JPS6198764A - silicone rubber composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a silicone rubber composition having new and new crosslinking points, more particularly having 5 or more carbon atoms and having at least The present invention relates to a silicone rubber composition in which the crosslinking point is a monovalent hydrocarbon group having a carbon-carbon double bond via one carbon atom.

[Technical background of the invention and its problems] A common crosslinking point group in silicone rubber is a vinyl group.

Therefore, the base polymer, vinyl group-containing polyorganosiloxane, is molded using an organic peroxide as a vulcanizing agent, or a platinum compound and a polyorganohydrodiene siloxane are added and blended to form a silicone rubber molded product. can be obtained.

On the other hand, general organic synthetic rubbers are vulcanized using sulfur or a sulfur supplying agent. In some organic synthetic rubbers (eg, EPDM, butyl rubber), resin vulcanization using substituted or unsubstituted alkylphenol resins or quinoid vulcanization using quinoids is also performed.

However, conventional silicone rubber compositions containing vinyl groups as crosslinking point groups cannot be vulcanized and molded using the above-mentioned general organic synthetic rubber vulcanizing agents.

Purpose of the Invention] Therefore, the present inventors have conducted extensive research on silicone rubber compositions that can be vulcanized with sulfur, sulfur-supplying agents, substituted or unsubstituted alkylphenol resins, or quinoids, which are used in general organic synthetic rubbers. Through this research, a silicone rubber composition having a novel crosslinking point was discovered, and the present invention was completed.

[Structure of the Invention] That is, the present invention provides (A) an organic group selected from monovalent substituted and unsubstituted hydrocarbon groups bonded to a silicon atom, in which 1.98 to 2.02 organic groups are present per silicon atom; , is a monovalent hydrocarbon group in which at least two of the total number of groups have 5 or more carbon atoms and a double bond between carbon atoms via at least one carbon atom from a silicon atom. , Polyorgano Shirogiza 2 with a degree of polymerization of 100 or more
100 parts by weight (B) 5 to 200 parts by weight of an amorphous filler with a specific surface area of 507O2/13 or more (C) A vulcanizing agent selected from the group consisting of sulfur, a sulfur supply agent, substituted or unsubstituted alkylphenol resins, and quinoids A silicone rubber composition characterized by comprising 0.1 to 25 parts by weight.

The polyorganosiloxane (A) used in the present invention is represented by the general formula, and contains some R' Si 03/2 in the molecule.
unit or Si02 unit. Here, R2 and R3 are each the same or complementary organic group, and are M-type or unsubstituted 1! 11 [
selected from i hydrocarbon groups. R1 is an organic group selected from the same range as R2 and R3, or part or all of it is water I
It may be Ls or an alkoxy group.

Such monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, hexyl, and decyl groups; alkenyl groups such as vinyl and allyl groups; aryl groups such as phenyl and tolyl groups; ; aralkyl groups such as β-phenylethyl group and β-phenylpropyl group; substituted hydrocarbon groups such as chloromethyl group, cyanethyl group, trifluoropropyl group, and chlorophenyl group; In order to achieve this, it is necessary to have at least 2M hydrocarbon groups in one molecule, which have 5 or more carbon atoms and a carbon-carbon double bond via at least one carbon atom from a silicon atom. be. Examples of such groups include ethylidene norbornyl group, methylene norbornyl group, dicyclopentenyl group, 4-pentenyl group, 4-hexenyl group, cyclooctenyl group, etc., and even one type may contain two or more types. However, an alkylidene norbornyl group is most preferred from the viewpoint of easy availability of raw materials and reactivity of the double bond.

If there is one or more hydrocarbon groups in one molecule of polyorganosiloxane having five or more carbon atoms and a carbon-carbon double bond via at least one carbon atom from a silicon atom, , vulcanization is not performed with the vulcanizing agent of the present invention.

From this point of view, at least two groups are required in one molecule of polyorganosiloxane, and there is no particular restriction on the upper limit of the number, but in order to obtain a silicone rubber with good physical properties, all organic groups bonded to silicon atoms must be present. 0.05-5 for
It is preferable to contain mol%.

