Porous Pellets of Ethylene-Vinyl Alcohol Copolymer, and Method for Producing Same
AssigneeKuraray Co., Ltd.
InventorMizuko Oshita
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Abstract
Provided are: porous pellets of an EVOH; and a method for producing the same, which can be accompanied by not only washing out of saponification residues in a shorter period of time, but also inhibiting conglutination of the pellets with one another during washing at a high temperature. Porous pellets of an ethylene-vinyl alcohol copolymer having pores, wherein in the porous pellets, a proportion (V2/V1×100) of a total value (V2) of pore volumes of pores having pore diameters of 0.5 to 100 μm with respect to a total value (V1) of pore volumes of pores having pore diameters of 0.005 to 100 μm is 25 to 40% by volume, and a pore surface area of pores having pore diameters of 0.005 to 100 μm is 25 to 45 m2/g.
Claims7
Porous pellets of an ethylene-vinyl alcohol copolymer comprising pores, wherein in the porous pellets,
- a proportion (V2/V1×100) of a total value (V2) of pore volumes of pores having pore diameters of 0.5 to 100 μm with respect to a total value (V1) of pore volumes of pores having pore diameters of 0.005 to 100 μm is 25 to 40% by volume, and
- a pore surface area of pores having pore diameters of 0.005 to 100 μm is 25 to 45 m2/g.
A method for producing porous pellets of an ethylene-vinyl alcohol copolymer, the method comprising:
- a first step of introducing into an extruder and melt kneading a water-containing ethylene-vinyl alcohol copolymer having a moisture content W1 of 10 to 90% by mass;
- and
- a second step of cutting the water-containing ethylene-vinyl alcohol copolymer discharged from the extruder to obtain the porous pellets of the ethylene-vinyl alcohol copolymer comprising water, wherein
- a temperature of the water-containing ethylene-vinyl alcohol copolymer discharged from the extruder is 80 to 100° C.,
- a proportion (V2/V1×100) of a total value (V2) of pore volumes of pores having pore diameters of 0.5 to 100 μm with respect to a total value (V1) of pore volumes of pores having pore diameters of 0.005 to 100 μm, in the porous pellets of the ethylene-vinyl alcohol copolymer, is 25 to 40% by volume, and
- a pore surface area of the porous pellets of the ethylene-vinyl alcohol copolymer is 25 to 45 m2/g.
Dependencies are inferred from the claim text.