JP5032767B2 - Silicone pressure-sensitive adhesive composition and adhesive tape - Google Patents

Description

The present invention relates to a silicone-based pressure-sensitive adhesive composition characterized by having a low content of a volatile low-molecular siloxane component, and a pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer obtained by curing the composition, and having less adhesive residue Regarding tape.

Silicone-based pressure-sensitive adhesive compositions are characterized by excellent electrical insulation, heat resistance, cold resistance, and adhesion to various adherends, so heat-resistant tape, electrical insulation tape, heat seal tape, plating masking tape, etc. It is used for the purpose. These silicone-based pressure-sensitive adhesive compositions are classified into an addition reaction curable type, a condensation reaction curable type, and a peroxide curable type depending on the curing mechanism, and are cured rapidly by room temperature or heating. Are preferably used.

Examples of the addition reaction curable silicone pressure-sensitive adhesive composition include (A1) diorganopolysiloxane (viscosity 20,000 to 100,000 centipoise) in which vinyl groups are bonded to silicon atoms at both ends of the molecular chain. (B1) Organopolysiloxane resin comprising R ₃ SiO _1/2 unit (wherein R is a monovalent hydrocarbon group having 6 or less carbon atoms) and SiO _4/2 unit, (C1) silicon atom-bonded hydrogen Organopolysiloxane having atoms {1.0 to 20.0 parts of silicon-bonded hydrogen atoms in component (C1) with respect to 1.0 part of the total alkenyl groups of component (A1) and component (B1) And a silicone-based pressure-sensitive adhesive comprising a platinum-based catalyst (see Patent Document 1 below); (A2) diorganopolysiloxane having alkenyl groups bonded to silicon atoms at both ends of the molecular chain (viscosity) 00,000 centipoise or higher), (B2) R ₃ SiO _1/2 units (wherein, R is an alkyl group, an alkenyl group or a hydroxyl group,.) And an organopolysiloxane resin composed of SiO _4/2 units, (C2 ) Organopolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule {silicon in the component (C2) relative to the sum of alkenyl groups in the component (A2) and alkenyl groups in the component (B2) Amount of atomic bond hydrogen atoms from 1 to 20}, a silicone-based pressure-sensitive adhesive composition (see Patent Document 2 below) comprising (D2) a platinum-based catalyst and (E2) an organic solvent is known. Patent Document 3 discloses (A3) diorganopolysiloxane containing an alkenyl group and having a degree of polymerization of 101 to 3,001, (B3) SiO _4/2 unit and R ₃ SiO _1/2 unit (wherein R represents a monovalent hydrocarbon group or a hydroxyl group having 3 or less carbon atoms), and an organopolysiloxane resin having a molar ratio of 1: 0.6 to 1: 1.2, (C3) an organohydrogenpolysiloxane, Silicone pressure sensitive adhesive compositions characterized by (D3) platinum compounds and (E3) organic solvents are known.

However, when these silicone-based pressure-sensitive adhesive compositions are used in the field of electrical and electronic materials, the low-molecular siloxane component contained in these compositions volatilizes in the oven during thermal curing, and a large amount of In order to generate dust, it has been a factor of reducing work efficiency such as requiring considerable frequency of cleaning work. In addition, when the cured silicone-based pressure-sensitive adhesive composition containing a large amount of volatile low-molecular siloxane is brought into direct contact with an electrical / electronic product, the low-molecular siloxane remaining in the composition gradually increases. There was a serious problem of volatilizing and causing contact failure of each product.

As a curable organopolysiloxane composition in which the content of volatile low-molecular siloxane is suppressed to a very small amount, (A3) an alkenyl group having 2 to 6 carbon atoms bonded to silicon atoms at both ends of the molecular chain, at 25 ° C. An organopolysiloxane having a viscosity of 100 to 10,000 mPa · s and a low-molecular-weight siloxane component having a degree of polymerization of 20 or less, each of which is suppressed to 100 ppm, and an organo having two SiH groups in one molecule An organopolysiloxane having a chain length extended by a hydrosilylation reaction with a SiH group in the polysiloxane and having an alkenyl group at the end of the molecular chain; and (B3) an organohydrogen poly having two or more SiH groups in one molecule. Low molecular weight siloxane containing siloxane and (C3) platinum group metal catalyst and having a polymerization degree of 20 or less Each content curable organopolysiloxane composition which is suppressed to 100ppm or less minute (see Patent Document 4) is known. However, a pressure-sensitive adhesive tape having a silicone-based pressure-sensitive adhesive layer obtained by curing the composition on a support film is exposed to a high temperature for a long time in a state of being adhered to the adherend, and then attached to the adherend. After peeling off the adhesive tape, there was a problem of adhesive residue that part of the pressure-sensitive adhesive layer remained on the adherend. That is, in the solder reflow process of the electric circuit board, when using the composition according to Patent Document 3 as a masking tape for heat treatment, the pressure-sensitive adhesive layer remains on the substrate after the tape is removed after the heat treatment, There was a problem that trouble occurred in a later process.

Japanese Patent Publication No.54-37907 JP-A 63-22886 JP 2002-285129 A Japanese Patent No. 2632607

The present invention has been made to solve the above-mentioned problems, has excellent work efficiency at the time of curing, does not cause contact failure of electronic products, has high tackiness and tackiness, and is exposed to high temperatures. It is an object of the present invention to provide a silicone-based pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer characterized in that there is almost no adhesive residue, and a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer obtained by curing the composition. .

（式中、Ｒ^１は非置換もしくはハロゲン原子で置換した炭素原子数１〜１０の一価の炭化水素基、Ｒ^２は炭素原子数２〜１０のアルケニル基であり、ｎは粘度が下記範囲となるような数である。）で表わされる、２５℃における粘度が１０，５００〜６０，０００ｍＰａ・ｓであるオルガノポリシロキサンと
（ｂ）一般式（２）

（式中、Ｒ^１は炭素原子数１〜１０の非置換もしくはハロゲン原子で置換した一価の炭化水素基、ｍは１０〜２００の整数）で表される分子鎖両末端にケイ素原子結合水素原子を有するジオルガノハイドロジェンポリシロキサンを、ヒドロシリル化反応用触媒の存在下で付加反応により鎖長延長させて得た分子鎖両端にアルケニル基を有する直鎖状のオルガノポリシロキサン
（Ｂ）Ｒ_３ＳｉＯ_１／２単位とＳｉＯ_４／２単位からなるオルガノポリシロキサンレジン（式中、Ｒは炭素原子数１〜１０のアルキル基、アルケニル基、アリール基、アラルキル基またはシラノール基であり、Ｒで示される全ての基のうち、少なくとも一つはアルキル基またはアルケニル基である）
（Ｃ）一分子中に２個以上のケイ素原子結合水素原子を有するオルガノハイドロジェンポリシロキサン、および
（Ｄ）ヒドロシリル化反応用触媒
からなり、重合度２０以下の低分子オルガノポリシロキサン成分の含有量が１０００ｐｐｍ以下であることを特徴とするシリコーン系感圧接着剤組成物、および基材上に該組成物を硬化させてなる感圧接着層が形成されていることを特徴とする粘着テープによって、上記課題を解決できることを見出し、本発明に到達した。
As a result of intensive studies to achieve the above object, the present inventors
(A) (a) General formula (1)

