Since the hindered amine light stabilizer was developed in the late 1970s, due to its excellent light stability and application performance, coupled with the synergistic effect with ultraviolet absorbers and antioxidants, it has received widespread attention in the market.
At present, the hindered amine light stabilizers have a tendency of high molecular weight. Generally speaking , the increase of molecular weight can increase the HALS’ performance such as extraction resistance, migration resistance, precipitation resistance, heat resistance and reduce the loss caused by physical action. However, If the molecular weight is too high, It will affect the migration and diffusion of HALS in the polymer material, which is not conducive to the effective supplement of HALS molecules from the inside of the material to the surface. Studies have shown that if Omnistab LS 2020 is to play its best stability, its average relative molecular weight is generally controlled at 2600-3400. Compared with the average relative molecular weight of most commercial HALS products which molecular weight is about 2000, It has better UV resistance and thermal stability, lower volatility and better compatibility with polymer materials.
Moreover, the molecular weight distribution of Omnistab LS2020 is very narrow and the polydispersion is less than 1.5 ,which is very powerful to ensure the final performance of the products and durable stability in the processing and application. The light transmittance of the LS 2020 is more than 92% at 425 nm , and the light stabilizer result is 2~4 times than the traditional absorption light stabilizer. Also it is compatible with many polymer materials such as polyolefin, olefin copolymer, polyacetal, polyamide, polyurethane, soft and hard PVC or their mixtures, styrene ,special adhesives and so on. In addition , it is as nontoxic and polluting as other high-molecular-weight resistive amines such as Omnistab LS622, Omnistab LS944, Omnistab UV3346, approved by the FDA and can be directly used in food packaging materials.
The Omnistab LS2020 combines the advantages of various high molecular weight HALS, while providing higher light and thermal stability for the polymer, it is also perfectly combined with other auxiliary properties (such as small color interference, improved melt flow rate control). At present, Omnistab R&D Center is constantly testing and developing new reaction media, controlling the reaction temperature, adjusting the composition and dosage of reaction intermediates, and under the premise of meeting the molecular weight and distribution requirements, it has successfully carried out large-scale and industrial production, and its annual production capacity has reached300 tons.
Attached Table
Quality Control of Omnistab LS2020
Test item | Property requirement |
Appearance | Light yellow crystalline particles |
Melting point(℃） | 120.00-150.00 |
Volatile(%) | 1.00 max |
Molecular weight(Mn) | 2600-3400 |
Polydispersion (Mw/Mn) | 1.50max |
Clarity of Solution (1g in 20ml toluene) | Clear to opalescent solution |
Light transmittance at 425nm | 92.00 min |
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