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:
May. 28, 1985
Filed:
May. 25, 1982
Helmut Landgraf, Duisburg, DE;
Walter Stucke, Ratingen, DE;
Mannesmann Aktiengesellschaft, Duesseldorf, DE;
Abstract
A method for making a polyethylene jacket on steel pipes including applying an inner foil upon the preheated steel pipe for purposes of providing adhesion thereto and of an outer, jacketing foil, also to be applied through a duel extrusion head which is to be heated to an operating temperature of approximately 170.degree. C. During extrusion, a gaseous mixture is fed to the space between the surface of the tube to be jacketed and the inner foil, which gaseous mixture consists of air to which a reactive gaseous component, such as ozone, has been added; the inner foils is made from a material so that the gaseous mixture reacts under the formation of groups which provide adhesion, such as carboxylic groups.