Liu Xue Shandong Textile Research Institute

【Abstract】 This paper discusses the status quo of finishing agents used in various anti-microbial finishing of textiles, introduces the synthetic process route and its use characteristics, and expounds the development prospects.

Key words: textile, antibacterial, antibacterial, finishing

introduction

Microorganisms are a general term for low-lying organisms that are small in size and simple in structure, and generally include viruses, viroids, rickettsia, bacteria, actinomycetes, fungi, small algae, and protozoa. The microorganisms closely related to the antimicrobial finishing of textiles are bacteria, molds (septic fungi), yeasts and actinomycetes.

Microorganisms are widely distributed in nature, and microorganisms are present in air, soil, rivers, oceans and natural objects. Organic substances or materials containing organic substances are themselves nutrient sources that are easily used by microorganisms. Once environmental conditions are appropriate, microorganisms will rapidly grow and multiply, destroying the material structure of materials and deteriorating and deteriorating them. Excessive reproduction of microorganisms on textiles, in addition to causing damage to the appearance and performance of the textile itself, can also cause infection and injury to the user.

The use of biocides to control microbial contamination and damage is an effective and widely used method. There are many chemicals or bactericides that can give textiles inhibition of microbial growth and killing of microorganisms, but considering the toxicity of these chemicals and their impact on the environment, as well as the characteristics of textiles, finishing process requirements and finishing products The end use, etc., can be limited in selectivity. Among the large number of fungicides, only a few can be used for antimicrobial finishing of textiles. Usually we refer to such fungicides as antibacterial finishes, sanitizers and antimicrobial finishes.

Since the 1980s, in the developed countries such as Japan, the United States, and Europe, antibacterial and deodorant and other antimicrobial finishing textiles such as odor-resistant socks and anti-bacterial and odor-resistant carpets have begun to be marketed. China also started research and development during this period and gradually realized industrial production. At present, due to the opening of the market and the lack of relevant laws, the chemicals or finishing agents used for such sorting are lack of transparency and are relatively chaotic and disorderly, which should be paid attention to by the industry.

The current research and development hotspots mainly focus on the application of natural antimicrobial materials such as chitosan, polymer cationic polymers and nanomaterials, and research on renewable antibacterial finishing technology.

Introduction of commonly used antibacterial agents and their synthetic processes

Any textile finishing technique that inhibits or kills microorganisms can be referred to precisely as Antimicrobial Finishing, but it is often subdivided into three parts.

Rot-proof finishes are anti-microbial finishings that protect textile materials from long-term or short-term protection from deterioration. They usually prevent the growth of molds from damage to textiles and are used in the processing of outdoor textiles such as tents.

Hygene finishes mainly involves the control of harmful bacteria and infections. It is mainly used for the finishing of textiles or other skin-contacting textiles, including the control of dust mites, that is, mites.

Aesthetic finishes are mainly used to control the occurrence of odor and prevent color change caused by bacteria.

The three parts are only relatively speaking. Some anti-microbial finishing products can achieve the above three finishing purposes at the same time. For example, the deodorant cotton socks can prevent the deterioration of the cotton fiber, control the growth of the ankle fungus and inhibit the generation of odor.

·1 commonly used antimicrobial finishing agent

In theory, the fungicide used in textile finishing is called an antimicrobial finishing agent. The effect of the fungicide on the microorganisms is that the microorganisms are actually killed, and some are only inhibited due to the inhibition of a certain process of the biological activity of the microorganisms, so there is a bactericidal and bacteriostatic effect. However, the bactericidal and bacteriostatic effects are only relatively related, and it is closely related to the nature of the bactericide, the concentration of use and the duration of action. Therefore, sometimes the same fungicide is bacteriostatic at low concentrations, but bactericidal at higher concentrations. The finishing of textiles must meet the requirements of textiles' own performance, processing technology and end use. Therefore, the ideal antimicrobial finishing agent should have the following characteristics;

Broad spectrum antibacterial, effective against bacteria and fungi.

Long-lasting and effective, durable washing continues to be effective.

