TWO-PACK ADDITION-CURABLE SILICONE RUBBER COMPOSITION

Abstract

A two-pack addition-curable silicone rubber composition, containing: (A) an alkenyl-group-containing organopolysiloxane; (B) an organohydrogenpolysiloxane; (C) a platinum-based catalyst; (D) benzotriazole and/or a benzotriazole derivative; (E-1) an acetylene alcohol compound and/or a compound modified with silane or siloxane; and (E-2) an alkenyl-group-containing cyclic organopolysiloxane and/or an alkenyl-group-containing chain organopolysiloxane that has a large amount of alkenyl groups and differs from the component (A), wherein a composition X contains the components (C) and (E-2), a composition Y contains the components (B), (D), and (E-1), at least one of the compositions X or Y contains the component (A), and the two-pack addition-curable silicone rubber composition is curable by mixing the composition X and the composition Y.

Claims

1-6. (canceled)

7. A two-pack addition-curable silicone rubber composition, comprising: (A) 100 parts by mass of an alkenyl-group-containing organopolysiloxane having at least two alkenyl groups bonded to a silicon atom in one molecule; (B) 0.2 to 20 parts by mass of an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to a silicon atom in one molecule; (C) 0.5 to 500 ppm, as a platinum group metal, of a platinum-based catalyst relative to a total mass of the components (A) and (B) based on mass; (D) 2 to 100 moles of benzotriazole and/or a benzotriazole derivative relative to 1 mole of the platinum atom of the component (C); (E-1) an acetylene alcohol compound and/or a compound in which an alcoholic hydroxy group of the acetylene alcohol compound is modified with silane or siloxane at 1 to 500 moles of an acetylene group relative to 1 mole of the platinum atom of the component (C); and (E-2) an alkenyl-group-containing cyclic organopolysiloxane having at least one alkenyl group on every silicon atom thereof and/or an alkenyl-group-containing chain organopolysiloxane in which a proportion of alkenyl groups to total substituents bonded to a silicon atom is 20 mol % or more, the organopolysiloxanes differing from the component (A), at 1 to 500 moles relative to 1 mole of the platinum atom of the component (C), wherein a composition X contains at least the components (C) and (E-2), a composition Y contains at least the components (B), (D), and (E-1), at least one of the compositions X or Y contains the component (A), and the two-pack addition-curable silicone rubber composition is curable by mixing the composition X and the composition Y.

8. The two-pack addition-curable silicone rubber composition according to claim 7, wherein the alkenyl-group-containing cyclic organopolysiloxane in the component (E-2) is represented by the following general formula (1), ##STR00015## wherein 1 represents 3 or more, and/or the alkenyl-group-containing chain organopolysiloxane in the component (E-2) is represented by the following general formula (2), ##STR00016## wherein R represents a non-substituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, R being same as or different from each other, m represents 0 or more, n represents 2 or more, m+n represents 2 or more, and n/(m+n) represents 0.2 or more.

9. The two-pack addition-curable silicone rubber composition according to claim 7, further comprising 5 to 100 parts by mass of a reinforcing silica fine powder as a component (F) relative to 100 parts by mass of the component (A).

10. The two-pack addition-curable silicone rubber composition according to claim 8, further comprising 5 to 100 parts by mass of a reinforcing silica fine powder as a component (F) relative to 100 parts by mass of the component (A).

11. The two-pack addition-curable silicone rubber composition according to claim 9, wherein the component (F) is a fumed silica having a specific surface area with a BET method of 50 m.sup.2/g or more.

12. The two-pack addition-curable silicone rubber composition according to claim 10, wherein the component (F) is a fumed silica having a specific surface area with a BET method of 50 m.sup.2/g or more.

13. The two-pack addition-curable silicone rubber composition according to claim 7, wherein where T10 is defined as a curing time yielding 10% torque of a maximum torque, the maximum torque obtained from curing at 110° C. for 5 minutes followed by measuring a degree of curing in a curing test using a torsion oscillating corn-die curemeter in accordance with JIS K 6300-2:2001, and T90 is defined as a curing time yielding 90% torque of the maximum torque, a curing rate of a mixture in which the composition X and the composition Y are each separately stored at 80° C. for 3 days and then uniformly mixed has T10 of 10 to 60 seconds and (T90-T10) of 50 seconds or shorter.

14. The two-pack addition-curable silicone rubber composition according to claim 8, wherein where T10 is defined as a curing time yielding 10% torque of a maximum torque, the maximum torque obtained from curing at 110° C. for 5 minutes followed by measuring a degree of curing in a curing test using a torsion oscillating corn-die curemeter in accordance with JIS K 6300-2:2001, and T90 is defined as a curing time yielding 90% torque of the maximum torque, a curing rate of a mixture in which the composition X and the composition Y are each separately stored at 80° C. for 3 days and then uniformly mixed has T10 of 10 to 60 seconds and (T90-T10) of 50 seconds or shorter.

