JPH04218544A - Rubber composition and production thereof - Google Patents

Abstract

PURPOSE:To provide a rubber composition having the merits of both an organic rubber and a silicone rubber from an organic rubber and silicone rubber using a specific compatibilizing agent. CONSTITUTION:A method for producing a rubber composition characterized by using a kneaded material obtained by heating and kneading 100 pts.wt. ethylene-bases polymer and 50-250 pts.wt. organopolysiloxane expressed by the formula R<1>aR<2>bSiO4-a-b/2 (A) (R<1> is non-substituted or substituted monovalent hydrocarbon group without aliphatic unsaturated group; 0<a<1, 0.5<b<3 and 1<a+b<3) as a compatibilizing agent when an organic rubber is heated and kneaded with a silicone rubber to produce a rubber composition.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition comprising an organic rubber and a silicone rubber, and a method for producing the same using a specific compatibilizing agent. More specifically, the present invention includes:
The present invention relates to a method for producing a rubber composition that has both the advantages of organic rubber and silicone rubber. The rubber composition made according to the present invention can be used for electronic parts, mechanical parts, medical supplies, daily necessities,
Used for sporting goods, leisure goods, health goods, civil engineering and construction goods, agricultural goods, etc.

0002

[Prior Art] Conventionally, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, ethylene-propylene-terpolymer rubber, butyl rubber, acrylic rubber, etc. have been used to improve tensile strength, tear resistance, and durability, respectively. Wear resistance, flex crack resistance, oil resistance, gasoline resistance (solvent resistance or volatile oil resistance), acid resistance,
It has inherent excellent properties such as alkali resistance, while silicone rubber has properties that the above-mentioned rubbers do not have, such as heat resistance, weather resistance, ozone resistance, and cold resistance.

[0003] Therefore, many attempts have been made to mix the two in order to obtain a rubber composition that has the advantages of both. For example, combinations of silicone rubber and polyisobutylene (JP 54-41597), butyl rubber and silicone rubber (JP 56-76444), ethylene-propylene terpolymer or styrene-butadiene copolymer and Hydrodiene polysiloxane (Japanese Patent Publication No. 55-27573), natural rubber or organic synthetic rubber and mercapto group-containing polysiloxane (Japanese Patent Publication No. 55-392)
48), unvulcanized rubber, organopolysiloxane, and organic peroxide (Japanese Patent Publication No. 57-53813), but there are differences in SP value, difference in viscosity, and vulcanization rate due to organic peroxide. There are differences between the two, and it has been difficult to create a blend in which both are uniformly dispersed.

[0004] In order to solve this problem, for example, a silicone rubber and a saturated elastomer are mixed with another elastomer that is compatible with the saturated elastomer (Japanese Unexamined Patent Application Publication No. 1-1999).
No. 8646) has been proposed, but the compatibility with silicone rubber has not been resolved and the dispersion state is not sufficient.

[0005]

[Problems to be Solved by the Invention] The present invention is directed to the present invention, which has hitherto been desired to provide a rubber composition in which organic rubber and silicone rubber are uniformly dispersed. Even when a compatibilizer was used, the compatibility was insufficient, so a rubber composition that had both properties had not been made. However, the present invention has been developed by uniformly kneading the two and creating silicone rubber. heat resistance, weather resistance, ozone resistance, cold resistance and organic rubber tensile strength, tear resistance, abrasion resistance,
An object of the present invention is to provide a method for producing a rubber composition and a rubber composition that have flex crack resistance, oil resistance, gasoline (solvent) resistance, acid resistance, alkali resistance, and the like.

[0006]

[Means for Solving the Problems] The present inventors previously filed a patent application for a moldable kneaded product obtained by heating and kneading an ethylene polymer and an organopolysiloxane (Japanese Patent Application No. 154700/1999). ), the present inventors have used this kneaded product in many applications, but they have researched its use as a compatibilizer, further improved it to be suitable as a compatibilizer, and developed a composition of silicone rubber and organic rubber. The present invention was completed by confirming the optimal value range of each blending ratio through experiments.

