Asbestos-cement product and process

Claim 2

THE PROCESS FOR MANUFACTURING DURABLE, WEATHERRESISTANT, NON-BLOCKING, NON-TACKY ASBESTOS-CEMENT PRODUCTS WHICH COMPRISES COATING THE SURFACE OF AN AUTOCLAVE STEAMCURED ASBESTOS-CEMENT SHEET WITH A WATER-DISPERSED PIGMENTED ACRYLIC POLYMER, DRYING SAID COATING TO A DEGREE SUCH THAT SAID COATING IS SUBSTANTIALLY DRY TO THE TOUCH BUT NOT CURED, APPLYING THEREOVER AND AQUEOUS COATING OF AN UNPIGMENTED MIXTURE OF ACRYLIC POLYMER AND POLYETHYLENE, SAID POLYETHYLENE COMPRISING AT LEAST ABOUT 5 PERCENT OF THE TOTAL WEIGHT OF SOLIDS OF SAID MIXTURE, AND SIMULTANEOUSLY CURING SAID ACRYLIC AND SAID ACRYLIC-POLYETHYLENE MIXTURE TO FORM A TOUGH COATING WITH A SURCFACE WHICH IS RELATIVELY SLIPPERY, NONTACKY AND NON-BLOCKING.

Claim 3

The process for manufacturing durable, weather-resistant, non-blocking, non-tacky asbestos-cement products which comprises coating the surface of an autoclave steam-cured asbestos-cement sheet with a water-dispersed pigmented acrylic polymer, drying said coating to a degree such that said coating is substantially dry to the touch but not cured, applying thereover an aqueous coating of an unpigmented mixture of acrylic polymer and polyethylene, said polyethylene comprising at least about 5 percent of the total weight of solids of said mixture, and simultaneously curing said acrylic and said acrylic-polyethylene mixture to form a tough coating with a surface which is relatively slippery, non-tacky and non-blocking.

Claim 4

The process for manufacturing durable, weather-resistant, non-blocking, non-tacky asbestos-cement products which comprises coating the surface of an autoclave steam-cured asbestos-cement sheet with a water-dispersed pigmented acrylic polymer, drying said coating to a degree such that said coating is substantially dry to the touch but not cured, applying thereover an aqueous coating of an unpigmented mixture of acrylic polymer and polyethylene, said polyethylene comprising at least about 5 percent of the total weight of solids of said mixture, and simultaneously curing said acrylic and said acrylic-polyethylene mixture to form a tough coating with a surface which is relatively slippery, non-tacky and non-blocking.

Claim 5

The process of claim 1 wherein said unpigmented acrylic-polyethylene coating is applied at a rate of about 0.2 to 1 gram of solids per square foot.

Claim 6

The process of claim 1 wherein said unpigmented acrylic-polyethylene aqueous coating is prepared by mixing a polyethylene emulsion and an acrylic emulsion in a ratio to form a mixture wherein the solids consist essentially from about 5 to 50 percent polyethylene and from about 95 to 50 percent acrylic.

Claim 7

An asbestos-cement shingle having firmly adhered to the asbestos-cement on one face thereof a cured substantially unitary dual coating consisting essentially of an inner coating of a pigmented polymer of the class consisting of acrylic and vinyl polymers and an outer coating of an unpigmented mixture of about 5 to 50 percent polyethylene and 95 to 50 percent of a polymer substantially harder than said polyethylene and of the class consisting of acrylic and vinyl polymers.

Claim 8

An asbestos-cement shingle having firmly adhered to the asbestos-cement on one face thereof a cured substantially unitary dual coating consisting essentially of an inner coating of a pigmented polymer of the class consisting of acrylic and vinyl polymers and an outer coating of an unpigmented mixture of about 5 to 50 percent polyethylene and 95 to 50 percent of a polymer substantially harder than said polyethylene and of the class consisting of acrylic and vinyl polymers.

Claim 9

An asbestos-cement single as defined in claim 4 wherein said pigmented polymer is a pigmented acrylic.

Claim 10

An asbestos-cement shingle as defined in claim 5 wherein said harder polymer is an unpigmented acrylic of a composition substantially the same as the acrylic of said pigmented acrylic.

Claim 11

An asbestos-cement shingle as defined in claim 5 wherein said inner coating and said outer coating have been simultaneously cured to form said unitary dual coating.

Claim 12

An asbestos-cement shingle as defined in claim 4 wherein said harder polymer is an acrylic.

Claim 13

An improved board package comprising at least two boards of the class consisting of asbestos-cement, lime-silica and asbestos-wood fiber-cement held firmly together in face-to-face, non-blocking relationship, said boards each having a dual coating firmly adhered onto a substrate of each said board substantially throughout the face surface of each said substrate, said dual coating of each said board comprising a pigmented plastic inner coating and a clear plastic outer coating, said outer coating of each said board consisting essentially of a mixture of from about 5 to 50 percent polyethylene and about 95 to 50 percent of a latex-formed polymer of relative hardness substantially greater than the hardness of said polyethylene.

Claim 14

An improved board package comprising at least two boards of the class consisting of asbestos-cement, lime-silica and asbestos-wood fiber-cement held firmly together in face-to-face, non-blocking relationship, said boards each having a dual coating firmly adhered onto a substrate of each said board substantially throughout the face surface of each said substrate, said dual coating of each said board comprising a pigmented plastic inner coating and a clear plastic outer coating, said outer coating of each said board consisting essentially of a mixture of from about 5 to 50 percent polyethylene and about 95 to 50 percent of a latex-formed polymer of relative hardness substantially greater than the hardness of said polyethylene.