Two-part addition curing silicone rubber composition

Abstract

To provide a two-liquid addition curing type silicone rubber composition that has good shelf stability and has a long pot life in injection molding, and a cured product thereof.SOLUTION: A two-liquid addition curing type silicone rubber composition includes (A) alkenyl group-containing organopolysiloxane, (B) organohydrogenpolysiloxane, (C) platinum-based catalyst, (D) benzotriazol and / or a benzotriazol derivative, (E-1) an acetylene alcohol compound and / or a compound modified by silane or siloxane, and (E-2) alkenyl group-containing cyclic organopolysiloxane containing a great amount of alkenyl groups different from the constituent (A) and / or alkenyl group-containing chain organopolysiloxane. The (C) and (E-2) are included in a composition X, the (B), (D), and (E-1) are included in a composition Y, and the (A) is included in at least one of the compositions X and Y. The compositions X and Y are mixed to obtain a curable, two-liquid addition curing type silicone rubber composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a two-part addition-curable silicone rubber composition. [Background technology]

[0002] Silicone rubber is used in a wide range of fields, including automotive hoses and gasket materials, electrical and electronic parts such as rolls for copying machines and packing for microwave ovens, building materials, and textile coating materials, due to its heat resistance, cold resistance, safety, electrical insulation, weather resistance, and durability. Silicone rubber can be molded by injection molding, compression molding, dispenser molding, injection molding, extrusion molding, transfer molding, etc., but injection molding using addition-curing liquid silicone rubber is the most efficient method in terms of molding cycle. Recently, molding at low temperatures and in a short time is required to further reduce the environmental load.

[0003] In order to increase the curing speed of an addition-curing liquid silicone rubber composition, it is necessary to increase the amount of catalyst or reduce the amount of control agent. However, simply increasing the amount of catalyst or reducing the amount of control agent causes a problem that the pot life is significantly shortened and workability is significantly impaired. As a method for solving this problem, a method has been proposed (Patent Document 1) in which a trace amount of a triazole-based compound is added to an addition-crosslinking silicone rubber composition, which allows fast curing at low temperatures and provides a pot life with sufficient workability.

[0004] When the addition-crosslinking silicone rubber composition containing a small amount of the above-mentioned triazole-based compound is molded in an injection molding machine, there is a sufficient pot life in the area where the two liquid components are mixed uniformly. However, in the premix section, where the mixing is not uniform and the platinum catalyst concentration is high, there is a problem that the pot life is shorter than designed.

[0005] In order to solve this problem, if an acetylene alcohol compound is mixed in advance as a reaction inhibitor with the platinum catalyst-containing component, platinum black is generated, causing the material to discolor. Also, if benzotriazole is mixed in advance as a reaction inhibitor with the platinum catalyst-containing component, the curing process slows down over time, resulting in poor storage stability. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-122271 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of the above circumstances, and has an object to provide a two-part addition-curable silicone rubber composition that has good storage stability, can be molded at a relatively low temperature in a short time, and has a long pot life even if the mixing ratio of the two parts is disrupted during injection molding. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a two-part addition curable silicone rubber composition, comprising: (A) alkenyl-containing organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass (B) Organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in each molecule: 0.2 to 20 parts by mass (C) Platinum-based catalyst: 0.5 to 500 ppm as platinum group metal (by mass) based on the total mass of the component (A) and the component (B). (D) Benzotriazole and / or benzotriazole derivative: 2 to 100 moles per mole of platinum atom in the component (C). (E-1) Acetylenic alcohol compound and / or a compound in which the alcoholic hydroxyl group of the compound is modified with silane or siloxane: 1 to 500 moles of acetylene group per mole of platinum atom of the component (C). (E-2) Alkenyl-containing cyclic organopolysiloxanes having at least one alkenyl group on every silicon atom, and / or alkenyl-containing linear organopolysiloxanes in which the proportion of alkenyl groups to the total of all substituents bonded to silicon atoms is 20 mol % or more, which are different from the component (A) described above: 1 to 500 mol per mol of platinum atoms in the component (C). and a composition X contains at least the component (C) and the component (E-2), a composition Y contains at least the component (B), the component (D) and the component (E-1), and at least one of the compositions X and Y contains the component (A), and the composition X and the composition Y can be cured by mixing them.

[0009] With such a composition, it is possible to provide a two-component addition cure type silicone rubber composition that has good storage stability, can be molded at a relatively low temperature in a short time, and has a long pot life even if the mixing ratio of the two components is disturbed during injection molding, as well as a silicone rubber cured product obtained by curing the composition.

[0010] The alkenyl group-containing cyclic organopolysiloxane in component (E-2) is represented by the following general formula (1): [ka] (wherein l is 3 or more). and / or the alkenyl group-containing linear organopolysiloxane in the component (E-2) is represented by the following general formula (2): [ka] (In the formula, R's are the same or different and are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, m is 0 or greater, n is 2 or greater, m+n is 2 or greater, and n / (m+n) is 0.2 or greater.) It is preferable that the silicone rubber composition is a two-part addition curing type silicone rubber composition represented by the formula:

[0011] By using such an organopolysiloxane, it becomes possible to control the reaction while maintaining the storage stability of the platinum catalyst.

[0012] Furthermore, it is preferable that the composition is a two-part addition curable silicone rubber composition that contains a reinforcing fine silica powder as the component (F) in an amount of 5 to 100 parts by mass per 100 parts by mass of the component (A).

[0013] The use of reinforcing fine silica powder can increase the strength of the silicone rubber composition.

[0014] The component (F) has a specific surface area of ​​50 m2 as measured by the BET method. 2 It is preferable that the fumed silica has a viscosity of 1000:1 or more.

[0015] The use of such fumed silica further improves the rubber strength.

[0016] Furthermore, the composition X and the composition Y were separately stored at 80°C for 3 days, and then uniformly mixed together to obtain a mixture. The hardening speed of the mixture was measured according to the JIS K In a vulcanization test using a torsional vibration cone die vulcanization tester described in 6300-2:2001, the composition is cured at 110°C for 5 minutes, and the degree of cure is measured. When T10 is the curing time that gives 10% of the maximum torque and T90 is the curing time that gives 90% of the maximum torque, it is preferable that the two-component addition curing silicone rubber composition has a T10 of 10 to 60 seconds and (T90 - T10) of 50 seconds or less.

[0017] Such a composition provides good workability and ease of molding.

[0018] In addition, the composition X and the composition Y were mixed uniformly, and the mixture was left to stand at 25° C. for 24 hours at a shear rate of 0.9 s -1 The viscosity at η 24 Then, η 24 It is preferable that the silicone rubber composition is a two-part addition curing type silicone rubber composition having a viscosity of ≦5000 Pa·s.

[0019] Such a silicone rubber composition is easy to mold. Effect of the Invention

[0020] According to the present invention, it is possible to provide a two-part addition cure type silicone rubber composition which has good storage stability, can be molded at a relatively low temperature in a short time, and has a long pot life even if the mixing ratio of the two parts is disturbed during injection molding, and a silicone rubber cured product obtained by curing said composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] As described above, there has been a need to provide a two-part addition cure type silicone rubber composition that has good storage stability, can be molded at a relatively low temperature in a short time, and has a long pot life even if the mixing ratio of the two parts is disturbed during injection molding, as well as a silicone rubber cured product obtained by curing such a composition.

[0022] As a result of intensive research into achieving the above-mentioned object, the present inventors have discovered that when a two-part addition curable silicone rubber composition is composed of composition X and composition Y, and the two parts are separated such that composition X contains a platinum catalyst and an alkenyl group-containing organopolysiloxane having a specific structure, and composition Y contains an organohydrogenpolysiloxane, an acetylene alcohol compound and / or a compound in which the alcoholic hydroxyl group of said compound has been modified with a silane or siloxane, benzotriazole and / or a benzotriazole derivative, it is possible to obtain a two-part addition curable silicone rubber composition which has good storage stability, can be molded at a relatively low temperature and in a short time, and has a long pot life even if the mixing ratio of the two parts is disturbed during injection molding, and a silicone rubber cured product obtained by curing said composition, which has led to the completion of the present invention.

