvent naphtha, ketone solvents such as acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, methyl isobutyl ketone, diisobutyl ketone, acetonylacetone, and cyclohexanone, ester solvents such as ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, and isobutyl acetate, and diethyl Examples of solvents that can be used include ether solvents such as diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, 1,2-dimethoxyethane, and 1,4-dioxane, solvents having an ester and an ether moiety such as 2-methoxyethyl acetate, 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, and 2-butoxyethyl acetate, and siloxane solvents such as hexamethyldisiloxane, octamethyltrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tris(trimethylsiloxy)methylsilane, and tetrakis(trimethylsiloxy)silane. These can be used alone or in appropriate combinations of two or more. When a solvent is added, the amount thereof is preferably 10 to 20,000 parts by mass, more preferably 25 to 10,000 parts by mass, and even more preferably 50 to 1,000 parts by mass, per 100 parts by mass of the total of components (A), (B), and (C) and optional component (A'). The silicone pressure-sensitive adhesive composition of the present invention can also be a solventless type.

[0086] [Method of Producing the Composition] The silicone pressure-sensitive adhesive composition of the present invention can be prepared by mixing and dissolving the above-mentioned components. From the standpoint of pot life, a preferred preparation method is to uniformly mix components (A), (B), and (C), optional component (A'), if necessary component (E), and other optional components in advance, and then add component (D) immediately before use. As mentioned above, component (A) and / or optional component (A') and component (B) may be subjected to a condensation reaction in advance.

[0087] The silicone pressure-sensitive adhesive composition of the present invention can be applied to various substrates and cured under specified conditions to obtain a silicone adhesive layer. The silicone pressure-sensitive adhesive composition of the present invention can be suitably used, for example, as an adhesive tape, adhesive sheet, or adhesive film having a substrate and an adhesive layer made of a cured product of the composition laminated on at least one side of the substrate.

[0088] [Substrate] The substrate may be selected from paper, plastic film made of plastic, glass, metal, cloth, etc. Examples of paper include fine paper, coated paper, art paper, glassine paper, polyethylene-laminated paper, kraft paper, Japanese paper, synthetic paper, etc. Examples of plastic films include polyethylene film, polypropylene film, polyester film, polyimide film, polyamide film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, polycarbonate film, polytetrafluoroethylene film, polystyrene film, ethylene-vinyl acetate copolymer film, ethylene-vinyl alcohol copolymer film, triacetyl cellulose film, polyether ether ketone film, polyphenylene sulfide film, etc. There are no particular limitations on the thickness or type of glass, and it may be chemically strengthened or the like. Glass fiber can also be used, and the glass fiber may be used alone or in combination with other resins. Examples of cloth include natural fiber cloth, synthetic fiber cloth, and artificial leather, and examples of metal include aluminum foil, copper foil, gold foil, silver foil, and nickel foil.

[0089] To further improve the adhesion between these substrates and the silicone adhesive layer, the substrate may be subjected to a primer treatment, corona treatment, etching treatment, sandblasting treatment, or plasma treatment.

[0090] The surface of the substrate opposite to the adhesive layer surface may be surface-treated to prevent scratches, stains, fingerprints, glare, reflection, static electricity, etc. The adhesive layer may be applied to the substrate before the surface treatment, or the adhesive layer may be applied after the surface treatment.

[0091] Examples of the scratch prevention treatment (hard coating treatment) include treatment with an acrylate-based, silicone-based, oxetane-based, inorganic-based, or organic-inorganic hybrid hard coating agent.

[0092] Examples of the antifouling treatment include treatment with an antifouling agent such as a fluorine-based, silicone-based, ceramic-based, or photocatalytic-based agent.

[0093] Examples of antireflection treatments include wet treatments using a fluorine-based, silicone-based, or other antireflection agent, and dry treatments using vapor deposition or sputtering. Examples of antistatic treatments include treatments using surfactant-based, silicone-based, organoboron-based, conductive polymer-based, metal oxide-based, or vapor-deposited metal-based antistatic agents.

[0094] [Method for producing adhesive tape and adhesive film] The coating method may be performed using a known coating method, such as a comma coater, lip coater, roll coater, die coater, knife coater, blade coater, rod coater, bar coater, kiss coater, gravure coater, screen coating, dip coating, or cast coating.

