Process for the production of radiation-crosslinked thermoplastic polyurethanes

US4762884A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Wilhelm Goyert · Leverkusen, DE
• Jurgen Winkler · Schwarzheide, DE
• Hermann Perrey · Krefeld, DE
• Herbert Heidingsfeld · Frechen, DE

Key dates

• Filing date: Apr 20, 1987
• Grant date: Aug 9, 1988
• Expiry date: Apr 20, 2007

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F299/06
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The invention is directed to a process for the production of polyurethanes suitable for thermoplastic processing comprising mixing PA1 I. at least 75% by weight of preformed thermoplastic polyurethane elastomers, or of a blend of PA2 (A) substantially bifunctional, compounds PA2 (B) substantially bifunctional chain-extending agents PA2 (C) organic diisocyanates and optionally PA2 (D) lubricants or other known additives said blend characterized in that it contains no peroxides and polymerization initiators which decompose into radicals under the effect of actinic light and further in that the molar ratio of the sum of said (A) and said (B) to said (C) is between 0.9 to 1.1, with PA1 II. (E) from 4 to 24% by weight of a crosslinking agent and PA1 III. (F) from 0.01 to 3% by weight of a polymerization inhibitor and/or an antioxidant, by adding said II and said III to said I at a temperature below 230.degree. C., and the cooling the mixture to below 130.degree. C. in less than 5 minutes in a continuous extruder and optionally granulating the resulting polyurethane.