JP2005042002A - Film or sheet, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film or sheet comprising an EVOH resin composition hardly generating stench; and to provide a production process of the sheet or the film, having excellent long-run performance and obtained by considering the environment. <P>SOLUTION: The film or the sheet is produced by bringing an ethylene-vinyl alcohol copolymer resin into contact with an aqueous solution containing at least one kind of additives selected from the group consisting of (A) an alkali metal salt and (B) a boron compound, and carbon dioxide gas, and subjecting the resultant resin to extrusion molding. In a suitable aspect, a multilayer structure is obtained by coextrusion molding with other thermoplastic resins, and the multilayer structure is subjected to thermoforming. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a film or sheet comprising an ethylene-vinyl alcohol copolymer resin composition, and a method for producing the film or sheet. Moreover, it is related with the melt-molded article which consists of an ethylene-vinyl alcohol copolymer resin composition.

  An ethylene-vinyl alcohol copolymer (hereinafter sometimes abbreviated as EVOH) is a useful polymer material excellent in oxygen shielding properties, oil resistance, non-charging properties, mechanical strength, etc. It is widely used as various packaging materials such as containers. There are various methods for forming EVOH pellets into various molded products, but they are often melt-kneaded and extruded. However, since the melting temperature usually has to be 200 ° C. or higher during molding of EVOH resin, EVOH containing no additives is likely to deteriorate during extrusion molding, causing fish eyes and blisters to the product and reducing the quality. There was sometimes. In addition, it is necessary to add an additive in order to improve the interlaminar adhesion at the time of use with another resin.

  WO99 / 05213 pamphlet (US Pat. No. 6,174,949) includes at least one selected from a boron compound as an essential component, acetic acid as an optional component, and an acetate and a phosphate compound as an essential component. The content of each component with respect to 100 parts by weight of EVOH, the boron compound is 0.001 to 1 part by weight in terms of boron, the acetic acid is 0 to 0.05 parts by weight, and the acetate is 0 in terms of metal. An EVOH resin composition in which 0.001 to 0.05 parts by weight and the phosphoric acid compound is 0.0005 to 0.05 parts by weight in terms of phosphate group is described. This resin composition is said to be an EVOH resin composition with improved long run properties, appearance, and interlayer adhesion. Here, it is described that the purpose of blending acetate is to improve long run properties and interlayer adhesion.

  Japanese Patent Application Laid-Open No. 2001-164059 (European Patent Application Publication No. 1090953) is an EVOH resin composition characterized in that the MFR exhibits a specific behavior when the resin composition is heated and melted. Carboxylic acid having a molecular weight of less than 75 is 50 to 500 ppm, alkali metal salt is 50 to 500 ppm in terms of metal element, alkaline earth metal salt is 10 to 120 ppm in terms of metal element, phosphate compound is 10 to 200 ppm in terms of phosphate radical, A resin composition containing 50 to 2000 ppm of a boron compound in terms of boron element is described. This resin composition is said to be an EVOH resin composition that is excellent in appearance and long run property during melt molding, little colored during recovery, and excellent in interlayer adhesion when formed into a laminate. Here, an alkali metal salt is added to improve interlayer adhesion, and a boron compound is added to improve long-run properties.

  As a method for producing EVOH pellets containing the additive, a method in which EVOH hydrous pellets are brought into contact with an aqueous solution containing the additive is described as a representative method. According to this method, it is easy to control the amount of trace components contained in the EVOH pellets by adjusting the solution concentration, and it is possible to obtain stable quality pellets by drying after contacting with the aqueous solution.

  As described above, in order to improve interlayer adhesion, an alkali metal salt is added to the EVOH resin, and is typically added as an acetate salt. In many cases, acetic acid not forming a salt is also added at the same time. However, the EVOH resin composition containing an acetate group in this way sometimes gives off an acetic acid odor. One of the main uses of the EVOH resin composition is a food packaging container, and there has been a demand for an EVOH resin composition with less odor generation in the market. Further, an EVOH resin composition having improved melt stability and excellent long run properties is desired.

  On the other hand, when EVOH hydrous pellets are brought into contact with an aqueous solution containing acetic acid or acetate to produce EVOH resin composition pellets, acetic acid is released into the atmosphere when the hydrous pellets after contact are dried. In many cases, the surrounding environment and work environment may be adversely affected.

International Publication No. 99/05213 Pamphlet JP 2001-164059 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a sheet or film made of an EVOH resin composition that is suitable for food packaging applications and the like that generate little odor. It is another object of the present invention to provide a melt-molded product comprising such an EVOH resin composition. Furthermore, it is an object of the present invention to provide a method for producing a sheet or film having improved melt stability and excellent long run properties. According to the production method of the present invention, the above EVOH resin composition is produced. It is possible to provide an environment-friendly manufacturing process that does not discharge carboxylic acid such as acetic acid to the surrounding environment during molding.

  The said subject contains 0.1-20 micromol / g of alkali metal salt (A) in conversion of an alkali metal, and 0-2 micromol / g of carboxylic acid root (C1) extracted by immersing in 95 degreeC water for 10 hours. And an ethylene-vinyl alcohol copolymer resin composition containing 0 to 40 μmol / g of carboxylic acid radical (C2) extracted by immersion in a 0.05 N aqueous sodium hydroxide solution at 95 ° C. for 10 hours. It is solved by providing a film or sheet.

  The said subject contains 0.1-20 micromol / g of alkali metal salt (A) in conversion of an alkali metal, and 0-2 micromol / g of carboxylic acid root (C1) extracted by immersing in 95 degreeC water for 10 hours. It is also solved by providing a film or sheet comprising an ethylene-vinyl alcohol copolymer resin composition that contains and has a saponification degree of 99.7 to 100 mol%.

  Further, the above problem is that the ratio (d / t) between the content (d: μmol / g) of the phosphate compound (D) in terms of phosphate radicals and the phosphorus element content (t: μmol / g) is 0. It is also solved by providing a film or sheet comprising an ethylene-vinyl alcohol copolymer resin composition that is 4 or less and substantially does not contain an organophosphorus compound extractable with chloroform.

  In these films or sheets, the alkali metal salt (A) contains a potassium salt in an amount of 0.1 to 20 μmol / g in terms of potassium, and the boron compound (B) in an amount of 1 to 200 μmol / g in terms of a boron element. And the phosphorus element content (t) is preferably 0.05 to 5 μmol / g in terms of phosphorus element.

  A film or sheet comprising a multilayer structure having a layer of the ethylene-vinyl alcohol copolymer resin composition and another resin layer is a preferred embodiment of the present invention. A molded product formed by thermoforming the film or sheet is also a preferred embodiment of the present invention.

  Moreover, the said subject is an ethylene-vinyl alcohol copolymer in the aqueous solution containing the at least 1 sort (s) of additive selected from the group which consists of an alkali metal salt (A) and a boron compound (B), and containing a carbon dioxide gas. It is also solved by providing a method for producing a film or sheet in which the resin is brought into contact and then extruded. At this time, co-extrusion with another thermoplastic resin is a preferred embodiment.

  Furthermore, the above problem is that the ratio (d / t) between the content (d: μmol / g) of the phosphate compound (D) in terms of phosphate radicals and the phosphorus element content (t: μmol / g) is high. It can also be solved by providing a melt-molded product comprising an ethylene-vinyl alcohol copolymer resin composition that is 0.4 or less and substantially does not contain an organic phosphorus compound that can be extracted with chloroform.

  The sheet or film of the present invention generates little odor and is suitable for food packaging applications. Moreover, since the EVOH resin composition used in the present invention has improved melt stability and excellent long run properties, it becomes easy to obtain a sheet or film having a good appearance. Moreover, the EVOH resin composition used in the present invention does not discharge carboxylic acid such as acetic acid to the surrounding environment when it is manufactured and molded into a sheet or film, and an environmentally friendly manufacturing process is performed. Can be provided.

  First, the manufacturing method of the EVOH resin composition used by this invention is demonstrated. A suitable production method includes an ethylene-vinyl alcohol copolymer in an aqueous solution containing at least one additive selected from the group consisting of an alkali metal salt (A) and a boron compound (B) and containing carbon dioxide gas. It is a manufacturing method of the ethylene-vinyl alcohol copolymer resin composition which makes resin contact.

  Conventionally, in order to make an EVOH resin contain at least one additive selected from the group consisting of an alkali metal salt (A) and a boron compound (B), EVOH is brought into contact with an aqueous solution containing these additives. The way was done. In addition to this, the EVOH resin composition used in the present invention is further brought into contact with an aqueous solution containing carbon dioxide gas.

  In order to improve interlayer adhesion in a multilayer structure including an EVOH layer, the EVOH resin composition preferably contains an alkali metal salt (A). Therefore, the alkali metal salt (A), particularly an alkali metal acetate, is preferable. In many cases, the EVOH resin is immersed in an aqueous solution containing selenium. At this time, if the liquid to be immersed is kept alkaline, the stability at the time of melt molding is often lowered, and in order to solve this problem, an acid, particularly a carboxylic acid typified by acetic acid, is often contained separately.

  However, when the content of carboxylic acid radicals derived from carboxylic acids and carboxylates is high, the EVOH resin composition often generates a carboxylic acid odor, which may be a problem when used for food packaging applications. was there. In addition, there has been a problem that carboxylic acid is released to the surrounding environment when it is dried after being brought into contact with an aqueous solution containing an additive. Accordingly, there has been a demand for a method that does not make the aqueous solution containing the additive alkaline, while containing the alkali metal salt (A) and minimizing the content of carboxylic acid radicals. The resin composition used in the present invention can solve this problem by containing carbon dioxide gas in an aqueous solution containing an alkali metal salt (A).

  Moreover, in order to improve the long run property at the time of melt-molding the EVOH resin composition, it is desirable to add the boron compound (B), so that the EVOH resin is immersed in an aqueous solution containing the boron compound (B). There were many things. However, depending on the application, even if the boron compound (B) is contained, the long run property may still be insufficient, and further improvements are desired.

  The EVOH resin composition used in the present invention can be further improved by adding carbon dioxide gas to an aqueous solution containing a boron compound (B). That is, it is possible to obtain an EVOH resin composition having excellent long-run properties by reducing the content of the carboxylic acid radical using an aqueous solution containing carbon dioxide gas and further adding a boron compound (B). It will be.

  As EVOH used in the present invention, those obtained by saponifying an ethylene-vinyl ester copolymer are preferable, and those obtained by saponifying an ethylene-vinyl acetate copolymer are particularly preferable. From the viewpoint of obtaining a molded article excellent in gas barrier properties and melt moldability, the ethylene content is preferably 5 to 60 mol%. When the ethylene content is less than 5 mol%, the melt moldability may be deteriorated, and when the ethylene content exceeds 60 mol%, the gas barrier property may be insufficient. The lower limit of the ethylene content is more preferably 15 mol% or more, and even more preferably 20 mol% or more. On the other hand, the upper limit of the ethylene content is more preferably 55 mol% or less, and even more preferably 50 mol% or less.

  The saponification degree of the vinyl acetate component is preferably 80 to 100 mol%. From the viewpoint of obtaining a molded article excellent in gas barrier properties, it is more preferably 95 mol% or more, further preferably 98 mol% or more, and particularly preferably 99 mol% or more. If the saponification degree is less than 80 mol%, the barrier property, long run property, and moisture resistance may be deteriorated. In particular, in the case of producing an EVOH composition having excellent melt stability and long run property, the saponification degree of EVOH is preferably 99.7 mol% or more, and 99.8 mol% or more. More preferably, it is 99.9 mol% or more, more preferably 99.95 mol% or more.

  Further, when ethylene and vinyl acetate are copolymerized, other fatty acid vinyl esters (vinyl propionate, vinyl pivalate, etc.) can be used in combination. Moreover, EVOH can contain 0.0002-0.2 mol% of vinyl silane compounds as a copolymerization component. Here, examples of the vinylsilane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxy-ethoxy) silane, and γ-methacryloxypropylmethoxysilane. Of these, vinyltrimethoxysilane and vinyltriethoxysilane are preferably used.

  The EVOH production method will be specifically described below. The polymerization of ethylene and vinyl acetate is not limited to solution polymerization, and may be any of solution polymerization, suspension polymerization, emulsion polymerization, bulk polymerization, and may be either continuous or batch-type. The polymerization conditions in the case of polymerization are as follows.

Solvent: Alcohols are preferred, but other organic solvents (such as dimethyl sulfoxide) that can dissolve ethylene, vinyl acetate and ethylene-vinyl acetate copolymer can be used. As alcohols, methyl alcohol, ethyl alcohol, propyl alcohol, n-butyl alcohol, t-butyl alcohol and the like can be used, and methyl alcohol is particularly preferable.
Catalyst: 2,2-azobisisobutyronitrile, 2,2-azobis- (2,4-dimethylvaleronitrile), 2,2-azobis- (4-methyl-2,4-dimethylvaleronitrile), 2 , 2-azobis- (4-methoxy-2,4-dimethylvaleronitrile), 2,2-azobis- (2-cyclopropylpropionitrile) and the like azonitrile initiators, isobutyryl peroxide, cumylperoxyneo Organic peroxides such as decanoate, diisopropyl peroxycarbonate, di-n-propyl peroxydicarbonate, t-butyl peroxyneodecanoate, lauroyl peroxide, benzoyl peroxide, t-butyl hydroperoxide An initiator or the like can be used.
Temperature; 20-90 ° C, preferably 40 ° C-70 ° C.
Time (average residence time in case of continuous type); 2 to 15 hours, preferably 3 to 11 hours.
Polymerization rate: 10 to 90%, preferably 30 to 80%, relative to the charged vinyl ester.
Resin content in the solution after polymerization; 5 to 85%, preferably 20 to 70%.
Ethylene content in the copolymer; preferably 5 to 60 mol%, more preferably 15 to 55 mol%, optimally 20 to 50 mol%.

  In addition to ethylene and vinyl acetate, monomers that can be copolymerized with these, for example, α-olefins such as propylene, isobutylene, α-octene, α-dodecene; acrylic acid, methacrylic acid, crotonic acid, maleic acid, itacone Unsaturated acids such as acids or their anhydrides, salts, mono- or dialkyl esters, etc .; Nitriles such as acrylonitrile and methacrylonitrile; Amides such as acrylamide and methacrylamide; Ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfone An olefin sulfonic acid such as an acid or a salt thereof; alkyl vinyl ethers, vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride and the like can also be present in a small amount.