[0095] The coating amount is determined appropriately depending on the application, but typically it is an amount that results in a silicone adhesive layer having a thickness of 1 to 2,000 μm, preferably 2 to 1,000 μm, and especially 3 to 500 μm after curing.

[0096] The curing conditions for the silicone pressure-sensitive adhesive composition are preferably, but not limited to, 70 to 250° C. for 10 seconds to 10 minutes.

[0097] The pressure-sensitive adhesive tape or pressure-sensitive adhesive film of the present invention may be produced by directly applying the silicone pressure-sensitive adhesive composition of the present invention to a substrate as described above and curing the composition to form a silicone adhesive layer, or by a transfer method in which the composition is applied to a release-coated release film or release paper and cured to form a silicone adhesive layer, and then the silicone adhesive layer is laminated to the above-mentioned substrate.

[0098] [Adhesive Strength Range] The silicone pressure-sensitive adhesive composition of the present invention is characterized in that the cured layer obtained by curing the composition via a hydrosilylation reaction is adhesive. The adhesive layer of the present invention has the above-mentioned configuration and exhibits adhesive strength sufficient for practical use, so that it can be used in place of known silicone pressure-sensitive adhesives as desired.

[0099] More specifically, for a pressure-sensitive adhesive tape having a 30 μm thick adhesive layer obtained by curing the silicone pressure-sensitive adhesive composition of the present invention laminated on a 25 μm thick polyimide film, the average force required to peel the pressure-sensitive adhesive tape from a stainless steel plate at an angle of 180° at a speed of 300 mm / min according to JIS Z0237 is preferably 2.0 N / 25 mm or more, more preferably 3.0 to 15.0 N / 25 mm, more preferably 4.0 to 14.0 N / 25 mm, and even more preferably 5.0 to 12.0 N / 25 mm. Note that the above thickness (30 μm) is the thickness of the cured layer itself, which serves as a standard for objectively defining the adhesive strength of the cured layer according to the present invention, and it goes without saying that the silicone pressure-sensitive adhesive composition of the present invention can be used as a cured layer or adhesive layer of any thickness, not limited to 30 μm.

[0100] [Uses of Adhesive Tapes and Adhesive Films] Adhesive tapes or films having an adhesive layer formed by curing the silicone adhesive composition of the present invention have strong adhesive strength, excellent substrate adhesion, and excellent heat resistance. Therefore, they are useful for applications in high-temperature environments. Examples include heat-resistant tapes, electrical insulating tapes, heat-sealing tapes, plating masking tapes, and heat treatment masking tapes. Applications include, for example, protection, masking, temporary fixation, fixation during transport, and splicing of adherends in the manufacturing process of electronic and semiconductor components. Examples of adherends include, but are not limited to, metals such as stainless steel, copper, and iron, and these metals with plated or rust-proofed surfaces; glass, tempered or stain-resistant glass, ceramics such as porcelain; resins such as polytetrafluoroethylene, polyimide, epoxy resins, novolac resins, and polarizing plates; and composites formed by combining two or more of these.

[0101] The pressure-sensitive adhesive layer obtained by curing the silicone pressure-sensitive adhesive composition of the present invention is useful as an elastic pressure-sensitive adhesive member for various electronic devices or electrical devices, and is particularly useful as an electronic material, a member for a display device, or a member for a transducer (including for sensors, speakers, actuators, and generators).

[0102] Furthermore, the adhesive layer obtained by curing the silicone pressure-sensitive adhesive composition of the present invention can be suitably used for adhering and bonding silicone materials, particularly for adhering and bonding silicone rubber. There are no particular limitations on the types of adherends that can be bonded or fixed with the pressure-sensitive adhesive tape produced using the silicone pressure-sensitive adhesive composition of the present invention, but examples include silicone materials such as silicone rubber, silicone sealant, silicone potting material, silicone LIM material, and silicone varnish; silicone-coated release paper or release film; metal, plastic, wood, cloth, or paper coated with a silicone coating material, a silicone release agent, a silicone water repellent, or a paint containing silicone; and composites formed by combining two or more of these.

[0103] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following, parts represent parts by mass, and characteristic values ​​represent values ​​measured by the following test methods.

