Natural fibers such as cotton, silk and wool have the characteristics of good hygroscopicity and comfortable wearing, and have always been the main fiber varieties that people consume. However, natural fibers are prone to shrinkage, wrinkling, and wrinkles and other defects after washing, which cannot meet the increasingly high demands of people for the beautiful and comfortable fabrics and convenient maintenance. US cotton company researchers from the market survey, more than 85% of consumers are most concerned about the anti-wrinkle durability, washability and wear resistance of clothing, consumers are willing to spend more money to buy anti-wrinkle finished clothing . Therefore, the development of non-iron finishing technology for natural fibers, the production of high-end products, has become one of the direction of joint research and development of the textile and garment industry, wear and care has gradually become an important factor to attract consumers.
There are many names for ironing-free finishing, such as: durable press finishing (PP), non-iron finishing, washing and finishing, and shape memory finishing. Iron-free finishing includes the meaning of “anti-shrinkage anti-wrinkle†or “durable pressingâ€. For products without pleats such as shirts and casual wear, the non-ironing is to “anti-shrinkage and anti-wrinkleâ€, which is reflected in the daily life after washing and drying without washing or just ironing. Requires the appearance of flatness, seam appearance and dimensional stability requirements. For pants products, the non-ironing is “durable pressingâ€, not only anti-shrinkage, but also pleating after washing and drying.
Iron-free finishing technology for cotton fabrics
For the best ironing-free finishing, choose the right finishing formula and baking conditions. Since the fabric of ordinary resin is reduced and the formaldehyde content exceeds the standard, the research on the process of reducing the formaldehyde emission and the development of low formaldehyde finishing agent or formaldehyde-free finishing agent have been a research hotspot.
Finishing methods can be divided into two types: fabric finishing and garment finishing. The fabric finishing has two methods of pre-cure and post-cure. The pre-baked fabric is a flat-panel impregnated resin, and the flat baking is completed by the printing and dyeing factory. The process is simple and easy to obtain, and the flat appearance and the non-ironing effect can be obtained, but it brings certain difficulty to the garment processing, and it is difficult to give the garment some folding and garment shape. Moreover, due to the difference in the dimensional shrinkage of the sewing thread and the cloth during washing, the seam sewn (wrinkle) phenomenon tends to occur. This process is suitable for the finishing of shirt-like garments that are thin fabrics.
The other is a post-baking method, which can be divided into two types: gray cloth padding and clothing impregnation depending on the manner of padding the resin. The former is a cotton fabric soaked in a printing and dyeing factory and dried. The resin cross-linking reaction is left after the garment is sewn and placed in a baking oven. This process is mostly used for clothing finishing such as outerwear and pants which are thicker fabrics. The advantage is that the garment is flatter, the size is more stable, it can be durable and the seam is very flat. The disadvantage is that the finished fabric semi-products are often difficult to control under storage conditions during transport. If the resin crosslinks prematurely, it is slightly wrinkled or smashed, which is difficult to correct later.
The garment is impregnated by soaking the garment in the finishing liquid or after spraying and then drying and baking. After the garment is baked, the cross-linked resin fixes the folded and flat appearance of the garment. After the garment is washed and washed, the fiber strikes the state of trying to return to the cross-linking state. This is the so-called "morphological memory" function. In addition to the advantages of the grey cloth padding method, it can reduce the release of free formaldehyde during garment sewing and affect the working environment of the garment workshop. Generally, the resin can be baked, scalded and baked after the resin is applied, and the steps are continuously performed to avoid the occurrence of quality problems such as long-term residence of the semi-products between the processes and premature crosslinking of the resin.
Super soft finishing and gas phase finishing are resin finishing. After the baking process, the biggest feature is that the trouser line can be kept for a long time after the garment is formed, and the unevenness will not occur at the stitching.
Super soft finishing, also known as SSP (SuperSoftProcess), is characterized by multiple crafts complement each other to achieve a perfect wearing effect. The process is: fabric → bleaching → liquid ammonia treatment → resin finishing → garment → baking. Liquid ammonia is liquid ammonia, which is different from ammonia, not an aqueous solution of ammonia. The viscosity and surface tension of liquid ammonia are much lower than that of water, so liquid ammonia can easily and quickly penetrate into the cotton fiber, which changes the crystal structure of the cotton fiber, which does not damage the fiber and can be quickly and easily released. The combination of resin finishing and liquid ammonia finishing, the two functions complement each other, realizing the anti-wrinkle and non-iron finishing of pure cotton fabric.
Gas phase finishing, also known as VP (VapourProcess), is also baked after sewing into a garment. Unlike the super soft finishing process, the cotton fabric is directly modified with formaldehyde and sulfur dioxide gas. The gas phase method is different from the general resin material, the raw material is cheap, the effect is good, the finished product is soft to the touch, the moisture absorption is good, and the durability is the characteristic. This process is also very suitable for shirts and garments. At present, there are not many gap-type gas phase finishing processes and equipments used in China, which are generally produced in garment garment factories. Ningbo Youngor Company uses this method to produce iron-free shirts.
