Saponified ethylene-vinyl acetate copolymer pellets and method for their production
First Claim
1. A process for producing pellets of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 20 to 60 mol % and a saponification degree of not less than 90 mol % which comprisesintroducing a solution of said saponified ethylene-vinyl acetate copolymer (EVOH) in a solvent into a solidification bath so as to form a precipitate, separating the precipitate from the bath, and drying the resulting precipitate to form pellets, wherein the solvent in said solution of saponified ethylene-vinyl acetate copolymer EVOH is a mixture of water and alcohol in a weight ratio of 80/20 to 2/98 and satisfying the relation of
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Abstract
The invention provides pellets of a saponified ethylene-vinyl acetate copolymer which are excellent in feedability, cause little fluctuation of extruder torque or discharge during molding, and yield shaped articles with high dimensional accuracy such as the high accuracy of form and thickness. The pellets of the invention are such that the differential curve representing the magnitude of change in the cumulative pore volume curve generated by measuring the fractional volume of surface pores by the mercury intrusion method has no peak within the pore diameter range of 1×102˜1×104 Å.
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1 Claim
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1. A process for producing pellets of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 20 to 60 mol % and a saponification degree of not less than 90 mol % which comprises
introducing a solution of said saponified ethylene-vinyl acetate copolymer (EVOH) in a solvent into a solidification bath so as to form a precipitate, separating the precipitate from the bath, and drying the resulting precipitate to form pellets, wherein the solvent in said solution of saponified ethylene-vinyl acetate copolymer EVOH is a mixture of water and alcohol in a weight ratio of 80/20 to 2/98 and satisfying the relation of
Specification
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Current AssigneeNippon Gohsei Kagaku Kogyo Kabushiki Kaisha
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Original AssigneeNippon Gohsei Kagaku Kogyo Kabushiki Kaisha
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InventorsMatsui, Ikko, Kunieda, Makoto, Ninomiya, Kenji
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Primary Examiner(s)Reddick, Judy M.
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Application NumberUS09/425,729Time in Patent Office1,404 DaysField of Search525/61, 264/118, 264/143, 264/185, 264/28US Class Current264/185CPC Class CodesB29C 48/00 Extrusion moulding, i.e. ex...C08J 2323/08 Copolymers of ethene C08J23...C08J 2329/04 Polyvinyl alcohol; Partiall...C08J 3/14 by precipitation from solut...