[0104] [Weight Average Molecular Weight (Mw)] In the present invention, the weight average molecular weight (Mw) is a value determined by GPC (gel permeation chromatography) analysis using polystyrene as a standard substance under the following conditions. (Measurement conditions) GPC measurement device: HLC-8320 (manufactured by Tosoh Corporation) Detector: differential refractive index detector (RI) Measurement solvent: toluene Flow rate: 0.35 mL / min GPC columns: (passed in the following order) TSKgel Guardcolumn SuperHZ-L (4.6 mm I.D. × 2 cm × 1) TSKgel SuperHZ4000 (4.6 mm I.D. × 15 cm × 1) TSKgel SuperHZ3000 (4.6 mm I.D. × 15 cm × 1) TSKgel SuperHZ2000 (4.6 mm I.D. × 15 cm × 2) (all manufactured by Tosoh Corporation) Measurement temperature: 40°C Sample injection amount: 10 μL (toluene solution with a silicone concentration of 0.5 wt%)

[0105] [Adhesive Strength] Each silicone pressure-sensitive adhesive composition was applied to a 25 μm thick, 25 mm wide polyimide film using an applicator so that the thickness of the adhesive layer after curing was 30 μm, and then heated and cured at 130°C for 1 minute to produce an adhesive tape. In accordance with JIS Z0237, the adhesive tape obtained above was attached to a stainless steel plate, and pressure-bonded by moving a 2 kg rubber-coated roller back and forth once, and left at room temperature (25°C) for approximately 20 hours. Thereafter, the edge of the adhesive tape was slightly peeled and held, and the average force (N / 25 mm) required to peel the adhesive tape from the stainless steel plate at a speed of 300 mm / min in a direction at an angle of 180° was measured using a tensile tester (Shimadzu Corporation, DSC-500 Model Tester).

[0106] [Heat resistance (adhesive residue)] An adhesive tape prepared in the same manner as for the adhesive strength described above was attached to a stainless steel plate, and pressed by moving a 2 kg rubber-coated roller back and forth once to bond the tape. The tape was left at room temperature (25°C) for approximately 20 hours, and then placed in a dryer at 250°C for 1 hour. After being removed from the dryer and allowed to cool, the tape was peeled off from the stainless steel plate. The surface of the stainless steel plate was visually observed and evaluated according to the following criteria: ○: No adhesive residue was observed (i.e., no adhesive residue was left behind) △: A small amount of adhesive residue was observed (i.e., some adhesive residue was left behind) ×: A large amount of adhesive residue was observed (i.e., a lot of adhesive residue was left behind)

[0107] [Adhesion to Substrate] Each silicone pressure-sensitive adhesive composition was applied using an applicator to a polyimide film having a thickness of 25 μm, a width of 25 mm, and a length of 200 mm, or a polyethylene terephthalate film having a thickness of 23 μm, a width of 25 mm, and a length of 200 mm, so that the thickness of the pressure-sensitive adhesive layer after curing would be 30 μm, and then heated at 130° C. for 1 minute to cure, thereby producing a pressure-sensitive adhesive tape. The obtained pressure-sensitive adhesive tapes were evaluated for substrate adhesion under the two conditions shown in (i) and (ii) below, by the method described below. (i) Immediately after preparation of the adhesive tape (ii) After being laminated to a fluorine-based release film (SS1A (Nippa Corporation)) and stored for 24 hours at a constant temperature and humidity of 60°C and 90% relative humidity. Evaluation method for substrate adhesion: A 2 mm slit was made in the center of one end of a 25 mm wide adhesive tape in the width direction, and then both ends of the adhesive tape in the length direction were gripped so that the gripping distance was 100 mm and pulled in the length direction of the tape at a pulling speed of 100 mm / min. The adhesive layer was stretched and the film substrate was torn at the slit. When the tape was further pulled in the length direction in this state, it was confirmed whether the adhesive layer lifted from the film substrate (i.e., whether "peeling" occurred). ○: No lifting of the adhesive layer was observed (i.e., no peeling) △: The adhesive layer partially lifted (i.e., partial peeling occurred) ×: The adhesive layer lifted over the entire surface (i.e., peeling occurred over the entire surface)

[0108] The following raw materials were used in the examples and comparative examples. In the following formulas, Me represents a methyl group, Vi represents a vinyl group, and Ph represents a phenyl group. The bonding order of each siloxane unit shown in parentheses is not limited to the following. In each formula below, the total number of siloxane repeating units is an average value.

