JP7318153B1 - Method for producing modified ethylene-vinyl alcohol copolymer - Google Patents

Abstract

Using a catalyst solution (D) which is an acetone solution containing zinc ions (F) and sulfonate ions, an ethylene-vinyl alcohol copolymer (A) and a monovalent epoxy compound (B) having 2 to 8 carbon atoms are reacted. A method for producing a modified ethylene-vinyl alcohol copolymer (C), wherein the reaction is performed by melt-kneading in an extruder. At this time, it is preferable to use 0.05 to 1.0 μmol/g of zinc ion (F) in terms of the number of moles relative to the mass of the ethylene-vinyl alcohol copolymer (A). It is also preferable to add a mixture of the monovalent epoxy compound (B) and the catalyst solution (D) to the molten ethylene-vinyl alcohol copolymer (A). This provides a method for producing a modified EVOH having excellent barrier properties, stretchability, etc., and excellent melt stability.

Description

The present invention relates to a method for producing a modified ethylene-vinyl alcohol copolymer. Moreover, it is related with the manufacturing method of the resin composition containing the said copolymer. Furthermore, it relates to a method for producing mixed pellets containing pellets of the copolymer. The present invention also relates to a resin composition containing a modified ethylene-vinyl alcohol copolymer.

Ethylene-vinyl alcohol copolymers (hereinafter sometimes abbreviated as EVOH) are excellent in transparency and gas barrier properties, but have the drawback of lacking stretchability and bending resistance. In order to improve this drawback, a method of blending EVOH with a flexible resin such as an ethylene-vinyl acetate copolymer or an ethylene-propylene copolymer is known. However, this method has the drawback that the transparency is greatly reduced.

In Patent Document 1, EVOH and a monovalent epoxy compound having a molecular weight of 500 or less are melt-kneaded in an extruder in the presence of a catalyst containing ions of metals belonging to groups 3 to 12 of the periodic table. A method for producing modified EVOH containing 0.3 to 40 mol % of structural unit (I) is described. The modified EVOH is said to be excellent in barrier properties, transparency, stretchability and bending resistance.

In an example of Patent Document 1, a catalyst solution was prepared by dissolving equimolar amounts of zinc acetylacetonate monohydrate and trifluoromethanesulfonic acid in 1,2-dimethoxyethane, and this catalyst solution and a monovalent epoxy compound were dissolved. is fed to the extruder and more structural units (I) can be introduced into the EVOH than when no catalyst solution is added. It also describes that deterioration of the thermal stability of the resulting modified EVOH can be suppressed by using trisodium ethylenediaminetetraacetate trihydrate as a catalyst deactivator. The modified EVOH thus obtained contained 120-150 ppm (1.9-2.3 μmol/g) of zinc ions as catalyst residues.

Further, Patent Document 2 describes a resin composition containing modified EVOH containing 0.3 to 40 mol % of structural unit (I) and other thermoplastic resin. It describes an example of a resin composition containing the modified EVOH and unmodified EVOH and an example of a resin composition containing the modified EVOH and polyolefin.

WO 02/092643 A1 WO 03/072653 A1

However, the modified EVOH described in Patent Literature 1 tends to be colored and, when melt-kneaded for a long period of time, has a large torque fluctuation and has a problem of melt stability. The present invention was made in order to solve such problems, and an object of the present invention is to provide a method for producing a modified EVOH that is excellent in barrier properties, stretchability, etc., and is also excellent in melt stability. is. It is also an object of the present invention to provide a method of making resin compositions containing such modified EVOH and other resins. It is also an object of the present invention to provide a method for producing mixed pellets containing such modified EVOH pellets and other resin pellets. It is also an object of the present invention to provide resin compositions containing such modified EVOH.

The above problem is solved by using a catalyst solution (D), which is an acetone solution containing zinc ions (F) and sulfonate ions, to prepare an ethylene-vinyl alcohol copolymer (A) and a monovalent epoxy compound having 2 to 8 carbon atoms ( The solution is provided by providing a method for producing a modified ethylene-vinyl alcohol copolymer (C), in which B) is reacted by melt-kneading in an extruder.

In the production method, the ethylene-vinyl alcohol copolymer (A), the monofunctional epoxy compound (B), and the catalyst solution (D) are introduced into an extruder and melt-kneaded in the extruder to obtain It is preferable to react the ethylene-vinyl alcohol copolymer (A) with the monovalent epoxy compound (B). At this time, it is preferable to add a mixture of the monovalent epoxy compound (B) and the catalyst solution (D) to the molten ethylene-vinyl alcohol copolymer (A).

In the production method, the ethylene-vinyl alcohol copolymer (A) is impregnated with the catalyst solution (D), introduced into an extruder, and melt-kneaded with the monovalent epoxy compound (B) in the extruder. Therefore, it is also preferable to react the ethylene-vinyl alcohol copolymer (A) with the monovalent epoxy compound (B).

