JP6383624B2 - Anti-vibration rubber composition - Google Patents

Description

  The present invention relates to an anti-vibration rubber composition used for vehicles such as automobiles and trains, and more particularly, to support functions for engines of automobiles and the like and to be used for engine mounts for suppressing vibration transmission. The present invention relates to a vibration rubber composition.

  In general, an anti-vibration rubber composition is used in automobiles for the purpose of reducing vibration and noise. Conventionally, various rubbers have been used as the above-mentioned vibration-proof rubber polymer. Among them, natural rubber (NR) is inexpensive and excellent in vibration-proof characteristics, and thus is frequently used.

  The above natural rubber is vulcanized with sulfur. In conventional sulfur vulcanization, the amount of sulfur and the type and amount of vulcanization accelerator are adjusted to control the form of crosslinking such as monosulfide and polysulfide. In addition, high heat resistance and high durability of the vibration-proof rubber are realized (for example, see Patent Document 1).

Japanese Patent No. 5568493

  However, in the crosslinked form in sulfur vulcanization, the monosulfide form has a problem that the durability is lowered because the bond energy is high and the heat resistance is excellent but the flexibility is low. On the other hand, the polysulfide form has high flexibility and excellent durability, but has a problem that the binding energy is low and the heat resistance is lowered.

  Thus, in the conventional sulfur vulcanization, there is a problem that heat resistance and durability are in a trade-off relationship and it is difficult to achieve both.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a vibration-insulating rubber composition that is a sulfur-crosslinking rubber composition that has excellent heat resistance and durability. .

In order to achieve the above object, an anti-vibration rubber composition of the present invention is an anti-vibration rubber composition containing the following (B) component together with the following (A) component, and comprises (A) component 100: The amount of component (B) is in the range of 0.1 to 10 parts by weight with respect to parts by weight.
(A) Diene rubber.
(B) Consists of 1,4,5,6-oxatrithiocan, 1,4,5,6,7-oxatetrathionan, 1,2,3-trithiepane, and 1,2,3,4-trithiocan At least one cyclic polysulfide compound selected from the group ;

This inventor repeated earnest research in order to solve the said subject. In the course of the research, the present inventor found that, in the crosslinked form of the sulfur bridge, when the specific gravity is placed on the monosulfide form, the SS bond is small, so that the heat resistance is good, but the crosslinked chain is short, so the flexibility is high. And the knowledge that the durability is deteriorated was obtained. In addition, if the specific gravity is placed on the polysulfide form, the cross-linked chain becomes longer, so that the flexibility is improved and the durability is improved. However, since there are many SS bonds, the bonds are easily broken when heated, and the heat resistance is poor. I got the knowledge that it will be. In order to solve such a problem of sulfur cross-linking, the present inventor repeated further experiments. As a result, the specific cyclic polysulfide compound (B) is used as a cross-linking agent for diene rubber (natural rubber, etc.) for a specific amount. As a result, it was found that the intended purpose could be achieved, and the present invention was achieved.

That is, the above-mentioned specific cyclic polysulfide compound (B) is ring-opened at the S—S bond portion having a low binding energy by heating, and forms a crosslinked structure while exhibiting good reactivity with the diene rubber. For example, when 1,4,5,6-oxatrithiocan (OTTC) is used as the cyclic polysulfide compound, the crosslinked chain formed by such ring-opening crosslinking is -S-C-C-O- It becomes a cross-linked chain of C—C—S—. As described above, since the cross-linked chain is moderately long, it is possible to impart appropriate flexibility and enhance durability, and at the same time, the cross-linked chain has almost no SS structure, and thus has excellent heat resistance. It becomes like this. Thus, in this invention, it is thought that heat resistance and durability were made compatible by the use of the specific cyclic polysulfide compound (B) .

Thus, vibration damping rubber composition of the present invention, together with the diene rubber (A component), those obtained by the particular amount above specific cyclic polysulfide compound (B component). Therefore, the anti-vibration rubber composition of the present invention has excellent heat resistance and excellent durability. The anti-vibration rubber composition of the present invention is an anti-vibration rubber member that is required to have heat resistance and durability, such as an engine mount, a stabilizer bush, a suspension bush, etc. used in an automobile vehicle, a building / house, etc. It can be suitably used as a material for a vibration-proof rubber member in the field.

  Next, embodiments of the present invention will be described in detail.

  The anti-vibration rubber composition of the present invention is obtained by blending a diene rubber (component A) and a specific crosslinking agent (vulcanizing agent) (component B), and the blending amount is within a specific range. Is set to

  Examples of the diene rubber (component A) include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), and ethylene-propylene-diene rubber (EPDM). Is given. These may be used alone or in combination of two or more.

