What about TPE with no luster?​

What about TPE with no luster?

Injection molded products such as TPR / TPE are prone to dull surface, or uneven luster and color.

For this phenomenon, this paper summarizes nine reasons and solutions.
1. If the injection speed is too fast and the retention time of the material is too long, the surface gloss of the product will be reduced
Solution to the problem: the injection speed and retention time should be reduced.
2. Poor thermal stability of materials, thermal decomposition
Solution to the problem: materials with good thermal stability and glossiness shall be selected or heat stabilizer shall be added to the materials.
3. Low barrel temperature and low nozzle temperature will also reduce the glossiness of the product surface
Solution: the temperature of nozzle and melt should be increased.
4. The mold temperature is too low and the cooling speed is too fast. When the melt is still filling the mold, a hard shell is formed on the cavity wall. The shell is affected by various forces, making it white and muddy, and reducing the glossiness of the product surface
Solution to the problem: the surface temperature of the die should be increased, the cooling speed should be reduced or the local heating should be used at the gate of the die.
5. The surface finish of the mould is poor, which makes the surface of the product dull
Carbon tool steel should be selected as the solution to the problem, and the surface of the mould should be polished carefully to improve the surface finish of the mould.
6. Too much dosage of demoulding will cause such defects on the surface of products
Solution to the problem: try not to use or use a small amount of release agent, and apply evenly.
7. If the back pressure is too small during plasticization, the materials will be plasticized unevenly, and the mixture of materials and colorants will lead to uneven surface color of products,
Solution: back pressure should be increased appropriately.
8. Impurities mixed in the material and non drying will also reduce the glossiness of the product surface
Solution to the problem: the idea should be to remove impurities, fully dry materials, if necessary, add hopper dryer.
9. If the runner and gate are too small and the exhaust is not good, the surface gloss of the product will be poor
Solution to the problem: the runner and gate size should be increased, and the exhaust slot should be added.