15. The two-pack addition-curable silicone rubber composition according to claim 9, wherein where T10 is defined as a curing time yielding 10% torque of a maximum torque, the maximum torque obtained from curing at 110° C. for 5 minutes followed by measuring a degree of curing in a curing test using a torsion oscillating corn-die curemeter in accordance with JIS K 6300-2:2001, and T90 is defined as a curing time yielding 90% torque of the maximum torque, a curing rate of a mixture in which the composition X and the composition Y are each separately stored at 80° C. for 3 days and then uniformly mixed has T10 of 10 to 60 seconds and (T90-T10) of 50 seconds or shorter.

16. The two-pack addition-curable silicone rubber composition according to claim 10, wherein where T10 is defined as a curing time yielding 10% torque of a maximum torque, the maximum torque obtained from curing at 110° C. for 5 minutes followed by measuring a degree of curing in a curing test using a torsion oscillating corn-die curemeter in accordance with JIS K 6300-2:2001, and T90 is defined as a curing time yielding 90% torque of the maximum torque, a curing rate of a mixture in which the composition X and the composition Y are each separately stored at 80° C. for 3 days and then uniformly mixed has T10 of 10 to 60 seconds and (T90-T10) of 50 seconds or shorter.

17. The two-pack addition-curable silicone rubber composition according to claim 11, wherein where T10 is defined as a curing time yielding 10% torque of a maximum torque, the maximum torque obtained from curing at 110 ° C. for 5 minutes followed by measuring a degree of curing in a curing test using a torsion oscillating corn-die curemeter in accordance with JIS K 6300-2:2001, and T90 is defined as a curing time yielding 90% torque of the maximum torque, a curing rate of a mixture in which the composition X and the composition Y are each separately stored at 80° C. for 3 days and then uniformly mixed has T10 of 10 to 60 seconds and (T90-T10) of 50 seconds or shorter.

18. The two-pack addition-curable silicone rubber composition according to claim 12, wherein where T10 is defined as a curing time yielding 10% torque of a maximum torque, the maximum torque obtained from curing at 110° C. for 5 minutes followed by measuring a degree of curing in a curing test using a torsion oscillating corn-die curemeter in accordance with JIS K 6300-2:2001, and T90 is defined as a curing time yielding 90% torque of the maximum torque, a curing rate of a mixture in which the composition X and the composition Y are each separately stored at 80° C. for 3 days and then uniformly mixed has T10 of 10 to 60 seconds and (T90-T10) of 50 seconds or shorter.

19. The two-pack addition-curable silicone rubber composition according to claim 7, wherein η.sub.24≤5000 Pa.Math.s or less where η.sub.24 is a viscosity at a shearing rate of 0.9 s.sup.−1 of an uniform mixture of the composition X and the composition Y after still standing at 25° C. for 24 hours.

20. The two-pack addition-curable silicone rubber composition according to claim 8, wherein η.sub.24≤5000 Pa.Math.s or less where η.sub.24 is a viscosity at a shearing rate of 0.9 s.sup.−1 of an uniform mixture of the composition X and the composition Y after still standing at 25° C. for 24 hours.

21. The two-pack addition-curable silicone rubber composition according to claim 9, wherein η.sub.24≤5000 Pa.Math.s or less where η.sub.24 is a viscosity at a shearing rate of 0.9 s.sup.−1 of an uniform mixture of the composition X and the composition Y after still standing at 25° C. for 24 hours.

22. The two-pack addition-curable silicone rubber composition according to claim 10, wherein η.sub.24≤5000 Pa.Math.s or less where η.sub.24 is a viscosity at a shearing rate of 0.9 s.sup.−1 of an uniform mixture of the composition X and the composition Y after still standing at 25° C. for 24 hours.

23. The two-pack addition-curable silicone rubber composition according to claim 11, wherein η.sub.24≤5000 Pa.Math.s or less where η.sub.24 is a viscosity at a shearing rate of 0.9 s.sup.−1 of an uniform mixture of the composition X and the composition Y after still standing at 25° C. for 24 hours.

24. The two-pack addition-curable silicone rubber composition according to claim 12, wherein η.sub.24≤5000 Pa.Math.s or less where η.sub.24 is a viscosity at a shearing rate of 0.9 s.sup.−1 of an uniform mixture of the composition X and the composition Y after still standing at 25° C. for 24 hours.