Next, in the present invention, a specific cyclic polysulfide compound (B component) is used as a crosslinking agent (vulcanizing agent) used together with the diene rubber (A component).

As the specific cyclic polysulfide compound (component B), specifically, 1,4,5,6-oxatrithiocan (OTTC) represented by the following chemical formula (1-1), the following chemical formula (1-2) 1,4,5,6,7-oxatetrathionan shown below, 1,2,3-trithiepan shown in the following chemical formula (1-3), 1,2,3 shown in the following chemical formula (1-4) , 4-trithiocane is used . And these are used individually or in combination of 2 or more types. Among these, OTTC is preferable because it is more excellent in the balance between heat resistance and durability.

And the compounding quantity of the said specific cyclic polysulfide compound (B component) is 0.1-10 parts with respect to 100 weight part (henceforth "part") of the said diene rubber (A component). is there. Preferably, it is the range of 0.5-5 parts. That is, if the blending amount is too small, a sufficient cross-linked structure cannot be obtained, and desired durability cannot be obtained. Conversely, if the blending amount is too large, desired heat resistance and the like can be obtained. Because it disappears.

  In the anti-vibration rubber composition of the present invention, a vulcanization accelerator, a reinforcing agent, a vulcanization aid, an anti-aging agent, a process oil and the like are appropriately blended with the A and B components as necessary. Is also possible.

  Examples of the vulcanization accelerator include vulcanization accelerators such as thiazole, sulfenamide, thiuram, aldehyde ammonia, aldehyde amine, guanidine, and thiourea. These may be used alone or in combination of two or more. Among these, it is preferable to add a sulfenamide-based vulcanization accelerator because the interaction with the cyclic polysulfide compound (component B) is more excellent in the balance between heat resistance and durability.

  The blending amount of the vulcanization accelerator is preferably in the range of 0.5 to 7 parts, particularly preferably in the range of 0.5 to 5 parts with respect to 100 parts of the diene rubber (component A). .

  Examples of the thiazole vulcanization accelerator include dibenzothiazyl disulfide (MBTS), 2-mercaptobenzothiazole (MBT), 2-mercaptobenzothiazole sodium salt (NaMBT), and 2-mercaptobenzothiazole zinc salt (ZnMBT). Etc. These may be used alone or in combination of two or more. Among these, dibenzothiazyl disulfide (MBTS) and 2-mercaptobenzothiazole (MBT) are preferably used because they are particularly excellent in crosslinking reactivity.

  Examples of the sulfenamide-based vulcanization accelerator include N-oxydiethylene-2-benzothiazolylsulfenamide (NOBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), and Nt. -Butyl-2-benzothiazoylsulfenamide (BBS), N, N'-dicyclohexyl-2-benzothiazoylsulfenamide and the like.

  Examples of the thiuram vulcanization accelerator include tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), tetrakis (2-ethylhexyl) thiuram disulfide (TOT), and tetrabenzylthiuram. Examples thereof include disulfide (TBzTD).

  Examples of the reinforcing agent include carbon black, silica, talc and the like. These may be used alone or in combination of two or more.

  The compounding amount of the reinforcing agent is preferably in the range of 10 to 100 parts, particularly preferably in the range of 20 to 70 parts, with respect to 100 parts of the diene rubber (component A). That is, if the blending amount is too small, a certain level of reinforcing properties cannot be satisfied. Conversely, if the blending amount is too large, the dynamic magnification becomes high, the viscosity increases, and the workability deteriorates. This is because there arises a problem such as.

  Examples of the vulcanization aid include zinc oxide, zinc white (ZnO), stearic acid, magnesium oxide and the like. These may be used alone or in combination of two or more.

  The amount of the vulcanization aid is preferably in the range of 1 to 25 parts, particularly preferably in the range of 3 to 10 parts, with respect to 100 parts of the diene rubber (component A).

  Examples of the anti-aging agent include carbamate-based anti-aging agents, phenylenediamine-based anti-aging agents, phenol-based anti-aging agents, diphenylamine-based anti-aging agents, quinoline-based anti-aging agents, imidazole-based anti-aging agents, and waxes. can give. These may be used alone or in combination of two or more.

  The blending amount of the anti-aging agent is preferably in the range of 1 to 10 parts, particularly preferably in the range of 2 to 5 parts with respect to 100 parts of the diene rubber (component A).

  Examples of the process oil include naphthenic oil, paraffinic oil, and aroma oil. These may be used alone or in combination of two or more.

