JP2006037002A - Vibration-damping rubber composition and vibration-damping rubber member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a vibration-damping rubber composition small in a dynamic to static modulus ratio and high in durability, and a vibration-damping rubber member by using the vibration-damping rubber composition. <P>SOLUTION: The vibration-damping rubber composition is characterized by containing (A) a rubber component, (B) hydrophobically treated silica and (C) a silane-coupling agent. As the hydrophobically treated silica (B), it is preferable to blend 0.1-50 pts.wt. silicone oil having 10<SP>-6</SP>-1 m<SP>2</SP>/s range dynamic viscosity with 100 pts.wt. wet method silica having 30-230 m<SP>2</SP>/g range nitrogen-absorbing specific surface area (BET method) for surface-treating. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an anti-vibration rubber composition and an anti-vibration rubber member used for anti-vibration rubber for automobile vehicles and the like.

  The anti-vibration rubber composition used for the anti-vibration rubber for automobiles and the like has various blends, and usually contains rubber components such as natural rubber, as filler, carbon black, sulfur, zinc white, anti-aging agent, Vulcanization accelerators and the like are used. Among these, carbon black having a large particle size such as FEF or FT carbon is generally used. There are a number of reported examples of techniques for controlling the dynamic characteristics of anti-vibration rubber by the particle size, structure, and surface state of carbon black to reduce the dynamic ratio. In this case, when the blending amount is increased in order to increase the elastic modulus (static spring), the dynamic magnification increases, and there is a problem that when applied to an automobile, riding comfort is deteriorated and durability is also deteriorated.

On the other hand, an example using silica gel in which the disadvantages of carbon black are eliminated is known. As an anti-vibration rubber composition using silica gel as a filler, for example, an anti-vibration rubber composition for engine mount (see, for example, Patent Document 1) having a low BET specific surface area and low heat resistance and a silane cup. An anti-vibration rubber composition having a low dynamic magnification using natural silica subjected to a ring agent treatment (for example, see Patent Document 2) is known. Such an anti-vibration rubber composition is not sufficient, although the increase in dynamic magnification and the deterioration in durability are small compared to the case of using carbon black as a filler. Further, when silica is highly charged, there is a problem that Mooney viscosity increases and compression set properties deteriorate. From the above, further improvement is required in the vibration-proof rubber composition using silica.
JP-A-11-193338 JP 2002-98192 A

This invention is made | formed in view of the above conventional trouble, and makes it a subject to achieve the following objectives. That is,
An object of the present invention is to provide a vibration-proof rubber composition having a low dynamic magnification and high durability, and a vibration-proof rubber member using the vibration-proof rubber composition.

Means for solving the above-mentioned problems are as follows. That is,
<1> A vibration-proof rubber composition comprising a rubber component (A), a hydrophobized silica (B), and a silane coupling agent (C).

<2> The rubber component (A) is a natural rubber, butadiene rubber, isoprene, styrene butadiene rubber, EPDM, butyl rubber, halogenated butyl rubber, NBR, and CR. The anti-vibration rubber composition according to <1>, wherein the rubber composition is a rubber.

<3> The hydrophobized silica (B) has a kinematic viscosity of 10 ^{−6 to 1} m ² / s with respect to 100 parts by weight of wet silica having a nitrogen adsorption specific surface area (BET method) in the range of 30 to 230 m ² / g. The anti-vibration rubber composition according to <1> or <2>, wherein 0.1 to 50 parts by weight of the silicone oil in the range is blended and surface-treated.

<4> The vibration-insulating rubber composition according to any one of <1> to <3>, wherein the hydrophobized silica (B) has a DBA adsorption amount of 100 mmol / kg or less.

<5> From <1> to <1>, wherein the addition amount of the silane coupling agent (C) is 0.1 to 20% by mass with respect to the addition amount of the hydrophobized silica (B). 4> The vibration-proof rubber composition according to any one of 4).

<6> The anti-vibration rubber composition according to any one of <1> to <5>, wherein the silane coupling agent (C) has a molecular structure containing a sulfur atom or a nitrogen atom. is there.

<7> The above <1> to <6>, wherein the amount of the hydrophobized silica (B) is in the range of 10 to 150 parts by weight with respect to 100 parts by weight of the rubber component (A). The anti-vibration rubber composition according to any one of the above.

<8> An anti-vibration rubber member comprising the anti-vibration rubber composition according to any one of <1> to <7>.

