Methyl-isothiazolinone

METHYL ISOTHIAZOLINONE Active at very low concentrations Maximum use level 15ppm... 

The most commonly used preservatives that do not release formaldehyde are parabens, quatemium-15, and a mixture of chloromethyl isothiazolinone and methyl isothiazolinone (Kathon CG) [3,63,98,99],... 

Dowicil 22 has the Cosmetics Toiletries and Fragrance Association (CTFA) designation Quaternium-15 and is sometimes used between 0.05 and 0.2% and can be used in combination with parabens to enhance their preservative capacity. Kathon CG, a mixture of methyl chloroisothiazoli-none and methyl isothiazolinone, is another useful preservative for the preservation of cosmetic hair products. 

Chem. Descrip. Benzisothiazolinone, chlormethyl isothiazolinone, and methyl isothiazolinone aq. disp. 

Chem. Descrip. Chlormethyl isothiazolinone and methyl isothiazolinone... 

Bodoxin 1-Amino propan-2-ol + 5-chloro-2-methyl-4-isothiazolin-3-one + 2 methyl isothiazolinone... 

Fernandez de Corres L, Navarro JA, Gastaminza G, Del Pozo MD (1995) An unusual case of sensitization to methylchloro- and methyl-isothiazolinone (MCI/MI). Contact Dermatitis 33 215... 

The author also investigated the comparative effects of physical and chemical monomer reduction (stripping) on chloromethyl and methyl isothiazolinones in a polyvinyl acetate/butyl acrylate co-polymer dispersion in a large scale plant trial. Results are detailed in Table 16 and show that even under apparently strongly oxidising conditions CIT was degraded by up to 75% when redox monomer reduction was used. In comparison no such effect was seen with the physically stripped samples. 

Nevertheless because of its low cost, rapid efficacy and headspace effects formaldehyde is still a popular biocide, especially when combined with more modern actives such as chloromethyl and methyl isothiazolinones. 

Bronopol is rarely used alone for the preservation of polymer dispersions, being most commonly part of a combination biocide system, e.g. with chloromethyl/methyl isothiazolinone. In such formulations it helps to eliminate the weakness of 5-chloro-2-methyl-4-isothiazolin-3-one against anaerobic sulphate reducing bacteria and has been shown to be effective against slow growing acidophilic species such as Gluconoacetobacter liquefaciens (Herrick, 2001). 

Because of the cost and timescale for the development of new active substances and the registration and regulatory requirements, there have been no unique biocidal actives widely used for protection of polymer dispersions during the last 20 years, since the chloromethyl/methyl isothiazolinone blend was introduced. 

Information will be given on a novel isothiazolinone combination biocide offering many advantages over traditional chloromethyl/methyl- and benz-isothiazolinone based preservatives. 

Although the "ideal biocide" for the wet-state protection of paints still waits to be discovered the recent development of the methyl/benz-isothiazolinone blend offers many advantages over currently used preservatives. 

Because the objective of this work was to assess the benefits of encapsulation, it was decided to opt for one structural class of biocide. The biocides selected for this purpose were based on the isothiazolinone structure. 2 Examples include 2-octyl-4-isothiazolin-3-one (OIT), 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT), 5-chloro-2-methyl-4-isothiazolin-3-one (CIT) and 2-methyl-4-isothiazolin-3-one (MIT) (Figure 1). 

Another major chemistry often used are isothiazolinones. There are a number of different varieties of this chemistry, probably the most common form used is supplied as a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one, (see Figure 5, usually in the ration of 3 1). 

In the multicenter study of the Information Network of Departments of Dermatology, sensitization rates of preservatives in the standard series were all over 1% in the test population of 11485 patients. Thiomersal was rating highest (5.3%), chloromethyl-isothiazolinone/methyi-sothiazolinone, formaldehyde, and methyl-dibromo-glutaronitrile/phenoxyethanol were next at about 2%, and parabens rating lowest at 1.6%. Glutaral, a biocide... 

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