At present, China's interior coated steel drums for food and agricultural products generally include honey buckets, juice buckets, and ketchup buckets. If the inner coating drum used for containing these foods, the hygienic quality of the inner wall paint fails to meet the safety food hygiene requirements, it will cause secondary pollution to the food, thereby affecting the intrinsic quality of the product. According to experts from the China Epoxy Resin Industry Association, polyamide epoxy resin coatings are epoxy resin coatings, and epoxy resin coatings are also cured film coatings. Epoxy resins are generally formed by the polymerization of bisphenol A (diphenol propane) and epichlorohydrin. According to the degree of polymerization, the molecular weight of the epoxy resin is also different. From the hygienic point of view, the larger the molecular weight, the smaller the epoxy value. The more stable it is, the less likely it is for harmful substances to dissolve into the food, and therefore the higher its safety. As a curing agent for a polyamide epoxy resin coating, polyamide itself is a high molecular compound, and no report of its toxicity has been found. Polyamide Epoxy Resin Quality The epoxy resin epoxy value is closely related to the curing agent ratio and degree of cure. The proper proportion of curing agent and the higher the degree of curing, the less uncured material in the epoxy resin coating migrates into the food. According to the provisions of GB9686-88 “Sanitary Standard for Polyamide Epoxy Resin Coatings on Inner Walls of Food Containersâ€, the evaporation residue of polyamide epoxy coating in various solvents should be controlled below 30 mg/L.
Perchloroethylene paint uses vinyl chloride resin as raw material, together with plasticizer, and is naturally dried and filmed after being painted or sprayed on the inner wall of the packaging drum. Perchloroethylene coatings are generally divided into primers and topcoats. Perchloroethylene resin contains vinyl chloride monomer, which is a carcinogenic and toxic compound. The vinyl chloride coating after film formation may still contain residual vinyl chloride. According to GB7105-86 "Hygienic Standards for Perchloroethylene Inner Wall Coating of Food Containers", the residual vinyl chloride monomer in the vinyl chloride coating after film formation should be controlled. 1 mg/kg or less. Organic fluorine coatings include polyvinyl fluoride, polytetrafluoroethylene, and polyhexafluoropropylene coatings. These coatings are polymerized with vinyl fluoride, tetrafluoroethylene, and hexafluoropropylene as the main raw materials, and are sprayed with certain additives on the packaging barrels. Inner wall surface. The organic fluorine coating has the characteristics of anti-sticking and corrosion resistance, but its acid resistance is poor, so it is widely used in inner coating drums containing honey.
In recent years, China's exports of fruit juices, ketchup, and honey have often been returned overseas due to excessive pesticide levels. As a food packaging drum, the residual amount of solvent on the inner wall should be as low as possible. Therefore, in the production of food packaging bucket, must be in accordance with the requirements of food safety and hygiene, to ensure that the cleaning of food packaging barrels and residual pesticide content does not exceed the health standards. Experts from the China Epoxy Resin Industry Association stated that an interlocking supervision system should be formed. Enterprises using food packaging barrels must obtain the food safety and health inspection report of the packaging barrels from the packaging barrel manufacturers; the packaging barrel production enterprises should supply coatings suppliers. Request food safety and sanitation inspection report for inner wall paint. At the same time, relevant departments should also regularly supervise and inspect food packaging barrels and issue inspection reports.