JP4922886B2 - Anti-vibration rubber composition and anti-vibration rubber using the same - Google Patents

Description

  The present invention relates to an anti-vibration rubber composition and an anti-vibration rubber using the anti-vibration rubber composition, and more particularly, to an engine mount, suspension bush, cab mount, etc. for suppressing vibration support of an engine such as an automobile. The present invention relates to an anti-vibration rubber composition used and an anti-vibration rubber using the same.

  In general, an anti-vibration rubber made of an anti-vibration rubber composition is used for a support function of an engine such as an automobile and an engine mount for suppressing vibration transmission. In order to improve the anti-vibration performance, it is effective to reduce the value of dynamic magnification [dynamic spring constant (Kd) / static spring constant (Ks)] (lower dynamic magnification), and to improve the support function. In order to satisfy, a certain degree of elasticity (static spring constant) is required. These characteristics are controlled mainly by adjusting the amount of carbon black added. Increasing the amount of carbon black added is effective in increasing the static spring constant and satisfying the support function. However, an increase in the amount of carbon black added not only increases the static spring constant but also affects the dynamic spring constant, particularly the latter. As a result, the increase of the dynamic spring constant becomes larger than the increase of the static spring constant, eventually the dynamic magnification becomes high and it is difficult to achieve a low dynamic magnification.

By the way, a butyl rubber composition is conventionally used for the vibration-proof rubber composition (see Patent Document 1).
Japanese Patent Laid-Open No. 3-126742

  However, since butyl rubber inherently does not have good compression set, it impedes the maintenance of the shape of the anti-vibration rubber, so that its use as an anti-vibration rubber is often limited. Conventionally, it has been adapted to improve the compression set by changing the cross-linking form. However, in this correspondence, other physical properties may be lowered. Therefore, an improvement is demanded in order to obtain an excellent compression set without causing such deterioration of physical properties.

  The present invention has been made in view of such circumstances, and in a butyl-based vibration-proof rubber composition, a vibration-proof rubber composition in which the compression set is improved without causing deterioration of physical properties and a vibration-proof using the same. The purpose is to provide vibration rubber.

In order to achieve the above object, the first gist of the present invention is an anti-vibration rubber composition having the following components (A) to (D) as essential components. Moreover, this invention makes the anti-vibration rubber | gum using the said anti-vibration rubber composition the 2nd summary.
(A) Halogenated butyl rubber.
(B) An azo initiator comprising a polycondensate of 4,4′-azobis (4-cyanovaleric acid) and polyethylene glycol.
(C) Carbon black.
(D) Alkylphenol disulfide.

  That is, the present inventors have made extensive studies to improve compression set without deteriorating physical properties in butyl-based vibration-proof rubber compositions. As a result, the inventors have found that the intended purpose can be achieved when a specific azo initiator and carbon black are used in combination with halogenated butyl rubber, and further, when alkylphenol disulfide is used as a vulcanizing agent, the present invention has been achieved.

  The reason why such a phenomenon occurs is not clear, but can be considered as follows. That is, since the specific azo initiator generates radicals and reacts with a polymer of halogenated butyl rubber or carbon black, it takes a crosslinked form as shown in FIG. 1 [in the figure, 1 is a polymer (molecular chain of rubber ) 2 represents an azo initiator, 3 represents carbon black, and 4 represents a cross-linked portion by a vulcanizing agent. ]. Then, as shown in the figure, the polymer 1 is partially physically crosslinked through the carbon black 3, so that it is considered that the polymer 1 is reinforced and the compression set is improved. Furthermore, since the radical generated by the azo initiator 2 is trapped in the carbon black 3 by this cross-linking mode, it prevents the carbon black 3 from being newly polymer-bonded even when heat is applied during compression. It may be possible.

  Thus, the anti-vibration rubber composition of the present invention is a combination of a halogenated butyl rubber and a specific azo initiator, carbon black, and alkylphenol disulfide. Therefore, in the butyl rubber vibration isolator composition, compression set can be improved without causing a decrease in physical properties. The anti-vibration rubber composition of the present invention can be advantageously used particularly for applications of anti-vibration rubber for vehicles such as automobiles, such as engine mounts, suspension bushings, and cab mounts.

  In particular, when the content ratio of the specific azo initiator is set in the range of 0.2 to 10 parts by weight with respect to 100 parts by weight of the halogenated butyl rubber, the effect of reducing the dynamic magnification can be obtained more.

