Offset printing blanket

Claim 2

AN OFFSET PRINTING BLANKET CONSISTING ESSENTIALLY OF A. 3-10 MILS OF A VOID-FREE PRINTING LAYER OF AN ELASTOMERIC MATERIAL HAVING A SHORE A HARDNESS OF 30-60 DUROMETER FIRMLY ADHERED TO B. A POLYESTER FILM ABOUT 2-6 MILS IN THICKNESS HAVING A TENSILE STRENGTH OF 20,::: TO 180,000 POUNDS PER SQUARE INCH AND FIRMLY ADHERED TO C. A SOFT HIGHLY RESILIENT VOID-FREE RUBBER BACKING LAYER ABOUT 20 TO 65 MILS THICK FIRMLY ADHERED TO D. FIBROUS BACKING SHEET, WHEREIN THE BLANKET HAS A MODULUS OF ELASTICITY OF 1 TO 4 X 10-7 DYNES PER CENTIMETER AND A BAYSHORE RESILIENCE OF 30-50 PERCENT MEASURED ACCORDING TO ASTM-D-2632-67 AND A PERMANENT SET OF 1-3 PERCENT MEASURED ACCORDING TO ASTM-39561 METHOD A.

Claim 3

The printing blanket of claim 1 in which the elastomeric material is an acrylonitrile/butadiene copolymer and the polyester film is a polyethylene terephthalate film.

Claim 4

The printing blanket of claim 2 in which the resilient rubber backing layer is an epichlorohydrin rubber.

Claim 5

The printing blanket of claim 1 in which a fibrous backing sheet is a woven cotton material firmly adhered to the rubber backing layer with an epichlorohydrin elastomer.

Claim 6

The printing blanket of claim 4 in which the fabric backing layer is cotton duck.

Claim 7

The printing blanket of claim 3 in which the fibrous backing sheet is a spun bonded non-woven fabric.

Claim 8

The printing blanket of claim 6 in which the fibrous backing sheet is a polyester spun bonded non-woven fabric.

Claim 9

The printing blanket of claim 1 in which a. the void-free printing layer is 4-6 mils in thickness of an elastomeric material of an acrylonitrile/butadiene copolymer having a Shore A hardness of 30-60 durometer; b. the polyester film is a polyethylene terephthalate film and 3-5 mils in thickness; c. the soft highly resilient void-free rubber backing is an epichlorohydrin rubber having a thickness of 20-40 mils; d. a fibrous backing sheet of a spun bonded polyester non-woven fabric.

Claim 10

An offset printing blanket consisting essentially of a. 4-6 mils of a void-free printing layer of an elastomeric material of an acrylonitrile/butadiene copolymer having a Shore A hardness of 30-60 durometer firmly adhered to b. a polyethylene terephthalate film about 2-6 mils in thickness having a tensile strength of 20,000 to 180,000 pounds per square inch and firmly adhered to c. a soft highly resilient void-free rubber backing layer of an epichlorohydrin rubber laving a thickness of 20-40 mils; and d. a pressure sensitive adhesive backing firmly adhered to the rubber backing layer; wherein the blanket has a modulus of elasticity of 1 to 4 X 10 7 dynes per centimeter and a Bayshore Resiliance of 30-50 percent measured according to ASTM-D-2632-67 and a permanent set of 1-3 percent measured according to ASTM-395-61 Method A.

Claim 11

An offset printing blanket consisting essentially of a. 4-6 mils of a void-free printing layer of an elastomeric material of an acrylonitrile/butadiene copolymer having a Shore A hardness of 30-60 durometer firmly adhered to b. a polyethylene terephthalate film about 2-6 mils in thickness having a tensile strength of 20,000 to 180,000 pounds per square inch and firmly adhered to c. a soft highly resilient void-free rubber backing layer of an epichlorohydrin rubber laving a thickness of 20-40 mils; and d. a pressure sensitive adhesive backing firmly adhered to the rubber backing layer; wherein the blanket has a modulus of elasticity of 1 to 4 X 10 7 dynes per centimeter and a Bayshore Resiliance of 30-50 percent measured according to ASTM-D-2632-67 and a permanent set of 1-3 percent measured according to ASTM-395-61 Method A.

Claim 12

A process for preparing a printing blanket which comprises: a. pReparing a laminate by coating a polyester film being 3-6 mils in thickness and having a tensile strength of 20,000 to 180,000 pounds per square inch on both sides with a primer composition and calendaring on one side of the primed polyester film 3-10 mils of elastomeric material having a Shore A hardness of 30-60 durometer; b. preparing a second laminate by coating a fibrous backing material with a cement composition and calendaring onto the cement coated fabric 20 to 65 mils of a highly resilient void-free rubber backing layer; and c. laminating the layers prepared in steps (a) and (b) above together at 15 to 100 pounds per square inch for about 2 to 20 minutes to about 125*-250*C. to form a printing blanket which has an elastomeric top layer, polyester film inner layer firmly adhered to the resilient void-free rubber backing layer that is in firm adherence to the fibrous backing sheet.

Claim 13

A process for preparing a printing blanket which comprises: a. pReparing a laminate by coating a polyester film being 3-6 mils in thickness and having a tensile strength of 20,000 to 180,000 pounds per square inch on both sides with a primer composition and calendaring on one side of the primed polyester film 3-10 mils of elastomeric material having a Shore A hardness of 30-60 durometer; b. preparing a second laminate by coating a fibrous backing material with a cement composition and calendaring onto the cement coated fabric 20 to 65 mils of a highly resilient void-free rubber backing layer; and c. laminating the layers prepared in steps (a) and (b) above together at 15 to 100 pounds per square inch for about 2 to 20 minutes to about 125*-250*C. to form a printing blanket which has an elastomeric top layer, polyester film inner layer firmly adhered to the resilient void-free rubber backing layer that is in firm adherence to the fibrous backing sheet.

Claim 14

The process of claim 10 in which the polyester film is a polyethylene terephthalate film; the elastomeric material is an acrylonitrile/butadiene copolymer; the rubber backing layer is an epichlorohydrin rubber; and the fibrous backing material is a non-woven spun bonded polyester fabric.