1, PVC copolymer
If the composition of the copolymer resin of PVC and other monomers contains polar or large group components, the heat distortion temperature of the copolymer increases correspondingly, and the heat resistance is better than that of PVC, and the heat-resistant product is obtained. The softening temperature of the PVC is 78 ° C, and the copolymer vinyl chloride - vinylidene chloride, vinyl chloride - methyl methacrylate, vinyl chloride - acrylonitrile softening temperature of 100 ~ 130, 85, 140 ~ 150 ° C.
2, PVC chlorination
Chlorinated polyvinyl chloride is obtained by chlorination of PVC resin, and its chlorine content is 62%~68%. Chlorinated polyvinyl chloride can be continuously used at 100 °C (20~35 °C higher than PVC), the highest The use temperature can reach 100~105°C. The chemical stability, flame retardancy and cold resistance are better than PVC. However, the anti-corrosion requirements of chlorination equipment are strict. The resin is difficult to process, and the impact toughness is poor, which restricts its application and development. .
3, PVC cross-linking
Cross-linked PVC can be obtained by radiation cross-linking method and chemical cross-linking method. The cross-linked PVC products have higher mechanical strength, good dimensional stability, heat-resistant deformation, wear resistance and chemical resistance than ordinary PVC products. Radiation cross-linked wires can be used continuously at 100~110 °C.
4, PVC blended with other polymers
PVC and other polymers are mixed in a certain ratio, the performance of the blend (fully compatible) is improved compared with PVC. Because the compatibility of the two polymers is mixed, molecular-level intermixing can be achieved, forming a single Phase structure, so that the performance of the blend is supplemented and strengthened, such as PVC / PS, PVC / PE, PVC / CPVC.
5, adding heat-resistant modifier
Heat-resistant modifiers are a class of polymers with high heat resistance developed to improve the heat resistance of PVC.
Polyglutarimide: prepared by the reaction of polymethyl methacrylate with CH3NH4.
SMA (styrene-maleic anhydride copolymer) is a better PVC heat-resistant modifier introduced by American manufacturers.
HT-510 (Japan) is an acrylic series of imine copolymers.
S700N is an α-methylstyrene-acrylonitrile copolymer.
ABS type heat-resistant modifier: A15, A50B, A10 (Japan Zhongyuan).
MBS heat-resistant modifier: Mitsubishi H602, 605, 632.
In addition, there are ELIX200, 300; GEBlendex702, 703, 586, 975, etc.
6, adding inorganic filler to 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 powder and so on.
7, adding fiberglass to PVC
20%~30% glass fiber is added to PVC. The heat resistance can be increased to above 100 °C without adding (or adding less) plasticizer. Especially for long fiber reinforced PVC, the heat distortion temperature increases. More obvious.