JP5364351B2 - Rubber composition for high damping rubber and high damping rubber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition exhibiting good processability for a highly damping rubber and, a highly damping rubber obtained by vulcanizing and molding the rubber composition for a highly damping rubber. <P>SOLUTION: The rubber composition for the highly damping rubber includes a butadiene rubber in an amount of 30-70 pts.wt. based on 100 pts.wt. of the total of rubber components, where the rubber composition for the highly damping rubber contains 30-45 pts.wt. of an alicyclic hydrocarbon resin, 10-20 pts.wt. of a rosin-based resin and 3-10 pts.wt. of a phenolic resin, each based on 100 pts.wt. of the total of the rubber components. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a rubber composition for high damping rubber having good processability, and a high damping rubber obtained by vulcanization and molding using the rubber composition for high damping rubber. Further, the present invention relates to a high-damping rubber that can be used for anti-vibration rubber for construction and general industrial use, and isolation rubber.

  Conventionally, natural rubber is often used as a rubber component of high-damping rubber, but rubber obtained by blending an appropriate vulcanizing agent with natural rubber, vulcanizing and molding is generally insufficient in damping characteristics. There are many. Therefore, usually by adding a large amount of asphalt, etc., the damping characteristics of such rubber are often improved. However, a rubber composition for a high-damping rubber in which a large amount of asphalt is added to natural rubber, such as rolls and banburys, etc. Over-adhesion to other processing machines is likely to occur. In addition, the rubber composition for high damping rubber has a high viscosity and high adhesiveness, resulting in roll stop due to torque over at the time of roll processing and rubber burn at the time of extrusion molding. There was a problem regarding the processability of the rubber composition for high damping rubber.

  In the following Patent Documents 1 and 2, as a seismic isolation rubber bearing body, the rubber layer is composed of butadiene rubber or 100 parts by weight of a rubber material mainly composed of butadiene rubber, and carbon black in a ratio of 50 to 150 parts by weight. Further improve the damping characteristics of the rubber layer by using a rubber composition for high-attenuation rubber that is compounded and further blended with 10 to 100 parts by weight of at least one of asphalts, tars, and pitches. It is described to do.

  However, although the above-described rubber has improved damping characteristics, it does not solve the above-described problem relating to the processability of the rubber composition for high-damping rubber. Also, if the asphalt, tars, or pitches are insufficiently dried or if they contain low molecular weight volatile components, the rubber layer after molding may foam (bubbles are generated). is there.

JP 2005-163855 A JP 2006-335052 A

  An object of the present invention is to provide a rubber composition for high damping rubber having good processability, and a high damping rubber obtained by vulcanization and molding using the rubber composition for high damping rubber. To do.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by the rubber composition for high damping rubber shown below, and have completed the present invention.

  That is, the rubber composition for high damping rubber according to the present invention is a rubber composition for high damping rubber containing butadiene rubber in an amount of 30 to 70 parts by weight with respect to 100 parts by weight of the rubber component. On the other hand, it is characterized by containing 30 to 45 parts by weight of an alicyclic hydrocarbon resin, 10 to 20 parts by weight of a rosin resin, and 3 to 10 parts by weight of a phenol resin.

  The rubber composition for high damping rubber contains a predetermined amount of butadiene rubber and resin, thereby suppressing the adhesiveness of the rubber composition and reducing the viscosity of the rubber composition. As a result, excessive adhesion of the rubber composition to a processing machine such as a roll or a banbury can be suppressed, and further, roll stop and rubber burn can be prevented, so that the processability of the rubber composition for high damping rubber is improved.

  Here, the content of the butadiene rubber with respect to 100 parts by weight of the total rubber component is 30 to 70 parts by weight, preferably 35 to 65 parts by weight, and more preferably 40 to 60 parts by weight. If the content of butadiene rubber in the total 100 parts by weight of the rubber component is less than 35 parts by weight, the damping characteristics of the vulcanized rubber tend to be reduced, and in addition, excessive adhesion to processing machines such as rolls and banbury is suppressed. Effect, and further, the effect of suppressing roll stoppage and rubber burning is reduced. On the other hand, when the content of butadiene rubber exceeds 70 parts by weight, the rubber strength of the vulcanized rubber tends to decrease.

