Isothiazolinones can be mixed with some chemicals to enhance efficacy, but there are strict compatibility requirements:
Compatible chemicals: They can be mixed with non-oxidizing biocides (e.g., bronopol, dodecyl dimethyl benzyl ammonium chloride) in water treatment to achieve a "broad-spectrum bactericidal" effect; in coatings, they can be mixed with defoamers (e.g., silicone defoamers) and thickeners (e.g., hydroxyethyl cellulose) without chemical reactions.
Incompatible chemicals: They cannot be mixed with strong oxidizing agents (e.g., hydrogen peroxide, sodium hypochlorite), because oxidizing agents will decompose the isothiazolinone ring, reducing its bactericidal activity or generating toxic by-products. They also cannot be mixed with strong reducing agents (e.g., sodium sulfite) or high-concentration anionic surfactants (e.g., sodium dodecyl benzene sulfonate) in large quantities, which may cause precipitation or reduce the stability of isothiazolinones.
Precautions: Before mixing, a small-scale compatibility test (e.g., mixing 100 mL of the two solutions in a beaker and observing for 24 hours) should be conducted to check for discoloration, precipitation, or gas generation.
