The principle of action of PVC foaming regulator is mainly achieved by regulating the physical and chemical properties of PVC melt. The specific functions are as follows:
1. Promote plasticization and melting uniformity
The long molecular chain of foaming regulator (ACR) speeds up the plasticization of materials by winding the PVC molecular chain, reduces the processing temperature, and forms a gel network structure. This process not only accelerates the melting speed, but also promotes the uniform dispersion of additives and foaming agents, reducing internal defects in the melt.
2. Enhance the strength and elasticity of the melt
The three-dimensional network structure formed by the entanglement of molecular chains significantly improves the strength of the melt, enabling it to effectively encapsulate gas and resist cell coalescence during the foaming process. At the same time, it endows the melt with elasticity, allowing the pores to expand and shrink uniformly, maintaining a closed cell structure.
3. Regulating the viscoelasticity balance of the melt
The regulator adjusts the viscoelasticity of PVC melt, prolongs the foaming time window, and matches the decomposition rate of the foaming agent with the gas diffusion rate. This regulation can reduce the rate of bubble rupture (as shown in experimental data, the rupture rate has decreased from 25% to 8%) and optimize the uniformity of gas distribution in the melt.
4. Optimize the pore structure and stability
The improved melt strength and elasticity can suppress the extrusion rupture of adjacent pores, forming a small and uniform closed cell structure. Regulators with higher molecular weight, such as HL530, can further reduce the density of the product, while regulating the fluidity of the molecular chain to prevent collapse of the pores caused by excessive relaxation.
5. Improve the surface and mechanical properties of the product
The improvement of melt homogeneity reduces surface flow marks and shrinkage defects, and enhances surface cleanliness. The increase in melt strength indirectly enhances the impact resistance and dimensional stability of the product.
In summary, its principle of action is essentially to achieve precise control of melt strength, viscoelasticity, and foaming kinetics through physical winding and chemical synergistic effects, thereby balancing cell density, structural integrity, and processing efficiency.
Post time: May-15-2025
