Impact of Stone Enzyme Wash and Acid Wash Based on Denim Garments ()
1. Introduction
Denim clothes have a lot of demand in the market of regular clothes as well as in the fashion market. People of all ages, especially the youth have a great interest in the denim [1]. Different value-adding processes like industrial washing make the denim not only look beautiful but also impart some functional properties to the cloths. Already made cloths from solid color, from dyed or pigment printed fabrics, the clothes are washed by different clothe washing techniques [2]. Thus color, outlook and comfortability of the clothes are modified. As a result, a new outlook and appearance are produced in the clothes, which is not possible in any other method. Moreover, starch present in the cloths is removed by the washing. Moreover washed clothes could be worn after purchase directly from the store or shop. Some clothes shrink after wash, hence washed clothes could be purchased as per required size without consideration of further shrinkage [3].
Among different techniques of cloths washing, enzyme is chosen to fade color from all over the cloths in a regular manner and to polish the surface of the fabric [4]. In stone washing, denim cloth is washed along with pumice stone in industrial washing machine. During washing, the denim and pumice stones are spun together in the washing machine and produce better distressed look. To minimize the unwanted wear and tear of the cloths due to the presence of pumice stone in the wash bath, the washing conditions should be set correctly and carefully [5].
Using pumice stone causes wear and tear of the cloths and the machine surface. Enzymatic treatments have a lot of advantages over stone washing but the stone has a different irregular effect on the cloths which is very difficult to achieve with only enzyme [6]. As only stone causes harm to the cloths and machine, then using enzyme with the stone can bring the desired effect quickly with minimum harm to the cloths and machine. So, using enzyme and stone both in the same bath helps to achieve the required shade in a comparatively short time with wear and tear of the cloths within a tolerable range [7].
During Acid wash, pumic stones are used. By the action of pumic stones, an irregular fading effect is developed on heavy clothes like denim, thick canvas/twill, and sweater [8]. The pumic stones act as a brushing action on the cloth fabric surface. The area where more brushing action takes place there more discolor or fading effect is developed and the area where less brushing action takes place less brushing action and takes place less fading effect will be developed. The multi-layer fabric areas like collar, calf, pocket, placket, side seam, etc., area will be brushed more than the single layer areas. As a result, a irregular fading effect will be developed on the clothes fabric surface. Thus in this way, a fading effect may be developed on the cloth by acid wash technique [9].
This paper investigates the impact of enzyme-pumice stone wash on the physical and mechanical properties of denim cloths as these properties determine the wearers’ feel and life of the end product [10]. The minimum loss in the strength and fabric weight is preferable as well as other functional properties should be unharmed or should improve. Besides, the outlook of the clothes should be as per the demand. Meeting these parameters at an acceptable point is a very difficult task but better and optimum process control in enzyme-stone washing can solve that [11].
2. Materials and Method
To perform a successful experiment the following materials, instructions and methods are used in this project.
2.1. Raw Materials
97% cotton and 3% elastane denim fabric were used. These comprised bluish denim fabric, GSM 358, 3/1 warp faced S-twill, construction 72 × 40/9 × 7, fabric width 57 inch. Then sewn 2 leg panel.
2.2. Working Place
Washing Laboratory Departmental Pacific Jeans Ltd., CEPZ, Chittagong.
Types of machines used for washing which are shown below in Figure 1, Figure 2 and Figure 3.
2.2.1. Sample Washing Machine
Specification:
Name of the machine: Washing machine;
Brand: Mathis;
Origin: Switzerland;
Model: GW-5;
Serial No: 140472;
Rated Power: 3W-380V;
Weight: 55 Kg.
2.2.2. Dryer
Specification:
Name of the machine: Dryer machine;
Brand: SIEMENS;
Origin: China;
Model: WD12D523.
2.3. Machine Used for Testing Which Is Shown Below in (Figures 4-7)
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Crock Meter Specification: Brand: GESTER; Model NO.: GT-D05; Origin: China.
Figure 4. Crock Meter
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ph Meter Specification: Brand: EIT; Model NO.: pHG-1911X; Origin: New Zealand.
Figure 5. ph Meter.
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Tensile Strength Tester Specification: Brand: TESTEX; Model NO.: TF002; Origin: China.
Figure 6. Tensile Strength Tester.
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Tear tester Specification: Brand: TESTEX; Model NO.: TF-140A; Origin: Chaina.
