In today's material field, PVC foam boards are highly valued for their unique properties. However, with the continuous expansion of their application range, related issues are becoming increasingly prominent. In the production process, how to achieve uniform foaming and control the pore structure to ensure their physical properties and stability is a challenge.
1.The problem of yellowing on the surface of PVC foam boards
Cause analysis: The extrusion temperature is too high, the stability of the stabilizer is insufficient, the initial coloring is poor, or over-plization causes.
Solution: Reduce the processing temperature. If it doesn't improve, adjust the formulation by selecting stabilizers with good initial color and thermal stability, and the lubrication system by choosing efficient lubricants to ensure proper plasticization. You can choose our company's calcium zinc stabilizer SZ915, along with lubricants G60, PE wax, OPE wax, etc.
2.The problem of yellowing in the core layer of PVC foam board.
Cause analysis: High temperature of the cylinder and mold, improper selection ofants, excessive thickness of the board, slow heat dissipation in the core layer, and the stability of the stabilizer are related.
Solution: Appropriately reduce the mold temperature, select an efficient lubricant and adjust the lubrication combination, reduce the amount of yellow hair and increase amount of white hair in thick plates, and choose a stabilizer with better thermal stability.
3.Bending problem of PVC foam board surface.
Cause analysis: Uneven material flow or insufficient cooling. The factors causing uneven material flow generally include large fluctuations in traction or imbalance between internal and externalation in the formula.
Solution: Check if the cooling water passage is unobstructed to ensure uniform and adequate cooling of the plate surface; inspect the traction machine to stable traction speed; adjust the amount of lubricant to achieve lubrication balance and stabilize the current.
4.The cross section of the PVC foam board shows bubbles or foam delamination.
Cause analysis: It can be attributed to one point, which is the insufficient melt strength. This is mainly due to the excessive foaming agent or foaming regulator, leading to an imbalance in their ratio, or the quality issue of the foaming regulator; poor plasticization, low processing temperature or excessive lubric.
Solution: Adjust the dosage of foaming regulator and foaming agent, choose foaming agents with higher melt strength and viscosity; appropriately reduce the dosage external lubricant PE wax, and appropriately increase the temperature of the screw barrel to improve plasticization. The high-viscosity foaming regulator S902 from company can be chosen.
5.The problem of uneven thickness of PVC foam board surface.
Cause analysis: Uneven discharge.
Solution: The mold lip opening can be adjusted. If the flow rate is too high, the flow restrictor can be adjusted. The formula can be adjusted. Usually, increasing the internal lubricant makes the middle thicker, while increasing the external lubricant speeds up the flow on both sides. Adjust the usage internal and external lubricants according to the actual situation. Our company's internal lubricant G60 and external lubricant PE wax can be chosen.
