Effect of pectinase biological pretreatment on cotton fabrics on dyeing
Abstract: Today, when “green” processing and “clean” production are advocated, pectinase refining is a promising and ecologically friendly clean production method. The article introduces the structural characteristics of cotton fiber and the action mechanism of pectinase, and optimizes the pectinase refining process of cotton fabrics through single factor experiments and orthogonal experiments. Cotton fabrics were treated with the optimized pectinase refining process and dyed with direct dyes and reactive dyes. The effect of enzyme treatment on the dyeing properties of cotton fabrics was discussed. At the same time, the dyeing properties of cotton fabrics dyed after alkali treatment were compared. Compare.
Keywords: pectinase; cotton fabric; dyeing performance; wool effect; strength
0 Foreword
Cotton fabric is soft and breathable , good hygroscopicity, comfortable wearing and other advantages, it occupies an important position in textile fabrics. At present, the pre-treatment of cotton fabrics generally adopts the traditional process of high temperature and strong alkali. This process not only makes the production conditions harsh, but also discharges a large amount of strong alkaline wastewater, affecting the ecological environment and human health. Today, when “green” processing and “clean” production are advocated, it is urgent to find an efficient and environmentally friendly cotton fabric scouring method. The biological enzyme treatment conditions are mild, the process is short, the equipment is simple, the energy consumption is small, and the wastewater is less. It can effectively avoid fiber damage during the treatment process. The fabric after biological enzyme treatment feels fluffy and soft, which can increase the added value of cotton fabrics and make the product Develop towards diversification, functionality and high-end. This article uses orthogonal experiments to optimize the pectinase scouring process of cotton fabrics, and discusses the impact of pectinase biological pretreatment on the dyeing properties of cotton fabrics.
1 Experimental Part
1.1 Fabric
Pure cotton muslin
1.2 Drugs
Alkaline Pectinase (70,000 international units/g, provided by Guangzhou Tianhe Yuantian Enzyme Preparation Factory), acetic acid, sodium acetate, hydrogen peroxide (30%) (the above are all analytical grade), potassium dichromate, sodium hydroxide, sodium silicate , trisodium phosphate, sodium chloride, sodium carbonate (all of the above are chemically pure), penetrating agent JFC, Pingpingjia O, soap powder, direct lake blue 5B, active brilliant orchid KN-R, active yellow M-5R (the above are all for industrial products).
1.3 Instruments and equipment
YG026-2500 fabric strength meter, ZBD whiteness meter, PHS-25 acidity meter, HH-S electric constant temperature water bath, TC-PIIG type Fully automatic colorimeter, Y571B friction fastness tester, AS-024 normal temperature prototype, CS1012 electric blast drying oven, 721 spectrophotometer.
1.4 Treatment process
1.4.1 Alkali desizing process
Process flow: gray cloth → padding with dilute alkali solution (sodium hydroxide 10 g/L, penetrant JFC 2 g/L, 80℃~85℃, two dips and two rollings, the rolling residue rate is 110%)→steaming (100℃~102℃, 25 min,)→hot water washing (90℃, 5 min, 2 times ) → cold water washing → drying
1.4.2 Alkali scouring process
Process flow: desizing cloth → impregnated with alkali scouring liquid (sodium hydroxide 10 g/L, penetrant JFC 2 g/ L, liquor ratio 1:20, temperature 95℃~100℃, time 1 h)→hot water washing (60℃~70℃)→cold water washing→drying
1.4.3 Bleaching process
Process flow: alkali scouring cloth → soaked in hydrogen peroxide solution (hydrogen peroxide 30%, 6 g/L, penetrant JFC 2 g/L, sodium silicate 56 g/L, liquor ratio 1:20, time 1 h, temperature 80 ℃~85℃)→hot water washing (60℃~70℃)→cold water washing→drying→performance test
1.4.4 Pectinase refining process
Process flow: desizing cloth →Pretreatment (boil in boiling water for 5 min) →Impregnate enzyme solution (pectinase 4 g/L~12 g/L, penetrant JFC 2 g/L, pH 4~10, temperature 50℃~60℃, time 60 min~90 min, liquor ratio 1:20) → inactivate the enzyme (boil in boiling water for 2 min) → wash with hot water (60℃~70℃) → wash with cold water → dry → performance test
Pectinase The bleaching process after treatment and the bleaching process after alkali refining process are the same as 1.4.3.
