PRINTING BLANKET OR SLEEVE INCLUDING THERMOPLASTIC POLYURETHANE OR THERMOPLASTIC POLYURETHANE ALLOY LAYERS
An image transfer product such as a printing blanket or sleeve is provided which includes at least a base layer, a printing surface layer, and an optional intermediate compressible layer, where one or more of the layers is formed from a thermoplastic polyurethane or thermoplastic polyurethane alloy. The thermoplastic polyurethane compressible layer has a plurality of voids therein introduced by the use of pre-expanded or unexpanded microspheres. The resulting blanket or sleeve exhibits good resistance to compression.
1 . A printing blanket or sleeve comprising:
a base layer;
a compressible layer comprising a thermoplastic polyurethane or a thermoplastic polyurethane alloy, said compressible layer having voids therein; and
a printing surface layer.
2 . The blanket or sleeve of claim 1 wherein said thermoplastic polyurethane comprises a polyester-based polyurethane.
3 . The blanket or sleeve of claim 1 wherein said compressible layer comprises an alloy of a thermoplastic polyurethane with a material selected from nitrile rubber, EPDM, polysulfide, and butyl rubber.
4 . The blanket or sleeve of claim 1 wherein said base layer comprises a fabric, metal, or a polymeric material.
5 . The blanket or sleeve of claim 1 wherein said base layer comprises a thermoplastic polyurethane or thermoplastic polyurethane alloy.
6 . The blanket or sleeve of claim 1 wherein said printing surface layer comprises a rubber or polymeric material.
7 . The blanket or sleeve of claim 1 wherein said printing surface layer comprises a thermoplastic polyurethane or thermoplastic polyurethane alloy.
8 . A printing blanket or sleeve comprising:
a base layer comprising a thermoplastic polyurethane or thermoplastic polyurethane alloy; and
a printing surface layer comprising a thermoplastic polyurethane or thermoplastic polyurethane alloy.
9 . The printing blanket or sleeve of claim 8 further including a compressible layer positioned between said base layer and said printing surface layer comprising a thermoplastic polyurethane or a thermoplastic polyurethane alloy, said compressible layer having voids therein.
10 . The printing blanket or sleeve of claim 8 wherein said printing surface layer comprises a thermoplastic polyurethane alloy.
11 . The printing blanket or sleeve of claim 10 wherein said printing surface layer comprises an alloy of thermoplastic polyurethane with a material selected from nitrile rubber, EPDM, polysulfide and butyl rubber.
12 . The printing blanket or sleeve of claim 8 further including an image reinforcement layer positioned below said printing surface layer comprising a fabric, a thermoplastic polyurethane, or a thermoplastic polyurethane alloy.
13 . The printing blanket or sleeve of claim 12 wherein said image reinforcement layer comprises a thermoplastic polyurethane having a Shore A hardness which is greater than the Shore A hardness of said printing surface layer.
14 . The printing blanket or sleeve of claim 13 wherein said image reinforcement layer has a Shore A hardness of between about 70 to 95.
15 . The printing blanket or sleeve of claim 8 further including a reinforcing fabric layer positioned below said printing surface layer.
16 . A method of making a printing blanket or sleeve including a compressible layer comprising:
providing a base substrate web or sleeve;
providing a source of thermoplastic polyurethane or thermoplastic polyurethane alloy in liquid form including a void-producing material;
extruding said thermoplastic polyurethane or thermoplastic polyurethane alloy over substantially the entire surface of said base substrate or sleeve to form a compressible layer thereon; and
providing a printing surface layer over said compressible layer.
17 . The method of claim 16 wherein said void-producing material is selected from the group consisting of pre-expanded microspheres, unexpanded microspheres, blowing agents, and leachable additives.
18 . The method of claim 17 wherein said void-producing material comprises unexpanded microspheres and wherein extruding said thermoplastic polyurethane or thermoplastic polyurethane alloy further comprises expanding said microspheres.
19 . The method of claim 17 wherein said void-producing material comprises unexpanded microspheres and wherein said microspheres are expanded by heating after extrusion of said compressible layer.
20 . A method of making a printing blanket or sleeve including a compressible layer comprising:
providing a base layer comprising a substrate web or sleeve;
applying a compressible layer comprising a thermoplastic polyurethane or thermoplastic polyurethane alloy to said substrate web or sleeve; said compressible layer including voids therein; and
providing a printing surface layer over said compressible layer.
21 . The method of claim 20 wherein said compressible layer is laminated to said base layer.
22 . The method of claim 20 wherein said base layer comprises a fabric, metal, polymer, or a thermoplastic polyurethane or thermoplastic polyurethane alloy.
23 . The method of claim 20 wherein said printing surface layer comprises a rubber, polymer, or thermoplastic polyurethane or thermoplastic polyurethane alloy.
24 . The method of claim 20 further including providing an image reinforcement layer between said compressible layer and said printing surface layer.
25 . A method of making a printing blanket or sleeve comprising:
providing a base layer comprising a substrate web or sleeve; said base layer comprising a thermoplastic polyurethane or thermoplastic polyurethane alloy; and
providing a printing surface layer over said base layer; said printing surface layer comprising a thermoplastic polyurethane or thermoplastic polyurethane alloy.