Safe to use, non-toxic to humans at the concentration used.

Colorless and tasteless.

Lower cost and effective at low concentrations.

Rain-resistant, weather-resistant, and sun-resistant.

No adverse effects on the hand and other physical properties of the fabric.

It is compatible with water repellents and flame retardants, dyes and other textile chemicals.

Does not accelerate or catalyze other deterioration problems.

It can be applied using conventional textile dyeing and finishing equipment.

Can withstand processing conditions and temperatures.

No environmental problems.

In fact, so far, no bactericide has fully met all of these characteristics, and there are more or less certain weaknesses. Some antibacterial agents are very effective against bacteria, but they are not effective against fungi. Some are just the opposite; some are not washable; some have certain harm to people and the environment. Therefore, it is reasonable to appropriately select an antibacterial agent depending on the end use of the textile. Antimicrobial agents for textiles intended for contact with the skin and their finishing products must be safe, completely non-toxic and non-irritating to humans, and the antimicrobial finishes used in frequently used products must also be non-sensitizing. This regulation in developed countries such as Europe and the United States is quite strict, and there are corresponding legal and regulatory agencies. The hazard is obvious by the wrong choice and the use of antimicrobial finishes and their processed products.

Introduced below are several antimicrobial finishes currently in large use.

·1·1 aromatic halogen compound

Representative of this is the first Triclosan developed by Ciba, namely 2,4,4'-trichloro-2'-hydroxydiphenyl ether or 5-chloro-(2,4-dichlorophenoxy)phenol. The product names are: Yujiexin DP300, CH-3565, Lexol 300, Irgasan DP300, antibacterial agent SFR-l, UMS-406, CHA, etc.

Synthesis

The literature shows that Triclosan can be prepared by the following six routes: (1) A route prepared by condensation, nitro reduction and diazotization hydrolysis using 2,5-dichloronitrobenzene and 2,4-dichlorophenol as raw materials. (2) A route prepared by condensation, dealkylation, nitro reduction and Sangmeyer reaction using 3,4-dichloronitrobenzene and p-chloroalkoxyphenol as raw materials. (3) A route prepared by condensation, chlorination or dealkylation using o-methoxyphenol and bromobenzene as raw materials. (4) A route prepared by a condensation, chlorination or dealkylation reaction using o-alkoxychlorobenzene and a halogenated phenol (salt) as raw materials. (5) A route prepared by decondensation, decarboxylation, and dealkylation using 2-chlorobenzoic acid and 2-alkoxyphenol as raw materials. (6) A route prepared by condensing, isopropyl (isopropenyl) oxidation, and acid decomposition reaction using isopropyl (isopropenyl) phenol and halogenated benzene as raw materials. Among them, (4), (2), (3), and (6) are the most valuable.

A route prepared by subjecting 2,5-dichloronitrobenzene and 2,4-dichlorophenol as raw materials through basic condensation, nitro reduction and diazotization hydrolysis. An example is as follows: 38g of 2,4-dichlorophenol, 15.2g of Na0H and 39g of 2,5-dichloronitrobenzene are added to 200ml of butanol for boiling for 18h, while water is distilled off, and 2g of activated carbon and ethanol are added after the reaction. 200ml, heated and boiled for 1h, then filtered hot, the filtrate was cooled and precipitated, and filtered to obtain 58 g of 2,4,4'-trichloro-2'-nitrodiphenyl ether in a yield of 90%.

The product is similar in performance to disperse dyes and is easy to make into dispersions or emulsions. It is easy to use. However, the safety of this product has caused widespread doubts. Although it is non-toxic and non-irritating to the skin, it produces three toxic chlorinated derivatives with chlorine bleach and produces a carcinogen under the action of heat and ultraviolet light (tetrachlorodioxa It is harmful to humans in addition to cyclohexane. In addition, the synthesis is likely to produce by-products of Dioxins and Dibenzofurans. Although the content is very low, it is very toxic. It has been reported that Japan has banned its application in clothing and textiles that are in contact with skin. However, the product can be used for antibacterial and anti-mite finishing, such as the processing and processing of products such as mattresses and mattresses that are not directly in contact with the human body.

