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:
Feb. 02, 1988
Filed:
Jun. 26, 1986
David A Harbourne, Kingston, CA;
Evelyn M Lundhild, Kingston, CA;
Du Pont Canada Inc., Mississauga, CA;
Abstract
A fire-retardant sheet material, the manufacture thereof and a fire-retardant polymer composition are disclosed. The sheet is manufactured from a composition of polyethylene, 55 to 75% by weight of the composition of alumina trihydrate and/or magnesium hydroxide, and optionally zinc borate and/or calcium carbonate, at least 2% by weight of the composition being in the form of a graft copolymer with an ethylenically unsaturated carboxylic acid or anhydride. The composition has a melt index of 0.05 to 4.0 dg/min. In an embodiment, the graft copolymer has a shear viscosity at 200.degree. C. and a shear rate of 400 sec.sup.-1 that is not more than 50% of that of the polyethylene. The sheet material may be used for, in particular, ceiling tile. In embodiments of the composition, 60 to 90% by weight may be alumina trihydrate and/or magnesium hydroxide, and optionally zinc borate and/or calcium carbonate.