JP2008208204A - Vibration-proof rubber composition and vibration-proof rubber by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration-proof rubber composition capable of obtaining a more excellent low dynamic to static magnitude ratio effect than those of means examined until now. <P>SOLUTION: This vibration-proof rubber composition is provided by containing (A) a diene-based rubber, (B) 12-hydroxystearic acid. (C) carbon black and (D) stearic acid, and setting 0.5 pt.wt. to 20 pts.wt. range blended amount of the component (B) based on 100 pts.wt. component (A) and also setting ≤85 pts.wt. blended amount of the component (C) based on 100 pts.wt. component (A). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an anti-vibration rubber composition and an anti-vibration rubber using the anti-vibration rubber composition. The present invention relates to a composition and an anti-vibration rubber using the composition.

  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, an increase in the dynamic spring constant appears more markedly than an increase in the static spring constant, eventually increasing the dynamic magnification and making it difficult to achieve a low dynamic magnification.

  Thus, as a technique for reducing the dynamic magnification without increasing the amount of carbon black, a technique using a carbon black having a large particle diameter has been proposed. However, in the above method, the specific surface area (BET specific surface area) of the carbon black is small, the physical bonding force between the rubber and the carbon black or between the carbon blacks is lowered, and the durability of the vibration isolating rubber is deteriorated.

In order to solve this problem, for example, an anti-vibration rubber comprising a rubber member made of a rubber composition containing a diene rubber component, a specific hydrazine derivative, and a large particle size / high structure carbon black has been proposed. (Patent Document 1).
JP 2006-143859 A

  The anti-vibration rubber described in Patent Document 1 is intended to reduce the dynamic magnification by the combined use of large particle size / high structure carbon black and hydrazine, but the low dynamic magnification effect is not sufficient. However, there is room for improvement in order to obtain a further excellent low dynamic magnification effect.

  An object of the present invention is to provide an anti-vibration rubber composition capable of obtaining a low dynamic magnification effect superior to the techniques that have been studied so far, and an anti-vibration rubber using the same.

In order to achieve the above object, the present invention contains the following components (A) to (D), and the blending amount of the component (B) is 0.5 to 100 parts by weight of the component (A). The first aspect is an anti-vibration rubber composition which is set in the range of 20 parts by weight and the blending amount of the component (C) is set to 85 parts by weight or less with respect to 100 parts by weight of the component (A). . Moreover, this invention makes the 2nd summary the vibration proof rubber using the said vibration proof rubber composition.
(A) Diene rubber.
(B) 12-hydroxystearic acid.
(C) Carbon black.
(D) Stearic acid.

  That is, the present inventors have intensively studied in order to obtain an anti-vibration rubber composition capable of obtaining an excellent effect of reducing dynamic magnification. And it discovered that the outstanding low dynamic-velocity effect could be acquired by using 12-hydroxystearic acid and carbon black together by the predetermined compounding quantity, respectively, and reached | attained this invention. The reason for this is not clear, but can be considered as follows. That is, 12-hydroxystearic acid is shortened in the diene rubber, so that the diene rubber is reinforced, and the effect of increasing the static spring constant (Ks) is larger than that of carbon black. Since the effect on increasing the dynamic spring constant (Kd) is small, it is presumed that the low dynamic magnification effect was manifested.

  As described above, the vibration-proof rubber composition of the present invention uses 12-hydroxystearic acid and carbon black in combination with each other at a predetermined blending amount. A magnification effect can be obtained. The anti-vibration rubber composition of the present invention is used in accordance with the application of the anti-vibration rubber from a low static spring constant to a high static area, but in a high static spring constant area where a large amount of carbon black is blended. Also, an excellent low dynamic magnification effect can be exhibited. In addition, since the vibration-proof rubber composition of the present invention uses 12-hydroxystearic acid together with stearic acid as a vulcanization aid, compared to the case where only stearic acid is used, it has a lower dynamic magnification. Excellent effect is obtained.

  Further, when the blending amount of the carbon black (component C) is set in the range of 20 to 70 parts by weight with respect to 100 parts by weight of the diene rubber (component A), the effect of reducing the dynamic magnification is further improved.

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

  The anti-vibration rubber composition of the present invention is obtained using a diene rubber (component A), 12-hydroxystearic acid (component B), carbon black (component C), and stearic acid (component D). Can do.

  Here, in the present invention, the greatest feature is that the blending amounts of 12-hydroxystearic acid (component B) and carbon black (component C) are set within predetermined ranges.