[0023] That is, the present invention provides: A two-part addition curable silicone rubber composition, (A) alkenyl-containing organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass (B) Organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in each molecule: 0.2 to 20 parts by mass (C) Platinum-based catalyst: 0.5 to 500 ppm as platinum group metal (by mass) based on the total mass of the component (A) and the component (B). (D) Benzotriazole and / or benzotriazole derivative: 2 to 100 moles per mole of platinum atom in the component (C). (E-1) Acetylenic alcohol compound and / or a compound in which the alcoholic hydroxyl group of the compound is modified with silane or siloxane: 1 to 500 moles of acetylene group per mole of platinum atom of the component (C). (E-2) Alkenyl-containing cyclic organopolysiloxanes having at least one alkenyl group on every silicon atom, and / or alkenyl-containing linear organopolysiloxanes in which the proportion of alkenyl groups to the total of all substituents bonded to silicon atoms is 20 mol % or more, which are different from the component (A) described above: 1 to 500 mol per mol of platinum atoms in the component (C). wherein composition X contains at least the component (C) and the component (E-2), composition Y contains at least the component (B), the component (D) and the component (E-1), and at least one of composition X and Y contains component (A), and the composition can be cured by mixing composition X and composition Y.

[0024] The present invention will be described in detail below, but the present invention is not limited thereto.

[0025] [Two-part addition curable silicone rubber composition] The two-part addition-curable silicone rubber composition of the present invention comprises the following components (A), (B), (C), (D), (E-1) and (E-2).

[0026] [(A) Alkenyl-containing organopolysiloxane] Component (A) is an organopolysiloxane containing at least two alkenyl groups bonded to silicon atoms in each molecule, and is the main component (base polymer) of the composition. As component (A), those represented by the following average composition formula (3) can be used. R 1 a SiO (4-a) / 2 (3) (In the formula, R 1 are the same or different, unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, and a is a positive number from 1.5 to 2.8, preferably a positive number from 1.8 to 2.5, and more preferably a positive number from 1.95 to 2.05.

[0027] Here, R 1 Examples of the unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, and chlorine, or with cyano groups, for example, chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, and cyanoethyl. 1 90 mol % or more of R except for alkenyl groups 1 is preferably a methyl group.

[0028] Also, R 1At least two of these must be alkenyl groups (preferably having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms), and are particularly preferably vinyl groups.

[0029] The alkenyl group content in the organopolysiloxane is 1.0×10 -6 ~5.0×10 -3 mol / g, specifically 1.0×10 -5 ~2.0×10 -3 It is preferable that the alkenyl group content is 1.0×10 -6 ~5.0×10 -3 If the alkenyl group is 0.01 to 0.01 mol / g, a rubber-like substance can be obtained. The alkenyl group may be bonded to a silicon atom at the end of the molecular chain, to a silicon atom in the middle of the molecular chain, or to both.

[0030] The structure of this organopolysiloxane is basically such that both molecular chain terminals are blocked with triorganosiloxy groups and the main chain has a linear structure consisting of repeating diorganosiloxane units, but it may also have a partially branched structure, cyclic structure, etc.

[0031] Examples of the organopolysiloxane represented by the above formula (3) include dimethylpolysiloxane capped at both ends with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer capped at both ends with dimethylvinylsiloxy groups, dimethylsiloxane-diphenylsiloxane copolymer capped at both ends with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane-diphenylsiloxane copolymer capped at both ends with dimethylvinylsiloxy groups, methyltrifluoropropylpolysiloxane capped at both ends with dimethylvinylsiloxy groups, copolymer of dimethylsiloxane and methyltrifluoropropylsiloxane, copolymer of dimethylvinylsiloxane and methyltrifluoropropylsiloxane and methylvinylsiloxane both ends capped with dimethylvinylsiloxane and methyltrifluoropropylsiloxane, copolymer of dimethylsiloxane and vinylmethylsiloxane both ends capped with trimethylsiloxy groups, copolymer of dimethylsiloxane and vinylmethylsiloxane and diphenylsiloxane both ends capped with trimethylsiloxy groups, copolymer of vinylmethylsiloxane and methyltrifluoropropylsiloxane both ends capped with trimethylsiloxy groups, End-blocked dimethylpolysiloxane with trimethylsiloxy and dimethylvinylsiloxy groups, end-blocked dimethylsiloxane with trimethylsiloxy and dimethylvinylsiloxy groups, end-blocked dimethylsiloxane with trimethylsiloxy and dimethylvinylsiloxy groups, end-blocked dimethylsiloxane with diphenylsiloxane, end-blocked dimethylsiloxane with trimethylsiloxy and dimethylvinylsiloxy groups, end-blocked dimethylsiloxane with diphenylsiloxane and methylvinylsiloxane, end-blocked methyltrifluoropropylpolysiloxane with trimethylsiloxy and dimethylvinylsiloxy groups siloxane, copolymer of dimethylsiloxane and methyltrifluoropropylsiloxane terminated with terminal trimethylsiloxy groups and dimethylvinylsiloxy groups, copolymer of dimethylsiloxane and methyltrifluoropropylsiloxane and methylvinylsiloxane terminated with terminal trimethylsiloxy groups and dimethylvinylsiloxy groups, dimethylpolysiloxane terminated with methyldivinylsiloxy groups at both ends, copolymer of dimethylsiloxane and methylvinylsiloxane terminated with methyldivinylsiloxy groups at both ends, copolymer of dimethylsiloxane and diphenylsiloxane terminated with methyldivinylsiloxy groups at both ends,Dimethylsiloxane-methylvinylsiloxane-diphenylsiloxane copolymer, methyltrifluoropropylpolysiloxane, methyldivinylsiloxy-terminated dimethylsiloxane-methyltrifluoropropylsiloxane copolymer, methyldivinylsiloxy-terminated dimethylsiloxane-methyltrifluoropropylsiloxane-methylvinylsiloxane copolymer, dimethylpolysiloxane, trivinylsiloxy-terminated dimethylsiloxane, dimethylsiloxane, trivinylsiloxy-terminated dimethylsiloxane Examples of such copolymers include ethylvinylsiloxane copolymers, dimethylsiloxane-diphenylsiloxane copolymers capped at both ends with trivinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane-diphenylsiloxane copolymers capped at both ends with trivinylsiloxy groups, methyltrifluoropropylpolysiloxane capped at both ends with trivinylsiloxy groups, dimethylsiloxane-methyltrifluoropropylsiloxane copolymers capped at both ends with trivinylsiloxy groups, and dimethylsiloxane-methyltrifluoropropylsiloxane-methylvinylsiloxane copolymers capped at both ends with trivinylsiloxy groups.

[0032] Regarding the molecular weight, the average degree of polymerization (number average degree of polymerization Mn, hereinafter the same) is 1,500 or less, usually 100 to 1,500, and preferably 150 to 1,000. If the average degree of polymerization is 100 to 1,500, a rubber-like substance is obtained and the moldability is good. This average degree of polymerization can usually be determined as a polystyrene-equivalent value in GPC (gel permeation chromatography) analysis using toluene as a developing solvent.

[0033] Although there are no particular limitations on the viscosity of the organopolysiloxane of component (A), in terms of improving the handling and workability of the composition and the strength of the resulting cured product, the viscosity at 25° C. is preferably 200 to 150,000 mPa s, and more preferably 400 to 100,000 mPa s. Note that in the present invention, the viscosity is the viscosity at 25° C. measured by the method described in JIS K 7117-1:1999, and is a value measured using a BH type rotational viscometer.

[0034] As the component (A), one or more organopolysiloxanes having different molecular structures or degrees of polymerization can be used in combination, so long as they contain alkenyl groups bonded to at least two silicon atoms.

[0035] [(B) Organohydrogenpolysiloxane] Component (B) is an organohydrogenpolysiloxane having at least two, and preferably three or more, hydrogen atoms bonded to silicon atoms (SiH groups) in each molecule. The SiH groups in the molecule crosslink with the alkenyl groups bonded to silicon atoms in component (A) via a hydrosilylation addition reaction, thereby acting as a curing agent (crosslinking agent) for curing the composition.

[0036] The organohydrogenpolysiloxane of component (B) is, for example, represented by the following average composition formula (4) and has at least 2, preferably 3 or more, more preferably 3 to 100, and even more preferably 4 to 50 silicon-bonded hydrogen atoms (SiH groups) in one molecule. R 2 b H c SiO (4-b-c) / 2 (4) (In the formula, R 2 are the same or different, unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms. In addition, b is a positive number of 0.7 to 2.1, c is a positive number of 0.001 to 1.0, and b+c is a positive number satisfying 0.8 to 3.0.

