Why Do Injection Molded Products Fade?
Color fading in injection molded products is a complex issue, often resulting from a combination of factors.
1. Raw Material and Pigment Quality
1.1 Poor Lightfastness of Pigments/Dyes
Cause: Pigments or dyes with insufficient lightfastness degrade under prolonged ultraviolet (UV) exposure, leading to gradual color fading or changes.
Solution: Use pigments with high lightfastness and heat resistance. Incorporate UV absorbers or antioxidants to enhance color stability.
1.2 Improper Material Formulation
Cause: Inadequate pigment dosage or uneven dispersion during material mixing can result in color inconsistency or localized pigment concentration issues during molding, reducing colorfastness.
Solution: Strictly adhere to formulation ratios, and use dispersants or additives to ensure uniform pigment distribution.
2. Mold and Post-Processing Effects
2.1 Mold Surface Condition
Cause: Worn or aged mold surfaces can cause friction or chemical reactions during molding, compromising color stability.
Solution: Regularly maintain molds, repair surface damage, and apply protective coatings as needed.
2.2 Post-Processing Techniques
Cause: Improper post-processing steps (e.g., cooling, deburring, surface coating) may trigger localized pigment degradation or oxidation.
Solution: Optimize post-processing methods based on material properties, and control environmental factors like temperature and humidity.
3. External Environmental Factors
3.1 UV Exposure
Cause: Prolonged UV exposure in outdoor or high-light environments induces photochemical reactions in polymers and pigments, breaking down molecular structures and causing fading.
Solution: Add UV-resistant additives to the material or apply protective coatings (e.g., UV-resistant paint) to shield products from direct sunlight.
3.2 Oxidation and Chemical Reactions
Cause: Exposure to high temperatures, humidity, or corrosive environments post-production can trigger oxidation or chemical reactions in polymers/pigments, altering color.
Solution: Store and use products in controlled environments; select materials with strong antioxidant properties.