  Further, the blending amount of the process oil is preferably in the range of 1 to 50 parts, particularly preferably in the range of 3 to 30 parts with respect to 100 parts of the diene rubber (component A).

  The anti-vibration rubber composition of the present invention can be prepared, for example, as follows. That is, the diene rubber (component A) and, if necessary, a reinforcing agent, an anti-aging agent, a process oil, a vulcanization aid, and the like are appropriately blended, and these are added using a Banbury mixer or the like. Kneading is started from a temperature of 50 ° C., and kneading is performed at 100 to 160 ° C. for about 3 to 5 minutes. Next, a vulcanizing agent, a vulcanization accelerator, and the like are appropriately blended in this, and kneaded using an open roll under predetermined conditions (for example, 50 ° C. × 4 minutes) to obtain a vibration-proof rubber composition. Can be prepared. Thereafter, the resulting anti-vibration rubber composition is vulcanized at a high temperature (150 to 170 ° C.) for 5 to 30 minutes to obtain an anti-vibration rubber (vulcanized body).

  By using the anti-vibration rubber composition of the present invention as described above as the material of the anti-vibration rubber, it is possible to obtain an effect that is excellent in heat resistance and durability. Therefore, the anti-vibration rubber composition of the present invention prepared as described above is an anti-vibration rubber member that is required to have heat resistance and durability, for example, an engine mount and a stabilizer bush used for automobile vehicles. It can be suitably used as a material for a suspension bush or the like, and a vibration-proof rubber member in the construction / housing field.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

First, prior to the examples and comparative examples, the following materials were prepared. In the vulcanizing agent described later, the weight ratio (%) of a mixture of a plurality of types of compounds was measured by gas chromatography under the following conditions and indicated.
Apparatus: Gas chromatograph (manufactured by SHIMADZU)
Carrier gas: He
Column: fused silica capillary column
Sample vaporization temperature 200 ℃
Set temperature: After holding at 40 ° C. for 7 minutes, the temperature is raised at 10 ° C./min and set to 250 ° C. Detector: Hydrogen flame ion detector (FID)
Sample preparation: 1 μl of sample is weighed with a microsyringe and measured.

[NR]
Natural rubber

[Zinc oxide]
2 types of zinc oxide, manufactured by Sakai Chemical Industry

〔stearic acid〕
LUNAC S30, manufactured by Kao

[Anti-aging agent]
Ozonon 6C, manufactured by Seiko Chemical Co., Ltd.

〔wax〕
Sunnock, Ouchi Shinsei Chemical Co., Ltd.

〔Carbon black〕
Seast SO, manufactured by Tokai Carbon

[Naphthenic oil]
Diana Process NM280, manufactured by Idemitsu Petrochemical Co., Ltd.

[Vulcanization accelerator CBS]
Noxeller CZ, Ouchi Shinsei Chemical Co., Ltd.

[Vulcanization accelerator TMTD]
Sunseller TT, Sanshin Chemical Co., Ltd.

[Vulcanizing agent ( I )]
OTTC (sample), manufactured by Sumitomo Seika Co., Ltd. {Vulcanizing agent mixed with multiple types of compounds. Ratio of 1,4,5,6-oxatrithiocan (OTTC) shown in chemical formula (a) below to the entire vulcanizing agent: 65%, 1,4,5-oxadithiepan shown in chemical formula (b) below Ratio: 20%, ratio of 1,4,5,6,7-oxatetrathionan shown in chemical formula (c) to be described later: 15%. }

[Vulcanizing agent ( II )]
A vulcanizing agent in which multiple types of compounds are mixed. The proportion of 1,2,3-trithiepan shown in the chemical formula (d) described later with respect to the entire vulcanizing agent: 75%, the proportion of 1,2-dithiane shown in the chemical formula (e) below with 15%, the chemical formula shown later Ratio of 1,2,3,4-trithiocan shown in (f): 10%.

[Vulcanizing agent ( III )]
A vulcanizing agent in which multiple types of compounds are mixed. The proportion of 1,2,3-trithiane shown in chemical formula (g) below: 65%, the proportion of 1,2-dithiolane shown in chemical formula (h) below: 23%, and the chemical formula below Ratio of 1,2,3,4-tetrathiepan shown in (i): 12%.

[Vulcanizing agent ( IV )]
Cyclic polysulfide compound represented by the following chemical formula (j)

[Example 1]
100 parts of NR, 5 parts of zinc oxide, 1 part of stearic acid, 1 part of anti-aging agent, 2 parts of wax, 50 parts of carbon black and 3 parts of naphthenic oil are blended, and these are mixed with a Banbury mixer. It knead | mixed for 5 minutes at 140 degreeC. Next, 2 parts of the vulcanizing agent ( I ) and 1 part of the vulcanization accelerator CBS were blended in this, and kneaded at 60 ° C. for 5 minutes using an open roll, whereby an anti-vibration rubber composition A product was prepared.

