UV Absorbers for Plastics: 6 Chemical Classes, How They Work and Selection

UV absorbers are light stabilizers that absorb ultraviolet radiation between about 280 and 400 nm and release it as heat, and plastics contain them at 0.1-0.5 wt% (up to 10 wt% in co-extruded cap layers) to stop sunlight from yellowing and embrittling the polymer. Six chemical classes do this job, from benzotriazoles to benzoxazinones, so which one suits a clear polycarbonate sheet, a PVC profile or a PET bottle?

UV absorbers are one of the 3 main groups of light stabilizers among plastic additives, next to HALS and quenchers. Unlike HALS, they also shield what is inside a transparent pack, protecting the contents of a bottle or a blister as well as the polymer wall around them.

The hub on UV stabilizers for plastics compares UV absorbers with every other light-stabilizer class. This page covers the ESIPT mechanism, the 6 chemical classes and their grades, UV absorber and HALS synergy, 5 selection criteria, a polymer-by-polymer table, dosage, test standards, the SVHC, Annex XIV and Stockholm POP status of the restricted benzotriazoles, food-contact and drinking-water limits, and the manufacturers that supply the market.

In brief

• 280-400 nm: the ultraviolet window a UV absorber absorbs.
• 6 chemical classes of UV absorber are used in plastics.
• 0.1-0.5 wt%: typical benzotriazole UV absorber level in general plastics.
• 153 °C vs 333 °C: temperature of 1% weight loss, UV-P vs Tinuvin 360.
• 1 mg/kg: EU limit on UV-328 as a trace contaminant, from 4 August 2029.

What Are UV Absorbers?#

A UV absorber (UVA) is a plastic additive that absorbs the ultraviolet part of sunlight more strongly than the polymer and its impurities do, and converts that energy into harmless heat before it can break polymer bonds. Suppliers also call it a UV absorbent or an ultraviolet light absorber. "UV screener" properly belongs to UV-blocking pigments such as carbon black, and "UV filter" is the cosmetics-industry term for the same chemistry. UV absorbers form one of the light-stabilizer classes alongside HALS, quenchers, hindered benzoates and UV-screening pigments, and each class protects a plastic part by a different route.

How do UV absorbers stop the photodegradation of plastics?#

UV absorbers stop the photodegradation of plastics by catching UV photons before the polymer's chromophores do: the absorbed energy moves a proton across an internal hydrogen bond, and the molecule returns to its ground state within picoseconds, releasing the energy as heat. Sunlight reaching the earth's surface cuts off at about 280-290 nm, and aliphatic polyolefins such as polypropylene and polyethylene absorb almost nothing above about 250 nm on their own, so photo-oxidation starts instead at chromophores: hydroperoxides, carbonyl groups and catalyst residues left over from polymerisation. A UV absorber intercepts the photons that would otherwise excite those chromophores first.

The mechanism is excited-state intramolecular proton transfer (ESIPT), described for phenolic UV absorbers by J. Crawford in Progress in Polymer Science 24 (1999) 7-43. In benzotriazoles and hydroxyphenyl triazines the proton moves along an intramolecular O-H···N bond; in 2-hydroxybenzophenones it moves along an O-H···O=C bond instead. Cyanoacrylate UV absorbers dissipate the same energy by E/Z isomerisation rather than ESIPT.

The ESIPT cycle of a phenolic UV absorber runs in 4 steps:

1. Photon absorption raises the molecule to an excited singlet state.
2. Proton transfer moves a hydrogen atom across the hydrogen bond within picoseconds, forming an excited-state tautomer.
3. Radiationless decay returns the tautomer to its ground state, releasing the energy as heat rather than fluorescence.
4. Proton return regenerates the starting molecule for the next photon.

The chemistry of photodegradation of plastics differs by polymer, which is why UVA choice starts with the host resin.

Why does part thickness decide how well a UV absorber works?#

Part thickness decides how well a UV absorber works because UV absorbers follow the Beer-Lambert law: the fraction of light they absorb grows with concentration multiplied by path length, so the outermost micrometres of a part stay poorly protected. HALS do not share this limitation: their radical-trapping action is thickness independent, which is why thin films and fibres rely mainly on HALS while thick sections and clear packaging rely more on UV absorbers.

Coatings data illustrate the law numerically. Mayzo recommends 2.5-5% UV absorber on solids for a 10-20 µm dry film, 1.25-2.5% for a 20-40 µm film and 0.5-1.25% for a 40-80 µm film.

Illustration of Beer-Lambert behaviour (coatings data, Mayzo).

