The pre-treatment of polyester-cotton knitted fabrics and disperse dye dyeing are performed in the same bath, which can save dyeing time and energy and improve production efficiency. The selected alkali-resistant and hydrogen peroxide-resistant disperse dyes are refined and dyed using additives that have good scouring effect, can effectively remove cotton fiber wax and pectin, and have a certain promotion effect on oxygen bleaching and good dispersion effect on disperse dyes. Research on the same-bath dyeing process, comparing the scouring and bleaching performance of cotton fabrics and the color and light stability of disperse dyes, apparent color depth K/S value, dyeing fastness, etc. The results show that the dyeing effect of the one-bath oxygen bleaching, dyeing and polyester method is similar to that of the traditional dyeing method. The dyeing time is short, the process is simplified, the energy consumption is low, and it has the socio-economic benefits of energy saving and emission reduction.
The traditional dip-dying process for polyester-cotton knitted fabrics generally involves scouring and bleaching of cotton fibers and dispersion/reactive two-bath dyeing, that is, scouring and bleaching first, then dyeing polyester, and then overdying cotton. The advantage of this process is that it is clean and bleached. Both dyes can be dyed under optimal conditions and can obtain the highest color fixation rate and fastness level. There is sufficient room to choose disperse dyes and reactive dyes. The final dyeing effect can be obtained by reactive dyes. However, the disadvantages of the two-bath process are that the entire wet processing process takes a long time, which takes more than 10 hours. The production efficiency is low, the consumption of water, electricity, and steam is large, and the discharge of sewage is large.
1. Traditional process flow: oxygen bleaching → pickling → dyeing → reduction cleaning → pickling →Dye cotton→Soaping→Making cloth. 2. One-bath polyester-cotton bleaching and dyeing process. The one-bath polyester-cotton bleaching and dyeing process is to pre-bleach the fabric under alkaline conditions in the same bath as the polyester dyeing. After the dyeing is completed, reduction cleaning is omitted. After washing, the cotton is directly treated with reactive dyes. The fibers are dyed, and finally the remaining dispersed, floating colors of reactive dyes and some “oligomeric” impurities on the fabric are soaped.
Technical problems that need to be solved
1. One-bath bleaching and dyeing aid Preparation of agents. The method prepared can not only have good oxygen bleaching and scouring effects under high-temperature alkaline hydrogen peroxide conditions, but also enable disperse dyes to be evenly dyed on polyester.
2. Disperse dye screening. Screen the alkali resistance and hydrogen peroxide stability of disperse dyes under high temperature conditions.
3. The optimal process conditions for one-bath scouring, bleaching and dyeing.
4. Comparison of product quality and economic benefits using oxygen bleaching and dyeing of polyester-cotton knitted fabrics using one-bath method.
Test content
Alkali resistance stability test of additives, Alkali penetration resistance test, hydrogen peroxide resistance stability test, fabric capillary effect test, whiteness and strength test, weight loss rate test, oil removal test, disperse dye migration test, determination of relative unevenness of dyeing, dye fastness degree test.
Results and analysis
1. Preparation and dispersion of scouring agent Dye Screening Through the comparison and testing of various properties, the prepared scouring agent R meets the technical requirements and can be used in one-bath scouring and dyeing of polyester-cotton fabrics. The more than 40 disperse dyes screened can maintain a stable color under high-temperature alkaline hydrogen peroxide conditions. Polyester can be dyed based on this color, and a relatively mild reduction cleaning process can be omitted or used.
2. Quality analysis of dyed finished products uses the process in Figures 4 and 5 to compare with traditional process dyeing samples, and test its color difference CMC DE, soaping fastness, dry rubbing fastness, wet rubbing fastness, top Breaking strength, pH, shrinkage (lateral shrinkage and straight shrinkage), twist and other indicators, the results are shown in Table 1.
As can be seen from the above table, the color and light of the products produced through large samples meet the requirements, and other fastness tests, pH, bursting strength, and shrinkage rate , the torsion also meets the standards. Based on the above evaluation, the one-bath polyester-cotton bleaching and dyeing method is a good method for dyeing large samples. The dyed fabric samples are also qualified in all indicators and can be used for large-tank production.
3. Comparative cost analysis of the two production processes. Calculated based on the production of 1 ton of polyester-cotton knitted fabrics and a bath ratio of 1:10. Compare the comprehensive costs of the oxygen bleaching and dyeing polyester one-bath process with the traditional process, as shown in Table 2 shown.
Note: The disperse dyes used for dyeing polyester are selected from dyes in the factory, so the cost of the dyes used in the two dyeing methods is basically the same. The cotton covering process after bleaching and dyeing one-bath polyester is exactly the same as the cotton covering process after reduction and cleaning in the traditional process, and the dyeing cost is also the same, so there is no further comparison.
Summary
The one-bath dyeing process of polyester and cotton bleaching does not require polyester The reduction and cleaning process after dyeing allows hydrogen peroxide and disperse dyes to be alkaline dyed in the same bath, which greatly reduces the process flow and makes the operation more convenient. This dyeing process is short in time, effectively shortening the dyeing time by about 3 hours, requiring less energy such as water, electricity, and gas, improving production efficiency, saving energy consumption, and reducing dyeing costs. All indicators of the product meet standard requirements. </p
