Low volatility
High MW keeps it in the polymer at high processing temperatures.
SUNSORB® 234
UV-234 Benzotriazole UV Absorber Supplier
SUNSORB® 234 (UV-234) is a high-molecular-weight benzotriazole UV absorber with very low volatility. It is designed for polymers processed at high temperatures, such as PC, PET, PA and their blends.
CAS 70321-86-7 · Benzotriazole · UV absorber
- Lot COA with every shipment
- Samples for your trials
- Technical support for your trial
Product overview & key benefits
UV-234 (2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol) has a molecular weight of 447.6 and stays in the polymer during high-temperature processing. It is used in polycarbonate, polyesters, polyamides, PC/ABS and automotive coatings.
Engineering plastics
Designed for PC, PET, PA and their blends.
Durable protection
Good long-term retention in thin and thick parts.
Technical specifications
| Parameter | Typical value |
|---|---|
| Product Name | UV Absorber UV-234 |
| Brand | SUNSORB® 234 |
| CAS No. | 70321-86-7 |
| Chemical Name | 2-(2H-Benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol |
| Molecular Formula | C30H29N3O |
| Molecular Weight | 447.6 |
| Appearance | Light-yellow powder |
| Melting Point | 137–141 °C |
| Assay | ≥99% |
| Volatile Matter | ≤0.5% |
| Ash | ≤0.1% |
Typical specification. Every shipment is supplied with a batch COA; the limits that apply to your order are confirmed in the quotation and contract.
Applications by Material
Pick an application to see how 234 is normally used and what to confirm before your trial.
Polycarbonate & PC Blends
UV protection for PC sheet, glazing and PC/ABS parts.
Check before trial
- Part thickness
- Processing temperature
- Clarity requirement
PET, PBT & Polyester
UV absorber for polyester film, fiber and molded parts.
Check before trial
- Process and temperature
- Thickness
- Color requirement
Polyamide & Automotive Coatings
Used in polyamide parts and automotive coatings.
Check before trial
- System type
- Exposure
- HALS used
Selection & comparison
Selecting a UV Absorber
| Your requirement | What usually works |
|---|---|
| Clear or light-colored polyolefin parts and film | Benzophenone (531) or benzotriazole (326) at low loading |
| High processing temperature (PC, PET, PA) | Low-volatility grades: 234, 360 or 1577-type triazines |
| Thin films and fibers | Higher-MW, low-volatility grades so the absorber is not lost in processing |
| Solvent-borne and waterborne coatings | Liquid benzotriazoles (384-2, 1130) or triazine (400), paired with a HALS |
| Outdoor service longer than one season | UV absorber plus a HALS; the absorber filters, the HALS stops radical chains |
| Exports to the EU | Check REACH status first; some benzotriazoles (327, 328) are restricted |
| Replacing an existing grade | Send your current TDS or COA; we match on chemistry and the parameters you approve |
UV Absorber Comparison
Swipe or scroll horizontally to see all columns →
| Product | Chemistry | Mol. weight | Melting point / form | Best fit | Typical starting level* |
|---|---|---|---|---|---|
| SUNSORB® 234 | Benzotriazole | 447.6 | 137–141 °C | PC, PET, PA at high temperature | 0.1–0.5% |
| SUNSORB® 329 | Benzotriazole | 323.4 | 103–105 °C | PC, PET, PVC, PMMA | 0.1–0.5% |
| SUNSORB® 360 | Bis-benzotriazole | 658.9 | ≥195 °C | PC, PET, PBT, thin parts | 0.1–0.5% |
| SUNSORB® 326 | Benzotriazole (Cl) | 315.8 | 138–141 °C | PP, PE, PVC, adhesives | 0.1–0.5% |
| SUNLIGHT® 770 | Monomeric HALS | 480.7 | White powder or granule | Thick PP, PE, styrenics | 0.1–0.5% |
*Starting points for trials, not fixed recommendations. Loading depends on part thickness, pigment, target service life and the HALS used alongside. UV absorbers and HALS work by different mechanisms and are usually combined.
Packaging & storage
Packaging
25 kg net bags or cartons with a PE inner liner. Palletized; private-label packing on request.
Storage
Keep sealed in a cool, dry, ventilated place away from heat and direct sun. See the SDS for full handling details.
Lead time & terms
Typically 3–15 business days from order confirmation, depending on quantity. FOB, CIF or DAP to major ports.
From first email to approved supply
Define the exposure
Indoor light behind glass, outdoor temperate climate and desert or tropical exposure need very different packages. Note the target service life and the weathering test you use (xenon or QUV, hours, ΔE or gloss retention).
Match absorber to process and thickness
A UV absorber works by filtering, so it needs enough path length: thick parts need less, thin films and fibers need more and need a low-volatility grade. Check the absorber survives your processing temperature.
Combine with a HALS
For outdoor use the standard approach is UV absorber plus HALS. Send your current package and pigment system and we suggest a starting combination for the trial.
Check regulations before you buy
Some benzotriazoles are restricted in the EU and other markets. Tell us the destination and end use, and we confirm the REACH and food-contact position of the grade before you order.
Tell us your requirement. We match the grade.
Start with your material, part thickness, quantity and destination. Add your current UV package and we will quote against it.
| Information | Example |
|---|---|
| Polymer / Material | PP, PE, ABS, compound, masterbatch |
| Application | Injection molding, extrusion, film, fiber |
| Current additive | Grade or supplier you use today |
| Required specification | Your TDS, COA or key limits |
| Quantity | Trial order / monthly / annual volume |
| Packaging | Standard 25 kg or specific requirement |
| Destination | Country and port |
| Documents needed | COA, SDS, REACH, food-contact statement |
Related products
UV Absorber UV-234 FAQ
When is 234 better than 329?
When processing temperature is high or sections are thin, 234's lower volatility gives better retention.
What dosage is typical?
0.1–0.5% in plastics; confirm with your weathering test.
Can 234 replace 327 or 328?
In many engineering-plastic applications, yes. A weathering re-test is needed.
Can I get a sample before ordering?
Yes. Tell us the polymer, the test you plan to run and the quantity you need. Samples ship with a COA so you can compare the lot against your current material.
What if a COA does not match our agreed specification?
Send us the agreed specification and the COA showing the difference (parameter, unit and test method). We check it with the production batch record before you accept the material, and replace or re-test where the lot is out of specification.
