Dehygant LFM Nitrogenous heterocyclic compound Cognis Preservative >> Biocide, In-can preservative Coatings >> Waterborne Use In-can-preservative for emulsion paints, emulsions, aqueous pigment pastes, etc. Nitrogenous heterocyclic compound. Properties Given that the correct amounts are used, DEHYGANT LFM prevents spoilage by micro-organisms on storage. In our microbiological laboratories we determined the inhibiting concentration of DEHYGANT LFM against a wide spectrum of micro-organism. We obtained the following results: Testorganism Inhibiting concentration in % Staphylococcus aureus 0.05 Escherichia coli 0.06 Pseudomonas aeruginosa 0.07 Mycobacterium phlei 0.05 Candida albicans 0.175 Trichophyton mentagrophytes 0.004 Chaetomium globosum 0.08 Aspergillus niger 0.15 spergillus tamarii 0.175 Aspergillus flavus 0.07 Aspergillus spec. 0.08 Penicillium camerunense 0.20 Penicillium luteum 0.175 Penicillium spec. 0.15 Although DEHYGANT LFM can be used without trouble in most polymer dispersions or paints based on these dispersions, it is not recommended for use in casein paints or systems containing similar natural materials. In case of high monomer content in vinylacetate homo and copolymers DEHYGANT LFM may lead to discolourations. Therefore, tests are necessary. Dosage According to our experience addition should lie between 0.1 to 0.5% of the ready-made paint. However, the required dosage should be determined by tests taking local production facilities and conditions into consideration. By all means, the following conditions should not be omitted: The vital factor for spoilage of emulsion paints is a microbial infection which may be introduced by air, water, pigments or other additives and depending on the circumstances the mixture of germs may vary widely. The finished paint can provide a nutrient medium for micro-organisms and it must be considered that polyvinyl acetates and polyacrylates may be attacked by micro-organisms; however, cellulose derivatives most frequently used for thickening purposes form a far better nutrient medium. The more cellulose derivatives are in a given emulsion paint, the greater, as a rule, is the danger of a microbial decomposition. Generally, one should endeavour to repeatedly clean all production equipment, thus preventing a built-up of infection. By this means, satisfactory results may be obtained with a reasonable concentration of preservative. DEHYGANT LFM is best incorporated at the pigment dispersion stage; this ensures good homogeneization and also limits potential infection. However, it can also be post-added to the finished paint and in this case it should be dissolved in suitable solvents prior to incorporation with thorough stirring. Miscellaneous In our toxicological laboratories DEHYGANT LFM has been examined for toxicity to rats by administration with a probang. It was also examined for toleration by the skin and mucous membranes. In experimental tests with animals, DEHYGANT LFM proved to be tolerated better by the skin and mucous membranes than formalin. The LD50 is 3.6 g/kg body weight. In-can-preservative for emulsion paints, emulsions, aqueous pigment pastes. Not recommended for use in casein paints or systems containing similar natural materials. In case of high monomer content in vinylacetate homo and copolymers, it may lead to discolourations. Recommended usage level: 0.1 to 0.5% of the ready-made paint. Incorporated at the pigment dispersion stage; this ensures good homogeneization and also limits potential infection. However, it can also be post-added to the finished paint and in this case it should be dissolved in suitable solvents prior to incorporation with thorough stirring.