Plastics converters apply the same logic: co-extruded cap layers on polycarbonate and PVC sheet concentrate the UV absorber where light enters, at up to 0.2-10 wt% for Tinuvin 360 and 0.2-6 wt% for Tinuvin 1577.

Is a UV absorber the same as a UV stabilizer?#

No: a UV absorber is one type of UV stabilizer; "UV stabilizer" (or light stabilizer) is the umbrella term that also covers HALS, quenchers, hindered benzoates and UV-screening pigments. BASF and Syensqo catalogues use "light stabilizer" as the umbrella term, while "UV stabilizer" is the dominant search term buyers actually type, and HALS themselves are often marketed as "UV stabilizers" in trade usage even though they do not absorb UV.

What Are the 6 Classes of UV Absorbers for Plastics?#

The 6 classes of UV absorbers used in plastics are benzotriazoles (such as UV-P and UV-234), hydroxyphenyl triazines (UV-1577), 2-hydroxybenzophenones (UV-531), cyanoacrylates (octocrylene), oxanilides (Tinuvin 312) and benzoxazinones (Cyasorb UV-3638); benzotriazoles and hydroxyphenyl triazines cover most engineering and commodity plastics uses between them. Each class absorbs a different part of the 280-400 nm window and tolerates a different processing temperature, which is why formulators keep all 6 on the shelf.

Absorption ranges are supplier data (Mayzo, BASF technical data sheets) and differ by grade within a class.

1. Benzotriazole UV absorbers#

Benzotriazole UV absorbers are 2-(2-hydroxyphenyl)benzotriazoles that absorb strongly between 300 and 400 nm, and they are the most widely used UV absorber class in plastics, from UV-P in polystyrene to UV-234 in polycarbonate. BASF's chloroform-solution data give each grade a characteristic λmax and extinction coefficient: UV-P absorbs at 301 nm (ε 16,150 l/mol·cm), UV-326 at 312 nm (ε 15,600) and UV-329 at 301 nm (ε 15,910), each measured at 10 mg/l in chloroform. The chlorinated grades UV-326 and UV-327 are red-shifted relative to UV-P, and UV-326 gives less than 1% transmittance up to 370 nm.

Grades, volatility and regulatory status of all benzotriazole UV absorbers are compared on their own page. Formulators choose from UV-P, UV-326, UV-329 (Tinuvin 329), UV-234, UV-360, the liquid grade UV-571 and UV-928 (Tinuvin 928). Four of these grades, UV-320, UV-327, UV-328 and UV-350, carry EU restrictions, covered in the regulatory section further down this page.

Low-volatility vs classic benzotriazoles#

High-molecular-weight benzotriazoles such as UV-234 (447.6 g/mol) and the bis-benzotriazole UV-360 (658.9 g/mol) lose 1% of their weight only at 264 °C and 333 °C, while classic UV-P (225.25 g/mol) already loses 1% at 153 °C. Tinuvin 234 and UV-360 are the reference high-molecular-weight benzotriazoles for polycarbonate, PET and polyamide, processed at 280-320 °C, where the lighter grades would volatilise out of the melt.

2. Hydroxyphenyl triazine (HPT) UV absorbers#

Hydroxyphenyl triazine (HPT) UV absorbers such as Tinuvin 1577 and Cyasorb UV-1164 combine very high UV absorption with very low volatility, which makes them the standard choice for polycarbonate and polyesters processed near 300 °C. The class structure is 2-hydroxyphenyl-s-triazine, and UV-1577 absorbs strongly across 280-350 nm with very low chelation with catalyst residues, which suits it to filled, reinforced and flame-retarded compounds; it loses 1% of its weight only at 300 °C.

Every grade of hydroxyphenyl triazine UV absorbers is listed with its absorption range on the class page. UV-1577 (425.5 g/mol) is the workhorse grade, UV-1164 (509.7 g/mol) covers polyolefins and engineering plastics, and Tinuvin 1600 extends the family to PMMA. BASF's technical literature reports that HPTs outperform benzotriazoles and cyanoacrylates in polycarbonate, polyesters and PMMA, a supplier claim rather than an independent measurement.

3. 2-Hydroxybenzophenone UV absorbers#

2-Hydroxybenzophenone UV absorbers such as UV-531 (Chimassorb 81) are the classic UV absorber for polyolefin film and flexible PVC, though BASF positions them for applications where durability expectations are moderate. The class absorbs through the same ESIPT mechanism as benzotriazoles, along an O-H···O=C hydrogen bond rather than the O-H···N bond of benzotriazoles and triazines. Two grades dominate the market: UV-531 (octabenzone, CAS 1843-05-6), a light-yellow powder melting at 46.5-49 °C, and BP-3 (oxybenzone, UV-9, CAS 131-57-7). Absorption bands and the full grade list of benzophenone UV absorbers sit on their own class page.