1.4.5 Dyeing process
(1) The direct dye dyeing process is shown in Table 1, and the process curve is shown in Figure 1.
The post-processing process is color fixing, hot water washing, cold water washing and drying.
Fixation formula: 3% copper sulfate (owf), 2% 30% acetic acid (owf), temperature 60℃~70℃, time 30 min, liquor ratio 1:50.
(2) The reactive dye dyeing process is shown in Table 2, and the process curve is shown in Figure 2.
The post-processing process is soaping, washing with hot water, washing with cold water and drying.
Soap boiling process: soap powder 2 g/L, temperature 95°C, time 10 minutes.
1.5 Performance Test 1.5.1 Whiteness
The whiteness of the fabric is measured on a ZBD whiteness meter. 1.5.2 Gross effect
According to the standard timing method (30 minutes). The larger the wool effect value, the better the hygroscopicity of the fabric. 1.5.3 Breaking strength
Measured on YG026-2500 fabric strength machine. 1.5.4 Dyeing percentage
Dyeing percentage = (1-A/B)×100% where:
A—absorbance of the residual liquid after dyeing;
B—Absorbance of blank dye solution. 1.5.5 Fixation percentage
Fixation percentage = (1-A/B)×100% where:
A—absorbance of the residual liquid after fixation;
B—Absorbance of blank dye solution. 1.5.6 Color difference
Measured on the TC-PIIG fully automatic colorimeter (using alkali scouring dyed fabric as the standard sample). 1.5.7 The soaping fastness is according to GB250-84=ISO 105/A02-1982 “Gray Sample Card for Evaluating Discoloration”, GB251-84=ISO 105/��. The dyeing percentage and color fixation percentage of cotton fabrics after dyeing are generally low. This is because pectinase and alkali do not remove pectin and other impurities on cotton fabrics well. Cotton fabrics after enzyme scouring and alkali scouring Since it has not been bleached with hydrogen peroxide, impurities such as pectin affect the penetration of dye into the interior of the fabric. In addition, we can see from the appearance of the dye that the dyeing depth of cotton fabrics after enzyme treatment is slightly higher than that of alkali refining, and the luster is brighter and the color is brighter than that of alkali refining. The appearance effect is obviously better than that of alkali refining.
It can be seen from Table 13 that after cotton fabrics are treated with enzymes and alkali respectively, if they are dyed under the same conditions, the washing fastness and rubbing fastness are not much different. Cotton fabrics dyed with reactive dyes have better washing fastness and rubbing fastness, especially the washing fastness and dry rubbing fastness are above level 4, and the wet rubbing fastness is slightly worse than the dry rubbing fastness. However, when dyed with direct dyes, the washing fastness and rubbing fastness of cotton fabrics are relatively poor, which is also the biggest shortcoming of direct dyes.
3 Conclusions
(1) When refining pectinase, attention should be paid to the influence of various factors and suitable conditions should be found to maximize enzyme activity. The optimal process for scouring cotton fabrics with pectinase is: pectinase 9 g/L, penetrating agent JFC 2 g/L, pH value 8, temperature 50°C, and time 1 h.
(2) The color of enzyme-treated fabrics is darker than that of alkali-treated fabrics; the fixation percentage of reactive dyes and the dyeing percentage of direct dyes are both greater than that of alkali-treated fabrics. As the dye concentration decreases, , △L, △a, △b, and △E show an increasing trend, and the color difference between enzyme-treated fabrics and alkali-treated fabrics is large.
(3) After cotton fabrics are treated with enzymes and alkali respectively, if they are dyed under the same conditions, the washing fastness and rubbing fastness will be almost the same. Cotton fabrics dyed with reactive dyes have better washing fastness and rubbing fastness, especially the washing fastness and dry rubbing fastness are above level 4, and the wet rubbing fastness is slightly worse than the dry rubbing fastness. The washing fastness and rubbing fastness of cotton fabrics dyed with direct dyes are relatively poor.
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