JP6644962B1 - Anti-vibration rubber composition and anti-vibration rubber member - Google Patents

Abstract

An anti-vibration rubber composition comprising the following components (C) and (D) together with a polymer comprising the following components (A) and (B), wherein the proportion of the components (A) and (B) is In the ratio, it is assumed that (A) / (B) = 9/1 to 2/8. This improves the processability of the rubber composition, such as roll kneading, while satisfying the characteristics required for a vibration-proof rubber such as a low dynamic magnification. (A) Natural rubber. (B) Polyisoprene rubber. (C) filler. (D) A dihydrazide compound represented by the following general formula (1).

Description

  The present invention relates to an anti-vibration rubber composition and an anti-vibration rubber member used for anti-vibration applications in vehicles such as automobiles and trains.

In the technical field of anti-vibration rubber, values of high durability, suppression of increase in loss coefficient tan δ (loss factor), and reduction in dynamic magnification (dynamic magnification [dynamic spring constant (Kd) / static spring constant (Ks)]) Must be reduced).
In such a situation, a method of lowering the dynamic magnification and suppressing an increase in the loss factor by adding a hydrazide compound to the rubber composition has been sought (for example, see Patent Documents 1 and 2).

JP 2010-121082 A JP 2001-172435 A

However, hydrazide compounds have high reactivity, and particularly dihydrazide compounds have higher reactivity.If only the above-mentioned method is used to reduce the dynamic magnification and suppress the increase of the loss factor, etc., the reactivity of the dihydrazide compound becomes high. Due to the above, a large problem occurs during roll kneading of the rubber composition.
More specifically, the vibration-isolating rubber composition is usually prepared by first kneading a rubber material excluding a vulcanizing agent and a vulcanization accelerator with a Banbury mixer or the like, and then transferring the rubber material to a roll kneading machine such as an open roll to obtain a vulcanizing agent. And a vulcanization accelerator are added. Then, as described above, when an attempt is made to reduce the dynamic magnification and suppress the increase in the loss factor by using only the dihydrazide compound, the reaction of the rubber composition proceeds too much during kneading by the roll kneader, and the elongation is lost. As a result, as shown in FIG. 2, a large number of holes and tears are generated in the rubber composition, which has an effect on workability such as not being wound around a roll, and the kneading operation by the roll kneading machine cannot be continued as it is. Causes malfunction.

  The present invention has been made in view of the above circumstances, and has an improved vibration-proofing property such as roll kneading of a rubber composition while satisfying characteristics required for a vibration-proof rubber such as a low dynamic magnification. Provided are a rubber composition and a vibration-proof rubber member.

  The present inventors have intensively studied to solve the above-mentioned problems. In the course of the research, natural rubber generally used as a polymer of the vibration-isolating rubber composition contains impurities such as proteins, and the reactivity of the hydrazide compound with respect to these impurities is extremely high. The present inventors have found that the high workability causes the deterioration in workability during the roll kneading as described above. Therefore, the use of polyisoprene rubber, which is a synthetic rubber having a molecular structure very close to that of natural rubber and containing no impurities such as proteins as described above, was examined in place of natural rubber. However, when only the polyisoprene rubber is used as the polymer, the unvulcanized viscosity of the rubber composition becomes high, so that it becomes difficult to mold the rubber composition after the roll kneading by injection molding or the like. . Therefore, when natural rubber and polyisoprene rubber were used together in a specific ratio, even when a dihydrazide compound having higher reactivity was used, perforations and tears as shown in FIG. It hardly occurs (see FIG. 1), and the use of a specific dihydrazide compound represented by the following general formula (1) gives satisfactory results such as a low dynamic magnification, so that the intended purpose can be achieved. I found it.