UV-531 stays the standard UV absorber in polyethylene and EVA agricultural film thicker than 100 µm, combined with HALS at 0.15-0.5 wt% (BASF) or 0.1-0.7 wt% (Mayzo); its lower long-term photo-permanence next to hydroxyphenyl triazines is why BASF reserves it for moderate rather than decades-long outdoor exposure. BP-3 covers PVC, polystyrene, cellulosics and acrylics, and carries a US food-contact listing for semirigid and rigid acrylics under 21 CFR 177.1010.

4. Cyanoacrylate UV absorbers#

Cyanoacrylate UV absorbers such as Uvinul 3035 (etocrylene), Uvinul 3039 (octocrylene) and the tetrafunctional Uvinul 3030 dissipate UV energy by E/Z isomerisation and add no colour, which suits them to clear PVC, PC and PET. Etocrylene (CAS 5232-99-5) is used at 0.1-1.0 wt% in PVC, polyamide, polycarbonate, ABS, SAN, ASA, PS and polyurethane. Octocrylene (CAS 6197-30-4) is a liquid grade absorbing 280-320 nm at a maximum of 306 nm, dosed at 0.1-1.0 wt% in flexible PVC, plastisols, polyurethane, polyesters and PMMA. Uvinul 3030 (CAS 178671-58-4, 1,061.1 g/mol), compared with the others under cyanoacrylate and oxanilide UV absorbers, is tetrafunctional and colourless, used at 0.2-10 wt% in PET and PC including co-extrusion layers.

5. Oxanilide UV absorbers#

Oxanilide UV absorbers, represented by Tinuvin 312, absorb mainly UV-B and do not react with metal ions, which is why polyamides that carry copper heat stabilizers use them. Tinuvin 312 (2-ethoxy-2'-ethyloxanilide, CAS 23949-66-8; also Hostavin VSU, Sanduvor VSU, SONGSORB 3120, BLS 1312) absorbs strongly at 250-350 nm, does not discolour the melt, has no reactivity with alkalines and is compatible with optical brighteners and copper-based heat stabilizers.

Tinuvin 312 is covered with the other oxanilide UV absorbers on the cyanoacrylate page, dosed at 0.05-0.5 wt% (Mayzo) or 0.10-1.0 wt% (BASF) in polyamides, polyesters, PVC and polyurethanes, the polymer families where oxanilides are typical.

6. Benzoxazinone UV absorbers#

Benzoxazinone UV absorbers are represented by one commercial grade, Cyasorb UV-3638, a colourless UV-A absorber that withstands 350 °C for short periods and protects the contents of PET bottles and films. Cyasorb UV-3638 (CAS 18600-59-4) melts at 310-320 °C and stays heat stable to 350 °C short-term and 160 °C long-term, per Mayzo. It is dosed at 0.1-10 wt% in PET, PBT, PC, PA, PPO and PETG; Mayzo states a typical loading runs to about one third of the equivalent benzotriazole dosage. It carries an EU specific migration limit of 0.05 mg/kg including hydrolysis products, and protects PET bottles, film, fibre and PC capstock.

Are hindered benzoates and formamidines UV absorbers?#

Hindered benzoates such as Cyasorb UV-2908 start as radical scavengers and only become benzophenone-type UV absorbers after a photo-Fries rearrangement in light, so they are classed as HALS synergists rather than UV absorbers. A separate formamidine UV absorber (CAS 57834-33-0) is used in polyurethane and epoxy at 0.5-3.0 wt% on solids together with 0.5-2.0% HALS, per Mayzo.

How Do UV Absorbers Work with HALS?#

UV absorbers and HALS work together because they protect different zones: the UV absorber filters light in the bulk of a thick or clear part and shields packaged contents, while HALS trap the radicals that still form at the surface, where a UV absorber is too thin to help. This division of labour follows from the Beer-Lambert dependence of UV absorbers: their protection grows with concentration times path length, so the outermost surface of any part stays under-protected no matter the loading, while HALS protection does not depend on thickness at all. HALS do not absorb UV light; they trap the radicals that photo-oxidation generates and regenerate through the Denisov cycle instead of being consumed, which is why a small HALS loading keeps working for years. Basic HALS are deactivated by acids, such as the HCl that PVC releases, while UV absorbers are not.