  According to the present invention, it is possible to provide an anti-vibration rubber composition having a low dynamic magnification and high durability, and an anti-vibration rubber member using the anti-vibration rubber composition.

  The anti-vibration rubber composition of the present invention is characterized by containing a rubber component (A), a hydrophobized silica (B), and a silane coupling agent (C). Hereinafter, each component including the rubber component (A) will be described.

[Rubber component (A)]
Rubber components (A) include natural rubber, butadiene rubber (BR), styrene butadiene rubber (SBR), nitrile rubber (NBR), isoprene rubber (IR), diene rubbers such as chloroprene rubber (CR), ethylene propylene rubber, and the like. (EPR, EPDM), olefin rubber such as butyl rubber (IIR), halogenated butyl rubber such as brominated butyl rubber (Br-IIR), other polyurethane rubber, acrylic rubber, fluorine rubber, silicon rubber, chlorosulfonated polyethylene, etc. Synthetic rubbers, natural rubbers and the like are exemplified, and these can be used alone or in combination of two or more. Among these, natural rubber, butadiene rubber, isoprene, styrene butadiene rubber, EPDM, butyl rubber, halogenated butyl rubber, NBR, and rubber formed by blending one or more of these are suitable. More specifically, natural rubber alone, a combination of natural rubber and butadiene rubber, or a combination of natural rubber and styrene butadiene rubber is suitable.

[Hydrophobicized silica (B)]
In the present invention, hydrophobized silica is used as a filler, and by using the hydrophobized silica, the dynamic magnification which has been a problem of conventionally used carbon black and silica (untreated surface) is used. Can be greatly reduced and durability can be improved. Furthermore, it is possible to keep the increase in Mooney viscosity and the deterioration of the compression set property, which are problems in silica blending, small. Hydrophobized silica is considered to exhibit the above-mentioned effects because its surface state is more compatible with rubber components than ordinary silica.

The hydrophobized silica (B) has a kinematic viscosity in the range of 10 ^{−6 to 1} m ² / s with respect to 100 parts by weight of wet silica in the range of nitrogen adsorption specific surface area (BET method) of 30 to 230 m ² / g. It is preferable that 0.1 to 50 parts by weight of silicone oil is blended and surface-treated. When the nitrogen adsorption specific surface area (BET method) of wet silica is less than 30 m ² / g, the reinforcing property is low and the tensile strength is small. If it exceeds 230 m ² / g, dispersion into the rubber component becomes difficult. In addition, the kinematic viscosity of the silicone oil having a kinematic viscosity in the range of 10 ^{−6 to 1} m ² / s is a range that is normally used. Even if it exceeds 50 parts by weight, the effect of hydrophobization does not improve any more.

  The hydrophobized silica (B) preferably has a DBA (di-n-butylamine) adsorption amount of 100 mmol / kg or less. The DBA adsorption amount is a measure of the degree of hydrophobicity, and when the DBA adsorption amount exceeds 100 mmol / kg, the dynamic magnification, Mooney viscosity, and setability deteriorate. The DBA adsorption amount is preferably 80 mmol / kg or less. The lower limit is preferably 20 mmol / kg.

[Silane coupling agent (C)]
Examples of the silane coupling agent contained in the vibration-proof rubber composition of the present invention include vinyltriethoxysilane, vinyltrichlorosilane, γ-methacryloxypropyltrimethoxysilane, vinyltris (β-methoxy-ethoxy) silane, β -(3,4-epoxycyclohexyl) -ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxy Silane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ- Aminopropyltriethoxysilane And tetrasulfides such as γ-trimethoxysilylpropyldimethylthiocarbamyl tetrasulfide, γ-trimethoxysilylpropylbenzothiazyl tetrasulfide, and bis [3- (triethoxysilyl) propyl] tetrasulfide. Among these, a molecular structure containing a sulfur atom or a nitrogen atom is preferable.

  Examples of the silane coupling agent having a molecular structure containing a sulfur atom or a nitrogen atom include N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane and N- (β-aminoethyl) -γ-aminopropylmethyldimethoxy. Silane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, bis [3- (triethoxysilyl) propyl] tetrasulfide, γ-trimethoxysilylpropyl Examples include tetrasulfides such as benzothiazyl tetrasulfide and γ-trimethoxysilylpropylbenzothiazyl tetrasulfide, and γ-mercaptopropyltrimethoxysilane and bis [3- (triethoxysilyl) propyl] tetrasulfide are preferable. Used for Door can be.

