JP2008163067A - Rubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition satisfying both of good bonding property and ozone resistance by improving its ozone resistance and also preventing the reduction of the bonding property as much as possible. <P>SOLUTION: This rubber composition is characterized by containing at least 1 kind of natural rubber and a synthetic diene-based rubber, an amine-based anti-aging agent and silica gel, and also having 3 to 10 pts.mass content of the amine-based antioxidant based on 100 pts.mass rubber component. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rubber composition suitably used as a vibration-proof rubber for automobiles and the like.

  Various anti-vibration devices and anti-vibration members are used in automobiles and other vehicles, and rubber materials are often used for these anti-vibration devices and anti-vibration members. Conventionally, they are used as such anti-vibration rubbers. The rubber composition is prepared by adding various fillers, vulcanizing agents, vulcanization accelerators, anti-aging agents and the like to the rubber components of natural rubber and synthetic rubber (Patent Document 1).

  Such a rubber composition has a problem that the rubber surface is roughened by contact with ozone in the atmosphere, and durability as a vibration-proof rubber is deteriorated. The ozone resistance can be improved by adding excessive carbon black or increasing the amount of anti-aging agent. However, adding a large amount of carbon black or increasing the amount of anti-aging agent in this way can increase the resistance to steel and aluminum. Adhesiveness with a base material such as a material is lowered, which causes trouble when incorporated in a vibration isolator or when used as it is as a vibration isolator.

JP 2006-131871 A

  The present invention has been made in view of the above circumstances, and improves ozone resistance and prevents deterioration of adhesion as much as possible to achieve both good adhesion and ozone resistance. An object of the present invention is to provide a rubber composition that is suitably used as a rubber member or the like that is used by adhering to a base material such as steel or aluminum like rubber.

  As a result of intensive studies to achieve the above object, the present inventor has added a suitable amount of silica gel in a rubber composition in which an amine anti-aging agent is added as an additive to natural rubber or synthetic diene rubber. By improving the ozone resistance, it is possible to improve the ozone resistance satisfactorily without reducing the adhesion to steel and aluminum materials even if the amount of the amine-based anti-aging agent is increased. I found it.

  That is, conventionally, the addition amount of the amine-based anti-aging agent is about 0.5 to 2 parts by mass with respect to 100 parts by mass of the rubber component. For example, by adding and blending 5 to 100 parts by mass with respect to 100 parts by mass of the rubber component, the base component of the amine-based anti-aging agent is adsorbed by the acidic component of the silica gel, and the migration of the anti-aging agent to the adhesion interface is prevented. In addition, even if the addition amount of the amine-based anti-aging agent is increased to 3 parts by mass or more which has not been conventionally performed, ozone resistance is maintained while maintaining sufficient adhesiveness with steel and aluminum materials without reducing adhesiveness. The present invention has been completed by finding that the properties can be effectively improved.

  Therefore, the present invention contains at least one rubber component selected from natural rubber and synthetic diene rubber, an amine anti-aging agent, and silica gel, and the content of the amine anti-aging agent is the above. The rubber composition is provided in an amount of 3 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

  According to the present invention, the ozone resistance can be greatly improved by increasing the amount of the above-mentioned amine-based anti-aging agent, and good adhesiveness can be obtained without causing a decrease in adhesiveness due to the increase in the amount of the anti-aging agent. There is provided a rubber composition that is excellent in ozone resistance and has good adhesion to steel, aluminum, and the like, and is suitably used as a vibration-proof rubber.

Hereinafter, the present invention will be described in more detail.
As described above, the rubber composition of the present invention contains at least one rubber component selected from natural rubber and synthetic diene rubber, an amine antioxidant, and silica gel.

  More specifically, the rubber component includes natural rubber, butadiene rubber (BR), styrene butadiene rubber (SBR), butadiene-acrylonitrile copolymer rubber (NBR), isoprene rubber (IR), and isobutylene-isoprene. Synthetic diene rubbers such as polymer rubber (IIR) and chloroprene rubber (CR) are exemplified, and one or two or more of these may be used in combination. In some cases, one or two or more of these may be used. Other rubbers such as ethylene-propylene-diene copolymer (EPDM), acrylic rubber (ACM), and chlorosulfonated polyethylene (CSM) can be further mixed and used. Although not particularly limited, SBR, BR and IR are particularly preferably used among the synthetic diene rubbers.