[0037] Here, R 2 As the monovalent hydrocarbon group, R 1 Examples of the alkyl group include those similar to those exemplified in 1. above, but those having no aliphatic unsaturated groups are preferred.

[0038] Furthermore, b is a positive number of 0.7 to 2.1, and preferably a positive number of 0.8 to 2.0, c is a positive number of 0.001 to 1.0, and preferably a positive number of 0.01 to 1.0, and b+c is a positive number satisfying 0.8 to 3.0, and preferably a positive number satisfying 1.0 to 2.5, and the molecular structure of the organohydrogenpolysiloxane may be any of a linear, cyclic, branched, and three-dimensional network structure.

[0039] The content of SiH groups in the organohydrogenpolysiloxane is preferably 0.0005 to 0.020 mol / g, particularly preferably 0.001 to 0.017 mol / g. If the amount of SiH groups is 0.0005 mol / g or more, crosslinking proceeds sufficiently and strength can be easily obtained, while if it is 0.020 mol / g or less, a stable organohydrogenpolysiloxane can be obtained.

[0040] In this case, it is preferable to use a compound that is liquid at room temperature (25° C.) and has a number of silicon atoms (or degree of polymerization) in one molecule of 2 to 300, particularly 3 to 150, and especially about 4 to 100. The hydrogen atoms bonded to the silicon atoms may be located at either the terminals of the molecular chain or in the middle of the molecular chain (non-terminal), or may be located at both.

[0041] Examples of the organohydrogenpolysiloxane of component (B) above include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, tris(hydrogendimethylsiloxy)methylsilane, tris(hydrogendimethylsiloxy)phenylsilane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane-dimethylsiloxane cyclic copolymer, methylhydrogenpolysiloxane blocked at both ends with trimethylsiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymer blocked at both ends with trimethylsiloxy groups, dimethylpolysiloxane blocked at both ends with dimethylhydrogensiloxy groups, dimethylsiloxane blocked at both ends with dimethylhydrogensiloxy groups, and dimethylsiloxane blocked at both ends with dimethylhydrogensiloxy groups. Siloxane-methylhydrogensiloxane copolymer, methylhydrogensiloxane-diphenylsiloxane copolymer with trimethylsiloxy groups at both ends, methylhydrogensiloxane-diphenylsiloxane-dimethylsiloxane copolymer with trimethylsiloxy groups at both ends, methylhydrogensiloxane-methylphenylsiloxane-dimethylsiloxane copolymer with trimethylsiloxy groups at both ends, methylhydrogensiloxane-dimethylsiloxane-diphenylsiloxane copolymer with dimethylhydrogensiloxy groups at both ends, methylhydrogensiloxane-dimethylsiloxane-methylphenylsiloxane copolymer with dimethylhydrogensiloxy groups at both ends, (CH3)2HSiO 1 / 2 Units and (CH3)3SiO 1 / 2 Units and SiO 4 / 2 A copolymer consisting of (CH3)2HSiO units. 1 / 2 Units and SiO 4 / 2 A copolymer consisting of (CH3)2HSiO units. 1 / 2 Units and SiO 4 / 2 Units and (C6H5)SiO 3 / 2 and copolymers consisting of these exemplified compounds in which a part or all of the methyl groups have been replaced with other alkyl groups, phenyl groups, or the like.

[0042] The organohydrogenpolysiloxane of component (B) may be a polyvalent aromatic ring-containing organohydrogenpolysiloxane in which a part of the siloxane skeleton (-Si-O-Si-) constituting the molecule (usually a part of the position of the oxygen atom forming the siloxane bond) usually has a divalent to tetravalent aromatic ring-containing hydrocarbon skeleton (e.g., a phenylene skeleton, a bisphenylene skeleton, a bis(phenylene)ether skeleton, a bis(phenylene)methane skeleton, a 2,2-bis(phenylene)propane skeleton, a 2,2-bis(phenylene)hexafluoropropane skeleton, etc.) in the compounds exemplified above.

[0043] The amount of organohydrogenpolysiloxane (B) blended is 0.2 to 20 parts by mass, and preferably 0.3 to 10 parts by mass, per 100 parts by mass of the total of component (A). If it is less than 0.2 parts by mass, crosslinking does not proceed sufficiently, and a cured product with excellent hardness cannot be obtained. If it is more than 20 parts by mass, the silicone cured product may lose flexibility or become brittle.

[0044] Furthermore, the molar ratio (SiH groups / alkenyl groups) of hydrogen atoms bonded to silicon atoms in the organohydrogenpolysiloxane of component (B) to the total amount of alkenyl groups bonded to silicon atoms in components (A) and (B) (particularly in component (A)) is preferably 1.8 to 10, and particularly 2.0 to 5. When this ratio is 1.8 or more and 10 or less, good curability at low temperatures can be achieved, and the flexibility of the silicone cured product can be maintained.

[0045] [(C) Platinum-based catalyst (platinum group metal-based catalyst)] Examples of component (C) include platinum group metal catalysts such as platinum black, platinic chloride, chloroplatinic acid, reaction products of chloroplatinic acid with monohydric alcohols, complexes of chloroplatinic acid with olefins, and platinum bisacetoacetate.

[0046] The amount of the platinum group metal catalyst may be a catalytic amount, and is usually 0.5 to 500 ppm, particularly 1 to 200 ppm, of platinum group metal (by mass) relative to the total mass of components (A) and (B). If it is less than 0.5 ppm, curing does not proceed sufficiently, and if it is more than 500 ppm, the effect is not commensurate with the amount of catalyst, which is not economical. The platinum group metal catalyst of component (C) may be used alone or in combination of two or more kinds.

[0047] [(D) Benzotriazole and / or Benzotriazole Derivatives] The component (D) is benzotriazole and / or a benzotriazole derivative, and the benzotriazole derivative is represented by the following general formula (I): [ka] [In the formula, R 11 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, R 12 is a monovalent hydrocarbon having 1 to 15 carbon atoms or a group represented by the following general formula (I'). [ka] (In the formula, R 3 Ha-(CH2) a -Si(OR 4 )3, and R 4 is an alkyl group having 1 to 4 carbon atoms or SiR 5 3 units (R 5 is an alkyl group having 1 to 4 carbon atoms, and a is an integer of 1 to 6. * indicates a point of attachment. By interacting with the platinum catalyst of component (C) described above, it is possible to reduce the compression set of the cured silicone rubber and obtain a pot life sufficient for working.

[0048] Here, R 11is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, and examples of the monovalent hydrocarbon group having 1 to 6 carbon atoms include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, and cyclohexyl, as well as groups in which some or all of the hydrogen atoms have been substituted with halogen atoms such as fluorine, bromine, and chlorine, or with cyano groups, such as chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, and cyanoethyl. Of these, a hydrogen atom or a methyl group is preferred from the standpoint of synthesis.

[0049] Specific examples of the benzotriazole derivatives are shown below.

[0050] [ka] (In the formula, l is an integer of 1 to 6, and R 4 is an alkyl group or a trialkylsilyl group.

[0051] Of these, the most preferred one is shown by the following formula.

[0052] [ka]

[0053] [ka]

[0054] The amount of component (D) is 2 to 100 moles, preferably 5 to 75 moles, and more preferably 10 to 50 moles, per mole of platinum atom in component (C). When the amount is 2 to 100 moles, the curability and compression set are good, and a pot life sufficient for working is obtained. When the amount is less than 2 moles, the curing is too fast at room temperature, and when it is more than 100 moles, the curing is inhibited. The benzotriazole derivative of component (D) may be used alone or in combination of two or more kinds.

[0055] [(E-1) Acetylenic alcohol compound and / or its modified compound with silane or siloxane] Component (E-1) is an acetylene alcohol compound and / or a compound in which the alcoholic hydroxyl group of such a compound has been modified with silane or siloxane. This component (E-1) functions as a reaction inhibitor for the platinum catalyst of component (C), and the curing initiation time can be controlled by the amount added.

[0056] The acetylene alcohol compound of component (E-1) may be one in which an ethynyl group and a hydroxyl group are present in the same molecule, but it is preferable that the ethynyl group and the hydroxyl group are bonded to the same carbon atom. Specific examples include the following compounds.