The bonding position of such a group is not limited, and the silicon atom may be located in the middle or at the end of the molecular chain.

The number of specific groups bonded to silicon atoms in the polyorganosiloxane (A) is 1.98 to 2.0 per silicon atom.
Selected from 02 ranges. If the number of specific groups is less than 1.98, a good rubber-like elastic body cannot be obtained, and if it exceeds 2.02, a polymerization degree of 100 or more cannot be obtained.

The degree of polymerization (n11) of the polyorganosiloxane (A>) needs to be 100 or more, preferably 1.000 or more in order to obtain 1q of silicone rubber with good mechanical properties. When considering the workability of the step of obtaining a homogeneous composition, the range is preferably from 2.000 to 20.000.

The inorganic filler (B) used in the present invention is a component for imparting various physical properties, particularly mechanical strength, to the silicone rubber molded article obtained from the composition of the present invention. In order to impart sufficient mechanical strength, the specific surface area of the unmodified filler needs to be 5C) m2/(1 or more, especially 1
00-300TI+2/(+ is preferable.

Examples of such inorganic fillers include reinforcing silicas well known in the art such as fumed silica and precipitated silica, and carbon blacks such as 1-nes black, channel black, thermal black, and acetylene black depending on the purpose. be done.

These fillers may be used as they are, or may be surface-treated with a paid silicon compound, organic resin acid, organic resin acid salt, or the like.

The blending amount of the inorganic filler (B) is in the range of 5 to 200 parts by weight based on 2100 parts by weight of the polyorganosimixer (A). If the amount of (B) is less than 5 parts by weight, a sufficient reinforcing effect cannot be obtained, and if it exceeds 200 parts by weight, it is difficult from the viewpoint of processability.

The vulcanizing agent (C) used in the present invention is a component for vulcanizing the composition consisting of the polyorganosiloxane (A) and the inorganic filler (B), and includes sulfur, a sulfur supply agent, a substituted or unsubstituted alkylphenol resins and quinoids.

Specific examples of vulcanizing agents include sulfur-supplying agents such as tetramethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, and dithiodimorboline; Examples thereof include substituted alkylphenes, nor resins; quinoids such as p-quinonedioxime and p,l-dibenzoylquinonedioxime. These vulcanizing agents may be used alone or as a mixture of two or more.

The blending amount of the vulcanizing agent (C) is selected from the range of 0.1 to 25 weight parts based on the iooim parts of the polyorganosiloxane (A). If the blend ω of the vulcanizing agent in (C) is less than 0.111 parts, vulcanization will not be sufficient, and if it exceeds 25 parts, not only will there be no particular effect, but the physical properties of the resulting silicone rubber molded product will be affected. This is undesirable as it has a negative impact.

The silicone rubber composition of the present invention includes, in addition to component (A),
Vinyl group-containing polysiloxanes such as polymethylvinylsiloxane and polymethylphenylvinylsiloxane may also be used together as a pace polymer. Also(
△) In addition to ingredients (C), crushed quartz, diatomaceous earth, titanium oxide, aluminum oxide, zinc oxide, magnesium oxide, magnesium carbonate, calcium carbonate, magnesium silicate, aluminum sulfate, calcium sulfate, barium sulfate, mica, asbestos , glass powder, etc. Further, known heat resistance improvers, flame retardants, vulcanization aids, processing aids, coloring agents, etc. may be blended.

The silicone rubber composition of the present invention comprises the above-mentioned (A) to (C).
It is obtained by blending the components and various additives as necessary and mixing them uniformly, and becomes a rubber-like elastic body by heating.

[Examples of the Invention] The present invention will be explained below with reference to Examples. In the examples, all parts indicate parts by weight.

Examples 1-8 296 parts of octamethylcyclotetrasiloxane, 16.8 parts of heptamethylethylidenenorbornylcyclotetrasiloxane, and 0.1 part of decamethyltetrasiloxane
8 parts of the mixture was heated to 14.0 to 150°C, 0.007 part of potassium hydroxide was added thereto for polymerization reaction for 15 hours, and then 0.004 part of phosphoric acid was added for neutralization. The obtained product contained 1 mol % of methylethylidenenorbornylsiloxy units and had a degree of polymerization of 7. It was a polyorganosiloxane of O,,OO.