25. The two-pack addition-curable silicone rubber composition according to claim 13, wherein η.sub.24≤5000 Pa.Math.s or less where η.sub.24 is a viscosity at a shearing rate of 0.9 s.sup.−1 of an uniform mixture of the composition X and the composition Y after still standing at 25° C. for 24 hours.

26. The two-pack addition-curable silicone rubber composition according to claim 14, wherein η.sub.24≤5000 Pa.Math.s or less where η.sub.24 is a viscosity at a shearing rate of 0.9 s.sup.−1 of an uniform mixture of the composition X and the composition Y after still standing at 25° C. for 24 hours.

Description

EXAMPLE

[0108] Hereinafter, the present invention will be described specifically with Examples and Comparative Examples, but the present invention is not limited to the following Examples. Note that “parts” in the following examples indicates “parts by mass”.

Preparation Example

[0109] Mixing of 60 parts of a dimethylpolysiloxane (A1) blocked at both terminals of the molecular chain with dimethylvinylsiloxy groups and having an average polymerization degree of 750, 40 parts of a fumed silica (F1) (manufactured by NIPPON AEROSIL CO., LTD., AEROSIL 300) having a specific surface area with the BET method of 300 m.sup.2/g, 8.0 parts of hexamethyldisilazane, and 2.0 parts of water was performed at a room temperature for 60 minutes. Then, the mixture was heated to 150° C. and stirred for 4 hours. Thereafter, 30 parts or the dimethylpolysiloxane (A1) was further added to be mixed until the mixture became uniform, and then the mixture was cooled to obtain a silicone rubber base A.

Example 1

[0110] A mixing ratio between a composition X and composition described below, is basically 1:1.

Preparation Condition of Composition X-1

[0111] Into 100 parts of the silicone rubber base A, 13.08 parts of a dimethylpolysiloxane (A2) blocked at both terminals of the molecular chain with dimethylvinylsiloxy groups and having an average polymerization degree of 220, 2.31 parts of a dimethylpolysiloxane (A3) blocked at both terminals of the molecular chain with trimethylsiloxy groups and 5 mol % of methyl groups in side chains (that monovalent groups or atoms bonded to a silicon atom in a diorganosiloxane unit constituting the main chain, the same applies hereinafter) were substituted with vinyl groups and having an average polymerization degree of 200, 0.31 parts (91 moles relative to Pt atom) of 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane (E-2) as a reaction inhibitor, and 0.39 parts of a toluene solution (C-1) of a complex of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (1 mass % of platinum atom) were added. The mixture was stirred for 30 minutes to obtain a uniform silicone rubber composition X-1.

Preparation Condition of Composition Y-1

[0112] Into 100 parts of the silicone rubber base A, 10.77 parts of a dimethylpolysiloxane (A3) blocked at both terminals of the molecular chain with trimethylsiloxy groups and 5 mol % of methyl groups in side chains (that monovalent groups or atoms bonded to a silicon atom in a diorganosiloxane unit constituting the main chain, the same applies hereinafter) were substituted with vinyl groups and having an average polymerization degree of 200, 5.15 parts of a methylhydrogenpolysiloxane (B) blocked at both terminals of the molecular chain with trimethylsiloxy groups and having SiH groups on the side chain (dimethylsiloxane-methylhydrogensiloxane copolymer blocked at both terminals of the molecular chain with. trimethylsiloxy groups, polymerization degree: 64, SiH group amount: 0.0113 mol/g) as a crosslinker, and 0.31 parts of a beozotriazole derivative (D1) represented by the following formula (5) (benzotriazole derivative/Pt atom=48 mol/mol) were added, and 0.08 parts of ethynylcyclohexanol (E-1-1) (acetylene/Pt atom=38 mol/mol) as a reaction inhibitor was added, and the mixture was stirred for 30 minutes to obtain a uniform. silicone rubber composition Y-1.

##STR00013##

[0113] The silicone rubber compositions X-1 and Y-1 were mixed at each 100 parts by mass to measure viscosities at 25° C. and at a shearing rate of 0.9 s.sup.−1. The viscosities, η.sub.0 and η.sub.24, were an viscosity and a viscosity after 24 hours, respectively. Table 1 shows the results.

[0114] Pre-oared were the mixture in which. the silicone rubber compositions X-1 and Y-1 were mixed at each 100 parts by mass, and a mixture in which each of the silicone rubber compositions X-1 and 1-1 was separately stored under a condition at 80° C. for 3 days and then mixed at each 100 parts by mass. As the curability at 110° C., T10, T90, and (T90-T10) were measured with Rheometer MDR2000 (manufactured by Alpha Technologies Inc.). Table 1 shows the results.