BASF's technical data sheets for its HALS grades, including Chimassorb 944, Tinuvin 622 and Tinuvin 783, recommend adding a UV absorber of the Tinuvin 326 or Chimassorb 81 type in unpigmented articles. UV-326 in polypropylene, for example, is dosed at 0.1-0.5 wt% specifically for use with HALS. Grades and basicity of hindered amine light stabilizers (HALS) sit on the HALS page.

How to Choose a UV Absorber: 5 Selection Criteria#

A UV absorber is chosen by 5 criteria: its absorption range and extinction coefficient, its volatility at the processing temperature, its colour and interaction with metal ions, its photo-permanence and its physical form and compatibility with the polymer. BASF names absorbance, photo-permanence and volatility as its 3 core factors; colour interaction and physical form round out the practical checklist.

1. Absorption range and extinction coefficient#

The absorption range of a UV absorber must cover the wavelengths that damage its host polymer: red-shifted benzotriazoles such as UV-326 block light up to 370 nm, while oxanilides and octocrylene absorb mainly in the UV-B below 320-350 nm. PET absorbs from about 360 nm and strongly below 320 nm, PC degrades through photo-Fries rearrangement, and PVC absorbs nothing above 220 nm, so a UV absorber's window should cover the polymer's own weak point. UV-1577 covers 280-350 nm, Tinuvin 312 covers 250-350 nm (UV-B), octocrylene covers 280-320 nm at 306 nm maximum, and UV-3638 is a strong UV-A absorber, so the 6 classes together span the full 280-400 nm window.

2. Volatility and processing temperature#

Volatility sets the upper processing temperature of a UV absorber: UV-P loses 1% of its weight at 153 °C, whereas Tinuvin 1577 holds out to 300 °C and UV-360 to 333 °C, which is why polyester and polycarbonate compounders use the heavier grades. Tinuvin 1600 has a vapour pressure below 0.1 pPa, and UV-3638 stays heat stable to 350 °C for short exposures. PET, PBT and PEN, processed at 270-300 °C, need Tinuvin 1577, Tinuvin 1600, UV-234, Uvinul 3030 or UV-3638; lighter benzotriazoles would flash off in the melt.

TGA at 20 °C/min in air (BASF technical data sheets).

3. Colour, metal ions and chelation#

UV absorbers can discolour a part when they bind metal ions: UV-P forms coloured complexes with iron and cobalt, while hydroxyphenyl triazines such as Tinuvin 1577 barely chelate and suit filled, reinforced and flame-retarded compounds. Tinuvin 312 does not interact with metals and has no reactivity with alkalines. Uvinul 3030 and Uvinul 3035 add no inherent colour, while UV-326 and UV-531 are light-yellow powders, an appearance factor that matters in water-clear applications.

4. Photo-permanence#

Photo-permanence, the ability of a UV absorber to survive its own light exposure, separates the classes: BASF rates benzophenones for moderate durability, and positions hydroxyphenyl triazines above benzotriazoles and cyanoacrylates in polycarbonate and polyesters. A UV absorber that degrades faster than the polymer it protects loses its function early, which is why photo-permanence ranks alongside absorbance and volatility among BASF's 3 criteria. No numeric half-lives exist for any class, only this relative ranking.

5. Physical form, compatibility and migration#

The physical form of a UV absorber decides how it is dosed and how well it stays in the polymer: liquid grades such as UV-571 and octocrylene blend into polyurethane and plasticised PVC, while powders such as UV-360 suit engineering-plastic compounding. UV-571 melts at minus 56 °C and is miscible above 50 g/100 g with hexane, acetone and toluene; octocrylene melts at minus 8 °C. The models behind additive migration in plastics explain why low-molecular-weight UV absorbers carry lower EU migration limits: Tinuvin 1577 is capped at 0.05 mg/kg while the smaller, more mobile Tinuvin 312 is capped at 30 mg/kg.

Which UV Absorber Suits Each Polymer?#

The right UV absorber depends on how the host polymer degrades and how hot it is processed: polyolefins pair a benzotriazole or benzophenone with HALS, PVC relies on UV absorbers because HCl disables basic HALS, and polycarbonate and PET need low-volatility triazines, UV-360 or UV-3638. The table below lines up each major plastics family against its degradation driver, UV absorber classes, named grades and typical dosage.

Supplier TDS ranges; trials decide the final level. FDA limits (see the food-contact section below) are legal maxima, not dosages.