·1·2 胍 salt

Among the biocides of medical double-twist structure, products with low water solubility and adsorption properties to fibers can be used for antibacterial and deodorant finishing of textiles, and the effect is also good. For example, chlorhexidine (chlorhexidine), which is widely used in medical treatment, i.e., 1,1'-hexamethylenebis[5-(4-chlorophenyl)] biguanide hydrochloride, is highly effective in killing bacteria.

In the 1980s, ICI developed the antibacterial and deodorant finishing of the double-twist structure antibacterial agent, and set up Zeneca to be introduced to the market. In July 1999, it was changed to operate by Avecia, and the original product name: Reputex 20 was still used. Its active ingredient is polyhexamethylene biguanide hydrochloride (PHMB), which is a typical representative of biguanide antibacterial agents. Similar products include: Vantocil IB, Vantocil TC, and AM-020. The chemical structure is as follows:

Synthesis of polyhexamethylene biguanide hydrochloride (PHMB)

The synthesis route is a reaction of heating the copper salt or the zinc salt of hexamethylenediamine and dicyandiamide at 60 ° C, reducing the pH from 11 to 6.8-7 by chlorine dioxide, cooling and filtering, and preparing the methylene diamine first. The dicyanate is treated with diamine and 36% hydrochloric acid, then heated to 150-155 ° C, and stirred for 4 hours to obtain a product.

among them

The biguanide finishing agent can only be used for cellulose fiber. The content of cellulose fiber in the blended fabric should not be less than 30%, and its safety is recognized by the US FDA and EPA. The problem is that the price of chlorhexidine is higher, and the second is a biguanide antibacterial agent, which is usually not resistant to chlorine bleaching and sun exposure. However, if Avecia has solved this problem and obtained relevant patents, it is simply treated with a specific strong organic acid or a water-soluble salt of the strong organic acid after finishing, which not only greatly improves the washing resistance and chlorine resistance. Drifting also inhibits the problem of chlorine absorption and yellowing [7].

·1·3 Silicone Quaternary Ammonium Salt

Molecular formula

Wherein R is a methyl group, when X is chlorine, it is DC5700, AEM5700, and Japan's Shin-Etsu is Polon MF5O, wherein R is also a methyl group, X is a bromine, and AM101 is an ethyl group and X is a chlorine.

It is typically represented by trimethoxysilyl dimethyl octadecyl ammonium chloride, DC-5700, which was first developed by Dow Corning of the United States. It is now operated by AEGIS, a division of Dow Corning. The name is AEM5700. From the perspective of its molecular structure, this is probably the only one. It is an antibacterial agent tailored for the antimicrobial finishing of textiles. It has two parts: active cross-linking and active sterilization. Wide range, suitable for all kinds of fiber materials, broad-spectrum antibacterial, and solve the problem that most bactericides are not resistant to washing. The product can also be used for antibacterial and anti-mite finishing. Under semi-natural conditions, the experimental evaluation (PPCBelgium) was carried out for 6 weeks. The mats prepared by DC-5700 were removed compared with the unfinished mats. Dust mites

. This product is a non-dissolving antibacterial agent and does not induce the development of resistant bacteria. Dow Corning began research and development in the early 1970s, and it took decades to invest huge amounts of money to confirm its safety. It will not be repeated here. The problems of such products are as follows: First, for high whiteness bleaching products, such as pure cotton and bleached knitted fabrics, the whiteness has a certain influence; second, the pro-high hydrophilic products such as towels The water content is reduced; in addition, it is not resistant to high temperatures.

In the early 1980s, when our institute cooperated with Shanda to develop AM-101, the methanol solvent was changed to ethanol, and the trimethoxy group was changed to triethoxy. It was worried that methanol might harm the operators of the dyeing and finishing factory. The difference in use is mainly the heat treatment temperature at the time of finishing, which is slightly higher than the former.

