JP6754226B2 - Rubber composition, rubber composition for anti-vibration rubber products and anti-vibration rubber products - Google Patents

Description

The present invention relates to a rubber composition, a rubber composition for a vibration-proof rubber product, and a vibration-proof rubber product.

Anti-vibration rubber is placed in a portion that is a source of vibration and noise in order to improve comfort during boarding in various vehicles such as automobiles. In order to reduce the intrusion of vibration and noise into the room, for example, for an engine that is the main source of vibration and noise, anti-vibration rubber is used for components such as torsional dampers, engine mounts, and muffler hangers. This absorbs the vibration when the engine is driven, and reduces the intrusion of vibration and noise into the room and the diffusion of noise to the surrounding environment.

As the basic characteristics of such anti-vibration rubber, strength characteristics for supporting heavy objects such as engines and anti-vibration performance for absorbing and suppressing the vibration have been required. Further, when it is used in a high temperature environment such as an engine room, it is required to have excellent strength characteristics, low dynamic magnification and excellent vibration isolation performance, as well as excellent compression set characteristics. ..
Further, regarding the rubber composition used for the anti-vibration rubber product, in consideration of the manufacturability, it has been desired to improve the processability (particularly, scorch time) of the rubber composition in addition to the above-mentioned performance.

Many studies have been made on technologies for improving compression set characteristics while maintaining rubber physical properties, but those that achieve both compression set characteristics and scorch time at a high level are still being developed. There wasn't.

Therefore, an object of the present invention is to provide a rubber composition and a rubber composition for a vibration-proof rubber product, which are excellent in compression set characteristics and scorch time. Another object of the present invention is to provide a vibration-proof rubber product having excellent compression set.

The present inventors have conducted diligent research to achieve the above object. Then, they have found that by containing zinc fatty acid having a specific structure in the rubber composition, the compression set characteristics can be greatly improved and the scorch time can be improved (the scorch time can be lengthened).

（ここで、Ｒ^ａは炭素数1〜6の炭化水素基であり、Ｒ^ｂは炭素数1〜6の炭化水素基であり、Ｒ^ａ及びＲ^ｂはそれぞれ独立しており、同一であっても異なっていてもよい。）
上記構成により、圧縮永久歪特性及びスコーチタイムを向上できる。 That is, the rubber composition of the present invention contains a rubber component containing natural rubber and
It is characterized by containing zinc fatty acid having the following structural formula.

(Here, ^Ra is a hydrocarbon group having 1 to 6 carbon atoms, R ^b is a hydrocarbon group having 1 to 6 carbon atoms, and ^Ra and R ^b are independent and the same. May be different.)
With the above configuration, the compression set characteristics and the scorch time can be improved.

（ここで、Ｒ¹は、−S_x−C_nH_mCl_pであり、ｘは0以上の整数、ｎは1以上の整数、ｍは0以上の整数、ｐは1以上の整数であり、かつ、ｍ＋ｐ＝2ｎ＋1を満たす。Sは硫黄原子、Cは炭素原子、Hは水素原子、Clは塩素原子を示すが、Clはその他のハロゲン族元素に置換が可能である。また、上記式のＲ²、Ｒ³としては、水素、アミノ基、又は、炭素数１〜８の直鎖状、分岐状若しくは環状或いはその組み合わせの炭化水素基であり本置換基の位置と数には定めはない。）
縮永久歪特性及びスコーチタイムを、より向上できるためである。 Further, the rubber composition of the present invention preferably further contains an aromatic sulfonamide having the following structural formula.

(Here, R ¹ is −S _x −C _n H _m Cl _p , x is an integer of 0 or more, n is an integer of 1 or more, m is an integer of 0 or more, and p is an integer of 1 or more. , And m + p = 2n + 1. S is a sulfur atom, C is a carbon atom, H is a hydrogen atom, and Cl is a chlorine atom, but Cl can be replaced with another halogen group element. R ² and R ³ are hydrogen, amino groups, or linear, branched, cyclic, or a combination of hydrocarbon groups having 1 to 8 carbon atoms, and the position and number of the substituents are not specified. Absent.)
This is because the contractile permanent strain characteristics and the scorch time can be further improved.