(In the formula, R ¹ is a monovalent hydrocarbon group having 1 to 10 carbon atoms which is unsubstituted or substituted with a halogen atom , R ² is an alkenyl group having 2 to 10 carbon atoms, and n has a viscosity within the following range. And an organopolysiloxane having a viscosity at 25 ° C. of 10,500 to 60,000 mPa · s, and (b) the general formula (2)

(Wherein R ¹ is an unsubstituted or monovalent hydrocarbon group substituted with a halogen atom having 1 to 10 carbon atoms, and m is an integer of 10 to 200). Linear organopolysiloxane (B) R ₃ having an alkenyl group at both ends of a molecular chain obtained by subjecting a diorganohydrogenpolysiloxane having atoms to chain extension by addition reaction in the presence of a catalyst for hydrosilylation reaction Organopolysiloxane resin comprising SiO _1/2 units and SiO _4/2 units (wherein R is an alkyl group, alkenyl group, aryl group, aralkyl group or silanol group having 1 to 10 carbon atoms, represented by R At least one of all the groups is an alkyl group or an alkenyl group)
(C) an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms in one molecule and (D) a hydrosilylation reaction catalyst, and a content of a low-molecular organopolysiloxane component having a polymerization degree of 20 or less A pressure-sensitive adhesive layer formed by curing the composition on a base material, and a pressure-sensitive adhesive tape characterized by comprising: The present inventors have found that the above problems can be solved and have reached the present invention.

（式中、Ｒ^１は非置換もしくはハロゲン原子で置換した炭素原子数１〜１０の一価の炭化水素基、Ｒ^２は炭素原子数２〜１０のアルケニル基であり、ｎは粘度が下記範囲となるような数である。）で表わされる、２５℃における粘度が１０，５００〜６０，０００ｍＰａ・ｓであるオルガノポリシロキサンと
（ｂ）一般式（２）

（式中、Ｒ^１は炭素原子数１〜１０の非置換もしくはハロゲン原子で置換した一価の炭化水素基、ｍは１０〜２００の整数）で表される分子鎖両末端にケイ素原子結合水素原子を有するジオルガノハイドロジェンポリシロキサンを、ヒドロシリル化反応用触媒の存在下で付加反応により鎖長延長させて得た分子鎖両端にアルケニル基を有する直鎖状のオルガノポリシロキサン
（Ｂ）Ｒ_３ＳｉＯ_１／２単位とＳｉＯ_４／２単位からなるオルガノポリシロキサンレジン（式中、Ｒは炭素原子数１〜１０のアルキル基、アルケニル基、アリール基、アラルキル基またはシラノール基であり、Ｒで示される全ての基のうち、少なくとも一つはアルキル基またはアルケニル基である）
（Ｃ）一分子中に２個以上のケイ素原子結合水素原子を有するオルガノハイドロジェンポリシロキサン、および
（Ｄ）ヒドロシリル化反応用触媒
からなり、重合度２０以下の低分子オルガノポリシロキサン成分の含有量が１０００ｐｐｍ以下であることを特徴とするシリコーン系感圧接着剤組成物。
〔２〕前記の（ａ）成分中に含まれる重合度２０以下の環状または直鎖状のポリジメチルシロキサン成分のそれぞれの含有量が１００重量ｐｐｍ以下であることを特徴とする、〔１〕に記載のシリコーン系感圧接着剤組成物。
〔３〕（Ａ）成分の重量平均分子量が１００，０００〜２，０００，０００（ＧＰＣによるポリスチレン換算値）である〔１〕または〔２〕に記載のシリコーン系感圧接着剤組成物。
〔４〕（Ａ）成分が以下の平均構造式（３）で示される重量平均分子量が１００，０００〜２，０００，０００（ＧＰＣによるポリスチレン換算値）のオルガノポリシロキサンであることを特徴とする〔１〕または〔２〕に記載されたシリコーン系感圧接着剤組成物。

（式中、Ｒ^１、Ｒ^２ 、ｎ、ｍは前記と同じであり、Ｒ ^３ は炭素原子数２〜１０のアルキレン基であり、ｐは前記重量平均分子量の範囲を満たす数である）
〔５〕（Ａ）成分と（Ｂ）成分に含まれるアルケニル基 １．０モルに対して、当該（Ｃ）成分中のケイ素原子結合水素原子が１．０〜５０.０モルとなる量である、〔１〕〜〔４〕に記載のシリコーン系感圧接着剤組成物。
〔６〕基材上に、〔１〕〜〔５〕のいずれか１項に記載のシリコーン系感圧接着剤組成物の硬化による感圧接着層が形成されていることを特徴とする粘着テープ。
〔７〕前記基材がフィルム状であることを特徴とする〔６〕に記載の粘着テープ。」である。
That is, the present invention
"[1] (A) (a) General formula (1)

(In the formula, R ¹ is a monovalent hydrocarbon group having 1 to 10 carbon atoms which is unsubstituted or substituted with a halogen atom , R ² is an alkenyl group having 2 to 10 carbon atoms, and n has a viscosity within the following range. And an organopolysiloxane having a viscosity at 25 ° C. of 10,500 to 60,000 mPa · s, and (b) the general formula (2)

(Wherein R ¹ is an unsubstituted or monovalent hydrocarbon group substituted with a halogen atom having 1 to 10 carbon atoms, and m is an integer of 10 to 200). Linear organopolysiloxane (B) R ₃ having an alkenyl group at both ends of a molecular chain obtained by subjecting a diorganohydrogenpolysiloxane having atoms to chain extension by addition reaction in the presence of a catalyst for hydrosilylation reaction Organopolysiloxane resin comprising SiO _1/2 units and SiO _4/2 units (wherein R is an alkyl group, alkenyl group, aryl group, aralkyl group or silanol group having 1 to 10 carbon atoms, represented by R At least one of all the groups is an alkyl group or an alkenyl group)
(C) an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms in one molecule and (D) a hydrosilylation reaction catalyst, and a content of a low-molecular organopolysiloxane component having a polymerization degree of 20 or less Is a silicone-based pressure-sensitive adhesive composition, characterized by being 1000 ppm or less.
[2] The content of each cyclic or linear polydimethylsiloxane component having a degree of polymerization of 20 or less contained in the component (a) is 100 ppm by weight or less, in [1] The silicone-based pressure-sensitive adhesive composition described.
[3] The silicone-based pressure-sensitive adhesive composition according to [1] or [2], wherein the weight average molecular weight of the component (A) is 100,000 to 2,000,000 (polystyrene equivalent value by GPC).
[4] The component (A) is an organopolysiloxane having a weight average molecular weight of 100,000 to 2,000,000 (polystyrene equivalent value by GPC) represented by the following average structural formula (3): The silicone-based pressure-sensitive adhesive composition described in [1] or [2].

