UV-329 (Tinuvin 329, Octrizole, UV-5411): Properties, Uses and SVHC Status

UV-329 (octrizole, CAS 3147-75-9) is a hydroxyphenyl benzotriazole UV absorber used at 0.1 to 0.5 wt% to protect polycarbonate, polyesters, PVC, styrenics and acrylics from sunlight. Because the same molecule has been on the REACH Candidate List since 23 January 2024, the practical question for a compounder is no longer how well it works but what its listing obliges.

UV-329 has been on the REACH Candidate List as a substance of very high concern since 23 January 2024, on very persistent and very bioaccumulative (vPvB) grounds under Article 57(e) of Regulation (EC) No 1907/2006. It is not on the REACH Annex XIV authorisation list, but ECHA named it in a draft Annex XIV recommendation published 2 February 2026, whose public consultation closed 2 May 2026. In the United States, the FDA allows up to 0.5 wt% in polycarbonate. UV-329 is one of 44 UV stabilizer pages in our directory of plastic additives, each built to the same identity, dosage and regulatory fields.

This page covers UV-329's identity and its three trading names, the excited-state proton-transfer mechanism that makes it a UV absorber, its physical and chemical properties, the dosage it takes in each polymer family, five application areas, how it performs against six other benzotriazole and triazine absorbers, how it interacts with HALS and pigments, its full regulatory matrix, its health and environmental profile, six named alternatives and the suppliers that produce it.

What Is UV-329 (Octrizole)?#

UV-329 is a 2-(2-hydroxyphenyl)benzotriazole carrying a branched tert-octyl group, which is the structural feature that makes it soluble in non-polar polymers and resistant to loss during processing. The systematic name is 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, also written as 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, and the molecule has the formula C20H25N3O at a molecular weight of 323.4 g/mol.

As an absorber rather than a radical scavenger, UV-329 sits in one of the two halves of the UV stabilizers for plastics family: it works by intercepting ultraviolet photons before they strike a chromophore, rather than by mopping up the radicals that photo-oxidation produces once light has already been absorbed. No synthesis route for the commercial grade is recorded in our source library used for this page, so this section describes the molecule and its function rather than how it is made.

What does UV-329 stand for, and what does octrizole mean?#

UV-329 is a generic industry code rather than a chemical name, and octrizole is the common name of the same substance, derived from the eight-carbon tert-octyl group on its phenol ring. In this family the generic code outranks the trade name as a search term, which is why suppliers across Asia and Europe list their grades under "UV-329" before they list "Tinuvin 329" or "UV-5411".

Is UV-329 the same as Tinuvin 329 and Cyasorb UV-5411?#

Yes: Tinuvin 329, Cyasorb UV-5411, SONGSORB 3290, Eversorb 72 and BLS 5411 are five supplier names for one substance, CAS 3147-75-9. Cyasorb UV-5411 is the name Syensqo uses after its spin-off from Solvay, which was listed on 11 December 2023 and which owns the Cyasorb line of UV absorbers; the underlying molecule, the CAS number and the dosage guidance are identical across every trade name.

Which UV-329 trade names share CAS 3147-75-9?#

Nine trade names in our source library map to CAS 3147-75-9, and the list below gives each one with its supplier where the supplier is recorded.

• Tinuvin 329 (BASF)
• Tinuvin 329 FL (BASF)
• Cyasorb UV-5411 (Syensqo)
• SONGSORB 3290 (Songwon)
• Eversorb 72 (Everlight Chemical)
• BLS 5411 (Mayzo)
• Sumisorb 340
• Kemisorb 79
• Uvinul 3029
• Milestab 329

Sumisorb 340, Kemisorb 79, Uvinul 3029 and Milestab 329 have no supplier recorded in our source library at this time, so they are listed by name only.

How Does UV-329 Protect Plastics from UV Light?#

UV-329 absorbs ultraviolet radiation between 300 and 400 nm and converts it to heat, so the photons never reach the chromophores and impurities that start photo-oxidation in the polymer. Sunlight at the Earth's surface begins at about 280 to 290 nm, and the UV absorbers intercept the part of that spectrum that a given polymer is most sensitive to. Because protection follows the Beer-Lambert relationship, concentration multiplied by path length, a thicker section or a higher loading absorbs proportionally more of the incoming light.

