Heat transfer materials and methods of making and using the same
View Patent ↗A heat transfer paper configured to reduce the amount of stray toner on a heat transfer material, especially when the image is formed via a laser printer or laser copier, is generally disclosed. The heat transfer material includes an image-receptive coating overlying a splittable layer and a base sheet. The image-receptive coating includes thermoplastic polyolefin wax microparticles, a thermoplastic binder, and a humectant. The thermoplastic polyolefin wax microparticles have an average particle size of from about 30 microns to about 50 microns and melt at temperatures between about 130° C. and about 200° C.
1. A heat transfer material configured for hot peel heat transfer of an image to a substrate, the heat transfer material comprising:
a base sheet;
a splittable layer overlying the base sheet; and
an image-receptive coating overlying the splittable layer; wherein the image image-receptive coating comprises thermoplastic polyolefin wax microparticles, a thermoplastic binder, and a humectant, wherein the thermoplastic polyolefin wax microparticles have an average particle size of from about 30 microns to about 50 microns and melt at temperatures between about 130° C. and about 200° C., and wherein the humectant is configured to draw moisture back into the heat transfer material after drying.
2. A heat transfer material as in claim 1 , wherein the thermoplastic polyolefin wax microparticles comprise a thermoplastic polyolefin wax polymer having a weight average molecular weight of about 10,000 to about 15,000.
3. A heat transfer material as in claim 1 , wherein the humectant comprises urea.
4. A heat transfer material as in claim 3 , wherein the ink image-receptive coating further comprises a second humectant.
5. A heat transfer material as in claim 4 , wherein the second humectant comprises a hydrophilic polymer.
6. A heat transfer material as in claim 5 , wherein the hydrophilic polymer comprises polyethylene glycol or polypropylene glycol.
7. A heat transfer material as in claim 5 , wherein the hydrophilic polymer is included in an amount of about 0.01% to about 2% by weight based on the dry weight of the image-receptive coating.
8. A heat transfer material as in claim 1 , wherein the thermoplastic polyolefin wax microparticles comprise polypropylene.
9. A heat transfer material as in claim 1 , wherein the thermoplastic polyolefin wax microparticles melt at temperatures between about 150° C. and about 175° C.
10. A heat transfer material as in claim 1 , wherein the thermoplastic polyolefin wax microparticles have an average particle size of from about 35 microns to about 45 microns.
11. A heat transfer material as in claim 1 , wherein the image-receptive coating further comprises a plurality of second thermoplastic polymer microparticles having an average particle size of from about 2 microns to about 50 microns.
12. A heat transfer material as in claim 11 , wherein the image-receptive coating comprises the thermoplastic polyolefin wax microparticles in an amount from about 10% to about 75% by weight based on the dry weight of the image-receptive coating, and wherein the image-receptive coating comprises the second thermoplastic polymer microparticles in an amount from about 10% to about 75% by weight based on the dry weight of the image-receptive coating.
13. A heat transfer material as in claim 1 , wherein the image-receptive coating comprises the thermoplastic binder from about 5% to about 40% by weight based on the dry weight of the image-receptive coating.
14. A heat transfer material as in claim 1 , wherein the image-receptive coating is substantially free from a cross-linking agent.
15. A heat transfer material as in claim 1 , wherein the splittable layer directly overlies the base sheet, and wherein the image-receptive coating directly overlies the splittable layer.
16. A heat transfer material as in claim 1 , wherein the splittable layer comprises a polymeric material that melts at temperatures between 80° C. and 130° C.
17. A heat transfer material as in claim 1 , wherein the splittable layer comprises a polymer having a melt index of at least about 25 g/10 minutes.
18. A heat transfer material as in claim 1 , wherein the splittable layer comprises a combination of ethylene-methacrylic acid copolymer and ethylene-acrylic acid copolymer.
19. A heat transfer material as in claim 1 , wherein the splittable layer is an extruded film layer.
20. A heat transfer material as in claim 1 , wherein the ink image-receptive coating comprises the thermoplastic polyolefin wax microparticles in the amount of about 25% to about 50% by weight based on the dry weight of the ink image-receptive coating.
21. A heat transfer material as in claim 1 , wherein the ink image-receptive coating comprises the thermoplastic polyolefin wax microparticles in the amount of about 30% to about 45% by weight based on the dry weight of the ink image-receptive coating.
22. A method of transferring an image to a substrate using the heat transfer material of claim 1 , the method comprising:
printing toner ink onto the image-receptive coating of the heat transfer material of claim 1 to form an image;
positioning the heat transfer material adjacent the substrate, wherein the image-receptive coating contacts the substrate;
heating the heat transfer material to a temperature of about 150° C. to about 300° C.; and
peeling the base sheet from the substrate while the heat transfer material is still warm.