  As said amine type | system | group antioxidant, a diallylamine type | system | group antioxidant and p-phenylenediamine type | system | group antioxidant are used preferably, These 1 type (s) or 2 or more types can be used together. More specifically, examples of these antiaging agents include p, p'-dioctyldiphenylamine, p, p'-dicumyldiphenylamine and the like as diallylamine antiaging agents, and examples of p-phenylenediamine antiaging agents. N, N′-diphenyl-p-phenylenediamine, N-phenyl-N′-isopropyl-p-phenylenediamine, N-phenyl-N′-1,3-dimethylbutyl-p-phenylenediamine, N-phenyl-N Examples include '-(3-methacryloyloxy-2-hydroxypropyl) -p-phenylenediamine. Among these, N-phenyl-N′-isopropyl-p-phenylenediamine and N-phenyl-N′-1,3-dimethylbutyl-p-phenylenediamine are particularly preferably used.

  The compounding amount of these amine anti-aging agents is 3 to 10 parts by mass, preferably 5 to 10 parts by mass with respect to 100 parts by mass of the rubber component. The amount of the agent is greatly increased to greatly improve the ozone resistance. In this case, if the compounding amount of the amine-based anti-aging agent is less than 3 parts by weight, sufficient ozone resistance cannot be obtained, and the object of the present invention cannot be sufficiently achieved. In some cases, the decrease in adhesiveness cannot be sufficiently prevented, and even when added in an amount exceeding 10 parts by mass, no particular improvement in effect is observed.

Next, the silica gel is not particularly limited, but the nitrogen adsorption specific surface area by the BET method is preferably 30 to 240 m ² / g, particularly 80 to 230 m ² / g. The base component of the amine anti-aging agent is adsorbed by the acidic component of the silica gel to prevent the amine anti-aging agent from migrating to the adhesive interface, and the amount of the amine anti-aging agent can be increased without causing a decrease in adhesion. It is a thing. In addition, when the specific surface area exceeds 240 m ² / g, the vibration isolation characteristics may be deteriorated.

  The compounding amount of the silica gel is not particularly limited, but is preferably 5 to 100 parts by mass, particularly 10 to 50 parts by mass with respect to 100 parts by mass of the rubber component. In this case, if the blending amount of silica gel is less than 5 parts by mass, a sufficient effect of preventing adhesion deterioration may not be obtained, and it becomes unsuitable when the static spring constant is lowered to obtain a vibration-proof rubber. There is a case. On the other hand, when the amount exceeds 100 parts by mass, it may be difficult to knead the composition into rubber.

  In addition to the above-mentioned components, the rubber composition of the present invention includes a vulcanizing agent, a vulcanization accelerator, a heat-resistant anti-aging agent, a wax, a colorant, a filler, a plasticizer, a softening agent, and tackifying as necessary. A known additive such as an agent can be appropriately added and blended.

  Examples of the vulcanizing agent include sulfur. Examples of the vulcanizing accelerator include 2-mercaptobenzothiazole, dibenzothiazyl disulfide, N-cyclohexyl-2-benzothiazylsulfenamide, and Nt-butyl. Benzothiazole vulcanization accelerators such as 2-benzothiazylsulfenamide and Nt-butyl-2-benzothiazylsulfenimide; guanidine vulcanization accelerators such as diphenylguanidine; tetradodecyl thiuram disulfide And thiouranium-based vulcanization accelerators such as tetraoctylthiouranium disulfide and tetrabenzylthiouranium disulfide; and other zinc dialkyldithiophosphates. Examples of the filler include carbon black, calcium carbonate, clay, mica and the like. Furthermore, known additives such as stearic acid and zinc white can be blended.

  The rubber composition of the present invention is produced by kneading the above components and heating as necessary. In this case, the kneading operation can use a conventionally known mixing device such as a roll, a Banbury mixer, a kneader or the like. Further, the molding can be appropriately selected according to the shape to be molded, the use of the molded product, such as press molding, transfer molding and main molding. Further, the rubber composition of the present invention has excellent ozone resistance and good adhesiveness, and is particularly suitable as a vibration-proof rubber used by being bonded to a base material made of steel or aluminum. In this case, the adhesive is not particularly limited, but a phenol resin adhesive, an epoxy adhesive, a hypalon adhesive, a chlorinated rubber adhesive, and the like are preferably used.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not restrict | limited to the following Example.

