Screen printing defects analysis - osmotic

2. Penetration (diffusion, dip )

The edge of the outline of one or more color patterns on the fabric expands outwards, forming a rough color with the same color and lighter color on all or part of the edge of the pattern. When two patterns of different colors are connected or adjacent to each other A third hue appears. This phenomenon is called osmosis.

Reasons: (1) The content of thickener in the paint printing paste is insufficient or the amount of water is too much, and the paste viscosity does not meet the required requirements. Due to the faster flow speed of the printing paste, the pattern color paste on the fabric flows more toward the outside of the pattern edge, and the pattern outline is not clear. 2 During the printing operation, the speed of the squeegee is slow, the pressure is large, the amount of slurry is large, the frequency of reciprocation is frequent, etc., and the pattern will give too much slurry. Because the slurry load exceeds the amount of pulp on the fabric, the color paste bleeds out of the pattern. . (3) When the pattern area is large and the fabric has a large amount of pulp, the fabric after printing is stacked for a long time, so that the humidity of the fabric is increased, and the pattern color paste is easily spread outward. 4 When the printing paste is mixed, the dispersion is uneven or the printing paste is directly diluted with water, which affects or destroys the stability of the printing paste in the emulsified state. 5 When printing synthetic fiber fabrics and synthetic fibers on natural fiber blends or interlaced fabrics, because the synthetic fibers are hydrophobic, the printing paste can be easily osmotized into the pattern. 6 The organization of thin fabrics, sparse suction capacity is relatively small, particularly sensitive to the amount of pulp, a little more than the amount of colorant is prone to osmotic.