Kuraray Co., Ltd.

Takaharu Kawahara

Toshio Tuboi

Yukihiro Ohara

Hiroshi Kawai

Masao Hikasa

Tetsuya Hikasa

Kaoru Ikeda

Naoshi Nakagawa

Takeshi Moritani

Masato Takai

Toshinori Tsugaru

Naoki Fujiwara

Toshiaki Sato

Hiroyuki Shimo

Takeshi Kusudou

Akimasa Aoyama

Edgard Chow

Yoichi Matsumoto

Etsuo Nakazato

Naoyuki Himi

Akimasa Aoyama, Deceased

Masahiro Igaki

Kouichi Takahashi

Nobutoshi Wada

To provide a resin composition comprising an ethylene-vinyl alcohol copolymer (A) having an ethylene content of from 15 to 65 mol % and a degree of saponification of 95 mol % or more, a phosphoric acid salt (B) which can form a hydrate, and a dispersing agent (C), wherein the dispersing agent (C) comprises at least one species selected from the group consisting of aliphatic acid salts, glycerol aliphatic acid esters and aliphatic acid amides, the resin composition comprises (A) and (B) in amounts of from 50 to 99 parts by weight and from 1 to 50 parts by weight, respectively, based on 100 parts by weight of (A) and (B) in total, and the resin composition comprises (C) in an amount of from 1 to 20 parts by weight based on 100 parts by weight of (B). This resin composition excels in gas barrier property and also in moisture resistance at high temperatures and high humidities. Therefore, it is suitable for food packaging containers to be retorted.

Resin composition and multilayer structure

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&#xb0; 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&#xb0; 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).

Process for producing ethylene-vinyl alcohol copolymer resin, process for producing pellets and resin pellets

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.

Method for producing ethylene-vinyl alcohol copolymer resin composition

This invention provides a method for producing a saponified ethylene-vinyl acetate copolymer in which visible imperfections (particularly fish eyes) of the saponified copolymer is inhibited. In this invention, a mixture solution is prepared by adding water to a methanol solution after saponifying an ethylene-vinyl acetate copolymer, and insoluble materials are removed from this mixture solution. Various types of filter or centrifugal separator are used to remove insoluble materials. It is preferable that the weight ratio of methanol to water is from 5:5 to 9:1, the concentration of the saponified copolymer is from 30 to 60 wt %, and the temperature is from 55 to 80&#xb0; C. This method is particularly suitable for producing a saponified ethylene-vinyl acetate copolymer having an ethylene content of 20 to 70 mol % and a saponification degree of at least 95 mol %.

Method for producing saponified ethylene-vinyl acetate copolymer

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.

Method for producing ethylene-vinyl acetate copolymer and saponified product thereof

The present invention relates to a method of producing an ethylene-vinyl alcohol copolymer resin.

Method for producing ethylene-vinyl alcohol copolymer resin

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.

Method for manufacturing ethylene-vinyl acetate copolymer and apparatus for manufacturing the same

A method for producing a saponified ethylene-vinyl acetate copolymer (EVOH) comprises: supplying into a second reactor a solution containing the copolymer that is saponified partially with an alkali catalyst under a predetermined pressure in a first reactor; and saponifying further the partially-saponified copolymer in the second reactor under a pressure higher than the predetermined pressure in the first reactor. According to the method, an EVOH having a high saponification degree can be produced efficiently with a small amount of alkali catalyst.

Method and apparatus for producing ethylene-vinyl acetate copolymer saponification product

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.

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).

This invention provides a method for producing a saponified ethylene-vinyl acetate copolymer in which visible imperfections (particularly fish eyes) of the saponified copolymer is inhibited. In this invention, a mixture solution is prepared by adding water to a methanol solution after saponifying an ethylene-vinyl acetate copolymer, and insoluble materials are removed from this mixture solution. Various types of filter or centrifugal separator are used to remove insoluble materials. It is preferable that the weight ratio of methanol to water is from 5:5 to 9:1, the concentration of the saponified copolymer is from 30 to 60 wt %, and the temperature is from 55 to 80&deg; C. This method is particularly suitable for producing a saponified ethylene-vinyl acetate copolymer having an ethylene content of 20 to 70 mol % and a saponification degree of at least 95 mol %.

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, and which provides EVOH pellets of the aqueous composition, which can be produced stably and can be washed rapidly, the method involving 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&deg; 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; and the EVOH pellets obtained by cutting the aqueous EVOH composition obtained in the method.

Method for producing aqueous ethylene-vinyl alcohol copolymer composition

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. For example, EVOH and the solution are continuously fed into a treatment apparatus and brought into contact with each other in the treatment apparatus, and the EVOH when continuously removed from the apparatus is in contact with the solution containing the boron compound in a concentration of at least 0.7 times but not more than 1.3 times a solution equilibrium concentration.

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&deg; 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.

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Okayama, Japan

Takaharu Kawahara