[0057] [ka]

[0058] In addition, the modified compound of the alcoholic hydroxyl group of the acetylene alcohol compound with silane or siloxane is a compound in which the acetylene hydroxyl group is converted into a Si-O-C bond and bonded with the silane or siloxane. For example, the following compounds can be mentioned.

[0059] [ka] (wherein s is an integer of 0 to 50, preferably an integer of 3 to 20, and t is an integer of 1 to 50, preferably an integer of 3 to 20).

[0060] The amount of the (E-1) component is acetylene / platinum atom (Pt)=1 to 500 mol / mol, preferably 1 to 300 mol / mol, and more preferably 2 to 200 mol / mol, relative to the platinum catalyst of the (C) component. If the amount is 1 to 500 mol / mol, the curability is good and a pot life sufficient for working can be obtained. On the other hand, if the amount is less than 1 mol / mol, the curing speed becomes unstable, and if it exceeds 500 mol / mol, sufficient curing does not occur. The (E-1) component may be used alone or in combination of two or more types.

[0061] [(E-2) Organopolysiloxane containing a large amount of alkenyl groups] This component (E-2) functions as a reaction inhibitor for the platinum catalyst of component (C), and the curing start time can be controlled by the amount added. In addition, even when added to the same composition, it does not act as a catalyst poison and has good storage stability. This component (E-2) is different from component (A).

[0062] The alkenyl-containing cyclic organopolysiloxane in component (E-2) is a cyclic organopolysiloxane having at least one alkenyl group on every silicon atom, and is particularly preferably one represented by the following general formula (1): [ka] (l is 3 or more.) l is equal to or greater than 3, and preferably equal to or greater than 4. By using a structure within the above range, a sufficient pot life can be obtained even in areas where the mixture is not uniform during injection molding.

[0063] Specific examples of alkenyl-containing cyclic organopolysiloxanes include the following:

[0064] [ka]

[0065] The alkenyl group-containing linear organopolysiloxane in component (E-2) is an alkenyl group-containing linear organopolysiloxane in which the proportion of alkenyl groups to the total of all substituents bonded to silicon atoms is 20 mol % or greater and can be represented, for example, by the average composition formula (a) below, with a structure represented by general formula (2) below being particularly preferred. R c Vi d SiO (4-c-d) / 2 (a) (In the formula, R's are the same or different monovalent hydrocarbon groups having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, which do not contain unsubstituted or substituted aromatic groups. In addition, c is a positive number that satisfies 0.7 to 2.1, d is a positive number that satisfies 0.001 to 1.0, and c+d is a positive number that satisfies 0.8 to 3.0.)

[0066] [ka] (In the formula, R's are the same or different and are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, m is 0 or greater, n is 2 or greater, m+n is 2 or greater, and n / (m+n) is 0.2 or greater.)

[0067] Examples of the monovalent hydrocarbon group represented by R include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, and chlorine, or with cyano groups, such as chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, and cyanoethyl.

[0068] In the case of the above general formula (2), m is 0 or more, n is 2 or more, m+n is 2 or more, and n / (m+n) is 0.2 or more, preferably m is 0 or more, n is 4 or more, and m+n is 4 or more. The proportion of alkenyl groups relative to the total of all substituents bonded to silicon atoms is 20 to 100 mol%, preferably 30 to 100 mol%, and more preferably 40 to 100 mol%. A structure within the above range makes it possible to obtain a sufficient pot life even in areas where mixing is non-uniform during injection molding. Specific examples include the following.

[0069] [ka]

[0070] The amount of the (E-2) component is, relative to the platinum catalyst of the (C) component, (E-2) component / platinum atom (Pt)=1 to 500 mol / mol, preferably 10 to 300 mol / mol, and more preferably 20 to 200 mol / mol. If the amount is 1 to 500 mol / mol, the curability is good and sufficient pot life can be obtained even if the mixing ratio of the two liquids is disturbed during injection molding. If the amount is less than 1 mol / mol, sufficient pot life cannot be obtained if the mixing ratio of the two liquids is disturbed, and if the amount is more than 500 mol / mol, the silicone rubber cured product becomes brittle. The (E-2) component may be used alone or in combination of two or more types.

[0071] [(F) Reinforcing silica fine powder] The silicone rubber composition of the present invention preferably contains a reinforcing silica fine powder as component (F). Component (F) may be contained in composition X, composition Y, or both. There are no particular limitations on the type of silica used for the reinforcing silica fine powder of component (F), and it may be any silica that is normally used as a reinforcing agent for rubber.

[0072] The reinforcing silica fine powder may be any of those used in conventional silicone rubber compositions. 2It is preferable to use a reinforcing fine silica powder having a specific surface area of ​​50 to 400 m / g or more by the BET method. 2 / g, especially 100-350m 2 / g precipitated silica (wet silica), fumed silica (dry silica), calcined silica, etc. are preferably used, and fumed silica is particularly preferred because it improves rubber strength.

[0073] The (F) component is preferably blended in an amount of 5 to 100 parts by mass per 100 parts by mass of the (A) component, and within this range sufficient rubber strength will be obtained.

[0074] The reinforcing silica fine powder may be a silica fine powder whose surface has been hydrophobized with a surface treatment agent such as a (usually hydrolyzable) organosilicon compound, for example, chlorosilane, alkoxysilane, organosilazane, etc. In this case, the silica fine powder may be one whose surface has been hydrophobized directly with a surface treatment agent in advance in a powder state, or one whose surface has been hydrophobized by adding a surface treatment agent when kneading with silicone oil (for example, the alkenyl-containing organopolysiloxane of the above component (A)).

[0075] The surface treatment can be carried out by a known technique, for example, by placing the untreated silica fine powder and the surface treatment agent in a mechanical kneader or fluidized bed sealed at normal pressure, and mixing at room temperature or by heat treatment (heating) in the presence of an inert gas as necessary. In some cases, a catalyst (such as a hydrolysis promoter) may be used to promote the surface treatment. After kneading, the surface-treated silica fine powder can be produced by drying. The amount of the surface treatment agent to be added may be equal to or greater than the amount calculated from the coverage area of ​​the treatment agent.

[0076] Specific examples of the surface treatment agent include silazanes such as hexamethyldisilazane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, trimethylmethoxysilane, triethylmethoxysilane, vinyltris(methoxyethoxy)silane, trimethylchlorosilane, dimethyldichlorosilane, divinyldimethoxysilane, and chloropropyltrimethoxysilane, and organic silicon compounds such as polymethylsiloxane and organohydrogenpolysiloxane. The surface treatment agent is particularly preferably a silane coupling agent or a silazane. The fine silica powder of component (F) may be used alone or in combination of two or more.

[0077] [Other ingredients] In addition to the above-mentioned components, various additives can be added to the two-liquid addition curing silicone rubber composition of the present invention as necessary, for example, metal oxides such as titanium oxide, iron oxide, cerium oxide, vanadium oxide, cobalt oxide, chromium oxide, manganese oxide, and their composites, quartz powder, diatomaceous earth, calcium carbonate, magnesium carbonate, alumina, carbon, hollow glass, hollow resin, conductive inorganic powders such as gold, silver, and copper, plating powder, and other inorganic fillers, and pigments, heat resistance agents, flame retardants, plasticizers, etc. may also be added. The amount of these optional components added can be the usual amount. These components may also be mixed into composition X, composition Y, or both.

[0078] [Method for preparing two-part addition curable silicone rubber composition] The two-part addition curable silicone rubber composition of the present invention is divided into composition X and composition Y, composition X contains at least the above-mentioned components (C) and (E-2), composition Y contains at least the above-mentioned components (B), (D) and (E-1), and at least one of composition X and Y contains the above-mentioned component (A), and can be cured by mixing composition X and composition Y.

[0079] This two-part addition curable silicone rubber composition can be obtained simply by uniformly mixing the above-mentioned components (A) to (E-2) and optional components at room temperature into composition X and composition Y. However, both compositions X and Y may also be obtained by heat treating, preferably, component (F) together with the surface treatment agent and water, all or a part of component (A) in a planetary mixer or kneader at a temperature of 100 to 200°C for 1 to 4 hours, and then cooling to room temperature, followed by adding and mixing the remaining components and optional components.

[0080] When composition X and composition Y are mixed, the shear rate is 0.9 s at 25°C. -1 The viscosity at this time is preferably 50 to 5,000 Pa·s, more preferably 80 to 4,000 Pa·s, and even more preferably 100 to 3,000 Pa·s. When the viscosity is 50 Pa·s or more and 5,000 Pa·s or less, molding is easy.