[0115] Furthermore, the silicone rubber compositions X-1 and Y-1 were injection-molded at a ratio of 1:1 with an injection molding machine (manufactured by ARBURG GmbH, product name: Alirounder 420C), Table 1 shows an appearance of the composition and availability of restarting the molding after leaving the composition in the machine for 2 days.

Example 2

[0116] The silicone rubber compositions X-1 and Y-1 were mixed at a ratio of 120 and 80 parts by mass to measure viscosities at 25° C. and at a shearing rate of 0.9 The viscosities, η.sub.0 and η.sub.24, were an initial viscosity and a viscosity after 24 hours, respectively. Table 1 shows the results.

[0117] Prepared were the mixture in which the silicone rubber compositions X-1 and Y-1 were mixed at a ratio of 120 and 80 parts by mass, and a mixture in which each of the silicone rubber compositions X-1 and Y-1 was separately stored under a condition at 80° C. for 3 days and then mixed at a ratio of 120 and 80 parts by mass. As the curability at 110° C., T10, T90, and (T90-T10) were measured with Rheometer MOR2000 (manufactured by Alpha Technologies Inc.). Table 1 shows the results.

[0118] Furthermore, the silicone rubber compositions X-1 and Y-1 were injection-molded at a ratio of 3:2 with an injection molding machine (manufactured by ARBURG GmbH, product name: Alirounder 420C). Table 1 shows an appearance of the composition and availability of restarting the molding after leaving the composition in the machine for 2 days.

Example 3

[0119] The silicone rubber compositions X-1 and Y-1 were mixed at a ratio of 140 and 60 parts by mass to measure viscosities at 25° C. and at a shearing rate of 0.9 s.sup.−1. The viscosities, η.sub.0 and η.sub.24, were an initial viscosity and a viscosity after 24 hours, respectively. Table 1 shows the results.

[0120] Prepared were the mixture in which. the silicone rubber compositions X-1 and Y-1 were mixed at a ratio of 140 and 60 parts by mass, and a mixture in which each of the silicone rubber compositions X-1 and Y-1 was separately stored under a condition at 80° C. for 3 days and then mixed at a ratio of 140 and 60 parts by mass. As the curability at 110° C., T10, T90, and. (T90-T10) were measured with Rheometer MDR2000 (manufactured by Alpha Technologies inc.). Table 1 shows the results.

[0121] Furthermore, the silicone rubber compositions X-1 and Y-1 were injection-molded at a ratio of 7:3 with an injection molding machine (manufactured APEURG GmbH, product name: Allrounder 420C). Table 1 shows an appearance of the composition and availability of restarting the molding after leaving the composition in the machine for 2 days.

Example 4

Preparation Condition of Composition X-2

[0122] Into 100 parts of the silicone rubber base A, 13.08 parts of a dimethylpolysiloxane (A2) blocked at both terminals of the molecular chain with dimethylvinylsiloxy groups and having an average polymerization degree of 220, 2.31 parts of a dimethylpolysiloxane (A3) blocked at both terminals of the molecular chain with trimethyisiloxy groups and 5 mol % of methyl groups in side chains (that is, monovalent groups or atoms bonded to a silicon atom in a diorganosiloxane unit constituting the main chain, the same applies hereinafter) were substituted with vinyl groups and having an average polymerization degree of 200, 1.54 parts (456 moles relative to Pt atom) of 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane (E-2) as a reaction inhibitor, and 0.39 parts of a toluene solution (C-1) of a complex of platinum and 1,3-divinyl-3,3-tetramethyldisiloxane (1 mass % of platinum atom) were added. The mixture was stirred for 30 minutes to obtain a uniform silicone rubber composition X-2.

[0123] The silicone rubber compositions X-2 and Y-1 were mixed at each 100 parts by mass to measure viscosities at 25° C. and at a shearing rate of 0.9 s.sup.—1. The viscosities, η.sub.0 and η.sub.24, were an initial viscosity and a viscosity after 24 hours, respectively. Table 1 shows the results.

[0124] Prepared were the mixture in which the silicone rubber compositions X-2 and Y-1 were mixed at each 100 parts by mass, or a mixture in which each of the Silicone rubber compositions X-2 and Y-1 was separately stored under a condition at 80° C. for 3 days and then mixed at each. 100 parts by mass. As the curability at 110° C., T10, T90, and (T90-T10) were measured with Rheometer MER2000 (manufactured by Alpha Technologies Inc.). Table 1 shows the results.

[0125] Furthermore, the silicone rubber compositions X-2 and Y-1 were injection-molded at a ratio of 1:1 with an injection molding machine (manufactured by ARBURG GmbH, product name: Allrounder 420C). Table 1 shows an appearance of the composition and availability of restarting the molding after leaving the composition in the machine for 2 days.

