What are the main ingredients of preservatives (二）
Alkylammonium compounds (AAC)
Alkylammonium chloride (AAC) is the general name of the third and fourth ammonium salts. It is effective to A wide range of organisms, has little impact on the environment, and has good natural degradability. The appearance and processing properties of treated wood are similar to those of untreated wood, and it has great application potential. As a wood preservative, AAC is water-soluble and its price is similar to that of copper-chromium-arsenic preservatives, but its anti-loss effect is lower than that of copper-chromium-arsenic preservatives.
Among alkyl ammonium salts, quaternary ammonium salts have been used as wood preservatives. Quaternary ammonium salt is a cationic surfactant. Since Domagk G found that quaternary ammonium salt containing long chain alkyl groups has strong bactericidal properties more than half a century ago, it has been gradually introduced into the wood protection industry. The selection of quaternary ammonium salts as wood preservatives revolves around the following aspects:
1) Broad spectrum of sterilization, that is, the product has strong killing and inhibiting ability to a variety of wood rot bacteria;
2) The product has low toxicity, good biodegradability and no adverse impact on the environment;
3) The product has good solubility in water, light and heat resistance, and good storage stability;
4) Surface tension should be small, infiltration, permeability is stronger;
5) Good compatibility with other preservatives and pesticides.
Quaternary ammonium preservatives have been developed for many generations. In some developed countries, it is widely used as wood preservative and wood discoloration agent, and some varieties can also be used as pest control agent. The relationship between the structure of quaternary ammonium compounds and bactericidal power was studied in detail. It is considered that dimethyl didecyl ammonium chloride (DDAC) is the most promising wood preservative and anti-discoloration agent. DDAC has a natural affinity for wood and is fixed on wood through cation exchange. It can be used as a wood preservative in situations of contact with the ground. However, its fixing speed is relatively slow, usually taking two weeks. It has been registered for use in some European and American countries.
Foreign studies on DDAC mainly focus on the application of combination with other agents as preservatives, anti-color agents and anti-mildew agents. Basic studies on anti-corrosion and bactericidal mechanism have not been systematically reported. There is no research on the application of DDAC in wood preservation in China.