  The content of the alicyclic hydrocarbon resin, rosin resin, and phenol resin is 30 to 45 parts by weight of the alicyclic hydrocarbon resin and rosin resin with respect to 100 parts by weight of the total rubber component. 10 to 20 parts by weight, and 3 to 10 parts by weight of the phenolic resin. If either the content of the alicyclic hydrocarbon-based resin or rosin-based resin is outside the above predetermined range, the rubber composition for high-attenuation rubber is excessively adhered to processing machines such as rolls and banburys. Furthermore, there is a tendency for roll stoppage and rubber burning to occur. Further, when the total content of the alicyclic hydrocarbon-based resin and the rosin-based resin is less than 40 parts by weight, when the rubber composition for a high-damping rubber is used as a vulcanized rubber (rubber layer), the damping property Tends to be insufficient. On the other hand, when the content of the alicyclic hydrocarbon resin exceeds 45 parts by weight, the rubber tends to foam when vulcanized rubber is used. Furthermore, when the content of the phenolic resin is less than 3 parts by weight, the adhesion to the metal plate tends to be insufficient when a vulcanized rubber (rubber layer) is used. In order to further improve the workability and adhesion while suppressing foaming of the rubber composition for high damping rubber, in order to further improve the damping property of the vulcanized rubber (rubber layer), an alicyclic hydrocarbon-based resin, The total content of the rosin resin and the phenol resin is preferably 50 to 60 parts by weight.

  In the rubber composition for high attenuation rubber, the cis rubber content of the butadiene rubber is preferably 95% or more. If the cis rubber content of the butadiene rubber is 95% or more in the rubber composition for high damping rubber, the rubber properties such as rubber strength of the vulcanized rubber are secured while ensuring good processability of the rubber composition for high damping. Will be improved.

  High damping rubbers obtained by vulcanization and molding using the rubber composition for high damping rubbers described above are anti-vibration rubbers for automobiles, vehicles, construction and general industries, and rubber for seismic isolation etc. It can be used for various applications that require attenuation characteristics.

  Commercially available butadiene rubber can be suitably used as the butadiene rubber in the present invention. Specifically, diene NF35R, diene 50RE, diene 531 (manufactured by Asahi Kasei), UBEPOL-BR150, 150B, 130B, 150L, 360L, 230, 700, 133P, UBEPOL-VCR412, 617, 450, 800 (Ube Industries, Ltd.) Product), JSR-BR01, T700, BR51, BR730 (manufactured by JSR), Nipol-BR1220, BR1220L, BR1242, BR1250H (manufactured by Nippon Zeon), and the like. Among these butadiene rubbers, butadiene rubber having a cis content of 95% or more is preferable.

  In the rubber composition for high damping rubber according to the present invention, examples of the rubber contained as a rubber component together with butadiene include natural rubber, chloroprene rubber, and diene synthetic rubber. Examples of the diene synthetic rubber include isoprene rubber, styrene butadiene rubber, butyl rubber, and acrylonitrile butadiene rubber. The polymerization method and microstructure of such a diene synthetic rubber are not limited, and one or more of these can be blended and used.

  In the present invention, an alicyclic hydrocarbon resin, a rosin resin, and a phenol resin are used as the resin.

  The alicyclic hydrocarbon-based resin is mainly produced using cyclopentadiene as a raw material, and examples of commercially available products include Quinton 1325 and Quinton 1345 (manufactured by Nippon Zeon Co., Ltd.).

