UV absorber
[Overview]
Ultraviolet absorbers are currently the most widely used type of light stabilizers. According to their structures, they can be divided into salicylates, benzophenones, benzotriazoles, substituted acrylonitriles, and triazines. etc., the most widely used in industry are benzophenones and benzotriazoles. Quenchers are mainly metal complexes, such as divalent nickel complexes, etc., which are often used together with ultraviolet absorbers to have a synergistic effect. [1]
【Product Introduction】
This product is a highly efficient light stabilizer with a wide range of UV absorption properties and low volatility. It is suitable for polystyrene, polymethyl methacrylate, polyester, rigid polyvinyl chloride, polycarbonate, and ABS. Resin etc. It is particularly effective in transparent products and engineering plastics processed at high temperatures. Used together with antioxidants, it has a high-quality synergistic effect and can improve the weather resistance and thermal oxygen stability of the product.
Molecular weight: 323
Chemical Abstracts registration number: 3147-75-9
Appearance: white powder
Melting point: 103-105℃
Purity: ≥99% (GC)
Light transmittance: 440nm, ≥98% 500nm, ≥99%
Volatile content: ≤0.3%
Packing: 1kg, 5kg, 25kg, 50kg.
UV absorber
It has the ability to absorb ultraviolet rays and is used to prevent plastics, coatings and other substances from photodegradation caused by long-term exposure to sunlight.
Structural formula:
[Having the conditions]
UV absorbers should meet the following conditions:
① Can strongly absorb ultraviolet rays (especially the wavelength of 290-nm);
②Thermal stability is good, it will not change due to heat even during processing, and the thermal volatility is small;
③Good chemical stability and no adverse reactions with material components in the product;
④Good miscibility, can be evenly dispersed in the material, no blooming, no bleeding;
⑤The absorber itself has good photochemical stability and does not decompose or discolor;
⑥ Colorless, non-toxic, odorless;
⑦ Resistant to soaking and washing; ⑧ Cheap and easy to obtain.
[Function]
Ultraviolet absorber is a kind of light stabilizer that can absorb the ultraviolet part of sunlight and fluorescent light sources without changing itself.
Since sunlight contains a large amount of ultraviolet light that is harmful to colored objects, its wavelength is about 290-460 nanometers. These harmful ultraviolet light causes the color molecules to eventually decompose and fade through chemical oxidation-reduction (Redox reaction).
Methods to prevent harmful UV light from damaging color are both physical and chemical.
Here we only briefly introduce chemical methods, that is, using ultraviolet absorbers to effectively prevent or weaken the color damage of protected objects.
[Common Types]
1. Trade name salicyl phenyl ester
Ingredients Phenyl ortho-hydroxybenzoate
Performance and use Colorless crystalline powder. Has a pleasant aromatic smell (wintergreen oil smell). Density 1.250g/cm3, melting point 43, boiling point (1.6kPa) 173. Easily soluble in ether, benzene and chloroform, soluble in ethanol, almost insoluble in water and glycerin. Content 99%.
This product is a UV absorber, used in plastic products, but its absorption wavelength range is narrow. The U.S. Food and Drug Administration approves acrylic resin articles for use in contact with food.
Packaging, storage and transportation Paper drums lined with plastic bags. Store and transport according to general chemical regulations.
2. Trade name UV absorber UV-P
Ingredients: reaction product of o-nitroaniline and p-cresol
Performance and use Appearance is colorless or light yellow crystal. It can be dissolved in various organic solvents such as gasoline, benzene, acetone and so on. It has very little solubility in water and is not decomposed by concentrated alkali or concentrated acid. It can ionize with heavy metals to form salts. Can absorb ultraviolet rays with a wavelength of 270~280nm. Melting point is 130~131.
This product is mainly used in polyester, chlorine-containing polyester, fiber acetate, polyvinyl chloride, polystyrene, organic glass, polyacrylonitrile and other resins. The stability in transparent products is better than that in colored products. The dosage in products is 0.% ~ 0.5%.
