Method of manufacturing a foamed urethane structural product having high and low density portions

Claim 2

PROCESS FOR MANUFACTURING A HIGH QUALITY MOLDED URETHANE STRUCTURAL PROCUCT WHICH COMPRISES INTRODUCING A RELATIVELY HIGH DENSITY FOAMABLE URETHANE MIXTURE INTO A MOVING MOLD FROM A FIRST SPRAY APPLICATOR, SUBSEQUENTLY CONTINUOUSLY INTRODUCING ADDITIONAL RELATIVELY LOW DENSITY FOAMABLE URETHANE MIXTURE INTO SAID MOLD FROM A SECOND SPRAY APPLICATOR IN A MANNER THAT THE SPRAY FROM SAID SECOND APPLICATOR SLIGHTLY OVERLAPS THE SPRAY FROM SAID FIERS APPLICATOR, AND IN A MANNER THAT THE FOAMABLE URETHANE MIXTURE FROM SAID SECOND APPLICATOR COMPLETELY COVERS THE FOAMABLE URETHANE MIXTURE FROM SAID FIRST APPLICATOR IN SAID MOLD.

Claim 3

Process as defined in claim 1 wherein the foamable urethane mixture from said first applicator has a density in the range from about 10 to 30 lbs/ft3 and wherein the foamable urethane mixture from said second applicator has a density in the range from about 2 to 4 lbs/ft3.

Claim 4

Process as defined by claim 2 wherein the thickness of the applied relatively high density foamable urethane mixture is about one-sixteenth inch to one-half inch and wherein the thickness of the applied relatively low density foamable urethane mixture is about one-fourth inch to 1 inch.

Claim 5

Process as defined by claim 1 wherein the foamable urethane mixture from said second applicator overlaps the foamable urethane mixture from said first applicator by about one-fourth inch to 1 inch.

Claim 6

Process as defined by claim 1 wherein a primer barrier coat is first introduced into said mold.

Claim 7

Process as defined by claim 5 wherein said barrier coat is dissolved in methyl isobutyl ketone and applied to a thickness of about 0.0002 inch to 0.0005 inch.

Claim 8

Process as defined by claim 1 wherein said mold is first heated to a temperature in the range from about 120*F to 160*F.

Claim 9

Process for manufacturing a high quality molded urethane structural product which comprises preheating a flexible moving mold to a temperature in the range from about 120*F to 160*F, introducing into said mold a relatively high density foamable urethane mixture having a density in the range from about 10 to 30 lb/ft3, then introducing a relatively low density foamable urethane mixture into said mold from a second spray applicator, said relatively low density foamable mixture having a density in the range from about 2 to 4 lb/ft3, and in a manner that the spray from said second applicator slightly overlaps the spray from said first applicator, and in a manner that the foamable urethane mixture from said second applicator completely covers the foamable urethane mixture from said first applicator in said mold, applying a hot air blast to said foamable urethane mixture as they expand in a manner to retard foam expansion, and thereafter receiving said molded urethane products.

Claim 10

Process for manufacturing a high quality molded urethane structural product which comprises preheating a flexible moving mold to a temperature in the range from about 120*F to 160*F, introducing into said mold a relatively high density foamable urethane mixture having a density in the range from about 10 to 30 lb/ft3, then introducing a relatively low density foamable urethane mixture into said mold from a second spray applicator, said relatively low density foamable mixture having a density in the range from about 2 to 4 lb/ft3, and in a manner that the spray from said second applicator slightly overlaps the spray from said first applicator, and in a manner that the foamable urethane mixture from said second applicator completely covers the foamable urethane mixture from said first applicator in said mold, applying a hot air blast to said foamable urethane mixture as they expand in a manner to retard foam expansion, and thereafter receiving said molded urethane products.

Claim 11

Process as defined in claim 8 wherein said relatively high density foamable urethane mixture is first applied to a thickness in the range of about one-sixteenth inch to one-fourth inch and wherein said relatively low density foamable urethane mixture is first applied to a thickness in the range of about one-fourth inch to 1 inch and wherein said mixtures expand to a thickness of about 3 inches, said mixtures being applied in a manner that the spray from said second applicator overlaps the spray from said first applicator and wherein the intensity of the hot air blast which retards foam expansion decreases in the direction of the movement of the mold.

Claim 12

Process as defined by claim 9 wherein the relatively high density foamable urethane mixture has a density of about 25 lb/ft3 and wherein the relatively low density foamable urethane mixture has a density of about 3 lb/ft3.

Claim 13

Process for the manufacture of a high quality molded urethane structural product which comprises preheating a moving mold, introducing a relatively high density foamable urethane mixture into said moving mold from a first spray applicator, subsequently continuously introducing a relatively low density urethane mixture into said mold from a second spray applicator in a manner that the spray from said second applicator slightly overlaps the spray from said first applicator, and in a manner that the foamable urethane mixture from said second applicator completely covers the foamable urethane mixture from said first applicator in said mold, and maintaining forming conditions to secure an Expansion increase of said relatively high density foamable urethane mixture to about 15% to 20% of its original volume and expansion increase of said relatively low density foamable urethane mixture to about 20 to 50 times its original volume, and subjecting said foamable urethane mixtures in said mold to an air blast, the intensity of which decreases in the direction of movement of said moving mold.

Claim 14

Process for the manufacture of a high quality molded urethane structural product which comprises preheating a moving mold, introducing a relatively high density foamable urethane mixture into said moving mold from a first spray applicator, subsequently continuously introducing a relatively low density urethane mixture into said mold from a second spray applicator in a manner that the spray from said second applicator slightly overlaps the spray from said first applicator, and in a manner that the foamable urethane mixture from said second applicator completely covers the foamable urethane mixture from said first applicator in said mold, and maintaining forming conditions to secure an Expansion increase of said relatively high density foamable urethane mixture to about 15% to 20% of its original volume and expansion increase of said relatively low density foamable urethane mixture to about 20 to 50 times its original volume, and subjecting said foamable urethane mixtures in said mold to an air blast, the intensity of which decreases in the direction of movement of said moving mold.

Claim 15

Process as defined in claim 11 wherein subsequent to said air blast a reinforcing sheet is securely positioned above said relatively low density foamable urethane mixture, followed by the introduction of a second relatively low density foamable urethane mixture onto said reinforcing sheet, followed by the introduction of a second relatively high density foamable urethane mixture in a manner to overlap the introduction of said second relatively low density foamable urethane mixture, and subjecting said second mixtures to a final air blast which decreases in the direction of movement of said moving mold.

Claim 16

Process as defined by claim 12 wherein said overlaps are about one-fourth inch to 1 inch, wherein said relatively high density foamable urethane mixtures are about 10 to 30 lbs ft3 and said relatively low density foamable urethane mixtures are about 2 to 4 lbs ft3, and wherein said final air blast decreases to about 10% to 40% of the intensity of the blast when said second mixtures first contact said final air blast.