[0109] (A-1) z17 = 0.4, z18 = 1.6, z19 = 4,500, z20 = 76, z21 = 5.5, alkenyl group amount: 0.0020 mol / 100 g, proportion of total number of aryl group-containing organic groups: 1.7%, viscosity at 25°C when dissolved in toluene to a concentration of 30% by mass was 19,800 mPa s (A-2). z22 = 0.2, z23 = 1.8, z24 = 4,900, z25 = 160, z26 = 6, alkenyl group amount: 0.0020 mol / 100 g, proportion of total number of aryl group-containing organic groups: 3.2%, viscosity at 25°C when dissolved in toluene to a concentration of 30% by mass was 16,700 mPa s (A-3). z27 = 0.2, z28 = 1.8, z29 = 650, z30 = 23, Amount of alkenyl groups: 0.0034 mol / 100 g, Proportion of total number of aryl group-containing organic groups: 3.4%, Viscosity at 25°C: 22,100 mPa s (A-4) z31 = 1.4, z32 = 0.6, z33 = 7,300, z34 = 900, z35 = 11.5, Amount of alkenyl groups: 0.0016 mol / 100 g Ratio of total number of aryl group-containing organic groups: 11.0% Viscosity at 25°C when dissolved in toluene to a concentration of 30% by mass was 15,100 mPa s

[0110] (A'-1) z36 = 0.2, z37 = 1.8, z38 = 4,200, z39 = 4.9, alkenyl group amount: 0.0021 mol / 100 g, no aryl group-containing organic group, viscosity at 25°C when dissolved in toluene to a concentration of 30% by mass was 22,100 mPa s (A'-2). z40 = 0.3, z41 = 1.7, z42 = 5,500, z43 = 2, alkenyl group amount: 0.0009 mol / 100 g, no aryl group-containing organic group, viscosity at 25°C when dissolved in toluene to a concentration of 30% by mass was 38,500 mPa s (A'-3) z44 = 2, z45 = 450, alkenyl group content: 0.0060 mol / 100 g, no aryl group-containing organic group, viscosity at 25°C: 5,000 mPa·s

[0111] (B-1) Me ３ SiO １／２ Units and SiO ４／２ Organopolysiloxane (Me ３ SiO １／２ Units / SiO ４／２ Unit (molar ratio) = 0.74 / 1.0), Weight average molecular weight: 3,830, Silicon atom-bonded hydroxyl group content: 0.039 mol / 100 g, Silicon atom-bonded alkoxy group content: 0.052 mol / 100 g, Total of silicon atom-bonded hydroxyl groups and alkoxy groups: 0.091 mol / 100 g (B-2) Me ３ SiO １／２ Units and SiO ４／２ Organopolysiloxane (Me ３ SiO １／２ Units / SiO ４／２ Units (molar ratio) = 0.83 / 1.0), Weight average molecular weight: 3,450, Silicon atom-bonded hydroxyl group content: 0.077 mol / 100 g, Silicon atom-bonded alkoxy group content: 0.013 mol / 100 g, Total of silicon atom-bonded hydroxyl groups and alkoxy groups: 0.090 mol / 100 g (B-3) Me ３ SiO １／２ Units and SiO ４／２ Organopolysiloxane (Me ３ SiO １／２ Units / SiO ４／２Units (molar ratio) = 0.76 / 1.0), Weight average molecular weight: 4,520, Silicon atom-bonded hydroxyl group content: 0.054 mol / 100 g, Silicon atom-bonded alkoxy group content: 0.044 mol / 100 g, Sum of silicon atom-bonded hydroxyl groups and alkoxy groups: 0.098 mol / 100 g. In the above components (B-1), (B-2), and (B-3), the alkoxy group refers to one or more alkoxy groups selected from alkoxy groups having 1 to 4 carbon atoms.