Some people have used quaternization of aminosilicone oil as an antibacterial agent. I don't think it should be a product of this kind. The disadvantages are obvious, dissolution and washability are relatively poor.

Synthetic route of organosilicon quaternary ammonium salt: mainly prepared by quaternization reaction of chloropropyltrialkoxysilane coupling agent and octadecyldimethylamine with alcohol as solvent.

Among them, in DC5700, AEM5700 and other products, R is methyl and X is chlorine; Polon MF5O wherein R is also methyl, but X is bromine, and both are 42% methanol solution; domestic STU-AM101, AM- 101 is an ethanol solution in which R is an ethyl group, X is chlorine, and the content is 40%.

·1·4 silver particle application

Silver particles appearing as silver zeolite complex or metallic silver are typical representatives of inorganic antibacterial agents, characterized by good heat resistance, broad-spectrum antibacterial, good durability, and no drug-resistant bacteria, but the problem is easy Discoloration, manufacturing difficulty, and suitable finishing process is limited. Most of the blending methods are added to synthetic fiber polymers to prepare antimicrobial synthetic fibers. In the finishing, it can be applied to the coating process to improve the anti-corrosion and anti-mildew properties of the coating material. The sulfonic acid silver method of Rihua Company is used for the antimicrobial finishing of cationic dyeable polyester fabrics. Specifically, the cationic dyeable polyester fabric having a sulfonic acid group is immersed in a 0.002% silver nitrate solution, and then boiled under stirring. After 20 minutes, it is taken out and cooled, washed thoroughly, and dried. The dyeable residue (SO3-) of the polyester fiber is combined with the silver ion, and the silver sulfonate antibacterial agent is fixed on the fiber to obtain an antibacterial fiber or fabric.

·1·5 Benzoimidazole Carbamate (BCM)

The pure product is a colorless and odorless crystal with a solubility in water of 8 mg/kg (pH 7), soluble in organic acids such as inorganic acids and acetic acid, and slowly decomposed in an alkaline solution. Good thermal stability and chemical stability. The acute oral LD50 of rats is greater than 15000mg/kg, which is a low toxicity fungicide. However, since BCM is irritating to the skin, it should not be used as a finishing agent for textiles in contact with the skin, and is mainly used as a mildewproof or antiseptic finishing process for fabrics, and can be used in combination with other fungicides. When it is used, it is usually ground and refined to make it into a slurry. The dosage is generally 0.25-0.5%, the amount of binder is 3-5%, and the process is padding

Synthesis of anti-mold agent BCM: Mix methyl cyanocarbamate and o-phenylenediamine in a certain ratio. At pH 6.0, heat to 100 ° C, and react for 1.5 h to obtain benzimidazolyl carbamate (BCM) ). The reaction yield is mainly affected by the concentration of methyl cyanamide. When the concentration of methyl cyanamide in the reaction system is between 170 and 180 g/L, the reaction yield can reach a maximum value of 90% to 95%.

·2 other kinds of antibacterial agents

Microencapsulated products of various specific plant extracts. More representative is Japan's Daiwa Chemical's products, which have relatively good results, but are expensive [10].

Introduction to several aspects of research and development

·1 Research and development of chitosan and other natural antibacterial agents

·1·1 Research on the application of chitosan and its derivatives, the main purpose is to solve the problem of durability of chitosan and solve the water solubility, improve the antibacterial performance, etc., mostly using BTCA, CA and NMA and other finishing agents to shell Glycans are interlinked with cellulose fibers to improve their durability, and the effect is obvious. A more interesting derivative of chitosan is N-(2-hydroxy)propyl-3-trimethyldeacetylated chitosan chloride (HTCC), which is synthesized as follows.

The use of chitosan and glycidyl trimethylammonium chloride to prepare HTCC, using the high antibacterial properties of HTCC, using NMA or other resins and adhesives to improve the washability [1,2].

