Thermal transfer image receiving sheet and method

Abstract

A thermal transfer image-receiving polymeric sheet capable of recording thereon thermally transferred dye or ink images in a clear and sharp form. The image-receiving layer comprises at least one water dispersible aliphatic polyether-polyurethane resin and at least one water dispersible aliphatic polyester-polyurethane resin or a silica dispersion or an anionic aqueous emulsion of wax.

1 . A thermal transfer image receiving sheet comprising: 
 a substrate sheet supporting an image receiving resinous layer for receiving a transferred image, wherein the image receiving layer is formed by drying an aqueous coating composition,    the aqueous coating composition comprising (a) at least one water dispersible aliphatic polyether-polyurethane resin, and at least one water dispersible aliphatic polyester-polyurethane resin, or (b) at least one water dispersible aliphatic polyether-polyurethane resin, a silica dispersion, and an anionic aqueous emulsion of wax; and an aqueous crosslinking agent.    
   
   
       2 . The thermal transfer image receiving sheet of  claim 1  wherein the substrate sheet comprises polyester.  
   
   
       3 . The thermal transfer image receiving sheet of  claim 2  wherein the substrate sheet comprises polyethylene terephthalate.  
   
   
       4 . The thermal transfer image receiving sheet of  claim 1  wherein the polyether-polyurethane resin comprises the reaction product of an aliphatic polyisocyanate component and a polyether polyol component.  
   
   
       5 . The thermal transfer image receiving sheet of  claim 1  wherein the polyester-polyurethane resin comprises the reaction product of an aliphatic polyisocyanate component and a polyester polyol component.  
   
   
       6 . The thermal transfer image receiving sheet of  claim 1  wherein the image receiving resinous layer has a thickness in a range of from about 1 micrometers to about 50 micrometers.  
   
   
       7 . A dye receiving coating composition comprising: 
 an aqueous dispersion of at least one water dispersible aliphatic polyether-polyurethane resin;    a silica dispersion; and    an anionic aqueous emulsion of wax.    
   
   
       8 . The dye receiving coating composition of  claim 7  further comprising a multifunctional crosslinking agent.  
   
   
       9 . The dye receiving coating composition of  claim 8  wherein the multifunctional crosslinking agent comprises a polyfunctional aziridine.  
   
   
       10 . The dye receiving coating composition of  claim 8  wherein the coating composition is substantially free of organic solvent.  
   
   
       11 . The dye receiving coating composition of  claim 7  wherein the anionic aqueous emulsion of wax comprises 2-diethylaminoethanol.  
   
   
       12 . The dye receiving coating composition of  claim 7  wherein the aliphatic polyether polyurethane comprises the reaction product of an aliphatic polyisocyanate component and a polyether polyol component.  
   
   
       13 . A method of forming a thermal transfer image receiving sheet, comprising: 
 coating a substrate sheet surface with an aqueous coating composition, the aqueous coating composition comprising (a) at least one water dispersible aliphatic polyether-polyurethane resin, at least one water dispersible aliphatic polyester-polyurethane resin, and an aqueous crosslinking agent; or (b) an aqueous dispersion of at least one water dispersible aliphatic polyether-polyurethane resin, a silica dispersion, and an anionic aqueous emulsion of wax, and an aqueous crosslinking agent; and    drying the aqueous coating composition, and thereby to form the thermal transfer image receiving sheet.