Example 5

Preparation Condition of Composition Y-2

[0126] Into 100 parts of the silicone rubber base A, 10.77 parts of a dimethylpolysiloxane (A3) blocked at both terminals of the molecular chain with trimethylsiloxy groups and 5 mol % of methyl groups in side chains (that is, monovalent groups or atoms bonded to a silicon atom in a diorganosiloxane unit constituting the main chain, the same applies hereinafter) were substituted with vinyl groups and having an average polymerization degree of 200, 5.15 parts of a methylhydxogenpolysiloxane (B) blocked at both terminals of the molecular chain with trimethylsiloxy groups and having SiH groups on the side chain (dimethylsiloxane-methylhydrogensiloxane copolymer blocked at both terminals of the main chain with trimethyliloxy groups, polymerization degree: 64, SiH group amount: 0.0113 mol/g) as a crosslinker, and 0.31 parts of the benzotriazole derivative (D1) (benzotriazole derivative/Pt atom=48 mol/mol) were added, and 0.08 parts of a compound having the following structure (E-1-2) (acetylene/Pt atom=38 mol/mol) as a reaction inhibitor was added, and the mixture was stirred for 30 minutes to obtain a uniform silicone rubber blend Y-2.

##STR00014##

[0127] The silicone rubber compositions X-1 and Y-2 were mixed at each 100 parts by mass to measure viscosities at 25° C. and at a shearing rate of 0.9 s.sup.−1. The viscosities, η.sub.0 and η.sub.24, were an initial viscosity and a viscosity after 24 hours, respectively. Table 1 shows the results.

[0128] Prepared were the mixture in which the silicone rubber compositions X-1 and Y-2 were mixed at each 100 parts by mass, and a mixture in which each of the silicone rubber compositions X-1 and Y-2 was separately stored under a condition at 80° C. for 3 days and then mixed at each 100 parts by mass. As the curability at 110° C., T10, T90, and (T90-T10) were measured with Rheometer MDR2000 (manufactured by Alpha Technologies Inc.). Table 1 shows the results.

[0129] Furthermore, the silicone rubber compositions X-1 and Y-2 were injection-molded at a ratio of 1:1 with an injection molding machine (manufactured by ARBURG GmbH, product name: Allrounder 420C). Table 1 shows an appearance of the composition and availability of restarting the molding after leaving the composition in the machine for 2 days.

Comparative Example 1

Preparation Condition of Composition X-3

[0130] Into 100 parts of the silicone rubber base A, 13.08 parts of a dimethylpolysiloxane (A2) blocked at both terminals of the molecular chain with dimethylvinylsiloxy groups and having an average polymerization degree of 220, 2.31 parts of a dimethylpolysiloxane (A3) blocked at both terminals of the molecular chain with trimethylsiloxy groups, having 5 mol % of methyl groups in side chains (that is, monovalent groups or atoms bonded to a silicon atom in a di organosiloxane unit constituting the main chain, the same applies hereinafter) substituted with vinyl groups, and having an average polymerization degree of 200, and 0.39 parts of a toluene solution (C-1) of a complex of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (1 mass % of platinum atom) were added. The mixture was stirred for 30 minutes to obtain a uniform silicone rubber composition X-3.

Preparation Condition of Composition Y-3

[0131] Into 100 parts of the silicone rubber base A, 10.77 parts of a dimethylpolysiloxane (A3) blocked at both terminals of the molecular chain with trimethylsiloxy groups, having 5 mol % of methyl groups in side chains (that is, monovalent groups or atoms bonded to a silicon atom in a diorganosiloxane unit constituting the main chain, the same applies hereinafter) substituted with vinyl groups, and having an average polymerization degree of 200, and 5.15 parts of a methylhydrogenpolysiloxane (B) blocked at both terminals of the molecular chain with trimethylsiloxy groups and having SiH groups on the side chain (dimethylsiloxane-methylhydrogensiloxane copolymer blocked at both terminals of the molecular chain with trimethylsiloxy groups, polymerization degree: 64, SiH group amount: 0.0113 mol/g) as a crosslinker were added, and 0.08 parts of ethynylcyclohexanol (E-1-1) (acetylene/Pt atom=38 mol/mol) as a reaction inhibitor was added, and the mixture was stirred for 30 minutes to obtain a uniform silicone rubber blend Y-3.

[0132] The silicone rubber compositions X-3 and Y-3 were mixed at each 100 parts by mass to measure viscosities at 25° C. and at a shearing rate of 0.9 s.sup.−1. The viscosities, η.sub.0 and η.sub.24, were an initial viscosity and a viscosity after 24 hours, respectively. Table 1 shows the results.