[0112] (B'-1) Me ３ SiO １／２ Units and SiO ４／２ Organopolysiloxane (Me ３ SiO １／２ Units / SiO ４／２ Units (molar ratio) = 0.68 / 1.0), Weight average molecular weight: 2,770, Silicon atom-bonded hydroxyl group content: 0.087 mol / 100 g, Silicon atom-bonded alkoxy group content: 0.060 mol / 100 g, Total of silicon atom-bonded hydroxyl groups and alkoxy groups: 0.147 mol / 100 g (B'-2) Me ３ SiO １／２ Units and SiO ４／２ Organopolysiloxane (Me ３ SiO １／２ Units / SiO ４／２ (B'-3) Me (unit (molar ratio) = 0.70 / 1.0), weight average molecular weight 7,060, silicon atom-bonded hydroxyl group content 0.033 mol / 100 g, silicon atom-bonded alkoxy group content 0.033 mol / 100 g, total of silicon atom-bonded hydroxyl groups and alkoxy groups: 0.066 mol / 100 g ３ SiO １／２ Units and SiO ４／２ Organopolysiloxane (Me ３ SiO １／２ Units / SiO ４／２Units (molar ratio) = 0.82 / 1.0), weight average molecular weight 2,250, silicon atom-bonded hydroxyl group content 0.108 mol / 100 g, silicon atom-bonded alkoxy group content 0.010 mol / 100 g, total of silicon atom-bonded hydroxyl groups and alkoxy groups: 0.118 mol / 100 g (B'-4) Me ３ SiO １／２ Units, Me ２ ViSiO １／２ and SiO ４／２ Organopolysiloxane (Me ３ SiO １／２ Units / SiO ４／２ Units (molar ratio) = 0.73 / 1.0), weight average molecular weight 2,950, silicon atom-bonded hydroxyl group content 0.027 mol / 100g, silicon atom-bonded alkoxy group content 0.038 mol / 100g, amount of alkenyl groups 0.0810 mol / 100g, total amount of silicon atom-bonded hydroxyl groups and alkoxy groups: 0.065 mol / 100g. In the above components (B'-1), (B'-2), (B'-3) and (B'-4), the alkoxy group refers to one or more alkoxy groups selected from alkoxy groups having 1 to 4 carbon atoms.

[0113] (C-1) z46 = 2, z47 = 50, Ratio of SiH groups: 47.2%, Amount of hydrogen atoms bonded to silicon atoms: 1.578 mol / 100 g (C-2) z48 = 2, z49 = 90, z50 = 10, SiH group ratio: 43.7%, aryl group ratio: 9.4%, amount of hydrogen atoms bonded to silicon atoms: 1.191 mol / 100 g

[0114] (D-1) Platinum catalyst CAT-PL-50T (manufactured by Shin-Etsu Chemical Co., Ltd.) (E-1) Ethynylcyclohexanol (F-1) Hindered phenol antioxidant IRGANOX 1330 (manufactured by BASF Japan Ltd.)

[0115] [Preparation and Property Evaluation of Silicone Pressure-Sensitive Adhesive Compositions] <Examples 1 to 11> Components (A), (A'), (B), (C), and optional components were placed in a flask according to the blending amounts shown in Tables 1 and 2 below, and 0.2 parts by mass of component (E-1) and 150 parts by mass of toluene were added and stirred to dissolve. To the resulting solution, 50 ppm (platinum mass equivalent) of component (D-1) relative to the total mass of components (A), (A'), (B), and (C) was added, followed by stirring and mixing to prepare a silicone pressure-sensitive adhesive composition. The resulting silicone pressure-sensitive adhesive composition was cured using the method described above, and its adhesive strength, substrate adhesion, and heat resistance were measured using the methods described above. The results are shown in Tables 1 and 2.

[0116] Comparative Examples 1 to 8 Components (A), (A'), (B), (B'), (C), and optional components were placed in a flask according to the blending amounts shown in Tables 3 and 4 below, and 0.2 parts by mass of component (E-1) and 150 parts by mass of toluene were added and stirred to dissolve. To the resulting solution, 50 ppm (platinum mass equivalent) of component (D-1) was added relative to the total mass of components (A), (A'), (B), (B'), and (C), and the mixture was stirred and mixed to prepare a silicone pressure-sensitive adhesive composition. The resulting silicone pressure-sensitive adhesive composition was cured using the method described above, and its adhesive strength, substrate adhesion, and heat resistance were measured using the methods described above. The results are shown in Tables 3 and 4.

[0117]

[0118]

[0119]

[0120]

[0121] As shown in Tables 3 and 4 above, the pressure-sensitive adhesive tapes obtained from the compositions of Comparative Examples 1 to 3, in which component (B') was used instead of component (B), and Comparative Examples 4 to 6, in which component (A') was used instead of component (A) all exhibited poor substrate adhesion. In the composition of Comparative Example 7, the aryl group-containing component (A) was replaced with an aryl group-free component (A'), and an organohydrogenpolysiloxane having an aryl group-containing organic group was also blended, but the substrate adhesion of the resulting pressure-sensitive adhesive tape did not improve. In the composition of Comparative Example 8, a low-viscosity, aryl-free alkenyl group-containing silicone oil (A'-3) and an alkenyl group-containing organopolysiloxane resin (B'-4) described in Patent Document 4 were used in combination, but the adhesive strength of the resulting pressure-sensitive adhesive tape was low, and the substrate adhesion after 1 day at 60°C and 90% RH was insufficient.