［２］上記ジヒドラジド化合物（Ｄ）の含有割合が、上記防振ゴム組成物中のポリマーの全量１００重量部に対して０．０１〜５．０重量部の範囲である、［１］に記載の防振ゴム組成物。
［３］上記ジヒドラジド化合物（Ｄ）が、アジピン酸ジヒドラジドおよびイソフタル酸ジヒドラジドから選ばれた少なくとも一方である、［１］または［２］に記載の防振ゴム組成物。
［４］上記ポリイソプレンゴム（Ｂ）の１００℃におけるムーニー粘度が、６５以上である、［１］〜［３］のいずれかに記載の防振ゴム組成物。
［５］上記充填剤（Ｃ）の含有割合が、上記防振ゴム組成物中のポリマーの全量１００重量部に対して５〜１００重量部の範囲である、［１］〜［４］のいずれかに記載の防振ゴム組成物。
［６］上記充填剤（Ｃ）がカーボンブラックである、［１］〜［５］のいずれかに記載の防振ゴム組成物。
［７］上記充填剤（Ｃ）の９０重量％以上がカーボンブラックである、［１］〜［５］のいずれかに記載の防振ゴム組成物。
［８］上記充填剤（Ｃ）が、カーボンブラックおよびシリカからなり、カーボンブラックとシリカとを、重量比で、カーボンブラック／シリカ＝８０／２０〜２０／８０の割合で含有する、［１］〜［５］のいずれかに記載の防振ゴム組成物。
［９］上記充填剤（Ｃ）に含まれるカーボンブラックが、ＦＥＦ級カーボンブラックである、［６］〜［８］のいずれかに記載の防振ゴム組成物。
［１０］［１］〜［９］のいずれかに記載の防振ゴム組成物の加硫体からなることを特徴とする防振ゴム部材。That is, the present invention has the following [1] to [10] as its gist in order to achieve the above object.
[1] An anti-vibration rubber composition containing the following components (C) and (D) together with a polymer composed of the following components (A) and (B), and the proportion of the components (A) and (B): Is a weight ratio of (A) / (B) = 9/1 to 2/8.
(A) Natural rubber.
(B) Polyisoprene rubber.
(C) filler.
(D) A dihydrazide compound represented by the following general formula (1).

[2] The content according to [1], wherein the content of the dihydrazide compound (D) is in the range of 0.01 to 5.0 parts by weight based on 100 parts by weight of the total amount of the polymer in the vibration-proof rubber composition. Anti-vibration rubber composition.
[3] The anti-vibration rubber composition according to [1] or [2], wherein the dihydrazide compound (D) is at least one selected from adipic dihydrazide and isophthalic dihydrazide.
[4] The anti-vibration rubber composition according to any one of [1] to [3], wherein the polyisoprene rubber (B) has a Mooney viscosity at 100 ° C of 65 or more.
[5] Any one of [1] to [4], wherein the content of the filler (C) is in the range of 5 to 100 parts by weight based on 100 parts by weight of the total amount of the polymer in the vibration-proof rubber composition. A vibration-isolating rubber composition as described in Crab.
[6] The anti-vibration rubber composition according to any one of [1] to [5], wherein the filler (C) is carbon black.
[7] The rubber cushion composition according to any one of [1] to [5], wherein 90% by weight or more of the filler (C) is carbon black.
[8] The filler (C) is composed of carbon black and silica, and contains carbon black and silica in a weight ratio of carbon black / silica = 80/20 to 20/80, [1]. -The vibration-proof rubber composition according to any one of [5].
[9] The anti-vibration rubber composition according to any one of [6] to [8], wherein the carbon black contained in the filler (C) is an FEF-grade carbon black.
[10] An anti-vibration rubber member comprising a vulcanized product of the anti-vibration rubber composition according to any one of [1] to [9].

  From the above, the anti-vibration rubber composition of the present invention can exhibit characteristics excellent in processability such as roll kneading while satisfying characteristics required for the anti-vibration rubber, such as low dynamic magnification. .

It is explanatory drawing which shows the state after roll kneading of the vibration-proof rubber composition of this invention. It is explanatory drawing which shows the state after roll kneading of the conventional vibration-proof rubber composition.

  Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to this embodiment.

As described above, the anti-vibration rubber composition of the present invention comprises a polymer comprising the following components (A) and (B), and the following components (C) and (D): Wherein the ratio of the components (A) and (B) is in the range of (A) / (B) = 9/1 to 2/8 by weight.
(A) Natural rubber.
(B) Polyisoprene rubber.
(C) filler.
(D) A dihydrazide compound represented by the following general formula (1).

