Common problems and solutions in the use of printing materials

1: Color migration color is added to the glue for coloring, some colors will have color migration, dark color will migrate to light color flower position or colored printing will migrate to white flower position, or the printed color will run to the unprinted fabric It's called color migration. In order to avoid color migration during production, the color must be tested for resistance to glue migration.

Test method: color (3%) + transparent paste (97%) - printing - flash drying - cover white glue (100%) - self-drying - 130 ℃ × 3 seconds pressing. It is divided into 5 grades and the migration phenomenon can be seen with the inner eye. It is not recommended to be used for glue printing. For water slurry (pigment printing) printing, pay attention to white or light-colored fabrics. The test results of different glues will vary, and the difference is not too. Most fluorescent colors do not migrate from glue, so it is necessary to communicate clearly with customers before production.

2: Heat treatment discoloration Most of the glue printing needs to be heat treated. Some colors have poor heat resistance, and there will be serious color difference after the treatment, especially when mixed with a thick plate of thermosetting ink for printing. Therefore, it is necessary to carry out heat resistance test on the color. The test method is: 37% white glue + 60% transparent paste + 3% color, after natural drying, heat treatment at 180 ° C for 30 seconds, the highest level is 5, and the level 5 is indistinguishable with the naked eye before and after heat treatment

3: Light fastness test At present, many companies are accepting orders from brand companies or European and American orders, and the requirements for light fastness are relatively strict. If customers have such requirements, they can ask the supplier to provide the light fastness data of the pigment or the third party test report, or print a good sample. Go to a tripartite testing agency for testing. The general test method and standard are: JIS L-0842 carbon arc lamp for 20 hours

4: Solvent resistance test At present, more and more clothes are taken for dry cleaning. If the pigments have poor solvent resistance, the clothes will fade and change color after dry cleaning, resulting in dissatisfaction and complaints from consumers. Therefore, the clothing company will take samples for inspection before receiving the goods, and only receive the goods after passing the test. If the customer has this requirement, the supplier can ask the supplier to provide the light fastness data of the pigment or the third-party test report, or can print the printed sample and send it to the third-party testing agency for testing. Test method: JISL-0860 (tetrachloroethylene, 40℃ for 30 seconds)

5: Pull-out resistance test Before doing the pull-out test, the color type should be tested for pull-out resistance. Some pigments are not resistant to reducing agents, and they will become two colors when they are overheated, for unnecessary losses. Therefore, it is necessary to test the pull-out resistance of color samples before opening the goods. Test method: Add 5% of carved white powder and steam at 105 ℃ for 8 minutes at normal pressure, or heat bake at 170 ℃ for 3 minutes.

Other precautions: such as environmental protection properties, aromatic amines, formaldehyde, heavy metals, APEO (alkylphenol polyvinyl chloride ether). There is also a reaction with the slurry, some of the pigments will react with the slurry, thickening and thinning after stirring, and gelatinization. Wet and dry friction, etc.