Figure 7. Tear tester.
2.4. Stone Enzyme Wash
A Leg panel was taken for this experiment which is 200 gram. At first, the leg panel was taken for desizing treatment then Stone enzyme wash is done. After washing and drying, various test is done. The process parameters are given below.
2.4.1. The Process of Stone Enzyme Wash
Desizing
Fabric weight: 0.2 kg;
Water: 1.8 liters;
Temperature: 50˚C;
Desizing agent: 1.08 gm;
Anti-Back staining agent: 1.8 gm;
Time: 15 min.
Stone enzyme wash
Water: 1.6 liters;
Pumice stone: 0.1 kg;
Temperature: 45˚C;
Neutral Enzyme: 2.7 gm;
Anti-Back staining agent: 1.44 gm;
Acetic Acid: 1.08 gm;
Time: 15 minutes.
Bleach wash
Water: 1.6 liters;
Bleaching agent: KMnO4 (18 gm);
Temperature: 60˚C;
Time: 10min;
Neutralization;
Sodium Hyposulphite (5.4 gm) is used for neutralizing.
Hydro extraction
Hydro-extraction is done for 1.5 min to extract all the excess water from the fabric.
Dryer
Steam drier is used to dry the fabric. Machine is run for 20 minutes.
2.4.2. Flowchart for the Whole Process
1) Desizing
Garments are loaded
↓
Water is added (1.8 liter)
↓
Machine started running
↓
1.08 gm Soda Ash added
↓
1.8 gm Anti back staining agent added
↓
Steam to raise temp 50˚C
↓
Process time 15 minutes
↓
Drop liquor
↓
Wash down twice
2) Stone Enzyme wash
Garments loading
↓
Water is added (1.6 Liter)
↓
Machine started running
↓
2.7 gm Neutral Enzyme added
↓
gm Anti back staining agent added
↓
1.08 Acetic acid added
↓
Steam to raise temp 45˚C
↓
Process time 20 minutes
↓
Drop liquor
3) Bleach wash
Water is added (1.6 Liter)
↓
Machine started running
↓
18 gm KMnO4 added
↓
Steam to raise temp 60˚C
↓
Process time 10 minutes
↓
Drop liquor
4) Neutralization
Water is added (1.8 Ltr)
↓
Machine started running
↓
Sodium Hyposulphite added
↓
1 Kg Salt added
↓
Steam to raise temp 50˚C
↓
Process time 10 minutes
↓
Check Shade
↓
Drop the liquor
5) Drying
Garments are then taken out
↓
Hydro extracted for 1.5 min
↓
Send to dryer for 20 minutes
2.5. Method of Acid Wash
A Leg panel was taken for this experiment which is 200 gram. At first, the leg panel was taken for desizing treatment then stone wash and acid wash is done. After washing and drying, various test is done. The process parameters are given below.
Process of Acid Wash
Desizing
Fabric weight: 0.2 kg;
Water: 2 liters;
Temperature: 60˚C;
Desizing agent: 2 gm;
Anti-Back staining agent: 2 gm;
Time: 20 min.
Stone wash
Water: 1.6 liters;
Temperature: 25˚C;
Metabisulphate: 8 gm;
Time: 5 min.
Acid Wash
Water: 0.26 ltr;
Acetic Acid: 26 gm;
potassium permanganate: 6.5 gm;
Thermocol balls are put into the washing machine;
Temperature: 25;
Time: 10 min.
After two rinse wash we do the neutralization process with sodium Meta bi sulfite. Then treated denim leg panels were rinsed two times.
Neutralization
Water: 1.6 liters;
Temperature: 25˚C;
Metabisulphate: 8 gm;
Time: 5 min.
Softener
Water: 1.4 liters;
Temperature: 25˚C;
Acetic Acid: 0.84 gm;
Softener: 1.4 gm;
Time: 5 min.
Hydro Extracting and Drying Processes
Extracting and Drying
Process flowchart of Acid Wash
Loading
↓
Desizing (If Necessary)
↓
Conditioning of the garments
↓
Stone Preparation
↓
Acid Wash
↓
Neutralization Of By-product (MNO2)
↓
Neutralization
↓
Finishing/Softening
↓
Drying.
2.6. Method of Testing
2.6.1. Shrinkage
A square of 10" × 10" is marked on the fabric samples using permanent marker before washing.