[0122] In contrast, the pressure-sensitive adhesive tapes obtained from the silicone pressure-sensitive adhesive compositions of the present invention have high adhesive strength, excellent substrate adhesion to polyimide films and polyethylene terephthalate films, and also good heat resistance, as shown in Tables 1 and 2. The pressure-sensitive adhesive tape obtained from the composition of Example 9, which also uses component (A') that does not contain an aryl group, and the pressure-sensitive adhesive tape obtained from the composition of Example 5, which also uses a heat-resistant additive, also maintain high adhesive strength and have excellent substrate adhesion and heat resistance.

Claims

1. A silicone pressure-sensitive adhesive composition comprising the following components (A) to (D): (A) 10 to 80 parts by mass of a linear or branched organopolysiloxane having one or more alkenyl groups and one or more aryl group-containing organic groups per molecule, the alkenyl group content being 0.0001 to 0.03 mol / 100 g, and the ratio of the total number of aryl group-containing organic groups to the total number of groups bonded to silicon atoms being 0.1 to 15%, (B) R ３ ３ SiO １／２ Units and SiO ４／２ units, (R ３ ３ SiO １／２ Unit) / (SiO ４／２ The organopolysiloxane resin (wherein R ３ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, a hydroxyl group, or an alkoxy group having 1 to 6 carbon atoms), wherein the organopolysiloxane resin has 0.001 to 0.100 mol / 100 g of hydroxyl groups bonded to silicon atoms and 0.001 to 0.100 mol / 100 g of alkoxy groups having 1 to 6 carbon atoms, the total amount of the hydroxyl groups bonded to silicon atoms and the alkoxy groups having 1 to 6 carbon atoms bonded to silicon atoms being 0.001 to 0.140 mol / 100 g, and has a weight average molecular weight of 1,000 to 6,500 in terms of standard polystyrene as measured by gel permeation chromatography (provided that the total amount of components (A) and (B) is 100 parts by mass). (C) an organohydrogenpolysiloxane having three or more silicon-bonded hydrogen atoms per molecule, in an amount such that the ratio of the total number of SiH groups in component (C) to the total number of alkenyl groups in component (A) is 0.5 to 30.0; and (D) a catalytic amount of a platinum group metal catalyst.

2. The silicone pressure-sensitive adhesive composition according to claim 1, wherein component (B) contains no alkenyl groups or contains alkenyl groups in an amount of less than 0.005 mol / 100 g.

3. The silicone pressure-sensitive adhesive composition according to claim 1, wherein component (A) is represented by the following formula (1): (In the formula, R １ are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, provided that R １ at least one of the alkenyl-containing organic groups having 2 to 10 carbon atoms and the aryl-containing organic groups having 6 to 10 carbon atoms, the alkenyl group content in the organopolysiloxane is 0.0001 to 0.03 mol / 100 g, and the group R bonded to the silicon atom １ The ratio of the total number of aryl group-containing organic groups to the total number of groups is 0.1 to 15%, and a is a positive number of 100 to 20,000.

4. The silicone pressure-sensitive adhesive composition according to claim 1, wherein component (C) is represented by the following formula (3): (In the formula, R ４ are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms and having no aliphatic unsaturated bonds; j is 0 to 1; k and m are numbers such that 1≦k≦100, 0≦m≦60, 3≦2j+k≦100, and 3≦k+m+2≦150; and a hydrogen atom bonded to a silicon atom and a group R bonded to a silicon atom ４ The ratio of the total number of hydrogen atoms bonded to silicon atoms to the total number of silicon atoms is 20 to 50%.

5. The silicone pressure-sensitive adhesive composition according to claim 1, wherein the mass ratio of said component (A) to said component (B) is 25 / 75 to 60 / 40.

6. A cured product obtained by curing the silicone pressure-sensitive adhesive composition according to any one of claims 1 to 4.

7. An adhesive tape comprising a substrate and an adhesive layer formed on at least one surface of the substrate, the adhesive layer being the cured product according to claim 6.

8. An adhesive film comprising a substrate and an adhesive layer formed on at least one surface of the substrate, the adhesive layer being the cured product according to claim 6.

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