Another type is AP finishing, AdvancedPerformanceFinishing, which was invented and patented by BASF. In order to overcome the shortcomings of the dry and wet cross-linking process, the process adopts a 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 content (5% to 8%) → baking.
In addition to continuous innovation in the process, some new technologies are also constantly introduced into the ironing-free finishing. For example, partial replacement of sodium hypophosphite with nano-TiO2, in the maleic acid-acrylic acid-butyl acrylate polyacid finishing system, not only reduces the environmental pollution caused by phosphorus-containing compounds, but also has a good ironing effect. The woven fabric of maleic anhydride and maleic anhydride was used to crease the cotton fabric under the action of nano-catalyst SiO2. The wrinkle recovery angle of the fabric was obviously improved, and the breaking strength decreased little. Because nano-materials have special properties such as small particle size, large specific surface area, strong surface activity and good dispersibility, they will play an increasingly important role in the anti-wrinkle finishing of cotton fabrics in the future. In addition, foam finishing, steam flashing technology, radiation graft copolymerization, plasma technology, etc. all provide new ideas for anti-wrinkle finishing of cotton fabrics.
Silk-free finishing technology for silk fabrics
At present, the ironing-free finishing of silk has abandoned the method of chemical finishing but the effect is not obvious. It adopts a combination of physical methods such as changing raw material combination, silk structure and tissue change, and chemical finishing, and is in the process of weaving silk and printing. A series of special processing techniques and high-tech materials have been used to make the ironing-free finishing work very good.
Physical processing method
Using various new fibers such as polyester, acrylic, viscose, Lycra, Tencel, Modal, natural bamboo fiber, soy protein fiber, etc., interlaced, blended, and wrapped with silk, using various fiber properties to complement each other and a variety of The differential properties of fibers are developed to produce multi-fiber composite silk. In this way, the silk ratio in the silk product can be reduced, the grade requirement of the silk used can be reduced, the cost of the product can be reduced, and the anti-shrinkage and anti-wrinkle performance of the product can be improved.
In addition, the fabric structure is complicated, and the novel double-sided structure, varying structure or multi-layer composite structure is adopted, the structure of the silk is changed from the weaving, and the anti-shrinking and ironing finishing in the printing and dyeing is performed, so that the product maintains the silk. Knitted silk is elegant and elegant, soft to the touch, soft in gloss and comfortable in body. It has excellent performances such as machine washability, no wrinkle after washing, superior elasticity and natural recovery.
Chemical finishing method
Conventional resin anti-crease finishing, although the fabric wrinkle elasticity is improved, but the hand feels hard, the color fades, the fabric contains free formaldehyde, and is not suitable for silk fabric.
Silicone elastomer or reactive silicone finishing is very suitable for silk knitwear, which can improve its wrinkle resistance, softness and smoothness, and has no side effects. It is worthy of research and application in the silk industry. The best effect in Japan is the methacrylamide (MAA) grafting. After MAA grafting, the wrinkle resistance and antistatic property of the fabric are improved, and the hygroscopicity and drapability increase with the increase of grafting rate. Almost unchanged. The finishing method can not only graft before the degumming of the raw silk, but also can be grafted after the degumming of the raw silk, and can also be grafted and finished after degumming the fabric. After being processed by grafting, the silk knit fabric is used for outerwear fabrics and even high-grade silk suits. It overcomes the shortcomings of easy shrinkage and wrinkle, and is overly elegant and easy to yellow. It has both a soft and a thick sense of solidity and a unique luster and style.
Through the combination of physics and chemistry, the comprehensive research and development from fiber combination, yarn structure, tissue design to finishing process will be the direction of silk fabrics without ironing.
Iron-free finishing technology for wool fabrics
The non-ironing finishing of wool fabric is mainly aimed at the fluffing property of wool. The fluffing fabric makes the wool fabric easy to be felted during washing, which makes the fabric thicker, harder, smaller in area, fuzzy in surface structure and lower in elasticity, which seriously affects the fabric. Appearance and take-up, which limits the application of wool and the expansion of the market to a certain extent. To this end, wool fabrics must be shrink-proofed.
At present, the anti-shrinking methods of wool can be roughly divided into three categories: subtraction, softening and removing the scales on the surface of the wool, thereby reducing the directional friction effect on the surface of the wool; addition, covering the surface of the fiber with a resinous substance, through cross-linking The fiber directional friction effect is weakened; the addition, subtraction, subtraction and addition method are combined to take advantage of the length and complement each other to achieve anti-shrinkage.
Subtraction and shrinkage prevention
The chlorination treatment method is a relatively mature treatment process. It immerses the wool in a neutral saturated aqueous solution of a strong electrolyte, so that the water is not immersed in the wool, and the wool is immersed in a completely non-expanded state as an eye point, without damage. On the premise of the fibrous matrix, the scales on the surface of the wool are dissolved and removed. This method can achieve the anti-shrinking standard, the fabric feels better, the cost is low, the output is high, but the wool is easy to yellow, the color light changes greatly, and the consistency and uniformity of the treatment are also unfavorable. There are adsorbable organic halogen compounds (AOX), and AOX is harmful to the environment.