The length and width of the square are measured after washing.
2.6.2. Tearing Strength
Denim Fabric;
Knife;
Tear template;
Tear tester.
2.6.3. Rubbing Test
L-Histidine hydrochloride monohydrate: 0.5 g/L;
Di-sodium hydrogen orthophosphate di hydrate: 2.7 g/L;
Sodium chloride: 5 g/L;
Time: 4 hrs;
Temp: 37˚C.
2.6.4. Color Fastness to Wash
Sample dimensions– 6" × 2".
Washing parameters:
Temperature: 49˚C;
Time: 45 min;
RPM: 40;
Steel Ball: 50 pcs;
Dia of steel ball: 6 mm.
2.6.5. pH Test
Machine used—Mettler Toledo pH meter.
250 ml distilled water taken and boiled for 10 minutes. Then 10gm sample is cut in small pieces in 2 batches and added to the water one batch at a time and kept under water for 10 minutes. The temperature has to be moderate and the sample is cooled after taking out of the water.
3. Results and Discussion
3.1. Results
Shrinkage percentage test report which is shown below in Table 1.
Tearing Strength Test report which is shown below in Table 2.
Colorfastness to Rubbing Test report which is shown below in Table 3.
Colorfastness to wash test report which is shown below in Table 4.
pH test report which is shown below in Table 5.
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Table 1. Test report for shrinkage percentage.
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Table 2. Test report for Tearing Strength Test.
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Table 3. Test report for colorfastness to rubbing
3.2. Discussion
3.2.1. Shrinkage
From the shrinkage test done on 10" × 10" sample, it found out both lengthwise and widthwise shrinkage occurred in the fabric. But the stone enzyme wash shrinkage percentage is higher than the acid wash which is shown below in Figure 8.
3.2.2. Rubbing Test
Here the crock meter is used to test the rubbing fastness on the fabric in both dry and wet condition. During stone enzyme wash color fastness of rubbing very good in dry condition and fairly good in wet condition. During acid wash color
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Table 4. Test report for colorfastness to wash.
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Figure 8. Graphical comparison for shrinkage percentages of both washes.
fastness of rubbing fairly good in dry condition and very poor in wet condition which are shown below in Figure 9.
3.2.3. Tearing Strength Test
Here checked both the warp way strength and weft way strength after wash. In warp way and weft way strength, acid wash sample higher than stone enzyme wash sample strength which are shown below in Figure 10.
3.2.4. Color Fastness to Wash
After washing the leg panel under laboratory condition, we used the gray scale to measure the color fastness to wash where it scored 4.5 for stone enzyme and 4 for acid wash that means stone enzyme sample is very good and acid wash sample is good. That means, after both washing the leg panel shows considerable performance to color fastness to wash which are shown below in Figure 11.
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Figure 9. Graphical comparison for rubbing percentages of both washes.
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Figure 10. Graphical comparison for tearing strength of both washes.
3.2.5. pH Test
We checked the pH of the leg panel surface using the pH meter and the result was slightly different for the two washes. But the variation was 0.6 and in both cases the fabric was slightly acidic at 2.2 and 2.8, which are shown below in Figure 12.
4. Conclusions
The aim of this project is to observe the impact of stone enzyme wash and acid wash on denim apparel characteristics. For that purpose, three same denim fabrics with twill 3/1 construction are made and after washing, changes in the characteristic of denim fabric have been observed. All washing treatments indicated
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Figure 11. Graphical comparison for color changes of both washes.
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Figure 12. Graphical comparison for pH of both washes.
great influence on the tear strength, weight loss of fabric because of the variation of chemical, washing process, time, temperature and fabric.
Finally, in denim washing our country has a bright future due to wide spread market of denim garments. We need thorough knowledge of denim treatment process and also of the fashion going around the world. And this project will be a guideline for those who are interested in this sector. We believe that this project will be a guideline for the washing plants in understanding and doing various treatments.
In this paper, the impact of Stone Enzyme wash and Acid wash is observed. From this study, it is found that by the treatment of stone enzyme and acid the constructions of the garments are not changed a lot except GSM. On the other hand, although strength of the garments is reduced, it is within the acceptable range. Shrinkage of the garments does not exceed the required level after treatment. So stone enzyme and acid washing produce moderately aged looks of the garments as well as comfort.