Polydimethylsiloxane 2 having a viscosity of 50C3t and having its ends blocked with water HN to 100 parts of this polyorganosiloxane
．． 0 parts, fumed silica with a specific surface area of 110 m2/g (Aerosil R97) surface-treated with diorganodichlorosilane
2. 50 parts (manufactured by Degutsusa) and 5.0 parts of zinc oxide were mixed thoroughly with two rolls, and added with vulcanizing agents and vulcanization accelerators of the types and types shown in Table 1 below. Silicone rubber composition samples 1 to 4 (Examples 1 to 4)
) was obtained. Separately, the above polyorganosiloxane 100
In place of the above-mentioned fumed silica, a specific surface area of 70 v2 is added.
/ Q acetylene black (Denka Black, manufactured by Denki Kagaku Co., Ltd.) 50 parts was mixed thoroughly in the same manner as above with two rolls, and the types and additions shown in Table 1 below were added. A sulfurizing agent was added and blended to obtain silicone rubber composition samples 5 to 8 (Examples 5 to 8). Press these samples at a pressure of 150! Press vulcanization was performed using LF LCD for 20 minutes at the press temperature shown in Table 1 to obtain a thickness of 2.
A sheet-like rubber of mm was obtained. Roughly these sheets were post-vulcanized at 200°C for 2 hours, and JISC2123
Hardness, tensile strength, elongation, and tear strength were measured according to the following.

The results are shown in Table 1.

Comparative Examples 1 to 8 As comparative examples, 296 parts of octamethylcyclotetrasiloxane, 3.5 parts of tetramethyltetravinylcyclotetrasiloxane, and decamethyltetrasiloxane were used instead of the ethylidenenorbornyl group-containing polyorganosiloxane of Examples 1 to 8. 140-150 of a mixture of 0.18 parts of siloxane
℃ and added 0.007 part of potassium hydroxide to 15
A vinyl group-containing polyorganosiloxane containing 1 mol% of methylvinylsiloxane units and a degree of polymerization of 7.000 was used ( Comparative samples 1 to 8 (Comparative Examples 1 to 8) of silicone rubber compositions having the same compositions as those of Examples 1 to 8 were prepared and compared.The results are shown in Table 1. Comparison sample number 1~
4 is fumed silica (Aerosil R-972>5-0 parts,
Comparative sample numbers 5 to 8 used 50 parts of acetylene black (Denka Black).

(Leaving space below) Example 9 296 parts of octamethylcyclotetrasiloxane, 32.4 parts of hexamethyldiethylidenenorbornylcyclotetrasiloxane, and 0.2 parts of decamethyltetrasiloxane.
22 parts of the mixture was heated to 140-1'50°C, 0.009 part of potassium hydroxide was added thereto, the polymerization reaction was carried out for 15 hours, and then 0.005 part of phosphoric acid was added for neutralization. The obtained product contained 3 mol% of methylethylidenenorbornylsiloxy units and a degree of polymerization of 6. It was a polyorganosiloxane of O,OO.

To 100 parts of this polyorganosiloxane, add 11 parts of water at the end.
i! 3 parts of polydimethylsiloxane oil with a viscosity of 50C8t sealed with 2 units, 30 parts of precipitated silica with a specific surface area of 240i2/9, Tsubu Seal VN3 (manufactured by Nippon Silica Co., Ltd.), a furnace black with a specific surface area of 100T112/CI, AA 25 parts of Chemical Shaso), 5 parts of zinc oxide, and 1 part of stearic acid were mixed thoroughly with two rolls, and added with dipentamethylenethiuram tetrasulfide (Tsukusela TRA, manufactured by Anauchi Shinko Kagaku Co., Ltd.) as a vulcanizing agent. ) 3 parts, N-cyclohexyl-2 as a vulcanization accelerator
-Benzothiazoylsulfenamide (Tuxela CZ)
, manufactured by Ouchi Shinsashi Kagakusha) 1. -0 parts were added and blended to obtain silicone rubber composition sample 9.

