Bacteriostatic and antiseptic agent suitable for use in metal cutting fluids
4. Isothiazolinones
(CIT/MIT): This product is mainly added after the use of cutting fluid to effectively kill bacteria, molds and yeasts. The general addition amount is 100 to 200 ppm.
(2) BIT20: Its chemical name is 1,2-benzothiazolin-3-one. It is a broad-spectrum fungicide effective against bacteria, yeasts, and molds. It has a long duration, low odor, a pH range of 2-12, low toxicity, good safety, and excellent thermal stability. BIT20 is compatible with other fungicides and is often used in high-temperature and strongly alkaline environments where other preservatives are ineffective. It can be used in concentrated solutions or working solutions. Recommended dosage (relative to the diluent): 0.1-0.2%. It is advisable to be used in combination with fungicides in concentrated solutions.
(3) OIT: Its chemical name is (2-Octyl-4-isothiazolin-3-one). It is a broad-spectrum antifungal agent and has certain bactericidal and algicidal effects. Compared with other antifungal agents, OIT has higher water solubility and also has wide compatibility, being compatible with various metal processing liquid formulations. However, it is unstable at high pH (＞9.5). It is generally used in working fluids and the recommended dosage (relative to the diluent) is: 0.02 - 0.2%. It can be used in combination with antibacterial agents.
(4) MIT: Its chemical name is 2-methyl-4-isothiazolin-3-one. It is a broad-spectrum inhibitor of bacteria, molds and yeasts. It has a long duration, low odor, no solvents, zero VOC, a pH range of 4-9.5, low toxicity, good safety, and particularly excellent thermal stability. It can be used in concentrated solutions or working solutions. The recommended dosage is 100-300 ppm (in diluted solutions). It is suitable to be used in combination with fungicides.
(5) BBIT: Its chemical name is -butyl-1,2-benzothiazolin-3-one. It is effective against bacteria, molds, yeasts, and some algae, has a long duration, a low odor, and a pH range of 4-10. It also has excellent thermal stability and chemical stability, and has wide compatibility. It can be used in concentrated solutions or working solutions. The general recommended dosage is 100-400 ppm (in diluted solution).
5. Pyridine derivatives
Pyridine-based fungicides: Their chemical name is 2-mercaptopyridine-1-oxide salt. They are broad-spectrum fungicides effective against bacteria, yeasts, and molds. The pH range applicable to this structure is 4-9. They have long persistence, low toxicity, and no odor. They can provide comprehensive microbial protection for metal processing fluids. When used, they can be applied in concentrated solutions or for post-treatment of contaminated processing fluids. The recommended dosage (relative to the dilution solution): 0.02-0.1%. They can be used in combination with antibacterial agents. Caution should be exercised when used in systems with a large amount of iron ions, as there may be some color change.
6. Organic Halogen Compounds
IPBC: Its chemical name is 3-iodo-2-propynyl-butyl-methylamine ester. It is a highly effective and low-toxic fungicide. Its applicable pH range is 4-10, with a long duration of action and a high specific activity; it has a good preventive and killing effect on fungi in metal processing liquid systems (both water-based and oil-based), with a concentration of 0.1-0.3% in the concentrated solution. IPBC has poor efficacy against bacteria and can be used in combination with antibacterial agents.
DBNPA: Its chemical name is 2,2-dibromo-3-aminoacrylamide. It is a fast-acting, highly efficient and low-toxicity disinfectant, effective against bacteria, molds and yeasts. Its pH range is 3-9.5, and the temperature should not exceed 50℃. It undergoes rapid hydrolysis in alkaline environments. While effectively eliminating microbial contamination, there is little DBNPA residue in the system. Its final degradation products are CO2 and H2O. It is generally used in working solutions, and the recommended dosage is 0.05-0.1%. This structure has good compatibility with isothiazole type disinfectants.
Broponol: Its chemical name is 2-bromo-2-nitro-1,3-propanol. It is a bactericidal agent, especially targeting Pseudomonas. Its pH range is 3-9 and it is a formaldehyde releaser. It is generally used in working solutions and the recommended dosage is 350 - 1000 ppm. This structure has good compatibility with isothiazole type fungicides.
7. Phenols
(1) OPP: Its chemical name is 2-phenylphenol. It is a broad-spectrum fungicide and also has certain antibacterial properties. It is easily biodegradable and has rapid efficacy. It is particularly suitable for high alkaline and high-temperature systems. The working solution uses 0.1 - 0.25%, and the concentrated solution uses 0.12 - 2.4%. Due to the certain irritation to the eyes caused by this structural formula, be sure to protect your eyes when using it.
(2) PCMX, PCMC, DCMX series: This series of products is a safe and efficient mold and bacteria inhibitor, without irritation and low toxicity. It has good chemical stability, can withstand high temperatures and high pH levels, and generally does not lose its activity under normal storage conditions. Its solubility in water is relatively low, and it is easily soluble in organic solvents such as alcohols, ethers, ketones, and alkaline aqueous solutions. It is suitable for concentrated liquid anti-corrosion and mold prevention systems. The recommended dosage is generally 1-3%.
8. Glutaraldehyde
Glutaraldehyde is a broad-spectrum and rapid-acting disinfectant, especially effective against SRBs. This compound has a low toxicity and is easily biodegradable. Its applicable pH range is 7-10 and it can be used in working solutions. Generally, a concentration of 200-2000 ppm is recommended.
9. Others
There are many chemical bactericides that can be used to stabilize the biological properties of metal processing fluids. There is no such thing as the "best" bactericide; there are only the most suitable ones.