That is, the present invention provides the following features: 1) In producing a rubber composition by heating and kneading an organic rubber and a silicone rubber, 100 parts by weight of an ethylene polymer and the formula (A) R1 a R2 b are used as compatibilizers. SiO4-a-b/2
(A) (wherein R1 is an aliphatic unsaturated group, R2
is an unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated group, 0<a<1, 0.5<b<3, 1<a+b<3)
A method for producing a rubber composition, characterized in that a kneaded product having a gel content of 5 to 25% obtained by heating and kneading 50 to 250 parts by weight of an organopolysiloxane represented by the following formula is used. 2) The method for producing a rubber composition as described in 1) above, characterized in that 1.5 to 30 parts by weight of a compatibilizer is used per 100 parts by weight of the total amount of organic rubber and silicone rubber. 3) A rubber composition produced by the production method of 1) above.

In the present invention, organic rubber includes natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, butyl rubber, hydrin rubber, etc. one or more organic rubbers selected from

In the present invention, silicone rubber is produced by ring-opening polymerization of cyclic polysiloxane in the presence of an alkali or acid catalyst, but it is also produced by ring-opening polymerization of a (co)hydrolyzate of organochlorosilane in the presence of a condensation catalyst or an equilibrium catalyst. It can be produced by polymerization in the presence of a chemical catalyst, and when trying to obtain organopolysiloxanes containing various organic groups, the corresponding cyclic polysiloxanes or organochlorosilanes are mixed and copolymerized. It may be something.

The silicone rubber of the present invention is composed of siloxane units such as dimethylsiloxane, methylphenylsiloxane, methylvinylsiloxane, methylfluoroalkylsiloxane, and methylethylidenenorbornenesiloxane, and has a terminal group such as a silanol group, an alkoxy group, a trimethylsilyl group, or a dimethylvinyl group. It is blocked with silyl group, dimethylphenylsilyl group, methylphenylvinylsilyl group, etc., and in order to enable crosslinking with organic peroxide, dimethylvinylsilyl group, ethylidene norbornyl group, ethylidene norbornyl group, etc. are attached to the terminal or skeleton of the molecule. Methylene norbornyl group, dicyclopentenyl group, 4-pentenyl group, 4-hexenyl group, cyclooctenyl group, etc. are 0.02 to 10 mol%, preferably 0.05 mol% of the hydrocarbon groups directly bonded to silicon atoms in the molecule. ~5 mol% is required. The silicone rubber of the present invention may have a linear structure, a partially branched structure, or a three-dimensional structure, and the polymerization amount thereof may be 5.
00-10,000 preferably 1,000-7,000
It is. In the present invention, the mixing ratio of organic rubber and silicone rubber is 3 to 300 (5 to 1900) parts by weight, preferably 30 to 80 (11 to 900) parts by weight or 130 parts by weight of silicone rubber to 100 parts by weight of organic rubber. ~200
Parts by weight. If the amount of silicone rubber is less than 3 (5) parts by weight, the properties of silicone rubber will not be imparted and 300 (
If the amount exceeds 1900 parts by weight, the properties of organic rubber will not be imparted, which is undesirable.

[0011] The compatibilizer used in the present invention is composed of 100 parts by weight of an ethylene polymer and the formula (A) R1 a R2 b SiO4 - a - b / 2
(A) (wherein R1 is an aliphatic unsaturated group, R2
is 50 to 250 parts by weight of an organopolysiloxane represented by an unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated group (0<a<1, 0.5<b<3, 1<a+b<3) It is a kneaded product with a gel content of 5 to 25% obtained by heating and kneading.

The ethylene-based polymer used in the present invention is a polymer containing ethylene as a main component, and includes high-pressure polyethylene, linear low-density polyethylene (LLDPE),
), ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer Copolymer, ethylene-ethyl acrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-vinyl alcohol copolymer, and others.

