Silk textile antibacterial and mildewproof reasons

Silk is one of the most comfortable and high-grade fabrics for underwear and shirts. Its amino acid residue of protein peptide chain has moderate antibacterial properties and is also a hygienic textile fabric. However, since the silk itself is a protein fiber, it is a good food for mold and bacteria. When the relative humidity is 85 or more, the temperature is 5 to 50 ° C, and the pH is 5 or less, the mold is easily propagated on the silk fiber, and the pH is 6 or more, and the bacteria are most likely to grow. If the silk has a lot of water, or if there is more residual starch, soap, oil or printed silk residue after refining, it will easily breed mold and bacteria under hot and humid conditions, resulting in degradation of protein fiber and strong damage.

There are many kinds of molds that cause mold on silk fabrics, such as Aspergillus niger, Penicillium chrysogenum, Penicillium grisea, Mycobacterium spp., Aspergillus, Cryptobacter, Glycine, Streptomyces, Trichoderma, etc. Ten kinds. When Aspergillus niger is grown on the silk fabric, the spore mass is black, causing the silk fiber to be black, while the Penicillium citrinum is yellow, the green mold is green, and the sporozoite is brown. In the process of metabolism, mold produces glycol, citric acid, oxalic acid, lactic acid, acetic acid, etc., which produces malodor, which causes the fabric temperature to rise, the gloss to decrease, and mildew spots, so the storage, transportation and sale of the dyed fabrics In order to prevent mildew during the pre-storage process, it is necessary to add a bactericidal and anti-fungal agent to prevent the mold from breeding.

There are dozens of bacteria that are easy to breed on silk fibers, such as Staphylococcus aureus, Escherichia coli, Enterobacter, Pseudomonas aeruginosa, Trichophyton, Acne, etc. Some of these bacteria on silk fabrics come from a polluted environment. Some use the process from the body or skin infection. Therefore, after the antibacterial and antifungal agent finishing, the silk textiles can be made more sanitary and hygienic.

Silk textile antibacterial and anti-mildew technology

Process control during scouring and dyeing

In view of the high temperature and high humidity of silk refining and dyeing workshop, the oleic acid soap used for silk refining and certain additives applied on silk during dyeing and finishing, such as plasticizers, oils and pigments, will be under appropriate damp heat conditions. Caused mildew, the anti-mildew measures of the Japanese silk printing and dyeing factory are:

After scouring, dyeing and finishing the silk, the water should be clear.

Keep the scouring and dyeing and finishing workshop operating environment clean and tidy.

Add a certain amount of anti-fungal agent to the silk processing.

The silk after printing and dyeing should be fully dried, dried and then packaged after cooling.

Fiber surface modification

The silk fiber is acetylated and cyanoethylated so that it cannot be a feed for mold. The method of cyanoethylation of silk is to impregnate a 0.1% to 1% aqueous solution of sodium hydroxide or sodium cyanide or to react with acrylonitrile by a gas phase method. This technique uses a chemical reaction to attach an antibacterial group to the silk fiber to obtain a permanent antibacterial effect on the silk fiber. However, this method has higher requirements for antibacterial groups, and mR technology is also more complicated, so the current application is not very extensive.

The chitosan is formulated into a certain concentration of acetic acid solution as an antibacterial finishing agent, and the silk non-woven fabric is finished by a two-dip two-rolling method (rolling ratio of 100). After finishing, the silk non-woven fabric has obvious antibacterial activity against Staphylococcus aureus and Escherichia coli, and has low antibacterial activity against Candida albicans; good washing resistance, no additional cross-linking agent is used, thereby avoiding cross-linking agent The effect of the addition on the feel of the nonwoven fabric. The antibacterial mechanism of chitosan is mainly that the quaternized amino cation in the chitosan molecule can adsorb bacteria, which can bind to the anion on the surface of the bacterial cell wall, hinder the growth and synthesis of the bacteria, and denature it. At the same time, the chitosan molecular chain The cleavage of the glucoside bond prevents the transfer of substances inside and outside the bacterial cell wall, thereby damaging the metabolism, respiration and material transport functions of the bacteria, causing them to lose their living conditions and causing the internal tissues of the bacteria to die and die.

