摘要:
In the present invention, particles of an ethylene-vinyl alcohol copolymer (EVOH) are contacted with a solution containing a boron compound, whereby to obtain a substantially homogeneous distribution of the boron compound within the particles.
摘要:
The present invention provides a method for manufacturing an ethylene-vinyl acetate copolymer (EVA) in a polymerization solution in a vessel. The polymerization solution includes ethylene, vinyl acetate, methanol and a polymerization initiator. This method includes: cooling a gas including a vapor evaporated from the polymerization solution whereby to produce a condensate of at least a portion of said gas, and introducing said condensate into the polymerization solution whereby to evaporate at least one component in said condensate. Said vapor includes said at least one component.
摘要:
Provided is a method for producing an aqueous ethylene-vinyl alcohol copolymer (EVOH) composition that ensures efficient removal of alcohol not worsening the environment in and around working areas. Also provided are EVOH pellets of the aqueous composition, which can be produced stably and can be washed rapidly. The production method comprises introducing an EVOH solution that contains at least 50 parts by weight, relative to 100 parts by weight of EVOH therein, of an alcohol having a boiling point of not higher than 100°C, into a vessel, and contacting it with water vapor in the vessel, thereby letting the alcohol out along with water vapor and taking the resulting aqueous EVOH composition that contains from 0 to 10 parts by weight of the alcohol and from 10 to 500 parts by weight of water, relative to 100 parts by weight of EVOH therein, out of the vessel. The EVOH pellets are obtained by cutting the aqueous EVOH composition obtained in the production method.
摘要:
The present invention provides methods for producing an ethylene-vinyl acetate copolymer and a saponified product thereof that can inhibit visible imperfections (particularly discoloration) at the time of molding by improving the process for recovering vinyl acetate. When the alcohol-based solvent to be blown in when recovering vinyl acetate is deoxidized so that its oxygen concentration becomes not more than 60 ppm, discoloration of a molded product of the above saponified product due to oxygen can be inhibited.
摘要:
A method for producing an ethylene-vinyl alcohol copolymer resin composition, said method comprising: (a) introducing into an extruder an ethylene-vinyl alcohol copolymer having a water content of at least 0.5 wt%; (b) further introducing into said extruder a liquid component comprising an aqueous solution of a resin, an aqueous dispersion of a resin, an aqueous dispersion of inorganic fine particles, or a mixture thereof; (c) subjecting said copolymer and said component to melt-kneading in said extruder; and (d) discharging the resulting ethylene-vinyl alcohol copolymer resin composition from the extruder. This method improves the dispersibility of a resin and/or inorganic fine particles in the EVOH while suppressing thermal deterioration of the EVOH.
摘要:
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).