Technical specifications of CMIT/MIT isothiazolinone preservative

Appearance: light transparent liquid
Active ingredient(%): (from)1.5-14
Chlorine ratio (A:B) 1:2.6-3.5, 9:1
Odor: slight
Density(25℃): 1.10-1.20
PH value: 2-5
Solubility: soluble with hydrolyzed protein, various ionic emulsifiers and surfactants

Theoretically, if the polymer contains only such simple chemical bonds without chromophore groups, it will not be enough to absorb ground sunlight at 295~400nm, and there will be no photodegradation problem. Polyolefin materials and systems such as acrylic coatings, aliphatic polyesters, and polyurethane coatings all fall into this category. But in fact, more or less photosensitive impurities are inevitable in polymer materials. The absorption of light energy by these photoactive components may initiate the photoaging process of polymers. This is the case with titanium slag in polyolefin materials. . In addition, the raw materials for paint production come from petroleum processing, and the heaviest aromatic impurities and ketone oxidation products will also play a role in light absorption. In the case that the coating resin itself contains aromatic rings, large conjugated structures or chromogenic groups, the coating may directly absorb sunlight energy, triggering photo-oxidation and photo-degradation reactions.

Photooxidation of polymers
Oxygen is a key factor in the photoaging process of polymer coatings. It can induce or participate in the polymer photoaging process in the form of ground state triplet oxygen molecules 3Oz, excited state singlet oxygen molecules ’02 and ozone O. Ground state oxygen molecules have low energy and relatively low reaction activity, but they exist in large amounts in the environment and have high concentrations. The higher activity of ‘0, and 0 can be produced under conditions such as photosensitization. In the atmosphere, the polynuclear aromatic hydrocarbons produced by the combustion of organic matter such as fuel and solvents can photosensitize oxygen molecules under the action of sunlight. Typically, the compound anthracene absorbs sunlight ultraviolet rays and sensitizes sasol fischer tropsch wax triplet oxygen into high-energy singlet oxygen. The photosensitization reaction is as follows:

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In addition to fused ring aromatics, other aromatic ketones, heteroatom-containing conjugated compounds, dyes, etc. may also be sensitized to produce singlet oxygen. Singlet oxygen molecules have two energy levels, 94.6kJ/mol and 157kJ/mol, respectively. The lower energy state is more likely to appear. According to the law of photochemical energy transfer, when light-absorbing molecules excite the triplet energy ET(s) When the energy Ey(‘Oz) of the singlet oxygen molecule is higher than that, it is possible to achieve photosensitization, that is, energy transfer, to obtain singlet oxygen. Ozone can also react to produce singlet oxygen.