How to improve the processing performance of low-hardness silicone rubber?

Wed Aug 31 11:05:49 CST 2022

1. The effect of toughening agent on the transparency of silicone rubber

Since there are no fillers in MQ raw rubber, its appearance is glassy and transparent. According to the experimental results, the toughening agent of 0.3 phr has almost no effect on the transparency of silica gel, and the sample still maintains a high degree of transparency. When the addition amount is increased to 1 part, the transparency decreases.

2. The effect of toughening agent on the Mooney viscosity of MQ raw rubber

Through the change of the Mooney viscosity of the rubber, it can be seen that after adding the toughening agent, the viscosity of the rubber increases and the intermolecular force increases, which improves the processability of the silica gel.

Compared with GS-100, GS-101 improves Mooney viscosity more efficiently.

silicone rubber

3. Evaluation of toughening agent on the processability of MQ raw rubber

MQ raw rubber without toughening agent is difficult to mix on the open mill, the rubber is easy to break, and it is not easy to roll off;

After adding 0.3phr toughening agent, the green strength of the MQ raw rubber is improved, the rubber bag roller is normal and the thin pass operation can be carried out;

After adding 1.0phr toughening agent, the green strength of the rubber compound is obviously improved, even better than the processing performance of high-hardness silicone rubber. Not only can normal rubber mixing be carried out, but also a large amount of filler can be filled.

4. Recommendations for the use of tougheners in low-hardness silica gel

Since the intermolecular shear is small and the temperature rise is small during the mixing of low-hardness silica gel, it is recommended that the mixing temperature be controlled between 40 degrees and 50 degrees, that is, to increase the dispersion of the toughening agent in the silica gel, improve the toughening effect, and also Conducive to shortening the mixing time.

The toughening agent of 0.3phr can significantly improve the processability of low-hardness silica gel, making it easy for the rubber compound to be rolled and mixed.

For applications with high transparency requirements, it is recommended to control the amount of toughening agent added, with 0.3phr being the best.

For products that need to add a large amount of functional fillers, such as products with high electrical conductivity and high thermal conductivity, it is advisable to increase the amount of toughening agent added to facilitate higher filling.

Compared with GS-101, GS-101 has a higher efficiency in improving the strength of raw rubber, while GS-100 has a smaller effect on Mooney viscosity. It is suitable for formulas with high Mooney viscosity and difficult extrusion.

silicone rubber