JP2002338733A - Rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition that is excellent in low heat generation and grip performance without deteriorating processability and wear resistance. SOLUTION: The rubber composition comprises carbon black contained in an amount of 5-150 pts.wt. per 100 pts.wt. natural rubber and/or diene-based synthetic rubber and a polyoxyalkylene glycol compound represented by formula (1) or formula (2) blended in an amount of 0.1-25 pts.wt. per 100 pts.wt. carbon black (in the formulae, R<1> and R<3> are each independently an alkyl group, a benzyl group or an aryl group, all of which may be the same or different, R<2> is a methylene group, an ethylene group, a propylene group or a tetramethylene group, all of which may be the same or different; R<4> is a 1-22C alkyl or aryl group; and n is a positive integer of not more than 100).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition, and more particularly to a rubber composition for a tire.

[0002]

2. Description of the Related Art In recent years, the characteristics required for automobile tires are various, such as low fuel consumption, driving stability, abrasion resistance, and riding comfort. Various improvements have been made to improve these performances.

[0003] Of these performances, particularly, the grip performance and the rolling resistance characteristics of the tire are all characteristics relating to hysteresis loss of rubber. Generally, when the hysteresis loss is increased, the grip force is increased and the braking performance is improved, but the rolling resistance is increased and the fuel efficiency is increased. As described above, since the grip performance and the rolling resistance characteristic are in a contradictory relationship, various rubber compositions for tires have been proposed in order to simultaneously satisfy both characteristics.

For example, in a rubber composition for a tire, since a polymer and carbon black greatly affect both properties, when a styrene-butadiene copolymer is used as a polymer, the content of bound styrene, butadiene moiety The content of the 1, 2 bond is appropriately selected to improve both the rolling resistance characteristics and the grip performance. On the other hand, for carbon black, techniques such as reducing the carbon black filling amount and increasing the particle size of carbon black are used, but in any case, both low heat generation and reinforcement and wear resistance are compatible. Is difficult, and in reality, a type of carbon black in which the activity of the carbon black particle surface is optimized is currently used.

On the other hand, many methods using silica for the purpose of reducing heat generation have been reported. However, silica tends to agglomerate with each other due to hydrogen bonds of silanol groups, which are surface functional groups, and the dispersion of silica particles in rubber becomes insufficient, causing problems such as poor processability.

[0006] To solve these problems, silane coupling agents are used. The silane coupling agent binds to the silanol groups on the silica surface to prevent aggregation of the silica and improve processability.At the same time, the silica and polymer chemically bond with the silane coupling agent to reduce rolling resistance. It is considered. However, even if a silane coupling agent is used, a reduction in wear resistance is inevitable, and there is a problem that low heat build-up (rolling resistance characteristics) and sufficient improvement in wear resistance cannot be expected.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber composition having low heat build-up and excellent grip performance without deteriorating workability and abrasion resistance.

[0008]

Means for Solving the Problems As a result of intensive studies to improve the above problems, the use of a polyoxyalkylene glycol compound having a urethane bond makes it possible to reduce the rolling resistance without lowering the workability and wear resistance. And a method to satisfy the grip performance was developed.

That is, the present invention comprises 5-150 parts by weight of carbon black based on 100 parts by weight of natural rubber and / or a diene-based synthetic rubber, and 100 parts by weight of carbon black, and the following general formula (1) ) Or a rubber composition comprising 0.1 to 25 parts by weight of the polyoxyalkylene glycol compound represented by (2).

[0010]

Embedded image

Wherein R ¹ and R ³ are an alkyl group, a benzyl group or an aryl group, which may be the same or different. R ² is a methylene group, an ethylene group, a propylene group or R ⁴ is an alkyl group or an aryl group having 1 to 22 carbon atoms, and may be the same or different.
Is a positive integer of 100 or less. )

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The rubber composition of the present invention comprises a rubber component and carbon black and a polyoxyalkylene glycol compound having a urethane bond.

The rubber component used in the present invention is a natural rubber (NR) and / or a diene-based synthetic rubber. Examples of the diene-based synthetic rubber that can be used in the present invention include styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), and butyl rubber. (IIR), acrylonitrile-
Butadiene rubber (NBR) and the like may be mentioned, and one or more kinds may be contained in the rubber component used in the present invention.

[0015] The rubber composition of the present invention contains carbon black as a filler. Examples of carbon black that can be used in the present invention include HAF, ISAF, SA
Examples include F, FEF, and GPF, but are not particularly limited.

The compounding amount of carbon black is 5 to 150 parts by weight based on 100 parts by weight of the rubber component. If the compounding amount of carbon black is less than 5 parts by weight, sufficient reinforcing properties cannot be obtained, and if it exceeds 150 parts by weight, heat generation increases. From the viewpoint of reinforcement and low heat generation, the upper limit is preferably 120 parts by weight, more preferably 100 parts by weight, and the lower limit is 20 parts by weight.

