Verfahren zur Herstellung von modifizierten Polyvinylalkoholen

摘要

Polyvinyl alcohol is obtained by polymerizing a vinyl ester in the presence of a partially halogenated or an unhalogenated aliphatic hydrocarbon or a partially halogenated or unhalogenated cycloaliphatic hydrocarbon of either low or high molecular weight and containing at least 5 carbon atoms or in the presence of a mixture of said hydrocarbons and then hydrolysing the polyvinyl ester so obtained after removal of the unreacted monomer in an alkaline or acid medium. The hydrocarbons may be petroleum fractions having a boiling point of at least 40 DEG C. under atmospheric pressure, petroleum ethers, wax-like to solid acyclic paraffins, cycloparaffins such as 1:4-dimethylcyclohexane, polymers of olefines and diolefines including ethylene, propylene and butadiene. Halogen containing derivatives containing up to 60% of a halogen may also be used. Preferably the product contains 0,1 to 20% of the additive. A solution promoter such as benzene, xylene, monochlorobenzene, or dichlorobenzene may also be added, and polymerization carried out with the use of benzoyl peroxide, diacetyl peroxide, or by the action of light, or at a temperature of 60 DEG -150 DEG C. The polyvinyl alcohols may be used as dispersing agents, emulsifiers and wetting agents.