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AssigneeKuraray Co., Ltd.
InventorsTakaharu Kawahara, Hiroshi Kawai, Toshio Tuboi, Yukihiro Ohara, Masao Hikasa
Estimating the term…
A process for producing an ethylene-vinyl alcohol copolymer resin, including feeding EVOH into an extruder, keeping the temperature of the melting resin in the extruder at 70 to 170° C., adjusting the amount of water in the extruder so that the water content right after being discharged from the extruder is 5 to 40 weight %, and extruding out the EVOH resin. The extruded EVOH resin is cut into EVOH pellets. Thereby, it is possible to obtain resin pellets in which no spherocrystals are observed in the center of the cross section of the resin when the cross section is observed by the use of a polarization microscope, or no lubricant is contained in the resin pellets, and the angle of repose is 23° or less when the resin pellets are laminated. Thus, it is possible to provide an ethylene-vinyl alcohol copolymer (EVOH) resin pellet having a reduced discharging load to the environment and capable of being fed into an extruder smoothly without being blocked, extruding stability, and thermal stability (long-run property).
A process for producing an ethylene-vinyl alcohol copolymer resin, comprising
A process for producing ethylene-vinyl alcohol copolymer resin pellets, comprising feeding an ethylene-vinyl alcohol copolymer into an extruder to form a molten resin,
An ethylene-vinyl alcohol copolymer resin pellet, produced by feeding an ethylene-vinyl alcohol copolymer into an extruder to form a molten resin, keeping the temperature of the molten resin in the extruder at 70 to 170° C., adding at least one additive selected from the group consisting of a carboxylic acid, a boron compound, a phosphoric acid compound an alkali metal salt, and an alkali earth metal salt to the molten resin in the extruder, adjusting an amount of water present in the extruder by supplying or removing water, discharging the resin from the extruder, wherein the resin has a water content right after being discharged of 5 to 40 weight %, and then cutting the discharged ethylene-vinyl alcohol copolymer resin to form resin pellets and drying the resin pellets until the water content is 1 weight % or less, wherein no spherocrystals are observed in the center of the cross section of the resin pellet when the cross section is observed with a polarization microscope having a magnification of 600.
An ethylene-vinyl alcohol copolymer resin pellet, produced by feeding an ethylene-vinyl alcohol copolymer into an extruder to form a molten resin, keeping the temperature of the molten resin in the extruder at 70 to 170° C., adding at least one additive selected from the group consisting of a carboxylic acid, a boron compound, a phosphoric acid compound, an alkali metal salt, and an alkali earth metal salt to the molten resin in the extruder, adjusting an amount of water present in the extruder by supplying or removing water, discharging the resin from the extruder, wherein the resin has a water content right after being discharged of 5 to 40 weight %, and then cutting the discharged ethylene-vinyl alcohol copolymer resin to form resin pellets and drying the resin pellets until the water content is 1 weight % or less, wherein the angle of repose is 23° or less when the resin pellets are piled.
Dependencies are inferred from the claim text.