Sublimation printing of heat sensitive materials
The present invention further relates a sublimation printing process of a multilayer system comprising a polyester top layer and at least one heat sensitive polymer layer whereby a temperature gradient is applied during sublimation printing such that the heat sensitive polymer layer is maintained at a temperature below its melting temperature and the polyester top layer is maintained at a temperature above its glass transition temperature to allow diffusion of a sublimation dye into the polyester top layer. The temperature gradient is maintained by using a heat sink element beneath the heat sensitive polymer layer. The temperature gradient can also be maintained by cooling the heat sink element. The cooling preferably occurs with a circulating coolant. The heat sink element comprises a polymer, a ceramic or a metal. The invention further relates to a sublimation printed multilayer system comprising a polyester top layer and at least one heat sensitive polymer layer. The present invention also relates to the multilayer system in the manufacturing of textile, tents, outdoor gear, apparel, clothing, bags, jackets, gloves.
1. A dye sublimation printing process comprising the steps of:
(i) providing a multilayer system comprising a polyester top layer and at least one heat sensitive polymer layer comprising a polymer with a melting point below sublimation temperature,
(ii) subjecting the multilayer system to dye sublimation printing by application of a sublimation dye to the polyester top layer of the multilayer system, and
(ii) applying a temperature gradient to the multilayer system during the dye sublimation printing according to step (ii) such that the heat sensitive polymer layer is maintained at a temperature below a melting temperature thereof and the polyester top layer is maintained at a temperature above a glass transition temperature thereof to allow diffusion of the sublimation dye into the polyester top layer.
2. The dye sublimation printing process according to claim 1 , wherein step (iii) comprises maintaining the temperature gradient by using a heat sink element beneath the heat sensitive polymer layer.
3. The dye sublimation printing process according to claim 2 , wherein step (iii) comprises maintaining the temperature gradient by cooling the heat sink element beneath the heat sensitive polymer layer.
4. The dye sublimation printing process according to claim 3 , wherein step (iii) comprises circulating a coolant to effect cooling of the heat sink element.
5. The dye sublimation printing process according to claim 2 , wherein the heat sink element comprises a polymer, a ceramic or a metal.
6. The dye sublimation printing process according to claim 5 , wherein the heat sink element comprises a metal.
7. The dye sublimation printing process according to claim 1 , wherein the polyester top layer comprises polyethylene terephthalate (PET) or polybutylene terephthalate (PBT).
8. The dye sublimation printing process according to claim 1 , wherein the sublimation dye has a sublimation temperature of at least 190° C., and wherein the heat sensitive polymer comprises a polymer with a melting temperature below the sublimation temperature of the sublimation dye.
9. The dye sublimation printing process according to claim 1 , wherein the heat sensitive polymer is selected from the group consisting of polyolefins, polyamides, polyester block copolymers and polyurethanes.
10. The dye sublimation printing process according to claim 9 , wherein the heat sensitive polymer is polyethylene.
11. The dye sublimation printing process according to claim 10 , wherein the heat sensitive polymer is ultrahigh molecular weight polyethylene (UHMWPE).
12. The dye sublimation printing process according to claim 1 , wherein the multilayer system is in the form of a multilayer film, a laminate, a knitted fabric, a woven fabric, a non-woven structure, a felt structure, a composite structure and/or combinations thereof.
13. The dye sublimation printing process according to claim 12 , wherein the multilayer system is in the form of a fabric comprising a double face woven or knitted structure.
14. The dye sublimation printing process according to claim 12 , wherein the multilayer system is in the form of a laminate structure further comprising a waterproof breathable membrane.
15. The dye sublimation printing process according to claim 14 , wherein the waterproof breathable membrane comprises polytetrafluoroethylene (PTFE), polyurethane or a block copolyester.
16. The dye sublimation printing process according to claim 12 , wherein the multilayer system is in the form of a composite comprising at least first and second unidirectional layers, wherein the first unidirectional layer comprises high-performance fibers, aligned in a parallel direction in a first matrix material, and the second unidirectional layer comprises high performance fibers, aligned in a parallel direction in a second matrix material.
17. The dye sublimation Sublimation-printing process according to claim 16 , wherein the second fiber direction is offset relative to the first fiber direction by up to 90 degrees.
18. The dye sublimation printing process according to claim 16 , wherein the high performance fibers in the first and second unidirectional layers are ultrahigh molecular weight polyethylene (UHMWPE) fibers which are the same or different.
19. The dye sublimation printing process according to claim 16 , wherein the first and second matrix materials are the same or different and are selected from the group consisting of polyacrylates, polyurethanes, polyesters, silicones, polyolefins, and polyamides.
20. The dye sublimation printing process according to claim 19 , wherein the first and second matrix materials are modified polyolefins, ethylene copolymers or polypropylene.
21. The dye sublimation printing process according to claim 1 , wherein step (ii) comprises directly printing an image onto the polyester top surface of the multilayer system with the sublimation dye.
22. The dye sublimation printing process according to claim 1 , wherein step (ii) comprises positioning a transfer substrate having an image formed of the sublimation dye to be transferred to the multilayer system on the polyester top layer of the multilayer system.
23. A printed multilayer system obtained by the process according to claim 1 .