In the vibration damping rubber composition of the present invention, the mixing ratio (weight ratio) of the natural rubber (A) and the polyisoprene rubber (B) is adjusted as described above (A) from the viewpoint of improving processability such as roll kneading. It is particularly important to set the range of () / (B) = 9/1 to 2/8. And from a similar viewpoint, the weight ratio [(A) / (B)] is preferably in the range of 8/2 to 3/7, and more preferably in the range of 8/2 to 4/6. . More preferably, it is in the range of 8/2 to 6/4. That is, when the ratio of the natural rubber (A) is too large (the ratio of the polyisoprene rubber (B) is too small), the reactivity with the dihydrazide compound (D) becomes too high, and the roll kneading is shown in FIG. Such perforations and tears occur, and conversely, if the proportion of the natural rubber (A) is too small (the proportion of the polyisoprene rubber (B) is too large), the unvulcanized viscosity of the rubber composition is reduced. This is because it is difficult to mold the rubber composition after the above-mentioned roll kneading by injection molding or the like, or the storage stability is deteriorated.
Here, the polymer comprising the components (A) and (B) preferably accounts for 80% by weight or more of the polymer in the vibration-proof rubber composition, and more preferably, the polymer in the vibration-proof rubber composition. Occupies at least 90% by weight of the polymer, more preferably all of the polymer in the vibration-proof rubber composition. Within such a range, low dynamic magnification and roll workability will be good.
When a polymer other than the components (A) and (B) is included in the above range, for example, butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR) Are used in combination.

  As the polyisoprene rubber (B), those having a Mooney viscosity at 100 ° C. of 65 or more are preferably used from the viewpoint of mixing properties and roll processability. More preferably, the polyisoprene rubber having the Mooney viscosity of 70 to 110 is used. The Mooney viscosity can be measured according to JIS K 6300-1.

  As the filler (C), carbon black, silica, calcium carbonate and the like are used alone or in combination of two or more. Among them, carbon black is preferable from the viewpoint of vibration characteristics, and it is desirable that 90% by weight or more of the filler (C) is carbon black.

  As the carbon black, for example, 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 are used. These may be used alone or in combination of two or more. Among them, FEF grade carbon black is preferably used from the viewpoint of vibration characteristics and fatigue resistance.

  As the silica, for example, wet silica, dry silica, colloidal silica and the like are used. These may be used alone or in combination of two or more.

From the viewpoint of achieving higher durability, suppressing a loss factor increase, and achieving a lower dynamic magnification, the BET specific surface area of the silica is preferably 50 to 320 m ² / g, more preferably a BET ratio. Silica having a surface area of 70 to 230 m ² / g, and more preferably a BET specific surface area of 70 to 120 m ² / g.
The BET specific surface area of the above silica is determined, for example, by degassing a sample at 200 ° C. for 15 minutes and then using a mixed gas (N ₂ : 70%, He: 30%) as an adsorbed gas. (Manufactured by Micro Data, 4232-II).

  In the case where only carbon black and silica are used in combination as the filler (C), the ratio of carbon black / silica in the ratio of 80/20 to 20/80 in terms of weight ratio is not limited. It is preferable from the viewpoint of fatigue. From the same viewpoint, in the above case, it is more preferable that carbon black / silica is contained at a ratio of 40/60 to 20/80, and it is further preferable that carbon black / silica is 30/70 to 20/80. 80 at a rate.

  The total content of the filler (C) is in the range of 5 to 100 parts by weight based on 100 parts by weight of the polymer in the vibration-proof rubber composition of the present invention from the viewpoint of fatigue resistance. Is more preferable, more preferably in the range of 20 to 80 parts by weight, and still more preferably in the range of 40 to 70 parts by weight.

  As the dihydrazide compound (D), as described above, a dihydrazide compound represented by the following general formula (1) is used because the increase in dynamic magnification can be effectively suppressed.

  In the above general formula (1), R is preferably an alkylene group having 4 to 12 carbon atoms or a cycloalkylene group having 3 to 10 carbon atoms.

