Presented at the SPE Thermoplastic Elastomers TOPCON, September 2018. This paper discusses how UV-328 and other benzotriazoles came to be classified as SVHC under REACH, and identifies potentially safer substitutes for additive users based on the results of a hazard assessment.

1. BotkinChemie
Substitution of Benzotriazole UV
Absorbers in Plastics
Jim Botkin
SPE Thermoplastic Elastomers TOPCON
September 20, 2018

2. BotkinChemie
Benzotriazole UV Absorbers
• Widely used as light stabilizers in plastics and coatings
• Function by competitive absorption of harmful UV light
• Products with wide range of secondary properties (e.g.
physical form, volatility, melting point) are available
• Substitution of some products is being driven by
regulatory pressures from Europe

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Questions
• What products are affected?
• What is happening and what does it mean?
• Why are some products being regulated?
• Will other products be regulated in the future?
• How can safer substitutes be identified?
• How to formulate in new applications to minimize risks?

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AFFECTED PRODUCTS, STATUS, & IMPLICATIONS

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Commercial Benzotriazole UV Absorbers
X R R’
UV-P H H CH3
UV-234 H tert-cumyl tert-cumyl
UV-320 H tert-butyl tert-butyl
UV-326 Cl tert-butyl CH3
UV-327 Cl tert-butyl tert-butyl
UV-328 H tert-pentyl tert-pentyl
UV-329 H H tert-octyl
UV-350 H sec-butyl tert-butyl
UV-360 H CH2-UV-329 tert-octyl
UV-928 H tert-cumyl tert-octyl

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Status in the EU: 2014-2015
• UV-328, UV-320, UV-327, & UV-350 on the Candidate
List of Substances of Very High Concern (SVHC)
– Evaluated as persistent, bioaccumulative, and toxic (PBT) and/or
very persistent and very bioaccumulative (vPvB)
– Increased regulatory burden is driving additive users to phase
out their use
• Informal evaluations of six other benzotriazoles initiated
under the PACT – RMOA program

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Status in the EU: 2018
• ECHA recommended addition of UV-328, UV-320,
UV-327, and UV-350 to the REACH Annex XIV List
(“Authorisation List”) in February 2018
– Increased pressure to phase-out due to additional regulatory
requirements
• PACT – RMOA evaluations of the six other
benzotriazoles are still pending

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Status of Benzotriazole UV Absorbers
X R R’
UV-P H H CH3
UV-234 H tert-cumyl tert-cumyl
UV-320 H tert-butyl tert-butyl
UV-326 Cl tert-butyl CH3
UV-327 Cl tert-butyl tert-butyl
UV-328 H tert-pentyl tert-pentyl
UV-329 H H tert-octyl
UV-350 H sec-butyl tert-butyl
UV-360 H CH2-UV-329 tert-octyl
UV-928 H tert-cumyl tert-octyl
On the Candidate List of SVHC,
recommended to the Authorisation List
Assessment under PACT – RMOA

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Status in Other Countries
• Japan Chemical Substance Control Law (CSCL)
– UV-320: Class I Specified Chemical Substance
– UV-327 & UV-350: Monitoring Chemical Substances
– No special restrictions on other benzotriazoles, including UV-328
• USA
– No current assessments by the EPA under TSCA
• Canada
– Screening assessment of UV-328 completed with no further action
• The importance of Europe in global supply chains continues to drive
additive users to replace UV-328 with safer alternatives

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RATIONALE FOR REGULATION:
PERSISTENCE, BIOACCUMULATION, & TOXICITY

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Definitions
• Persistence (P) is resistance to environmental
degradation through natural processes
• Bioaccumulation (B) is the tendency of a substance to
accumulate in organisms
• Toxicity (T) is the degree to which a substance can
damage an organism
• PBT (and vPvB) chemicals are of special concern to
regulators such as ECHA and the EPA

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Benzotriazoles and PBT
• PBT properties are assessed using standardized tests
• Regulators have set criteria to designate chemicals as
PBT or vPvB based on the test results
• Only UV-320, UV-327, UV-328, and UV-350 appear to
meet the REACH criteria for PBT or vPvB
• Criteria used by regulators to evaluate chemicals as PBT
and vPvB may be subject to change

