A Declaration of Conformity Covering Only the Base Polymer
Base polymer declarations certify monomer purity at the reactor gate but omit all converter additives, breakdown products, and finished article migration limits.
Hinders Amine Light Stabilizers
Meaning
Chemical additives added to polymer formulations protect the plastic material from degradation caused by exposure to ultraviolet radiation and oxygen. These compounds, known as hinders amine light stabilizers, work by scavenging the free radicals generated when the polymer chain is broken by ultraviolet light. Unlike ultraviolet absorbers, they do not absorb the incoming radiation but instead inhibit the subsequent chain-reaction degradation of the polymer.
This prolongs the useful life of outdoor moulded parts, such as automotive bumpers or agricultural films, by preventing embrittlement and discoloration, which maintains safety standards.
Radical Scavenging
Mechanism of action involves a continuous cycle of radical trapping and regeneration of the active stabilizer species. When the polymer is exposed to sunlight, it generates alkyl radicals that react with the stabilizer to form stable nitroxide radicals. This reaction halts the self-catalytic oxidation of the resin, protecting the mechanical properties of the moulded part.
The long-term performance depends on the concentration and molecular weight of the stabilizer in the resin.
Sourcing Cost
Sourcing resins pre-blended with these stabilizers increases the raw material cost but is essential for outdoor applications. Moulding companies must balance the cost of these additives against the risk of field failures and warranty claims. In high-exposure applications, utilizing these compounds is necessary to maintain the impact strength and flexibility of the polymer over several years.
Moulding Stability
High melt temperatures during the injection process can cause some low-molecular-weight stabilizers to volatilize or degrade in the barrel. This degradation can lead to plate-out on the mould surface, which creates a cosmetic defect or alters the surface texture of the parts. Moulding at the lower end of the recommended temperature window reduces this plate-out and preserves the stabilizer’s efficacy.