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Light stabilizers definition
Light stabilizer, light stability the agent, photo stabilizer, solar radiation of electromagnetic waves through space and the ozone layer, the rays below 290nm and 3000nm above almost all are filtered out, actually reach the ground for the electromagnetic waves of 290nm-3000nm wavelength range 400 -800nm ​​(about 40%) of visible light, the wavelength is about 800-3000nm (about 55%) of the infrared wavelength of about 290-400nm (only 5%) of ultraviolet light.
Edit this paragraph, the mechanism of light stabilizers
The mechanism of action of the light stabilizer due to its own structure and the different varieties vary. Some can shield the reflection UV or absorb ultraviolet light and turn it into harmless heat energy; some quenching can be UV-excited molecules or groups of excited states, to return to the ground state, eliminate or mitigate the occurrence of photo-oxidation the possibility of the reduction reaction; capture to restore the free radicals produced by photo-oxidation, thereby preventing free radical reactions leading to products of aging, so that products from UV damage. Light aging in the industry to effectively prevent retard, more than two or more different mechanism of action anti-aging agent compound, a variety of anti-aging agent, especially light absorbent has its own different UV absorption band. Compound formulations: two stupid ketone + benzotriazole and hindered amine (HAL), can play a single light stabilizers can not be achieved the best results. Added UV absorbers in sunscreen cosmetics, sun protection mechanism is based on the dispersion or absorption of incident UV on the skin surface, so that the skin to avoid or reduce UV damage.
Edit this paragraph, light stabilizers.
, According to the mechanism of action can be divided into 1) light shielding agent, 2) UV absorbers (UV Absorber), 3) quencher (quencher), 4) free radical scavenger. 1) light shielding agent: it acts as a barrier between the polymer and optical radiation, so that light can not direct radiation internal to the polymer, the polymer internal from the hazards of ultraviolet radiation, which effectively inhibit the photo-oxidation degradation. 2) UV absorbers: its mechanism of action is strongly absorbed polymer sensitive to ultraviolet light, and can change the energy as a harmless form of the heat release. 3) quenchers: You can accept the energy absorbed by the chromophores in the plastics, and energy in the form of heat, fluorescent or phosphorescent divergence out, bring it back to the base material, thereby protecting the polymer from UV damage. Second, the chemical structure can be divided into 1) salicylic acid lipids, 2) benzophenone (benzophenone), 3) benzotriazole (benzotriazol), 4) triazine, 5) to replace the acrylonitrile class 6) grass lactam, 7) organic nickel compounds class, 8) Hindered amine (HAL), etc..
Edit this paragraph, light stabilizers to choose
Light stabilizers should consider the following factors: 1, the effective absorption of 290-400nm wavelengths of ultraviolet light, or quenching of excitation energy of the state molecule, or the ability to capture free radicals; own light stability and thermal stability good; 3 compatibility, not oozing during use; 4, hydrolysis resistance, water resistance and solvent extraction; 5, low volatility, polluting;, non-toxic or low toxic, inexpensive and easy to too. Light stabilizers can be divided into four categories: (1) light shielding agent, carbon black, zinc oxide, titanium dioxide and zinc, barium; (2) UV absorbers: the most widely used in industry benzophenone, salicylic acid and benzo-triazole; (3) quenchers: metal complexes, organic complexes such as nickel, cobalt, and iron; (4) free radical scavenger: Hindered Amine derivatives. Among them, the light shielding agent can reflect or absorb sunlight, ultraviolet rays, that is, set a barrier between the polymer and the light source to prevent ultraviolet light within the depth of polymer, the polymer can be protected. UV absorbers is selectively strong absorption of harmful sunlight UV on the polymer itself has a high degree of lightfastness of organic compounds. Quencher is an effective transfer of polymer in the photosensitive chromophore excited state energy and dissipated so that the polymer light stabilizers from photo-degradation reaction to a harmless form. Free radical scavenger is to cut through the capture and free radical scavenging auto-oxidation chain reaction to achieve.
Edit this paragraph, the preparation of the light stabilizer
Benzophenone-type information recording materials, light stabilizers: the light stabilizers can inhibit dye laser material, information recording materials uv fade, so as to improve by adding this light stabilizers, dyes, laser materials, information recording materials weatherability, anti-photo-oxidation ability to fade. The composition of the light stabilizer is through the introduction of benzophenone functional group with UV absorption and UV quenching sulfonate nickel compounds form a series of derivatives, and benzophenone molecule functional groups and from the anti-photo-oxidation The stabilizing effect of phenol and its derivative compounds formed a series of compounds and mixtures thereof. Weathering test results show that the light stabilizer for dyes, laser materials, information recording materials and anti-UV oxidation fading significant results. P3395-light stabilizer polyester preparation methods: the corresponding hydroxypiperidine straight-chain alcohols and straight-chain dicarboxylic acid ester monomer raw materials in the presence of the catalyst organic titanate polycondensation reaction. Polycondensation reaction of often compression polyethylene and vacuum condensation two, often compressed poly 1 to 5 hours, decompression polycondensation time is 3 ~ 7 hours, the vacuum was .094 ~ 0.1MPa, the reaction temperature are 140 ~ 200 ℃. Polycondensation reaction system by adding antioxidant sub-Tris (2,4 - di-tert-butyl-phenyl) ester, the amount of 0.1 to 2.0wt% of the total reactants, and the structure of formula I: where R is ethylene or Propane, R1, C3 C5 straight chain carbon chain, R2 is methyl or ethyl, n is a positive integer of 20 to 50. Dyes and its information recording materials light stabilizer: a dye laser material, information recording materials to prevent the UV oxidation fade technical fields. The background technology from the IT and laser technology. By adding this light stabilizers to achieve the dyes, laser materials, information recording materials weathering, resistance to photo-oxidation of the ability to fade. The composition of the light stabilizer by the chemical formula: NN * hydroxyphenyl, 2 - (N'-N * '-hydroxyphenyl) benzotriazole and 1-R, NN * R * Benzotriazole Benzotriazole Benzotriazole triazole and its derivatives. Examples include 2 - (2 ', 4'-dihydroxyphenyl) -5,6 - dihydroxyphenyl triazole and 1,6 - dihydroxybenzoate and triazole. Weathering test results show that the light stabilizers, dyes, laser materials, information recording materials and anti-UV oxidation decoloration significant results. Light stabilizers intermediate 2,2,6,6 - tetramethyl - 4 - Preparation of piperidine amines: more precisely, from 2,2,6,6 - tetramethyl - 4 - piperidone hindered amine light stabilizers intermediates prepared by the reaction with amines. Three-step Preparation of light stabilizers intermediate 2,2,6,6 - tetramethyl-4 - piperidine amines, mainly by the premixed reaction, dehydration, hydrogenation three-step reaction is completed. Byproduct to further reduce the product yield, high purity, post-processing to further simplify, the product has good storage stability. Stored for six months, the chroma is still standard. Since the synergistic effect of polymer light stabilizers preparation methods: the side chain at the same time with the preparation of hindered amines (HA) and o-hydroxy benzophenone (HBP) groups with the synergistic effect of polymer light stabilizers approach. It is, respectively, containing 2,2,6,6 - tetramethyl-piperidine (hindered amine-HA) and 2 - hydroxy-benzophenone (HBP) light stabilizer groups of vinyl unsaturated monomers by free radical polymerization were prepared. In polymer light stability test, obtained with the present invention polymer light stabilizers has obvious synergies