(Wherein R ¹ , R ² , n and m are the same as above , R ³ is an alkylene group having 2 to 10 carbon atoms, and p is a number satisfying the range of the weight average molecular weight)
[5] With respect to 1.0 mol of the alkenyl group contained in the components (A) and (B), the silicon-bonded hydrogen atom in the component (C) is 1.0 to 50.0 mol. The silicone-based pressure-sensitive adhesive composition according to [1] to [4].
[6] A pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer formed by curing the silicone-based pressure-sensitive adhesive composition according to any one of [1] to [5] on a substrate. .
[7] The pressure-sensitive adhesive tape according to [6], wherein the substrate is in the form of a film. Is.

According to the present invention, the content of a volatile low-molecular siloxane component is small, the work efficiency at the time of curing is excellent, it does not cause a contact failure of an electronic product, has high adhesion and tack, and has a high temperature. A silicone-based pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer characterized by almost no adhesive residue after exposure, and a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer obtained by curing the composition Can be provided.

（式中、Ｒ^１は炭素原子数１〜１０の非置換もしくはハロゲン原子で置換した一価の炭化水素基、Ｒ^２は炭素原子数２〜１０のアルケニル基であり、ｎは粘度が下記範囲となるような整数である。）で表わされる、２５℃における粘度が１０，５００〜６０，０００ｍＰａ・ｓであるオルガノポリシロキサンと、
（ｂ）一般式（２）

（式中、Ｒ^１は炭素原子数１〜１０の非置換もしくはハロゲン原子で置換した一価の炭化水素基、ｍは１０〜２００の整数）で表される分子鎖両末端にケイ素原子結合水素原子を有するオルガノハイドロジェンポリシロキサンを、ヒドロシリル化反応用触媒の存在下で付加反応により鎖長延長させて得た分子鎖両端にアルケニル基を有するオルガノポリシロキサンである。
First, the silicone-based pressure-sensitive adhesive composition of the present invention will be described in detail.
Component (A) is (a) the following general formula (1):

(In the formula, R ¹ is a monovalent hydrocarbon group unsubstituted or substituted with a halogen atom having 1 to 10 carbon atoms, R ² is an alkenyl group having 2 to 10 carbon atoms, and n has a viscosity in the following range. An organopolysiloxane having a viscosity at 25 ° C. of 10,500 to 60,000 mPa · s represented by:
(B) General formula (2)

(Wherein R ¹ is an unsubstituted or monovalent hydrocarbon group substituted with a halogen atom having 1 to 10 carbon atoms, and m is an integer of 10 to 200). It is an organopolysiloxane having an alkenyl group at both ends of a molecular chain obtained by subjecting an organohydrogenpolysiloxane having atoms to chain extension by an addition reaction in the presence of a hydrosilylation reaction catalyst.

The component (a) is an organopolysiloxane represented by the general formula (1) having alkenyl groups at both ends of the molecular chain, and the component (A) is constituted by extending the chain length by addition reaction with the component (b). To do. In the general formula (1), R ¹ is a monovalent hydrocarbon group having 1 to 10 carbon atoms that is the same or different, unsubstituted or substituted with a halogen atom , and particularly a carbon atom having no aliphatic unsaturated bond A monovalent hydrocarbon group having 1 to 10 carbon atoms is preferable, and an alkyl group having 1 to 10 carbon atoms is preferable. Specifically, R ¹ is an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, a cycloalkyl group such as a cyclohexyl group, an aryl group such as a phenyl group, a tolyl group or a xylyl group, a benzyl group, a phenylethyl group aralkyl group and groups in which a part or all substituted with a halogen atom of the hydrogen atoms of these groups, such as groups, can be, for example, chloromethyl group, a 3,3,3-trifluoropropyl group. Further, R ^2, R ² is an alkenyl group having 2 to 10 carbon atoms, specifically, vinyl group, allyl group, isopropenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, Nonenyl group and decenyl group are exemplified, and R ² is preferably vinyl group. Further, n is a number such that the viscosity of the component (a) at 25 ° C. is in the range of 10,500 to 60,000 mPa · s. Furthermore, the viscosity of the component (a) is particularly preferably in the range of 12,000 to 50,000 mPa · s, and more preferably n is in the range of 620 to 800.

式中、Ｒ^４は各々独立にケイ素原子に結合した非置換もしくは置換の１価炭化水素基であり、アルキル基、アリール基、アルケニル基、アラルキル基、水素原子、シラノール基またはアミノアルキル基が例示され、ｑは０〜１８であり、ｒは３〜２０である。２５℃における粘度が１０，５００〜６０，０００ｍＰａ・ｓのオルガノポリシロキサン中に含まれる揮発性の低分子シロキサンは、通常のストリッピングでは一定量以下の除去が困難であるが、薄膜ストリッピング装置を用いて温度２５０℃以上、圧力０．１Ｔｏｒｒ以下の条件でストリッピングを行なえば、重合度２０以下の低分子シロキサン成分のそれぞれの含有量を１００ｐｐｍ以下に抑制することができる。（ａ）成分として、２５℃における粘度が前記下限未満のオルガノポリシロキサンを付加反応により鎖長延長したオルガノポリシロキサンを用いたシリコーン系感圧接着剤組成物では、該重合度２０以下の低分子シロキサン成分のそれぞれの含有量を１００ｐｐｍ以下に抑制した場合でも、被着体に粘着した状態で長時間高温に曝した後、被着体に貼り付けた粘着テープをはがすと、感圧接着層の一部が被着体上に残るという、糊残りが発生する。また、（ａ）成分として２５℃における粘度が前記上限を超えるオルガノポリシロキサンを用いた場合、薄膜ストリッピング装置を用いた場合でも、重合度２０以下の低分子シロキサン成分のそれぞれの含有量を１００ｐｐｍ以下まで除去することは困難である。 Furthermore, the present invention is preferably characterized in that the content of each low-molecular siloxane component having a polymerization degree of 20 or less contained in the component (a) is suppressed to 100 ppm or less. By using such a component (a), it is possible to suppress the content of a low-molecular siloxane component having a polymerization degree of 20 or less in the obtained silicone-based pressure-sensitive adhesive composition to 1000 ppm or less. The low molecular siloxane component having a polymerization degree of 20 or less is exemplified by volatile linear polysiloxane or cyclic polysiloxane represented by the following general formula (4) or general formula (5).

In the formula, each R ⁴ independently represents an unsubstituted or substituted monovalent hydrocarbon group bonded to a silicon atom, and examples thereof include an alkyl group, an aryl group, an alkenyl group, an aralkyl group, a hydrogen atom, a silanol group, and an aminoalkyl group. Q is 0-18 and r is 3-20. A volatile low-molecular-weight siloxane contained in an organopolysiloxane having a viscosity at 25 ° C. of 10,500 to 60,000 mPa · s is difficult to remove below a certain amount by ordinary stripping. When stripping is performed under the conditions of a temperature of 250 ° C. or higher and a pressure of 0.1 Torr or lower, the content of each low-molecular siloxane component having a polymerization degree of 20 or less can be suppressed to 100 ppm or less. In the silicone-based pressure-sensitive adhesive composition using an organopolysiloxane in which the chain length is extended by addition reaction of an organopolysiloxane having a viscosity at 25 ° C. lower than the lower limit as component (a), the low molecular weight having a polymerization degree of 20 or less Even when each content of the siloxane component is suppressed to 100 ppm or less, after being exposed to a high temperature for a long time in a state of being adhered to the adherend, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer is removed by removing the adhesive tape attached to the adherend. Adhesive residue, that is, part remains on the adherend, occurs. Further, when an organopolysiloxane having a viscosity at 25 ° C. exceeding the above upper limit is used as the component (a), even when a thin film stripping device is used, the content of each low molecular siloxane component having a polymerization degree of 20 or less is 100 ppm. It is difficult to remove the following.