The polyoxyalkylene glycol compound having a urethane bond used in the present invention is represented by the following general formula (1) or (2).

[0018]

Embedded image

In the formula, R ¹ and R ³ are an alkyl group, a benzyl group or an aryl group, all of which may be the same or different. As the alkyl group, an alkyl group having 1 to 6 carbon atoms is preferable.

R ² is a methylene group, ethylene group, propylene group or tetramethylene group, all of which may be the same or different.

R ⁴ is an alkyl or aryl group having 1 to 22 carbon atoms. Examples of the alkyl group having 1 to 22 carbon atoms include a methyl group, an ethyl group, a butyl group, a hexyl group, an octyl group, a lauryl group, a stearyl group, and an oleyl group.

N is a positive integer of 100 or less, preferably 95 or less. Further, n is preferably 6 or more. When n exceeds 100, the dispersing effect becomes insufficient, and 6
If it is less than 1, the volatility of the polyoxyalkylene glycol compound is high, and the workability tends to decrease.

The compounding amount of the polyoxyalkylene glycol compound is 0.1 to 25 parts by weight based on 100 parts by weight of the carbon black. When the blending amount of the polyoxyalkylene glycol compound is less than 0.1 part by weight, the improvement in grip performance aimed at by the present invention is not sufficient,
When the amount is more than the weight part, not only the effect corresponding to the increased amount cannot be obtained, but also adversely affects various physical properties after vulcanization. From the viewpoint of both grip performance and low heat generation, the upper limit is 20
More preferably, the amount is 15 parts by weight, more preferably 0.5 parts by weight, and even more preferably 1 part by weight.

Further, the rubber composition of the present invention may contain silica. The amount of silica is 100
The amount is preferably 5 to 100 parts by weight with respect to parts by weight. If the amount of silica is less than 5 parts by weight, the reinforcing effect tends to be small, and if it exceeds 100 parts by weight, workability tends to decrease. From the viewpoint of low heat generation and workability, the amount of silica
More preferably, the upper limit is 85 parts by weight, more preferably 65 parts by weight, and the lower limit is 10 parts by weight, further preferably 20 parts by weight.

Further, the rubber composition of the present invention can contain a silane coupling agent. As the silane coupling agent, any silane coupling agent conventionally used in combination with a silica filler can be suitably used. Bis (3-triethoxysilylpropyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, etc. are particularly preferably used from the viewpoint of both the effect of adding the coupling agent and the cost.

The amount of the silane coupling agent is as follows:
The amount is preferably 1 to 20% by weight based on the amount of the silica. If the amount of the silane coupling agent is less than 1% by weight, the effect of adding the silane coupling agent tends to be insufficient. If the amount is more than 20% by weight, the coupling effect cannot be obtained despite the cost increase, and the reinforcing property is increased. , Abrasion resistance tends to decrease. From the viewpoints of the dispersing effect and the coupling effect, the amount of the silane coupling agent is more preferably 15% by weight at the upper limit and 2% by weight at the lower limit.

The rubber composition of the present invention contains, in addition to the rubber component, carbon black, a polyoxyalkylene glycol compound, silica, and a silane coupling agent,
Used in the usual rubber industry, such as inorganic fillers such as clay, aluminum hydroxide and calcium carbonate, as required, softeners, anti-aging agents, vulcanizing agents, vulcanization accelerators, vulcanization accelerators, etc. A compounding agent can be appropriately compounded.

The rubber composition of the present invention comprises a tire tread,
It can be suitably used for tire members such as carcasses, belts, sidewalls, beads, vibration-proof rubbers, belts, hoses, and other various industrial rubbers.

[0029]

EXAMPLES The present invention will be specifically described below based on examples.
They do not limit the invention.

Hereinafter, the method for producing the polyoxyalkylene glycol compound used in the Examples and Comparative Examples, the description of various other chemicals, and the description of the test methods will be summarized.

<Production of polyoxyalkylene glycol compound> R ¹ , R ² , R ³ shown in Table 1 were prepared by the following method.
And a polyoxyalkylene glycol compound represented by the general formula (1) having n, and a polyoxyalkylene represented by the general formula (2) having R ¹ , R ² , R ³ , R ⁴ and n shown in Table 1. A glycol compound was produced.

(Compound) In 2-butanone, 50 g of polyethylene glycol having a number average molecular weight of 400 and 30 g of phenyl isocyanate were reacted at 60 ° C. for 3 hours to obtain a compound.

(Compound) In 2-butanone, 50 g of polyethylene glycol having a number average molecular weight of 600 and 22.2 g of benzyl isocyanate were reacted at 60 ° C. for 3 hours to obtain a compound.

(Compound) A compound was obtained by reacting 50 g of UNIOX M-400 (manufactured by NOF Corporation) with 32.2 g of benzyl isocyanate in 2-butanone at 60 ° C. for 3 hours. .

