Epoxy curing agent emulsification for TTR application
AssigneeNCR Corporation
InventorDavid M. Dashiell
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Abstract
An aqueous coating formulation which forms a thermal transfer layer of a thermal transfer ribbon. This formulation comprises an aqueous emulsion of a thermoplastic resin and/or wax coemulsified with an epoxy curing agent. This emulsion can be combined with an aqueous dispersion of an epoxy resin. These coating formulations provide thermal transfer layers with reactive components that increase in molecular weight when heated during transfer to provide images with high scratch and smear resistance without organic solvents. The reactive components are maintained in separate phases within the same thermal transfer layer or separate thermal transfer layers until exposed to a thermal print head.
Claims36
An aqueous coating formulation which forms a thermal transfer layer of a thermal transfer medium, said thermal transfer layer having a softening point below 200° C., said coating formulation comprising:
- an aqueous emulsion of at least one thermoplastic resin and/or wax and at least one epoxy curing agent which initiates crosslinking with an epoxy resin, coemulsified with said at least one thermoplastic resin and/or wax,
- wherein said aqueous emulsion comprises an aqueous liquid which does not solubilize the epoxy curing agents, thermoplastic resins or waxes, and
- wherein the epoxy curing agents, thermoplastic resins and waxes are each solid at 20° C. and have a softening point below 200° C., the thermoplastic resins and waxes are solid at 20° C. and the epoxy curing agent is either solid at 20° C. or encapsulated in a wax or thermoplastic resin which is solid at 20° C.
An aqueous coating formulation which forms a thermal transfer layer of a thermal transfer medium, said thermal transfer layer having a softening point below 200° C., said coating formulation comprising a combination of:
- a) an aqueous emulsion of at least one thermoplastic resin and/or wax coemulsified with at least one epoxy curing agent which initiates crosslinking with an epoxy resin and
- b) an aqueous dispersion of at least one epoxy resin,
- said aqueous coating formulation comprising an aqueous liquid which does not solubilize epoxy curing agents, thermoplastic resins, waxes or the epoxy resins,
- wherein each of the epoxy resins, epoxy curing agents, thermoplastic resins and waxes have a softening point below 200° C. so as to melt mix at a temperature in the range of 50° C. to 250° C., wherein each of the epoxy resins, thermoplastic resins and waxes are solid at 20° C. and each of the epoxy curing agents are either solid at 20° C. or encapsulated in a thermoplastic resin or wax which is solid at 20° C.
A thermal transfer medium as in clam 19 wherein the second layer of the thermal transfer layer comprises from 5 to 95 wt % epoxy curing agent and from 95 to 5 weight % at least one thermoplastic resin and/or wax.
Dependencies are inferred from the claim text.