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

  The anti-vibration rubber composition of the present invention is obtained using a halogenated butyl rubber (component A), a specific azo initiator (component B), carbon black (component C), and alkylphenol disulfide (component D). Can do.

  As the A component halogenated butyl rubber, chlorinated butyl rubber (Cl-IIR) or brominated butyl rubber (Br-IIR) is preferably used. These halogenated butyl rubbers are used alone or in combination of two or more.

  As the B component azo initiator, an azo initiator composed of a polycondensate of 4,4′-azobis (4-cyanovaleric acid) and polyethylene glycol is used. This azo initiator is represented, for example, by the following general formula (1).

  In the said General formula (1), m is the range of 30-150, and n is the range of 5-14. The azo initiator of the component B is preferably a polymer azo initiator having a number average molecular weight (Mn) in the range of 6000 to 100,000, more preferably in the range of number average molecular weight (Mn) 15000 to 40000. Is. That is, those having a number average molecular weight can suitably obtain an affinity with a polymer (halogenated butyl rubber). Examples of such azo initiators include commercially available products such as VPE-0201 and VPE-0601 manufactured by Wako Pure Chemical Industries.

  The blending amount of the azo initiator (component B) is preferably set in the range of 0.2 to 10 parts with respect to 100 parts by weight (hereinafter abbreviated as “part”) of the halogenated butyl rubber (component A). More preferably, it is the range of 1.0-5.0 parts. That is, if it is within this range, the effect of reducing the dynamic magnification can be obtained more. If the amount of the azo initiator (component B) is less than the lower limit, the effect of reducing the dynamic magnification by the azo initiator is insufficient. Conversely, when the blending amount of the azo initiator (component B) exceeds the upper limit, the effect of improving the low dynamic magnification cannot be obtained any more.

  Examples of the carbon black of component C include various grades of carbon black such as SAF class, ISAF class, HAF class, MAF class, FEF class, GPF class, SRF class, FT class, and MT class. These may be used alone or in combination of two or more. Among these, FEF grade carbon black is preferably used from the viewpoints of cost, durability, and the like.

  The blending amount of the carbon black (component C) is preferably set in the range of 0.2 to 10 parts, more preferably in the range of 1 to 5 parts with respect to 100 parts of the halogenated butyl rubber (component A). It is. That is, if the blending amount of the carbon black (C component) is less than the lower limit, the reaction between the polymer azo initiator and the carbon black becomes insufficient, and conversely, the blending of the carbon black (C component). This is because if the amount exceeds the upper limit, the viscosity increases and problems such as deterioration of workability occur.

  Examples of the D component alkylphenol disulfide include those in which the alkyl group is an amyl group or the like. These alkylphenol disulfides are used alone or in combination of two or more.

  The amount of the alkylphenol disulfide (component D) is preferably set in the range of 0.1 to 10 parts, more preferably in the range of 3 to 5 parts, with respect to 100 parts of the halogenated butyl rubber (component A). It is. That is, when the amount of the alkylphenol disulfide (D component) is less than the lower limit, the crosslinking reactivity tends to be deteriorated. Conversely, when the amount of the alkylphenol disulfide (D component) is too large, rubber properties (breaking This is because there is a tendency for the strength and elongation at break to decrease.

  In the anti-vibration rubber composition of the present invention, a vulcanization accelerator, a vulcanization aid, an anti-aging agent, stearic acid, process oil, and the like are appropriately blended together with the components A to D 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, a sulfenamide-based vulcanization accelerator is preferable from the viewpoint of excellent crosslinking reactivity.

  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 halogenated butyl 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 vulcanization aid include 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 halogenated butyl 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 halogenated butyl 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.

  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 halogenated butyl rubber (component A).

  The anti-vibration rubber composition of the present invention can be prepared, for example, as follows. That is, the halogenated butyl rubber (component A), a specific azo initiator (component B), carbon black (component C), and a vulcanization aid, anti-aging agent, process oil, etc., as necessary. These are blended and kneaded for about 3 to 5 minutes at 100 to 130 ° C. using a Banbury mixer or the like. 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. Make it. Next, the intended anti-vibration rubber can be obtained by vulcanizing the obtained anti-vibration rubber composition at a high temperature (150 to 170 ° C.) for 5 to 30 minutes.

  The anti-vibration rubber composition of the present invention is suitably used as an anti-vibration material for engine mounts, suspension bushings, cab mounts and the like used in, for example, automobile vehicles.