It is reported that the antibacterial conductive silk fiber can be prepared by reacting a copper compound with a sulfur-containing reducing agent, and the preparation process is as follows: a silk fiber-copper compound-a sulfur-containing reducing agent to treat a crystal-antibacterial conductive fiber. X-ray diffraction scanning electron microscopy analysis showed that the surface of the silk fiber covered with a continuous and even distribution of CuS antibacterial conductive layer. The results showed that the treated silk fiber had a bacteriostatic rate of 98% against Escherichia coli, Staphylococcus aureus and Candida albicans, and after 20 washings, the fabric still had a high bacteriostatic rate because A certain amount of copper compound is firmly bound to the silk fiber, and the copper ion concentration on the fiber is 3.13×10-4 mol/g by atomic spectrophotometer; the volume specific resistance PV is decreased from 9.2×109 Ω·cm to 57.6 Ω·cm. Moreover, the washing resistance is good, and the PV increase is not large after 20 washings, and is still of the same order of magnitude. Therefore, the silk fiber prepared by this method not only has excellent antibacterial properties, but also has good electrical conductivity.

The silk fibroin fiber treated with tannic acid is reacted in a solution of silver (I) aqueous solution and zinc (II), copper (II), nickel (II) ammonia complex to prepare metal complexed silk fibroin fiber, Staphylococcus aureus and Klebsiella have a strong bactericidal effect. The preparation method is as follows:

Preparation of silk fibroin fiber: The cockroach was removed from the silkworm fresh sorghum, and the enamel layer was dried in a desiccator and then refined with a 0.5% (mass concentration, the same below) mercerizing soap solution. The concentration of 0.05% Na2CO3 was again released. The solution was immersed for 10 min, taken out and washed with distilled water. After drying, the wax was extracted in diethyl ether for 48 h to obtain pure silk fibroin.

Silk fibroin fiber tannin treatment: silk fibroin and 4.76 tannic acid solution were bathed at a bath ratio of 100:1 at a solution temperature of 70 ° C for 2 h. The silk fibroin fibers were taken out for drying. The adsorption rate of silk fibroin fiber to tannic acid was 25.14%.

Metal complexes were introduced into silk fibroin fibers. Cu(NO3)2·H2O, AgNO3, Ni(NO3)2·6H2O, Zn(NO3)2·6H2O were used to prepare various 0.02M aqueous solutions and 0.02M metal networks. Compound solution. The corresponding KNO3 was added according to the ion concentration of the solution, and the amount of KNO3 corresponding to 0.1 M plus 2 M was added. The tannic acid-treated silk fibroin fibers were immersed in an upper solution having a bath ratio of 100:1 and a temperature of 25 °C. After shaking for 24 hours, it was washed with distilled water and methanol, and then vacuum dried. The experimental results show that the untreated silk fibroin fibers are reacted in an aqueous solution of copper (II), zinc (II) and nickel (II) ammonia complexes to obtain a planar metal silk fibroin complex without antibacterial property; The complexed immobilized fiber impregnated with tannic acid-treated silk fibroin fiber in a low pH silver (I) aqueous solution, showing a low amount of metal ions, but showing a yellow staphylococcus and gram R. serrata has strong bactericidal properties; silk fibroin fibers treated with tannic acid, metal complex fibers prepared in aqueous solutions of copper (II), zinc (II), and nickel (1I) ammonia complexes, Since the formed planar metal tannic acid complex is firmly combined with the silk fibroin fiber, it has strong bactericidal activity against Staphylococcus aureus and Klebsiella. According to the data, the silk fabric treated with tannic acid has a higher absorption capacity for Ag, and forms an abnormally stable silk-tannic acid-Ag complex, which shows good antibacterial property.

The silk fiber is immersed in the dye solution, and the dye molecules are adsorbed on the fiber by intermolecular forces such as hydrogen bonding, dipole force and dispersive force, and then fixed in a solution containing copper (II) ions, and the dye is due to copper (II) ions. Coordination and fixation, after washing and drying, functional silk fibers and fabrics are prepared, which have excellent antibacterial properties. This is the result of synergistic action of dye molecules. After washing 50 times, it still maintains good antibacterial properties and can meet practical requirements.

