Common Problems of PVC Products

1. Yellow Turns Black

Inorganic yellow pigments must not contact organotin, organozinc and similar additives.
Blackening may also occur during vulcanization.

2. White Turns Yellow

Caused by heat-unstable stabilizer, insufficient stabilizer dosage, unstable white pigment, excessive sunlight exposure, oven temperature too high, impure plasticizer, lack of antioxidant or UV absorber.

3. Black Frosting (Blooming)

Improve plasticizer formulation, use cold-resistant additives, apply high-quality stabilizer and premium glossy black pigment.

4. Color Migration

Pigment stability is insufficient or stabilizer dosage is too low.

5. Transparency Becomes Hazy

High humidity environment or moisture absorption.

6. Poor Heat Resistance

Insufficient stabilizer performance or impure plasticizer.

7. Uneven Curing (Top & Bottom)

Check oven heating elements for damage and adjust distance between upper and lower heaters.

8. Product Easily Breaks or Cracks

Under-curing, uneven oven temperature, excessive thickness, impure plasticizer, excessive calcium powder.
Use premium resin and reduce fillers.

9. Oil Bleeding on Surface

Excessive hard oil used (eco-products should use hard powder). Replace plasticizer.

10. Color Fading

Poor pigment stability, additive incompatibility, or impure plasticizer.

11. Black Not Dark Enough

Use high-gloss premium black pigment. Add a small amount of purple and blue pigment if necessary.

12. Strong Odor

Use eco-friendly plasticizer and odorless stabilizer.

13. Environmental Compliance Issues

Adjust material formulations according to customer's environmental standards.

14. Pinholes on Surface

Insufficient vacuum degassing or moisture in resin powder.

15. Sand Holes / Porosity

Material too thick, poor flow, mold too fine/deep, or mold overheated.

16. Poor Adhesion

Likely caused by impure plasticizer, oil bleeding, excessive lubricant in stabilizer, or missing bonding primer.

17. Holes Form During Baking

Raw material is damp or contaminated with water.

18. Flow Marks on Edges

Mold aluminum defects, uneven oven temperature, moisture in material, insufficient vacuum, excessive pigment usage.

19. Local Burning / Scorching

Mold aluminum defects, uneven oven temperature, excessive recycled material.

20. Surface Texture Defects

Insufficient mixing time, insufficient vacuum degassing, or sandblasted mold.

21. Severe Shrinkage

Adjust resin-plasticizer ratio, reduce plasticizer, replace hard oil with hard powder, change plasticizer type.

22. Product Too Soft or Too Hard

Adjust resin-plasticizer ratio (higher resin = harder; higher plasticizer = softer). Use soft oil, hard oil, or hard powder accordingly.

23. Color Too Transparent or Too Dull

Adjust pigment dosage.

24. Yellow / Oxford Color Transparency or Light Transmission Issues

Use non-discoloring pigments (yellow, red, blue are most unstable), high-quality plasticizer, increase stabilizer dosage.

25. Color Change Over Time

Use premium plasticizer, pigment, and stabilizer.

26. Transparent Material Too Thick at Same Ratio

Replace plasticizer, use high-flow resin, consider ambient temperature (low temperature thickens material), use flow-enhancing stabilizer.

27. Transparent Material Too Thin & Cannot Adhere to Mold Walls

Increase resin content or add thickening powder.

28. Transparency Not Sufficient

Use ultra-clear resin, ultra-clear stabilizer, and avoid hard powder.

29. Sedimentation / Layer Separation / Surface Skinning

Replace with high-quality resin, change stabilizer, excessive pigment dosage.

30. Heavy Smoke or Fire Risk During Baking

Replace plasticizer and hard oil, lower oven temperature.

31. Poor Flow in Cold Weather

Use high-flow plasticizer and resin, replace stabilizer, excessive pigment usage.

32. Transparent Product Turns Yellow

Replace plasticizer and stabilizer.

33. White Cannot Reach Grade 4

Replace plasticizer, use premium stabilizer and pigment.