Based on the previously discussed shelf lives and storage requirements for various types of antifouling raw materials, direct use of expired materials is generally not recommended. The specific assessment and associated risks are outlined below:
Key risks of direct use
Once expired, the active antifouling ingredients may decompose or settle, leading to a significant reduction or total loss of antifouling performance and a failure to achieve the intended anti-adhesion or soil-repellent effects. Certain types of materials may also generate toxic or hazardous substances, posing safety risks; improper disposal would also violate regulations under the Law on the Prevention and Control of Environmental Pollution by Solid Waste.
Rare exceptions for downgraded use
Only specific basic antifouling raw materials-characterized by low concentrations and minimal performance degradation-may be downgraded for use in non-critical, low-requirement applications, provided that professional testing confirms key parameters remain within permissible limits. Direct use in formal production processes is strictly prohibited.
Compliance requirements for disposal
Most expired antifouling raw materials are classified as hazardous waste. They must be categorized, logged, and handed over to a qualified professional hazardous waste management company for compliant disposal; arbitrary discarding is strictly prohibited.