[0081] In the present invention, the viscosity can be measured using a shear viscometer: HAAKE MARS40 Rheometer (manufactured by Thermo Fisher Scientific).

[0082] The two-part addition-curable silicone rubber composition of the present invention has a sufficient pot life. When composition (X) and composition (Y) are mixed uniformly and allowed to stand at 25°C for 24 hours, the composition exhibits a shear rate of 0.9 s -1 The viscosity at η 24 Then, η 24 It is preferably ≦5000 Pa·s, more preferably ≦4000 Pa·s, and even more preferably ≦3000 Pa·s. If it is 5000 Pa·s or less, molding will not become difficult even if a long time has passed since the two liquids were mixed.

[0083] [Method of molding two-part addition-curing silicone rubber composition / cured silicone rubber] The method for molding the two-component addition-curable silicone rubber composition of the present invention can be freely selected depending on the viscosity of the mixture, and any method such as cast molding, compression molding, dispenser molding, injection molding, extrusion molding, or transfer molding may be used.

[0084] The curing conditions are usually 60 to 220° C. and heating and molding within a range of 5 seconds to 1 hour.

[0085] Furthermore, the two-part addition cure type silicone rubber composition of the present invention does not lose its curability even when stored for a long period of time. Compositions X and Y were stored separately at 80°C for three days, and then the mixture was mixed uniformly. The curing speed of the mixture was 100% according to the JIS K In a vulcanization test using a torsional vibration type cone die vulcanization tester described in 6300-2:2001, when the 10% curing time and the 90% curing time when measured at 110°C for 5 minutes (i.e., the time from the start of measurement when 10% and 90% torque values ​​are given with respect to the maximum torque value in 5 minutes from the start of measurement at 110°C) are T10 and T90 (seconds), it is preferable that T10 is 10 to 60 seconds and (T90-T10) is 50 seconds or less. More preferably, T10 is 15 to 55 seconds, (T90-T10) is 45 seconds or less, and even more preferably, T10 is 20 to 50 seconds, and (T90-T10) is 40 seconds or less. If it is within the above range, the work efficiency is improved. EXAMPLES

[0086] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, parts means parts by weight.

[0087] [Preparation Example 1] 60 parts of dimethylpolysiloxane (A1) with an average degree of polymerization of 750 and both ends of the molecular chain blocked with dimethylvinylsiloxy groups, and a specific surface area of ​​300 m2 measured by the BET method 240 parts of fumed silica (F1) (Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.) having a molecular weight of 1.0 to 1.0 g / g, 8.0 parts of hexamethyldisilazane, and 2.0 parts of water were mixed at room temperature for 60 minutes, and then the temperature was raised to 150° C. and the mixture was stirred for 4 hours. Next, 30 parts of dimethylpolysiloxane (A1) was further added, mixed until uniform, and cooled to obtain silicone rubber base A.

[0088] [Example 1] The mixing ratio of composition X and composition Y described below is basically 1:1.

[0089] Preparation conditions of composition X-1 A mixture of 100 parts of silicone rubber base A, 13.08 parts of dimethylpolysiloxane (A2) whose molecular chain ends are blocked with dimethylvinylsiloxy groups and whose average degree of polymerization is 220, 2.31 parts of dimethylpolysiloxane (A3) whose molecular chain ends are blocked with trimethylsiloxy groups and whose side chains (i.e., monovalent groups or atoms bonded to silicon atoms in the diorganosiloxane units constituting the main chain; the same applies below) have an average degree of polymerization of 200 and 5 mol % of the methyl groups are vinyl groups, and 0.31 parts ( platinum For atoms, 45 mol), 0.39 parts of a toluene solution of a platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (C1) (platinum atom 1% by mass), and stirred for 30 minutes to obtain a homogeneous silicone rubber composition X-1.

[0090] Preparation conditions of composition Y-1 The silicone rubber base A was mixed with 100 parts by weight of 10.77 parts by weight of dimethylpolysiloxane (A3) having an average degree of polymerization of 200, in which both molecular terminals are blocked with trimethylsiloxy groups and in which 5 mol % of the methyl groups in the side chains (i.e., monovalent groups or atoms bonded to silicon atoms in the diorganosiloxane units constituting the main chain; the same applies below) are vinyl groups. The silicone rubber base A was mixed with 10.77 parts by weight of dimethylpolysiloxane (A3) having an average degree of polymerization of 200, in which both molecular terminals are blocked with trimethylsiloxy groups and 5 mol % of the methyl groups in the side chains (i.e., monovalent groups or atoms bonded to silicon atoms in the diorganosiloxane units constituting the main chain; the same applies below). The silicone rubber base A was mixed with 10.77 parts by weight of dimethylpolysiloxane (A3) having an average degree of polymerization of 200, in which both molecular terminals are blocked with trimethylsiloxy groups and 5 mol % of the methyl groups in the side chains (i.e., monovalent groups or atoms bonded to silicon atoms in the diorganosiloxane units constituting the main chain) are vinyl groups. The silicone rubber base A was mixed with 10.77 parts by weight of dimethylpolysiloxane (A3) having an average degree of polymerization of 200, in which both molecular terminals are blocked with trimethylsiloxy groups and 5 mol % of the methyl groups in the side chains (i.e., monovalent groups or atoms bonded to silicon atoms in the diorganosiloxane units constituting the main chain) When mixed at X:Y=1:1 Benzotriazole derivatives / platinum atom=48 mol / mol) and 0.08 parts ( When mixed at X:Y=1:1 acetylene / platinum Atom = 32 mol / mol) was added and stirred for 30 minutes to obtain a homogeneous silicone rubber composition Y-1.

[0091] [ka]

[0092] 100 parts by mass of each of the silicone rubber compositions X-1 and Y-1 were mixed, and the mixture was subjected to a shear rate of 0.9 s at 25°C initially and after 24 hours. -1 Viscosity at η0, η 24 The results are shown in Table 1. After mixing X-1 and Y-1, when component (A) was taken as 100 parts by mass, component (B) was 3.13 parts by mass, component (C) was 23 ppm in terms of platinum group metal (by mass) relative to the total mass of components (A) and (B), component (D) was 48 moles per mole of platinum atom in component (C), component (E-1-1) had 32 moles of acetylene groups per mole of platinum atom in component (C), and component (E-2) was 45 moles per mole of platinum atom in component (C).

[0093] The cure properties T10, T90, and (T90-T10) at 110°C were measured for a mixture obtained by mixing 100 parts by mass each of silicone rubber compositions X-1 and Y-1, and for a mixture obtained by storing silicone rubber compositions X-1 and Y-1 for 3 days at 80°C and then mixing 100 parts by mass each, using a rheometer MDR2000 (manufactured by Alpha Technologies). The results are shown in Table 1.

[0094] Furthermore, silicone rubber compositions X-1 and Y-1 were injection molded in a 1:1 ratio using an injection molding machine (manufactured by ARBURG, machine name: Allrounder 420C). After leaving the composition in the machine for two days, the appearance of the composition and whether molding could be resumed are shown in Table 1.

[0095] [Example 2] The silicone rubber compositions X-1 and Y-1 were mixed in a ratio of 120 and 80 parts by mass, and subjected to a shear rate of 0.9 s at 25°C initially and after 24 hours. -1 Viscosity at η0, η 24 The results are shown in Table 1. After mixing X-1 and Y-1, when component (A) was taken as 100 parts by mass, component (B) was 2.49 parts by mass, component (C) was 27 ppm in terms of platinum group metal (by mass) relative to the total mass of components (A) and (B), component (D) was 32 moles per mole of platinum atom in component (C), component (E-1-1) had 22 moles of acetylene groups per mole of platinum atom in component (C), and component (E-2) was 45 moles per mole of platinum atom in component (C).

[0096] A mixture of 120 and 80 parts by mass of silicone rubber compositions X-1 and Y-1, and a mixture of 120 and 80 parts by mass of silicone rubber compositions X-1 and Y-1 stored at 80°C for 3 days and then mixed, were used to measure the cure properties T10, T90, and (T90-T10) at 110°C using a rheometer MDR2000 (manufactured by Alpha Technologies). The results are shown in Table 1.