  The diene rubber (component A) is not particularly limited. For example, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR). ), Ethylene-propylene-diene rubber (EPDM) and the like. These may be used alone or in combination of two or more. Among these, natural rubber is preferably used in terms of excellent vibration-proof performance.

Further, 12-hydroxystearic acid (component B) used together with the diene rubber (component A) has a hydroxyl group (—OH) at the 12-position of stearic acid [CH ₃ (CH ₂ ) ₁₆ COOH]. Good examples include those derived from castor oil.

  The blending amount of the 12-hydroxystearic acid (component B) needs to be set in the range of 0.5 to 20 parts with respect to 100 parts by weight (hereinafter referred to as “part”) of the diene rubber (component A). , Preferably in the range of 0.5 to 5 parts. That is, when the blending amount of the 12-hydroxystearic acid (component B) is less than the lower limit, the effect of reducing the dynamic magnification due to the reinforcing effect of 12-hydroxystearic acid is insufficient. This is because if the blending amount of component B) exceeds the upper limit, the dynamic magnification increases due to softening of the rubber and a decrease in the value of the static spring constant (Ks), resulting in poor vibration isolation performance.

  Next, the carbon black (C component) used together with the A component and the B component is not particularly limited. For example, SAF class, ISAF class, HAF class, MAF class, FEF class, GPF class, SRF class, FT There are various grades of carbon black such as grades and MT grades. 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 compounding amount of the carbon black (component C) needs to be set to 85 parts or less, preferably in the range of 20 to 70 parts, with respect to 100 parts of diene rubber (component A). That is, if the blending amount of the carbon black (component C) exceeds the upper limit, problems such as an increase in viscosity and deterioration of workability occur.

  The average particle size (primary particle size) of the carbon black (component C) is preferably in the range of 20 to 200 nm, particularly preferably in the range of 40 to 80 nm.

  The amount of stearic acid (component D) used together with the components A to C is preferably in the range of 0.5 to 5 parts, particularly preferably 1 to 100 parts per 100 parts of diene rubber (component A). The range is 3 parts. That is, if the amount of the stearic acid (D component) is too small, the dispersibility of the compounding agent tends to deteriorate, and if the amount of stearic acid (D component) is increased, the rubber is softened. It is expected that various problems will occur.

  In addition, in the vibration-proof rubber composition of the present invention, a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, an antiaging agent, a process oil, and the like are appropriately blended together with the components A to D as necessary. It is also possible.

  Examples of the vulcanizing agent include sulfur (powder sulfur, precipitated sulfur, insoluble sulfur) and the like. These may be used alone or in combination of two or more.

  The blending amount of the vulcanizing agent is preferably in the range of 0.3 to 7 parts, particularly preferably in the range of 1 to 5 parts with respect to 100 parts of the diene rubber (component A). That is, if the blending amount of the vulcanizing agent is too small, the crosslinking reactivity tends to be deteriorated. Conversely, if the blending amount of the vulcanizing agent is too large, the rubber properties (breaking strength, breaking elongation) are lowered. This is because there is a tendency.

  The vulcanization accelerator is not particularly limited, and examples thereof include thiazole series, sulfenamide series, thiuram series, aldehyde ammonia series, aldehyde amine series, guanidine series, and thiourea series vulcanization accelerators. 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 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).

  The vulcanization aid is not particularly limited, and examples thereof 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 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), a predetermined amount of 12-hydroxystearic acid (component B), a predetermined amount of carbon black (component C), and stearic acid (component D) are added as necessary. Sulfur aids, anti-aging agents, process oils and the like are appropriately blended, and these are kneaded at 100 to 130 ° C. for about 3 to 5 minutes 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, stabilizer bushes, suspension bushes and the like used in automobile vehicles, for example.

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

[Example 1]
100 parts of natural rubber which is a diene rubber (component A), 5 parts of zinc oxide which is a vulcanization aid, 1 part of stearic acid which is a vulcanization aid, 1 part of anti-aging agent, and 2 parts of wax , 20 parts of carbon black (component C), 5 parts of naphthenic oil, and 5 parts of 12-hydroxystearic acid (component B) are kneaded at 100 to 130 ° C. for 4 minutes using a Banbury mixer. went. Next, 2 parts of a vulcanizing agent (sulfur) and 1 part of a vulcanization accelerator were blended into this, and kneaded at about 50 ° C. for 4 minutes using an open roll, thereby producing a vibration-proof rubber composition. Prepared.