Further, in the rubber composition of the present invention, it is preferable that the rubber component contains 55% by mass or less of high cis-containing isoprene rubber having a cis-1,4 bond content of 95% or more. This is because the compression set characteristics can be further improved.

Furthermore, in the rubber composition of the present invention, the zinc fatty acid is preferably zinc 2-ethylhexanoate. This is because better compression set characteristics and scorch time can be obtained.

Further, in the rubber composition of the present invention, the content of the fatty acid zinc is preferably 4 parts by mass or less with respect to 100 parts by mass of the rubber component. This is because better compression set characteristics and scorch time can be obtained without deteriorating other characteristics.

Further, in the rubber composition of the present invention, the aromatic sulfonamide is preferably N-phenyl-N- (trichloromethylthio) benzenesulfonamide. This is because the compression set characteristics and the scorch time can be further improved.

Furthermore, in the rubber composition of the present invention, the content of the aromatic sulfonamide is preferably 0.1 to 4 parts by mass with respect to 100 parts by mass of the rubber component. This is because the compression set characteristics and the scorch time can be further improved without deteriorating other characteristics.

Further, the rubber composition of the present invention preferably further contains carbon black having a DBP oil absorption amount of 125 ml / 100 g or less and an iodine adsorption amount of 85 g / kg or less. This is because more excellent compression set characteristics can be obtained.

The rubber composition for a vibration-proof rubber product of the present invention is characterized by comprising the rubber composition of the present invention.
With the above configuration, the compression set characteristics and the scorch time can be improved.

The anti-vibration rubber product of the present invention is characterized by using the above-mentioned rubber composition for anti-vibration rubber products.
With the above configuration, excellent compression set characteristics can be realized.

According to the present invention, it is possible to provide a rubber composition and a rubber composition for a vibration-proof rubber product, which are excellent in compression set characteristics and scorch time. Further, according to the present invention, it is possible to provide a vibration-proof rubber product having excellent compression set characteristics.

<Rubber composition>
An embodiment of the rubber composition of the present invention will be described in detail below.
The rubber composition of the present invention is a rubber composition containing a rubber component containing natural rubber and a fatty acid zinc having a specific structure.

(Rubber component)
The rubber component contained in the rubber composition of the present invention contains natural rubber (hereinafter, may be referred to as NR).

Here, the rubber component may be 100% natural rubber, but the content of the natural rubber may be 40 to 90% by mass in order to further improve the compression set characteristics and the scorch time. It is preferably 45 to 80% by mass, more preferably 45 to 80% by mass.
The type of the natural rubber is not particularly limited, and a known one can be appropriately selected. For example, RSS (Ribbed smoked sheets), TSR (Technically Specified Rubber) and the like can be used.

In addition to the above rubber components, other rubbers such as synthetic rubber may be used in combination as long as the object of the present invention is not impaired. Specific examples thereof include isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), ethylene-propylene-diene ternary copolymer (EPDM), butyl rubber (IIR), butyl halide rubber, and the like. Synthetic rubbers such as butyl bromoized rubber, chloroprene rubber, isobutylene-isoprene rubber, acrylonitrile-butadiene rubber, silicone rubber, acrylic rubber, epoxidized natural rubber, and acrylate butadiene rubber, and those with modified molecular chain ends of synthetic rubber are mentioned. This can be done, and one or more of these can be appropriately selected and used.

Further, the rubber component preferably contains isoprene rubber among the other rubbers described above, and among the isoprene rubbers, the high cis-containing isoprene rubber having a cis-1,4 bond content of 95% or more is contained. It is more preferable to do so. This is because the compression set characteristics of the rubber composition of the present invention can be further improved.
The content of the high cis-containing isoprene rubber in the rubber component is not particularly limited, but it is possible to obtain more excellent compression set characteristics while maintaining the above-mentioned basic characteristics such as strength and dynamic magnification. From the above, it is preferably 55% by mass or less, and more preferably 5 to 55% by mass. If the content of the high cis-containing isoprene rubber in the rubber component exceeds 55% by mass, the basic characteristics such as strength and dynamic magnification may be deteriorated.