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IDENTIFYING SAFER ALTERNATIVES:
HAZARD ASSESSMENTS

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Hazard Assessment
• Part of a larger alternatives assessment process
• Provides a framework to rank attractiveness of
alternatives based on analysis of hazard data
– Numerical ratings make comparisons easier
• Based on methods developed by or consistent with
those used by regulatory agencies
• Supports informed decision-making by additive suppliers,
formulators, and end users

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Examples of Hazard Assessment Methods
• GreenScreen® for Safer Chemicals
• Quick Chemical Assessment Tool (QCAT)
• GreenScreen List Translator™
• EPA TSCA Work Plan chemical scoring
GreenScreen® and GreenScreen List Translator™ are trademarks of Clean Production Action

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TSCA Work Plan Chemical Scoring
• Hazard (toxicity) Scores (1-3 scale) are assigned based on
data for 10 different toxicological endpoints
• Bioaccumulation (B) scores (1-3 scale) determined using
experimental Bioconcentration Factor (BCF) values
• Persistence (P) scores (1-3 scale) determined based on
degradation half life times
• B and P scores are normalized to give a PB score (1-3 scale)
• The PB and Hazard Scores can be summed to give a Total
Score (2-6 scale)

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Benzotriazole Hazard Assessment
• Scope: UV-328 and six alternatives were assessed
• The TSCA Work Plan chemical scoring criteria were applied to
data from the REACH dossiers to obtain Hazard and
Bioaccumulation (B) Scores
• All of the benzotriazoles were assumed to be highly persistent
and assigned Persistence (P) Scores of 3 (high)
• Normalized PB Scores were obtained by combining the P and
B Scores
• Substances were ranked based on the Total Score
(sum of Hazard Score and PB Score)

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Hazard Scoring
UV-328 1 - 1 2 1 - 3 - 1 - 3
UV-P 1 1 1 1 1 - 2 - 1 3 3
UV-234 1 - 1 - 1 - 2 - 1 1 2
UV-326 1 1 1 1 1 - 1 - 1 1 1
UV-329 1 - 1 1 1 - 2 - 1 1 2
UV-360 1 - 1 1 1 - 1 - 1 1 1
UV-928 1 - 1 - 1 - 1 - 1 1 1
Values in italics are deemed to be of low confidence

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Calculation of Total Score
Max.
BCF
B Score P Score
PB
Score
Hazard
Score
Total
Score
UV-328 5,580 3 3 3 3 6
UV-P 494 1 3 2 3 5
UV-234 1,286 2 3 3 2 5
UV-326 895 1 3 2 1 3
UV-329 461 1 3 2 2 4
UV-360 1.5 1 3 2 1 3
UV-928 (1,286) 2 3 3 1 4
Values in italics are deemed to be of low confidence

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Comparison of Bioaccumulation & Toxicity Hazards
UV-328
UV-P
UV-234
UV-329
UV-928
UV-326
UV-360
1,000
5,000
Bioaccumulation(BCF)
Hazard Score 1
(low toxicity)
Hazard Score 2
(medium toxicity)
Hazard Score 3
(high toxicity)
0

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CONCLUSIONS & RECOMMENDATIONS

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Conclusions
• None of the alternatives (UV-P, UV-234, UV-326,
UV-329, UV-360, UV-928) meet the REACH criteria for
identification as PBT or vPvB based on available data.
• Based on the hazard assessment, the most attractive
alternatives include UV-326, UV-329, UV-360, & UV-928.
• Less attractive alternatives include UV-P and UV-234.

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Recommendations
• Consider phase-out of UV-328 (and UV-320, UV-327, UV-350) in existing
applications and avoid use in new applications.
• Based on the results of the hazard assessment, UV-326, UV-329, UV-360,
and UV-928 represent preferred alternatives to UV-328.
• GreenScreen® assessments of UV-P and UV-234 would be helpful to better
understand their inherent hazards and suitability as alternatives to UV-328.
• Hazard assessments can be used to identify other substances of concern
(flame retardants, plasticizers, etc.) and safer alternatives.
• In today’s regulatory environment, assessing hazards is as important as
assessing performance, cost, and commercial availability.

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Thank you for your attention!
Jim Botkin
www.botkinchemie.com
(732) 309-3476
jim@botkinchemie.com
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This presentation © 2018 James H. Botkin dba BotkinChemie