Since the industrial revolution, modern society has been built by consuming a large amount of fossil fuels, but on the other hand, carbon dioxide concentration in the atmosphere is increased, and further, this increase is more accelerated by environmental destruction such as disforestation, etc.
Global warming is caused by an increase of greenhouse gases such as carbon dioxide, freon, and methane in the atmosphere, such that it is significantly important to reduce the atmospheric concentration of carbon dioxide highly contributing to global warming, and several studies into emission regulation, immobilization, etc., have been conducted on a global scale.
Among the studies, a copolymerization of carbon dioxide and epoxide developed by Inoue, et al., is expected as a reaction for solving the problems of global warming, and has been actively researched in view of immobilization of chemical carbon dioxide and in view of the use of carbon dioxide as a carbon resource.
Particularly, a polyalkylene carbonate resin obtained by the copolymerization of carbon dioxide and epoxide has recently received significant attention as a kind of biodegradable resins.
Various catalysts for manufacturing the polyalkylene carbonate resin have been researched and suggested for a long time, and as representative examples thereof, zinc dicarboxylate-based catalysts such as a zinc glutarate catalyst, etc., in which zinc and dicarboxylic acid are combined to each other have been known.
Meanwhile, the zinc dicarboxylate-based catalyst, as a representative example, a zinc glutarate catalyst is formed by reacting a zinc precursor with a dicarboxylic acid such as a glutaric acid, etc., and has a shape of fine crystalline particle.
However, the crystalline particle shaped zinc dicarboxylate-based catalyst has many cases in which agglomeration among the catalyst particles occurs in a polymerization process, etc.
In the case where the agglomeration among the catalyst particles occurs, there is a drawback in which if a polymerization process for manufacturing a polyalkylene carbonate resin is performed, a sufficient contact area between reactants and the catalyst is not secured, such that a polymerization activity by the catalyst is not sufficiently expressed.
Due to the drawback, development of a technology which is possible to manufacture a polyalkylene carbonate resin while maintaining an excellent catalytic activity by suppressing agglomeration among catalyst particles during a polymerization process, has been continuously demanded.
USPTO Backgrounds
USPTO Backgrounds