Polyester, namely polyester fiber, is a kind of chemical synthetic fiber. As an important variety of textile fiber, polyester fiber is widely used in clothing fabrics and industrial products.
Because of its excellent formability, the flat, fluffy or pleated shape of polyester yarn or polyester fabric can remain unchanged even after being washed for many times.
Disperse dyes and heat transfer printing are commonly used in polyester fabric printing.
Disperse dyes can be classified into low temperature type (E type), high temperature type (s type) and medium temperature type (SE type). Disperse dyes are required to have certain sublimation fastness for pure polyester fabric printing.
The dyes with low sublimation fastness will stain the white ground when they are hot-melt fixation, and the dyes with low fixation rate will stain the white ground when they are washed by post-treatment water. Therefore, medium temperature (SE) and high temperature (s) dyes are mostly used for high-temperature hot-melt fixation in polyester fabric printing.
"Heat transfer printing"
Transfer printing is a printing method in which disperse dyes or coatings are printed on paper according to pattern pattern to make transfer paper, and then the dyes or coatings on transfer paper are transferred to textiles under certain conditions.
Theoretically, there are four methods for transfer printing: melt transfer, stripping transfer, semi wet transfer and gas phase transfer. Among them, the most commonly used method for polyester fabric is vapor transfer, also known as sublimation heat transfer, or heat transfer for short.
The disperse dyes on transfer paper are volatile and have great affinity for polyester fabric. In the process of contact hot pressing, the dyes on paper are transferred to the fabric through gasification sublimation heat transfer.
Heat transfer printing is especially suitable for printing small batches of varieties. It does not need post-treatment after printing, reducing pollution and belongs to clean processing. The patterns printed by heat transfer printing are rich and colorful, rich in layers, strong in pattern performance and few in printing defects. It is suitable for printing photographic patterns and geometric patterns with lifelike patterns and high artistry.
"Requirements for heat transfer printing of polyester fabrics"
Generally, there is no pretreatment equipment in the transfer printing factory, so the polyester fabric should be machine washed, bleached (dyed), set and soft before printing.
Only light colored fabrics such as bleached and natural white can be used for printing bottom cloth, and light colored patterns cannot be printed with dark fabrics.
The temperature of heat transfer printing is generally in the range of 150-200 ℃. Due to the high temperature, all kinds of coating of the fabric will be damaged, so when it needs to be processed again, it is generally printing first, then coating, composite and other finishing processes.
In the process of heat transfer printing, different fabrics will have different shrinkage under high temperature, generally considering the shrinkage of 2-3%. For printed fabrics with high requirements for door panel or pattern positioning, the merchandiser should pay special attention to the finalization of the dyeing plant.
In heat transfer printing, the effect of fabric printing will be different with different transfer paper and ink.
The quality of printing paper affects the effect of pattern. Transfer paper with poor quality has more color spots and pulp spots, which is easy to produce color spots; transfer paper with good quality is all wood pulp paper, which has no color spots and white spots after fabric printing.
Ink determines the color fastness of printed fabric.
When printing proofing, digital proofing is just for the convenience of confirmation of pattern, and there will be some differences with bulk samples. The transfer printing of polyester fabric is finally based on the standard of the large goods in the printing factory.