[0097] Furthermore, silicone rubber compositions X-1 and Y-1 were injection molded in a ratio of 3:2 using an injection molding machine (manufactured by ARBURG, machine name: Allrounder 420C). After leaving the composition in the machine for two days, the appearance of the composition and whether molding could be resumed are shown in Table 1.

[0098] [Example 3] The silicone rubber compositions X-1 and Y-1 were mixed in a ratio of 140 and 60 parts by mass, and subjected to a shear rate of 0.9 s at 25°C initially and after 24 hours. -1 Viscosity at η0, η 24 The results are shown in Table 1. After mixing X-1 and Y-1, when component (A) was taken as 100 parts by mass, component (B) was 1.86 parts by mass, component (C) was 32 ppm in terms of platinum group metal (converted by mass) relative to the total mass of components (A) and (B), component (D) had 21 moles per mole of platinum atom in component (C), component (E-1-1) had 14 moles of acetylene groups per mole of platinum atom in component (C), and component (E-2) had 45 moles per mole of platinum atom in component (C).

[0099] A mixture of 140 and 60 parts by mass of silicone rubber compositions X-1 and Y-1, and a mixture of 140 and 60 parts by mass of silicone rubber compositions X-1 and Y-1 stored at 80°C for 3 days and then mixed, were used to measure the cure properties T10, T90, and (T90-T10) at 110°C using a rheometer MDR2000 (manufactured by Alpha Technologies). The results are shown in Table 1.

[0100] Furthermore, silicone rubber compositions X-1 and Y-1 were injection molded in a ratio of 7:3 using an injection molding machine (manufactured by ARBURG, machine name: Allrounder 420C). After leaving the composition in the machine for two days, the appearance of the composition and whether molding could be resumed are shown in Table 1.

[0101] [Example 4] Preparation conditions of composition X-2 A mixture of 100 parts of silicone rubber base A, 13.08 parts of dimethylpolysiloxane (A2) whose molecular chain ends are blocked with dimethylvinylsiloxy groups and whose average degree of polymerization is 220, 2.31 parts of dimethylpolysiloxane (A3) whose molecular chain ends are blocked with trimethylsiloxy groups and whose side chains (i.e., monovalent groups or atoms bonded to silicon atoms in diorganosiloxane units constituting the main chain; the same applies below) have an average degree of polymerization of 200 and 5 mol % of the methyl groups are vinyl groups, and 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane (E-2) was used as a reaction inhibitor. 3.14 Department( platinum For atoms, 455 mol), 0.39 parts of a toluene solution of a platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (C1) (platinum atom 1% by mass), and stirred for 30 minutes to obtain a homogeneous silicone rubber composition X-2.

[0102] 100 parts by mass of each of the silicone rubber compositions X-2 and Y-1 were mixed, and the mixture was subjected to a shear rate of 0.9 s at 25°C initially and after 24 hours. -1 Viscosity at η0, η 24 The results are shown in Table 1. After mixing X-2 and Y-1, when component (A) was taken as 100 parts by mass, component (B) was 3.13 parts by mass, component (C) was 23 ppm in terms of platinum group metals (converted by mass) relative to the total mass of components (A) and (B), component (D) was 48 moles per mole of platinum atom in component (C), component (E-1-1) had 32 moles of acetylene groups per mole of platinum atom in component (C), and component (E-2) was 455 moles per mole of platinum atom in component (C).

[0103] For mixtures in which 100 parts by mass of silicone rubber compositions X-2 and Y-1 were mixed, or for mixtures in which 100 parts by mass of silicone rubber compositions X-2 and Y-1 were mixed after storing them at 80°C for 3 days, the curability T10, T90, and (T90-T10) at 110°C were measured using a rheometer MDR2000 (manufactured by Alpha Technologies). The results are shown in Table 1.

[0104] Furthermore, silicone rubber compositions X-2 and Y-1 were injection molded in a 1:1 ratio using an injection molding machine (manufactured by ARBURG, machine name: Allrounder 420C). After leaving the composition in the machine for two days, the appearance of the composition and whether molding could be resumed are shown in Table 1.

[0105] [Example 5] Preparation conditions of composition Y-2 A mixture of 100 parts of silicone rubber base A, 10.77 parts of dimethylpolysiloxane (A3) having an average degree of polymerization of 200, in which both molecular chain terminals are blocked with trimethylsiloxy groups and 5 mol % of the methyl groups in the side chains (i.e., monovalent groups or atoms bonded to silicon atoms in the diorganosiloxane units constituting the main chain; the same applies below) are vinyl groups, 5.15 parts of methylhydrogenpolysiloxane (B) (dimethylsiloxane-methylhydrogensiloxane copolymer blocked with trimethylsiloxy groups at both molecular chain terminals and having SiH groups at the side chains, degree of polymerization 64, SiH group amount 0.0113 mol / g) as a crosslinking agent, and 0.31 parts of benzotriazole derivative (D1) ( When mixed at X:Y=1:1 Benzotriazole derivatives / platinum Atoms = 48 mol / mol) was added, and the following structure (E-1-2) was added as a reaction inhibitor. 0.134 Department( When mixed at X:Y=1:1 acetylene / platinum Atom = 32 mol / mol) was added and stirred for 30 minutes to obtain a uniform silicone rubber compound Y-2.

[0106] [ka]

[0107] 100 parts by mass of each of the silicone rubber compositions X-1 and Y-2 were mixed, and the mixture was subjected to a shear rate of 0.9 s at 25°C initially and after 24 hours. -1 Viscosity at η0, η 24 The results are shown in Table 1. After mixing X-1 and Y-2, when component (A) was taken as 100 parts by mass, component (B) was 3.13 parts by mass, component (C) was 23 ppm in terms of platinum group metal (by mass) relative to the total mass of components (A) and (B), component (D) was 48 moles per mole of platinum atom in component (C), component (E-1-2) had 32 moles of acetylene groups per mole of platinum atom in component (C), and component (E-2) was 45 moles per mole of platinum atom in component (C).

[0108] The cure properties T10, T90, and (T90-T10) at 110°C were measured for a mixture obtained by mixing 100 parts by mass each of silicone rubber compositions X-1 and Y-2, and for a mixture obtained by storing 100 parts by mass each of silicone rubber compositions X-1 and Y-2 at 80°C for 3 days and then mixing them together, using a rheometer MDR2000 (manufactured by Alpha Technologies). The results are shown in Table 1.

[0109] Furthermore, silicone rubber compositions X-1 and Y-2 were injection molded in a 1:1 ratio using an injection molding machine (manufactured by ARBURG, machine name: Allrounder 420C). After leaving the composition in the machine for two days, the appearance of the composition and whether molding could be resumed are shown in Table 1.

[0110] [Comparative Example 1] Preparation conditions of composition X-3 To 100 parts of silicone rubber base A, 13.08 parts of dimethylpolysiloxane (A2) whose molecular chain terminals are blocked with dimethylvinylsiloxy groups and whose average degree of polymerization is 220, 2.31 parts of dimethylpolysiloxane (A3) whose molecular chain terminals are blocked with trimethylsiloxy groups and whose side chains (i.e., monovalent groups or atoms bonded to silicon atoms in the diorganosiloxane units constituting the main chain; the same applies hereinafter) have an average degree of polymerization of 200 and in which 5 mol % of the methyl groups are vinyl groups, and 0.39 parts of a toluene solution (C1) of a complex of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (platinum atom 1% by mass) were added and stirred for 30 minutes to obtain a uniform silicone rubber composition X-3.

[0111] Preparation conditions of composition Y-3 To 100 parts of silicone rubber base A, 10.77 parts of dimethylpolysiloxane (A3) with an average degree of polymerization of 200, in which both molecular chain terminals are blocked with trimethylsiloxy groups and 5 mol % of the methyl groups in the side chains (i.e., monovalent groups or atoms bonded to silicon atoms in the diorganosiloxane units constituting the main chain; the same applies below) are vinyl groups, 5.15 parts of methylhydrogenpolysiloxane (B) with both molecular chain terminals blocked with trimethylsiloxy groups and having SiH groups in the side chains as a crosslinking agent (dimethylsiloxane-methylhydrogensiloxane copolymer with both molecular chain terminals blocked with trimethylsiloxy groups and a degree of polymerization of 64 and an amount of SiH groups of 0.0113 mol / g) were added, and 0.08 parts ( When mixed at X:Y=1:1 Acetylene / Pt atom = 32 mol / mol) was added and stirred for 30 minutes to obtain a uniform silicone rubber compound Y-3.

