Most preservatives react with certain components of the cell wall, mainly proteins, after contacting with the cell membrane, destroying the protective structure of microbial cells or interfering with the metabolism of the cells, affecting the normal function of the cells. The growth order is achieved to achieve the purpose of antisepsis. The cations mainly affect the osmotic pressure, causing the cell membrane to rupture, shrink and lose water, thereby sterilizing.

1), imidazolidinyl urea

ISP company’s Germall 115, Germall Ⅱ, Germaben Ⅱ-E, Germall plus, Germall IS-45. In the Jiemei series, the main ingredient is imidazolidinyl urea, which is a formaldehyde donor. It achieves the purpose of sterilization by slowly releasing formaldehyde during the application process. The main ingredient of Germall 115 is imidazolidinyl urea, which has worse antibacterial activity than Germall II (bis-imidazolidinyl urea). Germaben II-E is a compound of paraben esters, which is more effective against molds and yeasts than either alone. There are advantages in terms of components. Germall plus and Germall IS-45 are compounds of iodopropynylbutylcarbamate. The market response is also good. However, be careful to avoid ingredients that may inhibit its activity in the formula. In addition, the iodine of 1 in the preservative Propargyl butylcarbamate has poor water solubility. If it is not dissolved with an organic solvent during operation, its antiseptic effect may also be affected. Germall IS-45 is a newer variety sold by ISP Company, which contains methylparaben 5, which enhances its ability to inhibit mold and yeast.

2), Hydantoin

LONZA’s glydant plus, DMDMH, NIPA’s DMDMH. This product is also a formaldehyde donor. Glydant plus is a compound of iodopropynylbutylcarbamate. The content of iodopropynylbutylcarbamate is 5. In addition, LONZA also provides liquid glydant plus (propylene glycol solution) which is said to have an active content of 50%. It should also be noted that components such as reducing agents in the formula may have an inhibitory effect.

3), Isothiazolinone

Rohm and Haas's Kathon CG, 950, LONZA's isocil pc, Samp; M's EUXYL K100, EUXYL K727. This product is also a formaldehyde donor. LONZA's isocil pc is composed of two isothiazolinones. 23 magnesium salts are added to the formula for synergy, mainly to change the osmotic pressure. K727 is a compound of methyldibromoglutaronitrile. EUXYL K100 is a compound of benzyl alcohol, which also has considerable anti-corrosion capabilities for the gas phase.

4), Parabens (parabens)

Zhejiang Shengxiao, ISP Company’s liquapar oil, Samp; M Company’s EUXYL K300, NIPA’s phenip et al. This type of preservative is one of the most widely used preservatives at present, but the dosage is relatively large. As the carbon chain grows, its water-soluble phase gradually becomes worse, affecting its distribution rate in the water phase. Its anti-mildew effect is outstanding. Methyl paraben has the best water solubility and can often be added directly to the water phase; while ethyl paraben, propyl ester, butyl ester and isobutyl ester tend to dissolve in the oil phase.

Methyl paraben is a preservative suitable for acidic systems. It has the highest antibacterial activity of 77% at pH 5, 63% at pH 7, and close to 50% at pH 8.5. Therefore, the activity of parabens in a system can be improved mainly by lowering the pH of the system, usually 7.0 to 6.5 or lower, although sometimes they can maintain their efficacy in systems with a slightly higher pH.

5), Quaternary ammonium salt-15

This type of product is currently only Dowicil 200 from Dow Chemical Company.

Dowicil 200 does not dilute formaldehyde, but its antioxidant capacity is better than ISP's Jiemei. In some formulas that are prone to discoloration, it is common practice to add a small amount of sulfite to prevent it.

6), domestic Kaisong-CG (chemical structure is the same as Category 3)

Zhejiang Shengxiao’s CY-1, Shandong Mingda’s MD-2000, Jiangsu Xinke’s Xinke- 99. Shaanxi China Resources’ KS-1 and Xi’an Pioneer’s XF-1. This type of product is also a formaldehyde donor. In terms of use, it is sensitive to PH value and can play a very good anti-corrosion effect in an acidic environment. The dosage is very small, about 0.08 can play a very good role. However, in an alkaline environment, it will lose its antiseptic activity. In this type of product, in order to increase its antiseptic activity, magnesium salt will be added to increase its osmotic pressure. Therefore, when using this product, the compatibility between raw materials must be considered to avoid precipitation, especially in transparent product, be very careful. In addition, amines, mercaptans, sulfides, sulfites, and bleaches can also deactivate Kezon.

7), In addition, there are benzoic acid/benzyl alcohol and derivative preservatives, alcohols and derivative preservatives,

The most representative one is phenoxyethanol , it is a good solvent and preservative. In the preparation of preservatives, it is often used as a solvent to dissolve other oil-soluble preservatives. However, it itself can be used as an emulsifier, so its effect on the product itself must be considered when using it. Influence. It should also be noted that phenoxyethanol is unstable under certain high pH conditions.

8) Benzoic acid/sodium benzoate/potassium sorbate

Benzoic acid/sodium benzoate/potassium sorbate are mainly used in food, so they are listed together. Its antiseptic mechanism is: benzoic acid preservatives act on their undissociated molecules. Undissociated benzoic acid is highly lipophilic and can easily pass through the cell membrane and enter the cell, interfering with the permeability of the cell membranes of microorganisms such as molds and bacteria. , hinders the absorption of amino acids by cell membranes, enters benzoic acid molecules into cells, acidifies alkali storage in cells, inhibits the activity of respiratory enzymes in microbial cells, and thus plays a preservative role.

This type of preservative also belongs to the category that is effective in acidic systems. Sorbic acid and benzoic acid are inactive at pH 7 and exhibit 37% and 13% activity respectively at pH 5. Therefore, they should be used in acidic systems. application in the medium.

9) Bronopol

Bronopol is the abbreviation of 2-bromo-2-nitro-1,3-propanediol and has broad-spectrum antibacterial properties It can effectively inhibit most bacteria, especially Gram-negative bacteria. It is unstable under high temperature and alkaline conditions and becomes darker under sunlight. Brobol is compatible with most surfactants, but when substances containing -SH groups, such as cysteine, are included in cosmetic raw materials, Brobol's antibacterial activity will be reduced. In addition, metallic aluminum can also reduce the antibacterial activity of Brobol.