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How to solve the problem of low gloss on the surface of injection molded plastic?

Update:30-01-2021
Summary:

The production of plastics needs to consume petroleum r […]

The production of plastics needs to consume petroleum resources, and petroleum resources are non-renewable resources. Everyone is responsible for producing high-quality plastic products with limited resources. Sometimes, the surface of the plastic injection molded is dull, or has uneven gloss and color. Why? For this phenomenon, the reasons and solutions are summarized.

1. The injection speed of the injection molding machine is too fast, and the material retention time is too long, which will also cause the surface gloss of the Meltblown cloth mould product to decrease; solution: reduce the injection speed of the injection molding machine to reduce the retention time of the material.

2. The material has poor thermal stability. Generally speaking, it is easy to decompose under 100℃ environmental conditions, and the decomposition will accelerate at 180℃. Solution: Use materials with good thermal stability and gloss, or you can add a reasonable amount of thermal stabilizer to the materials.

3. During the processing, the mold temperature is too low and the cooling rate is too fast. When the melt is still filling the mold, a hard shell has been formed on the cavity wall. The hard shell is susceptible to various forces and changes. White becomes muddy, reducing the surface gloss of the product. Solution: Before starting to use the mold, the mold should be heated in advance to increase the working temperature of the mold, reduce the cooling rate or adopt local heating at the mold gate.

4. The moisture absorption or volatile content of raw materials is a common cause of poor surface gloss of plastic products. Solution: Dry the material fully before use and add a dryer if necessary.

5. Excessive use of release agent will also cause such defects on the surface of plastic products. Solution: Try not to use or use a small amount of release agent, and apply it evenly.

6. The quality of product raw materials has a greater impact on the surface gloss of plastic products, and only mixed with impurities will reduce the surface gloss of the product. Solution: Use high-quality raw materials or remove impurities before use.

7. If the size of the runner and gate of the injection molding machine is too small, the poor exhaust will also cause the product to have poor surface gloss. Solution: The size of the runner and gate should be increased, and an exhaust groove should be added.

In addition to the above methods, there are also common methods such as adding brightness enhancement method, blending brightness enhancement method, morphology control brightness enhancement method, molding equipment smoothness control, secondary processing brightness enhancement method and surface coating brightness enhancement method. The method can improve the surface gloss of plastic products.

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