Methyl isothiazolinone | Efficient Broad-spectrum Fungicide and Preservative
Product Name: Methylisothiazolinone (MIT)
Chemical Name: 2-Methyl-4-isothiazolin-3-one, 2-Methyl-3(2H)-isothiazolone
CAS Number: 2682-20-4
EINECS Number: 220-239-6
INCI Name: Methylisothiazolinone
Active Content: 10% (Aqueous Solution), 50% (Aqueous Solution), 99% (Crystalline Powder)
Appearance: Colorless to pale yellow clear liquid (solution); white crystalline powder (pure)
Molecular Formula: C₄H₅NOS
Molecular Weight: 115.15 g/mol
Methylisothiazolinone, MIT, CAS 2682-20-4, 2-Methyl-4-isothiazolin-3-one
Methyl isothiazolinone | Efficient Broad-spectrum Fungicide and Preservative(CAS 2682-20-4)
Methylisothiazolinone (MIT, CAS 2682-20-4) is a highly effective, fast-acting isothiazolinone-class biocide and preservative renowned for its exceptional broad-spectrum antimicrobial activity at extremely low concentrations. As a heterocyclic organic compound, it has been widely used for over 40 years in industrial and consumer applications.
MIT exerts its antimicrobial effect through rapid disruption of microbial cell membranes and inhibition of critical metabolic enzymes, providing fast and effective control against Gram-positive and Gram-negative bacteria, yeast, mold, and algae. Its unique mechanism of action prevents biofilm formation and eliminates existing microbial contamination.
While highly effective, MIT is recognized as a skin sensitizer and is subject to strict global regulatory controls, particularly in cosmetic applications. It remains the gold standard preservative for industrial water-based systems due to its cost-effectiveness, broad efficacy, and compatibility with most industrial raw materials.
Certificate of Analysis (COA)
Item | Specification | Test Result |
Product Identification | ||
Product Name | Methylisothiazolinone 10% Solution | Methylisothiazolinone 10% Solution |
Quality Parameters | ||
Appearance | Clear colorless to pale yellow liquid | Clear colorless liquid |
Active Content (HPLC) | 9.0 - 11.0% | 10.12% |
Color (APHA) | ≤50 | 20 |
pH Value | 2.0 - 4.0 | 3.1 |
Density (20°C) | 1.01 - 1.03 g/mL | 1.021 g/mL |
Magnesium Nitrate | 22.0 - 24.0% | 23.15% |
Copper Content | ≤5 ppm | <2 ppm |
Heavy Metals (as Pb) | ≤10 ppm | <5 ppm |
Arsenic (As) | ≤2 ppm | <1 ppm |
Mercury (Hg) | ≤1 ppm | <0.1 ppm |
Stability (54°C, 14d) | ≥90% MIT retention | 96.8% |
Microbiological Test | ||
Total Aerobic Count | ≤100 CFU/g | <10 CFU/g |
Yeast & Mold | ≤10 CFU/g | <10 CFU/g |
Conclusion | Qualified | Qualified |
Key Benefits
✅ Ultra-High Efficacy - Effective at ppm-level concentrations (5-50 ppm), significantly lower than traditional preservatives
✅ Rapid Kill Kinetics - 99.9% microbial reduction within 1-2 hours, faster than most competing preservatives
✅ Broad-Spectrum Activity - Excellent control over bacteria, yeast, mold, and algae; prevents biofilm formation
✅ Excellent Water Solubility - Fully miscible with water in all proportions, easy to incorporate into formulations
✅ Cost-Effective - Low use rates result in extremely low cost-in-use per metric ton of finished product
✅ pH Versatility - Effective across pH 4-9 range, suitable for most industrial and cosmetic formulations
✅ No Formaldehyde Release - Does not release formaldehyde, meeting non-formaldehyde preservative requirements
✅ Compatible with Most Raw Materials - Works with surfactants, emulsifiers, proteins, and most formulation ingredients
✅ Prevents Biofilm - Unique mechanism disrupts existing biofilms and prevents new biofilm formation
Applications
Cosmetic Applications (Restricted):
• ONLY rinse-off products: Shampoos, hair conditioners, body washes, shower gels, liquid soaps, facial cleansers
• STRICTLY PROHIBITED in: Leave-on products, creams, lotions, sunscreens, makeup, baby products, wet wipes, eye products, mucosal products
Frequently Asked Questions (FAQ) & Document Request
Q1: What is the difference between MIT alone and CMIT/MIT (Kathon CG) mixture?
A: Pure MIT (Methylisothiazolinone) is the single active ingredient at 10% or 50%. CMIT/MIT (3:1 ratio, commonly called Kathon CG or "卡松") is a mixture of 5-Chloro-2-methyl-4-isothiazolin-3-one + Methylisothiazolinone. Both are regulated identically in cosmetics - max 0.0015% total actives in rinse-off products only.
Q2: Can MIT be used in leave-on cosmetic products?
A: NO. MIT is PROHIBITED in all leave-on cosmetic products in the EU (since 2017), including creams, lotions, serums, sunscreens, makeup, wet wipes, and baby products. It may ONLY be used in rinse-off products (shampoos, body washes, etc.) at strictly limited concentrations.
Q3: What is the maximum allowable concentration in cosmetics by region?
A:
• EU: 0.0015% (15 ppm) max, RINSE-OFF ONLY, leave-on PROHIBITED
• China: 0.01% (100 ppm) max, rinse-off only (proposed revision to 0.0015%)
• US: 0.01% max in rinse-off, 0.0015% recommended for leave-on (not banned but not recommended)
• Japan: 0.01% max with restrictions
Q4: What ingredients are incompatible with MIT?
A: MIT is incompatible with: strong reducing agents (sulfites, bisulfites, thiols), strong nucleophiles (amines, amino acids, proteins at high concentrations), and high levels of glutathione. It is stable with most surfactants, emulsifiers, and standard cosmetic ingredients at pH 4-9.
Q5: What are proper storage conditions for MIT solutions?
A: MIT is photosensitive and temperature-sensitive. Store at 2-8°C (36-46°F) in original containers, protected from direct sunlight and freezing. Do not store above 25°C for extended periods. Under proper conditions, shelf life is 12 months from manufacture.
Q6: Is MIT suitable for natural or organic cosmetic formulations?
A: No, MIT is not approved for use in certified organic or natural cosmetic standards (Ecocert, COSMOS, NATRUE) and is generally avoided in clean beauty formulations due to sensitization concerns and regulatory restrictions.
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