KR20010081693A - Rubber composition with high hardness - Google Patents

Abstract

PURPOSE: A rubber composition is provided, which is improved in hardness, carbon dispersibility, reinforcement, modulus, tensile strength and elongation at fracture. CONSTITUTION: The rubber composition comprises 100 parts by weight of rubber; 5-30 parts by weight of a reinforcing resin; and 0.1-2 parts by weight of a silane coupling agent. Preferably the reinforcing resin is preferably a straight phenol formaldehyde resin or a cashew nut oil modified resin; and the silane coupling agent is Si-69, X-50S, (RO)3-Si-(CH2)n-SH, (RO)3-Si-(CH2)3-SCN, (RO)3-Si-(CH2)3-Cl or (RO)3-Si-CH=CH2.

Description

High Hardness Rubber Composition {RUBBER COMPOSITION WITH HIGH HARDNESS}

The present invention relates to a high hardness rubber composition, and to a high hardness rubber composition in which carbon dispersibility and reinforcement are improved by applying a silane coupling agent in order to overcome the limitation of hardness improvement by addition of a reinforcing resin.

In rubber compositions, a large amount of reinforcing fillers such as carbon black, silica, etc. are used for high hardness / stiffness, and in the case of using such a large amount of fillers, due to the high viscosity, This is a very bad problem. To improve this, a method of using phenol formaldehyde novolak reinforing resin and methylene donor in place of some of the reinforcing fillers can be used to easily improve fairness under hardness retention and hardness increase. Known.

The improvement in processability can be achieved by having plasticity at the processing temperature of the composition since the phenolic resin is thermoplastic. The phenolic resin / methylene donor system is permanently crosslinked upon vulcanization of the rubber composition and thus remains reinforcement even at elevated temperatures.

As such, the addition of methylene donor and reinforcing resin in rubber formulations is characterized by the hardness, stiffness, tear resistance, abrasion resistance, tensile strength, modulus ( modulus) Phenolic reinforcement resins include styrene-butadiene rubber (SBR), butadiene rubber (BR), ethylene-propylene diene rubber (EPDM), chloroprene rubber (CR), It is compatible with halobutyl rubber and natural rubber (NR) and can be applied up to 30phr.

However, there are limitations in improving hardness with reinforcing resins. Especially in the case of APEX or racing tires that require high hardness, it is impossible to improve the hardness only with reinforcement resin.

The same is true for farm tires. As it is used under rough dirt road conditions, it must have sufficient resistance to pass through stumps such as rocks and trees around farms. In order to increase the hardness, stiffness and tear resistance of such farm tire tread compositions, it is necessary to improve the penetration resistance and the overall performance of the tire. The hardness or rigidity of the composition can be improved by increasing the reinforcing filler, such as carbon black or silica. However, the increased amount of fillers leads to undesirable phenomena that increase the viscosity of the green composition and lower the processability.

It is an object of the present invention to improve the above problems by improving the interaction between rubber and carbon black, and at the same time to improve the compatibility of the reinforcement resin and rubber to provide a high hardness rubber composition.

The high hardness rubber composition of this invention contains 5-30 weight part of reinforcement resin, and 0.1-2 weight part of silane coupling agents to 100 weight part of general-purpose rubber | gum.

The present invention has a limitation in improving the hardness by the addition of a reinforcing resin, and thus overcomes the limitation by using a silane coupling agent.

In the rubber composition of the present invention, as the reinforcing resin, a straight phenol formaldehyde resin, cashew nut oil modified resin can be used, and in view of the effects of the present invention, It is preferable to mix | blend 5-30 weight part with respect to 100 weight part of raw material rubbers. That is, less than 5 parts by weight of the effect is insufficient, and over 30 parts by weight is not preferable because only the cost increases without increasing the effect.