Polyolefins: UV absorbers for polypropylene and polyethylene#

Polypropylene and polyethylene use UV absorbers mainly as partners to HALS: UV-326 at 0.1-0.5 wt% or UV-531 at 0.1-0.7 wt% is added when the part is unpigmented or the film is thicker than 100 µm. Polypropylene is the most light-sensitive commodity polyolefin because its tertiary C-H bonds oxidise readily, so unpigmented PP moulding and fibre typically pairs a UV absorber with a HALS rather than relying on HALS alone. Dosage and pairing details for UV stabilizers for polypropylene extend this into every PP application.

Polyethylene and EVA follow the same pattern at slightly lower UV-326 levels, 0.1-0.4 wt%, and agricultural film over 100 µm combines UV-531 with HALS. Cap-layer and film grades are on UV stabilizers for polyethylene.

PVC#

PVC depends more on UV absorbers than any other commodity plastic because the HCl it releases deactivates conventional HALS, so profiles, films and plastisols use benzotriazoles such as UV-571, benzophenones, oxanilides or cyanoacrylates. Pure PVC absorbs nothing above 220 nm, and degradation begins instead at structural defects; once 8 or more conjugated C=C double bonds form, the polymer visibly discolours. HCl protonates the basic nitrogen of conventional N-H and N-CH3 HALS, though NOR HALS and low-basicity oligomers such as Uvinul 5050 H are exceptions.

Liquid UV-571 at 0.3-0.5 wt% (up to 5 wt% in co-extruded cap layers), Tinuvin 312, Uvinul 3035 and Uvinul 3039 all see use in PVC window profiles, films and plastisols, usually alongside rutile TiO2. Why HALS fail in PVC is explained on UV stabilizers for PVC.

Polycarbonate and PMMA#

Polycarbonate needs high-performance UV absorbers because it degrades by photo-Fries rearrangement under UV, so sheet makers concentrate Tinuvin 360, Tinuvin 1577 or UV-234 in a co-extruded cap layer at up to 6-10 wt%. Cap-layer loadings are detailed on UV stabilizers for polycarbonate: Tinuvin 360 runs 0.2-1.0 wt% in the bulk and up to 10 wt% in cap layers, Tinuvin 1577 runs 0.2-6 wt%, and UV-234 runs 0.15-0.60 wt%. BASF's highest cap-layer loadings allow direct two-layer co-extrusion without a neutral third top layer.

PMMA is inherently UV stable, transmitting about 92% of light at 3 mm, so its UV absorbers protect the surface finish and any packaged contents rather than the polymer itself. UV-P, UV-234, UV-360 and octocrylene all see use in PMMA glazing, covered on UV stabilizers for PMMA (acrylic).

PET and other polyesters#

PET and other polyesters use UV absorbers both to protect the polymer, which absorbs UV from 360 nm, and to protect bottle and film contents, and only grades that survive 270-300 °C processing qualify: Tinuvin 1577, UV-234, Uvinul 3030 and Cyasorb UV-3638. PET degrades mainly by Norrish type I photolysis, with Norrish type II side reactions yielding acetaldehyde that can taint packaged food or drinks. Bottle and fibre packages are on UV stabilizers for PET. UV-234 and UV-1577 are each capped at 0.5 wt% in PET under FDA rules, and UV-3638 carries an EU migration limit of 0.05 mg/kg including hydrolysis products.

Polyamides and polyurethanes#

Polyamides use oxanilide UV absorbers such as Tinuvin 312 because they leave copper heat stabilizers untouched, while polyurethanes and TPU take the liquid benzotriazole UV-571 at 0.2-0.5 wt%. PA6 and PA66 compounds that use copper-based heat stabilizers can add Tinuvin 312 without a compatibility conflict, and UV-234 serves as a high-temperature alternative, both covered on UV stabilizers for nylon.

Aromatic polyurethane yellows readily under UV, and TPU and PU foams take the liquid UV-571 grade because it blends directly into the polyol or melt. Foam and TPU packages are on UV stabilizers for polyurethane and TPU.

Styrenics: ABS, PS and SAN#

ABS, polystyrene and SAN combine a benzotriazole UV absorber such as UV-P (0.1-0.5 wt%) or UV-234 with a low-molecular-weight HALS to slow the yellowing that polyenes and oxidised butadiene cause. Polystyrene yellows through polyene formation and acetophenone-type chromophores, while ABS yellowing traces to oxidation of the butadiene phase. Uvinul 3035 also sees use in ABS, SAN, ASA and PS at 0.1-1.0 wt%, and UV-P is capped at 0.25 wt% in PS and rubber-modified PS for non-alcoholic food contact under FDA rules. Butadiene-phase protection is covered on UV stabilizers for ABS.

