Isothiazolinones

CAS Nos.: 26172-55-4, 2682-20-4

Relative Molecular Mass: 115.16

Structural Formula：

Properties & Applications

Isothiazolinones are primarily composed of 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) and 2-methyl-4-isothiazolin-3-one (MI). Their biocidal mechanism lies in breaking the protein bonds of bacteria and algae. Upon contact with microorganisms, isothiazolinones rapidly and irreversibly inhibit microbial growth, leading to cell death. Therefore, they deliver potent inhibitory and bactericidal/fungicidal/algaecidal effects against common bacteria, fungi and algae.

This product features high biocidal efficiency, excellent biodegradability, zero residual formation, safe operation, good compatibility, outstanding stability and low application cost. It is miscible with chlorine and most anionic, cationic and nonionic surfactants. At high dosages, it exhibits remarkable performance in biological slime stripping.

As a broad-spectrum, high-efficiency, low-toxicity non-oxidizing biocide, isothiazolinones are widely applied in oilfield, papermaking, pesticide, cutting fluid, leather processing, printing ink, dyestuff and tanning industries.

Technical Specifications (Compliant with HG/T 3657-2017)

Note: Custom concentrations including 1.5%, 14% are available upon customer request.

Application Instructions

For Class II isothiazolinones:

As slime stripping agent: Dosing concentration 150–300 mg/L

As biocide: Dosing interval 3–7 days, dosage 80–100 mg/L

It can be used simultaneously with oxidizing biocides such as chlorine, but is prohibited for cooling water systems containing sulfides. Combined use with quaternary ammonium salts achieves superior performance.

When used as industrial biocide and mildew inhibitor, the typical working concentration ranges from 0.05% to 0.4%.

Packaging & Storage

Packed in plastic drums of 25 kg each; custom packaging specifications available on demand. Store indoors in cool shaded areas with a shelf life of 10 months.

Safety & Protection

Isothiazolinones are corrosive to human skin, capable of causing skin burns and allergic dermatitis with persistent irritation lasting several hours. Direct contact with skin and eyes is strictly forbidden. Operators shall wear protective goggles, rubber gloves and other labor protection articles during handling.

In case of skin contact: Immediately remove contaminated clothing and footwear, flush the affected area with copious clean water for no less than 15 minutes, apply urea acetate ointment or burn ointment to the wound, and seek medical treatment without delay.