Another method is the ozone treatment method. When the wool is in contact with ozone, the wool fibers can be modified to homogenize the layers of the wool surface. As a result, the scales of the wool are no longer opened in the wet state, preventing the felting of the wool fibers. Since it is not processed with chlorine, it is extremely excellent in the environment, but the same as the chlorination treatment, it is easy to cause a decrease in fiber strength and a decrease in elongation at break.
The third method is a protease treatment method, which utilizes the hydrolysis of the peptide bond of the wool fiber by the protease to partially dissolve the scales of the wool, the cell membrane complex, etc., to remove a part of the scale and to remove the scales and corners, thereby making the wool It has a soft, smooth, lustrous effect. The biological enzyme treatment has the characteristics of high efficiency, energy conservation and pollution reduction, and is a relatively environmentally friendly anti-shrinking finishing method.
The fourth method is oxidative-enzyme treatment, which first oxidizes the surface of the wool to make the scales swellable, and then treats with the proteolytic enzyme in the presence of the salt to remove the scales on the surface of the wool. After this treatment, the wool fiber is completely resistant to shrinkage, and the surface is smooth and shiny, and has a soft style. This method is generally used for shrink-proof treatment of tops, loose hairs and yarns, and the damage to wool is smaller than that of chlorination, but the treatment cost is high.
The fifth method is plasma treatment, which utilizes the various effects of highly excited, unstable active particles on the surface of the wool fiber in low temperature radiation, namely etching, roughening, group introduction, cross-linking variants and graft polymerization. The fiber is modified to achieve the purpose of anti-felting. Compared with the conventional method, the disadvantage of plasma treatment is that the equipment investment cost is high, and in addition to corona discharge, other extremely demanding vacuum equipment is required, thereby limiting their application in production. However, plasma treatment has the advantages of no environmental pollution, small damage to fibers, short processing time, and high production efficiency, which will promote the rapid development of the wool shrink-proof finishing industry.
The sixth method is the ultrasonic method, which refers to an elastic mechanical vibration whose frequency (audio or audio) is higher than the normal human hearing range, and its frequency is in the range of 2 x 104 to 2 x 109 Hz. Because the etching effect of ultrasonic waves is destructive to the scales of wool fibers, the ultrasonically treated wool scales become dull and dimmed, thereby reducing the friction effect of the wool fibers and changing the felting properties of the wool fibers to some extent. . Ultrasonic treatment can reduce the dosage of the drug and lower the reaction temperature; the treated wool fiber has good bulkiness, and no entanglement occurs between the wool fibers. However, the processing cost is high and there is noise, and it is rarely used in industrialized production.
Addition shrinkage prevention
Resin finishing is the most typical addition finishing, that is, the surface of the wool fiber is treated with a polymer, the scales on the surface are coated, and the fibers are bonded to each other to give them shrink-proof properties. The resin treatment process is simple, the shrink-proof property is good, and the gloss of the fabric can be improved, but there are two problems: first, the hand feeling of the fabric is significantly affected by the presence of the coating; second, the fastness of the coating may be washed by water, etc. The influence of factors, anti-shrinking durability is not strong.
The second method is biological enzyme finishing, which uses glutamine transaminase to finish the wool fabric, and finally achieves the desired anti-shrinkage effect. The reason why this part is attributed to the addition process is that the mechanism of action is different from the traditional bio-protease hydrolysis process, which utilizes the cross-linking reaction of the effective functional groups inside the wool to achieve the internal or inter-fiber intersection. Together, to achieve the purpose of anti-shrinkage.
The third method is to adopt chitosan treatment method. Since chitosan has certain film-forming property, a film can be formed on the surface of the wool scale to prevent mutual occlusion between adjacent fibers, so that the fiber orientation friction effect is weakened. . More importantly, chitosan can be filled in the angle of the scale or some damage, so that the scales are isolated from each other and lose their effect, so that the forward and reverse friction coefficients are reduced, the directional friction effect is reduced, and the anti-shrinkage effect is achieved.
Addition and subtraction anti-shrinkage treatment
The method of hydrogen peroxide and chitosan firstly treats the surface of the wool fiber with hydrogen peroxide, removes some scales, makes the surface of the wool fiber flat, and increases the absorption performance of the wool on the chitosan solution, and highlights the treatment effect. After the chitosan finishing, the anti-shrinking performance is improved.
Glow Discharge Reaction and Collagen Resin Method, this method is proposed to replace the chlorination shrink-proof finishing process to achieve chlorine-free finishing. The glow reaction process includes plasma etching and surface oxidation. The former functions to remove the fatty acid layer of the wool epidermis and part of the outer skin; the latter acts to add some new anionic groups, such as sulfonates, to the wool epidermis. Carboxylates and the like provide convenience for the subsequent resin coating process. In addition, there are protease and chitosan composite finishing, plasma and chitosan composite finishing, ultrasonic and chitosan composite finishing, etc., all of which are first removed by pretreatment method, and then coated to achieve Very good anti-shrink effect.
Editor in charge: Xu Yuehua
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