What kinds of bactericidal preservatives are added to household detergents

Fungicides can be divided into synthetic fungicides and natural fungicides according to the source, and can be divided into halogen series, oxygen series, aldehydes, phenols, quaternary ammonium salts, guanidines, Chinese herbal medicine extracts, etc. according to their chemical composition. In daily chemical detergent products, the fungicides are mainly Staphylococcus aureus, Escherichia coli and Candida albicans.

1. Halogen

Halogen fungicides include chlorine, bromine and iodine. Since halogen elements have strong oxidizing properties, compounds containing these elements usually have strong bactericidal and bleaching properties.

1) Chlorine-containing fungicides

Chlorine-containing bactericides have strong bactericidal power and can kill various microorganisms including bacterial spores. In addition, chlorine-containing bactericides also have the advantages of wide sources and low cost, but chlorine-containing bactericides have strong irritation and are sensitive to PH, limiting its range of use. Chlorine-containing bactericides commonly used in household detergents mainly include sodium hypochlorite and sodium dichloroisocyanurate.

Sodium hypochlorite produced by industry has an effective chlorine content of about 10%~20%. It is a strong oxidant and has strong sterilization and bleaching effects, but it has a corrosive effect on metals and is easy to decompose. Generally, Na2CO3 needs to be added to liquid detergents. Or Na2SiO3 to enhance the stability of sodium hypochlorite. In terms of compatibility, sodium hypochlorite is harmful to some dyes, and will interact with essences, enzymes and fluorescent whitening agents, so it is often used alone in disinfectants and bleaching solutions.

Sodium dichloroisocyanurate, also known as Youchlorjing, is a broad-spectrum fungicide, its dry powder is stable in storage, and its aqueous solution has poor stability. Sodium dichloroisocyanurate has no cumulative toxicity and mutagenic effect, good safety, and is suitable for use in household detergents. In terms of compatibility, substances such as fatty acid diethanolamide, alkylphenol polyoxyethylene ether, borax and soda ash can decompose sodium dichloroisocyanurate, while sodium alkylbenzenesulfonate, sodium fatty alcohol ether sulfate, fatty alcohol Polyoxyethylene ether, sodium sulfate, sodium chloride, etc. will strengthen the stability of sodium dichloroisocyanurate.

2) Brominated fungicides

Commonly used bromine-containing fungicides mainly include bromochlorohydantoin and dibromohydantoin, which are environmentally friendly after use. Compared with chlorine-containing fungicides, bromine-containing fungicides have a better ability to kill microorganisms in an alkaline environment, and the degradation rate is faster, but because bromine-containing fungicides are expensive, they are mostly used in hospitals.

3) Iodine-containing fungicides

Iodine-containing bactericides, such as elemental iodine and povidone iodine, are widely used in the field of medicine and health. In recent years, they have also been used in the field of detergents. Elemental iodine has good permeability and can quickly penetrate the cell wall to denature proteins and lose their activity. Studies have shown that by compounding 0.5% iodine with fatty alcohol polyoxyethylene ether sodium sulfate (AES) and other 12 surfactants, the obtained iodine-containing antibacterial detergent can obtain satisfactory decontamination and sterilization effects.

2. Peroxides

When peroxide fungicides are dissolved in water, they will dissociate free radicals with high redox potential, thereby destroying the permeability barrier of microorganisms or proteins, DNA, etc., and eventually leading to the death of microorganisms.

1) Liquid peroxide

Liquid peroxides mainly include hydrogen peroxide and peracetic acid, which are highly corrosive and have a bleaching effect on fabrics. At present, hydrogen peroxide is mainly used in the formulation of color bleaching liquid. Some studies have tried to apply hydrogen peroxide to dishwashing detergents. However, heavy metals, alkaline environments, and light can cause the decomposition of hydrogen peroxide, so it is compatible when adding it to the formula. There are many taboos.

2) Solid peroxide

Solid sodium perborate and sodium percarbonate are mostly used in powdered detergent formulations. Among them, sodium perborate and sodium percarbonate have a high oxygen release temperature, and the bactericidal effect can only be exerted when the temperature reaches above 40°C. And the stability of sodium percarbonate etc. is also relatively poor. Based on this, this type of fungicide is mainly used in formulas such as washing machine tank cleaners and pipe dredging agents.

3) Stabilized chlorine dioxide

Chlorine dioxide is listed by the World Health Organization as a high-efficiency and safe fungicide of A1 level. It is a yellow-green gas at room temperature, has high chemical activity, and its disinfection effect is 5 times that of chlorine.  The compounded stable chlorine dioxide with AES, 6501, TX-10, and sodium dodecylbenzenesulfonate to make a liquid detergent, and tested the decontamination ability, foaming power, and bactericidal properties of the product, the results show that after adding chlorine dioxide, the detergency of the formula is higher than that of commercially available detergents, and chlorine dioxide and surfactants have a "synergistic effect", which can enhance the cleaning effect. In addition, chlorine dioxide has a certain viscosity-increasing property, but when its concentration is high, the foaming power of the product decreases.

3. Guanidines

Fungicides are mainly divided into biguanide fungicides and monoguanide fungicides, of which biguanide fungicides include chlorhexidine and its derivatives, polyhexamethylene biguanide salt, polyaminopropyl biguanide, etc.; monoguanide fungicides It is mainly polyhexamethylene monoguanidine, including hydrochloride, stearate, propionate, etc. Studies have shown that the bactericidal effect of hydrochloride is stronger than that of other types.

Chlorhexidine, also known as chlorhexidine, mainly has two types of acetate and gluconate, and has broad-spectrum antibacterial effect. Bacteria, but chlorhexidine cannot kill bacterial spores and fungi, and is often used as a preservative in hand sanitizer, toothpaste, and skin care products in the field of daily chemicals.

Polyhexamethyleneguanidine hydrochloride is a low-toxic substance, has no corrosion to metals, and has no bleaching effect on fabrics. This type of fungicide has good water solubility and thermal stability, low foam and easy washing, and is not sensitive to pH. Compared with chlorine-containing bactericides or peroxide bactericides, polyhexamethyleneguanidine bactericides are less toxic, less irritating, and safer, and are widely used in household detergents.

In terms of compatibility, since guanidine fungicides are cationic fungicides, compatibility with soaps and anionic surfactants should be avoided when using them. In addition, some nonionic surfactants will also affect their bactericidal power. At the same time, polyhexamethyleneguanidine in a single formula is a low-efficiency fungicide, and should be used in conjunction with other fungicides in formulas that require high-intensity or long-term disinfection effects.