  Examples of the rosin resin used in the present invention include rosin esters obtained by esterifying rosins and / or rosin derivatives and polyhydric alcohols. Examples of rosins include unmodified rosins such as tall oil rosin, gum rosin, and wood rosin mainly composed of a resin acid such as abietic acid, parastrinic acid, neoabietic acid, pimaric acid, isopimaric acid, or dehydroabietic acid. Examples of rosin derivatives include disproportionated rosin, polymerized rosin, hydrogenated rosin, other chemically modified rosin, and modified with unsaturated carboxylic acid modified with maleic acid, fumaric acid, (meth) acrylic acid, etc. Examples include rosins. On the other hand, examples of the polyhydric alcohol include dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and neopentyl glycol; trihydric alcohols such as glycerin, trimethylolethane, and trimethylolpropane; 4 such as pentaerythritol and diglycerin. Examples thereof include hexahydric alcohols such as dipentaerythritol, and one of these can be used alone or two or more can be used in combination. Commercially available products are also suitable as the rosin resin, and examples include Harrier Star P and Harrier Star C (manufactured by Harima Chemicals).

  As the phenolic resin, either a thermoplastic novolac type phenol resin or a resol type phenol resin can be used. For example, a novolac type phenol resin is obtained by mixing phenols such as phenol, p-cresol, m-cresol, p-tert-butylphenol or a mixture thereof with formaldehyde in the presence of an acid catalyst such as oxalic acid, hydrochloric acid, maleic acid, and the like. Obtained by a condensation reaction. A commercially available product is also suitable as the phenolic resin, and examples thereof include Sumilite resin 13349 (manufactured by Sumitomo Bakelite Co., Ltd.), which is a thermoplastic phenolic resin.

  The rubber composition for high damping rubber of the present invention comprises carbon rubber, silica, silane coupling agent, sulfur, zinc oxide, magnesium oxide, stearic acid, vulcanization accelerator, vulcanization acceleration aid together with the rubber component and resin. Additives usually used in the rubber industry such as vulcanization retarders, anti-aging agents, organic peroxides, softeners such as waxes and oils, processing aids, etc., as long as the effects of the present invention are not impaired. It can be blended and used.

  Examples of the carbon black include known carbon black having reinforcing properties, and specifically include, for example, SAF, ISAF, HAF, FEF, GPF and the like. The compounding amount of the carbon black is in the range of 50 to 150 parts by weight, preferably 80 to 120 parts by weight with respect to 100 parts by weight of the total rubber components. If the blending amount is less than 50 parts by weight, the reinforcing effect of the carbon black cannot be sufficiently obtained.

  Examples of sulfur include sulfur used in ordinary rubber industry. What is necessary is just to adjust the compounding quantity of sulfur suitably considering the rubber strength etc. of vulcanized rubber.

  As an anti-aging agent, an anti-aging agent used in a normal rubber industry can be used. For example, an amine-ketone type anti-aging agent, an aromatic amine type anti-aging agent, a phenol type anti-aging agent, a benzimidazole. Aging inhibitors, dithiocarbamate aging inhibitors, thiourea aging inhibitors and the like.

  As the vulcanization accelerator, a vulcanization accelerator used in a normal rubber industry can be used. For example, a thiourea vulcanization accelerator, a guanidine vulcanization accelerator, a thiazole vulcanization accelerator, Examples include phenamide vulcanization accelerators, thiuram vulcanization accelerators, and dithiocarbamic acid vulcanization accelerators.

  In the present invention, rubber components and resins, and, if necessary, carbon black, sulfur, zinc oxide, stearic acid, wax, oil, anti-aging agent, vulcanization accelerator, etc. are usually used as Banbury mixers, kneaders, rolls, etc. By kneading using a processing machine used in the rubber industry, it is possible to obtain a rubber composition for high damping rubber having good processability.

  In addition, the blending method of each of the above components is not particularly limited, and a blending component other than a vulcanizing component such as sulfur and a vulcanization accelerator is previously kneaded to obtain a master batch, and the remaining components are added and further kneaded. Any of a method of adding and kneading the components in an arbitrary order, a method of adding all of the components simultaneously and kneading may be used. High-attenuating rubber can be obtained by kneading and molding each of the above components, followed by vulcanization.

  Hereinafter, the present invention will be described in more detail with reference to examples.