[0112] 100 parts by mass of each of the silicone rubber compositions X-3 and Y-3 were mixed, and the mixture was subjected to a shear rate of 0.9 s at 25°C initially and after 24 hours. -1 Viscosity at η0, η 24 The results are shown in Table 1. After mixing X-3 and Y-3, when component (A) is taken as 100 parts by mass, component (B) is 3.13 parts by mass, component (C) is 23 ppm (by mass) of platinum group metal relative to the total mass of components (A) and (B), component (E-1-1) has 32 moles of acetylene groups per mole of platinum atoms in component (C), and components (D) and (E-2) are not included.

[0113] The cure properties T10, T90, and (T90-T10) at 110°C were measured for a mixture obtained by mixing 100 parts by mass each of silicone rubber compositions X-3 and Y-3, and for a mixture obtained by storing 100 parts by mass each of silicone rubber compositions X-3 and Y-3 at 80°C for 3 days and then mixing them together, using a rheometer MDR2000 (manufactured by Alpha Technologies). The results are shown in Table 1.

[0114] Furthermore, silicone rubber compositions X-3 and Y-3 were injection molded in a 1:1 ratio using an injection molding machine (manufactured by ARBURG, machine name: Allrounder 420C). After leaving the composition in the machine for two days, the appearance of the composition and whether molding could be resumed are recorded in Table 1.

[0115] [Comparative Example 2] 100 parts by mass of each of the silicone rubber compositions X-3 and Y-1 were mixed, and the mixture was subjected to a shear rate of 0.9 s at 25°C initially and after 24 hours. -1 Viscosity at η0, η 24 The results are shown in Table 1. After mixing X-3 and Y-1, when component (A) is taken as 100 parts by mass, component (B) is 3.13 parts by mass, component (C) is 23 ppm of platinum group metal (converted by mass) relative to the total mass of components (A) and (B), component (D) has 48 moles per mole of platinum atom in component (C), component (E-1-1) has 32 moles of acetylene groups per mole of platinum atom in component (C), and component (E-2) is not included.

[0116] The cure properties T10, T90, and (T90-T10) at 110°C were measured for a mixture obtained by mixing 100 parts by mass of each of silicone rubber compositions X-3 and Y-1, and for a mixture obtained by storing 100 parts by mass of each of silicone rubber compositions X-3 and Y-1 at 80°C for 3 days and then mixing them together, using a rheometer MDR2000 (manufactured by Alpha Technologies). The results are shown in Table 1.

[0117] Furthermore, silicone rubber compositions X-3 and Y-1 were injection molded in a 1:1 ratio using an injection molding machine (manufactured by ARBURG, machine name: Allrounder 420C). After leaving the composition in the machine for two days, the appearance of the composition and whether molding could be resumed are shown in Table 1.

[0118] [Comparative Example 3] The silicone rubber compositions X-3 and Y-1 were mixed in a ratio of 120 and 80 parts by mass, and subjected to a shear rate of 0.9 s at 25°C initially and after 24 hours. -1 Viscosity at η0, η 24 The results are shown in Table 1. After mixing X-3 and Y-1, when component (A) is taken as 100 parts by mass, component (B) is 2.49 parts by mass, component (C) is 27 ppm of platinum group metal (converted by mass) relative to the total mass of components (A) and (B), component (D) has 32 moles per mole of platinum atom in component (C), component (E-1-1) has 22 moles of acetylene groups per mole of platinum atom in component (C), and component (E-2) is not included.

[0119] A mixture of 120 and 80 parts by mass of silicone rubber compositions X-3 and Y-1, and a mixture of 120 and 80 parts by mass of silicone rubber compositions X-3 and Y-1 stored at 80°C for 3 days and then mixed, were used to measure the cure properties T10, T90, and (T90-T10) at 110°C using a rheometer MDR2000 (manufactured by Alpha Technologies). The results are shown in Table 1.

[0120] Furthermore, silicone rubber compositions X-3 and Y-1 were injection molded in a ratio of 3:2 using an injection molding machine (manufactured by ARBURG, machine name: Allrounder 420C). After leaving the composition in the machine for two days, the appearance of the composition and whether molding could be resumed are recorded in Table 1.

[0121] [Comparative Example 4] The silicone rubber compositions X-3 and Y-1 were mixed in a ratio of 140 and 60 parts by mass, and subjected to a shear rate of 0.9 s at 25°C initially and after 24 hours. -1 Viscosity at η0, η 24 The results are shown in Table 1. After mixing X-3 and Y-1, when component (A) is taken as 100 parts by mass, component (B) is 1.86 parts by mass, component (C) is 32 ppm of platinum group metal (converted by mass) relative to the total mass of components (A) and (B), component (D) has 21 moles per mole of platinum atom in component (C), component (E-1-1) has 14 moles of acetylene groups per mole of platinum atom in component (C), and component (E-2) is not included.

[0122] A mixture of silicone rubber compositions X-3 and Y-1 in a ratio of 140 and 60 parts by mass, and silicone rubber compositions X-3 and Y-1 were each stored at 80°C for 3 days. 140、60 For the mixture mixed at the ratio of parts by mass, the curability T10, T90, and (T90-T10) at 110° C. were measured using a rheometer MDR2000 (manufactured by Alpha Technologies). The results are shown in Table 1.

[0123] Furthermore, silicone rubber compositions X-3 and Y-1 were injection molded in a ratio of 7:3 using an injection molding machine (manufactured by ARBURG, machine name: Allrounder 420C). After leaving the composition in the machine for two days, the appearance of the composition and whether molding could be resumed are recorded in Table 1.

[0124] [Comparative Example 5] Preparation conditions of composition X-4 A mixture of 100 parts of silicone rubber base A, 13.08 parts of dimethylpolysiloxane (A2) whose molecular chain ends are blocked with dimethylvinylsiloxy groups and whose average degree of polymerization is 220, 2.31 parts of dimethylpolysiloxane (A3) whose molecular chain ends are blocked with trimethylsiloxy groups and whose side chains (i.e., monovalent groups or atoms bonded to silicon atoms in diorganosiloxane units constituting the main chain; the same applies hereinafter) have an average degree of polymerization of 200 and in which 5 mol % of the methyl groups are vinyl groups, and 0.31 parts of benzotriazole derivative (D1) (benzotriazole derivative / platinum Then 0.39 parts of a toluene solution of a platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (C1) (platinum atom 1% by mass) was added and stirred for 30 minutes to obtain a uniform silicone rubber composition X-4.

[0125] 100 parts by mass of each of the silicone rubber compositions X-4 and Y-3 were mixed, and the mixture was subjected to a shear rate of 0.9 s at 25°C initially and after 24 hours. -1 Viscosity at η0, η 24 The results are shown in Table 1. After mixing X-4 and Y-3, when component (A) is taken as 100 parts by mass, component (B) is 3.13 parts by mass, component (C) is 23 ppm of platinum group metal (converted by mass) relative to the total mass of components (A) and (B), component (D) has 48 moles per mole of platinum atom in component (C), component (E-1-1) has 32 moles of acetylene groups per mole of platinum atom in component (C), and component (E-2) is not included.

[0126] The cure properties T10, T90, and (T90-T10) at 110°C were measured for a mixture obtained by mixing 100 parts by mass of each of silicone rubber compositions X-4 and Y-3, and for a mixture obtained by storing 100 parts by mass of each of silicone rubber compositions X-4 and Y-3 at 80°C for 3 days and then mixing them together, using a rheometer MDR2000 (manufactured by Alpha Technologies). The results are shown in Table 1.

[0127] Silicone rubber compositions X-4 and Y-3 were injection molded in a 1:1 ratio using an injection molding machine (manufactured by ARBURG, machine name: Allrounder 420C). After leaving the composition in the machine for two days, the appearance of the composition and whether molding could be resumed are recorded in Table 1.

[0128] [Comparative Example 6] Preparation conditions of composition X-5 To 100 parts of silicone rubber base A, 13.08 parts of dimethylpolysiloxane (A2) whose molecular chain terminals are blocked with dimethylvinylsiloxy groups and whose average degree of polymerization is 220, 2.31 parts of dimethylpolysiloxane (A3) whose molecular chain terminals are blocked with trimethylsiloxy groups and whose side chains (i.e., monovalent groups or atoms bonded to silicon atoms in the diorganosiloxane units constituting the main chain; the same applies hereinafter) have an average degree of polymerization of 200 and in which 5 mol % of the methyl groups are vinyl groups, and 0.39 parts of a toluene solution (C1) of a complex of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (platinum atom 1% by mass) were added and stirred for 30 minutes to obtain a uniform silicone rubber composition X-5.