The component (b) is an organohydrogenpolysiloxane having silicon-bonded hydrogen atoms at both ends of the molecular chain, and is represented by the general formula (2). In the general formula (2), R ¹ is the same or different unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and examples thereof are the same as those described above. In particular, a monovalent hydrocarbon group having 1 to 10 carbon atoms that does not have an aliphatic unsaturated bond, particularly an alkyl group is preferred. m is an integer of 10 to 200, and m is preferably in the range of 15 to 100.

The hydrosilylation reaction catalyst for obtaining the component (A) is not particularly limited, but specifically, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefins of chloroplatinic acid. Complex, complex of chloroplatinic acid and ketones, complex of platinum and alkenylsiloxane, platinum tetrachloride, platinum fine powder, alumina or silica supported on solid platinum, platinum black, platinum olefin complex , Platinum carbonyl complexes, platinum-based catalysts of thermoplastic organic resin powders such as methyl methacrylate resins, polycarbonate resins, polystyrene resins and silicone resins containing these platinum-based catalysts; Formula: [Rh (O ₂ CCH ₃ ) ₂ ] ₂ , Rh (O ₂ CCH ₃ ) ₃ , Rh ₂ (C ₈ H ₁₅ O ₂ ) ₄ , Rh (C ₅ H ₇ O ₂ ) ₃ , Rh (C ₅ H ₇ O ₂ ) (CO) ₂ , Rh (CO ) [Ph _{3 ] (C 5 H 7 O 2} ), RhX 3 [(R 6) 2 S] 3, (R 7 3 P) 2 Rh (CO) X, (R 7 3 P) 2 Rh (CO) H, Rh 2 _{X 2 Y 4, H a Rh} b (E) c Cl d , or Rh [O (CO) R] 3 -n (OH) rhodium based catalyst (in the formula represented by _n, X is a hydrogen atom, a chlorine atom , Bromine atom, or iodine atom, Y is an alkyl group, CO, C ₈ H ₁₄ , R ⁶ is an alkyl group, a cycloalkyl group, or an aryl group, and R ⁷ is an alkyl group, an aryl group, an alkyl group, An oxy group or an aryloxy group, E is an olefin, a is 0 or 1, b is 1 or 2, c is an integer of 1 to 4, and d is 2, 3, or 4 And n is 0 or 1.); Formula: Ir (OOCCH ₃ ) ₃ , Ir (C ₅ H ₇ O ₂ ) ₃ , [Ir (Z) (E) ₂ ] ₂ , or [Ir (Z in) (Dien)] ₂ Iridium catalysts (wherein, Z is a chlorine atom, a bromine atom, an iodine atom or an alkoxy group,, E is an olefin, Dien is cyclooctadiene.) Is exemplified. It is preferable to use a chloroplatinic acid, an olefin complex of platinum, a complex of platinum and vinylsiloxane, a complex of chloroplatinic acid and divinyltetramethyldisiloxane, a complex of chloroplatinic acid and tetramethyltetravinylcyclotetrasiloxane, Platinum alkenylsiloxane complexes such as platinum divinyltetramethyldisiloxane complex and platinum tetramethyltetravinylcyclotetrasiloxane complex are particularly preferred. The addition amount of the hydrosilylation catalyst may be a catalytic amount, and is usually 1 to 1,000 ppm in terms of the amount of metal contained in the hydrosilylation catalyst with respect to the total amount of the component (a) and the component (b). Is preferably in the range of 5 to 500 ppm.

The component (A) can be obtained by subjecting the component (a) and the component (b) to an addition reaction in the presence of a hydrosilylation catalyst and extending the chain length. The order of addition of the component (a), the component (b) and the hydrosilylation catalyst is arbitrary, for example, a method of gradually adding the component (a) while heating and stirring the mixed system of the component (b) and the hydrosilylation catalyst, a) Method of gradually adding component (b) while heating and stirring the mixed system of component and hydrosilylation catalyst, and gradually adding hydrosilylation catalyst while heating and stirring the mixed system of component (a) and component (b) And a method of heating and stirring the component (a), the component (b), and the hydrosilylation catalyst mixed system. The addition reaction in the presence of such a hydrosilylation catalyst is usually performed at a temperature of 0 to 200 ° C. for 0.1 to 5 hours.

The component (A) obtained by the above method contains an alkenyl group at both ends of the molecular chain. Therefore, the ratio of the number of moles of silicon-bonded hydrogen atoms contained in component (b) / the number of moles of alkenyl groups contained in component (a) must be less than 1, and in the present invention 0.50 to It is preferably 0.95.

式中、Ｒ^１、Ｒ^２、ｎ、ｍは前記と同じであり、ｐは前記重量平均分子量の範囲を満たす１以上の数である。Ｒ^３は炭素原子数２〜１０のアルキレン基であり、具体的には、エチレン基、プロピレン基、ブタン−１，４−ジイル基、ペンタン−１，５−ジイル基、ヘキサン−１，６−ジイル基、ヘプタン−１，７−ジイル基、オクタン−１，８−ジイル基、ノナン−１，９−ジイル基が例示され、Ｒ^３として好ましくはエチレン基である。 The component (A) preferably has a weight average molecular weight (polystyrene converted value by GPC (gel permeation chromatograph)) in the range of 100,000 to 2,000,000, preferably 300,000 to 1,500,000. Those in the range of 000 are particularly preferably used from the viewpoint of adhesive performance. The component (A) is preferably an organopolysiloxane represented by the following average structural formula (3) having a weight average molecular weight within the above range.

In the formula, R ¹ , R ² , n and m are the same as described above, and p is a number of 1 or more that satisfies the range of the weight average molecular weight. R ³ is an alkylene group having 2 to 10 carbon atoms, and specifically, an ethylene group, a propylene group, a butane-1,4-diyl group, a pentane-1,5-diyl group, hexane-1,6- Examples include a diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, and a nonane-1,9-diyl group, and R ³ is preferably an ethylene group.

