November 25, 2021

Hindered Amine Light Stabilizers

Hindered amine light stabilizers (HALS) are one of the most important thermal/light stabilizing agents of polymeric materials due to their excellent compatibility and photo-stabilization effect on organic materials. The synthetic technologies of hindered amine light stabilizers 5529 and 5513 were established in this paper. Through deeply systematic research, domestic technical difficulties in hindered amine light stabilizers 5529 industrial productions in taking off impurities and decolorization have been resolved, establishing the production technology of high quality 5529 and conducting industrial production practice. Based on the investigation of the transesterification between dimethyl sebacate and 1,2,2,6,6-pentamethyl-4-piperonal, the synthetic technologies of the Solvent method and free solvent method were established in the second chapter. The hindered amine light stabilizers 5529 were obtained in the yield of97.9% and 97.6% respectively and qualified as the advanced level of the kindred overseas products.

Whether natural or synthetic polymers, in addition as well as in the process of use are inevitably exposed to sunlight or strong fluorescence, resulting in their physical properties will be significantly reduced. Such as cotton, hemp, natural silk fabrics in the wear or use of a longer time, the color will appear yellowing, discoloration, brittle, and synthetic polymers will appear cracking, transparency decline, this phenomenon is called light aging. Photo-aging of polymers is the result of the combined effect of light and oxygen in the air, and photo-aging starts from the "birth" of the polymer, with the ultimate consequence of shortening the life of the polymer. Therefore, the study of methods to prevent photodegradation of polymers has become an important research topic in the polymer materials industry. One is to change the polymer at the molecular structure level to synthesize a polymer with a stable structure resistant to photo-oxidative aging, but this approach has received less attention because of the many problems involved and the less-than-ideal results. The other is to add various light stabilizers directly to the polymer. This is the most effective method in the process of practical practice.

With the rapid development of the global synthetic rubber and plastic industry, domestic and foreign research on light stabilizers in polymer materials has become a hot topic. There are a wide variety of light stabilizers, and the commonly used light stabilizers are divided into four categories according to the mechanism of action: light-shielding agents, UV absorbers, quenching agents, and hindered amine light stabilizers. In particular, hindered amine light stabilizers have received widespread attention since their introduction due to their outstanding light stabilizer properties.

Hindered Amine Light Stabilizers (HALS) is a new class of high-efficiency stabilizers, is a class of polymer materials developed in the mid-1970s to prevent light aging of light stabilizers, because its light stabilization effect is better than UV absorbers, quenching agents, and other traditional light stabilizers several times, and with the synergistic effect of UV absorbers and antioxidants will be produced to enhance the anti-aging ability, and at the same time with many polymer compatibilities is very good, is currently the most rapidly developing class of stabilizers.

Today's hindered amine The research work of hindered amine light stabilizers is still very active, its main research direction in addition to polymer quantification, but also toward low alkali The main research direction, in addition to polymer quantification, but also towards low alkali, multi-functionalization, and other directions.

In recent years, to improve its light stability performance, domestic and foreign research on the development of new hindered amine light stabilizer, hindered amine light stabilizer performance and function have become more and more perfect, production costs have become more affordable, many new high-performance hindered amine light stabilizer was opened and put on the market.

Many new high-performance hindered amine light stabilizers have been opened and put on the market, and their development mainly shows the development trend of polymer quantification, low alkali, and multifunctional type.

Along with the development of the world's rubber and plastic products industry, light stabilizers have become the world's fastest-growing plastic additives. According to statistics, the average annual growth rate of global light stabilizer consumption from 2009 to 2013 is about 6%, of which North America, Western Europe, China, and Japan are the main consumer countries and regions. The consumption of light stabilizers in these regions accounted for 20%, 25%, and 20% of the total global consumption, respectively. These regions accounted for 20%, 25%, 15%, and 8% of the total global consumption of light stabilizers, and all other regions and countries together accounted for 32% of the total global consumption of light stabilizers. All other regions together account for 32% of global consumption.

Polymeric high molecular weight is the development direction of hindered amine light stabilizers, but part of the low molecular weight of hindered amine light stabilizers because of its process after so many years of research and practice has been more mature, and its high-cost performance, so it is still in

Hindered amine light stabilizer market occupies an important position.

At present, the development of domestic hindered amine light stabilizers, especially the excellent non-polymeric low molecular weight hindered amine light stabilizer research has been relatively rapid development. But now the domestic non-polymeric hindered amine light stabilizer process, technology research mostly stops at a shallow level.

However, the process and technology research of non-polymeric hindered amine light stabilizers in China nowadays are mostly stopped at a shallow level, and few R&D institutions or enterprises have made improvements on the existing basis. With the increasing competition in the light stabilizer industry, the search for a new energy-saving and significantly improve production rate of the production process or technology will be of potential value to improve the economic value of traditional non-polymeric light stabilizers and market competitiveness.

Hindered Amine Light Stabilizer 5529, marketed as Tinuvin 292, is an excellent low alkaline, low molecular weight liquid hindered amine light stabilizer developed by Swiss Sparkle. The light stabilizer consists of a mixture of 1-methyl-8-(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate (referred to as monoester) and bis(1,2,2,6,6-pentamethyl-4 piperidinyl) sebacate (referred to as diester) in a certain ratio (hereinafter referred to as mono-diester mixture), which is a light yellow viscous liquid with a melting point of 20 ºC and a boiling point of 220 ºC. 220 ºC, can be used in polyethylene, polypropylene, polystyrene, ABS, and various engineering plastics.

Because the mono-double ester mixture can be better dissolved in organic solvents, it is widely used in coatings, inks, and other fields, and still occupies a very important position in the market of hindered amine light stabilizers. The light stabilizer can effectively protect the coating so that the coating is in the sunburst to maintain the gloss, to prevent the coating from cracking and producing spots, to avoid the coating surface peeling, thus greatly improving the life of the coating. Domestic research units and enterprises have conducted extensive research on it, but the current domestic manufacturers of the product still have unstable product quality, product performance compared to foreign countries have a certain gap, the product production process is backward, wastewater and energy consumption, low production capacity and other problems, far from meeting the domestic market demand, a large part of the domestic market is still occupied by foreign enterprises. Therefore, a systematic study on the synthesis of 5529 is of great socio-economic value.

The common methods for the synthesis of hindered amine light stabilizer 5529 include direct esterification and ester exchange methods.

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