In the production method described above, it is preferable that the ethylene-vinyl alcohol copolymer (A) has an ethylene content of 5 to 55 mol % and a degree of saponification of 90 mol % or more. It is also preferable to melt-knead 1 to 50 parts by mass of the monofunctional epoxy compound (B) with 100 parts by mass of the ethylene-vinyl alcohol copolymer (A). It is also preferable to use zinc ions (F) in an amount of 0.05 to 1.0 μmol/g in terms of number of moles relative to the mass of the ethylene-vinyl alcohol copolymer (A).

In a preferred embodiment, the ethylene-vinyl alcohol copolymer (A) and the monovalent epoxy compound (B) are melt-kneaded, then the catalyst deactivator (E) is added, and the mixture is further melt-kneaded. At this time, the catalyst deactivator (E) is preferably a chelating agent. It is also preferred that the catalyst deactivator (E) is a metal salt. It is also preferable that the ratio (E/F) of the number of moles of the catalyst deactivator (E) to the number of moles of zinc ions (F) contained in the catalyst solution (D) is 1.5-40. Further, the ethylene-vinyl alcohol copolymer (A) and the monovalent epoxy compound (B) are melt-kneaded, and after removing the unreacted monovalent epoxy compound (B), the catalyst deactivator (E) is added. is also preferred.

It is preferable that the modified ethylene-vinyl alcohol copolymer (C) obtained by the above production method contains 0.3 to 40 mol % of the structural unit (I) represented by the following formula (I).

(In formula (I), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an alicyclic carbonized group having 3 to 6 carbon atoms. represents a hydrogen group or a phenyl group, and the aliphatic hydrocarbon group, alicyclic hydrocarbon group and phenyl group may have a hydroxyl group, an alkoxy group, a carboxyl group or a halogen atom, and R ³ and R ⁴ are may be combined).

A method for producing a resin composition comprising a step of melt-kneading the modified ethylene-vinyl alcohol copolymer (C) obtained by the production method and an unmodified ethylene-vinyl alcohol copolymer or polyolefin is the method of the present invention. This is the preferred embodiment. Further, a step of pelletizing the modified ethylene-vinyl alcohol copolymer (C) obtained by the above production method, pellets of the obtained modified ethylene-vinyl alcohol copolymer (C), and unmodified ethylene-vinyl alcohol A method of making mixed pellets comprising dry blending with copolymer or polyolefin pellets is also a preferred embodiment of the present invention.

Further, the above object includes a modified ethylene-vinyl alcohol copolymer (C) containing 2 to 40 mol% of structural units (I) represented by the following formula (I) and zinc ions (F), and zinc ions ( The problem is also solved by providing a resin composition in which the content of F) is 0.05 to 1.0 μmol/g.

(In formula (I), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an alicyclic carbonized group having 3 to 6 carbon atoms. represents a hydrogen group or a phenyl group, and the aliphatic hydrocarbon group, alicyclic hydrocarbon group and phenyl group may have a hydroxyl group, an alkoxy group, a carboxyl group or a halogen atom, and R ³ and R ⁴ are may be combined).

At this time, it is preferable that the resin composition further contains an alkali metal ion (G), and the molar ratio (G/F) of the alkali metal ion (G) to the zinc ion (F) is 5 to 80. .

According to the method for producing a modified EVOH of the present invention, a modified EVOH having excellent barrier properties, stretchability, etc. and excellent melt stability can be produced. Moreover, according to the method for producing a resin composition of the present invention, a resin composition containing modified EVOH and other resins can be produced. Further, according to the method for producing mixed pellets of the present invention, mixed pellets containing modified EVOH pellets and other resin pellets can be produced. Furthermore, the resin composition of the present invention contains a low amount of catalyst residue while containing a highly modified EVOH. Therefore, it has excellent barrier properties, stretchability, and the like, and also has excellent melt stability and is less likely to be colored.

It is a schematic diagram showing the configuration of an extruder used in Examples.

Modified EVOH (C) produced by the method of the present invention is a reaction product of EVOH (A) and monovalent epoxy compound (B), and preferably contains the following structural unit (I).

In formula (I), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an alicyclic hydrocarbon group having 3 to 6 carbon atoms. or a phenyl group, and the aliphatic hydrocarbon group, alicyclic hydrocarbon group and phenyl group may have a hydroxyl group, an alkoxy group, a carboxyl group or a halogen atom, and R ³ and R ⁴ are bonded You may have

Aliphatic hydrocarbon groups include alkyl groups and alkenyl groups. A cycloalkyl group and a cycloalkenyl group are mentioned as an alicyclic hydrocarbon group.

In a more preferred embodiment, both R ¹ and R ² are hydrogen atoms. In a further preferred embodiment, both R ¹ and R ² are hydrogen atoms, and one of R ³ and R ⁴ is an aliphatic hydrocarbon group having 1 to 6 carbon atoms and the other is hydrogen is an atom. Preferably, said aliphatic hydrocarbon group is an alkyl or alkenyl group. From the viewpoint of emphasizing gas barrier properties when the modified EVOH (C) is used as a barrier material, it is more preferable that one of R ³ and R ⁴ is a methyl group or an ethyl group and the other is a hydrogen atom. preferable.

