Transfer printing sheet with impregnating agents and two-component electrophotographic toner and transfer printing of textile materials of cotton

Claim 1

In a process for the preparation of a transfer printing support in sheet or web form for the thermoprinting of hydroxyl group or nitrogen containing textile fiber materials, comprising the steps of: (a) providing an electrophotographic toner of the two-component type by blending finely divided toner particles having a particle size of from 5 to 20 micrometers containing at least one dyestuff and a polymeric binder, with a particulate carrier, the carrier particles being coarser than the toner particles, (b) providing a latent electrostatic image on a photoconductor surface by electrophotography, (c) developing said latent electrostatic image of step (b) by means of the toner of step (a), (d) transferring said developed image of step (c) onto a flat flexible transfer printing substrate, and (e) fixing said transferred image obtained in step (d) on said transfer printing substrate by at least one means selected from heat and pressure, the improvements comprising: (1) using dyestuff in step (a) which is not substantially water soluble at leasat at neutral pH, which doess not visibly sublime under the conditions of sublimation transfer printing and which is capable of thermosoling, (2) using in step (d) a flat flexible transfer printing substrate which has been coated with a mixture of at least one impregnating agent which is a non-toxic organic substance containing at least one nitrogen atom in its molecule, which is solid up to 60° C. and has a melting temperature in the range from 60° C. to 230° C., which is liquid up to at least 230° C. and substantially colorless, and which is not a film-forming polymer wherein the impregnating agent is selected from the group consisting of caprolactam, nicotinic amide, isonicotinic amide, propylene urea, ethylene urea, glyoxal monurein, urea, 5,5-dimethyl hydantoin, imidazol, 2-methyl imidazol, N-methyl pyrrolidone, N-hydroxy succinimide, biuret, dimethylol urea, dimethylol hydroxyethylene urea, dimethylol ethylene urea, and mixtures thereof; and a polymeric binder, (3) said dyestuff of step (1) and said impregnating agent of step (2) being selected such that the impregnating agent in its liquid state but not in its solid state has solvent properties for said dyestuff.