  The addition amount of the silane coupling agent (C) is preferably 0.1 to 20% by mass, and 0.5 to 15% by mass with respect to the addition amount of the hydrophobized silica (B). More preferably, the content is 1 to 10% by mass. If it is less than 0.1% by mass, the coupling effect cannot be obtained, and the physical properties as rubber are remarkably lowered. Moreover, even if it adds exceeding 20 mass%, the effect beyond it will not be acquired.

  Various additives can be added to the vibration-proof rubber composition of the present invention as necessary. Examples of such additives include aging (oxidation) inhibitors, waxes, colorants, fillers, softeners such as plasticizers and process oils, and tackifiers.

  Examples of the filler include the following fillers. That is, metal powder such as aluminum powder, hard clay, talc, calcium carbonate, titanium oxide, calcium sulfate, calcium carbonate, aluminum hydroxide and other inorganic powders, powder such as organic powders such as starch and polystyrene powder; glass fiber ( Milled fibers), carbon fibers, aramid fibers, short fibers such as potassium titanate whiskers; carbon black, mica and the like. The above fillers are used alone or in combination of two or more. Further, these fillers may be added after performing surface treatment such as primer treatment and various coupling agent treatments as necessary.

  The softeners are classified into dicarboxylic acid esters such as dioctyl phthalate (DOP) and dioctyl sebacate, plasticizers exemplified by phosphoric acid esters, etc., and aromatic oils, naphthenic oils and paraffinic oils. Process oils. Among these softeners, plasticizers are mainly used as softeners for highly polar rubber materials such as NBR and polyurethane rubber, and process oils are mainly used for natural rubbers, but are not particularly limited. Two or more kinds may be used in combination.

  In the anti-vibration rubber composition of the present invention, as the crosslinking agent for crosslinking the rubber component, a normal crosslinking agent used for rubber crosslinking can be used without any particular limitation. For example, sulfur and a vulcanization accelerator can be used in sulfur crosslinking, and organic peroxides such as dicumyl peroxide, MEK peroxide, and benzoyl peroxide can be used in peroxide crosslinking. For IIR, oxime compounds such as phenol resin and benzoquinone oxime are used, and for CR, metal oxides such as zinc oxide and magnesium oxide, thiourea and the like are used. In addition to the above crosslinking method, crosslinking can also be performed by radiation such as an electron beam.

  The anti-vibration rubber composition of the present invention is kneaded and manufactured using a mixing apparatus such as a mixing roll, a Banbury mixer, a kneader and the like used in the technical field of rubber. At this time, heating is performed as necessary. As a molding method, various methods such as press molding, transfer molding, and injection molding can be appropriately employed depending on the shape to be molded. Moreover, when adhesion | attachment with a metal member is required, well-known rubber-metal adhesives, such as a metal lock series and a chemlock series, can be used suitably.

<Anti-vibration rubber member>
The anti-vibration rubber member of the present invention is characterized by using the anti-vibration rubber composition of the present invention. That is, the anti-vibration rubber member of the present invention is formed by vulcanization molding of the above-described anti-vibration rubber composition of the present invention.

  Specifically, the vibration isolator of the present invention includes an automobile engine mount, strut mount, member mount, suspension bush, toe collect bush, lower arm bush, differential mount, muffler hanger, spring seat, dynamic damper, viscous rubber damper, By applying it to a center support rubber or the like, a member having a low dynamic magnification and high durability can be obtained. That is, both dynamic magnification and durability can be improved at the same time.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example.

[Examples 1 to 3 and Comparative Examples 1 to 6]
For each Example and Comparative Example, the components shown in Table 1 were melt-kneaded to prepare anti-vibration rubber compositions of Examples 1 to 3 and Comparative Examples 1 to 6.

Details of the blending components abbreviated in Table 1 are shown below.
NIPSIL SS-30: Surface-treated silica (manufactured by Tosoh Silica Co., Ltd.)
NIPSIL VN3: Precipitated surface untreated silica (manufactured by Tosoh Silica Co., Ltd.)
SI-69: Silane coupling agent (Degussa)
RD: Anti-aging agent (Ouchi Shinsei Chemical Co., Ltd.)
6C: Anti-aging agent (made by Ouchi Shinsei Chemical Co., Ltd.)
CZ: Vulcanization accelerator (made by Ouchi Shinsei Chemical Co., Ltd.)

