Preparation of highly water-soluble polyvinyl alcohol

[0019] Add 79 parts of vinyl acetate monomer, 19 parts of methanol, 0.06 parts of AIBN, and 2 parts of acrylic acid into the reaction bottle, and carry out the reaction under nitrogen protection. The reaction is carried out in a reactor equipped with a thermometer, a stirrer and a reflux condenser, heated in a water bath to 65°C, and reacted for about 3 hours. The product is polyvinyl acetate, and the conversion rate of the reaction is detected; the product is calculated according to the conversion rate of polyacetic acid The amount of vinyl ester is based on the ratio of polyvinyl acetate to methanol is 70 parts / 30 parts and an appropriate amount of methanol is added to prepare a methanol solution of about 30%. Take 60 parts of 30% concentration of polyvinyl acetate methanol solution, 40 parts of sodium hydroxide / methanol solution with a concentration of 0.1g / ml, stir well, and react at 50°C for 20 minutes to obtain polyvinyl alcohol with a degree of alcoholysis of 99 . T

[0021] Add 76 parts of vinyl acetate monomer, 20 parts of methanol, and 0.06 part of AIBN to the reaction flask together, add 4 parts of acrylic acid in 5 times, and the reaction is carried out in a reactor equipped with a thermometer, agitator and reflux condenser, heated in a water bath to 63°C and react for 5 hours. Take the product and calculate the amount of polyvinyl acetate according to the conversion rate, and add an appropriate amount of methanol according to the ratio of polyvinyl acetate to methanol of 70 parts / 30 parts to prepare a methanol solution of about 30%. Take 97 parts of polyvinyl acetate methanol solution with a concentration of 30%, 3 parts of potassium hydroxide / methanol solution with a concentration of 0.1g / ml, stir evenly, and react at 50°C for 20 minutes to obtain a modified polyvinyl acetate with a degree of alcoholysis of 88. vinyl alcohol. The modified polyvinyl alcohol was placed in 100 times deionized water at room temperature and allowed to

[0023] Add 50 parts of vinyl acetate monomer, 49 parts of methanol, and 0.04 part of AIBN into the reaction flask. Under nitrogen protection, 1 part of acrylic acid is added dropwise to the reactor for reaction. In the reactor, the water bath was heated to 60 ° C, and the reaction was carried out for 6 hours. Take the product and calculate the amount of polyvinyl acetate according to the conversion rate, and add an appropriate amount of methanol according to the ratio of polyvinyl acetate to methanol of 70 parts / 30 parts to prepare a methanol solution of about 30%. Take 63 parts of polyvinyl acetate methanol solution with a concentration of 30%, 37 parts of potassium hydroxide / methanol solution with a concentration of 0.1g / ml, stir evenly, and react at 50°C for 20 minutes to obtain a modified polyvinyl acetate with a degree of alcoholysis of 99. vinyl alcohol. The modified polyvinyl alcohol is completely dissolved in 100 times 90°C deionized water within 12-15 minutes.