Where does the absorbed energy go? UV-329 dissipates it by excited-state intramolecular proton transfer (ESIPT): the phenolic proton moves across the intramolecular O-H...N hydrogen bond to the triazole nitrogen, the excited molecule relaxes to the ground state as heat, and the proton returns, leaving the molecule unchanged and available to absorb again. This reversible cycle is the reaction that interrupts the photodegradation of plastics chain before it starts, rather than after chain scission has already begun.

What is ESIPT, and why does it make UV-329 photostable?#

Excited-state intramolecular proton transfer (ESIPT) is the energy route that returns an excited UV-329 molecule to its ground state without breaking a bond: the phenolic proton moves across the intramolecular O-H...N hydrogen bond to the triazole nitrogen, the molecule relaxes as heat, and the proton returns. Crawford, in Progress in Polymer Science 24 (1999) 7-43, describes this as the mechanism that gives hydroxyphenyl benzotriazoles their photopermanence: because the cycle involves no net consumption of the molecule, a single UV-329 molecule can absorb and dissipate many photons over the service life of a part rather than being used up after one absorption event.

The ESIPT cycle runs in four steps, listed below.

1. Absorb a photon in the 300 to 400 nm range.
2. Transfer the phenolic proton across the intramolecular O-H...N hydrogen bond.
3. Release the excitation energy as heat during radiationless relaxation.
4. Return the proton to its ground-state position, restoring the original molecule.

No quantum yield, photostability half-life or service-life figure for UV-329 is recorded in our source library, so none is stated here.

Why does UV-329 need a HALS partner in thin sections?#

A UV absorber cannot protect the outermost surface layer of a part, because the Beer-Lambert relationship means protection builds up with concentration multiplied by path length, and at the surface the path length is zero. Hindered amine light stabilizers (HALS) close that gap: their radical-scavenging effect does not depend on thickness, because they intercept the radicals that photo-oxidation generates rather than the photons that trigger it, and they are regenerated rather than consumed in the process.

What Are the Physical and Chemical Properties of UV-329?#

UV-329 is a powder with a melting point of 102 to 106 °C (215.6 to 222.8 °F), a density of 1.18 g/ml and a molecular weight of 323.4 g/mol. Its absorption maxima sit at 301 and 343 nm with an extinction coefficient of 15,910 l/mol·cm, and thermogravimetric analysis shows a 1 % weight loss at 180 °C (356 °F).

Mayzo specifies 102 to 106 °C (215.6 to 222.8 °F) for BLS 5411 and Songwon specifies 103 to 105 °C (217.4 to 221 °F) for SONGSORB 3290: compare a certificate of analysis against the grade it belongs to, not against a single generic value. No solubility, particle size, bulk density or flash point for UV-329 is recorded in our source library, so those rows are omitted rather than estimated.

At what temperature does UV-329 start to volatilise?#

UV-329 loses 1 % of its weight at 180 °C (356 °F) in thermogravimetric analysis, which places it in the volatile half of the benzotriazole range that runs from 153 °C for UV-P to 333 °C for UV-360. At the 270 to 300 °C melt temperatures used to process PET and PBT, formulators generally move to a lower-volatility absorber such as Tinuvin 234, Tinuvin 1577 or UV-360 rather than pushing UV-329 through that heat history. How much of an additive survives compounding at all is covered under additive volatility, extraction and fogging.

Which Polymers Use UV-329, and at What Dosage?#

UV-329 is dosed at 0.1 to 0.5 wt% in most plastics, at up to 1.0 wt% according to the BASF Tinuvin 329 data sheet, and at 0.5 to 3 % in unsaturated polyester gel coats. Why does the same absorber need up to six times the loading in a gel coat? Because Beer-Lambert protection depends on concentration multiplied by thickness, and a gel coat is a thin, fully exposed surface layer that needs a higher local concentration to reach the same protection a thicker moulded section gets at a lower loading.

wt% is the dosage convention used for UV-329 across every polymer in our source library; it is not converted to phr here, because phr is the PVC and rubber convention and no phr figure for UV-329 is recorded.

UV-329 in polycarbonate#

Polycarbonate yellows through a photo-Fries rearrangement, and UV-329 is dosed at 0.1 to 0.5 wt% to intercept the 300 to 400 nm radiation that drives it. For thicker, more heavily exposed polycarbonate parts, formulators typically move to a co-extruded cap layer at a much higher local loading, using an absorber selected for higher-temperature stability, and our source library names Tinuvin 360, Tinuvin 1577, Tinuvin 1600, Tinuvin 234 and Uvinul 3030 for that role rather than UV-329 itself. Cap-layer loadings and the full grade list are on UV stabilizers for polycarbonate.