（ここで、Ｒ^ａは炭素数1〜6の炭化水素基であり、Ｒ^ｂは炭素数1〜6の炭化水素基であり、Ｒ^ａ及びＲ^ｂはそれぞれ独立しており、同一であっても異なっていてもよい。）
上記構造の脂肪酸亜鉛を含むことによって、ゴム組成物の圧縮永久歪特性を大きく向上できる。また、該脂肪酸亜鉛を含むことによって、スコーチタイムについても大きく改善できる。 (Fatty acid zinc)
The rubber composition of the present invention contains a fatty acid zinc having the following structural formula.

(Here, ^Ra is a hydrocarbon group having 1 to 6 carbon atoms, R ^b is a hydrocarbon group having 1 to 6 carbon atoms, and ^Ra and R ^b are independent and the same. May be different.)
By containing the fatty acid zinc having the above structure, the compression set characteristics of the rubber composition can be greatly improved. In addition, the scorch time can be greatly improved by including the fatty acid zinc.

Here, the type of the fatty acid zinc may be any one having the above structural formula, and is not particularly limited. For example, zinc 2-ethylhexanoate, zinc 2-methylhexanoate, zinc 2-propylhexanoate and the like can be mentioned. As for these fatty acid zinc, only one kind may be contained in the rubber composition, or a plurality of kinds may be contained.
Among them, zinc 2-ethylhexanoate is preferably used as the fatty acid zinc from the viewpoint of obtaining more excellent compression set characteristics and scorch time. The specific product of zinc 2-ethylhexanoate is not particularly limited, and commercially available products can be used. Further, the zinc 2-ethylhexanoate can be used as it is, or can be supported on silica or the like.

Further, the content of the fatty acid zinc is preferably 4 parts by mass or less with respect to 100 parts by mass of the rubber component. This is because better compression set characteristics and scorch time can be obtained. When the content of the fatty acid zinc exceeds 4 parts by mass with respect to 100 parts by mass of the rubber component, excellent compression set and scorch time can be obtained, but other properties may be deteriorated.
Further, from the same viewpoint, the content of the fatty acid zinc is more preferably 0.5 to 4 parts by mass and particularly preferably 1 to 3 parts by mass with respect to 100 parts by mass of the rubber component.

（ここで、Ｒ¹は、−S_x−C_nH_mCl_pであり、ｘは0以上の整数、ｎは1以上の整数、ｍは0以上の整数、ｐは1以上の整数であり、かつ、ｍ＋ｐ＝2ｎ＋1を満たす。Sは硫黄原子、Cは炭素原子、Hは水素原子、Clは塩素原子を示すが、Clはその他のハロゲン族元素に置換が可能である。また、上記式のＲ²、Ｒ³としては、水素、アミノ基、又は、炭素数１〜８の直鎖状、分岐状若しくは環状或いはその組み合わせの炭化水素基であり本置換基の位置と数には定めはない。）
ゴム組成物中に、上記構造式を有する芳香族スルホンアミドを含むことによって、ゴム組成物の圧縮永久歪特性をより向上できることに加え、強度や動倍率等の基本特性についてもさらに向上できる。 (Aromatic sulfonamide)
Further, the rubber composition of the present invention preferably further contains an aromatic sulfonamide having the following structural formula in addition to the above-mentioned rubber component and fatty acid zinc.

(Here, R ¹ is −S _x −C _n H _m Cl _p , x is an integer of 0 or more, n is an integer of 1 or more, m is an integer of 0 or more, and p is an integer of 1 or more. , And m + p = 2n + 1. S is a sulfur atom, C is a carbon atom, H is a hydrogen atom, and Cl is a chlorine atom, but Cl can be replaced with another halogen group element. R ² and R ³ are hydrogen, amino groups, or linear, branched, cyclic, or a combination of hydrocarbon groups having 1 to 8 carbon atoms, and the position and number of the substituents are not specified. Absent.)
By including the aromatic sulfonamide having the above structural formula in the rubber composition, in addition to further improving the compression set characteristics of the rubber composition, the basic characteristics such as strength and dynamic magnification can be further improved.

Examples of the aromatic sulfonamide include N-phenyl-N- (monochromomethylthio) toluenesulfonamide, N-phenyl-N- (dichloromethylthio) toluenesulfonamide, and N-phenyl-N- (dichloromethylthio) toluenesulfonamide. Amid, N-phenyl-N- (monochromelomethylthio) toluenesulfonamide, N-phenyl-N- (trichloromethylthio) benzenesulfonamide, N-phenyl-N- (dichloromethylthio) benzenesulfonamide, N-phenyl-N- Examples thereof include (trichloromethylthio) benzenesulfonamide, N-phenyl-N- (trichloroethylthio) benzenesulfonamide, N-phenyl-N- (trichloropropylthio) benzenesulfonamide and the like.