[0133] Prepared were the mixture in which the silicone rubber compositions X-3 and Y-3 were mixed at each 100 parts by mass, and a mixture in which each of the silicone rubber compositions X-3 and was separately stored. under a condition at 80° C. for 3 days and. then mixed at each 100 parts by mass. As the curability at 110° C., T10, T90, and (T90-T10) were measured with Rheometer MDR2000 (manufactured by Alpha Technologies Inc.), Table 1 shows the results.

[0134] Furthermore, the silicone rubber compositions X-3 and Y-3 were injection molded at a ratio of 1:1 with an injection molding machine (manufactured. by ARBURG GmbH, product name: Allrounder 420C). Table 1 shows an appearance of the composition and availability of restarting the molding after leaving the composition in the machine for 2 days.

Comparative Example 2

[0135] The silicone rubber compositions X-3 and Y-1 were mixed at each 100 parts by mass to measure viscosities at 25° C. and at a shearing rate of 0.9 s.sup.−1. The viscosities, η.sub.0 and η.sub.24, were an initial viscosity and a viscosity after 24 hours, respectively. Table 1 shows the results.

[0136] Prepared were the mixture in which the silicone rubber compositions X-3 and Y-1 were mixed at each 100 parts by mass, and a mixture in which each of the silicone rubber compositions X-3 and Y-1 was separately stored under a condition at 80° C. for 3 days and then mixed at each 100 parts by mass. As the curability at 110° C., T10, T90, and (T90-T10) were measured with Rheometer MDR2000 (manufactured by Alpha Technologies Inc.). Table 1 shows the results.

[0137] Furthermore, the silicone rubber compositions X-3 and. Y-1 were injection -molded at a ratio of 1:1 with an injection molding machine (manufactured by ARBURG GmbH, product name: Allrounder 420C). Table 1 shows an appearance of the composition and availability of restarting the molding after leaving the composition in the machine for 2 days.

Comparative Example 3

[0138] The silicone rubber compositions X-3 and Y-1 were mixed at a ratio of 120 and 80 parts by mass to measure viscosities at 25° C. and at a shearing rate of 0.9 s.sup.−1. The viscosities, η.sub.0 and η.sub.24, were an initial viscosity and a viscosity after 24 hours, respectively. Table 1 shows the results.

[0139] Prepared were the mixture in which the silicone rubber compositions X-3 and Y-1 were mixed at a ratio of 120 and 80 parts by mass, and a mixture in which each of the silicone rubber compositions X-3 and Y-1 was separately stored under a condition at 80° C. for 3 days and then mixed at a ratio of 120 and 80 parts by mass. As the curability at 110° C., T10, T90, and (T90-T10) were measured with Rheometer MDR2000 (manufactured by Alpha Technologies Inc.). Table 1 shows the results.

[0140] Furthermore, the silicone rubber compositions and Y-1 were injection-molded at a ratio of 3:2 with an injection molding machine (manufactured by AREURG GmbH, product name: Allrounder 420C). Table 1 shows an appearance of the composition and availability of restarting the molding after leaving the composition in the machine for 2 days.

Comparative Example 4

[0141] The silicone rubber compositions X-3 and Y-1 were mixed at a ratio of 140 and 60 parts by mass to measure viscosities at 25° C. and at a shearing rate of 0.9 s.sup.−1. The viscosities, η.sub.0 and η.sub.24, were an initial viscosity and a viscosity after 24 hours, respectively. Table 1 shows the results.

[0142] Prepared were the mixture in which the silicone rubber compositions X-3 and Y-1 were mixed at a ratio of 140 and 60 parts by mass, and a mixture in which each of the silicone rubber compositions X-3 and Y-1 was separately stored under a condition at 80° C. for 3 days and then mixed at a ratio of 140 and 60 parts mass. As the curability at. 110° C., T10, T90, and (T90-T10) were measured with Rheometer MDR2000 (manufactured by Alpha Technologies Inc.). Table 1 shows the results.

[0143] Furthermore, the silicone rubber compositions X-3 and Y-1 were injection-molded at a ratio of 7:3 with an injection molding machine (manufactured by ARBLIRG GmbH, product name: Allrounder 420C). Table 1 shows an appearance of the composition and availability of restarting the molding after leaving the composition in the machine for 2 days.