Cover the silk fiber with a barrier so that the mold cannot come into contact with the fiber

For example, by adding 2% to 3% (by solution volume) of acetic acid to the trimethylol melamine solution to make it an insoluble polymer, and adding 20 formic acid, it can be a formic acid colloid of methylol melamine. After the silk fabric is finished, if it contains 10% to 12% resin, the anti-mildew effect is good.

After the silk is padded with potassium thiocyanate aqueous solution, it is treated with a solution of carbon tetrachloride in 1,2-epoxy-2,3-dichloropropane, followed by washing with carbon tetrachloride, acetone, warm water and drying. Dry, durable and mildew resistant.

The silk anti-mold and antibacterial technology is to prevent the microorganisms such as mold and bacteria from contacting the silk fiber by covering the barrier on the silk fiber, and although the microorganism is not killed, the anti-mildew and antibacterial effect is good.

Anti-mildew and antibacterial measures during storage and storage

Keep the warehouse environment dry, ventilated and clean.

When the silk is put into storage, it is necessary to check whether the bag is damaged, whether it is damp or the moisture content of the packaged box is too high.

Do not stack the silk near the walls, pillars, and ditch, or place it in a leak to prevent the silk from being exposed to direct sunlight.

The warehouse should be disinfected regularly, and the long-term backed silk products should be diligently maintained and turned over.

Anti-mildew and antibacterial measures during household storage

After wearing the silk coat, it is lightly brushed and hung in a ventilated place to eliminate moisture and sweat.

Silk which contains oil soap, starch, etc. is susceptible to mildew and should be washed before storage.

The active period of mold is mainly from April to October every year. Store the container to prevent mold. Place the room where the silk container is stored. The ventilation should be good, the temperature should be low, and the temperature and humidity should be changed little.

If it is suspected that mold is attached to the silk garment, it can be dipped in hot water at around 60 °C, dried, and then stored.

Current status and development trend of silk textile anti-mildew and antibacterial technology

At present, domestic and foreign textile anti-mildew and antibacterial technologies can be roughly divided into two types: (1) antibacterial fiber is first prepared, and then various antibacterial fabrics are produced; (2) the fabric is treated with anti-mold antibacterial agent to obtain anti-proof treatment. Mildew antibacterial properties. In comparison, the fabric obtained by the first method has long-lasting antibacterial effect and good washing durability, but has high technical content, high difficulty, wide field, antibacterial fiber production process is complicated, and antibacterial agent is required to be high, and the second method The processing process is relatively simple, but there are many three wastes in production, and the washing durability and antibacterial effect are poor. Because the second method is easy to process and has a wide range of antibacterial agents to choose from, textiles can be obtained by post-finishing methods, whether raw fiber, yarn or fabric, or even ready-to-wear. In the fabric, most of the finishing and processing. However, according to the development trend, it is necessary to develop antibacterial fiber in the future. For natural fibers, since it is difficult to obtain an antibacterial effect by means of fiber modification, textiles made of natural fibers are still mainly treated in the future. Therefore, silk textiles are mainly treated with anti-mold antibacterial agents for post-treatment processing to obtain anti-mildew and antibacterial properties. At present, most of the commercially available anti-mold antibacterial agents have problems such as poor antibacterial broad spectrum, poor washing resistance, and unreliable safety. The future development trend should be: the use of high-prevention mold antibacterial agent to treat silk fabrics, such as natural anti-mold antibacterial agents (such as chitosan, Luohanbai, mugwort, leek, etc.) to deal with silk fabrics; improve anti-mildew and antibacterial The effect of washing durability, durability and broad spectrum; development in a multi-functional direction, such as anti-mildew antibacterial processing and dyeing, flame retardant, soft finishing, resin finishing, waterproof and moisture-permeable finishing, anti-fouling, easy to clean, UV-resistant finishing The combination of equal parts enhances the added value and market competitiveness of silk and caters to the needs of consumers.

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