The component (B) is an organopolysiloxane resin composed of R ₃ SiO _1/2 units and SiO _4/2 units. In the above formula, R is an alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, an aralkyl group or a silanol group, and at least one of all groups represented by R is an alkyl group or an alkenyl group. is there. Specifically, alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group and heptyl group; cycloalkyl groups such as cyclohexyl group; alkenyl groups such as vinyl group, allyl group, butenyl group and pentenyl group Aryl groups such as phenyl group, tolyl group and xylyl group; aralkyl groups such as benzyl group and phenylethyl group, and groups in which some or all of hydrogen atoms of these groups are substituted with halogen atoms, such as 3-chloro A propyl group and a 3,3,3-trifluoropropyl group are exemplified, and a methyl group, a vinyl group, and a phenyl group are particularly preferable. The component (B) consists essentially of R ₃ SiO _1/2 units and SiO _4/2 units, but may also have R ₂ SiO _2/2 units and RSO _3/2 units. . The total content of R ₃ SiO _1/2 units and SiO _4/2 units in component (B) is preferably 50% by weight or more, more preferably 80% by weight or more, and particularly preferably 100% by weight. is there. Further, the component (B) preferably has a molar ratio of R ₃ SiO _1/2 units to SiO _4/2 units in the range of 0.5 to 1.5, more preferably 0.5 to 1. It is in the range of 0.0, particularly preferably in the range of 0.6 to 0.9. When the molar ratio of R ₃ SiO _1/2 unit to SiO _4/2 unit is less than the lower limit, the tack of the resulting silicone-based pressure-sensitive adhesive composition tends to decrease, and when the upper limit is exceeded, This is because the pressure-sensitive adhesive strength of the resulting silicone pressure-sensitive adhesive composition tends to decrease. Moreover, the compounding quantity of (B) component is 80-200 weight part with respect to 100 weight part of (A) component, Preferably it is 100-180 weight part. If it is less than the lower limit, the adhesive strength is reduced, and if it exceeds the upper limit, tack and holding force are reduced.

Component (C) is a crosslinking agent and is an organohydrogenpolysiloxane having an average of two or more silicon-bonded hydrogen atoms in one molecule. The component (C) preferably has at least three silicon-bonded hydrogen atoms in one molecule, and the bonding position is not particularly limited, but specifically, the molecular chain terminal and / or the molecular chain side chain Is mentioned. The content of silicon atom-bonded hydrogen atoms is preferably 0.1 to 2.0% by weight, more preferably 0.5 to 1.8% by weight, based on the entire composition. The organic group bonded to the silicon atom contained in the component (C) includes methyl groups, ethyl groups, propyl groups, butyl groups, pentyl groups, hexyl groups, heptyl groups and other alkyl groups; phenyl groups, tolyl groups, xylyl groups. Aryl groups such as naphthyl group; aralkyl groups such as benzyl group and phenethyl group; excluding alkenyl groups such as halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group and 3,3,3-trifluoropropyl group A substituted or unsubstituted monovalent hydrocarbon group is exemplified, and a methyl group and a phenyl group are particularly preferable, and examples of the molecular structure include linear, branched, and branched cyclic groups. It is particularly preferred that it is linear. In the case of a straight chain or branched chain, examples of the molecular chain terminal group include a trimethylsiloxy group and a dimethylhydrogensiloxy group. The viscosity of component (C) at 25 ° C. is not particularly limited, but is preferably in the range of 1 to 100,000 mPa · s, and more preferably in the range of 1 to 1,000 mPa · s.

Specifically, as the component (C), molecular chain both ends trimethylsiloxy group blocked methylhydrogenpolysiloxane, molecular chain both ends trimethylsiloxy group blocked dimethylsiloxane / methylhydrogensiloxane copolymer, molecular chain both ends trimethyl Siloxy group-blocked dimethylsiloxane / methylhydrogensiloxane / methylphenylsiloxane copolymer, dimethylhydrogensiloxy group-blocked dimethylpolysiloxane at both molecular chains, dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylphenylsiloxane copolymer at both ends of molecular chain Combined, dimethylhydrogensiloxy group-blocked methylphenylpolysiloxane at both ends of molecular chain, siloxane unit represented by formula: R ⁶ ₃ SiO _1/2 and formula: siloxane unit represented by R ⁶ ₂ HSiO _1/2 Organopolysiloxane resin composed of siloxane units represented by the formula: SiO _4/2 , Organopolysiloxane composed of siloxane units represented by the formula: R ⁶ ₂ HSiO _1/2 and siloxane units represented by the formula: SiO _4/2 Examples of the siloxane resin include siloxane units represented by the formula: R ⁶ HSiO _2/2 and siloxane units represented by the formula: R ⁶ SiO _3/2 or siloxane units represented by the formula: HSiO _3/2. It is done. These can be used alone or in combination of two or more. In the above formula, R ⁶ is a substituted or unsubstituted monovalent hydrocarbon group excluding an alkenyl group.

Component (C) is blended in an amount of 0.1 to 100 silicon-bonded hydrogen atoms in this component with respect to a total of 1 mole of alkenyl groups in component (A) and alkenyl groups in component (B). An amount that falls within the range of 0 mole, preferably an amount that falls within the range of 0.3 to 50.0 moles, and more preferably an amount that falls within the range of 1.0 to 20.0 moles. is there. Curing of the resulting silicone-based pressure-sensitive adhesive composition when the blending amount of component (C) with respect to a total of 1 mole of alkenyl groups in component (A) and alkenyl groups in component (B) is less than the lower limit. If the upper limit is exceeded and the above upper limit is exceeded, the peel resistance of the resulting pressure-sensitive adhesive to the release paper or release film increases, and this peel resistance increases with time.

Component (D) is a catalyst for hydrosilylation reaction, and the same components as those used in chain extension by the above addition reaction can be used alone or in combination of two or more. In particular, a platinum-based catalyst can be preferably used. In particular, it is preferably a platinum alkenylsiloxane complex because of its good compatibility with the component (A). Specifically, chloroplatinic acid and divinyltetramethyldisiloxane complex, chloroplatinic acid and tetramethyltetravinylcyclotetrasiloxane complex, platinum divinyltetramethyldisiloxane complex, platinum tetramethyltetravinylcyclotetrasiloxane complex Is exemplified.

The blending amount of component (D) is a catalytic amount, and is usually 1 to 1,000 ppm in terms of the amount of metal contained in component (D) with respect to the total amount of component (A), component (B), and component (C). And is preferably in the range of 5 to 500 ppm. When the blending amount of the component (D) is less than 1 ppm, the curing rate of the obtained silicone-based pressure-sensitive adhesive composition is remarkably slowed. Moreover, when the compounding quantity of (D) component exceeds 1000 ppm, problems, such as coloring, will arise in the obtained silicone type pressure sensitive adhesive composition.

