Process for the production of sheet-like structures

US4025579A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Hermann Gruber · Leverkusen, DE
• Alois Fehlbier
• Hans-Dieter Ruprecht · Neunburg vorm Wald, DE

Key dates

• Filing date: Sep 23, 1975
• Grant date: May 24, 1977
• Expiry date: Sep 23, 1995

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08L75/08
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present invention relates to a process for preparing elastic laminates by admixing elastomeric granules with a moisture hardenable polyurethane binder and hardening the binder. The binder is formulated to have a workable viscosity at room temperature and to avoid crystallization at temperatures above about 0.degree. C. The binder is the reaction product of polyisocyanates of the diphenyl methane series having at least 20 wt. % of 2,4'-diisocyanatodiphenyl methane and di- and/or trihydroxy polyethers. The invention also relates to the binder composition itself and a process for preparing it. The binder has a viscosity of about 1000 to 15,000 cP at 20.degree. C and an NCO content of about 5 to 15 wt. %. It is prepared at an NCO to OH ratio of about 2:1 to 15:1 and at about 15.degree. to 100.degree. C.