[0129] Preparation conditions of composition Y-4 A mixture of 100 parts of silicone rubber base A, 10.77 parts of dimethylpolysiloxane (A3) having an average degree of polymerization of 200, in which both molecular chain terminals are blocked with trimethylsiloxy groups and 5 mol % of the methyl groups in the side chains (i.e., monovalent groups or atoms bonded to silicon atoms in the diorganosiloxane units constituting the main chain; the same applies below) are vinyl groups, 5.15 parts of methylhydrogenpolysiloxane (B) (dimethylsiloxane-methylhydrogensiloxane copolymer blocked with trimethylsiloxy groups at both molecular chain terminals and having SiH groups at the side chains, degree of polymerization 64, SiH group amount 0.0113 mol / g) as a crosslinking agent, and 0.31 parts of benzotriazole derivative (D1) ( When mixed at X:Y=1:1 Benzotriazole derivatives / platinum atom=48 mol / mol) and 0.08 parts ( When mixed at X:Y=1:1 acetylene / platinum Atom = 32 mol / mol), 0.31 parts of 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane (E-2) ( Platinum when mixed at X:Y=1:1 For atoms, 45 mol) was added and stirred for 30 minutes to obtain a uniform silicone rubber compound Y-4.

[0130] 100 parts by mass of each of the silicone rubber compositions X-5 and Y-4 were mixed, and the mixture was subjected to a shear rate test of 0.9 s at 25°C initially and after 24 hours. -1 Viscosity at η0, η 24 The results are shown in Table 1. After mixing X-5 and Y-4, when component (A) was taken as 100 parts by mass, component (B) was 3.13 parts by mass, component (C) was 23 ppm in terms of platinum group metal (converted by mass) relative to the total mass of components (A) and (B), component (D) was 48 moles per mole of platinum atom in component (C), component (E-1-1) had 32 moles of acetylene groups per mole of platinum atom in component (C), and component (E-2) was 45 moles per mole of platinum atom in component (C).

[0131] The cure properties T10, T90, and (T90-T10) at 110°C were measured for a mixture obtained by mixing 100 parts by mass of each of silicone rubber compositions X-5 and Y-4, and for a mixture obtained by storing 100 parts by mass of each of silicone rubber compositions X-5 and Y-4 at 80°C for 3 days and then mixing them together, using a rheometer MDR2000 (manufactured by Alpha Technologies). The results are shown in Table 1.

[0132] Furthermore, silicone rubber compositions X-5 and Y-4 were injection molded in a 1:1 ratio using an injection molding machine (manufactured by ARBURG, machine name: Allrounder 420C). After leaving the composition in the machine for two days, the appearance of the composition and whether molding could be resumed are shown in Table 1.

[0133] [Comparative Example 7] Preparation conditions of composition (1) To 100 parts of silicone rubber base A, 13.08 parts of dimethylpolysiloxane (A2) whose molecular chain ends are blocked with dimethylvinylsiloxy groups and whose average polymerization degree is 220, 2.31 parts of dimethylpolysiloxane (A3) whose molecular chain ends are blocked with trimethylsiloxy groups and whose side chains (i.e., monovalent groups or atoms bonded to silicon atoms in the diorganosiloxane units constituting the main chain; the same applies below) have an average polymerization degree of 200 and 5 mol % of the methyl groups are vinyl groups, and 0.04 parts of ethynylcyclohexanol (E1-1) (acetylene / platinum Atom = 16 mol / mol), 0.39 parts of a toluene solution (C1) of a complex of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (platinum atom: 1 mass %) was added, and the mixture was stirred for 30 minutes to obtain a uniform silicone rubber composition X-6. However, the composition turned black, so the investigation was abandoned.

[0134] [Table 1]

[0135] All of the examples of the present invention have sufficiently low shear viscosity even 24 hours after mixing, and have excellent hardening performance not only when they are prepared and hardened immediately, but also when they are mixed and hardened after being left at 80°C for 3 days after preparation. In addition, when filled in an injection mold and left for 2 days, all of them are liquid, making it possible to resume molding.

[0136] On the other hand, Comparative Examples 1 to 4 and 6 hardened or had high shear viscosity 24 hours after mixing, and when filled in an injection mold and left for 2 days, they hardened or became highly viscous, making it impossible to resume molding. In Comparative Example 5, in which component (D) was added to composition X, the shear viscosity and injection molding machine evaluation were good, but the hardening performance deteriorated in a test to evaluate the storage stability when the mixture was mixed and hardened after being left at 80°C for 3 days after preparation.

[0137] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention.

Claims

1. A two-part addition curable silicone rubber composition, (A) Alkenyl-containing organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in each molecule: 100 parts by mass (B) Organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in each molecule: 0.2 to 20 parts by mass (C) Platinum-based catalyst: 0.5 to 500 ppm as platinum group metal (by mass) based on the total mass of the (A) component and the (B) component (D) Benzotriazole and / or a benzotriazole derivative represented by the following general formula (T): 2 to 100 moles per mole of platinum atom in the component (C) 【Chemistry 1】 (Wherein, l is an integer from 1 to 6, R ４ is an alkyl group having 1 to 4 carbon atoms or a SiR 5 3 group (R 5 is an alkyl group having 1 to 4 carbon atoms). (E-1) Acetylenic alcohol compound and / or a compound in which the alcoholic hydroxyl group of the compound is modified with silane or siloxane: 1 to 500 moles of acetylene group per mole of platinum atom of the component (C). (E-2) Alkenyl-containing cyclic organopolysiloxanes which have at least one alkenyl group on every silicon atom and / or alkenyl-containing linear organopolysiloxanes in which the proportion of alkenyl groups to the total of all substituents bonded to silicon atoms is 20 mol % or more, which are different from the aforementioned component (A). 1 to 500 mol of this component are contained per mol of platinum atoms in the aforementioned component (C). a two-part addition curable silicone rubber composition, which is characterized in that composition X contains at least the component (C) and the component (E-2), composition Y contains at least the component (B), the component (D) and the component (E-1), and at least one of composition X and Y contains component (A), and the composition X and composition Y can be cured by mixing them.

2. The alkenyl group-containing cyclic organopolysiloxane in the component (E-2) is represented by the following general formula (1): 【Chemistry 2】 (wherein l is 3 or more). and / or the alkenyl group-containing linear organopolysiloxane in the component (E-2) is represented by the following general formula (2): 【Chemistry 3】 (In the formula, R may be the same or different and is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, m is 0 or greater, n is 2 or greater, m+n is 2 or greater, and n / (m+n) is 0.2 or greater.) The two-part addition curable silicone rubber composition according to claim 1, characterized in that it is represented by the formula:

3. The two-part addition curable silicone rubber composition according to claim 1 or 2, further comprising a reinforcing silica fine powder as a component (F) in an amount of 5 to 100 parts by mass per 100 parts by mass of the component (A).

4. The component (F) has a specific surface area of ​​50 m as measured by the BET method. ２ 4. The two-part addition curable silicone rubber composition according to claim 3, wherein the silica is a fumed silica having a viscosity of at least 1000 MPa.

5. 5. The two-part addition curing silicone rubber composition according to claim 1, wherein the composition X and the composition Y are stored separately at 80°C for three days and then uniformly mixed together, and the curing speed of the mixture is such that, in a curing test using a torsion vibration cone die curing tester described in JIS K 6300-2:2001, the mixture is cured at 110°C for 5 minutes and the degree of curing is measured, where T10 is the curing time that gives 10% of the maximum torque and T90 is the curing time that gives 90% of the maximum torque, T10 is 10 to 60 seconds and (T90 - T10) is 50 seconds or less.

6. The composition X and the composition Y were mixed uniformly, and the mixture was left at rest for 24 hours at 25° C. and then cooled to room temperature at a shear rate of 0.9 s －１ The viscosity at η ２４ Then, η ２４ 6. The two-part addition curable silicone rubber composition according to claim 1, wherein the viscosity is ≦5000 Pa·s or less.

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