1、 Three major factors affecting CPE performance
Firstly, it is the type of CPE used. CPE obtained from high molecular weight polyethylene has high viscosity and tensile strength, but the adhesion between this CPE and PVC resin is low. CPE obtained from low molecular weight polyethylene has low viscosity and tensile strength, and CPE obtained from high-density polyethylene has good heat resistance.
Secondly, it is the size of the raw material particles. When the particle size is too small, it is easy to form jelly or clumpy CPE, and when the particle size is too large, the distribution of chlorine is uneven.
Once again, it is the level of CPE chlorination. When the chlorine content is below 25%, it has poor compatibility with PVC and cannot be used as a modifier; When the chlorine content is greater than 40%, it has good compatibility with PVC and can be used as a solid plasticizer, not suitable as an impact modifier; CPE with a chlorine content of 36-38% has good elasticity and compatibility with PVC, making it widely used as an impact modifier for PVC. Currently, CPE with a chlorine content of 35% is commonly used. CPE with a chlorine content of around 35% has low crystallinity and glass transition temperature, good rubber elasticity, and suitable compatibility with PVC. It is widely used as an impact modifier for PVC hard products.
2、 The Effect of CPE Addition on PVC
When the addition amount is below 10 minutes, the impact strength of PVC increases rapidly with the addition of CPE, but further increasing the addition amount of CPE results in little improvement in the impact strength of PVC. Therefore, as an impact resistant agent, the appropriate amount of CPE to be added is 8-10 parts. As CPE increases, the tensile strength of PVC blends continues to decrease, while the elongation at break increases. If the toughness is expressed as the product of tensile strength and elongation at break, it is obvious that the toughness of PVC will significantly increase with the increase of CPE addition.
Post time: Aug-01-2023