  After polymerization for a predetermined time, after reaching a predetermined polymerization rate, a polymerization inhibitor is added if necessary, and unreacted ethylene gas is removed by evaporation, and then unreacted vinyl acetate is driven off. As a method of driving off unreacted vinyl acetate from the ethylene-vinyl acetate copolymer solution from which ethylene has been removed by evaporation, for example, the copolymer solution is continuously supplied at a constant rate from the upper part of a tower packed with Raschig rings, A method in which an organic solvent vapor such as methanol is blown from the bottom of the tower, a mixed vapor of an organic solvent such as methanol and unreacted vinyl acetate is distilled from the top of the tower, and the copolymer solution from which the unreacted vinyl acetate has been removed is removed from the bottom of the tower Etc. are adopted.

An alkali catalyst is added to the copolymer solution from which unreacted vinyl acetate has been removed to saponify the vinyl acetate component in the copolymer. The saponification method can be either continuous or batch. As the alkali catalyst, sodium hydroxide, potassium hydroxide, alkali metal alcoholate or the like is used. Moreover, as a solvent used for saponification, methanol is preferable. For example, the saponification conditions are as follows.
The copolymer solution concentration: 10 to 50%.
Reaction temperature: 30-150 ° C.
Amount of catalyst used: 0.005 to 0.6 equivalent (per vinyl acetate component).
Time (in the case of continuous type, average residence time); 10 minutes to 6 hours.

In general, when saponification is performed continuously, methyl acetate produced by saponification can be removed more efficiently, so that a resin having a high saponification degree can be obtained with a smaller amount of catalyst than in the case of batch-wise. In the case of a continuous type, it is necessary to saponify at a higher temperature in order to prevent precipitation of EVOH produced by saponification. Therefore, it is preferable to set the reaction temperature and the catalyst amount within the following ranges in the continuous method.
Reaction temperature: 70-150 ° C.
Amount of catalyst used: 0.005 to 0.1 equivalent (per vinyl acetate component).

  The degree of saponification after the saponification reaction varies depending on the purpose, but is preferably 80 mol% or more, more preferably 95 mol% or more, still more preferably 98 mol% or more, particularly preferably 99 mol% or more of the vinyl acetate component. The degree of saponification can be arbitrarily adjusted according to the conditions.

  As described above, in the case of producing an EVOH composition having excellent melt stability and long run property, the saponification degree of EVOH is preferably 99.7 mol% or more, and 99.8 mol%. More preferably, it is more preferably 99.9 mol% or more, and particularly preferably 99.95 mol% or more. In order to obtain such EVOH, the saponification conditions are further reduced as follows. It is preferable to adjust as follows.

  As a method for obtaining EVOH having a high saponification degree of 99.9 mol% or more, a continuous method is preferable. As a method for obtaining a high saponification degree in a continuous manner, for example, a method of adding a catalyst from a plurality of locations in a saponification reaction tower, a method of increasing the amount of catalyst used, and a large amount of methanol blown from the lower part of the saponification reaction tower. The method of doing is mentioned. Moreover, as a method for obtaining EVOH having a high saponification degree of 99.9 mol% or more by batch method, for example, a method of adding a catalyst in a plurality of times, a method of increasing the amount of catalyst used, a saponification For example, a method of increasing the amount of methanol vapor or nitrogen gas blown into the reaction vessel may be used.

  The method for producing EVOH pellets from the obtained alcohol solution of EVOH after saponification is not particularly limited. Preferably, an alcohol solution of EVOH is precipitated in a strand form in a coagulation bath, and then the strands are cut to obtain water-containing pellets. In the precipitation, the alcohol solution may be concentrated to increase the EVOH concentration as compared with the saponification, or a part or all of methanol may be replaced with water, and the EVOH water / alcohol mixed solution or A water-containing composition of EVOH may be used. A water-containing pellet is obtained by extruding this into water or an alcohol aqueous solution containing a small amount of alcohol, and precipitating it into a strand shape, followed by cutting. Moreover, it can cut | disconnect with a fluid state, without making it precipitate in a strand form, and can also solidify in water and can manufacture a pellet.

  The water-containing pellets obtained as described above are porous, and the saponification catalyst residue can be easily removed by washing with water, and the subsequent addition of additives and drying operations are also easy. It is preferable that the moisture content of such a water-containing pellet is 10 to 80% by weight because of the above operational advantages. The water content is more preferably 20% by weight or more, and further preferably 30% by weight or more. Moreover, it is 70 weight% or less more suitably, More preferably, it is 60 weight% or less.

  The water-containing pellets thus obtained usually contain an alkali metal salt that is a saponification catalyst residue, for example, sodium acetate, which causes problems such as coloring, and thus is preferably removed by washing. Usually, the alkali metal salt content of the water-containing pellets before washing is about 100 to 10,000 μmol / g (per EVOH weight) in terms of alkali metal. The cleaning method is not particularly limited, but a method of cleaning with water is preferable. The water used as the cleaning liquid at this time may be an aqueous solution of an acid such as acetic acid in order to efficiently remove alkali metal ions. Moreover, it is also preferable to reduce the content of the saponification catalyst residue efficiently by using water washing and acid washing together.

  It is preferable to reduce the alkali metal content of the water-containing pellets after washing to 0-50 μmol / g (per EVOH weight) in terms of alkali metal. The upper limit of the alkali metal content is more preferably 40 μmol / g, still more preferably 30 μmol / g, and particularly preferably 20 μmol / g. Since the saponification catalyst residue is usually contained in the form of an alkali metal salt of acetic acid, the content of carboxylic acid radicals was reduced by sufficiently reducing the alkali metal content of the water-containing pellets after washing. It becomes easy to obtain an EVOH composition.

  The method for washing the water-containing pellets is not particularly limited, and either a batch type processing container or a continuous type processing container can be used. Especially, the method of supplying and processing a pellet continuously in a tower type container is suitable from a viewpoint of productivity.

  In the EVOH resin composition used in the present invention, EVOH is added to an aqueous solution containing at least one additive selected from the group consisting of an alkali metal salt (A) and a boron compound (B) and containing carbon dioxide gas. A method for producing an EVOH resin composition in which a resin is brought into contact is suitably employed. At this time, the aqueous solution in contact with the EVOH resin is an aqueous solution containing at least one additive selected from the group consisting of an alkali metal salt (A) and a boron compound (B) and containing carbon dioxide gas. .

  The amount of carbon dioxide gas contained in the aqueous solution is not particularly limited and can be appropriately adjusted. However, the amount of carbon dioxide gas present in the air is more than the amount that naturally dissolves carbon dioxide gas. It is necessary to let The concentration of carbon dioxide gas in the aqueous solution (total of free carbon dioxide and carbonic acid) is preferably 0.5 mmol / L or more, more preferably 2 mmol / L or more, and further preferably 10 mmol / L or more. . Moreover, in order to raise the solubility of a carbon dioxide gas, you may process on pressurization conditions of about 1.5-10 atmospheres.

  When a continuous processing vessel, particularly a tower type vessel, is used to continuously feed and process pellets, when the concentration of carbon dioxide in the aqueous solution is too high, bubbles are generated around the EVOH pellets. In some cases, the resin sedimentation may be adversely affected. Therefore, when such a continuous processing process is applied, it may be preferable that the carbon dioxide concentration in the aqueous solution is lower than the saturated carbon dioxide concentration. In this case, the carbon dioxide concentration is set to a value less than the saturated carbon dioxide concentration, preferably 0.95 times or less of the saturated carbon dioxide concentration, more preferably 0.9 times or less the saturated carbon dioxide concentration. The This concentration is determined by affecting the temperature and pressure of the treatment liquid. On the other hand, when a batch-type processing container is used, the above problem of sedimentation usually does not occur, but the upper limit value of the carbon dioxide gas concentration can be set in the same manner as in the continuous processing container.

  The aqueous solution preferably contains an alkali metal salt (A) from the viewpoint of securing interlayer adhesion and long run properties. The preferred range of the content of the alkali metal salt (A) is affected by the water content of the water-containing pellets, but generally it is preferably 0.05 to 40 mmol / L. A more preferable lower limit of the content of the alkali metal salt (A) in the aqueous solution is 0.1 mmol / L. A more preferred upper limit is 20 mmol / L. As will be described later, since the suitable content of the alkali metal salt (A) in the resin composition varies depending on the ethylene content of EVOH, the content of the alkali metal salt (A) in the aqueous solution corresponding to the content varies accordingly. It is preferable to adjust the amount.

  The cation species of the alkali metal salt (A) is not particularly limited. It is selected from lithium, sodium, potassium, rubidium and cesium salts, with sodium and potassium salts being preferred, and potassium being particularly preferred. By using the potassium salt, an EVOH resin composition excellent in both interlayer adhesion and long run properties can be obtained.

  The anion species of the alkali metal salt (A) is not particularly limited. Can be added as carbonate, bicarbonate, phosphate, hydrogen phosphate, hydroxide, carboxylate, etc. Among them, added as carbonate, bicarbonate, hydrogen phosphate and hydroxide It is preferable to do. Moreover, it is also preferable to add as a borate as shown below. However, in view of the purpose of the present invention to reduce the content of carboxylic acid radicals, it is better not to be a carboxylate.

  Moreover, it is preferable that the said aqueous solution contains a boron compound (B) from the point which can improve the long run property at the time of melt molding. When the concentration of the boron compound (B) in the aqueous solution is 0.1 to 50 mmol / L in terms of boron element, an appropriate amount of the boron compound (B) can be contained in the dry resin composition pellets. It is preferable. The lower limit value of the concentration of the boron compound (B) is more preferably 0.5 mmol / L or more, and further preferably 1 mmol / L or more. The upper limit is more preferably 40 mmol / L or less, and even more preferably 30 mmol / L or less. If it exceeds 50 mmol / L, the EVOH resin composition tends to gel, and the appearance of the molded product may be deteriorated.

  Examples of the boron compound (B) used for the preparation of the aqueous solution include, but are not limited to, boric acids, boric acid esters, borates, borohydrides, and the like. Specific examples of boric acids include orthoboric acid, metaboric acid, and tetraboric acid. Examples of boric acid esters include triethyl borate and trimethyl borate. Examples include alkali metal salts of acids, alkaline earth metal salts, and borax. Among these compounds, orthoboric acid (hereinafter sometimes simply referred to as boric acid) is preferable.

  Moreover, it is desirable for the said aqueous solution not to contain carboxylic acid or its salt (C) from the meaning of this invention. However, this does not exclude that the carboxylic acid or its salt (C) remaining in the EVOH resin dissolves into the aqueous solution and is contained as a result. Moreover, it does not exclude containing carboxylic acid or its salt (C) in the range which does not inhibit the effect of this invention.

  In order to balance the long run property and the color resistance at the time of melt molding, particularly the color resistance at the time of high temperature molding and the interlayer adhesion, the aqueous solution preferably contains a phosphoric acid compound (D). By containing an appropriate amount of the phosphoric acid compound (D), it is possible to suppress coloring of the molded product and generation of gels and blisters when the obtained EVOH resin composition is melt-molded. The upper limit of the concentration of the phosphoric acid compound (D) in the aqueous solution when adding the phosphoric acid compound (D) is preferably 10 mmol / L, more preferably 5 mmol / L in terms of phosphate radical. More preferably, it is 3.5 mmol / L, and most preferably 2.5 mmol / L. On the other hand, the lower limit value of the concentration of the phosphoric acid compound (D) in the aqueous solution when adding the phosphoric acid compound (D) is preferably 0.01 mmol / L, more preferably 0 in terms of phosphate radical. 0.03 mmol / L, more preferably 0.05 mmol / L, and most preferably 0.1 mmol / L.

  As the phosphoric acid compound (D) used for the preparation of the aqueous solution, an inorganic phosphoric acid compound is preferably used, and various acids such as phosphoric acid and phosphorous acid and salts thereof are exemplified. The phosphate may be contained in any form of primary phosphate, secondary phosphate, and tertiary phosphate, and its cationic species is not particularly limited, but alkali metal salts It is preferable that Among these, it is preferable to add the phosphoric acid compound (D) in the form of sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, or dipotassium hydrogen phosphate.

  The aqueous solution may contain an alkaline earth metal salt (E). However, since the alkaline earth metal salt tends to form a hardly soluble carbonate, it is not appropriate to add it in a large amount. Depending on the application, it may be possible to improve the long run property when the obtained EVOH resin composition is melt-molded by adding an appropriate amount. The addition of the alkaline earth metal salt (E) is optional, but the concentration of the alkaline earth metal salt (E) in the aqueous solution when added is in the range of 0 to 10 mmol / L in terms of alkaline earth metal. It is preferable that the alkaline earth metal salt (E) can be contained in the dry resin composition pellets. The upper limit is more preferably 5 mmol / L or less, and further preferably 3 mmol / L or less.

  The cationic species of the alkaline earth metal salt (E) is not particularly limited. Magnesium salts, calcium salts, barium salts, strontium salts and the like can be mentioned, and magnesium salts and calcium salts are preferred. The anionic species of the alkaline earth metal salt (E) is not particularly limited. Can be added as carbonate, bicarbonate, phosphate, hydrogen phosphate, hydroxide, carboxylate, etc. Among them, added as carbonate, bicarbonate, hydrogen phosphate and hydroxide It is preferable to do. Usually, the above alkaline earth metal salts are hardly soluble in water, but the solubility increases due to the presence of carbonic acid. However, in view of the purpose of the present invention to reduce the content of carboxylic acid radicals, it is better not to be a carboxylate.

  The pH of the aqueous solution containing the additive and carbon dioxide gas is preferably 3.5 to 6.5. By containing a certain amount or more of carbon dioxide gas, such an acidic aqueous solution can be obtained. The pH value is more preferably 3.8 or more, and further preferably 4 or more. Further, the pH value is more preferably 6.3 or less, further preferably 6.0 or less, and most preferably 5.8 or less.

  The method for preparing the aqueous solution containing the additive and carbon dioxide gas is not particularly limited. You may add at least 1 sort (s) of additives selected from the group which consists of an alkali metal salt (A) and a boron compound (B) in the aqueous solution which melt | dissolved the carbon dioxide gas previously. Conversely, carbon dioxide gas may be dissolved in an aqueous solution in which at least one additive selected from the group consisting of alkali metal salts (A) and boron compounds (B) is dissolved in advance. Alternatively, each aqueous solution may be prepared in advance and then mixed.