3. Trade name UV absorber UV-O
Ingredients 2,4-dihydroxybenzophenone
Performance and use This product is light-colored needle-like crystals or white powder. Moisture <0.5%. Ash content <0.5%. Melting point 136~149℃. Soluble in acetone, methanol, ethanol, methyl ethyl ketone, dioxane, N-methylpyridone and ethyl acetate, extremely insoluble in water, n-heptane and benzene. The solubility of this product in some solvents (g/100ml solvent, 25°C) is acetone 50, benzene 1, ethanol ＞ 50, water ＜ 0.5, n-heptane ＜ 0.5.
This product is a UV absorber, suitable for polyvinyl chloride, polystyrene, epoxy resin, cellulose resin, unsaturated polyester, coatings and synthetic rubber. The maximum absorption wavelength range is 280~340nm, and the general dosage is 0.1% to 1%. However, the light stabilizing effect of this product is not outstanding.
Safety Precautions The oral LD50 of this product in white mice is 8.6g/kg body weight, and the oral LD50 in white mice is 2.336mg/kg body weight. No toxic effects were seen at the doses of 0.19, 0.60, and 1.90g/kg. The development of the experimental animals at the other two doses was affected, and the blood phase was changed.
4. Trade name UV absorber UV-9
Ingredients 2-hydroxy-4-methoxybenzophenone
Performance and use This product is light yellowOr white crystalline powder. Density 1.324g/cm3 (2℃5). Melting point 62~66℃. Boiling point: 150~160℃ (0.67kPa), 220℃ (2.4kPa). Soluble in most organic solvents such as acetone, ketone, benzene, methanol, ethyl acetate, methyl ethyl ketone and ethanol, but insoluble in water. The solubility of this product in some solvents (g/100g solvent, 25) is 56.2 in benzene, 4.3 in n-hexane, 5.8 in ethanol (95%), 34.5 in carbon tetrachloride, 51.2 in styrene, and 18.7 in DOP.
This product is a UV absorber, suitable for various plastics such as polyvinyl chloride, polyvinylidene chloride, polymethyl methacrylate, unsaturated polyester, ABS resin and cellulose resin. The maximum absorption wavelength range is 28. 340nm, general dosage is 0.1% ~ 1.5%, good thermal stability, decomposes at 200°C. This product hardly absorbs visible light, so it is suitable for light-colored transparent products. This product can also be used in paint and synthetic rubber.
Safety Precautions Japan and Italy stipulate that when this product is used in products that come into contact with food, the maximum dosage should not exceed 0.3%.
5. Trade name UV absorber UV-531
Ingredients 2-hydroxy-4-n-octyloxybenzophenone
Matting Powder
Formosa Plastics Group Performance and Use This product is a light yellow or white crystalline powder. Density 1.160g/cm3 (25℃). Melting point 48~49℃. Soluble in acetone, benzene, ethanol, isopropyl alcohol, slightly soluble in dichloroethane, insoluble in water. The solubility of this product in some solvents (g/100 solvent, 258), in the solvent acetone is 74, benzene 72, methanol 2, ethanol (95%) 2.6, n-heptane 40, n-hexane 40.1, water 0.5.
This product is an ultraviolet absorber that can strongly absorb ultraviolet light with a wavelength of 270-330nm. It can be used in various plastics, especially polyethylene, polypropylene, polystyrene, ABS resin, polycarbonate, polyvinyl chloride and resin. It has good compatibility and low volatility. The general dosage is 0.1% to 1%. It has a good synergistic effect when used together with a small amount of 4,4-thiobis(6-tert-butyl-p-cresol). This product can also be used as a light stabilizer for various coatings.
Safety Precautions: This product has low toxicity. Many countries have approved this product for use in plasticized products that come into contact with food, such as the United States for polyolefins, the United Kingdom (maximum dosage 0.6%), and Italy (maximum dosage for polyethylene and polypropylene). The dosage in Japan is: polyethylene 0.5%, polypropylene 1%, AS resin and ABS resin 0.5%, polyvinyl chloride 0.2% (do not contact greasy foods or foods with ethanol content exceeding 20%) .
1. Li Heping． Fine Chemical Technology: Science Press, 2005
