Thermal transfer technology (4)

b. Azo dye ink formula and application

The dark orange print dye molecular structure of the fabric is:

7.5 parts of a finely dispersed dye preparation containing the above molecular structure are prepared in a blender with 25% ethyl cellulose, and 100 parts of intaglio plate containing 90 parts of ethanol, 5 parts of acetone and 5 parts of ethyl cellulose are added. The printing emulsion was dispersed with a high speed impeller mixer for 10 minutes to obtain a stable printing ink dispersion having a Baume degree of 22. The ink was printed in a desired shape using a gravure printing machine and printed on a transfer paper, and then dried. One side of the transfer paper with a pattern printed on it is in contact with the fabric for transfer printing, resulting in a clearly defined transfer printing. The transfer process conditions were: temperature 210°C, pressure 0-100g/cm2, time 30s. The deep orange-red pattern on the fabric is characterized by resistance to sun, water, perspiration and rubbing.

In addition to anthraquinone dyes and azo dyes, commonly used anionic dyes, deep yellow dyes for polyester fiber, disperse dyes for polyacrylonitrile fiber printing, disperse dyes containing carboxylic acid groups, thermal transfer printing black dyes A and B and many more.

(2) Binder

Commonly used resins are low-viscosity ethyl cellulose, ethyl hydroxyethyl cellulose (EHEC), long oil modified alkyd resins, etc. Commonly used solvents include turpentine oil, terpineol, high boiling point alkanol, aryl alkane, and soluble fiber. Agents, etc., there are other minor additives. The main requirements for the binders are the low affinity of the dyes, the easy release of dye gases, and the appropriate printability, storage, and heat transfer adaptability.

Ink formula examples (for reference only)

Formula one:

Disperse dye 16%

Barium sulfate 16%

Ethyl cellulose 6%

Tricresyl phosphate 0.9%

Methyl isobutyl ketone 61.1%

Formula two:

Disperse dye 2%

2-ethylhexanol 10%

Special epoxy resin 2%

Water 86%

2. Base paper

The base paper for transfer printing should be selected from papers that are resistant to high temperatures, heavy pressure, and resistance to bleedout, low dye gas permeability, and high tensile strength. The surface smoothness is high so that fine patterns can be printed. The technical standards are as follows.

Absorption 40 to 100g/m2

Breathability 500 to 2000mL/min

Quantitative 50 ~ 70g/m2

pH 4.5 to 5.5

Dirt does not allow

The overseas flower paper base papers, which are made in the Netherlands, are all made of coniferous wood pulp, of which 50% are chemically loaded and 50% are mechanically loaded. Such papers do not yellow at high temperatures and are not brittle.

Sulfuric acid coniferous chemical pulp paper is also available. The paper plus filler has good high temperature resistance. The formula of the filler is as follows (for reference only).

Melamine 0.8%

Rosin 2.5%

Clay 10%

Talc powder 20%

In addition to coating paper on the base paper plus a coating, such as silicone, polyethylene acid and other substances, can increase the transfer effect.

3. Printing method

Commonly used printing methods include gravure printing, embossing printing, plain printing, and screen printing.

4. Transfer printing equipment

Generally can be divided into two types. Two kinds are: one is a batch type, generally called a lithographic type; the other is a continuous type, mainly a hot roll type. The two categories are: one is for pressurization; the other is for depressurization, that is, the so-called vacuum transfer printing with suction, the decompression transfer printing is most suitable for deformed fabrics, raised fabrics, and fabrics that are not high temperature resistant, Such as acrylic expanded fabrics, artificial fur and so on. Decompression transfer printing can also make a part of sublime disperse dyes applied, thus expanding the choice of dye surface; on the other hand, it can also increase color yield and transfer speed.