In the organopolysiloxane represented by formula (A) used in the present invention, examples of the R1 group include a vinyl group, allyl group, acrylic group, methacryl group, etc., and examples of the R2 group include a methyl group. , alkyl groups such as ethyl group and propyl group, alkyl groups such as phenyl group and tolyl group, aryl group such as phenyl group and tolyl group, cycloalkyl group such as cyclohexyl group and cyclobutyl group, and carbon atoms of these hydrocarbon groups. Examples include groups in which a bonded hydrogen group is partially substituted with a halogen atom, a cyano group, a mercapto group, etc., but these may be a combination of the same or different types.

[0014] Furthermore, a is greater than 0 and less than 1, and 0
If it is 1 or more, it will not react with the ethylene polymer, which is undesirable, and if it is 1 or more, a gel-like substance will be formed and the function as a compatibilizer will be lost. a is preferably 0.0004 to 0.06
It is. b is greater than 0.5 and less than 3; if it is less than 0.5, it will be difficult to knead the composition of the present invention and the processability will be poor; if it is greater than 3, the compatibilizer will become too hard, which is not desirable. b is preferably 1-2.

The molecular structure of the organopolysiloxane of the present invention may be any one such as chain, network, three-dimensional network, etc., as long as it falls within the range of formula (A). As the organic silicone compound used in the present invention, for example, those commercially available as tear strength improving materials for silicone rubber can be used. The viscosity at 23° C. of the organic silicone rubber compound represented by formula (A) used in the present invention is 1,000 CS or more, preferably 10,000 to 10,000 CS.
1,000,000 CS is desirable. 1,000
If the viscosity is lower than CS, heating and kneading is difficult, and the organic silicone compound may ooze out from the surface of the molded product.

The organopolysiloxane represented by formula (A) used in the present invention is required in an amount of 50 to 250 parts, preferably 70 to 150 parts, per 100 parts by weight of the ethylene polymer. If it is less than 50 parts, there will be no compatibilizing effect, and if it is more than 250 parts, there will be no compatibilizing effect.

The amount of the compatibilizer of the present invention is 10% of the organic rubber.
1 to 30 parts by weight, preferably 1.5 to 0 parts by weight
Use 10 parts by weight. ) is used in an amount of 1.5 to 30 parts by weight, preferably 3 to 10 parts by weight, based on 100 parts by weight of the total amount with the organic rubber. If it is less than 1.5 parts by weight, no compatibilizing effect will be achieved, and if it is more than 30 parts by weight, the properties of the rubber composition will be lost, which is not desirable.

The compatibilizer of the present invention can be prepared by using a Banbury mixer, twin-screw extruder, or other ordinary kneading equipment (ordinary mixing rolls or internal kneading machine) to produce a compound of 100 to 300
Knead (preferably at 80-200°C).

[0019] Organic peroxide as necessary (however, omit any peroxide having an acyl group [carbon black] or any peroxide having no acyl group [acid] which is a contraindicated catalyst poison).
may be added.

The gel content of the compatibilizer obtained is 5-25%.
If it is less than 5%, it will not exhibit a compatibilizing effect and will bleed onto the surface of the rubber molded product, causing stains and stickiness, which is undesirable. If it is more than 25%, it will exist as islands in the rubber composition. However, it does not exhibit any compatibilizing effect.

The rubber composition of the present invention contains fumed silica, precipitated silica, fine quartz powder, diatomaceous earth, carbon black,
Zinc white, basic magnesium carbonate, activated calcium carbonate, magnesium silicate, titanium oxide, Bengara, cerium oxide, beryllium zirconate, aluminum silicate, calcium sulfate, barium sulfate, asbestos, glass fiber, softener, plasticizer, additive Sulfur aids, anti-aging agents, colorants, flame retardants,
Foaming agents, ultraviolet absorbers, tackifiers, lubricants, titanium coupling agents, silicone coupling agents, etc. may be blended as necessary.

The rubber composition of the present invention includes rubber composition 10.
0.2 to 10 parts by weight of organic peroxide is added as a vulcanizing agent to 0 parts by weight.

[0023] The organic peroxide used in the present invention preferably has a decomposition temperature of 100°C to 220°C with a half-life of 10 minutes, and examples of such peroxides include the following. However, the value in parentheses is the decomposition temperature.

