Flexible molded foam and process for preparation thereof

Claim 2

A flexible molded foam comprising: (a) a surface layer of elastic thin film having a thickness of 7 to 50μ, which consists essentially of a polyurethane linear polymer having a number-average molecular weight of 25,000 to 55,000; (b) an intermediate reinforcing layer of elastic film having a thickness of 100 to 500μ, which comprises a three-dimensionally crosslinked polyurethane; and (c) a core layer which comprises a semi-rigid polyurethane foam having an apparent density of 0.03 to 0.30 g/cm 3 ; wherein said layers are integrally molded in a desirable shape and wherein the surface layer and the intermediate reinforcing layer are bonded very tightly by free isocyanate groups on the molecule ends of the polyurethane linear polymer layer present prior to curing.

Claim 3

A flexible molded foam as set forth in claim 1 wherein the polyurethane linear polymer of the surface layer is obtained by reaction between a bifunctional polyol and an aliphatic diisocyanate.

Claim 4

A flexible molded foam as set forth in claim 2 wherein the polyurethane linear polymer of the surface layer is obtained by reacting a bifunctional polyol having a molecular weight of 1,000 to 3,000 with an aliphatic diisocyanate excessed slightly to the stoichiometric amount.

Claim 5

A flexible molded foam as set forth in claim 1 wherein the elastic thin film surface layer has a 100% tensile modulus of 0.8 to 1.4 kg/mm 2 .

Claim 6

A flexible molded foam as set forth in claim 1 wherein the three-dimensioally crosslinked polyurethane of the intermediate reinforcing layer is one obtained by reacting an organic diisocyanate with a polyol, at least a part of which is composed of a trifunctional polyol or a polyol having a higher functionality.

Claim 7

A flexible molded foam as set forth in claim 1 wherein the 100% tensile modulus of the elastic film of intermediate reinforcing layer is 0.3 to 0.8 kg/mm 2 .

Claim 8

A flexible molded foam as set forth in claim 1 wherein the elongation of the elastic film of intermediate reinforcing layer is 200 to 350%.

Claim 9

A flexible molded foam as set forth in claim 1 wherein the surface hardness as measured by a C-type hardness meter is 30° to 55°.

Claim 10

A flexible molded foam as set forth in claim 1 wherein a reinforcing element of metal or plastic is also integrally molded with said layers.

Claim 11

A process for the preparation of flexible molded foam which comprises the steps of: (a) coating the surface of mold having a desirable shape with a solvent diluted solution having a solid content of 5 to 20% which consists essentially of a polyurethane linear polymer having a number average molecular weight of 25,000 to 55,000 and free isocyanate groups on the molecule ends thereof, coloring pigments and other additives to form a surface layer, so that the amount of said solid content on the mold is 0.7 to 6.5 mg/cm 2 ; (b) coating said surface layer with a solvent diluted solution having a solid content of 30 to 80% which contains a polyurethane prepolymer having free isocyanate groups on the molecule ends thereof, which obtained by reacting a first polyol having an average functional group number of 2.0 to 3.0 with organic diisocyanates, a second polyol having an average functional group number of 2.0 to 3.0, a coloring pigment and other additives to form an intermediate reinforcing layer so that the amount of solid content on said surface layer is 10 to 75 mg/cm 2 ; and further (c) pouring a semi-rigid polyurethane foam-forming liquid comprising polyols, polyisocyanates and other aditives into the mold to form a core layer; (d) foaming and curing, whereby said surface layer, intermediate reinforcing layer and core layer are simultaneously formed into an integrally molded foam; and finally (e) removing said molded foam from the mold.

Claim 12

A process for the preparation of flexible molded foam which comprises the steps of: (a) coating the surface of mold having a desirable shape with a solvent diluted solution having a solid content of 5 to 20% which consists essentially of a polyurethane linear polymer having a number average molecular weight of 25,000 to 55,000 and free isocyanate groups on the molecule ends thereof, coloring pigments and other additives to form a surface layer, so that the amount of said solid content on the mold is 0.7 to 6.5 mg/cm 2 ; (b) coating said surface layer with a solvent diluted solution having a solid content of 30 to 80% which contains a polyurethane prepolymer having free isocyanate groups on the molecule ends thereof, which obtained by reacting a first polyol having an average functional group number of 2.0 to 3.0 with organic diisocyanates, a second polyol having an average functional group number of 2.0 to 3.0, a coloring pigment and other additives to form an intermediate reinforcing layer so that the amount of solid content on said surface layer is 10 to 75 mg/cm 2 ; and further (c) pouring a semi-rigid polyurethane foam-forming liquid comprising polyols, polyisocyanates and other aditives into the mold to form a core layer; (d) foaming and curing, whereby said surface layer, intermediate reinforcing layer and core layer are simultaneously formed into an integrally molded foam; and finally (e) removing said molded foam from the mold.

