Fabric Traders Often Show Off " Milk Silk " What Exactly Is It?

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It is a new milestone for textile materials to use bioengineering methods to implant bovine cheese protein fibers into synthetic fibers with two excellent properties.

Milk protein originated in 1935.

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In 1956, Japanese Toyo textile company produced milk protein filament by blending, copolymerization and grafting with New Zealand milk protein solution and acrylonitrile polymer. It was formally industrialized in 1969, and China began to study it in 1960s.

With the depletion of oil resources and the improvement of human health, the research and application of milk protein fiber will be further deepened and improved.

In this paper, the preparation, structure, properties and application of milk protein fiber are briefly introduced in four aspects.

Preparation of milk protein fiber

The main ingredients of milk are protein, water, lactose, vitamins and ash, among which protein is the basic raw material for making milk protein fiber.

Fiber, mainly because it has the basic conditions of fiber forming polymers: first, the milk protein macromolecule chain, rather than hemoglobin as a spherical protein; second, it has a certain degree of flexibility and intermolecular force, because macromolecules are composed of numerous peptide bonds, and there are hydrogen bonds between macromolecules and other intermolecular forces such as polar groups, such as -SH, -NH2 and so on; third, it has better spinnability; because the protein and water form colloidal solution, after spinning, the water vaporization is removed, and the two molecules will form closer to each other to form hydrogen bonds, so that the polypeptide chains can be arranged parallel or even twisted together, solidify into silk strips, and the breaking strength of the wire can reach 2.5cN/dtex, which can meet the basic requirements of textile fibers. Milk protein can be spun into

The basic raw material of milk protein fiber is milk, which can be divided into three parts: the preparation of casein.

Preparation and draft spinning.

Separation and purification of protein (a casein protein with linear macromolecular structure) by dialysis or dialysis, and then blending with polyacrylonitrile or polyacrylic alcohol (milk protein and polyacrylic alcohol or polyacrylonitrile blended into spinning fluid), crosslinking (crosslinking agent in milk protein and polyacrylic alcohol or polyacrylonitrile solution to make the spinning raw fluid through polymer cross-linking reaction), or graft copolymerization (in the milk protein and polyacrylic alcohol or polyacrylonitrile system to catalyze graft copolymerization of polymer to produce spinning raw liquid), and finally using wet spinning to form fibers, curing, drafting, drying, curling, setting, grading, packaging, etc. the milk contains more than 80% of the moisture. Therefore, it is necessary to dehydrate (less than 60% of water) and then add alkali to make the fat decompose to deoiling and degreasing.

Two, the structure of milk protein fiber

Strictly speaking, only 100% of the fibers made from casein are called milk protein fibers. However, the breaking strength of pure milk protein fibers is relatively low, which limits their application in the textile industry to a certain extent.

At present, the fibers made from bovine cheese protein and polyacrylonitrile or polypropylene alcohol are also called milk protein fibers, and the introduction of polymers enhances their breaking strength.

In some reports, there is also a milk protein / cellulose copolymer based viscose milk protein fiber, called viscose based milk protein fiber, but this is not common.

Milk protein fiber contains 17 kinds of amino acids, which has good skin health function.

Milk protein fiber has a milky white appearance and soft shiny and smooth texture.

The cross section of milk protein fiber can be changed according to requirements. There are many tiny pores on the cross section. There are many irregular grooves and island shaped bump on the longitudinal surface. This is due to the dehydration of fiber surface and the rapid orientation of fibers in spinning process.

Casein components in milk protein fiber are mostly distributed in the amorphous region of fiber, which makes casein protein easily dissolved in high temperature water and dissolves.

The weight loss of polyacrylonitrile milk protein fiber can reach 8% when 80min is treated in 800C.

Three. Properties of milk protein fiber

Milk protein fiber has higher breaking strength than wool, cotton, viscose and silk. The elongation at break is higher than that of cotton fiber, and its moisture absorption is slightly better than cotton fiber and its density is lower than that of cotton fiber.

In addition, the initial modulus and resistance to deformation of milk protein fiber are also good.

The heat resistance of milk protein fiber is slightly worse. When the temperature is 48 degrees, the weight loss starts, and there is a thermal decomposition peak at 92.7 degrees centigrade. When the temperature reaches 149 degrees, the weightlessness can reach 4%. Therefore, it is necessary to pay attention to its heat resistance when processing milk protein fiber or fabric.

Milk protein fiber is relatively poor in electrostatic resistance. It is difficult to eliminate static electricity. Therefore, it is necessary to pay attention to electrostatic factors when finishing spinning or fabric.

The surface friction coefficient of milk protein fiber is relatively small, which is close to silk. The cohesion between fibers is not big, and it is easy to slip, which is not conducive to the smooth process of spinning.

