| 摘要 |
Polypropylene with a narrow mol. wt. distribution is made by treating polypropylene contg. phenolic antioxidants and opt.phenolic light stabilizers in the molten state with 0.005-0.5 wt. % of a peroxide chosen from 2,5-dimethyl-2,5-bis(tert butylperoxy)-hexyne-1,3, 1,1,4,4,7,7-hexamethylcyclo-4,7-diperoxynon ane 1,3-bis(tert. butyl-peroxyisopropyl)-benzene, 3,3,6,6,9,9-hexamethyl-cyclo-1,2,4,5-tetraoxanonane, 2,5-dimethyl -2,5-bis (tert. butylperoxy)hexane and phthalideperoxide, at 180-300 degrees C for >=10 secs. The treatment may be carried out in a kneader, screw extruder, injection moulding machine etc. The named peroxides are effective in the presence of phenolic antioxidants and present no hazards to safety when used on an industrial scale |