Claim 13

The process according to claim 10 wherein the linear polyurethane forming the surface layer is obtained by reacting a bifunctional polyol with an aliphatic diisocyanate.

Claim 14

The process according to claim 11 wherein the bifunctional polyol is a polyester diol having a molecular weight of 1,000 to 3,000 and containing two hydroxyl groups on the molecule ends thereof.

Claim 15

The process according to claim 11 wherein the aliphatic diisocyanate is at least one member selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate and m-xylene diisocyanate.

Claim 16

The process according to claim 10 wherein the first polyol is reacted with the organic diisocyanate in an amount of 1.5 to 4.0 equivalents per an equivalent of the first polyol.

Claim 17

The process according to claim 10 wherein the average equivalent weight per each functional group of the first and second polyols is 200 to 1,500.

Claim 18

The process according to claim 10 wherein the first polyol is a bifunctional polyol and at least a part of the second polyol is a trifunctional group.

Claim 19

The process according to claim 10 wherein at least a part of the first polyol is a trifunctional polyol and the second polyol is a bifunctional polyol.

Claim 20

The process according to claim 10 wherein the organic diisocyanate is an aliphatic or aromatic diisocyanate.

Claim 21

The process according to claim 10 wherein the organic diisocyanate is at least one member selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate, m-xylene diisocyanate, phenylene diisocyanate, tolulene diisocyanate, diphenylmethane diisocyanate and napththalene diisocyanate.

Claim 22

The process according to claim 10 wherein the free isocyanate group content in the urethane prepolymer is 2.5 to 7.5%.

Claim 23

The process according to claim 10 wherein the semi-rigid polyurethane foam-forming liquid is poured in the mold in an amount so that the volume of the foam obtained by blowing the foam-forming liquid in an open vessel is not larger than 5.5 times the volume of the inner cavity of the mold.

Claim 24

The process according to claim 10 wherein the semi-rigid polyurethane foam-forming liquid does not contain a halogenated hydrocarbon as a blowing agent in an amount exceeding 10%.

Claim 25

The process according to claim 10 wherein the temperature of the mold is higher than 35° C. when the semi-rigid polyurethane foam-forming liquid is poured into the mold.

Claim 26

A flexible molded foam as set forth in claim 1 wherein the surface layer and intermediate layer are chemically bonded by free isocyanate groups on the molecule ends of the polyurethane linear polymer of the surface layer.

Claim 27

The process according to claim 10, wherein the curing of step (d) chemically bonds the surface layer to the intermediate layer by the free isocyanate groups on the molecule ends of the polyurethane linear polymer defined by step (a).

Claim 28

A flexible molded foam comprising: (a) a surface layer of elastic thin film having a thickness of 7 to 50μ, which consists essentially of a polyurethane polymer having a number average molecular weight of 25,000-55,000; (b) an intermediate reinforcing layer of elastic film having a thickness of 100 to 500μ, which comprises a three-dimensionally cross-linked polyurethane; and (c) a core layer which comprises a semi-rigid polyurethane foam having an apparent density of 0.03 to 0.30 g/cm 3 ; wherein said layers are integrally molded in a desirable shape and wherein the surface layer has free isocyanate groups on the molecule ends of the polyurethane linear polymer prior to curing.

Claim 29

A flexible molded foam comprising: (a) a surface layer of elastic thin film having a thickness of 7 to 50μ, which consists essentially of a polyurethane polymer having a number average molecular weight of 25,000-55,000; (b) an intermediate reinforcing layer of elastic film having a thickness of 100 to 500μ, which comprises a three-dimensionally cross-linked polyurethane; and (c) a core layer which comprises a semi-rigid polyurethane foam having an apparent density of 0.03 to 0.30 g/cm 3 ; wherein said layers are integrally molded in a desirable shape and wherein the surface layer has free isocyanate groups on the molecule ends of the polyurethane linear polymer prior to curing.