In addition to the above components (A) to (D), the silicone-based pressure-sensitive adhesive composition of the present invention improves storage stability by suppressing gelation and curing at room temperature, Therefore, it is preferable to contain (E) a hydrosilylation reaction inhibitor. Examples of hydrosilylation reaction inhibitors include acetylene compounds, eneyne compounds, organic nitrogen compounds, organic phosphorus compounds, and oxime compounds. Specifically, 3-methyl-1-butyn-3-ol, 3,5-dimethyl Alkynyl alcohols such as -1-hexyn-3-ol, 3-methyl-1-penten-3-ol, and phenylbutynol; 3-methyl-3-penten-1-yne and 3,5-dimethyl-1-hexyne Examples include -3-in, benzotriazole, 1-ethynyl-1-cyclohexanol, and methylvinylcyclosiloxane. The amount of addition reaction inhibitor is usually in the range of 0.001 to 5 parts by weight per 100 parts by weight of component (A), but the type of this component, the performance and content of the hydrosilylation reaction catalyst, It may be selected appropriately according to the amount of alkenyl groups in component A) and the amount of silicon-bonded hydrogen atoms in component (C). When the addition amount of the addition reaction inhibitor exceeds 5 parts by weight with respect to 100 parts by weight of the component (A), the curing speed of the obtained silicone-based pressure-sensitive adhesive composition is remarkably slowed.

Furthermore, the silicone-based pressure-sensitive adhesive composition of the present invention contains an organic solvent for blending the component (B) into the composition as a uniform diluent or coating the composition thinly on a film-like substrate. It can be used in combination. Such an organic solvent is not particularly limited as long as it can uniformly dissolve the component (A), the component (B) and the component (C) and does not inhibit the curing by the hydrosilylation reaction. Specifically, aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as pentane, hexane and heptane; trichloroethylene, perchloroethylene, trifluoromethylbenzene, 1,3-bis (trifluoro Examples thereof include halogenated hydrocarbons such as methyl) benzene and methylpentafluorobenzene; ethyl acetate, methyl ethyl ketone, and methyl isobutyl ketone. Of these, toluene, xylene, and n-hexane are preferable from the viewpoints of solubility, safety, and economy.

The silicone-based pressure-sensitive adhesive composition of the present invention may further contain a thickener such as silica fine powder in order to increase the viscosity of the coating solution. Furthermore, known additives such as heat-resistant agents, dyes, and pigments may be further blended so long as the object and effect of the present invention are not impaired.

The silicone-based pressure-sensitive adhesive composition of the present invention can be produced by simply mixing the components (A) to (D), the component (E) and other optional components. Uniform mixing of each component is performed by mixing at a temperature of 0 to 200 ° C. using various stirrers or kneaders. The order of addition of each component is not particularly limited, but when not immediately used after mixing, the component (A), the component (B) and the component (C) are mixed with the component (D) separately. It is preferable to store them in a mixture and mix them immediately before use. Moreover, in the composition consisting of the component (A) to the component (D) and the component (E), the amount of the component (E) is adjusted so that it is not crosslinked at room temperature, and is crosslinked and cured when heated. Compositions are also preferred.

The silicone-based pressure-sensitive adhesive composition according to the present invention is applied to a substrate, and then cured by heating at room temperature or 50 to 200 ° C. under pressure to adhere to the surface of the substrate. A layer can be formed. Such a substrate is preferably a sheet-like substrate, and examples thereof include paper, cardboard paper, clay coated paper, polyolefin laminated paper, particularly polyethylene laminated paper, synthetic resin film, cloth, synthetic fiber, metal foil, and the like. The In particular, a synthetic resin film is preferable, and an unstretched or stretched synthetic resin substrate of a film on which a resin such as polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polycarbonate, polyethylene terephthalate, or nylon is formed, or these resins In particular, when heat resistance is required, polyimide, polyetheretherketone (PEEK), polyethylene naphthalate (PEN), liquid crystal polyarylate, polyamideimide (PAI), A synthetic resin film such as polyethersulfone (PES) is preferably used.

The coater for applying to the various sheet-like substrates of the silicone-based pressure-sensitive adhesive composition according to the present invention is not particularly limited, and a roll coater, a gravure coater, an air coater, a curtain flow coater, and an offset transfer roll coater are available. Illustrated.

Hereinafter, the adhesive tape according to the present invention will be described in detail.
The pressure-sensitive adhesive tape of the present invention has a base material and a silicone-based pressure-sensitive adhesive layer formed thereon by curing the silicone-based pressure-sensitive adhesive composition according to the present invention. The silicone-based pressure-sensitive adhesive composition according to the present invention is applied to a base material, preferably the sheet-like base material, by the method described above, and then heated at room temperature or 50 to 200 ° C. It can be made by curing to form a pressure-sensitive adhesive layer on the surface of the film. The coating method is exemplified by the same method as described above. When the silicone pressure sensitive adhesive is cured on the synthetic resin film, it is preferably heated, and particularly preferably heated at a temperature of 80 to 200 ° C.

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, the viscosity is a value measured at 25 ° C., and the content of low molecular siloxane in each organopolysiloxane was measured using gas chromatography (manufactured by Shimadzu Corporation, GC-14A). In the following examples, the average molecular weight is a polystyrene equivalent value measured using GPC (gel permeation chromatograph, Toso GPC-type HLC-8120). Further, the adhesive strength of the silicone-based pressure-sensitive adhesive composition, ball tack, and adhesive residue after exposure to high temperatures were measured by the following methods.
○ Adhesive strength After coating the silicone pressure-sensitive adhesive composition on a film-like support made of polyethylene terephthalate (PET) resin so that the pressure-sensitive adhesive layer after curing has a thickness of about 40 μm, A pressure-sensitive adhesive sheet was prepared by heating at 100 ° C. for 3 minutes. Next, this adhesive sheet was cut into a width of 20 mm to produce an adhesive tape. This adhesive tape was pressure-bonded to an adherend made of a stainless steel plate (SUS304) polished with No. 360 water-resistant abrasive paper using a 2 Kgf rubber roller. Then, it left still at room temperature for 30 minutes, and this adhesive force was measured by 180 degree peeling method using the constant-speed (300 mm / min) tensile tester.
○ After coating the silicone pressure-sensitive adhesive composition on a film-like support made of ball-tack polyethylene terephthalate (PET) resin so that the pressure-sensitive adhesive layer after curing has a thickness of about 40 μm, A pressure-sensitive adhesive sheet was prepared by heating at 100 ° C. for 3 minutes. Next, this pressure-sensitive adhesive sheet was placed on a slope having an angle from the horizontal direction of 40 °, and a prescribed stainless steel ball was rotated three times from above. Among the ball numbers whose rolling distance on the pressure-sensitive adhesive sheet was 10 cm or more twice or more in 3 times, the largest ball number was taken as the ball tack value.
○ After coating the pressure sensitive adhesive layer after curing the silicone pressure sensitive adhesive composition on a film-like support composed of an adhesive residue polyimide resin after exposure to high temperature so that the thickness is about 40 μm, This was heated at 100 ° C. for 3 minutes to produce an adhesive sheet. Next, this adhesive sheet was cut into a width of 20 mm to produce an adhesive tape. This adhesive tape was bonded to an adherend made of a stainless steel plate (SUS304) polished with No. 360 water-resistant abrasive paper using a 2 Kgf rubber roller. Thereafter, it is aged at 240 ° C. for 2 hours, taken out from the oven, allowed to stand at room temperature for 30 minutes, and peeled off at 180 ° using a constant-speed (300 mm / min) tensile tester against the stainless steel plate. The adhesive residue was visually confirmed. At this time, the pressure-sensitive adhesive layer does not remain on the stainless steel plate at all: ○, the pressure-sensitive adhesive layer is slightly observed on the stainless steel plate: Δ The pressure-sensitive adhesive layer remains on the stainless steel plate: × Evaluated.