UV-329 in PET and other polyesters#

UV-329 is used in polyesters at 0.1 to 0.5 wt%, but its 180 °C (356 °F) 1 % weight-loss point sits well below the 270 to 300 °C melt temperatures of PET, PBT and PEN, so it suits the lower-temperature polyesters and coatings rather than bottle-grade PET. Where bottle-grade PET, PBT and PEN are processed at those higher melt temperatures, our source library records that formulators choose Tinuvin 1577, Tinuvin 1600, Tinuvin 234, Uvinul 3030 or Cyasorb UV-3638 instead, because those absorbers can survive the extra 90 to 120 °C of processing heat. Absorbers that survive a 280 °C melt are compared on UV stabilizers for PET.

UV-329 in rigid and flexible PVC#

UV-329 is one of three benzotriazoles our source library names for clear and flexible PVC, alongside UV-P and Tinuvin 571, because conventional HALS are largely ineffective in PVC. Pure PVC absorbs nothing above 220 nm, so degradation initiates instead at processing defects, hydroperoxides and carbonyl groups, and once eight or more conjugated double bonds form in a polyene sequence the material develops visible colour. Conventional N-H and N-CH3 HALS are deactivated in this environment because the hydrogen chloride released during dehydrochlorination protonates them, which is why the PVC package for clear and flexible grades relies on absorbers such as UV-329 rather than on HALS alone. Why HALS fail in PVC and what replaces them is explained on UV stabilizers for PVC.

UV-329 in styrenics (ABS, PS), acrylics and PVB#

UV-329 is dosed at 0.1 to 0.5 wt% in styrenics, acrylics and polyvinyl butyral, where it is normally paired with a low-molecular-weight HALS such as Tinuvin 770 or Uvinul 4050. ABS, PS, SAN and ASA yellow through butadiene oxidation and polyene formation, and the absorber-plus-HALS pairing addresses both the light and the radicals that the reaction produces. PMMA and other acrylics are inherently UV stable on their own, so in that case UV-329 protects the substrate behind the acrylic layer or the contents of a transparent part rather than the acrylic itself. The whole styrenic additive package sits in additives for ABS, SAN and ASA.

UV-329 in unsaturated polyester gel coats#

Unsaturated polyester gel coats take UV-329 at 0.5 to 3 %, six times the loading used inside a moulded part, because the gel coat is a thin and fully exposed surface layer. That higher loading follows directly from the Beer-Lambert relationship described above: a thin layer needs more absorber per unit volume to achieve the same protection a thicker section reaches at a lower percentage. No cure time, viscosity or weathering figure for UV-329 in gel coats is recorded in our source library, so the dosage range is described here without a performance claim attached to it.

What Is UV-329 Used For? 5 Application Areas in Plastics#

UV-329 is used in 5 application areas: glazing and sheet, signs and marine and automotive parts, gel coats, transparent PC, PET, PVC and styrenic compounds, and coatings. Coatings sit outside the scope of a plastics-focused reference and are named here only to bound the query, not developed further.

• Polycarbonate glazing and multiwall sheet
• Signs, marine parts and automotive components
• Unsaturated polyester gel coats
• Transparent PC, PET, PVC and styrenic compounds
• Coatings (outside the scope of this plastics-focused page)

Polycarbonate glazing and multiwall sheet#

Polycarbonate glazing and multiwall sheet are the largest single use of UV-329 in our source library, because sheet is both thick enough for a UV absorber to work and exposed for decades. Sheet formulations typically combine the absorber with a phosphite for melt stability and a mould release for demoulding, and the full package is set out in additives for polycarbonate and PC/ABS.

Signs, marine parts and automotive components#

Signs, marine parts and automotive components use UV-329 because all three combine a pigmented or transparent surface with permanent outdoor exposure. Marine laminates share the gel-coat use case described above, where a thin, highly exposed layer justifies the higher loading. No automotive OEM specification and no service-life claim for UV-329 is recorded in our source library, so this page does not quote SAE J2527 results for it. Exterior automotive parts carry their own stabilizer package, listed under additives for automotive plastics.

