Due to poor distribution of pigments or fillers, the color of plastic or pigment discoloration on the surface of plastic parts is uneven. The reasons for uneven color vary depending on the phenomenon presented. The uneven distribution of pigments near the feeding port is mainly caused by poor thermal stability of the plastic when the color of the entire plastic part is uneven, and the uneven color of the fusion joint is related to the properties of the pigments.
The area indicated by the arrow indicates uneven gloss of the plastic mold
Uneven gloss of plastic mold products:
1. The cooling rate and properties of the rubber material result in different glosses;
2. Uneven gloss may occur in areas where the mold temperature is too low;
3. The temperature of the rubber material is too low;
4. Using excessive release agents;
5. Poor surface polishing of the mold;
Analysis of the reasons for uneven gloss of plastic parts:
1. Aluminum foil or thin sheet pigments have luster along the direction of the material flow, and the pigments have no directional distribution and uneven color at the feeding port, fusion joint area, and multiple feeding ports;
2. Poor pigment quality;
3. When rolling and stirring, the pigment only adheres to the surface of the material particles;
4. Plunger injection molding machines are prone to uneven color;
5. Uneven plasticization;
6. Uneven distribution of fiber fillers, accumulation and exposure, or resin dissolution when plastic parts come into contact with solvents, resulting in exposed fibers;
7. Decomposition of plastics or pigments;
8. There is moisture, oil stains, or excessive release agent on the surface of the mold;
9. Mixing different materials into plastics and pigments;
10. Low crystallinity or uneven wall thickness of plastic parts, affecting transparency and causing uneven color;