Water-based ceramic ink printing failure causes and solutions (a)

As far back as the late Neolithic Age, our ancestors used colored materials to decorate ceramic products; in the Han Dynasty, the silver glaze green glaze was applied on the Han Tao, which was made of a natural copper compound coloring agent; and Tang Sancai used iron, Copper compounds are yellow and green, and blue is obtained from the use of cobalt-containing materials. By the end of the Song Dynasty, people used natural drilling to make famous blue and white color pigments. Today, ceramics packaging and printing, in addition to manual painting, spray color, In addition to the gravure printing that appeared in recent years, the majority of screen printing has followed the traditional process of oil-based ink coloring.

With the implementation of the global VOC standard, organic, toxic gases and dust emitted during the firing (junction) process of oil-based screen printing ceramic inks have seriously polluted the space environment in which human beings live. In this regard, water-based ceramic screen printing inks and water-based gravure inks that use water as a dispersion medium (linking material) have been successively put into the standard for water-based ceramic screen printing inks and Shuibo Printing inks. There is still no satisfactory classification method and quality. standard. For this reason, the author discovered from the emerging Jingmen Jiantao base in Hubei Province and the enterprises in Quanzhou, Fujian Province and Foshan, Guangdong Province that the following problems exist: In screen printing and gravure printing, each line is a technology blockade, and the market is the same. Varieties, often due to the differences in the methods of identification, appear to have problems with one or the other printing technology and bring about different printing qualities. In response to these problems, and combining the bit of experience gained through hands-on practice, the author proposes the causes and solutions of failures in the printing of water-based ceramic screen printing inks, and discusses with peers.

1. There is a gap between product color and sample color

If the color is light, the ink consistency should be increased during screen printing. Normally, screen printing should be repeated once.

Because the ceramics are generally fired in two parts after printing, they are first fired at 700-800°C and then fired at 1,100-1300°C. Another method is to use a high temperature of 1100-l250°C for burning, and then use 900-1000°C for glaze. People's mines are * 700-800 degrees Celsius on the glaze porcelain glaze, said the glaze under the glaze firing temperature l000-1300 °C. Therefore, the waterborne screen printing ink system on the underglazed porcelain has a high burning temperature of the colorant, although various colors can be expressed freely, and the glaze coloring material is generally composed of a colorant and a water dispersion medium, in particular, the screen printing water based ink. The level of the pit value also affects the difference between the color tone of the ceramic screen printing and the sample.

2. There are differences in the specifications of ceramic decorative drawings and samples

The length of time for mixing ball mills with screen printed water-based ink (linker medium) and the number of screen meshes is directly related to the uniform, uniform melting of the water-based ceramic screen printing ink system particles. The molecular structure characteristics of the water-based ink system medium, whether it is easy to mix, acid and alkali resistance, the size of the expansion and contraction, etc. are all related to the differences between the decorative graphics and the samples exhibited on the ceramic after firing. Water-based ink is usually required to be controlled at 20-60um.

3, after firing (knot) (Alice curling) curl

The scalloped angle of ceramic products after sintering (finishing) is mostly screen printed ceramic underglazed and water soluble inks. After metal oxide pigments are mixed with dispersing medium (grinding material), they are screened or gravure printed. It is often due to the fact that the moisture content in the ink system is so large that the difference in the coefficient of expansion between the glaze and the blank is caused. Similarly, if there is a difference in the coefficient of expansion of the screen printing decals, it will also cause the edges of the ceramic products to be printed and fired (knotted).

Note: The underglaze coloring screen process is mostly used to decorate dry billets - burned blanks or fired white porcelain, while repelling with glazes, or printing and firing. This requires that the glaze does not react with the glaze at the temperature of the glaze, and it cannot be blurred by the flow of the ink film.