The effect of CPE dosage added in PVC

CPE models are generally identified by, for example, chlorincated polyethylene 135A, 135B, 140B, CPE135C, etc., where the first digits 1 and 2 represent the residual crystallinity (TAC value), 1 represents the TAC value between 0-10%, and 2 represents the TAC Value> 10%, the second and third digits indicate the chlorine content, such as 35 for the chlorine content of 35%, and the last digit is the letter ABC, which is used to indicate the molecular weight of the raw material PE, where A is the largest and C is the smallest.

The influence of molecular weight: APE of CPE has the largest molecular weight and large melt viscosity. Its viscosity is the best match with PVC. It has the best dispersion effect in PVC and can form an ideal network-like dispersion. Therefore, A of CPE is generally selected. The molding material is used as a modifier of PVC.

TAC value: The TAC value indicates the content of PE crystals and amorphous form in the CPE molecule, and to some extent reflects the uniform distribution of chlorine atoms on the CPE molecule. A large TAC value indicates that the PE segment has more crystals, and the PE chain The segment has poor compatibility with PVC. A small TAC value results in good compatibility between PE and PVC. Generally, a CPE with a TAC value less than 5 is selected as the impact agent.

When the amount of addition is less than 10 minutes, the impact strength of PVC increases quickly with the addition of CPE, but further increase of the amount of CPE increases the impact strength of PVC little. Therefore, as an anti-impact agent, the amount of CPE added is preferably 8-10 parts. At the same time, as the CPE increases, the tensile strength of the PVC blend continues to decrease and the elongation at break increases. The product of the elongation at break indicates its toughness, and it is clear that the toughness of PVC will obviously increase with the increase in the amount of CPE added.