Several common problems and solutions in printing process production:
1, color migration
Colors are added to the mortar to color, some of the colors will appear color migration, dark colors migrate to the light color flower position or the colored prints migrate to the white flower position, or the color of the print goes to the unprinted fabric to call the color migration. In order to avoid the color migration during the production process, the color species must be tested for resistance to migration.
Test Method: Color (3%) + Clear Pulp (97%) – Printing – Flash Bake – Cover White Glue (100%) – Self-Dry – 130°C x 3 seconds Press. Divided into five grades with the inside eye can see the migration phenomenon is not recommended to do mortar printing, do water slurry (paint printing) printing should pay attention to white or light-colored fabric, different glue test results will be different, the difference is not too. Most of the fluorescent color is not glue migration, so it is necessary to communicate clearly with customers before production.
2, heat treatment
Most of the glue printing needs to be heat-treated, and some of the colors have poor heat resistance. After processing, serious color differences will occur, especially when mixed with thermosetting ink thick plates. Therefore, the necessary test method for the heat resistance test of color species is: 37% white glue + 60% transparent paste + 3% color is naturally dried and heat-treated at 180°C for 30 seconds, up to 5 levels. The level is 5.
3, light resistance test
At present, many companies are accepting brand companies or Europe and the United States alone, and have strict requirements for light resistance. If customers have such requirements, they may require suppliers to provide lightfastness data for paints or three-party test reports, or they may print printed samples to detect three parties. Institutional testing. The general test methods and standards are: JIS L-0842 carbon arc lamp for 20 hours.
4, solvent resistance test
At present, more and more garments are taken for dry cleaning. If the pigments have poor solvent resistance, the clothing after dry cleaning will fade and discolor, causing consumer dissatisfaction and complaints. Therefore, the clothing company will sample the goods before receiving the goods, and only after passing the goods will they receive the goods. If the customer has requested this, the supplier may be required to provide pigment lightfastness data or a third-party test report, or may print the printed sample to a third-party testing agency for testing. Test method: JISL-0860 (tetrachloroethylene, 40°C, 30 seconds).
5, pull test
It is necessary to perform pull-resistant test on the color species before drawing. Some of the pigments are not resistant to the reducing agent. When they are overheated, they completely become two colors, in order to avoid unnecessary losses. Therefore, it is necessary to test the color of the sample before it is opened. Test method: Add 5% of Rongbai powder under normal pressure at 105 °C for 8 minutes, or 170 °C for 3 minutes. Other considerations: Such as environmental performance, aromatic amines, formaldehyde, heavy metals, APEO (alkyl phenol polyvinyl chloride ether). There is also a reaction with the slurry, some of the pigment will react with the slurry, stirring thickening and thinning, gelling. Wet and wet friction and so on.
6, glue washing water off, cracking
The same cloth with different glue, the same glue with different cloths. Washability and elasticity are different. Therefore, it is necessary to test the washability of the mortar before opening the goods, conduct standard tests (national standard, American standard, European standard) according to the requirements of customers, and use the national standard washing machine and test method. Some customers do not have problems washing with household washing machines, and fail to pass the tests to a third party organization. Other customers wash by hand, and when the test is finished, OK will not work. The same person’s different environment, mood, etc., are different. Therefore, any test requires standards, different standards, different test methods, and different test results.
7, flexible test
At present, there are many kinds of textiles, and different compositions, different weaves, and different elasticities are different. A kind of pulp can not meet the elasticity of all fabrics, so it has been used to open the mortar, used in different elastic fabrics to deal with the elasticity of the mortar to re-test, and some customers do not crack after hand-pull the mortar, When the stock was finished, it was printed and finished the heat treatment. After the water washing test was completed, it was found that the printed surface was cracked. After some glues have undergone heat treatment and water washing, their elasticity and feel will change. Therefore, the elasticity and feel should be determined after the heat treatment and the water wash are finally done. The elasticity of the printing surface can be adjusted according to the crack of the transparent paste and the white glue. , Increase the proportion of transparent pulp or base with transparent pulp, or increase the number of printing can increase the elasticity of printing.