Further, from the viewpoint of gas barrier properties when the modified EVOH (C) is used as a barrier material, both R ¹ and R ² are hydrogen atoms, and one of R ³ and R ⁴ is (CH ₂ ). It is also preferred that a substituent represented by _i OH (where i is an integer of 1 to 6) and the other is a hydrogen atom. When the gas barrier properties of the barrier material are particularly important, i in the substituent represented by (CH ₂ ) _i OH is preferably an integer of 1 to 4, more preferably 1 or 2. It is preferably 1, more preferably 1.

The amount of the structural unit (I) contained in the modified EVOH (C) is preferably 0.3 to 40 mol %. The lower limit of the amount of structural unit (I) is more preferably 0.5 mol % or more, still more preferably 1 mol % or more, and particularly preferably 2 mol % or more. On the other hand, the upper limit of the amount of structural unit (I) is more preferably 20 mol % or less, still more preferably 15 mol % or less, and particularly preferably 10 mol % or less. When the amount of structural unit (I) contained is within the above range, modified EVOH (C) having gas barrier properties, transparency, stretchability and flex resistance can be obtained.

The modified EVOH (C) preferably has an ethylene content of 5 to 55 mol %. From the viewpoint of obtaining good stretchability and flex resistance of the modified EVOH (C), the lower limit of the ethylene content of the modified EVOH (C) is more preferably 10 mol% or more, more preferably 20 mol. % or more, more preferably 25 mol % or more, and particularly preferably 31 mol % or more. On the other hand, from the viewpoint of the gas barrier properties of the modified EVOH (C) of the present invention, the upper limit of the ethylene content of the modified EVOH (C) is more preferably 50 mol% or less, more preferably 45 mol% or less. be. If the ethylene content is less than 5 mol %, the melt moldability may deteriorate, and if it exceeds 55 mol %, the gas barrier properties may be insufficient. Further, the degree of saponification of modified EVOH (C) means the degree of saponification of EVOH (A) described later.

Monomer units other than the structural unit (I) and ethylene units constituting the modified EVOH (C) are mainly vinyl alcohol units. This vinyl alcohol unit is usually a vinyl alcohol unit that did not react with the monovalent epoxy compound (B) among the vinyl alcohol units contained in the raw material EVOH (A). In addition, unsaponified vinyl acetate units that may be contained in EVOH (A) are usually contained as they are in modified EVOH (C). The content of vinyl alcohol units is preferably 40 to 80 mol %. From the viewpoint of obtaining good gas barrier properties from the modified EVOH (C) of the present invention, the lower limit of the vinyl alcohol unit content of the modified EVOH (C) is more preferably 45 mol % or more, and more preferably 50 mol % or more. On the other hand, from the viewpoint of obtaining good stretchability and bending resistance of the modified EVOH (C) of the present invention, the upper limit of the vinyl alcohol unit content of the modified EVOH (C) is more preferably 75 mol % or less. and more preferably 70 mol % or less.

Modified EVOH (C) is a random copolymer containing these monomer units. Furthermore, other monomeric units may be included within the range that does not hinder the object of the present invention, but monomeric units other than structural unit (I), ethylene units, vinyl alcohol units and vinyl acetate units The content of is preferably 5 mol% or less, more preferably 3 mol% or less, further preferably 2 mol% or less, and may be 1 mol% or less, substantially Other monomeric units may not be included. Other monomer units include those exemplified as copolymerizable monomers described later in EVOH (A).

A preferred melt flow rate (MFR) (190° C., under 2160 g load) of the modified EVOH (C) is 0.1 to 30 g/10 min, more preferably 0.3 to 25 g/10 min, more preferably is 0.5 to 20 g/10 minutes. However, if the melting point is around 190°C or above 190°C, it is measured at multiple temperatures above the melting point under a load of 2160 g. Expressed as a value extrapolated to 190°C.

The present invention relates to a method for producing the modified EVOH (C). In the present invention, an ethylene-vinyl alcohol copolymer (A) and a monovalent epoxy compound ( B) is melt-kneaded in an extruder to produce a modified ethylene-vinyl alcohol copolymer (C).

The EVOH (A) used in the present invention is preferably obtained by saponifying an ethylene-vinyl ester copolymer. Vinyl acetate is a typical vinyl ester used in the production of EVOH, but other fatty acid vinyl esters (vinyl propionate, vinyl pivalate, etc.) can also be used. Monomers copolymerizable with ethylene and vinyl esters, such as alkenes such as propylene, butylene, pentene, and hexene; 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1 -butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3 , 4-diacyloxy-2-methyl-1-butene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diacyloxy-1-pentene, 4-acyloxy-1-hexene, 5-acyloxy -1-hexene, 6-acyloxy-1-hexene, 5,6-diacyloxy-1-hexene, 1,3-diacetoxy-2-methylenepropane and other alkenes having an ester group or saponified products thereof; acrylic acid, methacrylic acid , crotonic acid, unsaturated acids such as itaconic acid or their anhydrides, salts, or mono- or dialkyl esters; acrylonitrile, nitriles such as methacrylonitrile; amides such as acrylamide, methacrylamide; vinylsulfonic acid, allylsulfonic acid, Olefinsulfonic acids such as methallylsulfonic acid or salts thereof; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxy-ethoxy)silane, γ-methacryloxypropylmethoxysilane and other vinylsilane compounds; alkyl vinyl ethers, vinyl ketones, It is also possible to co-polymerize a small amount of N-vinylpyrrolidone, vinyl chloride, vinylidene chloride, or the like. The amount of copolymerization in that case is usually 5 mol % or less, and it is preferred that it is substantially absent.

