Reasons for rubber ageing:

1. The color difference is caused by the inconsistency of material proportions and weights.

2. The local color of the product is different after vulcanization by mixing and non-uniform moulding.

3. Excessive curing temperature and long time cause discoloration.

4. Colour powder is not resistant to high temperature and discoloration after vulcanization.

5. The temperature of the hot plate of the vulcanizing machine is different, and the color of different parts of the same product is different.

Improvement measures:

1. Weigh the formula strictly according to the standard.

2. Mixing according to the standard of mixing process.

3. Control the curing temperature and time, according to the process standard.

4. Adjust the formula and use high temperature resistant color powder.

5. Maintain the machine and adjust the hot plate temperature.