The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 01, 1999
Filed:
Oct. 06, 1997
Joachim Berthold, Kelkheim, DE;
Ludwig Bohm, Hattersheim, DE;
Werner Breuers, Eppstein, DE;
Johannes Friedrich Enderle, Frankfurt, DE;
Manfred Fleissner, Eschborn, DE;
Rainer Lecht, Kelkheim, DE;
Hartmut Luker, Hofheim, DE;
Ulrich Schulte, Kelkheim, DE;
Heiner Bromstrup, Heidesheim, DE;
Hoechst Aktiengesellschaft, , DE;
Abstract
The invention relates to a high strength pipe of ethylene polymer having a bimodal molecular weight distribution. Such pipe has a stress cracking resistance of .gtoreq.1400 h, a fracture toughness of .gtoreq.7 mJ/mm.sup.2 and a modulus of creep in flexure, measured according to DIN 54852-Z4, of .gtoreq.1100 N/mm.sup.2. The pipe according to the invention is produced from an ethylene polymer in which the ratio of weight of the low molecular weight fraction to the weight of the higher molecular weight fraction is in the range from 0.5 to 2.0 and which has a melt flow index MFI.sub.5/190.degree. C. of .ltoreq.0.35 g/10 min. It is particularly suitable for the transportation of gases and water.