Chemical Connections UK Contract Chemical Manufacturing

Antioxidants and stabilisers protect polymers and other formulated products against oxidative, thermal and UV-driven degradation, extending service life and preventing discolouration, embrittlement or loss of performance over time. Hindered phenolic antioxidants are among the most widely used, often combined with UV absorbers and hindered amine light stabilisers for comprehensive protection.

Key points

  • Hindered phenolic antioxidants interrupt the auto-oxidation chain reaction that degrades polymers, protecting against thermal and oxidative degradation during processing and use.
  • UV absorbers and hindered amine light stabilisers (HALS) protect specifically against light-induced degradation, complementing rather than replacing antioxidants.
  • Combining antioxidants with UV stabilisers is a common approach to long-term polymer stabilisation, since each addresses a different degradation mechanism.
  • Stabiliser choice and dosage affects a product's shelf life and in-service durability, particularly for polymer and coating products exposed to heat or sunlight.

How Antioxidants Are Used in Manufacturing

Antioxidants and stabilisers are incorporated during liquid chemical blending or powder blending, relevant across resins and polymers and coatings and paints where long-term durability is a performance requirement.

What They Protect Against

Antioxidants and stabilisers exist to slow degradation, and different types address different degradation routes. Oxidation, driven by atmospheric oxygen and accelerated by heat and by trace metals, is the most common and is addressed by antioxidants. Ultraviolet light causes its own degradation, addressed by UV absorbers and light stabilisers. Thermal stabilisers protect materials during high-temperature processing.

Because the mechanisms differ, a product exposed to several of them may need more than one type, and adding the wrong one gives no protection at all. Establishing what a product is actually exposed to - sunlight, heat, air, metal contact - is the starting point for selecting a stabiliser package rather than choosing from a category.

Practical Points

Antioxidant systems frequently work better in combination than alone, with different components interrupting the degradation chain at different points, so commercial stabiliser packages are often blends rather than single materials. Substituting one blend for another is therefore not a simple equivalence exercise.

Stabilisers are also consumed as they work, which is what sets the practical limit on protection. This is why accelerated ageing gives a useful indication but real-time stability testing remains necessary - the rate at which a stabiliser depletes at elevated temperature does not scale predictably to ambient conditions. Where oxidation is catalysed by trace metals picked up from equipment or raw materials, chelating agents are often used alongside antioxidants to bind those metals rather than relying on the antioxidant alone.

Regulatory Status by Application

Permitted stabilisers vary by application, particularly for food-contact, cosmetic and medical uses, and a material acceptable in an industrial product may not be permitted in a consumer one. Where a product may extend into a new application, confirm the stabiliser package remains acceptable rather than assuming the formulation transfers - it is a common reason a product cannot simply be repositioned.

Questions to Ask a Manufacturer

  • What antioxidant and stabiliser systems do you have experience formulating with?
  • How do you verify a stabiliser package protects against the specific degradation risks our product will face?
  • Can you test or predict shelf-life and in-service durability for a stabilised formulation?
  • Do you combine antioxidants with UV stabilisers where our product needs both types of protection?

Frequently Asked Questions

Do antioxidants and UV stabilisers do the same job?

No - antioxidants protect against thermal and oxidative degradation, while UV stabilisers and absorbers protect specifically against light-induced damage. Many products need both, addressing different degradation mechanisms.

Is more stabiliser always better for shelf life?

Not necessarily - dosage is a formulation decision balancing protection, cost and other performance properties, and should be validated through stability testing rather than maximised by default.

Find a Manufacturer

Find a UK Contract Chemical Manufacturer

Search the directory of UK contract and toll manufacturers by process, industry and capability.

Search the Directory

Last reviewed: August 2026. Regulation and guidance change — verify anything you rely on against the primary source. Tell us if something here is out of date.