  A method of bringing the EVOH resin into contact with the aqueous solution is not particularly limited, but a method of immersing the EVOH resin in the aqueous solution is desirable. The shape of the EVOH resin when immersing the EVOH resin in the aqueous solution may be any shape such as powder, granular, spherical, cylindrical pellet, etc. For example, the water-containing EVOH pellet obtained as described above may be used. It is preferable to contact the aqueous solution. By immersing the pellet in the water-containing state in the aqueous solution, the alkali metal salt (A) or the boron compound (B) can be efficiently and uniformly contained in the EVOH resin pellet. The water content of the water-containing pellets before being immersed in the aqueous solution is preferably 10 to 80% by weight. The water content is more preferably 20% by weight or more, and further preferably 30% by weight or more. Moreover, it is 75 weight% or less more suitably, More preferably, it is 70 weight% or less.

  The temperature of the aqueous solution brought into contact with the EVOH resin is not particularly limited, but is preferably 10 to 90 ° C. If it is less than 10 degreeC, there exists a possibility that it may take time to make an alkali metal salt (A) or a boron compound (B) contain uniformly in EVOH resin pellet, and when it exceeds 90 degreeC, the saturation solubility of a carbon dioxide gas will fall. In addition, it may be difficult to contain a sufficient amount of carbon dioxide gas in the solution, and the pellets may be fused. The temperature of the aqueous solution is more preferably 20 ° C. or higher, and further preferably 30 ° C. or higher. Moreover, it is 85 degreeC or less more suitably, More preferably, it is 80 degreeC or less. When contacting at a high temperature of 70 ° C. or higher, the solubility of carbonic acid is reduced, and therefore, it is preferable that the contact is performed under a pressure of about 1.5 to 10 atm.

  The preferred range of time for contacting the EVOH resin with the aqueous solution varies depending on the form of the EVOH resin, but in the case of pellets of about 1 to 10 mm, it is preferably 1 hour or more, more preferably 2 hours or more. preferable.

  A method for bringing the EVOH resin into contact with the aqueous solution is not particularly limited. The EVOH resin can be brought into contact with water in advance, and the carbon dioxide gas and the additive can be dissolved in water later. However, the method in which the aqueous solution prepared by dissolving these in advance is brought into contact with the EVOH resin is used as an additive. A stable quality EVOH resin composition containing uniformly is obtained, which is preferable.

  As a method of bringing the EVOH resin into contact with the aqueous solution, either a batch method or a continuous method can be adopted. In the continuous method, for example, a method in which the EVOH resin is brought into contact with the continuously supplied aqueous solution while gradually moving the EVOH resin downward in a tower-shaped container is preferable.

  Also, a plurality of aqueous solutions may be prepared and contacted in a plurality of times. For example, after first contacting with an aqueous solution containing only the alkali metal salt (A) or boron compound (B), carbon dioxide is also contained in addition to the alkali metal salt (A) or boron compound (B). A method of contacting with an aqueous solution to be used can also be adopted.

  Furthermore, the EVOH resin is immersed in an aqueous solution containing carbon dioxide gas in addition to the alkali metal salt (A) or boron compound (B) and then brought into contact with the solution. It is also possible to employ a method in which (A), a boron compound (B), a phosphoric acid compound (D) or an alkaline earth metal salt (E) is brought into contact with an aqueous solution and melt-kneaded.

  The EVOH resin, preferably the EVOH resin pellet, is brought into contact with the aqueous solution, and then drained as necessary before being subjected to a drying step. The drying method is not particularly limited, and a hot air dryer or the like can be used, and drying may be performed while melt-kneading in an extruder with a vent. The dryer may be a fluid dryer or a stationary dryer, and may be used in combination. Among these, a method of drying by a fluidized drying method first and then drying by a stationary drying method is preferable. The drying temperature is not particularly limited, but usually a temperature of about 70 to 120 ° C. is adopted, and the temperature can be raised as the drying proceeds. The water content after drying is usually 1% by weight or less, preferably 0.5% by weight or less. The dried pellets thus obtained are used for the subsequent molding process.

  In the EVOH resin composition manufacturing method described above, since a resin composition containing almost no carboxylic acid radical is obtained, the carboxylic acid does not volatilize in this drying step, and the carboxylic acid is released to the periphery. We can provide a manufacturing method that is friendly to the surrounding environment.

  The EVOH resin composition preferably used in the present invention contains 0.1-20 μmol / g of an alkali metal salt (A) in terms of alkali metal, and is extracted by immersion in 95 ° C. water for 10 hours. EVOH containing 0 to 2 μmol / g of acid radical (C1) and 0 to 40 μmol / g of carboxylate radical (C2) extracted by immersion treatment in 0.05 N aqueous sodium hydroxide solution at 95 ° C. for 10 hours It is a resin composition.

  The EVOH resin composition is a resin composition that does not easily generate odor and is excellent in long run property during melt molding. The EVOH resin composition is preferably manufactured by the above-described manufacturing method, but is not limited to that manufactured by the method.

  This resin composition contains 0.1-20 micromol / g of alkali metal salt (A) in conversion of an alkali metal. By containing the alkali metal salt (A), interlayer adhesion, coloration resistance during melting, and long run properties are improved. When the content is less than 0.1 μmol / g, the interlayer adhesion, the coloration resistance at melting and the long run property are insufficient, and when it exceeds 20 μmol / g, the coloration resistance at melting becomes poor. In the range of 0.1 to 0.3 μmol / L, the coloration resistance and long run property at the time of melting are relatively good, but when used in a multilayer structure with other resins, the usual acid anhydride-modified adhesiveness The resin has insufficient adhesive strength. The lower limit of the content of the alkali metal salt (A) is more preferably 0.3 μmol / g or more, and more preferably 0.5 μmol / g or more. The upper limit of the content of the alkali metal salt (A) is preferably 15 μmol / g or less, more preferably 10 μmol / g or less, and particularly preferably 8 μmol / g or less.

At this time, it is preferable that the content of the alkali metal salt (A) and the ethylene content of EVOH satisfy the following formula (1).
0.95 × exp (0.039 × ET) −2 ≦ a ≦ 0.95 × exp (0.039 × ET) +2 (1)
here,
a is the content (μmol / g) of the alkali metal salt (A) in terms of alkali metal,
ET is the ethylene content of the ethylene-vinyl alcohol copolymer (mol%)
It is.

When there is more content of an alkali metal salt (A) than the range prescribed | regulated in the said (1) Formula, there exists a possibility that the hue of a resin composition may deteriorate. On the other hand, when it is less than the range specified in the above formula (1), the long run property and the adhesiveness may be deteriorated. It is more preferable to satisfy the following formula (1 ′), and it is more preferable to satisfy the following formula (1 ″).
0.95 × exp (0.039 × ET) −1.5 ≦ a ≦ 0.95 × exp (0.039 × ET) +1.5 (1 ')
0.95 × exp (0.039 × ET) −1 ≦ a ≦ 0.95 × exp (0.039 × ET) +1 (1 ")

  This resin composition contains 0 to 2 μmol / g of carboxylic acid radical (C1) extracted by immersion treatment in 95 ° C. water for 10 hours. Since it is assumed that most of the carboxylic acid and carboxylate contained in the EVOH resin composition are extracted by immersing in water at 95 ° C. for 10 hours, the carboxylic acid radical (C1) A numerical value almost corresponding to the total content of is shown. That is, this resin composition is a resin composition having a very low content of carboxylic acid and carboxylate. The content of the carboxylate group (C1) is preferably 1.5 μmol / g or less, more preferably 1 μmol / g or less, and further preferably 0.5 μmol / g.

  Moreover, this resin composition contains 0-40 micromol / g of carboxylic acid radicals (C2) extracted by immersion treatment in 0.05 normal sodium hydroxide aqueous solution at 95 ° C. for 10 hours. By immersing in an aqueous 0.05 N sodium hydroxide solution at 95 ° C. for 10 hours, not only most of the carboxylic acid and carboxylate contained in the EVOH resin composition are extracted, but also in the EVOH resin. In most of the unsaponified carboxylic acid ester groups remaining in the saponification reaction, the saponification reaction proceeds, and the carboxylic acid radical as the hydrolysis product is released and extracted. That is, this resin composition is a resin composition having a small total content of carboxylic acid, carboxylate, and carboxylic acid ester groups. The content of the carboxylate group (C2) is preferably 20 μmol / g or less, more preferably 10 μmol / g or less, further preferably 5 μmol / g or less, and optimally 2 μmol / g.

  At the time of melt-molding the EVOH resin composition, the temperature is usually 200 ° C. or higher, and many chemical reactions can proceed at that temperature. The carboxylic acid ester group contained in the EVOH resin may be hydrolyzed by reacting with water to liberate carboxylic acid, or may undergo transesterification with carboxylic acid or carboxylate. In addition, it is conceivable that carboxylic acid or carboxylate reacts with a hydroxyl group of EVOH to generate a carboxylic acid ester group or transesterifies with a carboxylic acid ester group. That is, in melt molding, particularly long-time melt molding, such a chemical reaction in the molten resin during heat melting cannot be ignored.

  The present resin composition is focused on this point, and with the total content of carboxylic acid, carboxylate salt and carboxylate ester that can be converted to each other, improvement of the melt stability of the resin and prevention of odor generation are achieved. It is something to try. The amount of carboxylic acid radical (C1) extracted by immersing in 95 ° C. water in a free form from the beginning for 10 hours is extremely small, including that which can be liberated under heating and melting conditions. When the amount of the carboxylic acid radical (C2) extracted by immersing in a 0.05 N aqueous sodium hydroxide solution for 10 hours is set to a certain value or less, a resin composition having an extremely long run property is obtained.

  Another EVOH resin composition preferably used in the present invention contains an alkali metal salt (A) in an amount of 0.1 to 20 μmol / g in terms of alkali metal, and is extracted by immersion in 95 ° C. water for 10 hours. The ethylene-vinyl alcohol copolymer resin composition contains 0 to 2 μmol / g of carboxylic acid radical (C1) and has a saponification degree of 99.7 to 100 mol%.

  This is a resin composition similar to the resin composition described above, but in place of the carboxylic acid radical (C2) extracted by immersion in a 0.05 N aqueous sodium hydroxide solution at 95 ° C. for 10 hours, The amount of the carboxylic acid ester group is expressed as a saponification value. When EVOH has a saponification degree of 99.7 mol% or more, it has excellent long-run properties during melt molding. The saponification degree is more preferably 99.8 mol% or more, further preferably 99.9 mol% or more, and particularly preferably 99.95 mol% or more.

  It is preferable that the EVOH resin composition used in the present invention further contains a boron compound (B) because the long run property during melt molding can be further improved. The effects of blending the boron compound (B) and the types thereof are as described in the description of the method for producing the EVOH resin composition. The content of the boron compound (B) is preferably 1 to 200 μmol / g in terms of boron element. It is more preferably 2 μmol / g or more, and further preferably 3 μmol / g or more. Moreover, it is more preferable that it is 150 micromol / g or less, and it is further more preferable that it is 100 micromol / g or less.

  Moreover, it is preferable that these resin compositions contain the phosphoric acid compound (D) in order to balance the long run property during melt molding, color resistance, particularly color resistance during high temperature molding, and interlayer adhesion. . The effects and types of the phosphoric acid compound (D) are as described in the description of the method for producing the EVOH resin composition. The upper limit of the content of the phosphoric acid compound (D) is preferably 5 μmol / g, more preferably 4 μmol / g, more preferably 3 μmol / g, and most preferably 1 in terms of phosphate radical. .5 μmol / g. When there are too many phosphate radicals, there is a possibility that the long run property is lowered. On the other hand, the lower limit of the content of the phosphate compound (D) is preferably 0.05 μmol / g, more preferably 0.1 μmol / g, and even more preferably 0.15 μmol / g in terms of phosphate radical. g, optimally 0.2 μmol / g.

  At this time, the content (a: μmol / g) of the alkali metal salt (A) in terms of alkali metal in the resin composition and the content (d: μmol) of the phosphate compound (D) in terms of phosphate radical. / G), the ratio (a / d) is preferably 2.4-50. By doing so, a resin composition having a good hue and long run property can be obtained. When the ratio (a / d) is less than 2.4, the long run property may be deteriorated. On the other hand, when the ratio (a / d) exceeds 50, the hue may be deteriorated, and the long run property may be adversely affected. The ratio (a / d) is more preferably 40 or less, and even more preferably 30 or less.

  These resin compositions may contain an alkaline earth metal salt (E). The effects and types of the alkaline earth metal salt (E) are as described in the description of the method for producing the EVOH resin composition. The content of the alkaline earth metal salt (E) is preferably 0 to 10 μmol / g in terms of alkaline earth metal. It is more preferably 5 μmol / g or less, and further preferably 3 μmol / g or less. In particular, when emphasizing the suppression of coloring during melt molding, the content of the alkaline earth metal salt (E) is more preferably 2 μmol / g or less, and further preferably 1 μmol / g or less. It is preferable that it is not substantially contained.

  A suitable melt flow rate (MFR) of the EVOH resin composition used in the present invention (measured at 190 ° C. under a load of 2160 g; provided that the melting point is around 190 ° C. or exceeds 190 ° C. It is measured at a plurality of temperatures, and in a semi-log graph, the reciprocal absolute temperature is plotted on the horizontal axis and the melt flow rate is plotted on the vertical axis (logarithm) and extrapolated to 190 ° C.) is preferably 0.1 to 200 g / 10 min. It is. The lower limit of MFR is more preferably 0.2 g / 10 min. More preferably, 0.5 g / 10 min. Above, optimally 1 g / 10 min. That's it. Further, the upper limit of MFR is more preferably 50 g / 10 min. Or more preferably 30 g / 10 min. And optimally 15 g / 10 min. It is as follows. When the melt flow rate is smaller than the above range, the inside of the extruder is in a high torque state at the time of molding, making extrusion difficult, and when larger than the range, the mechanical strength of the molded product is insufficient, which is preferable. Absent.

  The EVOH resin composition used in the present invention can be blended and melt-molded with EVOH having different degrees of polymerization, ethylene content and saponification degree. In addition, other plasticizers, lubricants, stabilizers, surfactants, colorants, UV absorbers, antistatic agents, desiccants, crosslinking agents, metal salts, fillers, reinforcing agents such as various fibers, etc. are added in appropriate amounts. It is also possible to do. Preferably, it is subjected to a melt molding process in the form of pellets.

