JP2007063480A - Rubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition that has high elasticity and high fracture characteristics. <P>SOLUTION: The rubber composition can be obtained by adding (a) 1 to 30 pts.wt. of amino resin represented by general formula (1) (wherein n is an integer of 1 or more, R<SB>1</SB>is H or an amino group, R<SB>2</SB>is H, an amino group, a 1 to 20C alkyl group, a 3 to 20C cycloalkyl group, or a 6 to 20C aryl group) and (b) 1 to 20 wt.% of a methylene donor, based on the amino resin, based on 100 pts.wt. of diene rubber. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rubber composition and a tire using the rubber composition, and more particularly to a rubber composition having a high elastic modulus and a high breaking property.

  Conventionally, as a means of increasing the elasticity of rubber, there are a method of increasing the amount of filler such as carbon black and a method of increasing the amount of crosslinking agent such as sulfur. There is a problem. As a means for increasing the elasticity of rubber while suppressing a decrease in breaking properties, a method of blending an unmodified phenol resin or a phenol resin modified with tall oil, cashew oil or the like is known (Patent Documents 1 and 2). Further, a rubber having higher elasticity and higher elongation at cutting is desired.

JP-A-57-57734 JP 05-98080 A

  Therefore, an object of the present invention is to provide a rubber composition that has higher elasticity than the prior art and suppresses a decrease in elongation at the time of cutting.

（式中、ｎは１以上の整数、Ｒ₁は水素又はアミノ基であり、Ｒ₂は水素、アミノ基、炭素数１〜２０個のアルキル基、炭素数３〜２０個のシクロアルキル基、又は炭素数６〜２０個のアリール基である。）
で表わされるアミノ樹脂１〜３０重量部、及び（ｂ）前記アミノ樹脂の１〜２０重量％のメチレン供与体を配合してなるゴム組成物が提供される。 According to the present invention, (a) the following general formula 1:

(In the formula, n is an integer of 1 or more, R ₁ is hydrogen or an amino group, R ₂ is hydrogen, an amino group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, Or an aryl group having 6 to 20 carbon atoms.)
A rubber composition comprising 1 to 30 parts by weight of an amino resin represented by formula (b) and (b) 1 to 20% by weight of a methylene donor based on the amino resin is provided.

  In the present invention, it has been found that a rubber composition having a high elastic modulus and a high elongation at cutting can be obtained by using a specific amino resin and a methylene donor in combination.

（式中、ｎは１以上の整数、Ｒ₁は水素又はアミノ基であり、Ｒ₂は水素、アミノ基、炭素数１〜２０個のアルキル基、炭素数３〜２０個のシクロアルキル基、又は炭素数６〜２０個のアリール基である。）
で示される重合体であり、好ましくは、ＪＩＳ Ｋ２２０７の環球法による軟化点で１３０℃以下、好ましくは常温で液体〜１３０℃の軟化点であるアミノ樹脂である。 In the rubber composition of the present invention, the amino resin used as a compounding agent has the following general formula 1:

(In the formula, n is an integer of 1 or more, R ₁ is hydrogen or an amino group, R ₂ is hydrogen, an amino group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, Or an aryl group having 6 to 20 carbon atoms.)
Preferably, it is an amino resin having a softening point of 130 ° C. or less, preferably a liquid to 130 ° C. softening point by a ring and ball method of JIS K2207.

Examples of the alkyl group having 1 to 20 carbon atoms of the substituent R ₂ in the amino resin include, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, Decyl, undecyl, dodecyl, isobutyl, isopentyl, neopentyl, isohexyl, neohexyl, isooctyl, t-butyl, t-pentyl, t-octyl, vinyl, allyl, isopropenyl Group, benzyl group, phenethyl group, diphenylmethyl group, propenyl group, 2-methylallyl group, 2-butenyl group and the like, and examples of the cycloalkyl group having 3 to 20 carbon atoms include, for example, cyclohexyl group , Cyclopropyl group, cyclopentyl group, cyclooctyl group, 2-methylcyclohexyl group, 2- Chill cyclohexyl, 2-cyclopropyl hexene-1-yl group, cyclohexanyl group, 1,3-cyclohexadienyl group. Furthermore, as the aryl group having 6 to 20 carbon atoms, phenyl group, naphthyl group, tolyl group, xylyl group, cumenyl group, mesityl group, methylphenyl group, ethylphenyl group, propylphenyl group, t-butylphenyl group, And biphenyl group.

  In addition, the amino resin is available as, for example, trade names PR-TR-01, PR-TR-02 (both manufactured by Sumitomo Bakelite Co., Ltd.) and the like. Also, for example, 93 kg of aniline, 93 L of industrial hydrochloric acid, and It can also be obtained by adding 150 L of formalin to aniline hydrochloride solution obtained using 930 L of water and reacting for 1 to 2 hours, followed by neutralization with 5% sodium hydroxide solution, filtration, washing with water and drying.