The silane coupling agent used in the present invention is generally sulfur-based Si-69 (from Degussa, (CH ₃ CH ₂ O) ₃ -Si- (CH ₂ ) ₃ -S _4- (CH ₂ ) ₃ -Si- (OCH ₂ CH ₃ ) ₃ ) and X-50S (Degussa, compound mixed with 50% N330 (carbon black) + 50% Si-69) are preferably used, and other silane coupling agents of Table 1 may be used. It may be. The content ratio is added in the rubber compounding 0.1 to 2 parts by weight with respect to 100 parts by weight of rubber in consideration of the effects of the present invention. If it is less than 0.1 part by weight, the effect is insufficient, and if it is more than 2 parts by weight, there is no synergy.

Table 1

constitutional formula product name Vulcanization system (CH ₃ CH ₂ O) ₃ -Si- (CH ₂ ) ₃ -S _4- (CH ₂ ) ₃ -Si- (OCH ₂ CH ₃ ) ₃ TESPT Sulfur vulcanization (RO) ₃ -Si- (CH ₂ ) _n -SH MERCAPTO SILANE Sulfur vulcanization (RO) ₃ -Si- (CH ₂ ) ₃ -SCN TCPTS Sulfur vulcanization (RO) ₃ -Si- (CH ₂ ) ₃ -Cl CIPTES Thiourea / metal oxide (RO) ₃ -Si-CH = CH ₂ VINYL SILANE Peroxide

To the rubber composition of the present invention, conventional rubber composition additives such as fillers, vulcanization accelerators, process oils and the like can be added in a usual amount of use.

Although this invention is demonstrated in detail, this invention is not restrict | limited by these.

Examples and Comparative Examples

According to the composition of Table 2, each component was combined in an open mill to prepare a rubber composition, and then a specimen was prepared to measure physical properties such as hardness and tensile strength. Physical property measurement results are also shown in Table 2.

TABLE 2

Example 1 Example 2 Example 3 Example 4 Natural rubber (phr) Carbon black (phr) Reinforcement resin (phr) Adhesive (phr) (* 3) Si-69 (phr) Cyrez 964 (HMMM, phr) (* 4) 1006515 (* 1) 4-3.6 1006515 (* 1) 40.13.6 1006515 (* 2) 40.13.6 1006515 (* 2) 423.6 Hardness (JIS) 300% Modulus (kgf / ㎠) Tensile Strength (kgf / ㎠) Elongation at Break (%) 90/93136 / -136 / 77297/85 92/94146 / -172 / 123371/145 93/94137 / -172 / 117381/137 93/94146 / -185 / 123391/154

* 1: linear phenol formaldehyde resin ( ),

* 2: CNSL modified resin ( ),

* 3: adhesive: para-octyl phenol formaldehyde resin,

* 4: hexamethoxymethyl melamine

As can be seen from Table 2, the rubber compositions prepared by the present invention have a very high hardness, excellent modulus, tensile strength and elongation at break.

As can be seen from the above, the rubber composition produced according to the present invention has improved interaction between rubber and carbon black, and at the same time improved compatibility between reinforcing resin and rubber, and apex and race requiring high hardness. Reinforcement resins, including tires, OTR tread compositions, are applicable to all rubber compositions to which they are applied.

Claims (3)

The high hardness rubber composition containing 5-30 weight part of reinforcement resins, and 0.1-2 weight part of silane coupling agents with respect to 100 weight part of raw material rubbers. 2. The high hardness rubber composition according to claim 1, wherein the reinforcing resin is a straight phenol formaldehyde resin or cashew nut oil modified resin. The silane coupling agent of claim 1, wherein the silane coupling agent is Si-69, X-50S, (RO) ₃ -Si- (CH ₂ ) _n -SH, (RO) ₃ -Si- (CH ₂ ) ₃ -SCN, (RO ) ₃ -Si- (CH ₂ ) ₃ -Cl or (RO) ₃ -Si-CH = CH _{2 It} is a high hardness rubber composition.