  When the EVOH resin composition to be subjected to melt molding contains a phosphoric acid compound (D), the obtained molded product has a phosphoric acid compound (D) content in terms of phosphate radical (d: μmol / g) and the phosphorus element content (t: μmol / g) (d / t) is 0.4 or less, and ethylene-vinyl alcohol containing substantially no organophosphorus compound extractable with chloroform A melt-molded product made of a copolymer resin composition is preferred. Such a melt-molded article is preferably obtained by melt-molding the aforementioned EVOH resin composition, but is not limited thereto.

  Here, content (d) of a phosphoric acid compound (D) is a value calculated | required from the quantity of the phosphoric acid radical extracted, for example by immersing a melt-molded article in aqueous solution. That is, it indicates the amount of the phosphoric acid compound (D) that is contained in the melt-molded product as phosphoric acid or a salt thereof and can be extracted with an aqueous solution. On the other hand, the phosphorus element content (t) is, for example, a value obtained by performing an emission analysis on the amount of phosphorus element contained in an aqueous solution in which ash obtained by completely burning a melt-formed product is dissolved. That is, not only what is extracted by an extraction operation in an aqueous solution but also the total phosphorus element contained in the melt-formed product is quantified. Therefore, the ratio (d / t) being 0.4 or less means that more than half of the total phosphorus elements contained in the melt-molded product are contained in an unextractable form.

  Conventionally, in the case where the phosphoric acid compound (D) is contained in EVOH, almost the entire amount of the phosphoric acid compound (D) contained in the EVOH resin composition can be extracted. It was possible to extract the phosphate compound (D). Therefore, the ratio (d / t) was close to 1 even after melt molding. On the other hand, most of the EVOH resin composition suitably used in the present invention can be extracted as long as it is immersed in an aqueous solution to contain the phosphate compound (D) and dried. Regardless, extraction is impossible by heating in the molten state. Even when the temperature is lower than the melting point, the ratio (d / t) tends to decrease when heated for a long time at a relatively high temperature. Therefore, a reduction in the ratio (d / t) may be observed not only in a melt-molded product but also in a pellet that has been heat-dried for a long time.

  Although it is not always clear what chemical structure the phosphorus element contained in the melt-molded product exists, the phosphate compound (D) reacts with the hydroxyl group of EVOH to form a phosphate ester. It is estimated that Thus, it is estimated that extraction is impossible by being fixed to the molecular chain of EVOH. This time, it is thought that unprecedented characteristics were obtained by adopting an unprecedented manufacturing method such as immersing in an aqueous solution containing carbon dioxide gas instead of using carboxylic acids such as acetic acid. However, the method for producing a melt-formed product having a ratio (d / t) of 0.4 or less is not particularly limited.

  The melt-formed product having a ratio (d / t) of 0.4 or less thus obtained is excellent in long run properties. It is also conceivable that the phosphorus element presumed to be fixed to the EVOH molecular chain contributes to thermal stability. The ratio (d / t) is preferably 0.35 or less, more preferably 0.3 or less, even more preferably 0.25 or less, and optimally 0.2 or less.

  The preferred range of the phosphorus element content (t) at this time is the same as the preferred range of the content of the phosphoric acid compound (D) in the aforementioned EVOH resin composition. This is because the phosphorus element content (t) does not substantially change before and after melting and heating. It is preferably 5 μmol / g, more preferably 4 μmol / g, even more preferably 3 μmol / g, and most preferably 1.5 μmol / g. On the other hand, the lower limit of the phosphorus element content (t) is preferably 0.05 μmol / g, more preferably 0.1 μmol / g, and even more preferably 0.15 μmol / g. Is 0.2 μmol / g.

  In some applications, the EVOH resin composition may contain an organic phosphorus compound such as an antioxidant. In such a case, if the ratio (d / t) is 0.4 or less, it contains a substantial amount of a phosphorus compound that is not fixed to the EVOH molecular chain but cannot be extracted into water. However, it is not always excellent in long run performance. Therefore, in order to distinguish from such a resin composition, it is preferable that the melt-molded product does not substantially contain an organophosphorus compound that can be extracted with chloroform. Here, “not containing substantially” means, for example, less than 0.01 μmol / g.

  Moreover, about the kind and content of the alkali metal salt (A), the boron compound (B), the carboxylate radical (C1, C2), and the alkaline earth metal salt (E) in the melt-molded product, the EVOH resin composition described above is used. It is the same as the case of. The same applies to the type of EVOH used, the relationship between the content of alkali metal salt (A) and the ethylene content of EVOH, and the like. None of these values change substantially before and after melt molding.

  The melt-molded article of the present invention is not particularly limited as long as the EVOH resin composition is once melted and then molded. Not only molded products in various forms depending on the application, but also pellets obtained by melt-kneading and then extruding and cutting are included in the melt-formed product of the present invention. The melt-formed product of the present invention may be blended with EVOH having a different degree of polymerization, ethylene content, and degree of saponification. Also contains other plasticizers, lubricants, stabilizers, surfactants, colorants, UV absorbers, antistatic agents, desiccants, crosslinking agents, metal salts, fillers, reinforcing agents such as various fibers, etc. It is also possible.

  The present invention is a film or sheet comprising the above EVOH resin composition. Here, the film usually has a thickness of less than about 300 μm, and the sheet usually has a thickness of about 300 μm or more. As a method of forming a film or sheet, an extrusion method is preferable, and T-die extrusion or inflation extrusion is employed. The melting temperature varies depending on the melting point of EVOH and the like, but is preferably about 150 to 270 ° C. When a film or sheet is produced, melt molding is often performed for a long time, and when a conventional EVOH resin composition is used, there is a problem that gels and blisters are likely to occur in long run molding. By using the EVOH resin composition of the present invention, this problem is solved. In this respect, the benefit of adopting the configuration of the present invention is great.

  Further, the film or sheet of the present invention may be composed of a single layer of the EVOH resin composition, or composed of a multilayer structure having a layer of the EVOH resin composition and another resin layer. It doesn't matter. Since the EVOH resin composition used in the present invention is excellent in interlayer adhesion, a multilayer structure is preferable from this point. The layer structure of the multilayer structure is represented by E / T, T / E / T, E / Ad / T, T, where E is EVOH resin composition, Ad is adhesive resin, and T is other thermoplastic resin. Although / Ad / E / Ad / T etc. are mentioned, it is not limited to this. Each of the layers shown here may be a single layer or may be a multilayer according to circumstances.

  The method for producing the multilayer structure is not particularly limited. For example, a method of co-extrusion of an EVOH resin composition and another thermoplastic resin, a method of melt-extruding another thermoplastic resin on a film or sheet made of the EVOH resin composition, and conversely, another thermoplastic resin A method of melt-extrusion coating an EVOH resin composition on a film or sheet comprising, further, combining a film or sheet obtained from the EVOH resin composition and a film or sheet of another substrate with an organic titanium compound, an isocyanate compound, Examples include a method of laminating using a known adhesive such as a polyester compound. Of these production methods, the coextrusion method is preferred. A method of co-extrusion molding of the EVOH resin composition and the thermoplastic resin is not particularly limited, and a multi-manifold merging method T-die method, a feed block merging method T-die method, an inflation method, and the like are exemplified as suitable ones.

  Other thermoplastic resins used for laminating with the EVOH resin composition include linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer. Polymers, polypropylene, propylene-α-olefin copolymers (α-olefins having 4 to 20 carbon atoms), olefins such as polybutene and polypentene alone or copolymers thereof, polyesters such as polyethylene terephthalate, polyester elastomers, nylon- 6, Polyamide resin such as nylon-6, 6, polystyrene, polyvinyl chloride, polyvinylidene chloride, acrylic resin, vinyl ester resin, polyurethane elastomer, polycarbonate, chlorinated polyethylene, chlorinated polypropylene, etc. The Among these, polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyamide, polystyrene, and polyester are preferably used. In particular, in the case of a film, it is preferable to laminate with polyethylene, polypropylene or polyamide, and in the case of a sheet, it is preferable to laminate with polypropylene or polystyrene.

  When laminating the EVOH resin composition and another thermoplastic resin, an adhesive resin may be used. In this case, an adhesive resin made of a carboxylic acid-modified polyolefin is preferable. Here, the carboxylic acid-modified polyolefin is a modified olefinic polymer containing a carboxyl group obtained by chemically (for example, by addition reaction or graft reaction) bonding an ethylenically unsaturated carboxylic acid or its anhydride to an olefin polymer. Refers to coalescence. In addition, the olefin polymer is a polyethylene (low pressure, medium pressure, high pressure), a polyolefin such as linear low density polyethylene, polypropylene, boribten, or the like, a comonomer (vinyl ester, non-polymer) capable of copolymerizing the olefin and the olefin. Means a copolymer with a saturated carboxylic acid ester and the like, for example, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ethyl ester copolymer, and the like. Of these, linear low density polyethylene, ethylene-vinyl acetate copolymer (vinyl acetate content 5-55 wt%), ethylene-acrylic acid ethyl ester copolymer (acrylic acid ethyl ester content 8-35 wt. %), Linear low density polyethylene and ethylene-vinyl acetate copolymers are particularly preferred. Examples of the ethylenically unsaturated carboxylic acid or its anhydride include ethylenically unsaturated monocarboxylic acid, its ester, ethylenically unsaturated dicarboxylic acid, its mono or diester, and its anhydride. Among these, ethylenically unsaturated dicarboxylic acid Anhydrides are preferred. Specific examples include maleic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride, maleic acid monomethyl ester, maleic acid monoethyl ester, maleic acid diethyl ester, and fumaric acid monomethyl ester. Acid is preferred.

  The film or sheet obtained as described above can be used as it is, and can be used as a packaging film, a pouch or the like, but various molded products can be obtained by further secondary processing. Examples of the secondary processing method include a method of stretching the film or sheet in a uniaxial or biaxial direction, a method of rolling the film or sheet, or a method of thermoforming the film or sheet.

  Among these, the thermoforming method is preferable. Thermoforming as used in this invention means shape | molding in a metal mold | die shape, after heating and softening a film or a sheet | seat. As a molding method, vacuum or compressed air is used, and if necessary, a plug is further formed into a mold shape (straight method, drape method, air slip method, snapback method, plug assist method, etc.) or press molding. The method etc. are mentioned. Various molding conditions such as the molding temperature, the degree of vacuum, the pressure of compressed air, or the molding speed are appropriately set depending on the plug shape, the mold shape, or the properties of the raw material film or sheet. Cups and trays obtained by thermoforming in this way are suitably used as various containers, particularly food packaging containers.

The use of the film or sheet of the present invention or the secondary molded product thereof is not particularly limited. It can be used in a wide range of applications that make use of excellent gas barrier properties. Among them, the film or sheet of the present invention has a good appearance and suppresses the generation of odor, and is therefore suitably used as various food packaging containers.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this Example. Hereinafter, “%” and “parts” are based on weight unless otherwise specified. In addition, all the water used ion-exchange water.

(1) Determination of alkali metal salt (A) Dry EVOH pellets were pulverized by freeze pulverization. The obtained pulverized EVOH was sieved with a sieve having a nominal size of 1 mm (conforming to standard sieve standard JIS Z-8801). 10 g of EVOH powder and 50 mL of 0.01N hydrochloric acid aqueous solution that passed through the above sieve were put into a 100 mL conical flask with a stopper, and a cooling condenser was attached, followed by stirring and extraction at 95 ° C. for 10 hours. 2 mL of the obtained extract was diluted with 8 mL of ion exchange water. The diluted extract was quantitatively analyzed using an ion chromatography IC7000 manufactured by Yokogawa Electric Corporation to determine the amounts of Na and K ions. In the determination, calibration curves prepared using a sodium chloride aqueous solution and a potassium chloride aqueous solution were used. From the amount of Na and K ions thus obtained, the amount of alkali metal salt (A) contained in the dried EVOH pellets was obtained in terms of metal element.

Ion chromatography measurement conditions:
Column: ICS-C25 manufactured by Yokogawa Electric Corporation
Eluent: aqueous solution containing 5.0 mM tartaric acid and 1.0 mM 2,6-pyridinedicarboxylic acid Measurement temperature: 40 ° C.
Eluent flow rate: 1 mL / min.
Sample injection amount: 50 μL

(2) Quantification of carboxylic acid radical (C1) extracted by immersing in 95 ° C. water for 10 hours. Dry EVOH pellets were pulverized by freeze pulverization. The obtained pulverized EVOH was sieved with a sieve having a nominal size of 1 mm (conforming to standard sieve standard JIS Z-8801). 10 g of EVOH powder and 50 mL of ion-exchanged water that passed through the above sieve were put into a 100 mL Erlenmeyer flask with a stopper, attached with a cooling condenser, and stirred and extracted at 95 ° C. for 10 hours. 2 mL of the obtained extract was diluted with 8 mL of ion exchange water. The diluted extract was quantitatively analyzed using an ion chromatography IC7000 manufactured by Yokogawa Electric Corporation, and the amount of carboxylic acid (acetic acid) ions was quantified to obtain a carboxylic acid radical (C1). Note that a calibration curve prepared using an aqueous acetic acid solution was used for quantification.

Ion chromatography measurement conditions:
Column: SCS5-252 manufactured by Yokogawa Electric Corporation
Eluent: 0.1% phosphoric acid aqueous solution Measurement temperature: 40 ° C
Eluent flow rate: 1 mL / min.
Sample injection amount: 50 μL

(3) Quantification of Carboxylic Acid Root (C2) Extracted by Dipping Treatment in 0.05 N Sodium Hydroxide Aqueous Solution at 95 ° C. for 10 Hours Dry EVOH pellets were pulverized by freeze pulverization. The obtained pulverized EVOH was sieved with a sieve having a nominal size of 1 mm (conforming to standard sieve standard JIS Z-8801). 10 g of EVOH powder passing through the above sieve and 50 mL of 0.05 N sodium hydroxide aqueous solution were put into a 100 mL Erlenmeyer flask with a stopper, attached with a cooling condenser, and heated and extracted while stirring at 95 ° C. for 10 hours. 7 mL of ion-exchanged water was added to 2 mL of the obtained extract to dilute, and 1 mL of 0.1 N phosphoric acid aqueous solution was further added to prepare a sample solution for analysis. The amount of the carboxylate ion contained in the diluted extract is quantitatively analyzed using an ion chromatography IC7000 manufactured by Yokogawa Electric Corporation, the amount of the carboxylate (acetate) ion is quantified, and the carboxylate group ( C2) was obtained. In addition, for the determination, 7 mL of ion-exchanged water was added to 2 mL of a solution obtained by diluting acetic acid with 0.05 N aqueous sodium hydroxide, and 1 mL of 0.1 N aqueous phosphoric acid was added. A standard curve was used.