  Further, as the methylene donor compounded in the rubber composition of the present invention, hexamethylenetetramine and methylolated melamine derivatives can be used, and as the methylolated melamine derivatives, hexamethoxymethylol melamine, pentamethoxymethylol melamine, hexamethoxy Methylmelamine, hexaethoxymethylmelamine, hexakis- (methoxymethyl) melamine, N, N ′, N ″ -trimethyl-N, N ′, N ″ -trimethylolmelamine, N, N ′, N ″ -trimethylolmelamine, N-methylol melamine N, N ′-(methoxymethyl) melamine, N, N ′, N ″ -tributyl-N, N ′, N ″ -trimethylol melamine, etc. are used, and these are used alone or in combination. Among these, in particular, hexamethylenetetramine, hexame Xylene melamine, the use of such pentamethoxy methylol melamine is preferred.

  The rubber composition of the present invention contains 1 to 30 parts by weight, preferably 1 to 25 parts by weight of the amino resin, and 1 to 20% by weight, preferably 1 to 100 parts by weight of the diene rubber. An amount corresponding to ˜15% by weight of the methylene donor is used in combination. If the amount of the amino resin is less than 1 part by weight, the desired effect cannot be exhibited. On the other hand, if it exceeds 30 parts by weight, the rubber flexibility is reduced, which is not preferable. Further, when the blending amount of the methylene donor is less than 1% by weight of the amino resin, the intended effect cannot be exhibited, and conversely when it exceeds 20% by weight of the amino resin, This is not preferable because the action as a vulcanization accelerator becomes strong and adversely affects the crosslinking system.

  Examples of the diene rubber in the present invention include natural rubber (NR), polyisoprene rubber (IR), various styrene-butadiene copolymer rubbers (SBR), various polybutadiene rubbers (BR), and acrylonitrile-butadiene copolymer rubber (NBR). ), Diene-based synthetic rubbers such as chloroprene rubber (CR) can be used alone or in combination of two or more thereof.

  The rubber composition according to the present invention further includes ordinary vulcanization or crosslinking agents, vulcanization or crosslinking accelerators, reinforcing agents such as fatty acids, metal oxides, carbon black and silica, silane coupling agents, various oils, Anti-aging agents, fillers, plasticizers, and other various compounding agents compounded for general rubber or tire rubber can be compounded, and such compounding agents are kneaded by a general method to obtain a rubber composition, It can be vulcanized or crosslinked. The compounding amounts of these compounding agents can be set to conventional general compounding amounts as long as the object of the present invention is not violated.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further, it cannot be overemphasized that the scope of the present invention is not limited to these Examples.

Preparation of Test Sample Components except for the vulcanization accelerator, sulfur and methylene donor in the formulation shown in Table 1 below were kneaded for 5 minutes with a 1.8 L closed mixer to obtain a master batch. This master batch was kneaded with a vulcanization accelerator, sulfur and a methylene donor with an 8-inch open roll to obtain a rubber composition. Next, this rubber composition was press vulcanized at 160 ° C. for 20 minutes in a 15 cm × 15 cm × 0.2 cm mold to produce a target test piece (rubber sheet), which was subjected to the following physical property tests. .

Test Method 1) Hardness: The hardness at 20 ° C. was measured using a type A durometer according to JIS K6253. The measurement results are indicated by an index with Comparative Example 1 being 100. It shows that hardness is so high that a numerical value is large.
2) M100: Tensile stress at 100% elongation was measured using a dumbbell No. 3 type test piece in accordance with JIS K6251. The measurement results are indicated by an index with Comparative Example 1 being 100. It shows that tensile stress is so large that a numerical value is large.
3) Elongation at break (E _B ): Elongation at break was measured according to JIS K6251. The measurement results are indicated by an index with Comparative Example 1 being 100. The larger the value, the greater the elongation at cutting.
4) Storage elastic modulus (E ′): Using a viscoelasticity spectrometer manufactured by Toyo Seiki Seisakusho Co., Ltd., the storage elastic modulus was obtained under the conditions of 20 ° C., initial strain: 10%, amplitude: ± 2%, and frequency 20 Hz. It was measured. The measurement results are indicated by an index with Comparative Example 1 being 100. A larger index indicates a higher storage modulus.

Examples 1-3 and Comparative Examples 1-3
The results are shown in Table 1.

  According to the above results, it can be seen that the rubber composition of the present invention is excellent in all of the above physical properties.

  Therefore, the rubber composition of the present invention is extremely useful as a tire rubber composition.

Claims (3)

For 100 parts by weight of diene rubber
(A) The following general formula 1:

(In the formula, n is an integer of 1 or more, R ₁ is hydrogen or an amino group, R ₂ is hydrogen, an amino group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, Or an aryl group having 6 to 20 carbon atoms.)
1 to 30 parts by weight of an amino resin represented by the formula: (b) A rubber composition comprising 1 to 20% by weight of a methylene donor based on the amino resin.   The rubber composition according to claim 1, wherein the amino resin has a softening point of 130 ° C. or less by a ring and ball method.   A tire using the rubber composition according to claim 1.