In 1926, the British company TBL applied for the first patented technology for anti-wrinkle and anti-shrinkage finishing of fabrics. Today, it has been more than 16 years since the advent of anti-wrinkle and shape-keeping shirts. The no-iron finishing of fabrics has also gone through five stages: anti-shrinkage and anti-wrinkle finishing, washable and wearable finishing, durable press finishing, low-formaldehyde finishing, and green finishing. The anti-wrinkle properties of 100% cotton fabrics have also reached level 4, and they still have good shape retention after being washed many times.
For cotton shirts, no ironing is to improve the elasticity, wrinkle recovery angle and dimensional stability of cotton fabrics sex.
At present, dyeing and finishing companies at home and abroad commonly use resin cross-linking finishing, that is, using resin etherification products as cross-linking agents, in acidic catalysts and appropriate baking At high temperature, network cross-linking of cellulose fibers is formed, thereby improving the wrinkle resilience and dimensional stability of the fabric, and giving the fabric good anti-wrinkle and easy-iron effects.
To develop a no-iron anti-wrinkle shirt, we can start with comprehensive consideration and research from the selection of raw materials and yarns, the coordination of the weaving process, the no-iron pre-treatment, the no-iron finishing, and garment making. .
For example, in 2003, Japan’s Nisshinbo Company and Itochu Company jointly developed a 100% cotton non-iron anti-wrinkle shirt. It embeds extremely tiny resin particles into the cotton fabric to prevent the fabric from wrinkling, and uses Hong Kong clothing manufacturer TAL Clothing Co., Ltd.’s anti-wrinkle sewing technology;
In addition, Lu Thai Textile Co., Ltd. (referred to as Lu Thai) selected Dow Chemical Company’s XLATM polyolefin-based elastic fiber for its In cotton-containing no-iron shirts, to increase the wrinkle resistance of the shirt; in addition, Tianjin Tiange Textile Co., Ltd. uses liquid ammonia + moisture cross-linking process to carry out no-iron finishing of yarn-dyed cotton.
Most of the no-iron anti-wrinkle shirts on the market today will have their anti-wrinkle properties greatly reduced after being washed several times. However, Nisshinbo Textile Co., Ltd. has improved the wrinkle resistance of 100% cotton fabric to level 4.0. After multiple washings, the shape retention of the shirt is still good. The principle is as shown in the figure. The no-iron finishing agent evenly penetrates deep into the fabric and yarn, and successfully adheres and cross-links into a network. Therefore, even after multiple washings, the no-iron performance of the shirt can still be better. Play well.
1. Liquid ammonia + tide cross-linking process
According to statistics, there are currently only about 10 liquid ammonia + liquid ammonia + The total production capacity of tide cross-linking production equipment is about 70 million meters. The liquid ammonia tide cross-linking process has wide adaptability to almost all cellulose fibers, regenerated cellulose fibers and polyester/cotton fabrics.
Liquid ammonia finishing, also known as SSP finishing, is a relatively advanced technology in today’s international post-finishing technology for natural fibers such as cotton and linen. The patented technology is mainly in the hands of developed countries such as Europe, the United States, and Japan, and is used by Japan. The textile industry regards it as a key technology to maintain the domestic production base.
The surface physical state of liquid ammonia is the same as water and easy to flow, but its viscosity and surface tension are relatively low and it is extremely permeable. When cotton, linen and other fibers are wetted in liquid ammonia at minus 33°C, the liquid ammonia can instantly penetrate into the fiber, causing the outer shell of cotton, linen and other fibers to shrink, the inner core to expand, and the cross-section changes from flat to round, radially The distortion becomes smaller and the surface becomes smoother. Due to the change in the crystal structure of the fiber, the internal stress is eliminated and no longer distorted, thereby improving the tensile strength and tear strength, and it can still maintain a good feel even after repeated washing.
Pure cotton fabrics have the following characteristics after being treated with liquid ammonia:
The fabric has enhanced hygroscopicity, softer and more elastic feel, long-lasting effect, brighter gloss, and greatly reduced shrinkage. The anti-wrinkle performance is greatly enhanced and has a certain no-iron effect. Tide cross-linking finishing is one of the process technologies of resin cross-linking finishing, which is commonly used to produce pure cotton high-end clothing fabrics.
That is, after the fabric is padded with resin, it is first dried to a specific moisture content, and then stacked and reacted at a temperature of 25 to 35°C.
Moisture cross-linking is a low-temperature reaction, and the cross-linking time is long (usually 24 hours). The moisture regain of cross-linking is equivalent to the moisture regain of the fabric when worn, so the anti-wrinkle performance is excellent. Liquid ammonia + tide cross-linking finishing technology combines two production processes, that is, liquid ammonia finishing is followed by tide cross-linking finishing.
Its characteristics are that it can make the finished fabric achieve a very good anti-wrinkle and iron-free effect, with good resilience and flatness, and little strong damage. The anti-wrinkle level of the fabric can reach 3.5~4.0. , to meet the requirements of high-end fabrics.
The main process flow is as follows:
Liquid ammonia finishing process flow:
Fabric→drying→cooling→liquid ammonia padding→reaction chamber→ Steaming chamber → Neutralization and water washing → Post-processing.
Tide cross-linking process:
Fabric→resin padding→drying→insulation and stacking→neutralization and washing→post-processing.
2. Mild baking process
The mild baking process was originally an improved process of pre-baked durable press (PP) finishing. It solves the problem of cross-linking of fibers in a dry state during high-temperature baking in traditional processes, thereby improving the distribution of cross-links and improving wet wrinkle resistance.
The main principle is to use a stronger catalyst to complete cross-linking at a lower temperature (generally 100 to 120°C, not exceeding 130°C).
At present, this process has been successfully applied to high-end thin cotton non-iron shirt fabrics and bedding. Mild roastingThe cross-linking process is considered to be the most likely candidate to replace the tide cross-linking process. Basf has applied for a patent for “Advanced
PerformanceFinishing” (referred to as AP finishing process).
This process adopts the simple method of dry cross-linking to achieve the same advanced finishing effect as the wet cross-linking method.
The process flow is:
Padding resin → drying to normal moisture regain (5% ~ 8%) → baking.
The mild baking process and equipment are the same as the traditional rolling baking process, only the process technical parameters are different.
In addition to continuous innovation in technology, some new technologies are also constantly introduced into iron-free finishing. Some researchers have proposed using a mixed finishing solution of citric acid and maleic anhydride to perform anti-wrinkle finishing on pure cotton fabrics under the action of nanocatalyst SiO2. After finishing, the wrinkle recovery angle of the fabric is significantly increased, and the breaking strength is not significantly reduced.
Because nanomaterials have special properties such as small particles, large specific surface area, strong surface activity, and good dispersion, they will play an increasingly important role in the anti-wrinkle finishing of cotton fabrics in the future.
In addition, foam finishing, steam flash explosion technology, radiation graft copolymerization, plasma technology, etc. have provided new ideas for anti-wrinkle finishing of cotton fabrics. </p
