LOTSORB UV328 (CAS: 25973 – 55 – 1)

Product Description

Lotsorb UV 328 is a UV absorber of the hydroxyphenyl-benzotriazole class designed for  coatings. Because of its extended UV absorption,Lotsorb UV 328 provides efficient protection  to coatings and light sensitive substrates. 

Key Features & Benefits 

- Hydroxyphenyl-benzotriazole UVA with excellent spectral coverage in the UV A & B regions

- Good photopermanence 

- Improves exterior durability of ambient and low temperature cured coatings

CAS number                

25973 – 55 – 1

Molecular weight   

351.5

Chemical Structure

 2-(2H-benzotriazol-2-yl)-4, 6-ditertpentylphenol

Properties  Typical

Properties 

Appearance                           slightly yellow powder 

Solubility (g/100 g solution) at 20 °C:

butylcarbitol                           3.5

butanol                                   2.5 

butyl acetate                           15 

ethylglycol                               4

1-methoxypropylacetate-2     10 

methylethylketone                  14 

Solvesso 100¹                          25 

Solvesso 150¹                          25 

xylene                                      34 

water                                      < 0.01 ¹

Transmittance Spectrum (in toluene, cell thickness 1 cm)

Top Line: 0.001% Lotsorb UV 328, corresponds to 0.25% in a 40 µ film 

Second Line: 0.002% Lotsorb UV 328, corresponds to 0.50% in a 40 µ film 

Third Line: 0.004% Lotsorb UV 328, corresponds to 1.0% in a 40 µ film 

Bottom Line: 0.006% Lotsorb UV 328, corresponds to 1.5% in a 40 µ film

Applications 

Lotsorb UV 328 is recommended for applications such as: 

• Automotive coatings

• Industrial coatings 

• Trade sale paints such as wood stains or do-it-yourself paints 

• Adhesives

 Lotsorb UV 328 may be used in combination with a light stabilizer of the sterically hindered amine or  aminoether class (HALS) such as Lotsorb UV 292, Lotsorb UV 123, or Lotsorb UV 249. These combinations  give coatings superior protection against gloss reduction, cracking, blistering, delamination and  color change. Lotsorb UV 328 is only recommended for ambient and low temperature cured systems,  i.e. air-drying alkyd-based systems. The amount of Lotsorb UV 328 required for optimum performance should be determined in laboratory  trials covering a concentration range.

Recommend Concentrations 

Lotsorb  328                                                                                 1.0 – 3.0 % 

+ 

Lotsorb UV 249,  Lotsorb UV 292 or  Lotsorb UV 123                  0.5 – 2.0 % 

(concentrations are based on weight percent binder solids)

Packaging and handling 

Packaging: 20Kg/Carton       

Store the product in a cool, dry, well-ventilated area away from incompatible materials. Unless stated, proper storage will permit usage of the product for 12 months from the manufacture date. For additional handling and toxicological information, consult the Material Safety Data Sheet.