Pretreatment process for combed polyester cotton bleached cloth

The invention relates to a pretreatment process for combed polyester cotton bleached cloth. The pretreatment process comprises the procedures of singeing, desizing, bleaching, mercerizing and heat-shaping, wherein during desizing, the enzyme-desizing cold-dwelling process that desizing anzyme and a penetrant are added into the desizing procedure is adopted; in the bleaching procedure, the following materials are adopted: 0.2-0.4 part of potassium borate serves as the bleaching liquor, 0.8-1.2 part(s) of diethylenetriaminepenta acid (DTPMP), 0.8-2 part(s) of acrylic acid maleic acid copolymer, 0.5-1 part of 1, 5-anhydrous glucitol, 1-2 part(s) of caprolactam activator, 0.4-0.7 part of tetraacetylethylenediamine (TAED), 3-8 parts of sodium hydroxide, 3-7 parts of hydrogen peroxide and 900-1000 parts of water. When the pretreatment process is used for processing fabrics, prominent damage to the fabrics is small; as enzyme desizing is adopted, the desizing ration is improved; the bleaching liquor adopted in the bleaching procedure can effectively improve the whitenness of the fabrics; meanwhile, the pretreatment cost is lowered.