Static dissipative polyurethane foams

Abstract

A static dissipative flexible polyurethane foam is formed under free rise expansion conditions from a polyether graft polyol, a polyether polyol or ester polyol and an isocyanate, wherein one or more anti-static additives are incorporated into the reaction mix in an amount from 0.10 to 20 parts by weight. Water is added in an amount of from 0.2 to 1.0 parts per weight. Upon curing, the foam has a density in the range of 6 to 20 pounds per cubic foot, a surface resistivity below 1 x 10 11 ohms/square, and a pore size in the range of 100 to 250 pores per inch. The foam may be fabricated (cut or shaped) to form a shaped article, such as a roller, a clean room wipe, a cosmetic applicator or a packaging element.

1 . A roll for use in an image-forming apparatus comprising a polymeric foam wherein the foam exhibits a density of at least about 6 pounds per cubic foot and a compression force deflection of at least about 2.5 pounds per square inch.  
     
     
         2 . The roll as recited in  claim 1  wherein the polymeric foam comprises an open-celled, non-reticulated polymeric foam.  
     
     
         3 . The roll as recited in  claim 1  wherein the polymeric foam comprises either a polyether based or polyester based polyurethane.  
     
     
         4 . The roll as recited in  claim 1  wherein the density is from about 6.0 to about 10 pounds per cubic foot, and the compression force deflection is from about 2.5 to about 5.7 pounds per square inch.  
     
     
         5 . The roll as recited in  claim 1  wherein the density is from about 7.0 to about 8.9 pounds per cubic foot, and the compression force deflection is from about 2.5 to about 4.7 pounds per square inch.  
     
     
         6 . The roll as recited in  claim 1  wherein the density is about 8.9 pounds per cubic foot, and the compression force deflection is about 4.6 pounds per square inch.  
     
     
         7 . The roll as recited in  claim 1  wherein the foam is cylindrically disposed about a core shaft, and is substantially homogeneous.  
     
     
         8 . The roll as recited in  claim 7  wherein the foam forms the outer surface of the roll.  
     
     
         9 . The roll as recited in  claim 7  wherein the core shaft is metallic.  
     
     
         10 . The roll as recited in  claim 1  comprising at least one agent substantially uniformly dispersed throughout the foam.  
     
     
         11 . The roll as recited in  claim 10  wherein the at least one agent comprises a conductive agent.  
     
     
         12 . The roll as recited in  claim 11  wherein the conductive agent comprises a hexahalogentated ionic compound.  
     
     
         13 . The roll as recited in  claim 12  wherein the hexahalogenated ionic compound is selected from the group consisting of potassium hexafluorophosphate, sodium hexafluorophosphate, and ammonium hexafluorophosphate.  
     
     
         14 . The roll as recited in  claim 13  wherein the hexahalogenated ionic compound is potassium hexafluorophosphate.  
     
     
         15 . The roll as recited in  claim 1  wherein the foam exhibits an average linear cell count of from about 90 to about 120 pores per inch.  
     
     
         16 . The roll as recited in  claim 1  wherein the foam exhibits an electrical resistivity of less than about 1×10 9  ohm-cm.  
     
     
         17 . An image-forming apparatus comprising a roll as recited in  claim 1 .  
     
     
         18 . A toner adder roll for use in an electrophotographic image-forming apparatus comprising a substantially homogeneous layer of open-celled, non-reticulated polyurethane foam cylindrically disposed about a metal shaft, further comprising at least one conductive agent dispersed substantially uniformly throughout the foam, and wherein the foam exhibits a density of at least about 6.0 pounds per cubic foot, a compression force deflection of at least about 2.5 pounds per square inch, and average linear cell count of from about 90 to about 120 pores per inch, and a resistivity of less than about 1×10 9  ohm-cm.  
     
     
         19 . An electrophotographic image-forming apparatus comprising a roll as recited in  claim 18 .  
     
     
         20 . A method for applying toner to a developing member in an electrophotographic image-forming apparatus, comprising applying the toner via a roll comprising a polymeric foam wherein the foam exhibits a density of at least about 6.0 pounds per cubic foot and a compression force deflection of at least about 2.5 pounds per square inch.  
     
     
         21 . The method as recited in  claim 20  wherein the polymeric foam comprises an open-celled, non-reticulated polymeric foam.  
     
     
         22 . The method as recited in  claim 20  wherein the polymeric foam comprises either a polyether based or polyester based polyurethane.  
     
     
         23 . The method as recited in  claim 20  wherein the roll comprises at least one conductive agent substantially uniformly dispersed throughout the foam.  
     
     
         24 . The method as recited in  claim 20  wherein the foam exhibits an average of from about 90 to about 110 pores per inch.  
     
     
         25 . The method as recited in  claim 20  wherein the roll exhibits a resistivity of less than about 1×10 9  ohm-cm.