摘要:
A process for producing vinyl acetate polymers comprises, after polymerization of at least one monomer comprising vinyl acetate, adding a conjugated polyene having a boiling point of at least 20°C. Saponified products of the vinyl acetate polymers obtained by this process can give molded articles causing little coloring and generation of gel-like agglomerates.
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 DEG 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 DEG 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).
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:
The present invention provides a method for producing an ethylene-vinyl alcohol copolymer resin composition, said method comprising: a) introducing into an extruder an ethylene-vinyl alcohol copolymer resin having a water content of at least 0.5 weight % and an additional component; b) kneading the resin and the additional component whereby to form an ethylene-vinyl alcohol copolymer resin composition; and c) discharging said resin composition from the extruder; wherein said additional component comprises a resin selected from resins which are compatible with the ethylene-vinyl alcohol copolymer, resins having functional groups capable of reacting with the ethylene-vinyl alcohol copolymer and resins capable of dispersing in the ethylene-vinyl alcohol copolymer, wherein the amount of said additional component ranges from 5 weight parts to 200 weight parts per 100 weight parts of the ethylene-vinyl alcohol copolymer resin, and wherein said method further comprises feeding water in a liquid state to the extruder and/or removing water in a liquid state from the extruder. Thereby, strand-breakage or cutting errors are suppressed and thus molded articles such as pellets can be provided with a stable shape.
摘要:
The present invention provides a method for producing an ethylene-vinyl alcohol copolymer resin composition, said method comprising: a) introducing into an extruder an ethylene-vinyl alcohol copolymer resin having a water content of at least 0.5 weight % and an additional component; b) kneading the resin and the additional component whereby to form an ethylene-vinyl alcohol copolymer resin composition; and c) discharging said resin composition from the extruder; wherein said method further comprises feeding water in a liquid state to the extruder and/or removing water in a liquid state from the extruder. Thereby, strand-breakage or cutting errors are suppressed and thus, molded products such as pellets can be provided with a stable shape.