Requirements for dyes and color inks in transfer printing

For disperse dyes used in transfer printing, the sublimation temperature should be lower than the melting point of the fiber macromolecules and not damage the fabric strength. The suitable processing temperature for polyester is 180-210 °C. In this temperature range, the sublimation of dyes has a molecular weight between 230 and 270. There are generally three types of disperse dyes with molecular weights in this range.

Fast-dyeing disperses dyes: the temperature can be sublimated at about 180 ° C, and the color will change when the temperature is raised, and the edges will seep.

Good disperse dyes: the temperature can be sublimated to the range of 180～210℃.  The hair color curve is flat. The temperature has little effect on dyeing, and it is a suitable disperse dye for transfer printing.

 Delayed dyeing disperses dyes: dyes cannot sublime well and develop color at 180～210℃. If the temperature is increased, a good color can be obtained. Such dyes are highly temperature-dependent when dyed.

According to the above situation, the dyes suitable for transfer printing should meet the following conditions:

(1) The dyes for transfer printing must be fully sublimated and fixed on the fibers below 210°C, and good washing fastness and ironing fastness can be obtained.

(2) The dyes of transfer printing can be fully sublimated and transformed into gas-phase dye macromolecules after being heated, condensed on the surface of the fabric, and can diffuse into the fiber.

(3) The dye used for transfer printing has a small affinity for the transfer paper and a large affinity for the fabric.

(4) The dyes for transfer printing should have bright and bright colors.

Color ink for transfer printing paper

(1) Coloring agent

The function of the vehicle is to evenly distribute the dye in the color ink and transfer the dye from the printing equipment to the transfer paper. The vehicle should be inexpensive, non-toxic and non-flammable. According to this requirement, water is the most suitable. However, the transfer paper is made of cellulose.. When water is used as the vehicle, the fibers will expand, resulting in the deformation of fine patterns, and it is difficult to produce at high speed due to the slow evaporation of water. If the organic solvent vehicle is used, although the deformation of the paper is small, the color ink can print fine patterns and has a suitable volatility, which is conducive to the advantages of high-speed production. However, it has the disadvantages of high cost and easy combustion. Be careful with it.. Oil vehicles such as high boiling point oils can also be used. But high-boiling oils can diffuse the dye deep into the transfer paper, affecting the amount of dye on the transfer paper that is transferred to the fabric.

(2) Binder

Binder refers to the substance that controls the adhesion of color ink. If the amount of binder is too small, the viscosity of the ink cannot be guaranteed, resulting in poor printing effect of the transfer paper. If the amount of the binder is too large, the transfer speed of the dye from the transfer paper to the fabric will be slowed down, which will cause residues in the transfer paper. Too much dye on the paper. Depending on the vehicle used, the binder should be selected separately. When water is used as the vehicle, commonly used synthetic dragon gum or carboxymethyl cellulose is used as the binder: when using organic solvents or oils as the vehicle, ethyl cellulose can be used as the binder.

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