coating anti-mildew agent action mechanism agent description
Anti-mildew agent is a kind of polymer material additive that can inhibit mold growth and kill mold. It can prevent polymer material from fungus erosion and maintain good appearance and physical and mechanical properties. Whether it is water-based coating or solvent-based coating, it is easy to receive mold and algal fungus erosion in the environment, especially in high temperature and high humidity environment, causing film discoloration, polymer degradation, etc., so that it loses its use value.
The paint is contaminated by microorganisms, and the phenomenon of viscosity decline, pigment settlement, odor, gas generation, container expansion, pH drift and system damage is called corruption. In solvent-based coatings, the problem of spoilage is not prominent. Mold erosion of the film, resulting in film color change, sticky, perforation, damage and peeling, loss of adhesion, affecting the protective performance of the film and the cleanliness and appearance of the material, reduce mechanical properties, shorten the service life, and cause harm to environmental health.
The natural polymer materials used in the coating contain casein, soybean protein, alginic acid, starch, natural gum, cellulose derivatives, fat and other substances that can be ingested by mold, and are susceptible to mold damage. Most synthetic polymer materials have strong antibacterial properties, and some varieties (such as polyurethane, polyacrylate, polyvinyl acetate, polyvinyl alcohol, pervinyl chloride, vinylidene chloride, etc.) have poor bacterial resistance due to their structure and are easy to be decomposed by mold. Additives used in coatings (such as plasticizers, heat stabilizers, light stabilizers, organic fillers, colorants, etc.) are both nutrient sources of molds, and many varieties are bacterial substances. Adding these additives is often the main cause of bacterial damage to coatings and coating films. The dust adsorbed on the surface of the coating is also a nutrient source for breeding mold
Action mechanism
The bacteria that cause emulsion and coating spoilage include flavobacterium odoratum, enterobacter aerogenes, pseudomonas, Escherichia coli, Streptococcus faecalis; The main strains that cause mildew are Aspergillus variegatus, cladospore, Paecilomyces wani and penicillium purpura. Molds are a vast group of microorganisms that are found almost everywhere in soil, water, plant and animal life, or air. Mold depends on absorbing nutrients from other objects, to survive in a parasitic or saprophytic way, can secrete a variety of enzymes, break down organic matter into easily ingested nutrients. As long as there is very little nutrition, under the appropriate temperature (26 ~ 32 ° C) and relative humidity (> 85%), mold can grow and reproduce. The killing effect of coating anti-mildew agent on mold is to enter the cell through the cell membrane of the spores, preventing spores from germinating or killing spores. The toxic action of anti-mildew agent on mold includes the following ways: eliminate or inhibit the activity of various metabolic enzymes in mold cells; React with amino or sulfhydryl groups of enzyme proteins to inhibit or destroy their functions; Inhibit RNA synthesis during spore germination, thus preventing spore germination; Accelerate the promotion of phosphoric acid oxidation-reduction system to destroy cell function; Destroy the energy release system in mold cells; Inhibition of electron transfer system and transaminase system.
