Media used for transferring an image on a bi-dimensional or tri-dimensional article by a thermal transfer printing process and process for making such media
An Ink transfer medium configured to receive and transfer an image on a bi-dimensional or tri-dimensional article by way of thermal transfer. The ink transfer medium includes a sub-layer made of amorphous polyethylene terephthalate (APET), an image receiving coating, a barrier coating, a binding system, and an ink transfer coating which includes a layer having a combination of pigment systems formed by cellulose fibers, microspheres and silica. The barrier coating includes resins and mineral elements supporting the ink transfer coating applied on the APET film.
1. An ink transfer medium configured to receive and transfer an image on a bi-dimensional or tri-dimensional article by way of thermal transfer, said ink transfer medium comprising:
a sub-layer comprising amorphous polyethylene terephthalate (APET);
a binder;
a barrier coating applied to the binder and which comprises resins and mineral elements;
an image receiving coaling applied to the barrier coating;
an ink transfer coating applied to the image receiving coating and comprising a combination of pigment systems formed by cellulose fibers and microspheres,
wherein the binder is configured to bond the barrier coating, the image receiving coating and the ink transfer coating to the APET sub-layer.
2. The ink transfer medium of claim 1 , wherein the resins comprise organic resins.
3. The ink transfer medium of claim 2 , wherein the organic resins of the barrier coating are applied in an aqueous solution with a mineral or organic pigment system.
4. The ink transfer medium of claim 2 , wherein the organic resins are formed by casein and its derivates.
5. The ink transfer medium of claim 2 , wherein the organic resins of the barrier coating are applied in solutions of 5-20% of lactic casein in water and 2-7% of ammonium hydroxide to form.
6. The ink transfer medium of claim 2 , wherein the barrier coating comprises an anhydrous coating of 1.5-5 gr/m 2 .
7. The ink transfer medium of claim 1 , wherein the ink transfer coating comprise:
cellulose fibers having a predetermined thickness and which are incorporated in a proportion of 5% to 30% of the binder; and
microspheres of methacrylate in a ratio of 0.20% to 1.00% in relationship to the binder.
8. The ink transfer medium of claim 7 , wherein the predetermined thickness is 15 micron.
9. The ink transfer medium of claim 1 , wherein the ink transfer coating further comprises silica.
10. The ink transfer medium of claim 1 , wherein the binder comprises resins chosen among polyvinyl alcohols, cellulose-based resins with plasticizers and softening agents incorporated into an aqueous alcohol or a hydro-alcohol.
11. The ink transfer medium of claim 1 , wherein the barrier coating is comprises a metalized layer.
12. A process for obtaining an ink transfer medium configured to receive and transfer an image on a bi-dimensional or tri-dimensional article by way of thermal transfer, the process comprising:
preparing a first solution comprising polyvinyl alcohol (PVA) with a concentration between 1 and 10% in water, and trichloroacetic acid (TCA) with a concentration between 3 and 20%;
providing a barrier coating by preparing under constant stirring a second solution comprising lactic casein in hot water, with a mix rate between 5% and 20%, and ammonium hydroxide between 2% and 7% to obtain a dry coating between 1.5 and 5 gr/m 2 ;
providing an ink transfer coating by preparing cellulose fibers in a proportion of 5% to 30% of a binder and having a predetermined thickness, and microspheres of methacrylate in a ratio of 0.20% to 1.00% in relationship to the binder;
pre-treating an amorphous polyethylene terephthalate (APET) sub-layer by applying the first solution on the sub-layer to obtain a wet coat weight in a range between 3 and 10 gr/m 2 , and then drying the wet coating; and
applying on the sub-layer an image receiving coating, the ink transfer coaling and the barrier coating.
13. The process of claim 12 , wherein the solution is applied using a precision application system.
14. The process of claim 13 , wherein the precision application system comprises an air knife.
15. The process of claim 13 , wherein the precision application system comprises a Meyer bar system.
16. The process of claim 13 , wherein the predetermined thickness of the cellulose fibers is 15 microns.
17. An ink transfer medium comprising:
an amorphous polyethylene terephthalate (APET) sub-layer:
a binder comprising resins chosen among polyvinyl alcohols, cellulose-based resins with plasticizers and softening agents incorporated into an aqueous alcohol or a hydro-alcohol;
an image receiving coating applied to the binder; and
an ink transfer coating applied to the image receiving coating and comprising a combination of pigment systems formed by cellulose fibers and microspheres,
wherein the binder is configured to bond the image receiving coating and the ink transfer coating to the APET sub-layer.
18. The ink transfer medium of claim 17 , wherein the ink transfer coating further comprises silica.