What are the causes of holes in dyeing and finishing?
First, there are several reasons for the holes in the dyeing and finishing:
(1) The amount of acid oxygen water is too high;
(2) There are more iron ions in the water;
(3) If there is regularity in the hole, there is a problem on the equipment;
(4) The "temperature + time" parameter is improper;
(5) The occurrence of holes in bleaching, in most cases caused by the reaction of hydrogen peroxide with iron ions;
(6) excess purity of hydrogen peroxide and alkali;
(7) Whether pre-treatment and dyeing have added softener, and the content of metal ions in the water may be too high;
(8) The local decomposition of hydrogen peroxide caused by heavy metal ions causes rapid breakage.
Second, the reasons for the hole caused by hydrogen peroxide bleaching are analyzed:
(1) Oil stains stained with heavy metal ions such as copper and iron before bleaching; or contact with copper and iron during bleaching.
(2) The concentration of hydrogen peroxide is too high, and the steaming time after bleaching is too long or superheated steam is used.
(3) If the grey cloth is mercerized before bleaching, the water is not clean and uneven after mercerizing, so that the PH value of the cloth surface is too high and the amount of alkali is too much.
(4) Improper selection of stabilizers or poor stability of stabilizers, resulting in accelerated decomposition of hydrogen peroxide.
All of the above points may cause holes in the cloth surface, but heavy metal ions are more harmful.