(Preparation of rubber composition for high damping rubber)
According to the formulation of Table 1, the rubber compositions for high damping rubber of Examples 1 to 4 and Comparative Examples 1 to 5 were blended and kneaded using a normal roll to prepare a rubber composition for high damping rubber. Each compounding agent described in Table 1 is shown below.

a) Butadiene rubber ("UBEPOL-BR150; cis content 98%", manufactured by Ube Industries)
b) Natural rubber RSS # 3
c) Resin Alicyclic hydrocarbon resin (“Quinton 1325”, manufactured by Nippon Zeon Co., Ltd.)
Rosin resin ("Hari Star P", manufactured by Harima Chemicals)
Phenol resin ("Sumilite resin 13349", manufactured by Sumitomo Bakelite Co., Ltd.)
d) Zinc oxide No. 3 zinc white e) Stearic acid Industrial stearic acid f) Wax Microcrystalline wax g) Anti-aging agent (A) Aromatic amine-based anti-aging agent N-phenyl-N ′-(1,3-dimethyl) Butyl) -p-phenylenediamine ("NOCRACK 6C", manufactured by Ouchi Shinsei Chemical Co., Ltd.)
(B) Amine-ketone anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer ("Nonflex RD", manufactured by Seiko Chemical Co., Ltd.)
h) Carbon Black SAF ("Seast 9", manufactured by Tokai Carbon Co., Ltd.)
i) Aroma-based process oil ("Diana Process Oil AH-24", manufactured by Idemitsu Kosan Co., Ltd.)
j) Sulfur 5% oil-treated sulfur k) Vulcanization accelerator (A) Sulfenamide vulcanization accelerator N-cyclohexyl-2-benzothiazolylsulfenamide ("Noxeller CZ-G (CZ)", Ouchi Shinsei Chemical Industry)
(B) Thiuram-based vulcanization accelerator Tetramethylthiuram disulfide ("Noxeller TT-P (TT)", manufactured by Ouchi Shinsei Chemical Co., Ltd.)

(Evaluation)
Vulcanized rubbers obtained by heating and vulcanizing each rubber composition for high damping rubber at 160 ° C. for 30 minutes using a predetermined mold were evaluated.

<Processability>
When kneading each rubber composition using a normal roll, ○ when there is no work problem due to over-adhesion to the roll, when trouble occurs due to over-adhesion Was marked with x. The results are shown in Table 1.

<Foaming resistance (with or without air bubbles)>
The vulcanized rubber of each rubber composition for high damping rubber was arbitrarily cut and the presence or absence of bubbles in the cut surface was visually observed. The case where there were almost no bubbles was marked as ◯ (excellent in foam resistance), and there were many bubbles, for example, the case where tensile properties such as 300% elongation modulus and tensile strength deteriorated was marked as x (poor foam resistance). . The results are shown in Table 1.

<Adhesiveness>
Adhesiveness was evaluated in accordance with JIS K6256 by a 90-degree peeling test between a metal piece and rubber. Specific evaluation conditions are shown below.
(Test equipment)
As a general rule, the test equipment conforms to JIS B7721.
(Test pieces)
The test piece was made of rubber having a thickness of 6.0 ± 0.1 mm, a width of 25.0 ± 0.1 mm and a length of 125 mm, and a thickness of 1.5 mm ± 0.1 mm, a width of 25.0 ± 0.1 mm and a length. It is assumed that a metal piece having a thickness of 60 ± 1 mm is bonded so that an adhesive surface having a width of 25.0 ± 0.1 mm and a length of 25 mm is substantially at the center of the metal piece.
(Creation of specimen)
The test piece is prepared by the following method.
(1) Cellophane, release paper or the like is inserted between the metal surface and the unvulcanized rubber at a place other than the adhesive surface 25 × 25 mm of the test piece so that they do not adhere to each other.
(2) An unvulcanized rubber plate having a thickness of 8 mm is cut into a size corresponding to the vulcanization mold so that the unvulcanized rubber is sufficiently pressed against the metal surface.
(3) The inner dimension of the vulcanization mold is 125 mm in the vertical axis direction of the metal piece and 7.50 ± 0.05 mm in depth, and the horizontal axis direction is appropriately selected according to the number of test pieces.
(4) When removing the test piece after vulcanization from the vulcanization mold, care must be taken so that no force is applied to the adhesive surface before cooling.
(5) After leaving in the test room for 16 hours or more, cut each test piece with a knife or an appropriate blade, and remove the protruding rubber attached to the edges on both sides of the metal piece.
(Test method)
The test piece should be mounted so that the surface to be peeled off is horizontal and directed toward the tester, and the automatic recording device is operated until the peeling is completed. The maximum value during the test is obtained as the maximum peeling force. . Based on this maximum peel force, the peel strength (N / mm) is calculated by the following equation.
Ts = Fs / b
Here, Ts: peel strength (N / mm)
Fs: Maximum peeling force (N)
b: Width of metal piece (mm)
The case where the peel strength calculated based on the above formula was 9 N / mm or more was evaluated as ○, and the case where it was less than 9 N / mm was evaluated as ×.