なお、前記Ｎ−フェニル−Ｎ−（トリクロロメチルチオ）ベンゼンスルホンアミドの具体的な商品については、特に限定はされないが、例えば、「Ｖｕｌｋａｌｅｎｔ Ｅ／Ｃ」（ＬＡＮＸＥＳＳ社製）等が挙げられる。 Among the above-mentioned aromatic sulfonamides, it is preferable to use N-phenyl-N- (trichloromethylthio) benzenesulfonamide represented by the following formula. This is because the basic characteristics such as strength and dynamic magnification and the compression set characteristics can be further improved.

The specific product of the N-phenyl-N- (trichloromethylthio) benzenesulfonamide is not particularly limited, and examples thereof include "Vulkalent E / C" (manufactured by LANXESS).

The content of the aromatic sulfonamide is preferably 0.1 to 4 parts by mass with respect to 100 parts by mass of the rubber component from the viewpoint of further improving the compression set and the scorch time.
If the content of the aromatic sulfonamide is less than 0.1 parts by mass with respect to 100 parts by mass of the rubber component, sufficient compression set characteristics may not be obtained, while the content is 100 parts by mass of the rubber component. If it exceeds 4 parts by mass with respect to parts by mass, other characteristics such as heat aging resistance and low temperature characteristics may be deteriorated.

(Other ingredients)
In addition to the rubber component, fatty acid zinc and aromatic sulfonamide described above, the rubber composition of the present invention contains carbon black, a filler, a vulcanization accelerator and vulcanization as long as the object of the present invention is not impaired. Additives such as agents, vulcanization accelerators, oils, antioxidants, antioxidants, fillers, foaming agents, plasticizers, lubricants, tackifiers, UV absorbers and the like can be included.

Here, as the carbon black, those normally used in the rubber industry can be used, and the carbon black is not particularly limited, but in the present invention, the DBP (dibutyl phthalate) oil absorption amount is 125 ml / 100 g. Carbon black having the following value and an iodine adsorption amount of 85 g / kg or less can be preferably used. This is because the pane effect can be reduced and the dynamic magnification can be kept lower. Further, the lower limit values of the DBP oil absorption amount and the iodine adsorption amount are not particularly limited, but are 20 ml / 100 g and 5 g / kg, respectively, from the viewpoint of surely obtaining the above-mentioned effect of keeping the dynamic ratio low. preferable.
The DBP oil absorption amount and iodine adsorption amount are measured in accordance with JIS K 6217 (1997). Further, these carbon blacks may be used alone or in combination of two or more.

Further, the content of the carbon black is preferably 5 to 100 parts by mass, preferably 15 to 60 parts by mass with respect to 100 parts by mass of the rubber component, from the viewpoint of further improving the compression set of the rubber composition. It is more preferable that it is a part.

The filler is not particularly limited, and fillers such as silica, white carbon, fine magnesium silicate, heavy calcium carbonate, magnesium carbonate, clay, and talc can be appropriately used.

As the vulcanizing agent, conventionally known ones can be used, and the vulcanizing agent is not particularly limited, but in the present invention, sulfur can be preferably used. This is because various characteristics of rubber can be further improved. When the sulfur is contained, the sulfur content is preferably 0.1 to 1.5 parts by mass, and more preferably 0.2 to 1.0 parts by mass with respect to 100 parts by mass of the rubber component. If the content exceeds 1.5 parts by mass, the heat aging property may be deteriorated.

