Abstract Polyurethane foam composites characterized by at least one layer of flexible, densified polyurethane foam are prepared by placing a plurality of layers of polyurethane foam, including at least alternate layers of partially cured polyurethane foam, in contiguous relationship, thereby forming a composite structure, maintaining the composite for a critical period of time at a critical environmental temperature, applying a compressive force to the composite to reduce its volume by between about two-thirds and one-tenth of its original volume, removing the compressive force and completeing the cure. These polyurethane foam composites are particularly useful for cushioning applications. The partially cured polyurethane foam bonds to adjacent layers during the process.
The process of claim 1 wherein the partially cured polyurethane foam is maintained at an environmental temperature between about 45* and about 200* F. where the period of time between completion of the rise and application of the compressive force is between about 0 and 2.5 minutes; 45* and about 100* F. where said period of time is between about 2.5 and about 5 minutes; and 45* and about 85* F. where said period of time is between about 5 and about 10 minutes.
Claim 2
Dependent Claim
57 words
The process of claim 1 wherein the compressive force is applied at a period of time between about 0 and about 10 minutes after completion of the rise of said partially cured polyurethane foam, and where said partially cured polyurethane foam is maintained at an environmental temperature between about 70* and about 110* F. for said period.
Claim 3
Dependent Claim
22 words
The process of claim 1 wherein the polyol employed in the preparation of said partially cured polyurethane foam is a polyether polyol.
Claim 4
Dependent Claim
27 words
The process of claim 4 wherein said polyether polyol is an oxyalkylated polyhydric alcohol having a molecular weight in the range between about 700 and about 10,000.
Claim 5
Dependent Claim
12 words
The process of claim 5 wherein said polyether polyol is oxypropylated glycerin.
Claim 6
Dependent Claim
21 words
The process of claim 4 wherein the foaming agent employed in the preparation of said partially cured polyurethane foam is water.
Claim 7
Dependent Claim
29 words
The process of claim 7 wherein the reaction catalyst employed in the preparation of said partially cured polyurethane foam is a mixture of an amine and a stannous salt.
Claim 8
Dependent Claim
29 words
The process of claim 4 wherein the foaming agent employed in the preparation of said partially cured polyurethane foam is a mixture of water and an organic foaming agent.
Claim 9
Dependent Claim
29 words
The process of claim 9 wherein the reaction catalyst employed in the preparation of said partially cured polyurethane foam is a mixture of an amine and a stannous salt.
Claim 10
Dependent Claim
41 words
The process of claim 1 wherein said partially cured polyurethane foam comprises oxypropylated glycerin having a molecular weight in the range between about 1,000 and about 6, 000, toluene diisocyanate, water and a mixture of an amine and a stannous salt.
Claim 11
Dependent Claim
36 words
The process of claim 1 wherein a plurality of partially cured polyurethane foams are allowed to rise and subsequently placed in contiguous relationship to form the composite structure prior to the application of the compressive force.