<Damping (shear modulus, equivalent damping constant)>
A “2-block lap shear type” specimen (rubber part: width 25 mm, length 25 mm, thickness 5 mm) shown in FIG. 1 was prepared using each vulcanized rubber, and a frequency of 0 was obtained using a hydraulic vibration tester. A shear vibration is applied at 5 Hz under the following three series of strain conditions to obtain a stress-strain curve as shown in FIG. The measurement temperature was 20 ° C.
(Strain excitation condition)
1st series: Shake 10 times with 100% strain.
Second series: Excitation is performed 10 times with a strain of 200%.
3rd series: Excitation twice with 100% strain.
From the stress-strain curve shown in FIG. 2, the shear elastic modulus (Geq) and the equivalent damping constant (Heq) for the 10th excitation in the first series and the 2nd excitation in the third series are represented by the following formulas (1) and (1), respectively. Calculated from (2), the average value of both was taken as the shear modulus and equivalent damping constant of the rubber. Geq is set to an arbitrary value, and the higher the Heq, the better.
Geq (Kgf / cm ² ) = F / 2 (1)
Heq (%) = (ΔW / (W1 + W2)) × 1 / 2π × 100 (2)
Here, ΔW is the area in the loop of the stress-strain curve in FIG. 2, and W1 and W2 are the areas of the triangular regions in FIG. In addition, attenuation | damping evaluation was evaluated based on the value of Heq (%), and the case where the value was 20% or more was set to (circle), and the case where it was less than 20% was set to x. The results are shown in Table 1.

  From the results of Table 1, it can be seen that the rubber compositions for high damping rubber of Examples 1 to 4 are excellent in workability and adhesiveness while foaming is suppressed, and excellent in damping properties of the vulcanized rubber. On the other hand, since the rubber composition for high-damping rubber of Comparative Example 1 has a high content of the alicyclic hydrocarbon-based resin, foaming cannot be suppressed and processability is deteriorated. Moreover, since it does not contain a phenol resin, the adhesiveness is deteriorated. In addition, the rubber composition for high-damping rubber of Comparative Example 2 has deteriorated processability because it does not contain butadiene rubber. Furthermore, since it does not contain an alicyclic hydrocarbon-based resin, the damping property of the vulcanized rubber is deteriorated. Moreover, since the rubber composition for high damping rubber of Comparative Example 3 does not contain a phenolic resin, the adhesiveness is deteriorated. Moreover, since the rubber composition for high-damping rubber of Comparative Example 4 has a high content of rosin resin, processability is deteriorated. Furthermore, since the rubber composition for high-damping rubber of Comparative Example 5 has a high content of alicyclic hydrocarbon-based resin, foaming cannot be suppressed and processability is deteriorated.

The perspective view of a "2 block lap shear type" test body. Explanatory drawing of a stress-strain curve.

Claims (2)

In the rubber composition for high damping rubber containing butadiene rubber in an amount of 30 to 70 parts by weight with respect to 100 parts by weight of the total rubber components,
30 to 45 parts by weight of alicyclic hydrocarbon-based resin, 10 to 20 parts by weight of rosin-based resin, and 3 to 10 parts by weight of phenol-based resin with respect to 100 parts by weight of the total rubber component ,
A rubber composition for high damping rubber, wherein the cis rubber content of the butadiene rubber is 95% or more . Using the claim 1 Symbol placement of high damping rubber rubber composition for vulcanization, high damping rubber obtained by molding.

Images