How Much UV Absorber Is Used in Plastics?#

Most plastics contain 0.1-0.5 wt% UV absorber, and co-extruded cap layers on polycarbonate or PVC sheet carry 5-10 wt% because the absorber is concentrated in the thin layer facing the sun. UV-531 reaches up to 0.7 wt%, and cyanoacrylates run 0.1-1.0 wt%. Four factors drive the exact dosage:

• Part thickness, following the Beer-Lambert relationship between concentration and path length.
• Whether the part is clear or pigmented, since pigments such as carbon black and titanium dioxide already screen some UV.
• Processing temperature, which sets the volatility ceiling a grade must clear.
• Service conditions and regulatory caps, including the FDA and EU limits covered later on this page.

Most converters add UV absorbers as UV masterbatch rather than as powder, since a masterbatch disperses the additive evenly and avoids handling fine powder on the floor. A worked example shows the arithmetic: a 10 wt% UV-absorber masterbatch let down at 3% gives 0.10 x 3% = 0.3 wt% UV absorber in the finished part, inside the general 0.1-0.5 wt% range. Check the arithmetic in the let-down ratio calculator.

FDA caps under 21 CFR 178.2010 are legal maxima, not recommended dosages: a 3.0 wt% ceiling for UV-234 in polycarbonate is not a target loading.

How Are UV Absorbers Tested in Plastics?#

UV absorbers are tested twice: the additive itself by its UV absorbance (λmax and extinction coefficient in solution), and the stabilized plastic by accelerated weathering to ISO 4892-2 or ASTM G154, with yellowness index, colour change and carbonyl index tracked over time. Absorbance is measured in chloroform solution at 10 mg/l, the method behind the λmax and ε values given for each class earlier on this page.

4 properties of the weathered plastic are tracked:

• Yellowness index, measured by ASTM E313-20 (R2025), never the withdrawn ASTM D1925.
• Colour difference, measured by ASTM D2244-25.
• Carbonyl index, measured by FTIR as a marker of photo-oxidation.
• Mechanical retention, such as elongation at break or impact strength, after a fixed exposure time.

How ASTM E313 calculates the yellowness index of a weathered plaque is explained on its own page. Cycle details and lamp types are on accelerated weathering tests: ISO 4892-2 Method A cycle 1 runs 102 minutes of xenon light and 18 minutes of water spray at 0.51 W/(m2·nm) at 340 nm, BST 65 ± 3 °C; ASTM G154-23 cycle 4 runs 8 hours of UVA-340 light at 70 °C followed by 4 hours of condensation at 50 °C, per ASTM D4329-26.

Laboratory weathering reproduces UV, heat and moisture, but not airborne pollution, biological attack or salt-water exposure, so a chamber pass does not guarantee every outdoor microclimate.

Which UV Absorbers Are Restricted? SVHC, Annex XIV and POPs Status of Benzotriazoles#

Six benzotriazole UV absorbers are regulated in the EU: UV-328 is a global POP, UV-320, UV-327 and UV-350 need REACH authorisation since 27 November 2023, and UV-326 and UV-329 have been SVHCs since 23 January 2024. All six are tracked under benzotriazole UV absorbers: SVHC, Annex XIV and POPs status, which extends the table below with the full evidence trail.

Annex XIV entries 51-54 added by Commission Regulation (EU) 2020/171 (6 Feb 2020); latest application date 27 May 2022; no exempted uses. Status checked 22 Sep 2026.

UV-328: Stockholm POP and EU POPs limits#

UV-328 has been a persistent organic pollutant under Annex A of the Stockholm Convention since decision SC-11/11 in May 2023, the first non-halogenated plastic additive to be listed. UV-328 (Tinuvin 328) carries an aircraft-only use exemption under decision SC-12/14 (COP-12, 2025), which expires at the end of 2030. The EU implemented the listing through Delegated Regulation (EU) 2025/843, adopted 5 May 2025, published 15 July 2025 and in force from 4 August 2025.

The EU trace-contaminant limit steps down in 3 stages: 100 mg/kg from 4 August 2025, 10 mg/kg from 4 August 2027 and 1 mg/kg from 4 August 2029. Derogations end 4 August 2030, and spare parts may remain in service until end of life or 31 December 2043 (aircraft spare parts 31 December 2030). UV-328 joins PBDEs and HBCD among POPs in plastics, though the Stockholm Convention sets a separate 2044 cap for replacement parts, never to be confused with the EU's 2043 deadline.

