Tips to achieve the optimal pearl effect: 

• Plastic resin must be transparent or semi-transparent. High gloss plastic resin shows pearlescent effect the best.

• Use pigments with good transparency to mix with pearl pigments

• Try not or reduce damage to pearlescent pigments during processing

• Pearlescent pigments need to be fully dispersed and pearlescent pigment flakes need to be parallel to the plastic surface to obtain the optimal pearl effect

• The plastic characteristics and manufacturing process will affect the final products chroma/luster. The normal pearlescent pigments dosage in plastic is 0.5-2%. For thin film or thin plastic products, the dosage should increases to 4-5%.

• The best way to colour plastic resin is using master batch. Master batch can be made either from coarse or fine resin powder. Polymers with high melt flow index, strong fluidity and molecular weight lower than the resin are recommended, as the addition of pearl pigments will decrease its melt flow index.

Tips to use Special effect mater batch: 

• Avoid long time and sharp stirring to protect pearl platelets crystal structure and ensure the final pearl effect.

• Increase the pressure to improve mixing efficiency and ensure pearl pigments are fully dispersed.

• Increase the temperature in the allowable range and reduce the melt viscosity to minimize the damage to pearl pigments.

• The Mould finish gloss, mould design and manufacturing process could affect the pearlescent pigment flake distribution which will affect the final pearl effect.

Cautions for thermoplastic application:

• Poly Carbonate (PC): before shaping the plastic products, PC needs to have the phenolic antioxidant stabilizing treatment. After process, the antioxidant phenolic group can react with TiO2, and become yellow. So when use normally pearlescent pigments, plastic products will turn yellowish. In this case, should use Pritty Yellow Resistance series (such as 100YR) which are developed to avoid the yellowing phenomenon when apply pearlescent pigments in PC plastic.
• PVC: Pritty pearlescent pigments are suitable for both soft and hard PVC, need to make sure PVC is still transparent after colouring and stabilizing treatment.
• Iron ion will decrease stability of PVC, thus when Gold and Iron pearlescent pigments are used with PVC, a lab test is required.
• Dry before use: in general, all pearlescent pigments contain 0.5% moisture. While almost all plastic resins are hygroscopic, so pearlescent pigments must be dried first before use. When produce hygroscopic master batch, drying the raw materials and final master batch is extremely important.