ISOCYANATE MODIFIED CELLULOSE PRODUCTS AND METHOD FOR THEIR MANUFACTURE

• Main Author: HUNTER, FRANK, R
• Format: Patent
• Language: English
• Published: 07.07.1993
• Edition: 5
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; IMPREGNATING OR COATING OF PAPER; LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PAPER NOT OTHERWISE PROVIDED FOR; PAPER-MAKING; PERFORMING OPERATIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; PRODUCTION OF CELLULOSE; PULP COMPOSITIONS; TEXTILES; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G

The invention is a method of making a cellulose based polymeric material and the products of the invention. A cellulosic substrate is impregnated with an essentially uncatalyzed polyfunctinal isocyanate and pressed at elevated temperature and pressure. The substrate may be a chemical or thermomechanical pulp or paper while the isocyanate is preferably diphenylmethane diisocyanate or its oligomers. Pressing conditions are preferably in the range of about 150 DEG -245 DEG C. at pressures in the range of about 2700-8300 kPa for times less than 2 minutes. Moisture content of the cellulosic substrate is not highly critical and may be as high as 7% without adverse effects. The product is especially useful as overlays and for forming strong, water resistant laminates which can be molded in either flat or three dimensional forms.