[Synthesis Example 1]
100 g of a dimethylsiloxane having vinyl groups at both ends of a molecular chain in a 300 ml separable flask equipped with a thermometer and a stirrer (viscosity 13,000 mPa · s, content of low molecular siloxane having a polymerization degree of 3 to 20 is 100 ppm or less each) 100 g , HMe ₂ SiO (Me ₂ SiO) ₂₁ SiMe ₂ H 3.66 g was added, and platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex 5 ppm (platinum conversion) was added. The mixture was reacted at 25 ° C. for 4 hours with stirring to obtain a dimethylpolysiloxane (polymer (I)) having vinyl groups at both ends of a gum-like molecular chain with an average molecular weight of 500,000 and extended chain length.

[Synthesis Example 2]
100 g of a dimethylsiloxane having vinyl groups at both ends of a molecular chain in a 300 ml separable flask equipped with a thermometer and a stirrer (viscosity 35,000 mPa · s, the amount of low molecular weight siloxane having a polymerization degree of 3 to 20 is 100 ppm or less each), After adding 3.10 g of HMe ₂ SiO (Me ₂ SiO) ₂₁ SiMe ₂ H, 5 ppm (in terms of platinum amount) of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex of platinum was added, The reaction was conducted while stirring at 25 ° C. for 4 hours to obtain a dimethylpolysiloxane (polymer (b)) having an average molecular weight of 800,000 and chain-extended gum-like molecular chains having vinyl groups at both ends.

[Synthesis Example 3]
100 g of dimethylsiloxane having vinyl groups at both ends of the molecular chain in a 300 ml separable flask equipped with a thermometer and a stirrer (viscosity 13,000 mPa · s, amount of low molecular weight siloxane having a polymerization degree of 3 to 20 is 100 ppm or less) After adding 13.0 g of HMe ₂ SiO (Me ₂ SiO) ₇₀ SiMe ₂ H, 5 ppm (in terms of platinum amount) of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex of platinum was added. And a reaction with stirring at 25 ° C. for 4 hours to obtain a dimethylpolysiloxane (polymer (c)) having vinyl groups at both ends of a gum-like molecular chain with an average molecular weight of 1,000,000 and extended chain length. .

[Synthesis Example 4]
ViMe ₂ SiO (Me ₂ SiO) ₉ SiMe ₂ Vi (viscosity 5 mPa · s) 1.38 g, octamethyltetrasiloxane 643 g, and 0.68 g of siliconate containing potassium as a catalyst were added and kneaded using a kneader. Then, after cooling, carbon dioxide was added to neutralize the catalyst. Dimethylsiloxane (polymer (d)) having vinyl groups at both ends and having an average molecular weight of 500,000 was obtained.

[Synthesis Example 5]
100 g of dimethylsiloxane having vinyl groups at both ends of the molecular chain in a 300 ml separable flask equipped with a thermometer and a stirrer (viscosity 2,000 mPa · s, amount of low molecular weight siloxane having a polymerization degree of 3 to 20 is 100 ppm or less) , HMe ₂ SiO (Me ₂ SiO) ₂₁ SiMe ₂ H 6.70 g was added, and platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex 5 ppm (platinum conversion) was added. The mixture was reacted at 25 ° C. with stirring for 4 hours to obtain a dimethylpolysiloxane (polymer (e)) having vinyl groups at both ends of a gum-like molecular chain with an average molecular weight of 500,000 and extended chain length.

[Example 1]
(A) the obtained in Synthesis Example 1 Polymer (A) 25.6 parts by weight, relative to (B) (CH ₃₎ consists ₃ SiO _1/2 units and SiO _4/2 units, SiO _4/2 units ( 56.4 parts by weight of a 60% by weight xylene diluted solution of methylpolysiloxane resin having a molar ratio of CH ₃ ) ₃ SiO _1/2 units of 0.8, (C) both ends of the molecular chain having a viscosity of 20 mPa · s are trimethylsiloxy Methyl hydrogen polysiloxane blocked with a group (content of silicon atom-bonded hydrogen atom: 1.55% by weight) 0.2 part by weight, 0.2 part by weight of 2-methyl-3-butyn-2-ol, toluene 17 After mixing 6 parts by weight using a stirrer, (D) platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex of platinum is the above polymer (A) And weight unit for the total amount of methylpolysiloxane resin In was added in an amount such that 100 ppm, the organopolysiloxane component were prepared silicone-based pressure-sensitive adhesive composition is 40% by weight. The silicon-bonded hydrogen atom contained in the component (C) with respect to 1.0 mol of the vinyl group contained in the component (A) was 20.0 mol. Next, a pressure-sensitive adhesive tape was prepared using this silicone-based pressure-sensitive adhesive, and the adhesive strength, ball tack and adhesive residue were evaluated by the above-described methods. The results are shown in Table 1. Table 1 shows the total content of low molecular weight siloxanes having a degree of polymerization of 3 to 20 contained in the adhesive composition.

[Example 2]
(A) 25.6 parts by weight of the polymer (b) obtained in Synthesis Example 2 above, (B) (CH ₃ ) ₃ composed of SiO _1/2 units and SiO _4/2 units, with respect to SiO _4/2 units ( 56.4 parts by weight of a 60% by weight xylene diluted solution of methylpolysiloxane resin having a molar ratio of CH ₃ ) ₃ SiO _1/2 units of 0.8, (C) both ends of the molecular chain having a viscosity of 20 mPa · s are trimethylsiloxy Methyl hydrogen polysiloxane blocked with a group (content of silicon atom-bonded hydrogen atom: 1.55% by weight) 0.2 part by weight, 0.2 part by weight of 2-methyl-3-butyn-2-ol, toluene 17 .6 parts by weight are mixed using a stirrer, and (D) platinum metal in the complex of platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex is the above polymer (b) And weight unit for the total amount of methylpolysiloxane resin In was added in an amount such that 100 ppm, the organopolysiloxane component were prepared silicone-based pressure-sensitive adhesive composition is 40% by weight. The silicon-bonded hydrogen atom contained in the component (C) with respect to 1.0 mol of the vinyl group contained in the component (A) was 12.5 mol. Next, a pressure-sensitive adhesive tape was prepared using this silicone-based pressure-sensitive adhesive, and the adhesive strength, ball tack and adhesive residue were evaluated by the above-described methods. The results are shown in Table 1. Table 1 shows the total content of low molecular weight siloxanes having a degree of polymerization of 3 to 20 contained in the adhesive composition.

