Basf Wyandotte Corporation

Robert L Schaaf

Peter T Kan

Moses Cenker

William E Volz

Lewis N Medaugh

This invention relates to a process for utilizing the sediments in pure MDI which comprises

Process for using sediments developed during storage of pure MDI

Highly stable liquid 4,4'-diphenylmethane diisocyanate (MDI) containing MDI-carbodiimide adducts are prepared by heating MDI at a temperature of from 180.degree. C. to 250.degree. C. for a period of from one hour to ten hours in the presence of tris(chloromethyl)phosphine oxide and thereafter equilibrating the adduct formation. Equilibration can occur by any of several methods, i.e., by cooling the composition to a temperature of from 60.degree. C. to 90.degree. C. within twenty minutes, maintaining the composition at this temperature for a period of from one hour to four hours and thereafter cooling the composition to room temperature or by cooling the composition to a temperature less than 100.degree. C. within twenty minutes, further cooling to room temperature, and maintaining the composition at room temperature for one week to two weeks. The resulting compositions have very low sediment contents and are particularly useful in the preparation of microcellular polyurethane foams.

Stable liquid carbodiimide-containing polyisocyanate compositions

Polyurethane foams are prepared employing as the polyisocyanate ingredient a highly stable liquid 4,4'-diphenylmethane diisocyanate (MDI) containing MDI-carbodiimide adducts prepared by heating MDI at a temperature of from 180.degree. C. to 250.degree. C. for a period of from one hour to ten hours in the presence of tris(chloromethyl)phosphine oxide and thereafter equilibrating the adduct formation. Equilibration can occur by any of several methods, i.e., by cooling the composition to a temperature of from 60.degree. C. to 90.degree. C. within twenty minutes, maintaining the composition at this temperature for a period of from one hour to four hours and thereafter cooling the composition to room temperature or by cooling the composition to a temperature less than 100.degree. C. within twenty minutes, further cooling to room temperature, and maintaining the composition at room temperature for one week to two weeks. The resulting foams exhibit enhanced physical properties, particularly tensile and tear strength and lower heat sag.

Polyurethane foams prepared from highly stable liquid

Highly stable liquid 4,4'-diphenylmethane diisocyanate (MDI) containing MDI-carbodiimide adducts are prepared by (a) heating MDI at a temperature of from 60.degree. C. to 120.degree. C. for a period of from one hour to ten hours in the presence of tris(chloromethyl)phosphine oxide, (b) stopping the carbodiimide formation by adding thereto a quenchant selected from the group consisting of magnesium chloride hydrate, stannous chloride and trichlorosilane, (c) heating the reaction mixture at a temperature between 60.degree. C. and 120.degree. C. for a period of from 0.5 hour to 6.0 hours, and (d) cooling to room temperature. The resulting compositions are highly stable and may be advantageously employed in the preparation of polyurethane compositions.

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Wyandotte, MI, United States of America

Robert L Schaaf