Transparent packaging and UV-barrier film#

UV-329 protects the contents of a transparent pack rather than the pack itself, which is the classic UV-barrier role of an absorber. Because it is not listed in Annex I of Regulation (EU) No 10/2011, UV-329 cannot be used in EU plastic food-contact materials, and in the United States 21 CFR 178.2010 clears it only for polycarbonate at up to 0.5 wt%, so a transparent food-contact film formulated outside the EU or outside polycarbonate needs a different absorber for regulatory reasons, independent of its optical performance.

How Does UV-329 Perform in Weathering Compared with Other Benzotriazoles?#

UV-329 absorbs at 301 and 343 nm with an extinction coefficient of 15,910 l/mol·cm, which places it between UV-P (301 and 341 nm, 16,150) and the chlorinated, red-shifted UV-326 (312 and 353 nm, 15,600). The chlorine substitution on UV-326 shifts its absorption further into the visible range and lets it transmit less than 1 % of light up to 370 nm, a stronger cut-off than UV-329 achieves at the same wavelength.

Absorption data are BASF technical-data-sheet values measured at 10 mg/l in chloroform. TGA values are the temperature at 1 % weight loss, 20 °C/min in air. Empty cells mean the value is not in our source library, not that it is zero.

On the volatility axis, a 1 % weight loss of 180 °C puts UV-329 level with UV-326 and 3 °C below UV-328, while the higher-molecular-weight chemistries reach much further: Tinuvin 234 at 264 °C, Tinuvin 1577 at 300 °C and UV-360 at 333 °C. That gap explains why the higher-molecular-weight absorbers, not UV-329, are chosen for high-temperature polyester processing.

Comparisons of retained gloss and colour across the benzotriazole UV absorbers are normally generated with accelerated weathering standards rather than single-point data: ISO 4892-2 and ASTM G155-25 for xenon-arc exposure, ISO 4892-3, ASTM G154-23 and ASTM D4329-26 for fluorescent UV exposure, and ASTM E313-20 for yellowness index. ASTM D1925, an older yellowness-index method, was withdrawn in 1995 and does not belong in a current weathering citation. No weathering result, retained-property figure or service-life value for UV-329 itself is recorded in our source library, so this section names the test methods rather than quoting a result. Cycle parameters and the ISO to ASTM equivalences are on accelerated weathering tests (xenon arc, QUV).

How Does UV-329 Interact with HALS, Antioxidants and Pigments?#

UV-329 is combined rather than used alone in durable parts: formulators pair it with a HALS for surface protection, with a phenolic antioxidant for melt stability, and they check pigment interactions before fixing the package. The 3 interactions that decide a UV-329 package are listed below.

• HALS partner. A hindered amine light stabilizer adds thickness-independent radical scavenging that a UV absorber alone cannot provide at the surface. E. T. Denisov, in Polymer Degradation and Stability 34 (1991) 325-332, described the cyclical regeneration of the aminoxyl radical that lets a HALS keep working without being consumed, a mechanism later clarified by Hodgson and Coote in Macromolecules 43 (2010) 4573 and reviewed by Gijsman in Polymer Degradation and Stability 145 (2017) 2-10.
• PVC constraint. Hydrogen chloride released during PVC processing deactivates conventional HALS, so formulators use NOR HALS or an absorber-only package such as UV-329 with UV-P or Tinuvin 571 instead.
• Pigment interaction. Copper phthalocyanine pigments absorb strongly in the UV, and their excited state can act as a photoinitiator, so a pigmented formulation can need a different stabilizer balance than the unpigmented version of the same compound.

No synergism ratio, antagonism figure, blooming value or extraction value for UV-329 is recorded in our source library, so this page does not state a fixed "1:1 UVA to HALS" rule. Pigment and stabilizer conflicts more broadly are catalogued under additive interactions: synergy and antagonism.

What Is the Regulatory Status of UV-329?#

UV-329 is REACH-registered, has been on the REACH Candidate List as a substance of very high concern since 23 January 2024 on vPvB grounds, is not on the authorisation list, is not listed in Annex I of Regulation (EU) No 10/2011, and is cleared by the US FDA only for polycarbonate at up to 0.5 wt% (status 22 September 2026).

The same matrix format, applied to any other additive, is available through our additive regulatory status checker.