The ethylene content of EVOH (A) used in the present invention is preferably 5 to 55 mol %. From the viewpoint of obtaining good stretchability and bending resistance of the modified EVOH (C), the lower limit of the ethylene content of the EVOH (A) is more preferably 10 mol% or more, more preferably 20 mol%. or more, particularly preferably 25 mol % or more, more preferably 31 mol % or more. On the other hand, from the viewpoint of the gas barrier properties of the modified EVOH (C) of the present invention, the upper limit of the ethylene content of the EVOH (A) is more preferably 50 mol% or less, more preferably 45 mol% or less. . If the ethylene content is less than 5 mol %, the melt moldability may deteriorate, and if it exceeds 55 mol %, the gas barrier properties may be insufficient. Here, when the EVOH (A) is a blend of two or more EVOHs with different ethylene contents, the average value calculated from the blending mass ratio is taken as the ethylene content.

The degree of saponification of the vinyl ester component of EVOH (A) used in the present invention is preferably 90 mol % or more. The degree of saponification of the vinyl ester component is more preferably 95 mol% or more, still more preferably 98 mol% or more, and most preferably 99 mol% or more. If the degree of saponification is less than 90 mol%, the gas barrier properties of the modified EVOH (C), especially at high humidity, may be lowered, and the thermal stability may be insufficient, resulting in gels and grains in the molded product. may become more likely to occur. Here, when the EVOH (A) is a blend of two or more EVOHs with different degrees of saponification, the average value calculated from the blending mass ratio is taken as the degree of saponification. The ethylene content and saponification degree of EVOH (A) can be obtained by nuclear magnetic resonance (NMR) method.

Furthermore, as EVOH (A), EVOH blended with a boron compound can also be used within a range that does not interfere with the object of the present invention. Examples of boron compounds include boric acids, borate esters, borates, and boron hydrides. Specifically, 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, borax, and the like. Among these compounds, orthoboric acid (hereinafter sometimes simply referred to as boric acid) is preferred.

When EVOH blended with a boron compound is used as EVOH (A), the content of the boron compound is preferably 20 to 2000 ppm, more preferably 50 to 1000 ppm in terms of boron element. By blending the boron compound within this range, it is possible to obtain EVOH with suppressed torque fluctuation during heating and melting. If it is less than 20 ppm, such effect is small, and if it exceeds 2000 ppm, gelation tends to occur, resulting in poor moldability.

EVOH (A) containing a phosphoric acid compound may also be used as EVOH (A). In some cases, this can stabilize the quality (coloration, etc.) of the resin. The phosphoric acid compound used in the present invention is not particularly limited, and various acids such as phosphoric acid and phosphorous acid, salts thereof, and the like can be used. The phosphate may be contained in any form of primary phosphate, secondary phosphate, and tertiary phosphate, but primary phosphate is preferred. Although the cationic species is not particularly limited, it is preferably an alkali metal salt. Among these, sodium dihydrogen phosphate and potassium dihydrogen phosphate are preferred. However, when the EVOH (A) and the monovalent epoxy compound (B) are reacted using a catalyst solution (D) containing zinc ions as described later, the phosphate deactivates the catalyst. Smaller amounts are preferred. Therefore, the content of the phosphate compound in EVOH (A) is preferably 200 ppm or less, more preferably 100 ppm or less, and most preferably 50 ppm or less in terms of phosphate radicals. A suitable lower limit when blending a phosphoric acid compound is 5 ppm or more.

As will be described later, in the method for producing modified EVOH (C) of the present invention, the EVOH (A) and the monofunctional epoxy compound (B) are melt-kneaded in an extruder using the catalyst solution (D). During the reaction, EVOH is exposed to heating conditions. At this time, if EVOH (A) contains an excessive amount of alkali metal salt and/or alkaline earth metal salt, the catalyst is deactivated, so the addition amount thereof is preferably small. Therefore, it is preferable that the alkali metal salt contained in EVOH (A) is 50 ppm or less in terms of metal element. In a more preferred embodiment, the alkali metal salt contained in EVOH (A) is 30 ppm or less, more preferably 20 ppm or less, in terms of metal element. From the same point of view, the alkaline earth metal salt contained in EVOH (A) is preferably 20 ppm or less, more preferably 10 ppm or less, in terms of metal element.