UV-320, UV-327 and UV-350: REACH Annex XIV authorisation#

UV-320, UV-327 and UV-350 cannot be used in the EU without REACH authorisation since their sunset date of 27 November 2023, and no uses are exempted. Commission Regulation (EU) 2020/171 (6 February 2020) added the 3 grades to Annex XIV as entries 52 (UV-327), 53 (UV-350) and 54 (UV-320), alongside UV-328 as entry 51, all with a latest application date of 27 May 2022. Sunset dates for every additive on the REACH Annex XIV authorisation list follow the same pattern.

A restriction on the presence of these three substances in articles is in preparation, following an ECHA screening report published 18 January 2024, and has not been adopted. UV-327 remains listed as FCM 469 in EU 10/2011 even though its EU use now needs authorisation.

UV-326 and UV-329: SVHC and the Annex XIV recommendation#

UV-326 and UV-329 have been Substances of Very High Concern since 23 January 2024 because they are very persistent and very bioaccumulative, and ECHA's draft recommendation of 2 February 2026 proposes adding them to the REACH authorisation list. Tinuvin 326 (UV-326) remains listed for EU food contact despite its SVHC status: it is FCM 470 under group restriction 12, SML(T) 30 mg/kg, and FDA-listed at up to 0.5 wt% in olefin polymers. UV-329 carries a similar FDA allowance, up to 0.5 wt% in polycarbonate under conditions E, F and G.

Article 33 duties start once a substance joins the SVHC Candidate List. Neither grade is on Annex XIV as of this page's review date, and ECHA's consultation on the draft recommendation closed 2 May 2026 with the outcome still pending.

Which UV absorbers replace restricted benzotriazoles?#

Formulators replace restricted benzotriazoles with 5 alternatives: the high-molecular-weight benzotriazoles UV-234 and UV-360, hydroxyphenyl triazines such as Tinuvin 1577 and Cyasorb UV-1164, and cyanoacrylates.

• High-molecular-weight benzotriazoles UV-234 and UV-360, unrestricted and clearing 1% weight loss above 260 °C.
• Hydroxyphenyl triazines Tinuvin 1577, Tinuvin 1600 and Cyasorb UV-1164, combining low volatility with very low chelation.
• Cyanoacrylates such as Uvinul 3030, colourless and unrestricted.
• UV-928, positioned by suppliers as a non-SVHC replacement for UV-328 in coatings, outside this page's plastics scope.
• UV-234 itself, under ECHA PBT assessment (opened 5 September 2025), a status distinct from SVHC.

Which UV Absorbers Are Allowed in Food Contact and Drinking Water?#

Food-contact plastics may contain only UV absorbers listed in Regulation (EU) No 10/2011, within each substance's specific migration limit, or in US 21 CFR 178.2010, within each polymer's weight limit, which excludes UV-328 in both systems and UV-329 in the EU. The EU regulation sets an overall migration limit of 10 mg/dm2 and a generic specific migration limit of 60 mg/kg for any substance without its own listed limit. See the full list of additives for food packaging by function.

EU 10/2011 and FDA 21 CFR 178.2010 limits for UV absorbers#

Tinuvin 1577 shows how far the two systems differ: the EU allows it to migrate at only 0.05 mg/kg of food (FCM 770), while the US caps it at 0.5 wt% of polycarbonate, polyester elastomers or PET (21 CFR 178.2010). The table below lists the CAS number, EU listing and FDA cap for every UV absorber named on this page.

FDA limits are maximum use levels, not recommended dosages. "not established" means no verified FDA entry was found; it is not the same as a confirmed "not listed". EU entries checked against the consolidated text of 14 Jul 2026.

SML, OML and group restrictions are explained on EU 10/2011: benzotriazoles UV-P, UV-327 and UV-326 share group restriction 12 (combined SML(T) 30 mg/kg), and benzophenones UV-531 and BP-3 share group restriction 8 (combined SML(T) 6 mg/kg). Food types and conditions of use are decoded on 21 CFR 178.2010, which sets per-polymer weight-percent caps rather than a migration limit.

Drinking-water contact#

Plastic parts in contact with drinking water in the EU may use UV absorbers from the European positive list under Directive (EU) 2020/2184, which includes Tinuvin 1577 (entry 0677), UV-234 (0646) and Cyasorb UV-1164 (0389). The list also covers UV-P (0381), UV-326 (0406), UV-327 (0405), Tinuvin 312 (0547), Uvinul 3030 (0685), UV-3638 (0701), BP-3 (0261) and UV-531 (0368). US and German rules are compared on plastic additives in drinking-water contact.