Further, as the vulcanizing agent, a bismaleimide compound can also be preferably used. This is to improve heat resistance and prevent vulcanization from returning at high temperatures.
Regarding the types of the bismaleimide compounds, for example, N, N'-o-phenylene bismaleimide, N, N'-m-phenylene bismaleimide, N, N'-p-phenylene bismaleimide, N, N'-( Illustrate 4,4'-diphenylmethane) bismaleimide, 2,2-bis- [4- (4-maleimidephenoxy) phenyl] propane, bis (3-ethyl-5-methyl-4-maleimidephenyl) methane, and the like. Can be done. In the present invention, N, N'-m-phenylene bismaleimide and N, N'-(4,4'-diphenylmethane) bismaleimide and the like can be mentioned.
The bismaleimide compound may be used alone or in combination of two or more. The content is preferably 0.2 to 5.0 parts by mass with respect to 100 parts by mass of the rubber component. If the blending amount of the bismaleimide compound is less than 0.2 parts by mass, the heat aging property, compression set, and the like may deteriorate, while if it exceeds 5.0 parts by mass, the tensile physical properties (elongation, strength), durability, etc. may deteriorate. May get worse

As the vulcanization accelerator, known ones can be used and are not particularly limited. For example, 2-mercaptobenzothiazole, dibenzothiazyl disulfide, N-cyclohexyl-2-benzothiadylsulfeneamide, Nt-butyl-2-benzothiadylsulfenamide, N-t-butyl-2-benzo. Benzothiazole-based sulphurization accelerators such as thiazyl sulphenamide; guanidine-based sulphurization accelerators such as diphenylguanidine; tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetradodecylthiuram disulfide, tetraoctylthiuram disulfide, Thiram-based sulfide accelerators such as tetrabenzyl thiuram disulfide and dipentamethylene thiuram tetrasulfide; dithiocarbamate-based agents such as zinc dimethyldithiocarbamate; and other zinc dialkyldithiophosphates.

As the vulcanization accelerator, one or more of sulfenamide type, thiuram type, thiazole type, guanidine type, dithiocarbamate type and the like can be used in combination, and for adjusting the vulcanization behavior (rate), etc. It is preferable to combine a thiuram-based and / or thiazole-based vulcanization accelerator having a relatively high vulcanization promoting ability with a guanidine-based and / or sulfenamide-based vulcanization accelerator having a relatively medium to low vulcanization promoting capacity. Will be adopted. Specifically, a combination of tetramethylthiuram disulfide and N-cyclohexyl-2-benzothiazil sulfenamide, a combination of tetrabutylthium disulfide and N-t-butyl-2-benzothiazil sulfenamide, dibenzo Examples thereof include a combination of thiazyl disulfide and diphenylguanidine.
However, the combination of the vulcanization accelerators is not limited to the above-mentioned combination. The total amount of the vulcanization accelerator is preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

Examples of the vulcanization accelerator include zinc oxide (ZnO) and fatty acids. The fatty acid may be saturated or unsaturated, linear or branched fatty acid, and the number of carbon atoms of the fatty acid is not particularly limited, but for example, a fatty acid having 1 to 30, preferably 15 to 30 carbon atoms. More specifically, cyclohexanoic acid (cyclohexanecarboxylic acid), naphthenic acid such as alkylcyclopentane having a side chain, hexanoic acid, octanoic acid, decanoic acid (including branched carboxylic acid such as neodecanoic acid), dodecanoic acid, tetradecane. Examples thereof include saturated fatty acids such as acid, hexadecanoic acid and octadecanoic acid (stearic acid), unsaturated fatty acids such as methacrylic acid, oleic acid, linoleic acid and linolenic acid, and resin acids such as rosin, tall oil acid and avietic acid. These may be used alone or in combination of two or more. In the present invention, zinc oxide and stearic acid can be preferably used. The content of these auxiliaries is preferably 1 to 10 parts by mass, and more preferably 2 to 7 parts by mass with respect to 100 parts by mass of the rubber component. If the content exceeds 10 parts by mass, workability may be deteriorated and the dynamic ratio may be deteriorated, and if it is less than 1 part by mass, vulcanization may be delayed.

Known oils can be used, and the oil is not particularly limited, but specifically, process oils such as aromatic oils, naphthenic oils and paraffin oils, vegetable oils such as coconut oil, and synthetic oils such as alkylbenzene oils. Castor oil etc. can be used.
In the present invention, naphthenic oil can be preferably used. These can be used alone or in combination of two or more. The content of the oil is not particularly limited, but can be approximately 2 to 80 parts by mass with respect to 100 parts by mass of the rubber component. If the blending amount deviates from the above range, the kneading workability may deteriorate. When the oil-expanded rubber is used as the rubber component, the total amount of the oil contained in the rubber and the oil separately added at the time of mixing may be within the above range.

