UV absorber is a plastic additive stabilizer that acts as a light stabilizer, producing a stabilizing effect by absorbing and converting the destructive ultraviolet light in sunlight. UV absorbers are sometimes added to the film of packaged food to suppress the effect of ultraviolet light on the packaged items.
In general, if UV absorbers are not added to the film, it will become brittle after two months of outdoor use. However, after adding UV absorbers, the elongation of the film will begin to sharply decrease after thirteen months, and the service life of the film can also reach more than one year. It is necessary to add ultraviolet absorbers to agricultural films. Experiments have shown that when the amount of ultraviolet absorbent added is 0.2 parts. The exposure time of the film can be extended by about three months to one year (depending on the specific formula design). Commonly used UV absorbers include benzophenones, benzotriazoles, triazines, and salicylates.
Only a narrow range of light waves in sunlight can degrade polychlorinated Z-ene, and the most harmful is the light wave with a wavelength of 30 nanometers, which is the central wavelength of ultraviolet light.
In practice, it has been proven that under the condition of a dosage of 0.3 parts, the absorption effect of triazine type ultraviolet absorbers is much better than that of UV 9, which can be clearly seen from the spectrogram of the film in the ultraviolet region.
Among the several commonly used plastic additives and UV absorbers introduced in the table above, UV 531, UV-9, UV-P, TBS, RMB, etc. have significant light stabilization effects, generally able to withstand outdoor exposure for about fifteen months on the film. The photostability effect of triazine is more prominent. Triazine, UV 531, UV-9, UV-P, and UV-0 have strong absorption of light waves with wavelengths ranging from 290 to 340 nanometers, and their transmittance is all below 15%. BAD has excellent weather resistance, with a film elongation of 80% even after 19 months of exposure, and no spots have appeared after 20 months of exposure. In summary, UV absorbers have the best effect, including substances that can transform into substances that can absorb UV rays under the action of light. H. The ability of P.T and salicylic acid phenyl ester to absorb ultraviolet rays is weak, and their light stability is poor. However, they still have a certain light resistance effect, and they produce spots after being exposed to sunlight for one year. TBS and RMB also have weak UV absorption ability, but have good weather resistance. Spots only appear after 15 months of exposure to sunlight. This is due to the rearrangement of 2,4- hydroxybenzophenone, which has strong UV absorption under the action of light.
Source: Global Plasticization Network
Source: Global Plasticization Network