Rigid polyurethane foams containing lithium salts for energy absorbing applications

Claim 1

A method of preparing an energy absorbing rigid polyurethane open cell foamed article having a molded density of less than 2.8 pcf and a near constant compression strength of from about 10 percent to about 60 percent deflection at loads of less than 60 psi, comprising; A) packing an open or closed mold with a formulation at a packing ratio less than 1.7; B) allowing the formulation to react in a closed and optionally preheated mold, wherein the formulation ingredients comprise: i) an organic polyisocyanate; ii) a compound having at least two isocyanate reactive hydrogens; iii) a reactive blowing agent consisting essentially of water, formic acid, salts of formic acid, or mixtures thereof; iv) a urethane promoting catalyst; v) a surfactant; vi) a lithium salt of an organic material having 2 to 30 carbon atoms and at least one carboxylic acid as a cell opening agent; and C) demolding and curing said article.

Claim 2

A method of preparing an energy absorbing rigid polyurethane open cell foamed article having a molded density of less than 2.8 pcf and a near constant compression strength of from about 10 percent to about 60 percent deflection at loads of less than 60 psi, comprising; A) packing an open or closed mold with a formulation at a packing ratio less than 1.7; B) allowing the formulation to react in a closed and optionally preheated mold, wherein the formulation ingredients comprise: i) an organic polyisocyanate; ii) a compound having at least two isocyanate reactive hydrogens; iii) a reactive blowing agent consisting essentially of water, formic acid, salts of formic acid, or mixtures thereof; iv) a urethane promoting catalyst; v) a surfactant; vi) a lithium salt of an organic material having 2 to 30 carbon atoms and at least one carboxylic acid as a cell opening agent; and C) demolding and curing said article.

Claim 15

A method of preparing a reactive blown polyurethane open cell foamed article having a free rise density of 2.8 pcf or less obtained by mixing a formulation comprising: i) an organic polyisocyanate, ii) a compound having at least two isocyanate reactive hydrogens, iii) less than 8 parts by weight reactive blowing agent consisting essentially of water, formic acid, salts of formic acid, or mixtures thereof, based on 100 parts by weight of polyol, iv) a urethane promoting catalyst; v) a surfactant, and vi) a lithium salt of an organic material having 2 to 20 carbon atoms and at least one carboxylic acid as a cell opening agent; and allowing the mixture to react and foam.

Claim 16

A method of preparing a reactive blown polyurethane open cell foamed article having a free rise density of 2.8 pcf or less obtained by mixing a formulation comprising: i) an organic polyisocyanate, ii) a compound having at least two isocyanate reactive hydrogens, iii) less than 8 parts by weight reactive blowing agent consisting essentially of water, formic acid, salts of formic acid, or mixtures thereof, based on 100 parts by weight of polyol, iv) a urethane promoting catalyst; v) a surfactant, and vi) a lithium salt of an organic material having 2 to 20 carbon atoms and at least one carboxylic acid as a cell opening agent; and allowing the mixture to react and foam.