Comparative Example 5

Preparation Condition of Composition X-4

[0144] Into 100 parts of the silicone rubber base A, 13.08 parts of a dimethylpolysiloxane (A2) blocked at both terminals of the molecular chain with dimethylvinylsiloxy groups and having an average polymerization degree of 220, 2.31 parts of a dimethylpolysiloxane (A3) blocked at both terminals of the molecular chain with trimethylsiloxy groups, having 5 mol % of methyl groups in side chains (that is, monovalent groups or atoms bonded to a silicon atom in a diorganosiloxane unit constituting the main chain, the same applies hereinafter) substituted with vinyl groups, and having an average polymerization degree of 200, and 0.31 parts of the benzotriazole derivative (D1) (benzotriazoie derivative/Pt atom=48 mol/mol) as a reaction inhibitor were added, and 0.39 parts of a toluene solution. (C-1) of a complex of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (1 mass % of platinum atom) was added. The mixture was stirred for 30 minutes to obtain a uniform. silicone rubber composition X-4.

[0145] The silicone rubber compositions X-4 and Y-3 were mixed at each 100 parts by mass to measure viscosities a, 25° C. and at a shearing rate of 0.9 s.sup.−1. The viscosities, η.sub.0 and η.sub.24, were an initial viscosity and a viscosity after 24 hours, respectively. Table 1 shows the results.

[0146] Prepared were the mixture in which the silicone rubber compositions X-4 and Y-3 were mixed at each 100 parts by mass, and a mixture in which each of the silicone rubber compositions X-4 and Y-3 was separately stored under a condition at 80° C. for 3 days and then mixed each 100 parts mass. As the curability at 110° C., T10, T90, and (T90-T10) were measured with. Rheometer. MDR2000 (manufactured by Alpha Technologies Inc.). Table shows the results.

[0147] The silicone rubber compositions X-4 and Y-3 were injection-molded at a ratio of 1:1 with an injection molding machine (manufactured by ARBURG GmbH, product name: Allrounder 420C), Table 1 shows an appearance of the composition and availability of restarting the molding after leaving the composition in the machine for 2 days.

Comparative Example 6

[0148] Preparation Condition of Composition X-5

[0149] Into 100 parts of the silicone rubber base A, 13.08 parts of a dimethylpolysiloxane (A2) blocked at both terminals of the molecular chain with dimethylvinylsiloxy groups and having an average polymerization degree of 220, 2.31 parts of a dimethylpolysiloxane (A3) blocked at both terminals of the molecular chain with trimethylsiloxy groups, having 5 mol % of methyl groups in side chains (that is, monovalent groups or atoms bonded to a silicon atom in a diorganosiloxane unit constituting the main chain, the same applies hereinafter) substituted with vinyl groups, and having an average polymerization degree of 200, and 0.39 parts of a toluene solution (C-1) of a complex of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (1 mass % of platinum atom) were added. The mixture was stirred for 30 minutes to obtain a uniform silicone rubber composition X-5.

Preparation Condition of Composition Y-4

[0150] Into 100 parts of the silicone rubber base A, 10.77 parts of a dimethylpolysiloxane (A3) blocked at both terminals of the molecular chain with trimethylsiloxy groups, having 5 mol % of methyl groups in side chains (that is, monovalent groups or atoms bonded to a silicon atom in a diorganosiloxane unit constituting the main chain, the same applies hereinafter) substituted with vinyl groups, and having an average polymerization degree of 200, 5.15 parts of a methylhydrogenpolysiloxane (P) blocked at both terminals of the molecular chain with trimethylsiloxy groups and having SiH groups on the side chain (dimethylsiloxane-methylhydrogensiloxane copolymer blocked. at both terminals of the molecular chain with trimethylsiloxy groups, polymerization degree: 64, SiH group amount: 0.0113 mol/g) as a crosslinker, and 0.31 parts of the benzotriazole derivative (D1) (benzotriazole derivative/Pt atom=48 mol/mol) were added, and 0.08 parts of ethynylcyclohexanol (E1-1) (acetylene/Pt atom=38 mol/mol) and 0.31 parts (91 moles relative to Pt atom) of 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane (E-2) were added as reaction. inhibitors. The mixture was stirred for 30 minutes to obtain a uniform silicone rubber blend Y-4.

[0151] The silicone rubber compositions X-5 and Y-4 were mixed at each 100 parts by mass to measure viscosities at 25° C. and at a shearing rate of 0.9 s.sup.−1. The viscosities, η.sub.0 and η.sub.24, were an initial viscosity and a viscosity after 24 hours, respectively. Table 1 shows the results.

[0152] Prepared were the mixture in which the silicone rubber compositions X-5 and Y-4 were mixed at each 100 parts by mass, and a mixture in which each of the silicone rubber compositions X-5 and Y-4 was separately stored under a condition at 80° C. for 3 days and then. mixed at each 100 parts by mass. As the curability at 110° C., T10, T90, and (T90-T10) were measured with Rheometer MDR2000 (manufactured by Alpha Technologies Inc.). Table 1 shows the results.

