Uniform hydrolysis catalyst addition to ethylene-vinyl ester polymers
AssigneeNational Distillers and Chemical Corporation
InventorsMichael F. Hardy, Terry Tgavalekos
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Abstract
Process for the production of partially-hydrolyzed ethylene-vinyl ester interpolymers by the controlled alcoholysis of the base resins, in which discoloration of the hydrolyzed products is suppressed by the rapid addition of the alcoholysis catalyst to the reaction medium. In reactions carried out over periods of from 0.5 to 200 minutes, the catalyst is thus added to the medium within periods of from 0.1 to 20 minutes at substantially uniform rates varying by no more than .+-.25% over the period of addition. Substantially colorless hydrolyzed resins of particular application for packaging films are thereby produced.
Claims8
In the process for the alcoholysis of an ethylene-vinyl ester interpolymer containing from 3 to 45 weight percent of vinyl ester in a reaction medium comprising as components thereof said interpolymer, a low-boiling alcohol, a hydrocarbon solvent and an alkaline or acidic catalyst, the hydrocarbon solvent and low-boiling alcohol being incorporated in the reaction medium in the proportion from about 1:5 to about 10:1 parts by volume, wherein the interpolymer is incorporated in the reaction medium in an amount of from about 20 to about 50 percent by weight of the hydrocarbon solvent and low-boiling alcohol the improvement which comprises adding the catalyst to the alcoholysis reaction medium during the reaction within a period of from about 0.1 to about 20 minutes at a substantially uniform rate which does not vary over the period of catalyst addition by more than about .+-.25% to thereby provide an alcoholyzed interpolymer in which discoloration is inhibited or suppressed.
Dependencies are inferred from the claim text.