Most powder coatings will cause different degrees of adverse effects on the environment and human body during production and use. On the one hand, heavy metal pigments are widely used in powder coating and other industries because of their wide range, strong hiding power and low quality, but because heavy metals cannot be biodegraded after entering the human body, after dissolving into the blood, it will lead to anemia, dizziness, arteriosclerosis, etc., and lead poisoning in children will also lead to problems such as stunting and mental retardation.
Powder coatings not only have a negative impact during the production process, but also after the product has been sprayed. Therefore, it is necessary to be cautious when using children's utensils, food packaging, household appliances, and items that are in long-term or repeated contact with the human body.
On the other hand, organotin compounds are often used as catalysts for the synthesis of polyester resins in the production process of powder coatings due to their high activity and good performance. However, in recent years, there have been several incidents of non-industrial poisoning of organotins, which have aroused the attention of all parties to the toxicity of organotins.
At present, organotin compounds have been identified as endocrine disruptors and important persistent toxic substances. The toxicity of organotin compounds is related to the number and type of R substituents in the molecular formula, among which dibutyltin (DBT), tributyltin (TBT) and triphenyltin (TPT) are the most toxic.
The heavy metal content in inorganic pigments is more obvious, such as lead, chromium yellow, molybdenum, chromium red, etc., and we can use iron red and iron yellow, titanium nickel yellow, bismuth vanadate yellow and other inorganic pigments and some organic pigments to replace. When some organotin catalysts enter the human system, they can cause damage to the hepatobiliary system and nervous system. Therefore, tin-containing catalysts should be used carefully in the production process of powder coatings.
The current requirements for green coatings are mainly manifested in two aspects: on the one hand, reducing VOC emissions in the production and construction process of coatings, and reducing the environmental hazards caused by volatilization;
On the other hand, the total amount of organic matter should be reduced while the toxicity of organic matter should be controlled, so as to avoid causing harm to relevant personnel in the process of production, construction and long-term use. Since the powder coating consists of 100 % solids, it can achieve zero VOC emissions. Therefore, the development of green powder coatings also needs to do the following:
1) Limit the addition of organotin as a catalyst for powder coatings containing polyester resins and its antibacterial and antifungal functional powder coatings as antimicrobial agents
2) Avoid using raw materials containing heavy metals;
3) There is also safe, efficient and clean production management. To do the above points, the pace of "paint to powder" will be faster, and the green road of powder coating will be broader.