Heat shrinkable high mol. wt. polyethylene - obtd. by irradiating and stretching polyethylene gel and used to form spun or extruded products

摘要

Heat shrinkable material based on high molecular polyethylene is claimed and obtd. by (a) thermo reversible gelation of a soln. (I) of a linear polyethylene having Mw of at least 4x10 power 5 to form a gel having the same compsn. as the original soln; and (b) irradiation of the gel with simultaneous or subsequent stretching at a stretch ratio of at least 15. A heat shrinkable article is also claimed obtd by: (1) spinning or extruding (I) into a solvent contg. article at above the gel temp. of (I); (2) cooling the obtd. article to below the gel temp. while forming a homogeneous polymer gel structure having the same compsn. as the original soln. (I). (3) irradiating the article while in the gel state; and (4) stretching the article either during or after the irradiation with a total stretch ratio of at least 15, opt. of at least partial removal of the solvent.