US 8,163,212 B2Granted

Process for producing pellet of ethylene/vinyl alcohol copolymer

AssigneeKuraray Co., Ltd.

InventorsNaohiko Uchiumi, Noriyuki Kida, Hiroyuki Shimo, Kaoru Ikeda

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Abstract

The present invention provides a process for producing pellet of EVOH comprising the steps of introducing an EVOH solution containing alcohol into an apparatus, contacting the solution with water in the apparatus to let out the alcohol with water and then letting out an EVOH hydrous composition from the above-mentioned apparatus (step 1); cutting the EVOH hydrous composition let out therefrom to obtain EVOH hydrous composition pellets (step 2); introducing the obtained EVOH hydrous composition pellets into a dryer to reduce a water content thereof (step 3); melt-kneading the pellets, whose water content is reduced, in an extruder (step 4); and cutting EVOH discharged from the extruder to obtain the pellet of EVOH (step 5). Thus, the EVOH hydrous composition obtained by removing alcohol without deteriorating the environment can be efficiently dried, and pellets having less thermal degradation in drying and a uniform shape can be obtained.

Claims15

Dependent claims

A process for producing a pellet of an ethylene-vinyl alcohol copolymer, comprising:

(1) introducing into a vessel an ethylene-vinylalcohol copolymer solution comprising 50 parts by weight or more of an alcohol having a boiling point of 100° C. or less with respect to 100 parts by weight of an ethylene-vinylalcohol copolymer, contacting the solution with water vapor in said vessel to let out said alcohol with water vapor and then letting out from said vessel an ethylene-vinylalcohol copolymer hydrous composition containing 0 to 10 parts by weight of said alcohol and 10 to 1000 parts by weight of water with respect to 100 parts by weight of the ethylene-vinylalcohol copolymer;
(2) cutting the ethylene-vinylalcohol copolymer hydrous composition in a molten state let out from said vessel in (1), thereby obtaining ethylene-vinylalcohol copolymer hydrous composition pellets;
(3) introducing the ethylene-vinylalcohol copolymer hydrous composition pellets obtained in (2) into a dryer to reduce a water content of the pellets;
(4) melt-kneading the pellets having the water content from 0.1 to 4.5 wt. % reduced in (3), in an extruder;
and
(5) cutting the ethylene-vinylalcohol copolymer discharged from the extruder in (4), thereby obtaining the pellet of the ethylene-vinyl alcohol copolymer.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/521,468Filed 14 Jul 2003
Priority: JP 2002-21019418 Jul 2002
Published: US 2006/0108703 A125 May 2006
Granted: 24 Apr 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

C08J 3/12
Processes of treating or compounding macromolecular substances: powdering or granulating
B29B 9/06
By dividing preformed material: in the form of filamentary material, e.g. combined with extrusion
B29B 9/065
In the form of filamentary material, e.g. combined with extrusion: under-water, e.g. underwater pelletizers
B29B 9/16
Making granules: auxiliary treatment of granules