Rubber Chem Encyclopedia

The effect of softening system on the physical properties of reclaimed rubber vulcanizates

Create Date:2020-08-11 08:48:30Click volume:4099

The reclaimed rubber softening and plasticizing system composed of softeners or plasticizers can increase the fluidity, plasticity, and adhesion of the rubber during the production process of reclaimed rubber products, and promote the uniform dispersion of powdery compounding agents, which is the subsequent compression and molding process Provide better operating conditions. In actual production, the softening and plasticizing system will not only affect the production process of reclaimed rubber products, but also affect the physical indicators of reclaimed rubber vulcanizates, which are specifically manifested in the following aspects.

1. The softening system affects the tensile strength of reclaimed rubber vulcanizates

When using reclaimed rubber to produce rubber products, the tensile strength of the reclaimed rubber vulcanizate will first increase and then decrease sharply. This is because the addition of softeners will promote the uniform dispersion of carbon black and other compounding agents in the rubber compound, and the tensile strength of the reclaimed rubber vulcanizate will increase. For example, adding less than 10 parts of DBP to nitrile reclaimed rubber products reinforced with carbon black will increase the tensile strength of the reclaimed rubber vulcanizate; if you continue to increase the amount of softening plasticizer, the tensile strength of the reclaimed rubber vulcanizate will drop sharply .

In actual production, the overall appearance of the softening system 2LLYY811 will cause the tensile strength of the reclaimed rubber vulcanizate to decrease. In order to ensure that the tensile strength of the reclaimed rubber vulcanizate meets the requirements of the product, it is better to use high-viscosity rubber oil, coumarone resin or polymer oligomer softener.

2. The softening system affects the tear strength of reclaimed rubber vulcanizates

Tear strength is an important physical performance index of reclaimed rubber. The addition of softening plasticizers usually reduces the tear strength of reclaimed rubber vulcanizates. Different types of reclaimed rubber need to use different softening plasticizers to ensure the tear strength of reclaimed rubber vulcanizates. For example, when petroleum-based softeners are used in the production of nitrile reclaimed rubber products, it is best to use high-aromatic oils with an aromatic content higher than 50%-60%, and try to avoid using paraffin naphthenic oils.

3. The softening system affects the elasticity of reclaimed rubber vulcanizates

The lower the compatibility between the softening system compounding agent and the reclaimed rubber, the worse the elasticity of the reclaimed rubber vulcanizate. Under normal circumstances, the increase in the amount of softener and plasticizer will reduce the elasticity of the reclaimed rubber vulcanizate. Therefore, it is necessary to avoid or reduce the amount of softener in the formulation of highly elastic reclaimed rubber products. In actual production, latex reclaimed rubber using paraffin oil and butyl reclaimed rubber vulcanizate have better elasticity, while reclaimed rubber vulcanizate added with aromatic oil has relatively poor elasticity.

The softening system will also affect the abrasion resistance and fatigue resistance of the reclaimed rubber vulcanizate, so I won't go into details here.

The same softening plasticizer has different effects on the tensile strength, tear strength, elasticity and other physical properties of different types of reclaimed rubber vulcanizates. Rubber product manufacturers need to determine the comprehensive physical properties of the product. For example, from the perspective of tensile strength, butyl reclaimed rubber and EPDM reclaimed rubber generally use low unsaturation paraffin oil or naphthenic oil, and nitrile reclaimed rubber can use aromatic oil or ester softener. Later editors will continue to discuss with you the specific influence of the softening system on the physical indicators of the reclaimed rubber vulcanizate.

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