This sample was press-vulcanized at a press pressure of 15 Qkgr/cj for 20 minutes and a press temperature of 17-0°C to obtain a rubber sheet with a thickness of 2 mm. Furthermore, this sheet was post-vulcanized at 200℃ for 2 hours, and the JIS
Hardness, tensile strength, elongation and tear strength were measured according to C2123. The results are shown in Table 2.

Example 10 296 parts of octamethylcyclotetrasiloxane, 8.3 parts of heptamethylethylidenenorbornylcyclotetrasiloxane, 8.3 parts of octaphenylschiff autotetrasiloxane.
A mixture of 2 parts and 0.26 parts of decamethyltetrasiloxane is heated to 140-150°C, and 0.2 parts of potassium hydroxide is added.
0.009 parts of phosphoric acid was added thereto and the polymerization reaction was carried out for 200 hours, and then 0.005 parts of phosphoric acid was added to perform neutralization. The obtained product has 0.00 methylethylidenenorbornylsiloxy units.
The polyorganosiloxane contained 5 mol%, 1 mol% of diphenylsiloxy units, and a degree of polymerization of 5,000.

To 100 parts of this polyorganosiloxane, 4 parts of polyorganosiloxane oil (viscosity [50 cSt) whose ends are capped with methoxy groups and whose molar ratio of dimethylsiloxy units to diphenylsiloxy units is 2:1, and a specific surface area of 200
45 parts of fumed silica (Aerosil 200, manufactured by Nippon Aerosil Co., Ltd.) of m'/g and 10 parts of zinc oxide were thoroughly kneaded using two rolls. 250-I, manufactured by Sumitomo Chemical Co., Ltd.) and 5.0 parts of an alkylphenol formaldehyde resin (Takki Roll 201, manufactured by Sumitomo Chemical Co., Ltd.) were added and blended to obtain silicone rubber composition sample 10.

These samples were pressed at a pressure of 150 kQf/crl for 20
Press vulcanization was performed for 1 minute at a press temperature of 190° C. to obtain a rubber sheet with a thickness of 2 mm. Furthermore, this sheet was post-vulcanized at 200℃ for 2 hours, and the JIS
Hardness, tensile strength, elongation and tear strength were measured according to G 2123. The results are shown in Table 2.

Example 11 296 parts of octamethylcyclotetrasiloxane, 26 parts of heptamethyldicyclopentenylcyclotetrasiloxane
．． A mixture of 4 parts and 0.13 parts of decamethyltetrasiloxane was heated to 140 to 150°C, 0.007 parts of potassium hydroxide was added and polymerized for 15 hours, and then 0.004 parts of phosphoric acid was added. carried out neutralization. The obtained product has 1. methyldicyclobentenylcyxy units.
It was a polyorganosiloxane with a concentration of 5 mol % and a degree of polymerization of 10.000.

To 100 parts of this polyorganosiloxane, 5 parts of polydimethylsiloxane with a viscosity of 50C8t and whose terminals are capped with hydroxyl groups, 15 parts of precipitated silica (Nip Seal VN3, manufactured by Nippon Silica Co., Ltd.) with a specific surface area of 240112/(), and a specific surface area of 7
0TO'/(l) 35 parts of acetylene black (Denka Black, manufactured by Denki Kagaku Co., Ltd.), 5 parts of zinc oxide, stearin R
1 part of sulfur and 1.0 part of sulfur as a vulcanizing agent and N-cyclohexyl-2-benzothiazoylsulfenamide (Tuxeler) as a vulcanization accelerator. Silicone rubber composition sample 11 was obtained by adding and blending 0.5 part of CZ (manufactured by Iriuchi Shinko Kagaku Co., Ltd.) and 1.0 part of tetramethylthiuram disulfide (Suncella TT1, manufactured by Sanshin Kagaku Co., Ltd.).