· 2 nano materials and technology applications

In recent years, the development of antimicrobial materials, especially nano-scale powder inorganic materials, has attracted attention due to the photooxidation catalysis of nanomaterials. In the textile industry, the blending process is mostly used to make functional fibers, and the finishing method is limited to coating or fixing with a binder. But nanotechnology is still in its infancy, and there is a lot of misunderstanding and uncertainty. Especially is nanotechnology as safe as people think? Some professionals now have a view on the possible hidden dangers of nanotechnology. Because it is tiny, it can be pervasive, including the human brain. A research report commissioned by the British government pointed out that the nanoparticles and fibers produced by scientists, because they are so small that they are invisible to the naked eye, pose a threat to health and environmental protection. Accordingly, some cosmetics in the US market are out of The reason was banned, and the relevant departments also stopped research work that deliberately added nanomaterials to the living environment. The report also strongly warns that because the products made with nanotechnology are extremely small in size, unpredictable in nature, and some are even toxic. The head of the research team, Ann Dowling, pointed out that the benefits and risks of nanotechnology are now infinitely exaggerated, but there are concerns about it. She said: "There is evidence that nanoparticles are more toxic than the prototype materials, and we are currently researching them." Although there is no need to panic about nanometers, careful observation and demonstration should be carried out before the widespread use of nanotechnology. In particular, the impact of this technology on people and the environment.

·3 durable, renewable antibacterial finishing

Since most American households use chlorine-containing detergents, some antibacterial textiles lose their activity after chlorine bleaching. The halogen amine compound is characterized in that its formation reaction is reversible, so the heterocyclic compound Anti-l (MDMH)-hydantoin derivative which is a halogen amine precursor is selected, which has a potential biocidal group and is grafted to On cellulose. When washed with a chlorine-containing detergent, the group is converted to biocidal

Sexual haloamine structure. This provides a convenient way to activate and regenerate the biocidal function.

It is mainly regenerated by the bactericidal activity of the haloamine structure and the above reversible reaction. When the structure I is washed with chlorine bleach or with an effective chlorine detergent, it will be activated into a bactericidal activity structure II, and the structure II is inactivated after sterilization. I[5][6].

·4 new polymeric cationic compounds for antimicrobial finishing

Among them, the most famous one is polyhexamethylene hydrazine (PHMG), the trade name is AKWATON, AM-025, etc. It is characterized by large molecular weight, the degree of polymerization is said to be up to about 100, and the safety is high. Strong directness and easy to use. The product is currently in production in Russia, South Korea and China. We are conducting a comprehensive research assessment to understand its characteristics and its differences with PHMB.

Most of its synthetic routes are achieved by polycondensation of guanidine hydrochloride with 1,6-hexanediamine [11].

Several viewpoints of using finishing agents

· 1 Clear the main ingredients of the finishing agent to avoid containing harmful substances or other prohibited ingredients.

·2 For the anti-microbial processing of textiles such as clothing, it is not possible to emphasize the anti-microbial effect on one side. The selected finishing agent should be effective, safe and durable. Controlling the microbes in a certain amount, inhibiting the excessive reproduction of microorganisms, is more in line with the micro-ecological balance of the human skin surface than the complete killing, and is more beneficial to human health.

·3 Depending on the end use of the processed textile, it is more realistic to use a suitable antimicrobial finish.

·4 The use of existing finishing agents can increase the spectrum of antibacterial bacteria and reduce the risk of producing resistant strains.

Outlook on development prospects

· The development of new antibacterial agents is very risky and should be carried out with caution, not to mention the cost of research and development. If the products are exported, they must pass the certification of the host country. In the case of the European Union, according to the BPD regulations implemented in 2000, before a new antibacterial agent was introduced to the market, the certification cost of the authority was as high as 2 million euros, and the single test cost was 100,000 euros. The cost was huge.

· 2 For nanotechnology for antimicrobial finishing, I believe that there are too many unknown and uncertain things at present, especially the research on safety should be strengthened, and there is still a certain distance from marketization.

·3 Strengthen the experimental research on the mixing and use of existing finishing agents, and make full use of existing resources.

[China Antibacterial Fabric Network ]