Ion chromatography measurement conditions:
Column: SCS5-252 manufactured by Yokogawa Electric Corporation
Eluent: 0.1% phosphoric acid aqueous solution Measurement temperature: 40 ° C
Eluent flow rate: 1 mL / min.
Sample injection amount: 50 μL

(4) Determination of boron compound (B) 50 mg of dry EVOH pellets as a sample were completely burned by an oxygen flask combustion method, and the resulting combustion ash was dissolved in 10 mL of a 1 mol / L nitric acid aqueous solution. Using the solution, the content of the boron compound (B) was obtained in terms of boron element by high-frequency plasma emission analysis (ICP emission analyzer IRIS AP manufactured by Jarrel Ash).

(5) Quantification of content (d) of phosphoric acid compound (D) In this example, the content (d1) of the phosphoric acid compound (D) in the pellets before melt molding and the single-layer film after melt molding The content (d2) of the phosphoric acid compound (D) was measured.

  When measuring pellets before melt molding, first, dried EVOH pellets were pulverized by freeze pulverization. The obtained pulverized EVOH was sieved with a sieve having a nominal size of 1 mm (conforming to standard sieve standard JIS Z-8801). 10 g of EVOH powder passed through the sieve and 50 mL of 0.01 N hydrochloric acid aqueous solution were put into a 100 mL conical flask with a stopper, attached with a cooling condenser, and stirred and extracted at 95 ° C. for 4 hours. The obtained extract was quantitatively analyzed using an ion chromatography IC7000 manufactured by Yokogawa Electric Corporation, and the amount of phosphate ions was quantified to obtain a phosphate radical amount (d1: μmol / g). For the determination, a calibration curve prepared using an aqueous sodium dihydrogen phosphate solution was used.

  When measuring a single layer film after melt molding, it was measured in the same manner as a sample in the form of a pellet except that 5 g of a strip of the film was used instead of 10 g of the EVOH powder. The amount was quantified to obtain a phosphate radical amount (d2: μmol / g).

Ion chromatography measurement conditions:
Column: ICS-A23 manufactured by Yokogawa Electric Corporation
Eluent: Aqueous solution containing 2.5 mM sodium carbonate and 1.0 mM sodium bicarbonate Measurement temperature: 40 ° C
Sample injection amount: 50 μL

(6) Phosphorus element content (t)
100 mg of the monolayer film after melt molding was completely burned by an oxygen flask combustion method, and the obtained combustion ash was dissolved in 10 mL of a 1 mol / L nitric acid aqueous solution. Using this solution, a phosphorus element content (t: μmol / g) was obtained by high-frequency plasma emission analysis (ICP emission analyzer “IRIS AP” manufactured by Jarrel Ash).

(7) Content of organophosphorus compound extractable with chloroform 100 g of a melt-molded monolayer film crushed to a size of 5 mm square or less is filled into a cylindrical filter paper, and 3000 ml of chloroform is put into a flask. Then, extraction was performed for 48 hours under reflux conditions using a Soxhlet-type extraction apparatus. Chloroform was removed from the extract with a rotary evaporator to obtain a residue. The obtained residue was completely burned by an oxygen flask combustion method, and the obtained combustion ash was dissolved in 10 mL of 1 mol / L nitric acid aqueous solution. Using this solution, a phosphorus element content was obtained by high-frequency plasma emission analysis (ICP emission analysis device “IRIS AP” manufactured by Jarrel Ash).

(8) Measurement of saponification degree (NMR method)
Dry EVOH pellets were ground by freeze grinding. The obtained pulverized EVOH was sieved with a sieve having a nominal size of 1 mm (conforming to standard sieve standard JIS Z-8801). 5 g of EVOH powder that passed through the above sieve was immersed in 100 g of ion-exchanged water, stirred at 85 ° C. for 4 hours, then drained and dried twice. Using the obtained powder EVOH after washing, NMR was measured under the following measurement conditions, and the degree of saponification was determined by the following analysis method.

Measurement conditions: Device name: JEOL Superconducting Nuclear Magnetic Resonance Device Lambda 500
Observation frequency: 500 MHz
Solvent: DMSO-d6
Polymer concentration: 4% by weight
Measurement temperature: 40 ° C and 95 ° C
Number of integrations: 600 times Pulse delay time: 3.836 seconds Sample rotation speed: 10-12 Hz
Pulse width (90 ° pulse): 6.75 μsec

・ Analysis method In the measurement at 40 ° C., a hydrogen peak in the water molecule is observed around 3.3 ppm, and the methine hydrogen peak of the vinyl alcohol unit of EVOH has a portion of 3.1 to 3.7 ppm. It overlapped. On the other hand, in the measurement at 95 ° C., the overlap generated at 40 ° C. is eliminated, but the hydrogen peak of the hydroxyl group of the vinyl alcohol unit of EVOH present in the vicinity of 4 to 4.5 ppm is methine of the vinyl alcohol unit of EVOH. It overlapped with a portion of 3.7 to 4 ppm of the hydrogen peak. That is, for the quantification of EVOH vinyl alcohol unit methine hydrogen (3.1-4 ppm), in order to avoid overlap with the hydrogen peak of water or hydroxyl group, about 3.1-3.7 ppm portion, The measurement data of ° C. was adopted, the measurement data of 40 ° C. was adopted for the portion of 3.7 to 4 ppm, and the total amount of the methine hydrogen was quantified as the total value thereof. It is known that the hydrogen peak of water or hydroxyl shifts to the high magnetic field side by increasing the measurement temperature.

Therefore, it analyzed using the measurement result of both 40 degreeC and 95 degreeC as follows. From the spectrum measured at 40 ° C., the integrated value (I ₁ ) of the chemical shift peak of 3.7 to 4 ppm and the integrated value (I ₂ ) of the chemical shift peak of 0.6 to 1.8 ppm are obtained. On the other hand, from the spectrum measured at 95 ° C., the integrated value (I ₃ ) of the chemical shift peak at 3.1 to 3.7 ppm, the integrated value (I ₄ ) of the chemical shift peak at 0.6 to 1.8 ppm, and The integrated value (I ₅ ) of the peak of chemical shift of 1.9 to 2.1 ppm is determined. Here, the peak of chemical shift of 0.6 to 1.8 ppm is mainly derived from methylene hydrogen, and the peak of chemical shift of 1.9 to 2.1 ppm is in unsaponified vinyl acetate units. It is derived from methyl hydrogen. The saponification degree was calculated from these integral values by the following formula.

(9) Intrinsic Viscosity 0.20 g of dry EVOH pellets to be used as a sample is precisely weighed and dissolved in 40 mL of hydrous phenol (water / phenol = 15/85 wt%) at 60 ° C. for 4 hours. Then, the viscosity was measured with an Ostwald viscometer (t0 = 90 seconds), and the intrinsic (extreme) viscosity [η] was determined by the following equation.
[Η] = (2 × (ηsp−lnηrel)) 1/2 / C (L / g)
ηsp = t / t0-1 (specific viscosity)
ηrel = t / t0 (relative viscosity)
C: EVOH concentration (g / L)
T0: Time for blank (hydrous phenol) to pass through viscometer t: Time for hydrous phenol solution in which sample is dissolved to pass viscometer

(10) Measurement of moisture content of water-containing EVOH pellets Using a HR73 halogen moisture content analyzer manufactured by METLER, the moisture content of EVOH pellets was measured under the conditions of a drying temperature of 180 ° C, a drying time of 20 minutes, and a sample amount of about 10 g.

(11) Measurement of carbon dioxide concentration A carbon dioxide sensor (CE-2041) was connected to a portable ion / pH meter (IM-22P) manufactured by Toa Denpa Kogyo Co., Ltd., and the carbon dioxide concentration in the solution was measured.

(12) Single-layer film formation test The obtained dried EVOH pellets were manufactured by Toyo Seiki Seisakusho 20 mm extruder D2020 (D (mm) = 20, L / D = 20, compression ratio = 2.0, screw: full A single-layer film was formed under the following conditions using a flight) to obtain a single-layer film.
Extrusion temperature: C1 / C2 / C3 / Die = 175/200/220/220 ° C.
Screw rotation speed: 40rpm
Discharge rate: 1.3 kg / hr
Take-up roll temperature: 80 ° C
Take-up roll speed: 3.1 m / min.
Film thickness: 20 μm

(12-a) Color resistance The single-layer film produced by the above method was wound around a paper tube, and the degree of color of the film end face was determined with the naked eye as follows.
Judgment: Standard A: No coloring B: Slightly yellow C: Yellowing

(12-b) 72 hr-long run property The film 72 hours after the start of monolayer film formation was sampled, and gel-like irregularities (those of about 100 μm or more that can be confirmed with the naked eye) in the film were counted.
The number of bumps was converted to the number per 1.0 m ² and judged as follows.
Determination: Standard A: Less than 20 B: 20 or more and less than 40 C: 40 or more and less than 60 D: 60 or more

(12-c) 120 hr-long-run property Films 120 hours after the start of monolayer film formation were sampled, and gel-like irregularities (those of about 100 μm or more that can be confirmed with the naked eye) in the film were counted.
The number of bumps was converted to the number per 1.0 m ² and judged as follows.
Determination: Standard A: Less than 20 B: 20 or more and less than 40 C: 40 or more and less than 60 D: 60 or more

(13) Evaluation of high-temperature colorability 5 g of the obtained dried EVOH pellets were heated and melted at 250 ° C. for 2 minutes using a heat compression press device to produce a disk-like sample having a thickness of 2 mm, and the hue was visually evaluated as follows. did.
Judgment: Criteria A: Almost no coloration.
B: Slightly yellowed.
C: Yellowish.

(14) Odor test 10 g of the obtained dry EVOH pellets and 10 mL of ion-exchanged water were put into a 100 mL glass screw tube, sealed and sealed. Then, after putting in 90 degreeC safe vent dryer (dryer) and heat-extracting for 15 hours, it stood at room temperature for 30 minutes and cooled the said screw pipe | tube. After cooling, the lid of the screw tube was opened, and the odor of the resulting extract was evaluated as follows by using five monitors. The evaluation was as follows.
Judgment: Criteria A: No odor is felt.
B: A slight odor is felt.
C: Odor is felt.

(15) Adhesive strength test Using the obtained dry EVOH pellets, linear low-density polyethylene (LLDPE; manufactured by Mitsui Chemicals, Ultzex 2022L) and adhesive resin (Tie; manufactured by SUMIKA. ATOCHEM Co. Ltd, Bondine TX8030) A multilayer film of 3 types and 5 layers (LLDPE / Tie / EVOH / Tie / LLDPE = 50 μ / 10 μ / 10 μ / 10 μ / 50 μ) was obtained by the following method.
Extruder and T-die specifications used in this test are as follows.
Extruder:
EVOH 20φ Extruder Lab Model ME Type CO-EXT (Toyo Seiki)
25φ extruder for Tie P25-18AC (Osaka Seiki)
32φ extruder for LLDPE GF-32-A (Plastic Engineering Laboratory)
EVOH extrusion temperature:
C1 / C2 / C3 / die = 175/210/220/220 ° C.
Tie extrusion temperature:
C1 / C2 / C3 / die = 100/160/220/220 ° C.
LLDPE extrusion temperature:
C1 / C2 / C3 / die = 150/200/210/220 ° C.
T-die: 300mm width coat hanger die (Plastic Engineering Laboratory)

(15-a) Adhesive strength immediately after film formation Immediately after multilayer film formation, the obtained multilayer film was cut out to 150 mm in the MD direction and 10 mm in the TD direction, and immediately after that, by autograph (manufactured by Shimadzu Corporation, DCS-50M) T-type peel strength measurement was performed. In the measurement, the interlayer adhesive strength between Tie and EVOH on the cooling roll side of the multilayer film was measured.

(15-b) Adhesive strength after one week from film formation The above-prepared sample consisting of a multilayer film having a length of 150 mm and a width of 10 mm was left in a constant temperature and humidity chamber at 23 ° C.-50% RH for one week. Using the sample, T-type peel strength measurement was performed in a constant temperature and humidity chamber of 23 ° C.-50% RH by an autograph (manufactured by Shimadzu Corporation, DCS-50M). In the measurement, the interlayer adhesive strength between Tie and EVOH on the cooling roll side of the multilayer film was measured.

Example 1
50 kg of a 45% methanol solution of ethylene-vinyl acetate copolymer having an ethylene content of 32 mol% and 129 kg of methanol were charged into a 470 L saponification reactor, and nitrogen gas was blown into the reactor while the internal temperature was set to 60 ° C. did. Thereto, 29 L (concentration: 80 g / L) of methanol solution of sodium hydroxide is added to start the saponification reaction. During the saponification reaction, methyl acetate generated as a by-product in the reaction system is continuously introduced into the reactor together with methanol in the reaction system in order to drive out the reaction system in order to increase the reaction efficiency. Nitrogen gas was continuously blown. The expelling speed was about 20 kg / hr in total of methyl acetate and methanol, and this was condensed and recovered using a cooling condenser. Two hours after the start of the reaction, 29 L of a methanol solution of sodium hydroxide (concentration: 80 g / L) was further added to drive the saponification reaction. Six hours after the start of the reaction, 6.8 kg of acetic acid and 56 L of water were added to neutralize the reaction solution to stop the reaction.

  The neutralized reaction solution was transferred from the reactor to a drum can and allowed to stand at room temperature for 16 hours to be cooled and solidified into a cake. Thereafter, the cake-like resin was drained using a centrifuge (manufactured by Kokusan Centrifuge Co., Ltd., H-130, rotation speed: 1200 rpm). Next, the step of decanting while continuously supplying ion-exchanged water from above to the center of the centrifuge and washing the resin with water was performed for 10 hours. The conductivity of the cleaning solution 10 hours after the start of cleaning was 30 μS / cm (measured with CM-30ET manufactured by Toa Denpa Kogyo).

  The granular EVOH thus obtained was dried at 60 ° C. for 48 hours using a dryer. 20 kg of dried granular EVOH was dissolved in 43 L of a water / methanol mixed solution (weight ratio: water / methanol = 4/6) at 80 ° C. for 12 hours with stirring. Next, the stirring was stopped and the temperature of the dissolution tank was lowered to 65 ° C. and left for 5 hours to degas the EVOH water / methanol solution. And it extrudes in a 5 degreeC water / methanol mixed solution (weight ratio: water / methanol = 9/1) from the metal plate which has a circular opening part with a diameter of 3.5 mm, precipitates in strand shape, and cuts. To obtain pellets having a diameter of about 4 mm and a length of about 5 mm.