As the anti-aging agent, known ones can be used and are not particularly limited. For example, a phenol-based anti-aging agent, an imidazole-based anti-aging agent, an amine-based anti-aging agent, and the like can be mentioned. The content of these anti-aging agents is usually 1 to 10 parts by mass, preferably 2 to 7 parts by mass with respect to 100 parts by mass of the rubber component. The anti-aging agent may be used alone or in combination of two or more.

When obtaining the rubber composition of the present invention, there is no particular limitation on the method of blending each component described above, and all the component raw materials may be blended at once and kneaded, or divided into two or three steps. Each component may be mixed and kneaded. For kneading, a known kneader such as a roll, an internal mixer, or a Banbury rotor can be used. Further, when molding into a sheet shape, a strip shape, or the like, a known molding machine such as an extrusion molding machine or a press machine may be used.

The vulcanization conditions for curing the rubber composition are not particularly limited. For example, vulcanization conditions at 140-180 ° C. for 5-120 minutes can be employed.

<Rubber composition for anti-vibration rubber products>
The rubber composition for a vibration-proof rubber product of the present invention is characterized by comprising the above-mentioned rubber composition of the present invention.
The rubber composition for a vibration-proof rubber product of the present invention can realize excellent compression set characteristics and scorch time by providing the above structure.

<Vibration-proof rubber products>
The anti-vibration rubber product of the present invention is characterized by using the above-mentioned rubber composition for an anti-vibration rubber product of the present invention.
By using the rubber composition for anti-vibration rubber products of the present invention, excellent compression set characteristics can be realized.
The anti-vibration rubber product is a product used in a state where the above-mentioned rubber composition and a metal material are in contact with each other (integrated). For example, for vehicles (automobiles, trucks, buses, trains, etc.) Used for construction machinery such as excavators) and mechanical equipment (equipment and equipment with elevators and drives). Further, as a method of integrating the rubber of the anti-vibration rubber product with the metal material, for example, a non-adhesive type method such as press-fitting the rubber into the metal material, or rubber is attached to the metal material via an adhesive. Examples include a method of adhering.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

(Examples / Reference Examples 1 to 12, Comparative Examples 1 to 4)
Rubber compositions to be used as samples were prepared according to the component compositions shown in Tables 1 to 4.

(Evaluation)
The rubber composition of each of the above samples was vulcanized and cured under predetermined conditions as a sample, and (1) compression set and (2) Mooney scorch time were evaluated.

(1) Compressive permanent strain For each sample, the compressive permanent strain was measured in accordance with JIS K 6262 under heating temperature conditions of 100 ° C. and 72 hours.
Regarding the measured compression set, the exponential value when the value of the compression set of Comparative Example 1 in Table 1, Comparative Example 2 in Table 2, Comparative Example 3 in Table 3, and Comparative Example 4 in Table 4 is set to 100. Displayed with. As for the exponential value, the smaller the value, the smaller the compression set and the better the result. In addition, regarding the results, it is judged that there is an actual effect when there is an improvement of 5% or more.

(2) Mooney Scorch Time For each sample, in accordance with JIS K 6300-1: 2001 "How to determine viscosity and scorch time with Mooney viscometer", measure the rubber composition at 130 ° C and start residual heat. The Mooney scorch time was obtained by measuring the time (minutes) until the value increased by 5 units from the minimum value Vm.
Regarding the measured Mooney scoach time, the index value when the Mooney scoach time value of Comparative Example 1 in Table 1, Comparative Example 2 in Table 2, Comparative Example 3 in Table 3, and Comparative Example 4 in Table 4 is set to 100. Displayed with. As for the index value, the larger the index value, the longer the scorch time and the better the processing stability. In addition, regarding the results, it is judged that there is an actual effect when there is an improvement of 5% or more.