[Example 3]
(A) the polymer (C) 25.6 parts by weight obtained in Synthesis Example 3, with respect to (B) (CH ₃₎ consists ₃ SiO _1/2 units and SiO _4/2 units, SiO _4/2 units ( 56.4 parts by weight of a 60% by weight xylene diluted solution of methylpolysiloxane resin having a molar ratio of CH ₃ ) ₃ SiO _1/2 units of 0.8, (C) both ends of the molecular chain having a viscosity of 20 mPa · s are trimethylsiloxy Methyl hydrogen polysiloxane blocked with a group (content of silicon atom-bonded hydrogen atom: 1.55% by weight) 0.2 part by weight, 0.2 part by weight of 2-methyl-3-butyn-2-ol, toluene 17 .6 parts by weight are mixed using a stirrer, and (D) platinum metal in the complex of platinum, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex is the above polymer (c) And weight unit for the total amount of methylpolysiloxane resin In was added in an amount such that 100 ppm, the organopolysiloxane component were prepared silicone-based pressure-sensitive adhesive composition is 40% by weight. The silicon-bonded hydrogen atom contained in the component (C) with respect to 1.0 mol of the vinyl group contained in the component (A) was 10.0 mol. Next, a pressure-sensitive adhesive tape was prepared using this silicone-based pressure-sensitive adhesive, and the adhesive strength, ball tack and adhesive residue were evaluated by the above-described methods. The results are shown in Table 1. Table 1 shows the total content of low molecular weight siloxanes having a degree of polymerization of 3 to 20 contained in the adhesive composition.

[Comparative Example 1]
(A) 25.6 parts by weight of the polymer (d) obtained in Synthesis Example 4 above, (B) (CH ₃ ) ₃ composed of SiO _1/2 units and SiO _4/2 units, with respect to SiO _4/2 units ( 56.4 parts by weight of a 60% by weight xylene diluted solution of methylpolysiloxane resin having a molar ratio of CH ₃ ) ₃ SiO _1/2 units of 0.8, (C) both ends of the molecular chain having a viscosity of 20 mPa · s are trimethylsiloxy Methyl hydrogen polysiloxane blocked with a group (content of silicon atom-bonded hydrogen atom: 1.55% by weight) 0.2 part by weight, 0.2 part by weight of 2-methyl-3-butyn-2-ol, toluene 17 After mixing 6 parts by weight with a stirrer, (D) platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex of platinum is the above polymer (d) And weight unit for the total amount of methylpolysiloxane resin In was added in an amount such that 100 ppm, the organopolysiloxane component were prepared silicone-based pressure-sensitive adhesive composition is 40% by weight. The silicon-bonded hydrogen atom contained in the component (C) with respect to 1.0 mol of the vinyl group contained in the component (A) was 20.0 mol. Next, a pressure-sensitive adhesive tape was prepared using this silicone-based pressure-sensitive adhesive, and the adhesive strength, ball tack and adhesive residue were evaluated by the above-described methods. The results are shown in Table 1. Table 1 shows the total content of low molecular weight siloxanes having a degree of polymerization of 3 to 20 contained in the adhesive composition.

[Comparative Example 2]
(A) 25.6 parts by weight of the polymer (e) obtained in Synthesis Example 5 above, (B) (CH ₃ ) ₃ composed of SiO _1/2 units and SiO _4/2 units, with respect to SiO _4/2 units ( 56.4 parts by weight of a 60% by weight xylene diluted solution of methylpolysiloxane resin having a molar ratio of CH ₃ ) ₃ SiO _1/2 units of 0.8, (C) both ends of the molecular chain having a viscosity of 20 mPa · s are trimethylsiloxy Methyl hydrogen polysiloxane blocked with a group (content of silicon atom-bonded hydrogen atom: 1.55% by weight) 0.2 part by weight, 0.2 part by weight of 2-methyl-3-butyn-2-ol, toluene 17 After 6 parts by weight of the mixture is mixed using a stirrer, (D) platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex is complexed with the above polymer (e) And weight unit for the total amount of methylpolysiloxane resin In was added in an amount such that 100 ppm, the organopolysiloxane component were prepared silicone-based pressure-sensitive adhesive composition is 40% by weight. The silicon-bonded hydrogen atom contained in the component (C) with respect to 1.0 mol of the vinyl group contained in the component (A) was 20.0 mol. Next, a pressure-sensitive adhesive tape was prepared using this silicone-based pressure-sensitive adhesive, and the adhesive strength, ball tack and adhesive residue were evaluated by the above-described methods. The results are shown in Table 1. Table 1 shows the total content of low molecular weight siloxanes having a degree of polymerization of 3 to 20 contained in the adhesive composition.

Claims (7)

(A) (a) General formula (1)

(In the formula, R ¹ is a monovalent hydrocarbon group having 1 to 10 carbon atoms which is unsubstituted or substituted with a halogen atom , R ² is an alkenyl group having 2 to 10 carbon atoms, and n has a viscosity within the following range. And an organopolysiloxane having a viscosity at 25 ° C. of 10,500 to 60,000 mPa · s, and (b) the general formula (2)

(Wherein R ¹ is an unsubstituted or monovalent hydrocarbon group substituted with a halogen atom having 1 to 10 carbon atoms, and m is an integer of 10 to 200). Linear organopolysiloxane (B) R ₃ having an alkenyl group at both ends of a molecular chain obtained by subjecting a diorganohydrogenpolysiloxane having atoms to chain extension by addition reaction in the presence of a catalyst for hydrosilylation reaction Organopolysiloxane resin comprising SiO _1/2 units and SiO _4/2 units (wherein R is an alkyl group, alkenyl group, aryl group, aralkyl group or silanol group having 1 to 10 carbon atoms, represented by R At least one of all the groups is an alkyl group or an alkenyl group)
(C) an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms in one molecule and (D) a hydrosilylation reaction catalyst, and a content of a low-molecular organopolysiloxane component having a polymerization degree of 20 or less Is a silicone-based pressure-sensitive adhesive composition, characterized by being 1000 ppm or less. The silicone according to claim 1, wherein the content of each of the cyclic or linear polydimethylsiloxane components having a polymerization degree of 20 or less contained in the component (a) is 100 ppm by weight or less. Pressure sensitive adhesive composition. The silicone-based pressure-sensitive adhesive composition according to claim 1 or 2, wherein the component (A) has a weight average molecular weight of 100,000 to 2,000,000 (polystyrene equivalent value by GPC). The component (A) is an organopolysiloxane having a weight average molecular weight of 100,000 to 2,000,000 (polystyrene equivalent value by GPC) represented by the following average structural formula (3): Or the silicone type pressure sensitive adhesive composition of Claim 2.

(Wherein R ¹ , R ² , n and m are the same as above , R ³ is an alkylene group having 2 to 10 carbon atoms, and p is a number satisfying the range of the weight average molecular weight) The amount of silicon atom-bonded hydrogen atoms in the component (C) is 1.0 to 50.0 mol per 1.0 mol of the alkenyl group contained in the component (A) and the component (B), Item 5. The silicone-based pressure-sensitive adhesive composition according to item 1 to item 4. A pressure-sensitive adhesive tape, wherein a pressure-sensitive adhesive layer is formed on a substrate by curing the silicone-based pressure-sensitive adhesive composition according to any one of claims 1 to 5. The pressure-sensitive adhesive tape according to claim 6, wherein the substrate is in a sheet form.