Cured polyurethane compositions containing epoxy resins

Claim 1

A cured polyurethane composition characterized by its tensile strength at 25° C. Being resistant to hydrolysis degradation when immersed in distilled water at 158° F. for 14 days prepared by the method which consists of reacting a polyurethane reaction mixture, containing sufficient diamine curative therefor, in the presence of an excess of an epoxy resin, said method consisting essentially of (A) mixing in a solvent, in order to provide a fluid mixture or solution containing about 40 to about 95 percent solids, selected from benzene, xylene, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone and diisobutyl ketone (1) an epoxy resin derived from epichlorohydrin and a bis phenol and having an epoxide equivalent in the range of about 150 to about 525, (2) a prepolymer of at least one organic diisocyanate and at least one reactive hydrogen-containing polymeric material having a molecular weight in the range of from about 700 to about 5,000 selected from polyester polyols, polyether polyols and hydroxyl terminated unsaturated polymeric polyols with a hydroxyl functionality of about 2 to about 3 where the ratio of the diisocyanate of the reactive hydrogens of the reactive hydrogen-containing polymeric material is from about 1.1/1 to about 3.5/1, and (3) a primary diamine curative where the ratio of amino groups of the curative to isocyanato groups in excess of the reactive hydrogens of the reactive hydrogen-containing polymeric material is from about 0.5/1 to about 1.1/1 and where the said polyurethane composition contains from about 2 to about 15 weight percent and at least a sufficient amount to give about a 5 to about a 50 equivalent percent excess of epoxide groups relative to the total excess of said amino groups of the curative over the said isocyanato groups, wherein said epoxy resin is contacted with said primary diamine only at or just prior to preparing said reaction mixture, and (B) substantially simultaneously removing the solvent from the mixture and reacting the prepolymer with the diamine curative in the presence of the epoxy resin at a temperature in the range of about 20° C. to about 100° C.

Claim 3

A method of preparing a polyurethane composition having a property of being resistant to hydrolysis degradation by immersion in distilled water at 158° F. for 14 days by reacting a polyurethane reaction mixture, containing sufficient diamine curative therefor, in the presence of an excess of an epoxy resin, said method consisting essentially of (A) mixing in a solvent, in order to provide a fluid mixture or solution containing about 40 to about 95 percent solids, selected from benzene, xylene, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone and diisobutyl ketone (1) an epoxy resin derived from epichlorohydrin and a bis phenol and having an epoxide equivalent in the range of about 150 to about 525, (2) a prepolymer of at least one organic diisocyanate and at least oen reactive hydrogen-containing polymeric material having a molecular weight in the range of from about 700 to about 5,000 selected from polyester polyols, polyether polyols and hydroxyl terminated unsaturated polymeric polyols with a hydroxyl functionality of about 2 to about 3 where the ratio of the diisocyanate to the reactive hydrogens of the reactive hydrogen-containing polymeric material is from about 1.1/1 to about 3.5/1, and (3) a primary diamine curative where the ratio of amino groups of the curative to isocyanato groups in excess of the reactive hydrogens of the reactive hydrogen-containing polymeric material is from about 0.5/1 to about 1.1/1 and where the said polyurethane composition contains from about 2 to about 15 weight percent and at least a sufficient amount to give about a 5 to about a 50 equivalent percent excess of epoxide groups relative to the total excess of said amino groups of the curative over the said isocyanato groups, wherein said epoxy resin is contacted with said primary diamine only at or just prior to preparing said reaction mixture, and (B) substantially simultaneously removing the solvent from the mixture and reacting the prepolymer with the diamine curative in the presence of the epoxy resin at a temperature in the range of about 20° C. to about 100° C.

Claim 4

A method of preparing a polyurethane composition having a property of being resistant to hydrolysis degradation by immersion in distilled water at 158° F. for 14 days by reacting a polyurethane reaction mixture, containing sufficient diamine curative therefor, in the presence of an excess of an epoxy resin, said method consisting essentially of (A) mixing in a solvent, in order to provide a fluid mixture or solution containing about 40 to about 95 percent solids, selected from benzene, xylene, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone and diisobutyl ketone (1) an epoxy resin derived from epichlorohydrin and a bis phenol and having an epoxide equivalent in the range of about 150 to about 525, (2) a prepolymer of at least one organic diisocyanate and at least oen reactive hydrogen-containing polymeric material having a molecular weight in the range of from about 700 to about 5,000 selected from polyester polyols, polyether polyols and hydroxyl terminated unsaturated polymeric polyols with a hydroxyl functionality of about 2 to about 3 where the ratio of the diisocyanate to the reactive hydrogens of the reactive hydrogen-containing polymeric material is from about 1.1/1 to about 3.5/1, and (3) a primary diamine curative where the ratio of amino groups of the curative to isocyanato groups in excess of the reactive hydrogens of the reactive hydrogen-containing polymeric material is from about 0.5/1 to about 1.1/1 and where the said polyurethane composition contains from about 2 to about 15 weight percent and at least a sufficient amount to give about a 5 to about a 50 equivalent percent excess of epoxide groups relative to the total excess of said amino groups of the curative over the said isocyanato groups, wherein said epoxy resin is contacted with said primary diamine only at or just prior to preparing said reaction mixture, and (B) substantially simultaneously removing the solvent from the mixture and reacting the prepolymer with the diamine curative in the presence of the epoxy resin at a temperature in the range of about 20° C. to about 100° C.