* 1: "RSS # 4"
* 2: JSR "IR2200", cis-1,4 bond content: 95% or more
* 3: Tokai Carbon "Seast FM", FEF grade carbon black, DBP oil absorption: 160ml / 100g, iodine adsorption: 35g / kg
* 4: Asahi Carbon "Asahi Thermal", FT grade carbon black, DBP oil absorption: 28ml / 100g, iodine adsorption: 27g / kg
* 5: Mitsubishi Chemical "Dia Black H", HAF grade carbon black, DBP oil absorption: 105ml / 100g, iodine adsorption: 81g / kg
* 6: "Stearic acid 50S" manufactured by New Japan Chemical Co., Ltd.
* 7: "No. 3 Zinc Oxide" manufactured by HakusuiTech Co., Ltd.
* 8: Seiko Kagaku "Santite S"
* 9: "Nocrack 6C" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., N-phenyl-N'-(1,3-dimethylbutyl) -p-phenylenediamine
* 10: "Structor ZEH" made by Stratktor
* 11: "Sun there 4240" made by SUN REFING AND MARKETING COMPANY
* 12: "Powdered sulfur" manufactured by Tsurumi Chemical Co., Ltd.
* 13: Ouchi Shinko Kagaku Co., Ltd. product "Barnock PM", N, N'-m-phenylene bismaleimide
* 14: "Axel TBT-P" manufactured by Kawaguchi Chemical Industry
* 15: "Noxeller NS" manufactured by Ouchi Shinko Kagaku Co., Ltd.
* 16: LANXESS "Vulkalent E / C"

From the results in Table 1, for each example containing zinc 2-ethylhexanoate in the rubber composition, the compression set and Mooney scorch time were higher than those of Comparative Example 1 not containing zinc 2-ethylhexanoate. It was found that all of them showed great and excellent results.
From the results in Tables 2 and 3, even when carbon blacks of different grades were used, zinc 2-ethylhexanoate was contained in the examples containing zinc 2-ethylhexanoate in the rubber composition. It was found that the results were significantly superior in both the compression set and the Mooney scorch time, as compared with the non-comparative example.
From the results in Table 4, even when the high cis-containing isoprene rubber is contained as the rubber component, zinc 2-ethylhexanoate is contained in the example containing zinc 2-ethylhexanoate in the rubber composition. It was found that both the compression set and the Mooney scorch time were significantly superior to those of Comparative Example 4.

According to the present invention, it is possible to provide a rubber composition and a rubber composition for a vibration-proof rubber product, which are excellent in compression set characteristics and scorch time.

Claims (9)

Rubber components containing natural rubber and
Fatty acid zinc having the following structural formula and

(Here, ^Ra is a hydrocarbon group having 1 to 6 carbon atoms, R ^b is a hydrocarbon group having 1 to 6 carbon atoms, and ^Ra and R ^b are independent and the same. May be different.)
Aromatic sulfonamide having the following structural formula and

(Here, R ¹ is −S _x −C _n H _m Cl _p , x is an integer of 0 or more, n is an integer of 1 or more, m is an integer of 0 or more, and p is an integer of 1 or more. , And m + p = 2n + 1. S is a sulfur atom, C is a carbon atom, H is a hydrogen atom, and Cl is a chlorine atom, but Cl can be replaced with another halogen group element. R ² and R ³ are hydrogen, amino groups, or linear, branched, cyclic, or a combination of hydrocarbon groups having 1 to 8 carbon atoms, and the position and number of the substituents are not specified. Absent.)
A rubber composition comprising. The rubber composition according to claim 1 , wherein the rubber component contains 55% by mass or less of a high cis-containing isoprene rubber having a cis-1,4 bond content of 95% or more. The rubber composition according to claim 1 or 2 , wherein the fatty acid zinc is zinc 2-ethylhexanoate. The rubber composition according to any one of claims 1 to 3 , wherein the content of the fatty acid zinc is 4 parts by mass or less with respect to 100 parts by mass of the rubber component. The rubber composition according to any one of claims 1 to 4 , wherein the aromatic sulfonamide is N-phenyl-N- (trichloromethylthio) benzenesulfonamide. The rubber composition according to any one of claims 1 to 5 , wherein the content of the aromatic sulfonamide is 0.1 to 4 parts by mass with respect to 100 parts by mass of the rubber component. The rubber composition according to any one of claims 1 to 6 , further comprising carbon black having a DBP oil absorption amount of 125 ml / 100 g or less and an iodine adsorption amount of 85 g / kg or less. A rubber composition for a vibration-proof rubber product, which comprises the rubber composition according to any one of claims 1 to 7 . An anti-vibration rubber product, which comprises using the rubber composition for an anti-vibration rubber product according to claim 8 .