Textile screen printing technology reply

1. Why do you have the osmotic phenomenon in your own paint paste? How should you solve it?

A: Self-made paint paste is an aqueous paste for textile printing. Penetration (æ´‡) can be found from the following aspects and solve them.

1 synthetic fabric: such as polyester, nylon, polypropylene, etc., or a high proportion of synthetic fiber blends. Synthetic fiber: The fabric is a hydrophobic substance, and the water-based slurry of the printed cotton fabric is easy to seep. When printing synthetic fabrics, apply a thick emulsified paste to the paste and avoid dilution with water. If it is necessary to dilute, dilute the dilute emulsification paste and dilute it. Do not dilute it with water directly, or use the "impermeable dipping paste" produced by Tianjin.

2 Humidity in the air is too high, such as long rainy weather in the south, with little or no added water.
3 Cotton fabric is a natural cellulose fiber fabric and is a hydrophilic material. Generally not easily osmotic. However, if the capillary effect is too high, it will lead to osmosis. Therefore, the proper capillary effect is controlled at about 7 to 8 cm. It is crucial to ask the manufacturer's technical specifications before feeding. The capillary effect is too low to be impermeable, and too high to cause osmosis.

4 Some companies use emulsifying pastes as thickeners, commonly known as A to help pulp. It is emulsified by high-speed stirring with white flame oil, Pingping and Synthetic Long Jiao. If A pastes have quality problems, they are not fully emulsified, and there are “oil rings” after printing, which can easily lead to misunderstandings of “bleeding” or “watermarking”. Therefore, good quality A pulp or synthetic thickener should be used to overcome the “oil ring”.

5 There are many comprehensive factors that cause “seepage” and “squeaking”. For example, the organization of the weave is too thin, too thin, and too light; the area of ​​the pattern is too large; the mesh size is too low; the pressure during operation is too large; Patterns do not correspond, sizing is too large and so on.

In addition, the tabletop is also very much related. If the glass or plastic veneer is very smooth and rigid, it will also cause osmotic pallets. The outline is unclear, but it should be changed to a flexible soft table.

2. How to mix different color pastes?

Answer: Color science is a deeper knowledge, and color adjustment requires the accumulation of practice. First of all, from the red, yellow, blue three basic colors to try out the secondary color: orange, green, purple, and then modulated three times color: yellow gray, blue gray, red gray. Then each color in each set of color spectrum from light to medium to dark, with dosages of 0.1%, 0.5%, 1%, 3%, and 5%, respectively.

In addition, each batch of business samples and formulas should be kept for reference and perseverance.
The general principle of color mixing is as follows: First, to minimize the number of dyes or coatings used in color matching, one can be used, not two, and two can be used instead of three. In order to facilitate the control of colored light, it is generally best to use the following three color combinations. The second is similar materials or paints, different manufacturers, different brands are best not to fight together, such as must be used to "color head", then "color head" can only be minimal, not two brands equal shares. A further principle is that a dye or paint has its saturation value, exceeding its saturation value, and it is easy to wash away and cause contamination. Even if the paint is black, the amount should be controlled at 8%-10% and no more than 10%.

3. How to choose and use elastic overprinting paste to ensure its color fastness?

Answer: 1 If it is a clothing category, use a water-based elastic cover printing paste. Because the dress printing requires no odor and soft hand, especially the export of clothing or high-end products is particularly strict.

2 The type of fabric has an extremely important relationship with the color fastness of elastic overprint sizing.

Elastic overprinting sizing used for cotton fabrics should not be used on synthetic fibers. Because it can not guarantee its color fastness. Should choose polyester special or nylon special glue.

3 Rain-proof nylon or polyester, used as banner slogans, parasols, etc. The outdoor environment requires good weather fastness, should withstand the sun and rain, can be solvent-free if the odor and soft feel are not too demanding Ink, such as polyester ink, nylon ink to print. Coated fabrics should be based on the coating material is better to select the appropriate ink.

4Because the material and production process of each manufacturer are different, to understand the usage method, please read the specification carefully. Some products require drying after baking 130 ~ 150 °C, 3 ~ 5min, in order to increase color fastness. Many individual workers tend to focus on print quality and ignore post-processing processes. The process of baking is saved, resulting in a situation in which washing is eliminated and all work is abandoned. Even the low-temperature “powder” or paint paste cannot be washed after printing. It should be fully dried for 24 hours, preferably for 7 days, to achieve the highest color fastness. If it is dried at about 100°C, it will be even better if it is ironed.

Source: China Screen Printing Technology Professional Network