What role does paper play in the production of fabric?
There are many different options available for printing textiles: flex and flock transfer printing, screen printing, digital direct printing and digital sublimation printing. Each printing process has its benefits. However, when full colour designs are getting truly complex, digital transfer printing, or dye sublimation printing, is the most effective method of achieving permanent prints on polyester-based textiles.
Sublimation printing transfers the dyes onto the fabric at a molecular level, essentially meaning the ink is absorbed and fixed within the yarns, rather than the dye sitting on the fabric to simply wash off. This process results in a completely permanent, incredibly vibrant printed synthetic fabric.
It all starts with paper
The sublimation process begins with paper, upon which the required image is digitally printed, using water-based sublimation inks. In a second step, the so called transfer paper is placed onto the synthetic fabric of choice and in the transfer press or calender, heat and pressure are applied during a defined time. By doing so, the image adheres permanently to the fabric.
Sappi’s high quality digital sublimation transfer papers ensure reproducible colour results on various polyester based surfaces. Our Transjet brand has become a generic term for dye sublimation papers worldwide.
How does the paper make a difference?
Each transfer paper of our portfolio is different due to its composition, structure, coating and grammage. So each paper absorbs, dries and releases the ink in its own specific way dedicated to various processes and applications. The composition, the thickness and the type of structure of the substrate will influence the results. An accurate selection of both paper and substrate is crucial.
The final grammage and type of coating of the paper must be considered. Dye sublimation papers can be found at about 20g/m² for Basejet uncoated papers and can reach, in the Sappi Transjet coated dye sublimation paper range, a maximum grammage of 130g/m². Depending on the customer process, the final application and the kind of substrate to which the image will be transferred, the specific paper and grammage need to be carefully chosen. The combination of grammage and coating of the papers affects not only the ink-load but the complete process, from printing to transfer.
Ink absorption is a particularly important characteristic of the transfer paper as it determines both printing and transferring processes. For a given paper, the absorption of the ink depends on the transfer paper’s drying capacity, the type and amount of ink used, the type of printer (e.g. its printheads, drying capacity and speed) and, last but not least, the environmental conditions as humidity and temperature can have a significant influence on the drying behavior of the paper. The faster the ink dries, the quicker the printing process can be. The printed surface must be completely dry before winding on the previous layers of papers of the roll, otherwise a setoff issue may occur and the quality of the prints will be negatively impacted.
Once the print is perfectly dry, the transferring process can be done. If the printed paper remains protected from humid environment while stocked, it maintains its properties and may guarantee excellent transferring results even after several days.
If you want to find out which paper suits your requirements best, do not hesitate to get in touch with us! We help you achieve the results you are aiming for.