1. Causes of holes in dyeing and finishing:

(1) Excessive dosage of acid and hydrogen peroxide;

(2) High iron ion content in the water;

(3) If the holes appear regularly, there is a problem with the equipment;

(4) Improper temperature + time parameters;

(5) Holes in bleaching are mostly caused by the reaction of hydrogen peroxide with iron ions;

(6) Excessive purity of hydrogen peroxide and alkali;

(7) Whether a water softener is used in pretreatment and dyeing; the metal ion content of the water used may be too high;

(8) Local rapid decomposition of hydrogen peroxide caused by heavy metal ions, producing holes.

2. Analysis of holes caused by hydrogen peroxide bleaching:

(1) The fabric carries oil stains with copper, iron and other heavy metal ions before bleaching, or contacts copper and iron equipment during bleaching;

(2) The hydrogen peroxide concentration is too high, or steaming after bleaching is too long, or superheated steam is used;

(3) If the greige fabric is mercerized before bleaching, the alkali concentration must be controlled carefully;

(4) Iron and copper ions in the bleaching bath catalyze the decomposition of hydrogen peroxide locally, so chelating agents and stabilizers should be used;

(5) Calcium and magnesium hardness in the water should be removed before bleaching.

Prevention: pre-treat the water, control hydrogen peroxide and alkali concentrations precisely, keep bleaching time and temperature within limits, avoid metal contact, and use stabilizers and chelating agents suitable for the process.