Is UV-329 an SVHC?#

Yes: UV-329 was added to the REACH Candidate List on 23 January 2024 as a very persistent and very bioaccumulative substance under Article 57(e) of Regulation (EC) No 1907/2006, together with UV-326 (bumetrizole). The six benzotriazole UV stabilizers with a Candidate List entry were not listed together: UV-320 and UV-328 were listed on 17 December 2014 on PBT and vPvB grounds, UV-327 and UV-350 on 17 December 2015 on vPvB grounds, and UV-326 and UV-329 on 23 January 2024, also on vPvB grounds only. Candidate List inclusion is a disclosure and notification obligation, not a ban: UV-329 can still be placed on the market and used in the EU.

Does UV-329 require REACH authorisation under Annex XIV?#

No: UV-329 is not on Annex XIV of REACH, so no authorisation is required to use it in the EU as of 22 September 2026. ECHA published a draft Annex XIV recommendation naming UV-329 and UV-326 on 2 February 2026, and the consultation on that draft closed on 2 May 2026 with no final recommendation issued since. By contrast, UV-328 already sits on Annex XIV as entry 51 under Commission Regulation (EU) 2020/171, with a latest application date of 27 May 2022 and a sunset date of 27 November 2023, which shows what an Annex XIV listing would actually change if UV-329 were added to it. Sunset dates for the four benzotriazoles already on the REACH Annex XIV authorisation list are listed there.

Is UV-329 allowed in food-contact plastics?#

No, not in the EU: UV-329 is absent from the Union list in Annex I of Regulation (EU) No 10/2011, so it is not authorised for EU plastic food-contact materials. UV-326, the substance listed as an SVHC on the same day as UV-329, does carry an EU food-contact entry (FCM 470) inside group restriction 12 at SML(T) 30 mg/kg, a contrast that a compounder switching between the two substances needs to know before assuming they are interchangeable for a food-contact application. Group restriction 12 and the Union list are explained on EU 10/2011 plastic food contact materials regulation.

What is the FDA limit for UV-329 in polycarbonate?#

The US FDA allows UV-329 at up to 0.5 wt% in polycarbonate under 21 CFR 178.2010, and only under conditions of use E, F and G of 21 CFR 177.1580. This is a clearance under a specific regulation for a specific polymer and specific conditions of use, not a blanket approval, and this page describes it as "cleared under 21 CFR 178.2010" rather than "FDA approved." Conditions of use A to H are defined in the FDA food contact rules for plastic additives (21 CFR).

What does the 0.1 % SVHC threshold oblige for articles containing UV-329?#

A UV-329 loading of 0.1 wt% is exactly the threshold at which REACH duties start, and the normal dosage range of 0.1 to 0.5 wt% means most parts stabilised with UV-329 are above it. Candidate List inclusion triggers 4 duties, listed below.

• Article 33 communication. Suppliers must communicate the presence of UV-329 above 0.1 % w/w in an article to recipients down the supply chain, and answer a consumer request for that information within 45 days.
• Article 7(2) notification. Producers and importers must notify ECHA when UV-329 is present above 0.1 % w/w and the actor places more than 1 tonne per year on the market, within 6 months of the substance's Candidate List inclusion.
• SCIP database notification. Since 5 January 2021, Article 9(1)(i) of the Waste Framework Directive requires notification of articles containing a Candidate List substance above 0.1 % to the SCIP database.
• Safety data sheet on request. Under Article 31(3), a safety data sheet must be supplied on request for a non-classified mixture containing 0.1 % or more of UV-329.

The 0.1 % threshold is judged on each component article of a complex product, not on the finished assembly as a whole, following the Court of Justice ruling in case C-106/14 of 10 September 2015. Every duty and date for the whole class is tabulated under SVHC, Annex XIV and POPs status of benzotriazole UV absorbers.

Is UV-329 Safe? Health, Safety and Environmental Profile#

UV-329 has no EU harmonised hazard classification under the CLP Regulation (EC) No 1272/2008, and the minority notified classifications recorded in ECHA's database are H315 (skin irritation), H319 (serious eye irritation), H335 (respiratory irritation) and H412 (harmful to aquatic life with long-lasting effects). These are classifications reported by a minority of notifiers to ECHA's database, not an EU-wide harmonised entry.