[Examples 2 to 8, Comparative Examples 1 to 10]
As shown in the following Tables 1 to 4, anti-vibration rubber compositions were prepared according to Example 1 except that the amount of each component was changed.

The materials shown in Tables 1 to 4 are as follows.
[Zinc oxide]
2 types of zinc oxide [stearic acid] manufactured by Sakai Chemical Industry Co., Ltd.
Lunac S30, made by Kao
[Anti-aging agent]
Nocrack 6C, manufactured by Ouchi Shinsei Chemical
〔wax〕
Sunnock (carbon black), manufactured by Ouchi Shinsei Chemical Co., Ltd.
FEF-grade carbon black (Cabot, N550)
[Naphthenic oil]
Idemitsu Kosan Co., Ltd., Diana Process NM-280
[Vulcanization accelerator]
Ouchi Shinsei Chemical Co., Ltd., Noxeller CZ
[12-hydroxystearic acid]
Made by Ito Oil

  Using the anti-vibration rubber compositions of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. The result was combined with said Table 1-Table 4, and was shown.

[Initial physical properties]
Each anti-vibration rubber composition was press-molded under the conditions of 150 ° C. × 20 minutes and punched with a JIS No. 5 dumbbell to prepare a rubber sheet having a thickness of 2 mm. Then, using this rubber sheet, the breaking strength (TS) and the breaking elongation (Eb) were measured in accordance with JIS K 6251.

(Dynamic characteristics)
(Static spring constant: Ks)
Using each anti-vibration rubber composition, press vulcanization under vulcanization conditions at 150 ° C. for 30 minutes to prepare a vulcanized rubber sample having a cylindrical shape (diameter 50 mm, height 25 mm), and then the vulcanized rubber sample A test piece was prepared by adhering a pair of disk-shaped metal fittings (diameter 60 mm, thickness 6 mm) to the upper and lower surfaces with an adhesive. Next, the test piece was compressed 7 mm in the cylinder axis direction, and the static spring constant (Ks) was calculated by reading the load at the time of deflection of 1.5 mm and 3.5 mm from the load deflection curve of the second round. .
(Dynamic spring constant: Kd100)
The test piece is compressed 2.5 mm in the direction of the cylinder axis, and a constant displacement harmonic compression vibration with an amplitude of 0.05 mm is applied at a frequency of 100 Hz from the bottom, centered on the position of this 2.5 mm compression, and moved by an upper load cell. The dynamic spring constant (Kd100) was calculated and measured according to JIS K 6394.
(Dynamic magnification: Kd100 / Ks)
The dynamic magnification was determined as a value of dynamic spring constant (Kd100) / static spring constant (Ks).

  From the results of Tables 1 to 4 above, when comparing the example product and the comparative example product with similar values of the static spring constant (Ks), only carbon black was used and 12-hydroxystearic acid was used in combination. Compared to the comparative example product, the example product using both carbon black and 12-hydroxystearic acid had a lower dynamic magnification and a better effect of reducing the dynamic magnification. That is, when the comparative example 5 product whose static spring constant (Ks) is 596 and the example 6 product whose static spring constant (Ks) is 612 are compared, only carbon black is used and 12-hydroxystearic acid is used. Compared with the comparative example 5 product which does not use together, the product of Example 6 which used carbon black and 12-hydroxystearic acid used together had a low dynamic magnification, and the low dynamic magnification reduction effect was favorable.

  Further, even when carbon black and 12-hydroxystearic acid are used in combination, the product of Example 5 in which the blending amount of 12-hydroxystearic acid is 20 parts (upper limit) is the blending amount of 12-hydroxystearic acid. Was 25 parts (exceeding the upper limit), and the effect of reducing the dynamic magnification was better than the comparative example 7 products.

  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.

Claims (3)

While containing the following (A)-(D) component, the compounding quantity of (B) component is set to the range of 0.5-20 weight part with respect to 100 weight part of (A) component, and (C The vibration-insulating rubber composition is characterized in that the blending amount of the component is set to 85 parts by weight or less with respect to 100 parts by weight of the component (A).
(A) Diene rubber.
(B) 12-hydroxystearic acid.
(C) Carbon black.
(D) Stearic acid.   The anti-vibration rubber composition according to claim 1, wherein the blending amount of the component (C) is set in a range of 20 to 70 parts by weight with respect to 100 parts by weight of the component (A).   An anti-vibration rubber using the anti-vibration rubber composition according to claim 1.