The intrinsic viscosity of EVOH (A) used in the present invention is preferably 0.06 L/g or more. The intrinsic viscosity of EVOH (A) is more preferably in the range of 0.07 to 0.2 L/g, still more preferably 0.075 to 0.15 L/g, particularly preferably 0.080 to 0.080. 12 L/g. If the intrinsic viscosity of EVOH (A) is less than 0.06 L/g, stretchability and flex resistance may deteriorate. Further, when the intrinsic viscosity of EVOH (A) exceeds 0.2 L/g, there is a possibility that gels and lumps are likely to occur in molded articles made of modified EVOH (C).

The EVOH (A) used in the present invention preferably has a melt flow rate (MFR) (190° C., under 2160 g load) of 0.1 to 30 g/10 min, more preferably 0.3 to 25 g/10 min. , more preferably 0.5 to 20 g/10 minutes. However, if the melting point is around 190°C or above 190°C, it is measured at multiple temperatures above the melting point under a load of 2160 g. Expressed as a value extrapolated to 190°C. A mixture of two or more EVOHs having different MFRs can also be used.

The monovalent epoxy compound (B) used in the present invention must be a monovalent epoxy compound. That is, it must be an epoxy compound having only one epoxy group in the molecule. The effects of the present invention cannot be obtained when a polyvalent epoxy compound having a divalent or higher valence is used. However, in the manufacturing process of the monovalent epoxy compound, a very small amount of the polyepoxy compound may be contained. A monovalent epoxy compound containing a very small amount of polyepoxy compound can be used as the monovalent epoxy compound (B) in the present invention as long as it does not impair the effects of the present invention.

The monovalent epoxy compound (B) used in the present invention has 2 to 8 carbon atoms. Specifically, compounds represented by the following formulas (II) to (IV) are preferably used.

In the formula, R ⁵ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms or a phenyl group. R ⁶ and R ⁷ each represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a cycloalkyl group having 3 to 5 carbon atoms. Also, i represents an integer of 1-6.

The number of carbon atoms in the monovalent epoxy compound is preferably 2-6, more preferably 2-4. From the viewpoint of the gas barrier properties of the resulting modified EVOH (C), the monofunctional epoxy compound is more preferably epoxyethane, epoxypropane, 1,2-epoxybutane and glycidol, and more preferably epoxypropane and 1,2-epoxybutane. .

A modified EVOH (C) is obtained by reacting the EVOH (A) with the monovalent epoxy compound (B). At this time, a suitable mixing ratio of EVOH (A) and monovalent epoxy compound (B) is 1 to 50 parts by mass of (B) per 100 parts by mass of (A), more preferably (A) 2 to 40 parts by mass of (B) per 100 parts by mass, and particularly preferably 5 to 35 parts by mass of (B) per 100 parts by mass of (A).

The catalyst solution (D) used when reacting the EVOH (A) and the monovalent epoxy compound (B) is an acetone solution containing zinc ions (F) and sulfonate ions. By melt-kneading using such a catalyst solution, the EVOH (A) and the monovalent epoxy compound (B) can be efficiently reacted.

The catalyst solution (D) used in the present invention contains zinc ions (F). The most important thing as a metal ion used in the catalyst solution (D) is to have moderate Lewis acidity, and zinc ion (F) is used from this point. By using zinc ions (F), the catalytic activity is high and the thermal stability of the resulting modified EVOH (C) is excellent.

The amount of zinc ions (F) added is preferably 0.05 to 1.0 μmol/g in terms of the number of moles of zinc ions (F) with respect to the mass of EVOH (A). If the amount of zinc ions (F) is too large, when the resulting modified EVOH (C) is melt-kneaded over a long period of time, the torque fluctuates greatly, resulting in a problem of melt stability. Moreover, the resulting modified EVOH (C) may be colored. The number of moles of zinc ions (F) is more preferably 0.9 μmol/g or less. On the other hand, if the amount of zinc ions (F) is too small, the effect of adding the catalyst (D) may not be sufficiently exhibited, and it is more preferably 0.1 μmol/g or more, and still more preferably 0.2 μmol/g. /g or more, more preferably 0.35 μmol/g or more.

The catalyst solution (D) contains sulfonate ions in addition to zinc ions (F). The sulfonate ion acts as a counter ion for the zinc ion (F), and improves the Lewis acidity of the zinc ion (F), thereby improving the catalytic activity. The sulfonate ion does not react with the hydroxyl group or epoxy group of EVOH, and is thermally stable as an anion species itself. The sulfonate ion is exemplified by methanesulfonate ion, ethanesulfonate ion, trifluoromethanesulfonate ion, benzenesulfonate ion, toluenesulfonate ion, etc. Trifluoromethanesulfonate ion is most suitable.