  Specific examples of the dihydrazide compound (D) include, for example, adipic dihydrazide, isophthalic dihydrazide, phthalic dihydrazide, terephthalic dihydrazide, succinic dihydrazide, azelaic dihydrazide, sebacic dihydrazide, oxalic dihydrazide, Dihydrazide and the like. These may be used alone or in combination of two or more. Of these, adipic acid dihydrazide and isophthalic acid dihydrazide are preferred from the viewpoint of lowering the dynamic magnification.

  The content of the dihydrazide compound (D) is 0.01 to 5.0 parts by weight with respect to 100 parts by weight of the total amount of the polymer in the vibration-proof rubber composition of the present invention from the viewpoint of lowering the dynamic magnification. It is preferably in the range of 0.1 to 3 parts by weight, more preferably 1 to 3 parts by weight.

  In addition, in the vibration damping rubber composition of the present invention, a silane coupling agent, a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, an antiaging agent, together with the essential components (A) to (D). Agents, process oils and the like can be appropriately contained as necessary.

  Examples of the silane coupling agent include, for example, a mercapto silane coupling agent, a sulfide silane coupling agent, an amine silane coupling agent, an epoxy silane coupling agent, a vinyl silane coupling agent, and the like, alone or Used in combination of two or more. In particular, it is preferable that the silane coupling agent is a mercapto-based silane coupling agent or a sulfide-based silane coupling agent, because the vulcanization density is increased, and a low dynamic magnification and durability are particularly effective.

  Examples of the mercapto-based silane coupling agent include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and the like. These may be used alone or in combination of two or more.

  Examples of the sulfide-based silane coupling agent include bis- (3- (triethoxysilyl) -propyl) -disulfide, bis (3-triethoxysilylpropyl) trisulfide, and bis- (3- (triethoxysilyl)). -Propyl) -tetrasulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) ) Disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthio Cal Moyltetrasulfide, 2-trimethoxysilylethyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-trimethoxysilylpropylbenzothiazolyltetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilyl Propyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide and the like. These may be used alone or in combination of two or more.

  Examples of the amine silane coupling agent include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, and N- (2- (Aminoethyl) -3-aminopropylmethyldimethoxysilane, 3- (N-phenyl) aminopropyltrimethoxysilane and the like. These may be used alone or in combination of two or more.

  Examples of the epoxy silane coupling agent include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, Glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane and the like can be mentioned. These may be used alone or in combination of two or more.

  Examples of the vinyl silane coupling agent include vinyl triethoxy silane, vinyl trimethoxy silane, vinyl tris (β-methoxy ethoxy) silane, vinyl dimethyl chloro silane, vinyl trichloro silane, vinyl triisopropoxy silane, and vinyl tris (2-methoxyethoxy) silane and the like. These may be used alone or in combination of two or more.

  The content of these silane coupling agents is 0.5 to 20 parts by weight based on 100 parts by weight of the total amount of the polymer in the vibration-proof rubber composition of the present invention because the low dynamic magnification and the durability are excellent. Preferably, it is 1.0 to 10 parts by weight.

  Examples of the vulcanizing agent include sulfur (powder sulfur, precipitated sulfur, insoluble sulfur) and sulfur-containing compounds such as alkylphenol disulfide. These may be used alone or in combination of two or more.

  Further, the content of the vulcanizing agent is preferably in the range of 0.1 to 10 parts by weight, particularly preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the total amount of the polymer in the vibration-proof rubber composition of the present invention. It is in the range of parts by weight. That is, when the content of the vulcanizing agent is too small, the vulcanization reactivity tends to be deteriorated. On the contrary, when the content of the vulcanizing agent is too large, the rubber properties (rupture strength, elongation at break) are reduced. This is because there is a tendency to decrease.

  Examples of the vulcanization accelerator include thiuram-based, sulfenamide-based, guanidine-based, thiazole-based, aldehyde-ammonia-based, aldehydeamine-based, and thiourea-based vulcanization accelerators. These may be used alone or in combination of two or more. Among these, a combination of a thiuram-based vulcanization accelerator and at least one vulcanization accelerator selected from a sulfenamide-based, guanidine-based, and thiazole-based one, because of its excellent compression set. Is preferred.

