How can we improve the heat resistance of PVC plastics?
After PVC plastic products are processed into finished products, many manufacturers or merchants will reflect that PVC plastics have poor heat resistance. So how do you improve the heat resistance of PVC plastics?
1, PVC copolymer
When the composition of the VC (vinyl chloride) and the other monomer copolymer resin contains a polar or large group component, the heat distortion temperature of the copolymer is correspondingly increased, and the heat resistance is better than that of the PVC to obtain a heat resistant product. The softening temperature of PVC is 78 ° C, and the softening temperatures of the copolymers of vinyl chloride-vinyl chloride, methyl chloride-methyl methacrylate, and vinyl chloride-acrylonitrile are 100-130, 85, and 140-150 °C, respectively.
2, PVC chlorination
It is obtained by chlorination of PVC resin. Its chlorine content is 62%~68%. Chlorinated polyvinyl chloride can be used continuously at 100 ° C (20 ~ 35 ° C higher than PVC), the maximum operating temperature can reach 100-105 ° C, and chemical stability, flame retardancy, cold resistance are better than PVC. However, the anti-corrosion requirements of chlorination equipment are strict, the resin is not easy to process, and the impact toughness is poor, which restricts its application and development.
3, PVC cross-linking
Crosslinked PVC can be obtained by radiation crosslinking method and chemical crosslinking method. The crosslinked PVC products have higher mechanical strength, good dimensional stability, heat deformation resistance, wear resistance and chemical resistance than ordinary PVC products. The radiation crosslinked wires can be continuously used at 100~110 °C.
4, PVC blended with other polymers
The PVC is mixed with other polymers in a certain ratio, and the properties of the blend (fully compatible) are improved compared to PVC. Because the compatible two polymers can be mixed to achieve molecular-level intermixing, a single-phase structure is formed, so that the properties of the blend are supplemented and strengthened, such as PVC/PS, PVC/PE, PVC/CPVC, and the like.
5, adding heat-resistant modifier
The heat-resistant modifier is a type of polymer which has been developed and produced to improve the heat resistance of PVC. (1) Polyglutarimide: prepared by reacting polymethyl methacrylate with CH3NH4: (2) SMA (styrene-maleic anhydride copolymer) is a better PVC heat-resistant modification introduced by American manufacturers. Agent: (3) HT-510 (Japan) is a series of acryl-based imine-based copolymers, which is a practical heat-resistant refractory agent for effectively improving the transparent and opaque PVC mixture.
6, adding inorganic value materials in PVC
After adding a certain amount of filler, it can improve the heat resistance of PVC. Commonly used fillers are: heavy calcium carbonate, light calcium carbonate, precipitated calcium carbonate, calcined pottery, barium sulfate, red mud, titanium from powder and so on.
7. Add fiberglass to PVC
Adding 20%~30% glass fiber to PVC, its heat resistance can be increased to above 100 °C. It is a good adhesion of PVC resin to glass fiber without adding (or adding less) plasticizer. Especially for long fiber reinforced PVC, the heat distortion temperature increase is more obvious.
8, ordinary CPVC improve Vicat
Material processing properties will deteriorate and need to be added to the impact modifier to offset. The use of α-methyl styrene to increase Vicat (about 1% of its vitamins increased by 2-3 ° C), the processing temperature will be improved, physical and mechanical properties will also be reduced, but the amplitude is smaller than CPVC, while Also add impact modifiers to offset.
9. Some varieties of PVC heat-resistant modifiers:
Japan's Zhongyuan TELALLOY A15 is an ABS-based heat-resistant modifier for PVC, which can greatly improve the heat resistance of PVC resin. The use of this product in soft and semi-rigid artificial leather can greatly improve its wrinkle resistance.