The distinction that matters for the "uv 329 toxicity" question is this: the Candidate List entry rests on very high persistence and very high bioaccumulation under Article 57(e), which is an environmental-fate property, concluded by ECHA's PBT assessment on 1 February 2024, and not a toxicity classification. UV-329 is not classified as carcinogenic, mutagenic or toxic for reproduction. Our source library does not hold an LD50, a NOAEL, a log Kow or a bioaccumulation factor for UV-329, so none is stated here; the log Kow of 7.93 and log BAF of 2.6 to 3.4 that appear in some sources belong to UV-328, not UV-329, and are not transferred to this page. A vPvB conclusion is an environmental-fate finding, which is why UV-329 appears on lists of toxic plastic additives without carrying a toxicity classification of its own. Persistence and bioaccumulation are the properties tracked on plastic additives in the marine environment.

What Are the Alternatives to UV-329?#

The 4 alternatives our source library records for UV-329 are Tinuvin 234, Tinuvin 360, Tinuvin 1577 and Cyasorb UV-3638, and all 4 avoid the Candidate List entry that UV-329 and UV-326 carry.

UV-329 vs UV-326 (bumetrizole)#

UV-326 is the chlorinated, red-shifted counterpart of UV-329: it absorbs at 312 and 353 nm instead of 301 and 343 nm, and it transmits less than 1 % of the light up to 370 nm. The regulatory twist is that both were listed as SVHC on 23 January 2024 and both appear in the same draft Annex XIV recommendation of 2 February 2026, so switching from Tinuvin 326 (UV-326, bumetrizole) to UV-329, or the reverse, solves nothing on the compliance side.

UV-329 vs UV-328#

UV-328 is the benzotriazole that went all the way: it was listed as an SVHC on 17 December 2014, added to Annex XIV as entry 51 with a sunset date of 27 November 2023, and listed under the Stockholm Convention in May 2023 as the first non-halogenated plastic additive to become a persistent organic pollutant. What this means for UV-329 users: UV-328 (Tinuvin 328) shows the full escalation path from Candidate List to authorisation list to global POP, and UV-329 currently sits two steps behind it, with a Candidate List entry but no Annex XIV listing and no Stockholm Convention listing.

UV-329 vs Tinuvin 234 (UV-234)#

Tinuvin 234 is the low-volatility replacement for UV-329 in high-temperature processing: its 1 % weight-loss point is 264 °C against 180 °C, and the FDA clears it for polycarbonate at up to 3.0 wt% against 0.5 wt% for UV-329. Tinuvin 234 is not an SVHC as of 22 September 2026, but it is under ECHA PBT assessment following the PBT Expert Group's written procedure of 5 September 2025, so this page writes its status as "under assessment," never as "SVHC," until that process concludes.

UV-329 vs Tinuvin 360 (UV-360)#

Tinuvin 360 is the dimer of the UV-329 chemistry: two benzotriazole-substituted tert-octylphenol units joined by a methylene bridge, which raises the molecular weight from 323.4 to 658.9 g/mol and the 1 % weight-loss point from 180 to 333 °C. The trade-off is that Tinuvin 360 carries an EU harmonised classification as Aquatic Chronic 4 (H413), based on the RAC opinion of 5 December 2017, while UV-329 carries no EU harmonised classification at all.

UV-329 vs Tinuvin 1577 (hydroxyphenyl triazine)#

Tinuvin 1577 moves the chemistry from a benzotriazole to a hydroxyphenyl triazine, which shifts the absorption band to 280 to 350 nm and raises the 1 % weight-loss point to 300 °C. Formulators choose it because its very low tendency to chelate lets it work in polymers that contain catalyst residues, and unlike UV-329, Tinuvin 1577 has an EU food-contact entry (FCM 770, SML 0.05 mg/kg).

UV-329 vs Cyasorb UV-3638 (benzoxazinone)#

Cyasorb UV-3638 is the benzoxazinone option for PET: Mayzo states that it works at about one third of the benzotriazole dosage, and it is heat stable to 350 °C short term. That one-third dosage figure is a single-supplier claim rather than an independently verified ratio. Cyasorb UV-3638 also carries an EU food-contact entry (FCM 796, SML 0.05 mg/kg including its hydrolysis products), which UV-329 does not have.

Who Manufactures UV-329? Grades and Suppliers#

UV-329 is produced by 5 companies recorded in our source library, BASF, Syensqo, Songwon, Everlight Chemical and Mayzo, and it is registered under REACH in the reported 1,000 to 10,000 tonnes per year band. More producers, plant locations and certifications are in the directory of UV stabilizer and HALS manufacturers and suppliers.