In the examples of Patent Document 1, a catalyst solution is used in which equimolar amounts of zinc acetylacetonate monohydrate and trifluoromethanesulfonic acid are dissolved in 1,2-dimethoxyethane. That is, the number of moles of sulfonate ions contained in the catalyst solution was one times the number of moles of zinc ions (F). In contrast, in the present invention, the number of moles of sulfonate ions contained in the catalyst solution (D) is preferably 1.2 to 4 times the number of moles of zinc ions (F). By including a larger amount of sulfonate ions as counter ions for the zinc ions (F), the Lewis acidity of the zinc ions (F) is improved, and the reaction can proceed smoothly with a smaller amount of catalyst. The number of moles of sulfonate ions to the number of moles of zinc ions (F) is more preferably 1.5 times or more, more preferably 1.8 times or more. Also, it is more preferably 3 times or less, more preferably 2.5 times or less. It is optimal that the amount is substantially doubled, and at this time, divalent zinc ions and monovalent sulfonate ions can form a salt in just the right amount. Since neither the zinc ion (F) nor the sulfonate ion are volatilized, the ratio of both here is maintained at the same value even in the modified EVOH composition.

In the catalyst solution (D), the solvent for dissolving zinc ions (F) and sulfonate ions is acetone. In Patent Document 1, it is said that it is preferable to use an ether-based solvent, and an example using a catalyst solution obtained by dissolving zinc acetylacetonate monohydrate and trifluoromethanesulfonic acid in 1,2-dimethoxyethane was used. is described. However, when 1,2-dimethoxyethane is used as the solvent, the resulting modified EVOH (C) is likely to be colored, and when the modified EVOH (C) is melt-kneaded for a long time, torque fluctuations are large and melting occurs. It also had problems with stability. In addition, the ignition point of 1,2-dimethoxyethane is 202° C., which is close to the melt-kneading temperature, and poses a danger during production. In contrast, by using acetone as a solvent, the reaction can proceed with a smaller amount of catalyst, and the amount of zinc ions (F) contained in the resulting modified EVOH (C) can be reduced. This can improve the problems of coloration and melt stability. Furthermore, the ignition point of acetone is 540° C., which greatly reduces the danger during production. The catalyst solution (D) may contain a small amount of solvent other than acetone. Such other solvent can be dissolved in acetone and does not interfere with the present invention, and is exemplified by methanol and the like. Its content is usually 20% by mass or less, preferably 10% by mass or less, and more preferably 5% by mass or less.

In the method for producing modified EVOH (C) of the present invention, the catalyst solution (D), which is an acetone solution containing zinc ions (F) and sulfonate ions, is used to prepare EVOH (A) and a monovalent epoxy compound (B). are reacted by melt-kneading in an extruder. As the method, the following two methods are exemplified.

In the first method, EVOH (A), a monovalent epoxy compound (B), and a catalyst solution (D) are introduced into an extruder and melt-kneaded in the extruder to obtain EVOH (A) and In this method, a modified EVOH (C) is obtained by reacting it with a monovalent epoxy compound (B). At this time, it is preferable to add a mixture of the monovalent epoxy compound (B) and the catalyst solution (D) to the molten EVOH (A).

In the second method, EVOH (A) is impregnated with a catalyst solution (D), introduced into an extruder, and melt-kneaded with a monofunctional epoxy compound (B) in the extruder to obtain EVOH (A ) and a monovalent epoxy compound (B) to obtain a modified EVOH (C). As a method for impregnating EVOH (A) with the catalyst solution (D), a method of contacting pellets of EVOH (A) with the catalyst solution (D) and then drying is preferably mentioned. In this case, the dry pellets thus obtained are introduced into an extruder.

The extruder used for reacting the EVOH (A) and the monovalent epoxy compound (B) in the extruder is not particularly limited, but may be a single screw extruder, a twin screw extruder or a multi-screw extruder with two or more screws. is used, and the temperature in the extruder is set to 180 to 250° C., and the EVOH (A) and the monofunctional epoxy compound (B) are preferably reacted. When the temperature inside the extruder exceeds 250°C, EVOH may deteriorate, and the temperature is more preferably 230°C or less. On the other hand, if the temperature is less than 180°C, the reaction between EVOH (A) and the monofunctional epoxy compound (B) may not proceed sufficiently, and the temperature is more preferably 190°C or higher.

When using a twin-screw extruder or a multi-screw extruder with two or more screws, it is easy to increase the pressure in the reaction section by changing the screw configuration, and the EVOH (A) and the monofunctional epoxy compound (B) reaction can be carried out efficiently. In a single-screw extruder, it is possible to increase the pressure in the reaction section by connecting two or more extruders and arranging a valve in the resin flow path between them. Similarly, two or more twin-screw extruders or multi-screw extruders having two or more screws may be connected to manufacture.

Since many of the monovalent epoxy compounds (B) used in the present invention have a low boiling point, there is a risk that the monovalent epoxy compound (B) will volatilize outside the system when the reaction system is heated in a production method using a solution reaction. There is However, by allowing the EVOH (A) and the monovalent epoxy compound (B) to react within the extruder, it is possible to suppress volatilization of the monovalent epoxy compound (B) out of the system. In particular, when the monovalent epoxy compound (B) is added into the extruder, the reactivity between the EVOH (A) and the monovalent epoxy compound (B) is increased by pressurizing the extruder under pressure, and the monovalent epoxy compound is It is possible to remarkably suppress volatilization of (B) out of the system.

