Freeman Chemical Corporation

William L Carlstrom

Glenn R Svoboda

Gary L Maechtle

John T Suh

Ronald W Reineck

Richard T Stoehr

Low smoke isocyanurate modified polyurethane foams are prepared from polyols and a stoichiometric excess of reactive isocyanates providing an --NCO/--OH index of 1.3-3.0, preferably from 1.6-2.3. Catalysts for the trimerization reaction of the isocyanate to the isocyanurate form are employed. The polyol used in the present invention includes from 5-100% of a digestion product which is prepared by digesting polyalkylene terephthalate residues in organic polyols. The foams produced by the method of the present invention possess unexpected properties in such areas as flame spread, smoke, and low friability. The use of the polyols described above can substantially reduce product cost, allowing the isocyanurate modified polyurethane foams of the present invention to be utilized in commercial applications.

Low smoke isocyanurate modified urethane foam and method of making same

A flexible polyurethane foam having a low flame spread index is produced by combining polyol (preponderantly diol and/or triol) with polyisocyanate (preponderantly diisocyanate) in the presence of a foaming catalyst and a blowing agent. By combining at least 75% by weight of pentabromoethyl benzene, based upon the weight of the polyol, a flame spread index less than 150 can be achieved for the resulting foam in the ASTM test E-162-76. Significantly, polyurethane foams having a flame spread index less than 25 have been produced with this invention.

Flexible polyurethane foam having a low flame spread index

Rigid polyurethane foam is produced from polyisocyanate and polyol wherein 5-30% by weight of the polyol ingredient is a digestion product of polyalkylene terephthalate residues or scraps digested with organic polyols. The resulting rigid polyurethane foam exhibits uniform density and, when compared with a corresponding polyurethane foam which does not include the said digestion products, exhibits equivalent or superior physical strength properties. With fire retardant rigid polyurethane foams wherein the organic polyol ingredient includes halogenated organic polyols, use of 5-30% by weight of the said digestion product in the organic polyol ingredient, achieves a rigid fire retardant polyurethane foam having a lower flame spread and a lower smoke generation than a corresponding polyurethane foam which does not include the said digestion product. When fabricated in a closed mold, the present rigid polyurethane foam has a more uniform density, i.e., a higher core density, than corresponding rigid polyurethane foams which do not include the said digestion product.

Rigid polyurethane foam containing polyester residue digestion product

Polyisocyanate prepolymers for use in preparing polyurethane products elastomers, adhesives and foams, are prepared by combining (1) organic polyisocyanate with (2) polyols which are the hydroxyl-terminated digestion products of (a) waste or scrap polyalkylene terephthalate polymers and (b) organic polyols. Polyurethane products resulting from the polyisocyanate prepolymers exhibit useful and unexpected properties.

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West Bend, WI, United States of America

William L Carlstrom