[Example 2, Comparative Examples 1-3]
As shown in Table 1 below, an anti-vibration rubber composition was prepared according to Example 1 except that the amount of each component was changed.

  Using the anti-vibration rubber compositions of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. The results are also shown in Table 1 below.

〔Heat-resistant〕
Each anti-vibration rubber composition was press-molded (vulcanized) under the conditions of 150 ° C. × 20 minutes to prepare a test piece. Subsequently, the elongation at break (EB) of the test piece was measured at a temperature of 25 ° C. according to JIS K 6251. Moreover, after the said test piece was heat-aged in 100 degreeC atmosphere for 500 hours, elongation at break (EB) was measured like the above. And the decreasing rate ((DELTA) EB) (%) of the elongation at break after heat aging with respect to the elongation at break of the test piece of the initial stage (before heat aging) was computed. As a result, a case where ΔEB was 10% or less was evaluated as “◎”, a case where ΔEB was larger than 10% and 30% or less was evaluated as “◯”, and a case where ΔEB was larger than 30% was evaluated as “X”.

〔durability〕
Using each anti-vibration rubber composition, press vulcanization at 150 ° C. for 20 minutes was performed to produce a rubber test piece of 120 mm × 120 mm × thickness 2 mm. Then, in accordance with JIS K 6270, using this rubber test piece, it was punched into a JIS-5 dumbbell, and in an environment at a temperature of 25 ° C., 0 to 100% elongation was repeated at 5 Hz until the dumbbell broke. And the number of stretching at break (number of breaks) was measured. And the measured value in the anti-vibration rubber composition of Example 1 is set to 100, and with respect to this value, the measured value in the anti-vibration rubber composition of each Example and Comparative Example is converted into an index. What was present was evaluated as “◎”, what was 70% or more and less than 100% was evaluated as “◯”, and what was less than 70% was evaluated as “x”.

  From the above results, it can be seen that the rubber compositions of the examples have excellent effects in both heat resistance and durability.

  On the other hand, although the rubber composition of Comparative Example 1 is excellent in heat resistance, the durability is greatly inferior. Although the rubber composition of Comparative Example 2 is excellent in durability, the heat resistance is greatly inferior. Although the rubber composition of Comparative Example 3 is excellent in heat resistance, the durability is greatly inferior.

  The anti-vibration rubber composition of the present invention is excellent in heat resistance and can have an effect excellent in durability. Therefore, the vibration-insulating rubber composition of the present invention is a vibration-insulating rubber member that is required to have heat resistance and durability, such as engine mounts, stabilizer bushes, suspension bushes, etc. used in automobile vehicles, etc. -It can use suitably as a material of the vibration proof rubber member in a housing field.

Claims (7)

An anti-vibration rubber composition containing the following component (B) together with the following component (A), wherein the blending amount of component (B) is 0.1 to 10 weights per 100 parts by weight of component (A) An anti-vibration rubber composition characterized by being in the range of parts.
(A) Diene rubber.
(B) Consists of 1,4,5,6-oxatrithiocan, 1,4,5,6,7-oxatetrathionan, 1,2,3-trithiepane, and 1,2,3,4-trithiocan At least one cyclic polysulfide compound selected from the group ; The cyclic polysulfide compound (B) is 1,4,5,6-oxa Bok Richioka emissions, claim 1 vibration damping rubber composition. The anti-vibration rubber composition according to claim 1 or 2, wherein 80% by weight or more of the cyclic polysulfide compound contained in the anti-vibration rubber composition is the cyclic polysulfide compound (B). The anti-vibration rubber composition according to any one of claims 1 to 3, wherein the vulcanizing agent contained in the anti-vibration rubber composition comprises a cyclic polysulfide compound. Furthermore, the anti-vibration rubber composition as described in any one of Claims 1-4 containing a sulfenamide type | system | group vulcanization accelerator. The sulfenamide vulcanization accelerator is N-oxydiethylene-2-benzothiazolylsulfenamide (NOBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), Nt-butyl- 2-benzothiazolyl sulfenamide (BBS), and N, at least one selected from the group consisting of N'- dicyclohexyl-2-benzothiazolyl sulfenamide, vibration damping rubber composition according to claim 5, wherein object. A vulcanized body of the vibration-proof rubber composition according to any one of claims 1 to 6 .