53results about How to "Improve polymerization conversion rate" patented technology

The production method of superabsorbent resin is to obtain a viscous prepolymer through prepolymerization of reaction materials such as polymerized monomers, initiating systems, and crosslinking agents, and then further polymerize to form a gel-like solid product. Water-absorbent resin products. The initiation system adopts low temperature and high temperature compound initiation system. The water absorption rate (deionized water) of the prepared superabsorbent resin product is 500-2000g / g, the absorption rate of physiological saline (0.9% NaCl aqueous solution) is 50-150g / g, the water absorption rate is less than 10 seconds, and the hydrogel formed after the resin absorbs water Has high gel strength. The entire polymerization reaction is relatively stable, the heat release is relatively dispersed, the maximum polymerization temperature is reduced, and the operating environment is improved. The invention is more suitable for the continuous conveyor belt industrial production process.

The application provides a method for preparing a methyl methacrylate polymer. The production method comprises: intermittently adding polymerization material liquid into a reactor to carry out intermittent polymerization reaction. The polymerization feed liquid comprises the first polymerized monomer and the first initiator; the mixture of the polymerized monomer feed liquid and the initiator feed liquid is continuously added to the reactor to carry out continuous polymerization reaction to obtain methyl methacrylate polymer, and the polymerization unit The bulk feed liquid includes the second polymerized monomer, and the initiator feed liquid includes the third polymerized monomer and the second initiator. This production method can realize the stable operation of bulk polymerization. At a relatively low polymerization temperature, a relatively small amount of initiator is used to obtain a relatively high polymerization conversion rate of 45% to 75%, and the polymerization residence time is shortened to 120min to 120min. 150min, improve production efficiency, and then reduce the generation of dimers, so that the content of dimers in the polymer is below 1%, and high-purity polymers are obtained.

The invention relates to acetophenone type photoinitiators using fluorene as a conjugated structure as well as a preparation method and an application of the acetophenone type photoinitiators. According to the photoinitiators, substituted acetophenone with high electron-attracting capability is taken as an electron-attracting group, and fluorene molecules with different lengths are taken as the conjugated structure and form a D-pi-A type molecule system with electron-donating triphenylamine groups. Two types of Type II photoinitiators are provided according to different conjugated structures and different acetophenone substituted positions. The synthesis steps of the photoinitiators are simple, purification is easy, the yield is high, the light absorption property is good, the photoinitiators are easy to dissolve in a monomer, the absorption peak of the photoinitiators ranges from 365 nm to 405 nm, and the photoinitiators can initiate free radical and cationic polymerization under the initiation of ultraviolet and visible light and has a faster initiation speed and very high polymerization conversion rate. Two types of photoinitiators have wide application in the field of UV photocuring.