Who Are the Main UV Absorber Manufacturers?#

UV absorbers for plastics come from BASF (Tinuvin, Chimassorb and Uvinul), Syensqo (Cyasorb), Songwon (SONGSORB), Mayzo (BLS), Everlight (Eversorb) and Clariant (Hostavin), and the same benzotriazole or benzophenone is often sold under 5 or more names. Plants, grades and certifications by company are in the directory of UV stabilizer and HALS manufacturers. BASF built its current portfolio partly through its 2009 acquisition of Ciba. Syensqo, which carries Cyasorb, was spun off from Solvay and listed independently on 11 December 2023. Songwon describes itself as the world's second-largest polymer stabilizer maker, a company claim rather than an independently verified ranking; Rianlon, founded in Tianjin in 2003, also carries UV absorbers.

Because so many trade names map to the same CAS number, buyers should compare UV absorbers by CAS number and food-contact status, not by trade name. Check any other grade in the plastic additive trade name lookup.

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What Other Light Stabilizers Protect Plastics Besides UV Absorbers?#

Besides UV absorbers, plastics are protected by UV-screening pigments, nickel quenchers and hindered benzoates, and above all by HALS, which trap radicals instead of absorbing light. All types of UV stabilizers for plastics are compared on the hub, which ranks each class by mechanism, thickness dependence and typical dosage.

UV screeners: carbon black, titanium dioxide and zinc oxide#

UV screeners are pigments that block light at the surface instead of dissolving in the polymer: carbon black absorbs UV across the solar spectrum, and rutile titanium dioxide and zinc oxide absorb and scatter it. Pigment loadings are compared on UV screeners. Carbon black is the most effective UV screen for polyethylene and polypropylene.

Grades and particle sizes are on carbon black in plastics. Copper phthalocyanine also absorbs UV, but it can act as a photoinitiator rather than a protectant in some formulations.

Nickel quenchers#

Nickel quenchers such as UV-1084 deactivate excited molecules after light has been absorbed rather than absorbing it themselves, and they survive today mainly in agricultural film. UV-1084 (CAS 14516-71-3, MW 572.5) removes energy from excited chromophores and singlet oxygen by Förster energy transfer and releases it as heat. It falls under the REACH Annex XVII group entry for nickel and its compounds and is not listed in EU 10/2011.

UV absorbers outside plastics: coatings and sunscreens#

The same UV absorber chemistry also protects paints and skin: coatings use benzotriazoles and triazines such as Tinuvin 384-2 and Tinuvin 400, and sunscreens use benzophenone-3 and octocrylene under EU cosmetics limits. A clear coat typically carries 1.0-1.5% UV absorber plus 0.5-1.0% HALS, for a dry film thickness of about 40 µm.

Its plastics uses are on benzophenone-3 (oxybenzone): EU cosmetics rules cap it at 6% in face, hand and lip products, 2.2% on the body and 0.5% elsewhere, under Regulation (EU) 2022/1176 (applicable 28 January 2023), and octocrylene is capped at 10% (9% in propellant sprays).

What materials absorb UV light?#

In plastics, UV light is absorbed by dissolved UV absorbers such as benzotriazoles, by pigments such as carbon black and titanium dioxide, and by the aromatic rings of polymers such as PET, which absorbs from 360 nm. Aliphatic polyolefins absorb comparatively little UV on their own, below about 250 nm, which is why added UV absorbers matter so much for those materials specifically.

What is the best UV absorber for plastic?#

No single UV absorber is best for every plastic: UV-326 or UV-531 with HALS suits polyolefins, Tinuvin 1577 or UV-360 suits polycarbonate and PET, and Tinuvin 312 suits polyamides. The right choice always depends on the polymer's degradation route, its processing temperature and whether the part is clear or pigmented, the same 3 factors that structure the polymer-selection table earlier on this page.

Do UV absorbers wear out?#

UV absorbers are lost slowly over a part's service life, mainly by evaporation during processing, migration and extraction, and more slowly by their own photo-degradation, which is lower for triazines than for benzophenones. Volatility during processing, covered above, sets how much is lost before the part even enters service.

Are UV absorbers toxic?#

Most UV absorbers used in plastics carry no EU harmonised hazard classification; the regulatory concern with benzotriazoles is persistence in the environment, which made UV-328 a POP and UV-326 and UV-329 very persistent, very bioaccumulative SVHCs. UV-P, UV-326, UV-329, UV-234, UV-531, Tinuvin 312, UV-1164 and Uvinul 3030 carry no EU harmonised classification at all. Tinuvin 1577, UV-360 and UV-571 carry a harmonised Aquatic Chronic 4 (H413) classification, and UV-3638 carries Skin Sens. 1 (H317) in addition to H413.