The method of mixing the EVOH (A) and the monofunctional epoxy compound (B) during the reaction in the extruder is not particularly limited. Suitable examples include a method of spraying, a method of feeding EVOH (A) to an extruder, and a method of contacting the monofunctional epoxy compound (B) in the extruder. Among these, from the viewpoint of suppressing volatilization of the monovalent epoxy compound (B) to the outside of the system, after feeding EVOH (A) to the extruder, the monovalent epoxy compound (B ) is preferred. The position at which the monovalent epoxy compound (B) is added into the extruder is also arbitrary, but from the viewpoint of the reactivity between the EVOH (A) and the monovalent epoxy compound (B), the molten EVOH (A) It is preferable to add the monohydric epoxy compound (B).

In the step of adding the monovalent epoxy compound (B), it is preferable to press-fit the monovalent epoxy compound (B) under pressure. At this time, if the pressure is insufficient, problems such as a decrease in the reaction rate and variations in the ejection amount occur. The required pressure varies greatly depending on the boiling point of the monofunctional epoxy compound (B) and the extrusion temperature, but is usually preferably in the range of 0.5-30 MPa, more preferably in the range of 1-20 MPa. The same is true when adding a mixture of the monovalent epoxy compound (B) and the catalyst solution (D).

The position where the catalyst solution (D) is introduced into the extruder is not particularly limited, but it is preferable to add it at a position where the EVOH (A) is completely melted, so that it can be blended uniformly. It is preferably added at the same location as or near the location where the monofunctional epoxy compound (B) is added. By blending the catalyst solution (D) and the monovalent epoxy compound (B) almost simultaneously, the deterioration of the EVOH (A) due to the influence of the Lewis acid zinc ion (F) can be minimized. This is because a sufficient reaction time can be secured. Therefore, it is optimal to prepare a mixture of the catalyst solution (D) and the monofunctional epoxy compound (B) in advance and add it from one point into the extruder.

It is preferable to remove the unreacted monovalent epoxy compound (B) by venting or the like downstream of the position where the monovalent epoxy compound (B) is introduced into the extruder.

As described above, EVOH (A) and monovalent epoxy compound (B) are melt-kneaded in an extruder in the presence of zinc ions (F) as a catalyst, and EVOH (A) and monovalent epoxy compound After (B) is melt-kneaded, the catalyst deactivator (E) is preferably added and further melt-kneaded. If the catalyst is not deactivated, the resulting modified EVOH (C) may have poor thermal stability, which may cause problems in use depending on the application.

The catalyst deactivator (E) used is not particularly limited as long as it reduces the action of the zinc ion (F) acting as a catalyst as a Lewis acid. Metal salts such as alkali metal salts are preferably used. Deactivation of catalysts containing anions of sulfonic acids, which are strong acids, requires the use of alkali metal salts of the anions of acids weaker than the sulfonic acids. This is because the counter ion of the zinc ion (F) constituting the catalyst is exchanged with an anion of a weak acid, resulting in a decrease in the Lewis acidity of the zinc ion (F). The cationic species of the alkali metal salt used for the catalyst deactivator (E) is not particularly limited, and suitable examples include sodium salt, potassium salt and lithium salt. The anion species is also not particularly limited, and carboxylates, phosphates and phosphonates are exemplified as suitable ones.

The use of a salt such as sodium acetate or dipotassium monohydrogen phosphate as the catalyst deactivator (E) improves the thermal stability considerably, but is still insufficient for some applications. The reason for this is thought to be that the zinc ion (F) retains its function as a Lewis acid to some extent and acts as a catalyst for the decomposition and gelation of the modified EVOH (C). As a method for further improving this point, it is preferable to add a chelating agent that strongly coordinates with the zinc ion (F). Such a chelating agent can strongly coordinate with the ions of the metal, so that the Lewis acidity can be almost completely lost, and modified EVOH (C) with excellent thermal stability can be obtained. Further, by using an alkali metal salt as the chelating agent, it is possible to neutralize the sulfonic acid contained in the catalyst as described above.

Suitable chelating agents used as catalyst deactivators (E) include oxycarboxylates, aminocarboxylates, aminophosphonates, and the like. Specifically, examples of the oxycarboxylate include disodium citrate, disodium tartrate, disodium malate, and the like. Aminocarboxylic acid salts include trisodium nitrilotriacetate, disodium ethylenediaminetetraacetic acid, trisodium ethylenediaminetetraacetate, tripotassium ethylenediaminetetraacetate, trisodium diethylenetriaminepentaacetic acid, trisodium 1,2-cyclohexanediaminetetraacetate, ethylenediamine diacetic acid. Monosodium acetate, monosodium N-(hydroxyethyl)iminodiacetate and the like are exemplified. Examples of aminophosphonates include hexasodium nitrilotrismethylenephosphonate, octasodium ethylenediaminetetra(methylenephosphonate), and the like. Among them, polyaminopolycarboxylic acids are preferred, and alkali metal salts of ethylenediaminetetraacetic acid are most suitable in terms of performance and cost.