  2.4 kg of the hydrous pellets thus obtained and 24 L of ion-exchanged water were placed in a plastic container having a height of 400 mm and an open diameter of 370 mm, washed with stirring at 25 ° C. for 2 hours, and then drained. Repeated twice. Next, an operation of adding 24 L of 1 g / L acetic acid aqueous solution to 2.4 kg of water-containing pellets, washing the mixture with stirring at 25 ° C. for 2 hours, and then removing the liquid was repeated twice. Further, 24 L of ion exchange water was added to 2.4 kg of the water-containing pellets, and the operation of washing with stirring at 25 ° C. for 2 hours and then draining was repeated 6 times. As a result of measuring the conductivity of the cleaning liquid after the sixth cleaning with CM-30ET manufactured by Toa Denpa Kogyo, the conductivity of the cleaning liquid was 3 μS / cm. The water content of the obtained EVOH pellets was 50% by weight.

  The thus-obtained EVOH after washing (ethylene content 32 mol%, saponification degree 99.98 mol% or more (calculated by NMR method), intrinsic viscosity 0.085 L / g) 2.4 kg hydrous pellets and concentration 0 A 36 g / L boric acid aqueous solution (5.1 L) was placed in a plastic container having a height of 300 mm and an opening diameter of 280 mm, immersed at 25 ° C. for 10 hours, and drained after immersion.

  Next, 5.1 L of ion-exchanged water was placed in a plastic container having a height of 300 mm and an opening diameter of 280 mm. A silicon tube (inner diameter 7 mm, outer diameter 10 mm) was put into the ion-exchanged water in the container, and 0.5 L, 1 L / min. Bubbling at a speed of carbon dioxide was blown. Carbon dioxide was supplied using a carbon dioxide cylinder (liquefied carbon dioxide 30 kg manufactured by Nippon Carbon Co., Ltd.) and a flow meter (Model RK-1600R manufactured by KOFLOC). 0.51 g of boric acid and 0.56 g of sodium carbonate were dissolved in the water into which the carbon dioxide gas was blown, and further, 1 L / min. Carbon dioxide was continuously blown at a speed of. The boric acid content of the treatment solution was 0.10 g / L, and the sodium carbonate content was 0.11 g / L. Moreover, when the pH of the said processing liquid after blowing in carbon dioxide gas for 1 hour was measured using the pH meter (Metler MA235), the pH of the said processing liquid was 5.1.

  Next, the blowing speed is 1 L / min. Then, 2.4 kg of the above water-containing pellets were added to the treatment liquid while blowing carbon dioxide gas, and immersed and stirred at 25 ° C. for 6 hours. Further, when the pH of the treatment liquid was measured every hour from the start of the treatment to the end of the treatment, the pH of the treatment liquid remained at 5.1 at any measurement and did not vary. It was 20 mmol / L when the carbon dioxide gas density | concentration in a process liquid was analyzed. After being immersed in the treatment solution for 6 hours and stirred, the obtained pellets were immediately drained and dried with hot air at 80 ° C. for 3 hours and subsequently at 107 ° C. for 24 hours to obtain dried EVOH pellets (water content) 0.2% by weight) was obtained.

  The alkali metal salt (A) in the obtained dried EVOH pellets was sodium, and the content of the alkali metal salt (A) was 3.13 μmol / g in terms of metal element. The content of the boron compound (B) in the obtained dry EVOH pellets was 160 ppm (15 μmol / g) in terms of boron element. The amount of carboxylic acid radical (C1) extracted by immersing the dried EVOH pellets in 95 ° C. pure water for 10 hours is 0 ppm (0 μmol / g), and 0.05 normal sodium hydroxide at 95 ° C. The amount of carboxylic acid (acetic acid) root (C2) extracted by immersion in an aqueous solution for 10 hours was 35 ppm (0.6 μmol / g). The MFR of the dried EVOH pellet is 1.6 g / 10 min. (Under 190 ° C. and 2160 g load).

  Using the obtained dry EVOH pellets, a single-layer film was prepared according to the above-described method, and a test for resistance to coloring and long run was performed. The evaluation results of the EVOH coloring resistance, 72-hour long run property, and 120-hour long run property of this example were all A.

  When the high temperature coloring property evaluation test was done according to the above-mentioned method using the obtained dry EVOH pellet, evaluation was B determination. Moreover, when the odor test was done according to the above-mentioned method using the obtained dry EVOH pellet, all five monitors did not feel odor, and evaluation was A determination.

  Moreover, when the adhesive strength test was performed according to the above-mentioned method using the obtained dry EVOH pellets, the adhesive strength immediately after film formation was 550 g / 15 mm, and the adhesive strength after one week from film formation was 800 g / It was 15 mm, and good adhesive strength was obtained in all cases.

Examples 2-6
Dry EVOH pellets in the same manner as in Example 1 except that the composition of the carbon dioxide-containing treatment liquid in which the hydrous EVOH pellets are immersed in the boric acid aqueous solution is changed as shown in Table 1. Was prepared and evaluated in the same manner as in Example 1. Table 2 shows the composition of the dry EVOH resin composition, and Table 3 shows the evaluation results.

Example 7
50 kg of a 45% methanol solution of ethylene-vinyl acetate copolymer having an ethylene content of 32 mol% and 129 kg of methanol were charged into a 470 L saponification reactor, and nitrogen gas was blown into the reactor while the internal temperature was set to 60 ° C. did. Thereto, 29 L (concentration: 80 g / L) of methanol solution of sodium hydroxide is added to start the saponification reaction. During the saponification reaction, methyl acetate generated as a by-product in the reaction system is continuously introduced into the reactor together with methanol in the reaction system in order to drive out the reaction system in order to increase the reaction efficiency. Nitrogen gas was continuously blown. The expelling speed was about 20 kg / hr in total of methyl acetate and methanol, and this was condensed and recovered using a cooling condenser. Two hours after the start of the reaction, 29 L of a methanol solution of sodium hydroxide (concentration: 80 g / L) was further added to drive the saponification reaction. Six hours after the start of the reaction, 6.8 kg of acetic acid and 56 L of water were added to neutralize the reaction solution to stop the reaction.

  The neutralized reaction solution was transferred from the reactor to a drum can and allowed to stand at room temperature for 16 hours to be cooled and solidified into a cake. Thereafter, the cake-like resin was drained using a centrifuge (manufactured by Kokusan Centrifuge Co., Ltd., H-130, rotation speed: 1200 rpm). Next, the step of decanting while continuously supplying ion-exchanged water from above to the center of the centrifuge and washing the resin with water was performed for 10 hours. The conductivity of the cleaning solution 10 hours after the start of cleaning was 30 μS / cm (measured with CM-30ET manufactured by Toa Denpa Kogyo).

  The granular EVOH thus obtained was dried at 60 ° C. for 48 hours using a dryer. 20 kg of dried granular EVOH was dissolved in 43 L of a water / methanol mixed solution (weight ratio: water / methanol = 4/6) at 80 ° C. for 12 hours with stirring. Next, the stirring was stopped and the temperature of the dissolution tank was lowered to 65 ° C. and left for 5 hours to degas the EVOH water / methanol solution. And it extrudes in a 5 degreeC water / methanol mixed solution (weight ratio: water / methanol = 9/1) from the metal plate which has a circular opening part with a diameter of 3.5 mm, precipitates in strand shape, and cuts. To obtain pellets having a diameter of about 4 mm and a length of about 5 mm.

  2.4 kg of the hydrous pellets thus obtained and 24 L of ion-exchanged water were placed in a plastic container having a height of 400 mm and an open diameter of 370 mm, washed with stirring at 25 ° C. for 2 hours, and then drained. Repeated twice. Next, an operation of adding 24 L of 1 g / L acetic acid aqueous solution to 2.4 kg of water-containing pellets, washing the mixture with stirring at 25 ° C. for 2 hours, and then removing the liquid was repeated twice. Further, 24 L of ion exchange water was added to 2.4 kg of the water-containing pellets, and the operation of washing with stirring at 25 ° C. for 2 hours and then draining was repeated 6 times. As a result of measuring the conductivity of the cleaning liquid after the sixth cleaning with CM-30ET manufactured by Toa Denpa Kogyo, the conductivity of the cleaning liquid was 3 μS / cm. The water content of the obtained EVOH pellets was 50% by weight.

  The thus-obtained EVOH after washing (ethylene content 32 mol%, saponification degree 99.98 mol% or more (calculated by NMR method), intrinsic viscosity 0.085 L / g) 2.4 kg hydrous pellets and concentration 0 A 36 g / L boric acid aqueous solution (5.1 L) was placed in a plastic container having a height of 300 mm and an opening diameter of 280 mm, immersed at 25 ° C. for 10 hours, and drained after immersion.

  Next, 24L of ion-exchanged water was placed in a plastic container having a height of 400 mm and an open diameter of 370 mm. A silicon tube (inner diameter: 7 mm, outer diameter: 10 mm) was put into the ion-exchanged water in the container (using five of the above-mentioned silicon tubes), and 2 L, 5 L / min. Bubbling at a speed of carbon dioxide was blown. Carbon dioxide was supplied using a carbon dioxide cylinder (liquefied carbon dioxide 30 kg manufactured by Nippon Carbon Co., Ltd.) and a flow meter (Model RK-1600R manufactured by KOFLOC). 1.68 g of boric acid, 6.48 g of dipotassium monohydrogen phosphate, and 1.20 g of phosphoric acid are dissolved in the water into which the carbon dioxide gas is blown, and further, 5 L / min. Carbon dioxide was continuously blown at a speed of. The treatment liquid had a boric acid content of 0.07 g / L, a monopotassium monohydrogen phosphate content of 0.27 g / L, and a phosphoric acid content of 0.05 g / L. Moreover, when the pH of the said processing liquid after blowing in carbon dioxide gas for 1 hour was measured using the pH meter (Metler MA235), the pH of the said processing liquid was 4.9.

  Next, the blowing speed is 5 L / min. Then, 2.4 kg of the above water-containing pellets were added to the treatment liquid while blowing carbon dioxide gas, and immersed and stirred at 25 ° C. for 6 hours. Further, when the pH of the treatment liquid was measured every hour from the start of the treatment to the end of the treatment, the pH of the treatment liquid remained at 4.9 at any measurement and did not change. As a result of analyzing the carbon dioxide gas concentration in the treatment liquid, it was 20 mmol / L. After being immersed in the treatment solution for 6 hours and stirred, the obtained pellets were immediately drained and dried with hot air at 80 ° C. for 3 hours and subsequently at 107 ° C. for 24 hours to obtain dried EVOH pellets (water content) 0.2% by weight) was obtained.

  The alkali metal salt (A) in the obtained dried EVOH pellets was potassium, and the content of the alkali metal salt (A) was 3.40 μmol / g in terms of metal element. The content (d1) of the phosphate compound (D) was 1.2 μmol / g in terms of phosphate radical. The content of the boron compound (B) in the obtained dry EVOH pellets was 143 ppm (13 μmol / g) in terms of boron element. The amount of carboxylic acid radical (C1) extracted by immersing the dried EVOH pellets in 95 ° C. pure water for 10 hours is 0 ppm (0 μmol / g), and 0.05 normal sodium hydroxide at 95 ° C. The amount of carboxylic acid (acetic acid) root (C2) extracted by immersion in an aqueous solution for 10 hours was 36 ppm (0.6 μmol / g). The MFR of the dried EVOH pellet is 1.6 g / 10 min. (Under 190 ° C. and 2160 g load).

  Using the obtained dry EVOH pellets, a single-layer film was prepared according to the above-described method, and a test for resistance to coloring and long run was performed. The evaluation results of the EVOH coloring resistance, 72-hour long run property, and 120-hour long run property of this example were all A. Moreover, content (d2) of the phosphoric acid compound (D) of a single layer film was 0.10 micromol / g in conversion of the phosphate radical, and phosphorus element content (t) was 1.2 micromol / g. The content of the organophosphorus compound that can be extracted with chloroform was less than 0.01 μmol / g.

  When the obtained high-temperature colorability evaluation test was performed according to the above-described method using the obtained dry EVOH pellets, the evaluation was A determination. Moreover, when the odor test was done according to the above-mentioned method using the obtained dry EVOH pellet, all five monitors did not feel odor, and evaluation was A determination.

  Moreover, when the adhesive strength test was performed according to the above-mentioned method using the obtained dry EVOH pellets, the adhesive strength immediately after film formation was 760 g / 15 mm, and the adhesive strength after one week from film formation was 900 g / It was 15 mm, and good adhesive strength was obtained in all cases.

Thermoforming multilayer films:
The dry EVOH pellets obtained as described above were used as a resin composition layer, linear low density polyethylene (LLDPE) {MFR = 2.1 g / 10 min (210 ° C., 2160 g load), “Wult Zex 3520L "} as a heat seal layer, maleic anhydride-modified polyethylene {MFR = 3.3 g / 10 min (210 ° C, 2160 g load), Mitsui Petrochemical's" Admer SF600 "} as an adhesive (AD) layer, Further, nylon 6 {MFR = 7.2 g / 10 min (230 ° C., 2160 g load), “UBE nylon 1022B” manufactured by Ube Industries, Ltd.] is a polyamide resin (PA) layer, and a co-extruder equipped with a T-die 4 types and 5 layers (PA / AD / resin composition layer / AD / LLDPE = 20 μm / 5 μm / 20 μm / 5 μm / 80 μm) and the total thickness is 130 A film for thermoforming of μm was obtained.

The film for thermoforming thus obtained was heated for 1.5 seconds at a heater plate temperature of 100 ° C. with a thermoforming machine (R530 manufactured by Mulchback Co., Ltd.) to a film temperature of about 85 ° C. It was molded using compressed air (atmospheric pressure 5 kgf / cm ² ) in a rectangular parallelepiped shape of 130 mm, width: 110 mm, and depth: 50 mm, to obtain a thermoformed container having a good appearance that was shaped according to the mold shape.

Multi-layer sheet thermoforming:
The dry EVOH pellets obtained as described above were used as the resin composition layer, and random copolymer polypropylene {Grand polymer “F226D”, MFR = 6 g / 10 min (230 ° C., 2160 g load)} was used as the inner and outer layers (PP layer). ) And a maleic anhydride-modified polypropylene {Admir QF500, manufactured by Mitsui Petrochemical Co., Ltd., MFR = 5.3 g / 10 min (230 ° C., 2160 g load)} as an adhesive layer (AD) layer, Was used to obtain a thermoforming sheet having a total thickness of 1000 μm with three types and five layers (PP / AD / resin composition / AD / PP = 400 μm / 50 μm / 100 μm / 50 μm / 400 μm).