[Examples 1-7, Comparative Examples 1-3]
The following blending components shown in Table 1 were kneaded and vulcanized to obtain 10 types of rubber compositions of Examples 1 to 7 and Comparative Examples 1 to 3. About each obtained rubber composition, ozone resistance and adhesiveness were evaluated as follows. The results are shown in Table 1.

Ozone resistance In accordance with JIS K6259 (1993), a dynamic ozone degradation test was conducted under the conditions of 40 ° C., 50 pphm, and 0-20% elongation. Evaluated according to.
Adhesiveness According to JIS K6256 (1999), a peel test was performed on steel and aluminum materials to evaluate the adhesiveness. In the pass / fail judgment, the case where the rubber cohesive failure occurred was evaluated as ◯ (good), and the case where the other failure occurred was evaluated as x (failed). The values of “After heat aging” in Table 1 are the results after leaving at 70 ° C. for 1000 hours.

ＲＳＳ＃１
天然ゴム Ribbed smoked Sheet １号
Nipsil VN3
沈降式シリカ、ＢＥＴ比表面積１８０〜２３０ｍ²／ｇ（東ソー・シリカ（株）製）
６ＰＰＤ(6C)
大内新興化学工業社製の老化防止剤（Ｎ−フェニル−Ｎ’−１，３−ジメチルブチル−ｐ−フェニレンジアミン）
１ＰＰＤ(3C)
大内新興化学工業社製の老化防止剤（Ｎ−フェニル−Ｎ’−イソプロピル−ｐ−フェニレンジアミン）
ＲＤ
耐熱老化防止剤（大内新興化学工業社製）
ＣＺ
加硫促進剤（大内新興化学工業社製）

RSS # 1
Natural rubber Ribbed smoked Sheet No.1
Nipsil VN3
Precipitated silica, BET specific surface area 180-230 m ² / g (manufactured by Tosoh Silica Co., Ltd.)
6PPD (6C)
Anti-aging agent (N-phenyl-N′-1,3-dimethylbutyl-p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Co., Ltd.
1PPD (3C)
Anti-aging agent (N-phenyl-N'-isopropyl-p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Co., Ltd.
RD
Heat aging inhibitor (manufactured by Ouchi Shinsei Chemical Co., Ltd.)
CZ
Vulcanization accelerator (Ouchi Shinsei Chemical Co., Ltd.)

  As shown in Table 1, the rubber compositions of the examples to which 3 parts by mass or more, particularly 5 parts by mass or more of the amine-based anti-aging agent (6PPD, 1PPD) are added are excellent in ozone resistance, and moreover the silica gel (Nipsil VN3). By blending, it has good adhesion to steel and aluminum. On the other hand, the rubber compositions of Comparative Examples 2 and 3 having a small compounding amount of the amine anti-aging agent of 1 part by mass are poor in ozone resistance but 5% of the amine anti-aging agent although the adhesiveness is good. Although the rubber composition of Comparative Example 1 increased in mass parts is excellent in ozone resistance, since the silica gel is not blended, the adhesiveness is greatly lowered.

  Thus, the ozone resistance can be greatly improved by increasing the amount of the amine-based anti-aging agent, and good adhesion can be achieved without causing a decrease in the adhesiveness due to the increase in the amount of the anti-aging agent by adding silica gel. It was confirmed that a rubber composition having

Claims (7)

  It contains at least one rubber component of natural rubber and synthetic diene rubber, an amine anti-aging agent and silica gel, and the content of the amine anti-aging agent is 3 with respect to 100 parts by mass of the rubber component. A rubber composition characterized in that the content is from 10 to 10 parts by mass.   The rubber composition according to claim 1, comprising a diallylamine-based antioxidant and / or a p-phenylenediamine-based antioxidant as the amine-based antioxidant.   The rubber composition according to claim 1 or 2, wherein the content of the amine-based antioxidant is 5 to 10 parts by mass with respect to 100 parts by mass of the rubber component.   The rubber composition according to claim 1, comprising one or more selected from styrene butadiene rubber, butadiene rubber and isoprene rubber as the synthetic diene rubber. The rubber composition according to any one of claims 1 to 4, wherein the silica gel is a silica gel having a nitrogen adsorption specific surface area of 30 to 240 m ² / g by a BET method.   The rubber composition according to any one of claims 1 to 5, wherein the content of silica gel is 5 to 100 parts by mass with respect to 100 parts by mass of the rubber component.   The rubber composition according to any one of claims 1 to 6, which is used as a vibration-proof rubber.