  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.

[Chlorinated butyl rubber (Cl-IIR)]
Chlorobutyl 1066, manufactured by JSR

[Brominated butyl rubber (Br-IIR)]
Bromobutyl 2244, manufactured by JSR

[Zinc oxide]
Two types of zinc oxide, manufactured by Sakai Chemical Industry Co., Ltd.

〔stearic acid〕
Lunac S30, manufactured by Kao

[Anti-aging agent]
NOCRACK 6C, manufactured by Ouchi Shinsei Chemical Co., Ltd.

〔Carbon black〕
FEF grade carbon black, seast SO, manufactured by Tokai Carbon

[Aroma oil]
Futsukoraromax # 1, manufactured by Fuji Kosan Co., Ltd.

[Azo initiator A]
VPE-0201 (number average molecular weight: about 15000-30000), manufactured by Wako Pure Chemical Industries, Ltd.

[Azo initiator B]
VPE-0601 (number average molecular weight: about 25000-40000), manufactured by Wako Pure Chemical Industries, Ltd.

[Vulcanization accelerator]
Noxeller CZ-G, manufactured by Ouchi Shinsei Chemical Co., Ltd.

[Alkylphenol disulfide]
TAKIROLL AP, manufactured by Taoka Chemical Co., Ltd.

[Example 1]
100 parts of Br-IIR, 1.0 part of azo initiator A, 33 parts of carbon black, 5 parts of zinc oxide as a vulcanization aid, 1 part of stearic acid as a vulcanization aid, and an antioxidant 3 parts and 3 parts of aroma oil were blended and kneaded for 4 minutes at 100 to 130 ° C. using a Banbury mixer. Next, 4.0 parts of a vulcanizing agent (alkylphenol disulfide) and 1.0 part of a vulcanization accelerator were blended into this, and kneaded at about 50 ° C. for 4 minutes using an open roll, thereby preventing A vibration rubber composition was prepared.

[Examples 2-8, Comparative Examples 1-2]
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 2 below.

[Permanent elongation]
A sheet made of the above rubber composition is vulcanized to a thickness of 2.0 ± 0.2 mm, punched into a shape conforming to JIS K 6273, according to JIS K 6273, temperature 100 ° C., test time 22 hours, elongation rate Permanent elongation was measured under the condition of 50%.

(Compression set)
A sheet made of the above rubber composition is molded into a shape and size conforming to JIS K 6262 to produce a vulcanized rubber test piece. According to JIS K 6262, the temperature is 85 ° C., the test time is 72 hours, and the compression rate is 25%. Under conditions, compression set was measured (condition i). The compression set was also measured under conditions of a temperature of 85 ° C., a test time of 240 hours, and a compression rate of 25% (condition ii).

  From the above results, the example products are excellent in permanent elongation, and the compression set is improved in both conditions i and ii. Moreover, since the improvement effect also depends on the addition amount, it can be seen that the improvement effect is due to the addition of the azo initiator. On the other hand, the comparative example product does not contain an azo initiator, and is found to be inferior in permanent elongation and compression set as compared with the example product.

  The anti-vibration rubber composition of the present invention is suitably used as an anti-vibration material for engine mounts, stabilizer bushes, suspension bushes and the like used in automobile vehicles.

It is a schematic diagram which shows the crosslinked form of rubber | gum.

Claims (5)

An anti-vibration rubber composition comprising the following (A) to (D) as essential components.
(A) Halogenated butyl rubber.
(B) An azo initiator comprising a polycondensate of 4,4′-azobis (4-cyanovaleric acid) and polyethylene glycol.
(C) Carbon black.
(D) Alkylphenol disulfide.   The anti-vibration rubber composition according to claim 1, wherein the halogenated butyl rubber as the component (A) is at least one of chlorinated butyl rubber (Cl-IIR) and brominated butyl rubber (Br-IIR).   The anti-vibration rubber composition according to claim 1 or 2, wherein the azo initiator of the component (B) is a polymer azo initiator having a number average molecular weight (Mn) in the range of 6000 to 100,000.   The content ratio of the azo initiator of the component (B) is set in a range of 0.2 to 10 parts by weight with respect to 100 parts by weight of the halogenated butyl rubber of the component (A). Anti-vibration rubber composition according to claim 1.   An anti-vibration rubber comprising the anti-vibration rubber composition according to any one of claims 1 to 4.

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