  Further, the content of the vulcanization accelerator is preferably in the range of 0.1 to 10 parts by weight, particularly preferably 0.3 to 10 parts by weight, based on 100 parts by weight of the total amount of the polymer in the vibration-proof rubber composition of the present invention. The range is 5 parts by weight.

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

  Examples of the sulfenamide vulcanization accelerator include N-oxydiethylene-2-benzothiazolylsulfenamide (NOBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), and Nt -Butyl-2-benzothiazolesulfenamide (BBS), N, N'-dicyclohexyl-2-benzothiazolesulfenamide and the like. These may be used alone or in combination of two or more.

  Examples of the guanidine vulcanization accelerator include N, N'-diphenylthiourea, trimethylthiourea, N, N'-diethylthiourea, and N, N'-dibutylthiourea. These may be used alone or in combination of two or more.

  Examples of the thiazole vulcanization accelerator include dibenzothiazyl disulfide (MBTS), 2-mercaptobenzothiazole (MBT), 2-mercaptobenzothiazole sodium salt (NaMBT), and 2-mercaptobenzothiazole zinc salt (ZnMBT). And the like. 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 vulcanization reactivity.

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

  Further, the content of the vulcanization aid is preferably in the range of 0.1 to 10 parts by weight, more preferably 0.3 to 10 parts by weight, based on 100 parts by weight of the total amount of the polymer in the vibration-proof rubber composition of the present invention. It is in the range of 7 parts by weight.

  Examples of the antioxidant include, for example, carbamate antioxidants, phenylenediamine antioxidants, phenolic antioxidants, diphenylamine antioxidants, quinoline antioxidants, imidazole antioxidants, waxes and the like. can give. These may be used alone or in combination of two or more.

  The content of the antioxidant is preferably in the range of 0.5 to 15 parts by weight, particularly preferably 1 to 10 parts by weight, based on 100 parts by weight of the total amount of the polymer in the vibration-proof rubber composition of the present invention. Range.

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

  Further, the content of the process oil is preferably in the range of 1 to 35 parts by weight, particularly preferably in the range of 3 to 30 parts by weight, based on 100 parts by weight of the total amount of the polymer in the vibration-proof rubber composition of the present invention. is there.

(Preparation method of anti-vibration rubber composition)
Here, the anti-vibration rubber composition of the present invention uses the essential components (A) to (D) and, if necessary, other materials listed above, and kneads them using a kneader, a Banbury mixer, an open It can be prepared by kneading using a kneader such as a roll or a twin screw stirrer. In addition, it is preferable that each of the above materials is kneaded with all the materials at the same time, but when a vulcanizing agent and a vulcanization accelerator are blended, all the materials except the vulcanizing agent and the vulcanization accelerator are kneaded at the same time. Thereafter, it is preferable to add a vulcanizing agent and a vulcanization accelerator.

  The anti-vibration rubber composition of the present invention thus obtained is molded by injection molding or the like at a high temperature (150 to 170 ° C.) for 5 to 30 minutes to obtain a desired anti-vibration rubber member (vulcanized). Body) can be manufactured.

And the vibration-proof rubber member made of the vulcanized body of the vibration-proof rubber composition of the present invention is preferably used as a constituent member of an engine mount, a stabilizer bush, a suspension bush, a motor mount, a sub-frame mount and the like used for an automobile vehicle or the like. Used. Among them, an electric vehicle powered by an electric motor (an electric vehicle (EV), a fuel cell vehicle (FCV), a plug-in hybrid vehicle (PHV), It can be advantageously used for components such as motor mounts, suspension bushes, and subframe mounts (including vibration-proof rubber members for electric vehicles) for use in hybrid vehicles (HV).
In addition to the above applications, vibration dampers for computer hard disks, vibration dampers for general home appliances such as washing machines, vibration damping walls for buildings in the building and housing fields, and vibration damping (vibration damping) dampers. It can also be used for (vibration suppression) devices and seismic isolation devices.

