The added value of yarn-dyed products is relatively high, and the visual effect of the fabric style composed of weave and yarn color is good. Therefore, with the improvement of consumption level, the proportion of yarn-dyed towels is constantly increasing, and the technical content of products is required to increase. The dyeing and finishing process is an important part of the production of pure cotton jacquard fabrics. It is very important to choose the appropriate process for improving the grade and added value of the product.
Pure cotton jacquard towels are required to be soft, drapeable and wear-resistant. Therefore, the product design choice is mainly plain weave, and then matched with various patterns.
Raw yarn (skein) → scouring → bleaching → dyeing.
Since cotton fibers contain impurities such as wax pigment and pectin, they must be removed before dyeing to improve the permeability of the fabric and meet the needs of dyeing, so the pretreatment process includes scouring and bleaching.
1) Scouring
The scouring uses a high temperature and high pressure cooking pot with a capacity of 1000kg. Scouring formula (every pot): caustic soda 100kg; soda ash 10kg; trisodium phosphate 6kg; Technological process: heating for 2h to 120℃, scouring for 4h, and washing with water.
After scouring, if it is white yarn, it has to go through a bleaching process, and if it is dyed yarn, it does not need to be bleached. When dyeing with reactive dyes, since the pH value of the yarn itself has a great influence on the dyeing rate and levelness during the dyeing process, it is necessary to strengthen the washing after scouring, and the directly dyed yarn must be washed until neutral.
2) Bleaching
Bleaching formula: hypochlorous acid (bleach) 1.6～2g/L; big soda (dechlorinating agent, 100kg cotton yarn) 6kg; hydrochloric acid (pickling agent) 2g/L. Process: chlorine bleaching (45min)→water washing (30min)→pickling (30min)→dechlorination (10min)→water washing, and finally wash to neutrality. After bleaching, the chlorine should be removed and washed with water until neutral.
3) Dyeing
Dyeing is dyed with environmentally friendly B-type reactive dyes. The dyes have two reactive groups and have considerable adaptability to changes in dyeing process conditions. The dye has good permeability and level dyeing to the fabric, and there is little difference in directness and permeability, so the compatibility of dyes is good, and the color matching is convenient. The color depth of the dyed products is stable, the exhaustion is good, and the color fixing rate is over 80%.
Taking Dahong as an example (100kg cotton yarn), the formula is: active dark red ZF-4BD 580g; active yellow ZF-4RFN 3120g; active blue ZF-2GLN 14g; Yuanming powder 80g/L; soda ash 20g/L. The dyeing process is as follows: dyeing at 70°C for 21 minutes, adding alkali to fix the color for 40 minutes, then soaping and washing. The management of dyed yarn should be strict, the dyed yarn should be clean and bright, the whiteness of white yarn should be good, and the water used for cooking, bleaching and dyeing should be strictly required, and soft water should be used (the water quality should be below 30×10-6). In terms of dyeing, it is necessary to strictly implement process standards to avoid chromatic aberration and color flower phenomenon. The dyeing and preparation workshops should be equipped with yarn selectors to correctly handle the color difference levels, so that the fabrics can meet the requirements of high-quality products.
1) Post-finishing process
Unloading grey cloth → grey cloth inspection → singeing → desizing (SLMH095 desizing and scouring combined machine) → drying (MH634 three-layer short-ring dryer) → setting (LMH722 short-ring pre-drying and setting machine) → pre-shrinking (Japan Xiaosonghou-160 pre-shrinking machine) → code cloth → finished product inspection → packing.
Because the floating line on the back of the product is long, and at the same time, in order to make the jacquard plump, the flower warp can not bear large tension, so the whole post-finishing adopts a completely loose finishing to prevent the thread from snagging and flattening the jacquard pattern.
2) Main process and process
Desizing: The product uses oxidized corn starch as the main slurry, the color of the dyed fabric does not change the original fabric color during desizing, and the surface gloss and hand feel are better, so amylase is selected as the desizing agent. The dosage of amylase was 3g/L, and the bath ratio was 20:1. The process is padding amylase → high temperature stacking → water washing. The stacking temperature is 60 ℃, the time is 40 to 50 minutes (the general product is 40 ℃, 30 to 40 minutes), and the water is washed at 70 to 80 ℃ for 2 grids, and the ordinary water is washed for 3 to 4 grids. In this process, heat preservation treatment is very important, because it takes a certain time for amylase to decompose starch, heat preservation treatment can make the enzyme preparation fully hydrolyze the starch on the fabric, so that the starch slurry can be easily washed away. After the starch slurry is hydrolyzed by amylase, it still adheres to the fabric and needs to be removed by water washing, so the water washing should be carried out at the highest possible temperature to promote the rapid removal of the hydrolyzate.
It should be noted that the floating line on the back of the fabric is long, the cloth channel should be minimized, and the cloth guide roller should not be taken, so the temperature should be increased and the stacking time should be prolonged.
