Abstract: 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.

Abstract: 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.

Abstract: Provided is a method for producing an ethylene-vinyl alcohol copolymer resin that ensures efficient removal of alcohol without worsening the working environment. The method comprises introducing an ethylene-vinyl alcohol copolymer solution containing at least 50 parts by weight of an alcohol having a boiling point of not higher than 100° C., relative to 100 parts by weight of the ethylene-vinyl alcohol copolymer therein, into an apparatus, and contacting it with water in the apparatus, thereby letting the alcohol along with water out of the apparatus and taking the resulting aqueous ethylene-vinyl alcohol copolymer composition that contains from 0 to 10 parts by weight of the alcohol and from 10 to 1000 parts by weight of water, relative to 100 parts by weight of the ethylene-vinyl alcohol copolymer therein, (step 1), and a step of feeding the aqueous ethylene-vinyl alcohol copolymer composition into an extruder, kneading it in melt therein, and then extruding the copolymer out of the extruder (step 2).

Abstract: 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.

Abstract: 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° 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 %.

Abstract: 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.

Abstract: 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° 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.

Abstract: 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.

Abstract: A vinyl alcohol polymer with a side chain being a hydroxyalkyl group having 2 to 20 carbon atoms is disclosed. Conventional water-soluble vinyl alcohol polymers gives, where they have a high interfacial activity, an aqueous solution with much-foaming and hence a problem when used for commercial purposes. On the other hand, the vinyl alcohol polymer of the present invention gives, where it is water-soluble, an aqueous solution with less-foaming in spite of its high interfacial activity, and hence an excellent industrial applicability. The vinyl alcohol polymer of the present invention is useful as thermoplastic resin and dispersion stabilizer. In addition, the vinyl alcohol polymer of the present invention is usable for various purposes, e.g.

Abstract: 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.degree. 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.