Succinic acid peroxide (110), benzoyl peroxide (110), t-butyl peroxide
2-ethylhexanoate (113), p-chlorobenzoyl peroxide (115), t-butylperoxyisopropyl carbonate (135), t-butylperoxylaurate (140), 2,5-dimethyl-2,
5-di(benzoylperoxy)hexane (140),
t-Butylperoxyacetate (140), di-t-
Butyl peroxyphthalate (140), t-butyl peroxymaleic acid (140), cyclohexanone peroxide (145), t-butyl peroxybenzoate (145), dicumyl peroxide (150), 2,
5-dimethyl-2,5-di(t-butylperoxy)hexane (155), t-butylcumyl peroxide (1
55), t-butyl hydroperoxide (158), di-t-butyl peroxide (160), 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3
(170), di-isopropylbenzene hydroperoxide (170), p-menthane hydroperoxide (1
80), 2,5-dimethylhexane-2,5-dihydroperoxide (213).

[0025] In the present invention, the gel content is determined by heating the sample to 95°C.
The sample was immersed in toluene for 24 hours, dried under vacuum for 24 hours, and calculated from the ratio of the remaining gel amount and the weight of the sample.

The rubber composition of the present invention can be used in a wide variety of applications, and since a part of the compatibilizing agent is composed of an ethylene polymer, it has good processability and is suitable for compression molding,
It can be processed using various molding methods such as transfer molding.

[0027]

[Example] Preparation of compatibilizer Compatibilizer 1 Melt index (190°C, 2160g) 15g/
10 min, 40 parts by weight of ethylene vinyl acetate copolymer (NUC-892, manufactured by Nippon Unicar) with a vinyl acetate content of 20 wt%, a viscosity of 300,000 C at 23°C.
S, silicone gum stock with 1% methyl vinyl silicone content (DK-Q8-782, manufactured by Nippon Unicar) 6
0 parts by weight, 0.05 parts by weight of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane (Perhexa 25B, manufactured by NOF Corporation) and D520-40MWA manufactured by Moriyama Seisakusho Co., Ltd.
- When kneaded for 30 minutes at a resin temperature of 200°C with an H-type kneader, pentaerythritol-tetrakis [3-(3
, 5-di-t-butyl-4-hydroxyphenyl) propionate] (IRGANOX 1010 manufactured by Ciba Geigy) was added and kneading was continued for 5 minutes to obtain compatibilizer 1 with a gel content of 12%. .

Compatibilizer 2 In the above preparation of compatibilizer 1, melt index (190°C, 2
160g) 20g/10min, and an ethylene-ethyl acrylate copolymer (MB-730, manufactured by Nippon Unicar) with an ethyl acrylate content of 35 wt% was used. Obtained.

(Example 1) A rubber composition was prepared using silicone gum stock (Bayer VS Polymer), acrylonitrile butadiene rubber (JSR 230R), and the compatibilizer of the present invention, and vulcanized with an organic peroxide. , and measured its physical properties. For comparison, an experiment was also conducted in which no compatibilizer was used at all. Table 1 shows the composition of each component.
It is as follows.

[0030]

[Table 1]

Kneading recipe: The kneading recipe is as shown below. Blend No. In case 1, run the JSR 230S through the water three times with the cooling water faucet fully open and the roll gap fully tightened, then continue masticating with the roll gap set to 3 on the scale for about 15 minutes. After this, after waiting until the surface of the rubber became smooth, US-A and Perbutyl C were added and kneaded in this order. 3/4 cuts were made three times on each side alternately every 30 seconds, and with the roll gap fully tightened, triangle cutting was performed three times, the roll gap was set appropriately and sheeting was performed, and the 24-hour period was It was left to mature at room temperature.