[0035]

[Table 1]

<Other Various Chemicals> Diene rubber: SBR15 manufactured by JSR Corporation
02 (styrene - butadiene copolymer) Carbon black: Showa Cabot Co. Ltd. SHOWBLACK ^{_{N220 (N 2 SA: 125m 2}} / g) Antioxidant: Ouchi Shinko Chemical Industrial Co. of Co. Nocrac 6
C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) Stearic acid: Stearic acid manufactured by NOF Corporation Zinc oxide: Zinc flower No. 1 manufactured by Mitsui Kinzoku Mining Co., Ltd. Sulfur: powder sulfur manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator TBBS: Noxeller NS (N-tert-butyl-2-benzothiazylsulfenamide) manufactured by Ouchi Shinko Chemical Co., Ltd. Polyethylene glycol: NOF PEG4 manufactured by
00 (number average molecular weight 400)

<Test Method> (Workability) Measured at 130 ° C. in accordance with the Mooney viscosity measurement method specified in JIS K6300. The Mooney viscosity (ML _{1 + 4} ) of Comparative Example 1 was defined as 100 (reference) and expressed as an index by the following formula (Mooney viscosity index). The larger the index, the lower the Mooney viscosity and the better the processability.

(Mooney viscosity index) = (ML of Comparative Example 1)
_{1 + 4} ) ÷ (ML _{1 + 4 of} each formulation) × 100

(Abrasion Test) Lambourn abrasion tester A Lambourn abrasion test was performed under the measurement conditions of a temperature of 20 ° C., a slip ratio of 20%, and a test time of 5 minutes. The volume loss of each formulation was calculated, and the loss amount of Comparative Example 1 was set to 100 (reference).
The index was expressed by the following formula (wear index). The larger the index, the better the wear resistance.

(Wear index) = (loss of comparative example 1) ÷
(Loss of each formulation) x 100

(Rolling resistance index) Using a viscoelastic spectrometer VES (manufactured by Iwamoto Seisakusho), a temperature of 7
The measurement was performed under the conditions of 0 ° C., an initial strain of 10%, and a dynamic strain of 2%. The tan δ of each formulation was measured, and the tan δ of Comparative Example 1 was measured.
δ was taken as 100 (reference), and expressed as an index (rolling resistance index) by the following formula. The higher the index, the better the rolling resistance characteristics.

(Rolling resistance index) = (tan of Comparative Example 1)
δ) ÷ (tan δ of each formulation) × 100

(Wet skid test) ASTM E3 using a portable skid tester manufactured by Stanley
The wet skid resistance was measured in accordance with the method of Example 03-83, and the wet skid resistance of Comparative Example 1 was set to 100 (reference), and expressed as an index by the following formula (wet skid index). The higher the index, the better the wet skid performance.

(Wet skid index) = (wet skid resistance of each composition) / (wet skid resistance of comparative example 1) × 100

Examples 1 to 4 and Comparative Examples 1 and 2 Kneading and compounding were carried out according to the compounding recipe shown in Table 2 below to obtain various test rubber compositions. Table 3 shows the blending amount of the polyalkylene glycol compound. These compounds were press-vulcanized at 170 ° C. for 20 minutes to obtain vulcanized products, which were tested for the above-mentioned properties. Table 3 shows the results.

[0046]

[Table 2]

[0047]

[Table 3]

As is clear from Table 3, in comparison with Comparative Example 2 in which polyethylene glycol was blended, in Examples 1 to 4 in which a polyalkylene glycol compound having a urethane bond was blended, workability and abrasion resistance were maintained. As a result, the rolling resistance characteristics and the wet grip performance could be improved.

[0049]

According to the rubber composition of the present invention, by blending a polyalkylene glycol compound having a urethane bond, while maintaining processability and abrasion resistance,
Low heat build-up and wet grip performance can be improved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 9/00 C08L 9/00 // (C08L 7/00 71:02 71:02) (C08L 9/00) 71:02) F term (reference) 4J002 AC012 AC021 AC022 AC031 AC061 AC071 AC081 AC091 BB151 BB181 CH023 CH053 DA036 DE147 DE237 DJ017 DJ037 FD017 FD030 FD150 GM00 GM01 GN00 GN01 4J005 AA02 BD05

Claims (1)

[Claims] 1. A carbon black of 5 to 150 parts by weight per 100 parts by weight of natural rubber and / or diene synthetic rubber.
And 0.1 to 25 parts by weight of a polyoxyalkylene glycol compound represented by the following general formula (1) or (2) based on 100 parts by weight of the carbon black.
A rubber composition formulated by weight. Embedded image Wherein R ¹ and R ³ are an alkyl group, a benzyl group or an aryl group, which may be the same or different. R ² is a methylene group, an ethylene group, a propylene group or a tetramethylene group And all may be the same or different. R ⁴ is an alkyl group or an aryl group having 1 to 22 carbon atoms. N is a positive integer of 100 or less.)