Before the same when dealing with the same grey cloth dyeing, dyed dark, such as when dark green, Navy Blue and black, tend to have a white spot, especially when applying the activity of dispersing/two-bath dyeing, white spots more obvious. There are two white spots may: (1) size not divisible, and (2) present on raw cotton cotton died. The so-called “death of cotton”, namely cotton bolls in the process of growth resulting from hypoplasia of stiff cotton. Strictly speaking, death is not dyeing with reactive dyes of cotton, and direct dye dyeing part die cotton you can rely on the van der Waals forces. Therefore, the former than the latter marked with white dots. If such defects, especially after heat setting, more difficult to repair. To prevent white spot, before the first of all, should be strengthened. Because both the removal of slurry on the fabric, or on the removal of raw cotton to die cotton, fabric pretreatment has very close relations. Following is the formulation and process of polyester-cotton fabric pretreatment conditions. Prescription/g ¡¤ L-1 (1) (2) of NaOH (flakes) T1~21~2H2O2 10~154~6Na2CO32~32~3 permeability agents (30%) 3~53~5 YX282~3-188-3~5 process of scouring enzyme scouring agent: prescription (1) charging at room temperature, to 1.5 ¡æ/min heating to 100 ¡ã c, heat scouring 60~90min fully washed, dyed. 1:10 bath ratio (to the same below). Recipe (1) suitable for desizing. Prescription (2) feeding at room temperature, a warming of 1 ¡ã c/min to 100 ¡æ, scouring 60min insulation, cooling to 85 ¡ã c, temperature washing once new bath, joining Na2S2O4 of 0.3g/L processing 15min, removal of residue on fabrics of H2O2 and , finally, fully washed, dyed. Prescription (2) suitable for removing of dead cotton. With the above two after treatment, dispersion/fabrics made of dyed polyester or direct one-bath dyeing. Practice has proven that through this pre-treatment, 19.4texx19.4tex268 root/10cmx268 root 29texx29tex425 root/10cmx228 root/10cm and/10cm plain cotton twill fabric conditioning rate can reach 11.5%~13.0%, capillary effect can also be reached 10.5~12cm/30min, whiteness value of around 70, dyeing of full compliance with requirements. Dyeing and finishing of cotton fabrics on dyeing Navy Blue and black, basically no obvious white spots. But in production also need to note the following several points: (1), H2O2 can remove part of the slurry and dead wool, but the amount must be appropriate. Such as excessive, combined with the raw cotton cotton content and not be seen dead on, tends to make fabric hole (needle), and even makes the strong reduction in raw cotton. (2), and death of cotton fabric sizing agent removal, rely mainly on the role of alkaline agents and surfactants. In order to make the pharmaceutical treatment bath play a role, you should add penetrant t. Not only can it help improve the dyeing defects caused by the death of cotton, and penetration rapidly, especially suitable for high count and high density fabric and cotton textiles with poor quality. (3), select Yin/non-ionic scouring agent complex. It can effectively emulsification, dispersion from both impurities, dirt and fibers from the oligomer, and inhibition of these substances can also stain again. (4), pretreatment baths must join in soda, water softener, detergent effects. In determining when dyeing recipe and process, if the requirements for colour fastness to high, preferably dispersing/two-bath dyeing of reactive dyes. In order to overcome the reactive dyes for cotton died in cotton and response capacity of defect-free, you can in the process of reactive dyeing process of SOAP-boiling, add the amount of shade similar to the direct dye, because it after pretreatment of die of dyeing of cotton there. In implementing the technology required attention: (1), SOAP boiling time to extend 10min of reactive dyes, direct dyes to ensure joined fully in contact with the death of unreacted cotton, increase the rate of dyeing. (2), due to join the direct dye, overall colour fastness to reduce, so thoroughly after cleaning of fabrics, also required for the purposes of Yang charged fixing agent processing. In fact, in order to further improve the fastness of reactive dyes, especially wet rubbing fastness, at present the enterprise are extensive use of additives such as fixing agent for processing. (3), if the dyeing of fabric softener were required after treatment, it is recommended that solid color, soft finish combined. Because fixing most of Yang charged, softeners or Yang of load, or non-ionic, use does not affect their respective results.