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

First, prior to Examples and Comparative Examples, the following materials were prepared.
The Mooney viscosity of the polyisoprene rubber shown below is a value measured according to JIS K 6300-1, and the BET specific surface area of the silica shown below is a value measured according to the above method. is there.

[Natural rubber (NR)]

[Polyisoprene rubber (IR)]
NIPOL IR2200 manufactured by ZEON CORPORATION (Mooney viscosity at 100 ° C .: 82)

(Zinc oxide)
Two types of zinc oxide manufactured by Sakai Chemical Industry Co., Ltd.

〔stearic acid〕
NOF Corporation, beads stearic acid sakura

(Anti-aging agent)
Sumitomo Chemical Co., Antigen 6C

(Carbon black (i))
Seat SO (FEF grade carbon black) manufactured by Tokai Carbon Co., Ltd.

(Carbon black (ii))
Seat TA (FT grade carbon black) manufactured by Tokai Carbon Co., Ltd.

(Silica (i))
Nip Seal VN3 (BET specific surface area: 180-230 m ² / g) manufactured by Tosoh Silica Corporation

(Silica (ii))
NIPSEAL ER (BET specific surface area 70-120 m ² / g) manufactured by Tosoh Silica Corporation

[Process oil]
Nippon Sun Oil Co., Ltd., Sansen 410

(Dihydrazide (i))
Otsuka Chemical Co., Ltd., isophthalic dihydrazide (IDH)

(Dihydrazide (ii))
Otsuka Chemical Co., Ltd., adipic dihydrazide (ADH)

(Monohydrazide)
Otsuka Chemical Co., Ltd., naphthoic hydrazide (HNH)

〔Silane coupling agent〕
NXT Z45 manufactured by MOMENTIVE

(Vulcanization accelerator)
Suncellar CZ-G, manufactured by Sanshin Chemical Industry Co., Ltd.

[Sulfur (vulcanizing agent)]
Karuizawa smelter

[Examples 1 to 13, Comparative Examples 1 to 8]
The above materials were blended and kneaded at the ratios shown in Tables 1 and 2 below to prepare a vibration-proof rubber composition. The kneading is carried out by first kneading materials other than the vulcanizing agent and the vulcanization accelerator at 140 ° C. for 5 minutes using a Banbury mixer, then compounding the vulcanizing agent and the vulcanization accelerator, And kneading at 60 ° C. for 5 minutes.

  Using the vibration-proof rubber compositions of Examples and Comparative Examples thus obtained, each property was evaluated according to the following criteria. The results are shown in Tables 1 and 2 below.

≪Roll workability≫
The anti-vibration rubber composition after kneading with the above open roll was visually observed, and a large number of holes or tears that could not be wound around the roll (see FIG. 2) were evaluated as "x", and wound around the roll. Although not so bad, a case where many holes and tears occurred was evaluated as “△”, and a case where almost no holes and tears occurred (see FIG. 1) was evaluated as “〇”.

≪Unvulcanized viscosity≫
The Mooney viscosity (unvulcanized viscosity) at 125 ° C. was measured for the vibration-proof rubber composition after kneading with the open roll according to JIS K 6300-1.
In Tables 1 and 2 below, the measured values of the unvulcanized viscosities in each of Examples and Comparative Examples, when the measured values of the unvulcanized viscosities in Comparative Example 1 were 100, were converted to exponential values. Notation.
Those having a value of less than 160 were evaluated as “「 ”, and those having a value of 160 or more were evaluated as“ x ”.
In addition, it shows that the smaller the value of the unvulcanized viscosity is, the more excellent the injection moldability of the unvulcanized rubber is.

≪Dynamic magnification≫
The anti-vibration rubber composition after kneading with the open roll was press-molded (vulcanized) to produce a test piece. The static spring constant (Ks) of the test piece was measured according to JIS K 6394, and the dynamic spring constant (Kd100) at a frequency of 100 Hz of the test piece was determined according to JIS K 6385. The dynamic magnification (Kd100 / Ks) was calculated based on those values.
In Tables 1 and 2 below, when the measured value of the dynamic magnification (Kd100 / Ks) in Comparative Example 1 was set to 100, the measured value of the dynamic magnification in each example was expressed as an index. Those having a value of less than 95 were evaluated as “「 ”, and those having a value of 95 or more were evaluated as“ x ”.
The smaller the value of the dynamic magnification is, the more excellent the anti-vibration characteristics are.

