Microbial contamination has always been a key challenge in chemical and adhesive production, affecting product stability and shelf life. Isothiazolinone biocides, with their high efficiency and broad-spectrum properties, have gradually become the “invisible guardian” in adhesive preservation programs. This kind of biocides through the destruction of microbial protein structure, to achieve rapid inactivation, its mechanism of action is similar to the “precision sniper”, can quickly lock the core of the life activities of bacteria, fungi or algae, so that they lose the ability to reproduce.
Chemical properties and principle of action of isothiazolinones
The molecular structure of isothiazolinone (chemical formula C8H9ClN2O2S2) consists of two core components: 5-chloro-2-methyl-4-isothiazolin-3-one (CIT) and 2-methyl-4-isothiazolin-3-one (MIT). These two active ingredients work together like a pair of “molecular scissors” to cut the protein bonds in the microbial cell, leading to the collapse of its metabolic system. Experiments have shown that even at very low concentrations (usually 0.01%-0.1%), a bacterial inhibition rate of more than 99% can be achieved, and this “four-two-thousand-kilogram” effect makes it very cost-effective in industrial applications.
Adhesive production of microbial prevention and control pain points
Adhesives in the natural polymer materials (such as starch, cellulose) and high moisture content of the formula, it is very easy to become a microbial “hotbed”. If no preservative is added, the product may experience viscosity loss, pH drift or even mold and deterioration during storage. Traditional preservatives such as formaldehyde releasers are inexpensive but environmentally toxic, while isothiazolinones are internationally recognized as a green alternative, with low-toxicity properties that meet the requirements of the European Union’s REACH regulation.
Application and process optimization
In actual production, the addition of isothiazolinone needs to grasp two key nodes: one is to add the sizing agent immediately after the completion of production, and the second is to ensure uniform dispersion through high-speed mixing. To a medium-sized adhesive factory, for example, according to the 0.05% ratio of CIT / MIT composite preparation, the product shelf life from 3 months to 12 months, and does not affect the curing speed and bond strength. It is worth noting that the compatibility of different adhesive systems (such as water-based acrylate and solvent-based polyurethane) on the fungicide varies, and it is recommended to determine the optimal ratio through a small test.
Economic benefits and industry trends
Compared with traditional fungicides, the use of isothiazolinone can be reduced by 30% -50%, but the comprehensive anticorrosion effect increased by about 2 times. This “cost reduction and efficiency” feature is especially suitable for large-scale continuous production of adhesive enterprises. At present, a new generation of isothiazolinone derivatives such as OIT (octyl isothiazolinone) has begun to be used in high-temperature adhesives, which can still remain active at 120 ℃ environment, for automotive adhesives and other high-end areas to provide solutions.
With increasingly stringent environmental regulations, the adhesive industry is accelerating towards sustainable development. Isothiazolinone biocides through molecular design innovation and process adaptation, will continue to play a central role in the microbial prevention and control system. For manufacturers, the rational use of such “microbial nemesis” is not only a choice of technological upgrading, but also a strategic investment to cope with market competition.