This sample was press-vulcanized at a press pressure of 15 Qkgf/cd for 20 minutes at a press temperature of 170°C to obtain a rubber sheet with a thickness of 2 mm. Furthermore, this sheet was post-vulcanized at 200°C for 2 hours, and JIS C2
Hardness, tensile strength, elongation, and tear strength were measured according to 123. The results are shown in Table 2.

Example 12 296 parts of octamethylcyclotetrasiloxane, 15 parts of heptamethyl(4-hexenyl)cyclotetrasiloxane
．． 2 parts, 0.672 parts of tetramethyltetravinylcyclotetrasiloxane and 0.2 parts of decamethyltetrasiloxane.
26 parts of the mixture was heated to 140 to 150°C, 0.007 part of potassium hydroxide was added thereto, the polymerization reaction was carried out for 15 hours, and then 0.004 part of phosphoric acid was added for neutralization. The obtained product contains 1 mol% of methyl(4-hegycenyl)siloxy units and 0.2 mol% of methylvinylsiloxy units.
, a polyorganosiloxane with a degree of polymerization of 5,000.

To 100 parts of this polyorganosiloxane, a specific surface area of 20
40 parts of fumed silica (Aerosil 2001 manufactured by Nippon Aerosil Co., Ltd.) of 0 m2/g and 5 parts of zinc oxide were mixed thoroughly with two rolls, and 0.5 part of sulfur as a vulcanizing agent was added to accelerate vulcanization. As agents, N-cyclohexyl-2-benzothiazoylsulfenamide (Tsukusera CZ, manufactured by Iriuchi Shinko Kagaku Co., Ltd. > 2.0 parts, tetramethylthiuram disulfite (Sunsera TT1 manufactured by Sanshin Kagaku Co., Ltd.) 1.0 parts , 1.0 part of dipentamethylenethiuram tetrasulfide (Tsukusela TRA, manufactured by Iriuchi Shinko Kagaku Co., Ltd.) was added and blended to obtain silicone rubber composition sample 12. This sample was pressed at a press pressure of 150 kc+f/ci for 20 minutes at a press temperature of 170 ml. A sheet-like rubber having a thickness of 2 mm was obtained by press vulcanization at .degree.

Further, this sheet was post-vulcanized at 200° C. for 2 hours, and its hardness, tensile strength, elongation, and tear strength were measured according to JIS C2123. The results are shown in Table 2.

[Effects of the Invention] As explained above, according to the present invention, a silicone rubber composition that can be vulcanized using a general vulcanizing agent for organic synthetic rubber can be obtained.

Molded articles obtained from the silicone rubber composition of the present invention can be widely used as tubes, profile extrusion molded articles, packings, and gaskets.

Claims (4)

[Claims] (1) (A) There are 1.98 to 2.02 organic groups selected from monovalent substituted and unsubstituted hydrocarbon groups bonded to silicon atoms per silicon atom, and the total number of organic groups is At least two of them are monovalent hydrocarbon groups having five or more carbon atoms, a carbon-carbon double bond via at least one carbon atom from a silicon atom, and a degree of polymerization of 100 or more. 100 parts by weight of polyorganosiloxane (B) Inorganic filler with a specific surface area of 50 m^2/g or more 5
~200 parts by weight (C) A silicone rubber composition comprising 0.1 to 25 parts by weight of a vulcanizing agent selected from the group consisting of sulfur, a sulfur supply agent, a substituted or unsubstituted alkylphenol resin, and a quinoid. (2) The monovalent hydrocarbon group of (A) having 5 or more carbon atoms and having a carbon-carbon double bond via at least one carbon atom from a silicon atom accounts for 0.05 of all organic groups. ~5
A silicone rubber composition according to claim 1 in which the silicone rubber composition is present in mol %. (3) The monovalent hydrocarbon group in (A) having 5 or more carbon atoms and having a carbon-carbon double bond via at least one carbon atom from a silicon atom is an alkylidene norbornyl group. A silicone rubber composition according to claim 1. (4) The silicone rubber composition according to claim 1, wherein (A) has a degree of polymerization of 1,000 or more.