From the results shown in Tables 1 and 2, the vibration-proof rubber compositions of Examples are excellent in roll processability, achieve low dynamic magnification, and have low unvulcanized viscosity. It can be seen that is also excellent.
On the other hand, the anti-vibration rubber composition of Comparative Example 1 containing no dihydrazide compound and the anti-vibration rubber composition of Comparative Example 4 containing monohydrazide instead of the dihydrazide compound did not show any deterioration in roll processability. As a result, it was not possible to achieve the desired low dynamic magnification. The anti-vibration rubber compositions of Comparative Examples 2 and 3 used only natural rubber as the polymer, and resulted in a noticeable deterioration in roll processability due to the dihydrazide compound. Although the natural rubber and the polyisoprene rubber were used in combination in the vibration-proof rubber composition of Comparative Example 5, sufficient improvement in roll processability was not recognized because the proportion of the polyisoprene rubber was too small. The anti-vibration rubber composition of Comparative Example 6 used only polyisoprene rubber as the polymer, and had a high unvulcanized viscosity, which resulted in concern about the effect on injection moldability. The anti-vibration rubber compositions of Comparative Examples 7 and 8 attempt to improve physical properties by changing the filler and using a silane coupling agent with respect to the anti-vibration rubber compositions of Comparative Example 3. No improvement in roll workability was made.

  In addition, in the said Example, although the specific form in this invention was shown, the said Example is only a mere illustration and is not interpreted restrictively. Various modifications apparent to those skilled in the art are contemplated to be within the scope of the present invention.

  The anti-vibration rubber composition of the present invention is preferably used as a material for components (anti-vibration rubber members) such as an engine mount, a stabilizer bush, a suspension bush, a motor mount, and a sub-frame mount used in automobiles and the like. In addition, vibration dampers for computer hard disks, vibration dampers for general home appliances such as washing machines, vibration damping walls for buildings in the construction and housing fields, and vibration damping dampers (vibration damping) dampers etc. ) It can also be used as a material for components of the device and the seismic isolation device (anti-vibration rubber member).

Claims (10)

An anti-vibration rubber composition containing the following components (C) and (D) together with a polymer comprising the following components (A) and (B), wherein the proportion of the components (A) and (B) is (A) / (B) = 9/1 to 2/8 in a ratio.
(A) Natural rubber.
(B) Polyisoprene rubber.
(C) filler.
(D) A dihydrazide compound represented by the following general formula (1).

  The vibration-proof rubber according to claim 1, wherein the content ratio of the dihydrazide compound (D) is in the range of 0.01 to 5.0 parts by weight based on 100 parts by weight of the total amount of the polymer in the vibration-proof rubber composition. Composition.   The vibration-proof rubber composition according to claim 1 or 2, wherein the dihydrazide compound (D) is at least one selected from adipic dihydrazide and isophthalic dihydrazide.   The anti-vibration rubber composition according to any one of claims 1 to 3, wherein the polyisoprene rubber (B) has a Mooney viscosity at 100 ° C of 65 or more.   The content ratio of the filler (C) is in the range of 5 to 100 parts by weight based on 100 parts by weight of the total amount of the polymer in the vibration-proof rubber composition. Anti-vibration rubber composition.   The anti-vibration rubber composition according to any one of claims 1 to 5, wherein the filler (C) is carbon black.   The rubber composition according to any one of claims 1 to 5, wherein 90% by weight or more of the filler (C) is carbon black.   6. The filler according to claim 1, wherein the filler (C) comprises carbon black and silica, and contains carbon black and silica at a weight ratio of carbon black / silica = 80/20 to 20/80. The anti-vibration rubber composition according to any one of the above.   The anti-vibration rubber composition according to any one of claims 6 to 8, wherein the carbon black contained in the filler (C) is FEF grade carbon black.   An anti-vibration rubber member comprising a vulcanized product of the anti-vibration rubber composition according to claim 1.

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