[0153] Furthermore, the silicone rubber composition X-5 and Y-4 were injection-molded at a ratio of 1:1 with an injection molding mach machine (manufactured. by ARBURG GmbH, product name: Allrounder 420C). Table 1 shows an appearance of the composition and availability of restarting the molding after leaving the composition in the machine for 2 days.

Comparative Example 7

Preparation Condition of Composition (1)

[0154] Into 100 parts of t , silicone rubber base A, 13.08 parts of a dimethylpolysiloxane (A2) blocked at both terminals of the molecular chain with dimethylvinylsiloxy groups and having an average polymerization degree of 220, 2.31 parts of a dimethylpolysiloxane (A3) blocked at both terminals of the molecular chain with trimethylsiloxy groups, having 5 mol % of methyl groups in side chains (that is, monovalent groups or atoms bonded to a silicon atom in a diorganosiloxane unit constituting the main chain, the same applies hereinafter) substituted with vinyl groups, and having an average polymerization degree of 200, 0.04 parts of ethynylcyclohexanol (E1-1) (acetylene/Pt atom=19 mol/mol) as a reaction inhibitor, and 0.39 parts of a toluene solution (C-1) of a complex of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (1 mass % of platinum atom) were added. The mixture was stirred. for 30 minutes to obtain a uniform silicone rubber composition X-6. However, the appearance became black, and thereby the investigation was abandoned.

TABLE-US-00001 TABLE 1 Example Item Unit 1 2 3 4 5 Composition X parts 0.31 0.31 0.31 0.31 0.31 Addition amount of inhibitor Composition X mol/mol 91 91 91 456 91 Inhibitor/Pt atom Mixing Composition X % 50 60 70 50 50 ratio Composition Y % 50 40 30 50 50 Shearing Initial η.sub.0 Pa .Math. s 1100 1040 1040 1040 1060 viscosity After 24 hrs Pa .Math. s 1300 3820 4180 1150 3230 0.9 S−1 η.sub.24 Curability T10 sec 31 30 31 31 31 initial T90 sec 58 55 58 58 58 T90 − T10 sec 27 25 27 28 28 Curability T10 sec 31 31 29 32 32 after 80° C. T90 sec 59 60 60 59 60 for 3 days T90 − T10 sec 28 29 31 28 28 Evaluation fed and Appearance of Liquid Liquid Liquid Liquid Liquid with left for composition injection 2 days Availability Yes Yes Yes Yes Yes molding of restarting machine molding Comparative Example Item Unit 1 2 3 4 5 6 Composition X parts — — — — 0.31 — Addition amount of inhibitor Composition X mol/mol — — — — 48 — Inhibitor/Pt atom Mixing Composition X % 50 50 60 70 50 50 ratio Composition Y % 50 50 40 30 50 50 Shearing Initial η.sub.0 Pa .Math. s 1030  1010 1030  1030  1300 1010 viscosity After 24 hrs Pa .Math. s Cured 6300 Cured Cured 1400 6120 0.9 S−1 η.sub.24 Curability T10 sec 31 31 31 31 39 31 initial T90 sec 58 59 60 60 66 61 T90 − T10 sec 27 28 29 29 27 30 Curability T10 sec 31 31 32 32 40 32 after 80° C. T90 sec 58 58 59 60 126 61 for 3 days T90 − T10 sec 28 28 27 28 86 29 Evaluation fed and Appearance of Cured Highly Cured Cured Liquid Highly with left for composition viscous viscous injection 2 days Availability No No No No Yes No molding of restarting machine molding

[0155] Any of the inventive Examples have a sufficiently low shearing viscosity even after the lapse of 24 hours from mixing, and also has excellent curing performance of course when cured immediately after prepared and even when. prepared and then left at 80° C. for 3 days and then mixed and cured. In addition, in injection molding, any of the mixture fed and left for 2 days are quid, and capable of restarting the molding.

[0156] Meanwhile, Comparative Examples a to 4 and 6 resulted in the composition that was cured or had a high shearing viscosity after the lapse of 24 hours from mixing. In injection molding, the mixture fed and then left for 2 days was cured or became highly viscous, and the molding could not be restarted. Comparative Example 5, in which the component (D) was added. into the composition X side, resulted good shearing viscosity and good injection molding evaluation with an injection molding machine, but deteriorated the curing performance in the test for evaluating the storability when the mixture was prepared and left at 80° C. for 3 days and then mixed and cured.

[0157] It should be noted that the present invention is not limited to the above-described embodiments. The embodiments are just examples, and any examples that have substantially the same feature and demonstrate the same functions and effects as those in the technical concept disclosed in claims of the present invention are included in the technical scope of the present invention.