Equivalent grades across suppliers are resolved with the plastic additive trade name lookup, whichever spelling a buyer searches, "stabilizer" or "stabiliser." Buyers should ask for the supplier's TDS and SDS, the melting range of the specific grade, and a written statement of the Candidate List status in the supply chain.

Request quotes for UV-329 from verified suppliers: grade, volume, polymer, country, delivery date. Send one request to several UV-329 suppliers, or request a UV-329 sample, with the plastic additive supplier finder.

How Do the Benzotriazole UV Absorbers Fit Together as a Regulated Class?#

UV-329 belongs to the hydroxyphenyl benzotriazoles, the largest class of UV absorbers for plastics and the one class in which 6 members now carry a substance-of-very-high-concern entry. Twelve members of the benzotriazole class of UV absorbers are covered on this site: UV-P, UV-326, UV-327, UV-328, UV-329, UV-320, UV-350, UV-234, UV-360, Tinuvin 571, Tinuvin 928 and Tinuvin 1130. The global UV stabilizer market was worth USD 2.53 billion in 2024 and is forecast to reach USD 3.72 billion by 2030, a CAGR of 6.76 % for 2025-2030, according to MarketsandMarkets (May 2025), and the benzotriazoles are the largest single chemistry inside that market.

The benzotriazole regulatory timeline: 2014, 2015, 2024 and 2026#

The benzotriazole UV absorbers have moved through the EU regulatory system in 4 waves, and the list below gives each dated step.

1. 17 December 2014: UV-320 and UV-328 are added to the Candidate List on PBT and vPvB grounds.
2. 17 December 2015: UV-327 and UV-350 are added to the Candidate List on vPvB grounds.
3. 6 February 2020: Commission Regulation (EU) 2020/171 adds UV-328, UV-327, UV-350 and UV-320 to Annex XIV as entries 51 to 54, with a latest application date of 27 May 2022 and a sunset date of 27 November 2023.
4. May 2023: the Stockholm Convention lists UV-328 in Annex A by decision SC-11/11.
5. 23 January 2024: UV-326 and UV-329 are added to the Candidate List on vPvB grounds, and ECHA's screening report of 18 January 2024 proposes a restriction on UV-320, UV-327 and UV-350 in articles.
6. 4 August 2025 and 2 February 2026: the EU POPs listing of UV-328 enters into force via Delegated Regulation (EU) 2025/843, and ECHA publishes its draft Annex XIV recommendation covering UV-326 and UV-329, with the consultation closing 2 May 2026.

Tinuvin 327 (UV-327) illustrates the paradox in this timeline: it still holds EU food-contact entry FCM 469 in group restriction 12, even though its EU use has required authorisation since the Annex XIV sunset date of 27 November 2023.

Octrizole outside plastics: cosmetics, cleaning products and candle wax#

The name octrizole also appears in cosmetic, cleaning-product and candle-wax listings, and none of those uses is covered by this page, which is limited to plastics. Search results for "octrizole" are dominated by cosmetic ingredient databases and cleaning-product guides, and search results for "UV 5411" include candle-making suppliers alongside the industrial grades described above. This page states no cosmetic regulatory status for octrizole, because that data set is separate from the plastics regulatory matrix covered here. A quoted "octrizole" product needs confirmation as UV-329 at CAS 3147-75-9 before it is ordered for a plastics application.

Is UV-329 banned?#

No: UV-329 is not banned or restricted anywhere covered by this page, and Candidate List inclusion is a disclosure and notification obligation rather than a prohibition (status 22 September 2026). Inclusion in the Candidate List creates duties to communicate and notify, not a prohibition on manufacture, import or use.

Is UV-329 a POP like UV-328?#

No: UV-329 is not listed under the Stockholm Convention or in Annex I of the EU POPs Regulation (EU) 2019/1021, whereas UV-328 has been in both since decision SC-11/11 of May 2023 and 4 August 2025 respectively. The listed plastic additives and their trace-contaminant limits are on POPs in plastics.

Does UV-329 have an SDS and a TDS?#

Yes: every supplier issues a safety data sheet and a technical data sheet for UV-329, and since 23 January 2024 the safety data sheet must state the Candidate List entry. Article 31(3) requires that safety data sheet on request for a mixture containing 0.1 % or more of a Candidate List substance, in line with the 21 CFR food contact rules documentation expectations that apply on the US food-contact side.

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