The sheet thus obtained was thermoformed into a cup shape (die shape 70φ × 70 mm) with a thermoforming machine (manufactured by Asano Manufacturing Co., Ltd.) (pressure: 5 kg / cm ² , plug: 45φ ×). 65 mm, syntax foam, plug temperature: 150 ° C., mold temperature: 70 ° C. was used), and a cup with good appearance that was shaped according to the mold shape was obtained.

Example 8
50 kg of a 45% methanol solution of ethylene-vinyl acetate copolymer having an ethylene content of 44 mol% and 129 kg of methanol were charged into a 470 L saponification reactor, and the internal temperature was set to 60 ° C. while blowing nitrogen gas into the reactor. did. Thereto, 29 L (concentration: 80 g / L) of methanol solution of sodium hydroxide is added to start the saponification reaction. During the saponification reaction, methyl acetate generated as a by-product in the reaction system is continuously introduced into the reactor together with methanol in the reaction system in order to drive out the reaction system in order to increase the reaction efficiency. Nitrogen gas was continuously blown. The expelling speed was about 20 kg / hr in total of methyl acetate and methanol, and this was condensed and recovered using a cooling condenser. Two hours after the start of the reaction, 29 L of a methanol solution of sodium hydroxide (concentration: 80 g / L) was further added to drive the saponification reaction. Six hours after the start of the reaction, 6.8 kg of acetic acid and 45 L of water were added to neutralize the reaction solution to stop the reaction.

  The neutralized reaction solution was transferred from the reactor to a drum can and allowed to stand at room temperature for 16 hours to be cooled and solidified into a cake. Thereafter, the cake-like resin was drained using a centrifuge (manufactured by Kokusan Centrifuge Co., Ltd., H-130, rotation speed: 1200 rpm). Next, the step of decanting while continuously supplying ion-exchanged water from above to the center of the centrifuge and washing the resin with water was performed for 10 hours. The conductivity of the cleaning solution 10 hours after the start of cleaning was 30 μS / cm (measured with CM-30ET manufactured by Toa Denpa Kogyo).

  The granular EVOH thus obtained was dried at 60 ° C. for 48 hours using a dryer. 20 kg of dried granular EVOH was dissolved in 48 L of a water / methanol mixed solution (weight ratio: water / methanol = 2/8) at 80 ° C. for 12 hours with stirring. Next, the stirring was stopped and the temperature of the dissolution tank was lowered to 65 ° C. and left for 5 hours to degas the EVOH water / methanol solution. And it extrudes in a 5 degreeC water / methanol mixed solution (weight ratio: water / methanol = 9/1) from the metal plate which has a circular opening part with a diameter of 3.5 mm, precipitates in strand shape, and cuts. To obtain pellets having a diameter of about 4 mm and a length of about 5 mm.

  2.4 kg of the hydrous pellets thus obtained and 24 L of ion-exchanged water were placed in a plastic container having a height of 400 mm and an open diameter of 370 mm, washed with stirring at 25 ° C. for 2 hours, and then drained. Repeated twice. Next, an operation of adding 24 L of 1 g / L acetic acid aqueous solution to 2.4 kg of water-containing pellets, washing the mixture with stirring at 25 ° C. for 2 hours, and then removing the liquid was repeated twice. Further, 24 L of ion exchange water was added to 2.4 kg of the water-containing pellets, and the operation of washing with stirring at 25 ° C. for 2 hours and then draining was repeated 6 times. As a result of measuring the conductivity of the cleaning liquid after the sixth cleaning with CM-30ET manufactured by Toa Denpa Kogyo, the conductivity of the cleaning liquid was 3 μS / cm. The water content of the obtained EVOH pellets was 50% by weight.

  The thus-obtained EVOH after washing (ethylene content 44 mol%, saponification degree 99.98 mol% or more (calculated by NMR method), inherent viscosity 0.088 L / g) 2.4 kg hydrous pellets and concentration 0 A 51 g / L boric acid aqueous solution (5.1 L) was placed in a plastic container having a height of 300 mm and an opening diameter of 280 mm, immersed at 25 ° C. for 10 hours, and then drained.

  Next, 24L of ion-exchanged water was placed in a plastic container having a height of 400 mm and an open diameter of 370 mm. A silicon tube (inner diameter: 7 mm, outer diameter: 10 mm) was put into the ion-exchanged water in the container (using five of the above-mentioned silicon tubes), and 2 L, 5 L / min. Bubbling at a speed of carbon dioxide was blown. Carbon dioxide was supplied using a carbon dioxide cylinder (liquefied carbon dioxide 30 kg manufactured by Nippon Carbon Co., Ltd.) and a flow meter (Model RK-1600R manufactured by KOFLOC). 2.88 g of boric acid, 4.08 g of potassium hydrogen carbonate, and 6.17 g of potassium dihydrogen phosphate are dissolved in the water into which the carbon dioxide gas has been blown, and further, 5 L / min. Carbon dioxide was continuously blown at a speed of. The treatment solution had a boric acid content of 0.12 g / L, a potassium hydrogen carbonate content of 0.17 g / L, and a potassium dihydrogen phosphate of 0.257 g / L. Moreover, when the pH of the said processing liquid after blowing in carbon dioxide gas for 1 hour was measured using the pH meter (Metler MA235), the pH of the said processing liquid was 5.1.

  Next, the blowing speed is 5 L / min. Then, 2.4 kg of the above water-containing pellets were added to the treatment liquid while blowing carbon dioxide gas, and immersed and stirred at 25 ° C. for 6 hours. Further, when the pH of the treatment liquid was measured every hour from the start of the treatment to the end of the treatment, the pH of the treatment liquid remained at 5.1 at any measurement and did not vary. As a result of analyzing the carbon dioxide gas concentration in the treatment liquid, it was 20 mmol / L. After being immersed in the treatment solution for 6 hours and stirred, the obtained pellets were immediately drained and dried with hot air at 80 ° C. for 3 hours and subsequently at 107 ° C. for 24 hours to obtain dried EVOH pellets (water content) 0.2% by weight) was obtained.

  The alkali metal salt (A) in the obtained dried EVOH pellets was potassium, and the content of the alkali metal salt (A) was 5.4 μmol / g in terms of metal element. The content (d1) of the phosphoric acid compound (D) was 0.5 μmol / g in terms of phosphate radical. The content of the boron compound (B) in the obtained dry EVOH pellets was 242 ppm (22 μmol / g) in terms of boron element. The amount of carboxylic acid radical (C1) extracted by immersing the dried EVOH pellets in 95 ° C. pure water for 10 hours is 0 ppm (0 μmol / g), and 0.05 normal sodium hydroxide at 95 ° C. The amount of carboxylic acid (acetic acid) root (C2) extracted by immersion in an aqueous solution for 10 hours was 36 ppm (0.6 μmol / g). The MFR of the dried EVOH pellet is 1.6 g / 10 min. (Under 190 ° C. and 2160 g load).

  Using the obtained dry EVOH pellets, a single-layer film was prepared according to the above-described method, and a test for resistance to coloring and long run was performed. The evaluation results of the EVOH coloring resistance, 72-hour long run property, and 120-hour long run property of this example were all A. Moreover, content (d2) of the phosphoric acid compound (D) of a single layer film was 0.03 micromol / g in conversion of the phosphoric acid radical, and phosphorus element content (t) was 0.5 micromol / g. The content of the organophosphorus compound that can be extracted with chloroform was less than 0.01 μmol / g.

  When the obtained high-temperature colorability evaluation test was performed according to the above-described method using the obtained dry EVOH pellets, the evaluation was A determination. Moreover, when the odor test was done according to the above-mentioned method using the obtained dry EVOH pellet, all five monitors did not feel odor, and evaluation was A determination.

  Moreover, when the adhesive strength test was performed according to the above-mentioned method using the obtained dry EVOH pellets, the adhesive strength immediately after film formation was 760 g / 15 mm, and the adhesive strength after one week from film formation was 880 g / It was 15 mm, and good adhesive strength was obtained in all cases.

Example 9
50 kg of a 45% methanol solution of ethylene-vinyl acetate copolymer having an ethylene content of 27 mol% and 129 kg of methanol were charged into a 470 L saponification reactor, and the internal temperature was set to 60 ° C. while blowing nitrogen gas into the reactor. did. Thereto, 29 L (concentration: 80 g / L) of methanol solution of sodium hydroxide is added to start the saponification reaction. During the saponification reaction, methyl acetate generated as a by-product in the reaction system is continuously introduced into the reactor together with methanol in the reaction system in order to drive out the reaction system in order to increase the reaction efficiency. Nitrogen gas was continuously blown. The expelling speed was about 20 kg / hr in total of methyl acetate and methanol, and this was condensed and recovered using a cooling condenser. Two hours after the start of the reaction, 29 L of a methanol solution of sodium hydroxide (concentration: 80 g / L) was further added to drive the saponification reaction. Six hours after the start of the reaction, 6.8 kg of acetic acid and 56 L of water were added to neutralize the reaction solution to stop the reaction.

  The neutralized reaction solution was transferred from the reactor to a drum can and allowed to stand at room temperature for 16 hours to be cooled and solidified into a cake. Thereafter, the cake-like resin was drained using a centrifuge (manufactured by Kokusan Centrifuge Co., Ltd., H-130, rotation speed: 1200 rpm). Next, the step of decanting while continuously supplying ion-exchanged water from above to the center of the centrifuge and washing the resin with water was performed for 10 hours. The conductivity of the cleaning solution 10 hours after the start of cleaning was 30 μS / cm (measured with CM-30ET manufactured by Toa Denpa Kogyo).

  The granular EVOH thus obtained was dried at 60 ° C. for 48 hours using a dryer. 20 kg of dried granular EVOH was dissolved in 43 L of a water / methanol mixed solution (weight ratio: water / methanol = 5/5) with stirring at 80 ° C. for 12 hours. Next, the stirring was stopped and the temperature of the dissolution tank was lowered to 65 ° C. and left for 5 hours to degas the EVOH water / methanol solution. And it extrudes in a 5 degreeC water / methanol mixed solution (weight ratio: water / methanol = 9/1) from the metal plate which has a circular opening part with a diameter of 3.5 mm, precipitates in strand shape, and cuts. To obtain pellets having a diameter of about 4 mm and a length of about 5 mm.

  2.4 kg of the hydrous pellets thus obtained and 24 L of ion-exchanged water were placed in a plastic container having a height of 400 mm and an open diameter of 370 mm, washed with stirring at 25 ° C. for 2 hours, and then drained. Repeated twice. Next, an operation of adding 24 L of 1 g / L acetic acid aqueous solution to 2.4 kg of water-containing pellets, washing the mixture with stirring at 25 ° C. for 2 hours, and then removing the liquid was repeated twice. Further, 24 L of ion exchange water was added to 2.4 kg of the water-containing pellets, and the operation of washing with stirring at 25 ° C. for 2 hours and then draining was repeated 6 times. As a result of measuring the conductivity of the cleaning liquid after the sixth cleaning with CM-30ET manufactured by Toa Denpa Kogyo, the conductivity of the cleaning liquid was 3 μS / cm. The water content of the obtained EVOH pellets was 50% by weight.

  The thus-obtained EVOH after washing (ethylene content 27 mol%, saponification degree 99.98 mol% or more (calculated by NMR method), intrinsic viscosity 0.094 L / g) 2.4 kg hydrous pellets and concentration 0 . 5 L of 30 g / L boric acid aqueous solution was placed in a plastic container having a height of 300 mm and an opening diameter of 280 mm, immersed at 25 ° C. for 10 hours, and drained after immersion.

  Next, 5 L of ion-exchanged water was put in a plastic container having a height of 300 mm and an opening diameter of 280 mm. A silicon tube (inner diameter 7 mm, outer diameter 10 mm) was put into the ion-exchanged water in the container, and 0.5 L, 1 L / min. Bubbling at a speed of carbon dioxide was blown. Carbon dioxide was supplied using a carbon dioxide cylinder (liquefied carbon dioxide 30 kg manufactured by Nippon Carbon Co., Ltd.) and a flow meter (Model RK-1600R manufactured by KOFLOC). In the water into which the carbon dioxide gas was blown, 0.35 g of boric acid, 0.65 g of potassium hydrogen carbonate, and 0.85 g of potassium dihydrogen phosphate were dissolved, and further, 1 L / min. Carbon dioxide was continuously blown at a speed of. The treatment liquid had a boric acid content of 0.07 g / L, a potassium hydrogen carbonate content of 0.13 g / L, and a potassium dihydrogen phosphate content of 0.17 g / L. Moreover, when the pH of the said process liquid after blowing in carbon dioxide gas for 1 hour was measured using the pH meter (Metler MA235), the pH of the said process liquid was 5.0.

  Next, the blowing speed is 1 L / min. Then, 2.4 kg of the above water-containing pellets were added to the treatment liquid while blowing carbon dioxide gas, and immersed and stirred at 25 ° C. for 6 hours. Further, when the pH of the treatment liquid was measured every hour from the start of the treatment to the end of the treatment, the pH of the treatment liquid remained at 5 and remained unchanged at any measurement time. It was 20 mmol / L when the carbon dioxide gas density | concentration in a process liquid was analyzed. After being immersed in the treatment solution for 6 hours and stirred, the obtained pellets were immediately drained and dried with hot air at 80 ° C. for 3 hours and subsequently at 107 ° C. for 24 hours to obtain dried EVOH pellets (water content) 0.2% by weight) was obtained.

  The alkali metal salt (A) in the obtained dried EVOH pellets is potassium, the content of the alkali metal salt (A) is 2.6 μmol / g in terms of metal element, and the content of the phosphate compound (D) (D1) was 0.4 μmol / g in terms of phosphate radical.

  The content of the boron compound (B) in the obtained dry EVOH pellets was 160 ppm (15 μmol / g) in terms of boron element. The amount of carboxylic acid radical (C1) extracted by immersing the dried EVOH pellets in 95 ° C. pure water for 10 hours is 0 ppm (0 μmol / g), and 0.05 normal sodium hydroxide at 95 ° C. The amount of carboxylic acid (acetic acid) root (C2) extracted by immersion in an aqueous solution for 10 hours was 35 ppm (0.6 μmol / g). The MFR of the dried EVOH pellet is 4.0 g / 10 min. (210 ° C., 2160 g under load).

