A study on the preparation of heat shrinkable polyethylene film

In the preparation of a heat shrinkable polyethylene(PE) film by radiation, effects of stretch ratio, radiation dose, and stretch temperature and velocity on percent shrinkage of the stretched film were studied. Percent shrinkage increased with increasing stretch ratio and radiation dose. The resin which has a high melt index showed higher shrinkage property and more effective elastic memory by irradiation. The resin having a low melt index, when it is elongated more slowly, had more increased percent shrinkage. With these results, it is concluded that to give a resin higher shrinkage property especially in case of the resin with a low melt index, it needs sufficient thermal conditions enough to be easily elongated. In addition, effects of crosslinking agent and various stabilizers on the radiation crosslinking of polyvinyl chloride (PVC) were studied. Triallyl cyanurate as crosslinking agent showed a considerable gel promoting effect and maximum gel fraction at the concentration of 20 PHR, marking 85% at 14 Mrad. Butyl tin maleate complex as a liquid-state stabilizer gave better stabilization effect against radiation than tribasic lead sulfate as a solid-state one. (author)