Drying and Soft Setting: The fabric is dried under complete tension-free conditions. The purpose of softening finishing is to improve the hand feeling of the fabric, and the finishing is done on the LMH722 short-ring pre-baking and setting machine. First pad the softener, then pre-bake and shape. The residual rolling rate is 60% to 70%, and the drying room temperature is 150 to 160 °C. If the temperature is too high, the fabric is prone to discoloration; if it is too low, the setting effect is not good. The width of the falling cloth is 2-3cm larger than the width of the finished product.
Pre-shrinking: The fabric is pre-shrinked, on the one hand, it can ensure that the shrinkage rate is within the specified range, and at the same time, it can also improve the feel and luster of the fabric. The process flow is: cloth feeding → steam wetting → rubber blanket pre-shrinking → drying → cloth falling.
Code cloth: For code cloth, pay attention to the tension on both sides of the cloth and the smoothness of the cloth channel, to prevent the weft from being skewed, and to prevent the floating thread on the back of the fabric from being hooked.
The main features of the dyeing and finishing process of pure cotton yarn-dyed jacquard fabrics are that appropriate dyes and processes are used to improve the color fastness of the product; The pattern is full and round, and the technical requirements of small tension must always be run through in production to avoid flattening the jacquard.
The suede material we use to make floor mats can be used to print patterns, and it will also be dyed before making floor mats. For example, we reproduce the coral fleece used in memory foam floor mats. , No pilling, firm color, will not cause irritation and allergy to the skin. After treatment, it has very good water absorption performance, and there is only a slight hair loss problem.Generally, coral fleece needs to go through the process of white grey cloth → unwinding → sewing head → pre-setting → hemming → dyeing → soft-up → dehydration → edge pulling → drying → brushing → combing → shearing → shaking → shaping → finished product rolling.
1. Usually the low temperature type is used to dye the light color, the medium temperature type is used to dye the medium color, and the high temperature type is used to dye the dark color.
2. Different disperse dyes have different sensitivities to acid. In severe cases, discoloration or discoloration may occur. Therefore, the pH of the dye solution needs to be adjusted. When the pH value is 4.5-5.5, the dye solution is in the most stable state. state.
3. For PET fiber dyeing, the dyeing temperature and temperature rise control are very critical. Usually, the starting temperature is within 70-80℃, the medium color is 80-85℃, and Shenzhen is 85-90℃.
4. In the finishing process, it is necessary to strictly control the temperature and speed of each process.
5. We will adjust the use of various additives in the dyeing process to meet the requirements of flexibility, water absorption and color fastness according to the customer's requirements for the final use and characteristics of the product.
Polyester fabrics are widely used in various textiles and clothing fabrics due to their high strength, good resilience, excellent wear resistance, good dimensional stability and good wrinkle resistance. The dyeing of polyester cheese yarn is carried out on a high temperature and high pressure cheese dyeing machine by high temperature and high pressure dyeing method. Due to the compact structure of polyester fibers, disperse dyes are hardly dyed at low temperature.
Only when the temperature was raised above 90°C, the dye uptake gradually increased. When it reaches above 110 °C, the movement of the polymer segment in the amorphous region in the polyester fiber is intensified, which increases the micro-gap, reduces the resistance of dye molecules to diffuse into the fiber, improves the diffusion speed of dye molecules, and increases the dyeing rate of disperse dyes. increase rapidly. Satisfactory dyeing effect can be obtained only when the temperature reaches 130°C, the dye utilization rate is above 90%, the color is full, and the dyeing fastness is excellent.
1) Production materials and equipment
Polyester 100D network yarn, dyes, glacial acetic acid, leveling agent, reducing cleaning agent, antistatic agent, RY-1180V type high temperature and high pressure dyeing machine
2) Process flow, conditions and prescription
The original yarn enters the factory - loosening - chamfering - loading cage - entering the dye vat - pre-treatment (de-sizing, scouring and bleaching are combined, treated at 100 ℃ for 20 minutes, soaping agent 1g/L to remove oil) - washing - Add the dissolved dyestuffs and auxiliaries to the dyeing tank and invade the dyeing tank in turn—add yarn dyeing (1°C/1min) and heat up to 70°C for level dyeing for 10min—(1°C/1min) heat up to 100°C for level dyeing for 10min—(1°C/1min) ℃/min) raise the temperature to 130℃ and keep for 45-60min—high temperature drainage—washing water—reduction cleaning (treatment at 100℃ for 30min, for dark colors)—washing water—acetic acid neutralization—washing water (with antistatic agent)— Dehydration - drying.
Disperse Dyes (o.w.f.) x
Glacial acetic acid 1.2g/L
Leveling agent 1.2g/L
Restore the cleaning prescription
Glacial acetic acid 1.5g/L
Reduction cleaning agent 1.5g/L
Antistatic agent prescription 1.0g/L
© APANAM 2023