Preparation of polyvinyl alcohol and its butyral

The preparation method of polyvinyl alcohol and its butyral is as follows: water-soluble polyvinyl butyral (WPVB) was prepared by water-based grafting modification of polyvinyl butyral (PVB) with phthalic anhydride. The structure of WPVB was characterized by IR and 1HNMR, and the influencing factors of the reaction were discussed. The better technological conditions were obtained: reaction temperature 60℃, reaction time 6 h, and the amount of tetrabutylammonium bromide was 0.6% of the total mass of the feed. Preparation of WPVB aqueous dispersion. Compared with PVB, the glass transition temperature of WPVB cured coating decreased by 1 1.6℃, the total weight loss rate decreased by 3.92%, the hardness changed from 5 H to 7 H, and the adhesion changed from 1 to 0.