  In order to evaluate rubber physical properties, test pieces having predetermined dimensions were vulcanized and molded with respect to the obtained anti-vibration rubber compositions of Examples 1 to 3 and Comparative Examples 1 to 6, Mooney viscosity, rubber hardness Hs, and tensile strength. The rubber physical properties of elongation, Md50, and elongation fatigue durability were measured. The measurement method is shown below.

[Measuring method]
(1) Mooney viscosity The Mooney viscosity was measured according to the Mooney viscosity test of JIS K6300. The results are shown in Table 1.
(2) Rubber hardness Hs
The rubber hardness was measured according to JIS K 6301-1995 (25 ° C., spring type hardness (A type)). The results are shown in Table 1.
(3) Tensile strength (Tb), elongation, and Md50 (50% stress)
The tensile strength and elongation were measured according to JIS K6251. The results are shown in Table 1.
(4) Elongation fatigue endurance 200% elongation was repeated at room temperature, and the number N of times until breakage was counted. The results are shown in Table 1.

  A cylindrical test piece having a diameter of 30 mm and a height of 30 mm was prepared using each of the above vibration-proof rubber compositions. And using this test piece, the static spring constant (Ks), the dynamic spring constant (Kd @ 100Hz), and the dynamic magnification (Kd / Ks) were measured based on JISK6385. The results are shown in Table 1. The results are shown in Table 1. Each measuring method and evaluation method are as follows.

・ Static spring constant Ks
In accordance with JIS K 6385, in the bi-directional load method of static characteristic test, a deflection in the range of 0 mm to +4.5 mm is applied three times in the direction perpendicular to the axis of the test piece at a displacement speed of 20 mm / min. The load-deflection relationship in the process was measured, and using this relationship, the deflection range was calculated in the range of 1.5 to 3.0 mm by the calculation method described in the same standard.

・ Dynamic spring constant Kd
Also called storage spring constant, in accordance with JIS K 6385, in a non-resonant method of the dynamic property measurement test, under a load of 10% (3 mm), a vibration frequency of 100 Hz and an amplitude ±± It measured on condition at 0.05 mm.

  Moreover, the cylindrical engine mount for motor vehicles was produced using each said vibration-proof rubber composition. For the engine mounts of Examples 1 to 3 and Comparative Examples 1 to 6 obtained, the ride comfort is determined by mounting the engine mount on a passenger car, measuring the vibration in the passenger compartment and the booming noise transmitted from the engine vibration, Evaluation was made with “◯” indicating that there was little muffled sound, and “×” indicating that there was no noise. The results are shown in Table 1.

  From Table 1, Examples 1-3 were small in dynamic magnification and high in durability, while Comparative Examples 1-6 were all or any of dynamic magnification, durability, and workability (evaluated from Mooney viscosity). It was inferior.

Claims (8)

  An anti-vibration rubber composition comprising a rubber component (A), a hydrophobized silica (B), and a silane coupling agent (C).   The rubber component (A) is a rubber obtained by blending any one of natural rubber, butadiene rubber, isoprene, styrene butadiene rubber, EPDM, butyl rubber, halogenated butyl rubber, NBR, and CR. The anti-vibration rubber composition according to claim 1, wherein the anti-vibration rubber composition is provided. The hydrophobized silica (B) has a kinematic viscosity in the range of 10 ^{−6 to 1} m ² / s with respect to 100 parts by weight of wet silica having a nitrogen adsorption specific surface area (BET method) in the range of 30 to 230 m ² / g. The anti-vibration rubber composition according to claim 1 or 2, wherein 0.1 to 50 parts by weight of silicone oil is blended and surface-treated.   The vibration-insulating rubber composition according to any one of claims 1 to 3, wherein the hydrophobized silica (B) has a DBA adsorption amount of 100 mmol / kg or less.   The addition amount of the silane coupling agent (C) is 0.1 to 20% by mass with respect to the addition amount of the hydrophobized silica (B). Anti-vibration rubber composition according to item.   The vibration-insulating rubber composition according to any one of claims 1 to 5, wherein the silane coupling agent (C) has a molecular structure containing a sulfur atom or a nitrogen atom.   The amount of the hydrophobized silica (B) added is in the range of 10 to 150 parts by weight with respect to 100 parts by weight of the rubber component (A). Anti-vibration rubber composition.   An anti-vibration rubber member comprising the anti-vibration rubber composition according to any one of claims 1 to 7.