Plasticized polyvinyl alcohol compositions, forming process and formed articles
OwnerGerald W. Miller, H. Harald Lutzmanninventors
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Abstract
Formed articles made from polyvinyl alcohol having an oxygen permeability of no more than about 1 cc mil/100 in.sup.2 24 hr atm. at 80% relative humidity, compositions suitable for use in manufacturing such articles and a process for manufacturing such articles by forming polyvinyl alcohol containing a non-hydroxyl plasticizer in a substantially water-free condition and cooling at a rate sufficiently slow to provide the enhanced impermeability, are disclosed.
Claims12
A process for the manufacture of a formed article of polyvinyl alcohol, said article having an oxygen permeability no greater than about 1 cc. mil/100 in..sup.2 day atm. at 25.degree. C. and 80% relative humidity, consisting essentially of:
- 1. mixing
- a. A polyvinyl alcohol homopolymer having a vinyl alcohol content in excess of 95%;
- or
- b. a blend of (a) with a polyvinyl alcohol/C.sub.2-4 olefin copolymer wherein (a) is at least 25% by weight of the mixture and the olefin moiety in the copolymer is not more than about 45% by weight of the copolymer;
- with
- c. a plasticizer selected from the group consisting of N-substituted C fatty acid amides;
- aryl, alkaryl, N-aryl aryl, N-alkaryl aryl and N-alkyl alkaryl sulfonamides and alkaryl sulfonamides;
- N-alkyl pyrrolidones;
- sulfonated alkyl phenols;
- aryl and alkaryl phosphates and phosphites;
- alkylene carbonates and selected mixtures thereof;
- 2. removing the water from the mixture so that it is essentially anhydrous and forming the dry mixture into an article;
- 3. heating the article to a temperature of at least about 200.degree. C., either concurrently with or after the forming step 2;
- and
- 4. slowly cooling the resulting article.
Dependencies are inferred from the claim text.