Method for preparing ethylene-vinyl alcohol copolymer

• Main Authors: HE YUHANG, LYU YANGCHENG, KE HUA
• Format: Patent
• Language: Chinese; English
• Published: 04.04.2023
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP

The invention discloses a method for preparing EVOH (Ethylene Vinyl Alcohol), which comprises the following steps: (1) mixing ethylene, vinyl acetate, an initiator and a methyl acetate solvent, and carrying out polymerization reaction to obtain a mixed solution containing EVA (Ethylene Vinyl Acetate); and (2) mixing the EVA-containing mixed solution, a catalyst and an alcohol substance, and carrying out alcoholysis reaction to obtain an EVOH-containing mixed solution. According to the invention, methyl acetate is adopted as a solvent for polymerization reaction, and compared with methanol as the solvent for polymerization reaction, the chain transfer capacity of methyl acetate is lower than that of methanol, the molecular weight of an intermediate product EVA is higher, the molecular weight distribution of EVA is narrower, the molecular weight of EVOH is increased, and the strength and stability of EVOH are further significantly improved; compared with tert-butyl alcohol serving as a solvent of the polymeriza