Verfahren zur Herstellung modifizierter Polyvinylacetale bzw. Polyvinylketale

摘要

940,199. Acetalized and ketalized graft copolymers. FARBWERKE HOECHST A.G. Jan. 25, 1960 [Jan. 24, 1959], No. 2730/60. Heading C3G. Modified polyvinyl acetals or ketals are obtained by: (a) polymerizing at least one vinyl ester with a polyalkylene glycol or derivative thereof and simultaneously hydrolyzing the product and reacting it with an aldehyde or ketone, or (b) reacting an aldehyde or ketone with the polyvinyl alcohol obtained by hydrolyzing the product obtained by polymerizing at least one vinyl ester with a polyalkylene glycol or derivative thereof. Suitable starting polymers are those described in Specifications 922,457, 922,458, 935,246 and 935,247. Aldehydes and ketones specified are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, benzaldehyde, nitrobenzaldehyde, salicylic aldehyde, methyl ethyl ketone and cyclohexanone. The examples describe the following processes: (1) Simultaneously hydrolyzing and reacting with formaldehyde a graft copolymer of vinyl acetate and polyethylene glycol; (2) reacting with butyraldehyde a graft copolymer of polyvinyl alcohol and hydroxy propylated tributyl phenol; (3) reacting with butyraldehyde a graft copolymer of polyvinyl alcohol and polypropylene glycol; and (4) simultaneously hydrolysing and reacting with acetaldehyde a graft copolymer of vinyl acetate and polyethylene glycol. The product of (2) may be combined with a phenol-formaldehyde resin to make a baking lacquer.