  Using the obtained dry EVOH pellets, a single-layer film was prepared according to the above-described method, and a test for resistance to coloring and long run was performed. The EVOH coloring resistance of this example was B, the 72 hour long run property was A, and the 120 hour long run evaluation result was B. Moreover, content (d2) of the phosphoric acid compound (D) of a single layer film was 0.02 micromol / g in conversion of a phosphoric acid radical, and phosphorus element content (t) was 0.4 micromol / g. The content of the organophosphorus compound that can be extracted with chloroform was less than 0.01 μmol / g.

  When the high temperature coloring property evaluation test was done according to the above-mentioned method using the obtained dry EVOH pellet, evaluation was B determination. Moreover, when the odor test was done according to the above-mentioned method using the obtained dry EVOH pellet, all five monitors did not feel odor, and evaluation was A determination.

  Moreover, when the adhesive strength test was performed according to the above-mentioned method using the obtained dry EVOH pellets, the adhesive strength immediately after film formation was 800 g / 15 mm, and the adhesive strength after one week from film formation was 950 g / It was 15 mm, and good adhesive strength was obtained in all cases.

Example 10
50 kg of a 45% methanol solution of ethylene-vinyl acetate copolymer having an ethylene content of 47 mol% and 129 kg of methanol were charged into a 470 L saponification reactor, and the internal temperature was set to 60 ° C. while blowing nitrogen gas into the reactor. did. Thereto, 29 L (concentration: 80 g / L) of methanol solution of sodium hydroxide is added to start the saponification reaction. During the saponification reaction, methyl acetate generated as a by-product in the reaction system is continuously introduced into the reactor together with methanol in the reaction system in order to drive out the reaction system in order to increase the reaction efficiency. Nitrogen gas was continuously blown. The expelling speed was about 20 kg / hr in total of methyl acetate and methanol, and this was condensed and recovered using a cooling condenser. Two hours after the start of the reaction, 29 L of a methanol solution of sodium hydroxide (concentration: 80 g / L) was further added to drive the saponification reaction. Six hours after the start of the reaction, 6.8 kg of acetic acid and 45 L of water were added to neutralize the reaction solution to stop the reaction.

  The neutralized reaction solution was transferred from the reactor to a drum can and allowed to stand at room temperature for 16 hours to be cooled and solidified into a cake. Thereafter, the cake-like resin was drained using a centrifuge (manufactured by Kokusan Centrifuge Co., Ltd., H-130, rotation speed: 1200 rpm). Next, the step of decanting while continuously supplying ion-exchanged water from above to the center of the centrifuge and washing the resin with water was performed for 10 hours. The conductivity of the cleaning solution 10 hours after the start of cleaning was 30 μS / cm (measured with CM-30ET manufactured by Toa Denpa Kogyo).

  The granular EVOH thus obtained was dried at 60 ° C. for 48 hours using a dryer. 20 kg of dried granular EVOH was dissolved in 43 L of a water / methanol mixed solution (weight ratio: water / methanol = 2/8) at 80 ° C. for 12 hours with stirring. Next, the stirring was stopped and the temperature of the dissolution tank was lowered to 65 ° C. and left for 5 hours to degas the EVOH water / methanol solution. And it extrudes in a 5 degreeC water / methanol mixed solution (weight ratio: water / methanol = 9/1) from the metal plate which has a circular opening part with a diameter of 3.5 mm, precipitates in strand shape, and cuts. To obtain pellets having a diameter of about 4 mm and a length of about 5 mm.

  2.4 kg of the hydrous pellets thus obtained and 24 L of ion-exchanged water were placed in a plastic container having a height of 400 mm and an open diameter of 370 mm, washed with stirring at 25 ° C. for 2 hours, and then drained. Repeated twice. Next, an operation of adding 24 L of 1 g / L acetic acid aqueous solution to 2.4 kg of water-containing pellets, washing the mixture with stirring at 25 ° C. for 2 hours, and then removing the liquid was repeated twice. Further, 24 L of ion exchange water was added to 2.4 kg of the water-containing pellets, and the operation of washing with stirring at 25 ° C. for 2 hours and then draining was repeated 6 times. As a result of measuring the conductivity of the cleaning liquid after the sixth cleaning with CM-30ET manufactured by Toa Denpa Kogyo, the conductivity of the cleaning liquid was 3 μS / cm. The water content of the obtained EVOH pellets was 50% by weight.

  The thus obtained EVOH after washing (ethylene content 47 mol%, saponification degree 99.98 mol% or more (calculated by NMR method), intrinsic viscosity 0.082 L / g) 2.4 kg hydrous pellets and concentration 0 . 5L of a 21 g / L boric acid aqueous solution was placed in a plastic container having a height of 300 mm and an opening diameter of 280 mm, immersed at 25 ° C. for 10 hours, and drained after immersion.

  Next, 5 L of ion-exchanged water was put in a plastic container having a height of 300 mm and an opening diameter of 280 mm. A silicon tube (inner diameter 7 mm, outer diameter 10 mm) was put into the ion-exchanged water in the container, and 0.5 L, 1 L / min. Bubbling at a speed of carbon dioxide was blown. Carbon dioxide was supplied using a carbon dioxide cylinder (liquefied carbon dioxide 30 kg manufactured by Nippon Carbon Co., Ltd.) and a flow meter (Model RK-1600R manufactured by KOFLOC). In the water into which the carbon dioxide gas was blown, 0.20 g of boric acid, 1.15 g of potassium hydrogen carbonate, and 0.55 g of potassium dihydrogen phosphate were dissolved, and further for 1 hour at 1 L / min. Carbon dioxide was continuously blown at a speed of. The treatment liquid had a boric acid content of 0.04 g / L, a potassium hydrogen carbonate content of 0.23 g / L, and a potassium dihydrogen phosphate content of 0.11 g / L. Moreover, when the pH of the said processing liquid after blowing in carbon dioxide gas for 1 hour was measured using the pH meter (Metler MA235), the pH of the said processing liquid was 5.2.

  Next, the blowing speed is 1 L / min. Then, 2.4 kg of the above water-containing pellets were added to the treatment liquid while blowing carbon dioxide gas, and immersed and stirred at 25 ° C. for 6 hours. Further, when the pH of the treatment liquid was measured every hour from the start of the treatment to the end of the treatment, the pH of the treatment liquid remained at 5.2 at any measurement and did not vary. It was 20 mmol / L when the carbon dioxide gas density | concentration in a process liquid was analyzed. After being immersed in the treatment solution for 6 hours and stirred, the obtained pellets were immediately drained and dried with hot air at 80 ° C. for 3 hours and subsequently at 107 ° C. for 24 hours to obtain dried EVOH pellets (water content) 0.2% by weight) was obtained.

  The alkali metal salt (A) in the obtained dried EVOH pellets is potassium, the content of the alkali metal salt (A) is 5.6 μmol / g in terms of metal element, and the content of the phosphoric acid compound (D) (D1) was 0.5 μmol / g in terms of phosphate radical.

  The content of the boron compound (B) in the obtained dry EVOH pellets was 110 ppm (10 μmol / g) in terms of boron element. The amount of carboxylic acid radical (C1) extracted by immersing the dried EVOH pellets in 95 ° C. pure water for 10 hours is 0 ppm (0 μmol / g), and 0.05 normal sodium hydroxide at 95 ° C. The amount of carboxylic acid (acetic acid) root (C2) extracted by immersion in an aqueous solution for 10 hours was 35 ppm (0.6 μmol / g). The MFR of the dried EVOH pellet is 6.2 g / 10 min. (Under 190 ° C. and 2160 g load).

  Using the obtained dry EVOH pellets, a single-layer film was prepared according to the above-described method, and a test for resistance to coloring and long run was performed. The evaluation results of the EVOH coloring resistance, 72-hour long run property, and 120-hour long run property of this example were all A. Moreover, content (d2) of the phosphoric acid compound (D) of a single layer film was 0.03 micromol / g in conversion of the phosphoric acid radical, and phosphorus element content (t) was 0.5 micromol / g. The content of the organophosphorus compound that can be extracted with chloroform was less than 0.01 μmol / g.

  When the obtained high-temperature colorability evaluation test was performed according to the above-described method using the obtained dry EVOH pellets, the evaluation was A determination. Moreover, when the odor test was done according to the above-mentioned method using the obtained dry EVOH pellet, all five monitors did not feel odor, and evaluation was A determination.

  Moreover, when the adhesive strength test was performed according to the above-mentioned method using the obtained dry EVOH pellets, the adhesive strength immediately after film formation was 700 g / 15 mm, and the adhesive strength after one week from film formation was 880 g / It was 15 mm, and good adhesive strength was obtained in all cases.

Comparative Example 1
2.4 kg of washed hydrous pellets obtained in the same manner as in Example 1 and 5.1 L of boric acid aqueous solution having a concentration of 0.36 g / L were placed in a plastic container having a height of 300 mm and an opening diameter of 280 mm, and 25 ° C. For 10 hours, and after immersion, the liquid was drained.

  Subsequently, the hydrated pellets after liquid removal were immersed in 5.1 L of an aqueous solution containing 0.56 g / L acetic acid and 0.025 g / L sodium acetate for 6 hours at 25 ° C. and stirred. Thereafter, the liquid was drained, and hot-air drying was performed at 80 ° C. for 3 hours and subsequently at 107 ° C. for 24 hours to obtain dry EVOH pellets (water content: 0.2 wt%). Various evaluations were performed in the same manner as in Example 1 using the obtained dried pellets. Table 2 shows the composition of the dry EVOH resin composition, and Table 3 shows the evaluation results.

Comparative Example 2
Dry EVOH pellets were produced in the same manner as in Comparative Example 1 except that the composition of the treatment liquid in which the washed water-containing pellets were immersed was changed as shown in Table 1. Various evaluations were performed in the same manner as in Example 1 using the obtained dried pellets. Table 2 shows the composition of the dry EVOH resin composition, and Table 3 shows the evaluation results.

Comparative Example 3
Comparative example of water-containing EVOH pellets containing 50% by weight of saponification catalyst residue having an ethylene content of 32 mol%, a saponification degree of 99.6 mol% (calculated from NMR method), and an intrinsic viscosity of 0.085 L / g Washed as in 1.

  A dry EVOH pellet was prepared in the same manner as in Comparative Example 1 except that the above prepared hydrous pellet was used as the hydrous pellet and the composition of the liquid in which the obtained hydrous pellet was immersed was changed as shown in Table 1. Various evaluations were performed in the same manner as in Example 1 using the obtained dried pellets. Table 2 shows the composition of the dry EVOH resin composition, and Table 3 shows the evaluation results.

Comparative Example 4
Dry EVOH pellets were produced in the same manner as in Comparative Example 1 except that the composition of the treatment liquid in which the washed water-containing pellets were immersed was changed as shown in Table 1. Various evaluations were performed in the same manner as in Example 1 using the obtained dried pellets. Table 2 shows the composition of the dry EVOH resin composition, and Table 3 shows the evaluation results.

  Moreover, although EVOH which changed ethylene content from 27 mol% to 47 mol% was used in Examples 7-10, content of alkali metal salt (A) is included, so that ethylene content becomes large from past experience. It has been found that increasing amounts are preferred. Based on such knowledge, the content of alkali metal (A) in Examples 7 to 10 of this time was blended with an amount of alkali metal salt (A) that seems to be optimal for each ethylene content. is there.

  FIG. 1 is a graph showing the relationship between the ethylene content (ET) and the alkali metal salt (A) content (a) in Examples 7 to 10. When an approximate curve was obtained by exponential approximation from the plotted four points of data, an approximate expression of “a = 0.95 × exp (0.039 × ET)” was obtained. The alkali metal salt (A) having a width in the range of 2 μmol / g above and below is preferable.

It is the graph which showed the relationship between ethylene content (ET) and alkali metal salt (A) content (a) in Examples 7-10.

Claims (11)

Containing 0.1 to 20 μmol / g of alkali metal salt (A) in terms of alkali metal, 0 to 2 μmol / g of carboxylic acid group (C1) extracted by immersion in 95 ° C. water for 10 hours, and A film or sheet comprising an ethylene-vinyl alcohol copolymer resin composition containing 0 to 40 μmol / g of a carboxylic acid group (C2) extracted by immersing in a 0.05 N aqueous sodium hydroxide solution at 95 ° C. for 10 hours. Containing 0.1 to 20 μmol / g of alkali metal salt (A) in terms of alkali metal, 0 to 2 μmol / g of carboxylic acid group (C1) extracted by immersion in 95 ° C. water for 10 hours, and A film or sheet comprising an ethylene-vinyl alcohol copolymer resin composition having a saponification degree of 99.7 to 100 mol%. The ratio (d / t) of the content (d: μmol / g) of the phosphate compound (D) in terms of phosphate radicals to the phosphorus element content (t: μmol / g) is 0.4 or less, A film or sheet comprising an ethylene-vinyl alcohol copolymer resin composition substantially free of an organic phosphorus compound extractable with chloroform. The film or sheet according to any one of claims 1 to 3, comprising a potassium salt as the alkali metal salt (A) in an amount of 0.1 to 20 µmol / g in terms of potassium. The film or sheet according to any one of claims 1 to 4, wherein the boron compound (B) is contained in an amount of 1 to 200 µmol / g in terms of boron element. The film or sheet according to any one of claims 1 to 5, wherein the phosphorus element content (t) is 0.05 to 5 µmol / g in terms of phosphorus element. The film or sheet according to any one of claims 1 to 6, comprising a multilayer structure having a layer of the ethylene-vinyl alcohol copolymer resin composition and a layer of another resin. A molded product obtained by thermoforming the film or sheet according to claim 7. After bringing the ethylene-vinyl alcohol copolymer resin into contact with an aqueous solution containing at least one additive selected from the group consisting of an alkali metal salt (A) and a boron compound (B) and containing carbon dioxide gas A method for producing a film or sheet by extrusion. The method for producing a film or sheet according to claim 9, wherein the film or sheet is coextruded with another thermoplastic resin. The ratio (d / t) of the content (d: μmol / g) of the phosphate compound (D) in terms of phosphate radicals to the phosphorus element content (t: μmol / g) is 0.4 or less, A melt-molded article comprising an ethylene-vinyl alcohol copolymer resin composition substantially free of an organophosphorus compound extractable with chloroform.

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