Patent ID: 11400639

Abstract:
The invention relates to a process for the production of a high strength transparent high density polyethylene article comprising the steps of (i) heating a high density polyethylene (HDPE) to a temperature above the melting temperature (Tm) of the HDPE; (ii) molding the heated HDPE obtained in step (i) to form a hot molded HDPE article; (iii) cooling the hot molded HDPE article to a temperature below Tm to form a melt-crystallized HDPE article; (iv) stretching the melt-crystallized HDPE article to a total draw ratio of at least 5 comprising at least one stretching step of the article at a temperature T1 below the melting temperature Tm to a draw ratio (DR1) of at least 2 to form an oriented HDPE article, wherein the HDPE has a melt flow index (MFI) measured at 21.6 kg and 190° C. according to ASTM D1238 of at most 1.5 g/I Omin, an isotropic density measured according to ISO 1 183-1 A of at most 0.955 g/cm3 and a Tm measured according to ISO 1 1357-3 of greater than 130° C. The invention also relates to high strength transparent HDPE articles and products comprising the high strength transparent HDPE article such as ballistic resistant articles, visors, car parts, train parts, plane parts, windshields, windows and radomes.