[0032]Combination No. For 2, 3, 4 and 5, J
Run the SR 230S three times with the cooling water faucet fully open and the roll gap fully tightened.
After mastication was continued for about 15 minutes with the roll gap set to 1.2 on the scale, FZ7302 was added after waiting until the surface of the rubber became smooth to ensure sufficient dispersion (formulation N).
o. In the case of No. 3, silicone VS polymer was added little by little and kneaded without waiting for sufficient dispersion, and then US-A was added and kneaded. Perform 3/4 cuts 6 times on each side alternately every 30 seconds, wait for sufficient dispersion, set the roll gap appropriately, and perform sheeting.
It was left to mature at room temperature for 4 hours. After aging at room temperature, heating on a ripe roll at 140°C ± 5°C for about 30 minutes and waiting for sufficient melting and dispersion of FZ7302,
Perbutyl C was added using a cold roll, and 3/4 cuts were made again 6 times on each side, alternating every 30 seconds. After sufficient dispersion, the roll gap was set appropriately and sheeting was performed. It was left to mature at room temperature.

Test piece preparation conditions: The test piece preparation conditions are as shown below. Blend No. Tests were conducted on samples 1, 2, 3, 4, and 5 which were aged at room temperature for 24 hours after molding under the above conditions at 176° C. for 6 minutes (mold temperature) (no secondary vulcanization).

Test results: The test results are shown in Table 2.

[0035]

[Table 2]

As shown in the above test results, formulation No. 1
is NBR alone, and formulation No. 2, No. 3 is NBR
This is a case where a rubber composition is prepared using a compatibilizer and a silicone rubber, and No. 4 and no. 5 is a comparative example in which no compatibilizer was used. The use of the compatibilizer showed superior measured values in each test item, confirming the effectiveness of the compatibilizer.

(Example 2) Polybutadiene rubber (JSR
BR7), using compatibilizer 2 instead of compatibilizer 1, changing the amount of each rubber and compatibilizer 2,
An experiment similar to Example 1 was conducted.

The results are shown in Table 3.

[0039]

[Table 3]

(Example 3) In place of the acrylonitrile butadiene rubber in Example 1, ethylene-propylene rubber (
JSR EP57C), each rubber, compatibilizer 1
An experiment similar to Example 1 was conducted by changing the amount used.

The results are shown in Table 4.

[0042]

[Table 4]

(Example 4) In place of the acrylonitrile butadiene rubber of Example 1, styrene-butadiene rubber (
JSR SL556), compatibilizer 2 was used in place of compatibilizer 1, and the amounts of each rubber and compatibilizer 2 used were changed, and an experiment similar to Example 1 was conducted.

The results are shown in Table 5.

[0045]

[Table 5]

[0046]

Effects and Effects of the Invention In the present invention, since a rubber composition is prepared by kneading organic rubber and silicone rubber using a specific compatibilizing agent, the characteristics of each of organic rubber and silicone rubber (organic Rubber tensile strength, tear strength,
It has unprecedented properties that have never been seen before, such as oil resistance, acid resistance, gas retention, and silicone rubber's heat resistance, weather resistance, ozone resistance, and cold resistance. The rubber composition of the invention can be used in many fields of application, such as electronic parts, mechanical parts, medical supplies, daily necessities, sports goods, leisure goods, health goods, civil engineering and construction goods, agricultural goods, chemical plant goods, and transportation equipment goods.

Claims (3)

[Claims] Claim 1: In producing a rubber composition by heating and kneading an organic rubber and a silicone rubber, 100 parts by weight of an ethylene polymer and the formula (A) R1 are used as a compatibilizer.
a R2 b SiO4 - a - b / 2
(A) (wherein R1 is an aliphatic unsaturated group, R2 is an unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated group,
A kneaded product having a gel content of 5 to 25% obtained by heating and kneading 50 to 250 parts by weight of an organopolysiloxane represented by 0 < a < 1, 0.5 < b < 3, 1 < a + b < 3). A method for producing a rubber composition, characterized in that it is used. 2. The method for producing a rubber composition according to claim 1, characterized in that 1.5 to 30 parts by weight of the compatibilizer is used per 100 parts by weight of the total amount of organic rubber and silicone rubber. 3. A rubber composition produced by the production method according to claim 1.