| 摘要 |
Aqueous dispersions of polyvinyl acetals are obtained by condensing a polyvinyl alcohol with an aldehyde in the presence of an acid condensation catalyst and dispersing the resultant acetal in the same operation. The aldehydes may be saturated aliphatic aldehydes containing 1 to 20 carbon atoms or aromatic aldehydes which may be nuclearly substitutes with halogen atoms or methyl or nitro groups: specified aldehydes are benzaldehyde, n-butyraldehyde, isononylaldehyde, and 2-ethylhexanal. Dispersion may be effected in the presence of natural or artificial substances of high molecular weight such as shellac, colophony glycerine ester, dammar, potato starch, tragacanth, carob bean products, polystyrenes, polyvinyl fluoride polyvinyl acetate, polyvinyl chloride, polyhexametyhlene di-adipate, polymethylene terephthalate, sulphochlorinated polyethylene, E-caprolactam, alkyd resins, a butyl-urethane-formaldehyde condensation product, a phthalic acid-polyalcohol condensation product modified with a fatty acid, nitrocellulose, phenolformaldehyde resins and cellulose ether carboxylic acids. Other substances which may be added as phenyl cogasinic sulphonic acid, phenyl-sinarol sulphonic acid, dibutyl phthalate, dibutyl terephthalate, tricresyl phosphate, para-tolune sulphonic acid, butyl acetate, glycollic acid butyl ester and butanol. The product may be converted into films. |
