The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 12, 1985
Filed:
Dec. 16, 1983
Hans D Hermann, Bad Soden am Taunus, DE;
Ulrich M Hutten, Kelkheim, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
The invention relates to finely divided polyvinyl acetal which is prepared in the form of an aqueous suspension or, if desired, in powder form, preferably having average particle sizes from 0.5 to 10 .mu.m, from polyvinyl alcohol and at least one aliphatic aldehyde having at least 3 carbon atoms, and which contains 0.1 to 10% by weight, based on polyvinyl acetal, of a completely or partially hydrolyzed vinyl ester copolymer grafted onto polyethylene oxide or polyethylene oxide derivatives and acetalized in the mixture with the polyvinyl alcohol. The invention further relates to a process for preparing finely divided polyvinyl acetals having an average particle size between 0.5 and 10 .mu.m in an aqueous suspension or, if desired, by dewatering the suspension, in powder form, by reacting an aqueous solution of polyvinyl alcohol, in the presence of an acidic catalyst and in the absence or presence of emulsifiers, with at least one aliphatic aldehyde having at least 3 carbon atoms, which comprises performing the acetalization reaction in the presence of 0.1 to 10% by weight, based on the polyvinyl alcohol used, of a completely or partially hydrolyzed graft copolymer of vinyl ester on polyethylene oxide or polyethylene oxide derivatives. A further part of the subject-matter of the invention is the use of the finely divided polyvinyl acetals described above, in particular from a low-electrolyte or electrolyte-free aqueous suspension, preferably having an average particle size between 0.5 and 10 .mu.m, for baked coatings on any coatable substrates, in particular on metals.