Because milk protein fiber is composed of two kinds of polymers, the process of blending, grafting or copolymerization includes physical and chemical changes. The chemical properties of fibers are the combination of their respective characteristics and comprehensive properties.

Milk protein fiber is heated and melted and has a hard lump after burning.

Milk protein fiber is less alkali resistant than wool. It can not use chlorine bleaching. Its acid resistance is not bad.

Milk protein fiber products can be used more kinds of dyes, such as reactive dyes, weak acid dyes and neutral dyes. The dyeing rate is high and fast, and the dyeing is even.

And wool fibers do not use reactive dyes. After using reactive dyes, milk protein fiber has good fastness to washing and high brightness. It needs full soaping when dyeing deeper colors.

After breaking through ultraviolet radiation, the breaking strength of milk protein fiber is very low.

Therefore, the milk protein fiber has good light fastness.

Milk protein fiber contains a variety of human essential amino acids, which contain 17 kinds of amino acids. It has good skin affinity and skin care function.

Fiber is also rich in natural protein moisturizing factor (because milk protein fiber in the manufacturing process of fat decomposed glycerin, part left in spinning solution), to the human skin moisturizing effect, so that the skin is more delicate and smooth.

Milk protein fiber is not as moth eaten as other protein fibers (wool or silk). It has a natural bactericidal effect and can inhibit E. coli and Staphylococcus aureus. Its antibacterial rate is above 80% and has strong durability.

Milk protein fiber can also produce a large number of functional anion to achieve international standards, so as to purify the air and promote blood circulation, and thus play a bacteriostatic effect to a certain extent.

Milk protein fiber feels soft and smooth like cashmere and silk, and has the characteristics of good moisture absorption and good moisture conductivity, so that it has a high "sleep comfort index".

Besides, underwear made of milk protein fiber also has the function of correcting body shape.

Four. Application of milk protein fiber

Milk protein fiber can be spun, also with

Mao Xianwei, bamboo fiber, soybean fiber, ramie fiber, synthetic fiber and other blended fabrics.

Milk protein fiber fabrics are soft, smooth, hygroscopicity, antibacterial and anti-inflammatory.

The blend of milk protein fiber and cotton fiber can improve fabric softness and skin affinity. It can improve its texture and make thin fabrics such as milk cashmere coat, underwear and outer garment fabrics. It can be blended with hemp fiber to make fabrics such as outer garment, T-shirt, shirt and so on. It can improve the moisture absorption and moisture conductivity of synthetic fibers by blending with synthetic fibers.

Because of its excellent comprehensive performance, milk protein fiber can be woven, knitted, and non-woven. Milk protein fiber can be used in many kinds of clothing, such as fashion, children's underwear, bedding, daily necessities, etc.

Because the milk protein fiber has the soft luster of silk, the fabric made of fine milk protein fiber yarn has excellent drapability, clearer texture, and a sense of elegance and freedom caused by a silk feel. So it is an ideal fabric for making high-grade fabric.

It can make casual clothes for men and women, women's fashion, knitted pullovers, women's shirts, jeans, summer T-shirts, kimono and so on. It can also be blended with other kinds of fibers to make coat and shirt warm clothing fabrics.

The fashions made of milk protein fiber are soft, elegant, light and elegant.

Milk protein fiber textiles can be applied to women's underwear, pajamas, short underwear, sports bra, children's clothing fabrics and other skin clothes.

The clothing made of milk protein fiber is soft, light, smooth, and skin friendly. The underwear made in this winter is warm and spring. It can absorb sweat from exercise, and good air permeability can make you feel cool in summer.

In addition, its fiber products also have the function of sterilizing and moistening the skin, which is called "second skin".

Therefore, milk protein fiber underwear is more comfortable than pure cotton underwear.

Milk protein fiber textiles can be used to make gloves, socks, hats, pantyhose, scarves, bath towels, handkerchiefs, towels and decorative lines.

Because the hands, feet and head are sensitive to cold, delicate skin and easy to breed bacteria, and milk protein fiber fabric has the ability to sterilize and moisten skin and feel soft, so milk protein fiber is the best ideal material choice.

Milk protein fiber can also make bedding. Japanese Toyo textile "Chinon" combines wet conductivity and warmth two to make bedding comfortably, functional and antibacterial.

Five, prospect

It has the advantages of high strength, small shrinkage and good abrasion resistance, and has the advantages of softness, moisture absorption, breathability and skin care. It is a kind of synthetic fiber.

Advantages of a new type of textile fiber.

But there are also two common defects, such as natural protein fiber, alkali resistance, high temperature shrinkage, oxidation bleaching, loss of protein, poor colourness and high price. These defects have limited the diversity of milk protein products to some extent.

With the deepening of the research on milk protein fiber, the fiber modification technology will be more and more excellent, and its fiber will be more and more excellent, and its potential value will be fully developed.