On the other hand, it has been found that chelating agents such as alkali metal salts of ethylenediaminetetraacetic acid may corrode metals constituting kneading equipment and the like. This time, it was clarified that the reaction between EVOH (A) and monovalent epoxy compound (B) proceeds smoothly even if the amount of zinc ion (F) used as a catalyst is reduced. From the viewpoint of preventing corrosion of the catalyst, it is preferable to use an alkali metal salt of a monocarboxylic acid as the catalyst deactivator (E). The number of carbon atoms in the monocarboxylic acid is preferably 2 to 18, more preferably 6 or less, even more preferably 4 or less. Specifically, acetic acid, propionic acid, and lactic acid are preferred examples. Alkali metal is preferably sodium or potassium.

The amount of the catalyst deactivator (E) added is not particularly limited, but the ratio (E/F) of the number of moles of the catalyst deactivator (E) to the number of moles of zinc ions (F) is 1.5 to 40. It is preferable to If the ratio (E/F) is less than 1.5, the zinc ions (F) may not be sufficiently deactivated, and in the case of melt-kneading for a long time, torque fluctuations are large and melt stability is affected. may have problems. The ratio (E/F) is more preferably 2 or more, more preferably 2.5 or more. On the other hand, if the ratio (E/F) exceeds 40, the resulting modified EVOH (C) may be colored and the production cost may increase. It is preferably 20 or less.

The method of introducing the catalyst deactivator (E) into the extruder is not particularly limited. It is preferable to introduce Considering the solubility of the catalyst deactivator (E) and the influence on the surrounding environment, it is preferable to add it as an aqueous solution.

The catalyst deactivator (E) may be added to the extruder after melt-kneading the EVOH (A) and the monofunctional epoxy compound (B) in the presence of zinc ions (F). However, the EVOH (A) and the monovalent epoxy compound (B) are melt-kneaded in the presence of zinc ions (F), and after removing the unreacted monovalent epoxy compound (B), the catalyst deactivator (E ) is preferably added. As described above, when the catalyst deactivator (E) is added as an aqueous solution, if the catalyst deactivator (E) is added before removing the unreacted monovalent epoxy compound (B), the vent This is because water will be mixed in the monovalent epoxy compound (B) that is removed and recovered for use by e.g., and the separation operation is troublesome. It is also preferable to remove moisture by venting or the like after adding the aqueous solution of the catalyst deactivator (E).

In the production method of the present invention, as a suitable production process when using the catalyst deactivator (E),
(1) melting step of EVOH (A);
(2) addition step of mixture of monovalent epoxy compound (B) and catalyst solution (D);
(3) removal step of unreacted monovalent epoxy compound (B);
(4) addition step of catalyst deactivator (E) aqueous solution;
(5) vacuum removal step of moisture;
The one consisting of each step is exemplified.

As described above, the resin composition obtained by the production method of the present invention includes a modified EVOH (C) containing 0.3 to 40 mol% of the structural unit (I) represented by the formula (I) and zinc ions. (F) is preferably contained, and the content of zinc ion (F) is more preferably 0.05 to 1.0 μmol/g. Here, the zinc ions (F) in the modified EVOH composition are contained as catalyst residues when the catalyst solution (D) is used in the production method described above.

The content of zinc ions (F) in the modified EVOH composition of the present invention is more preferably 0.05 to 1.0 μmol/g. When the content of zinc ions (F) is 1.0 μmol/g or less, even when melt-kneaded for a long period of time, the resin composition exhibits small torque fluctuations and excellent melt stability. The zinc ion (F) content is more preferably 0.9 μmol/g or less. On the other hand, when the zinc ion (F) content is 0.05 μmol/g or more, the reaction between EVOH (A) and the monovalent epoxy compound (B) is promoted. The content of zinc ions (F) is more preferably 0.1 μmol/g or more, still more preferably 0.2 μmol/g or more, and particularly preferably 0.35 μmol/g or more.

Further, the modified EVOH composition of the present invention contains an alkali metal ion (G), and the molar ratio (G/F) of the alkali metal ion (G) to the zinc ion (F) is 5 to 80. preferable. Here, the alkali metal ions are mainly contained as residues when the catalyst deactivator (E) is used in the production method described above. Preferably, said alkali metal ions (G) are sodium ions and/or potassium ions. When the molar ratio (G/F) is 5 or more, the catalyst can be effectively deactivated, and even when melt-kneaded for a long time, the torque fluctuation is small and the melt stability is excellent. It becomes a resin composition. The molar ratio (G/F) is more preferably 6 or more. On the other hand, if the molar ratio (G/F) exceeds 80, the resin composition may turn yellow. The molar ratio (G/F) is more preferably 60 or less, and even more preferably 40 or less.

In the modified EVOH composition of the present invention, at least one selected from the group consisting of alkali metal salts, alkaline earth metal salts, carboxylic acid compounds and phosphoric acid compounds is added by reacting EVOH (A) with epoxy compound (B). It can also be added after the modified EVOH (C) is obtained. In general, in order to improve various physical properties of EVOH such as improvement of adhesion and suppression of coloration, EVOH is optionally selected from the group consisting of alkali metal salts, alkaline earth metal salts, carboxylic acids and phosphoric acid compounds. At least one of the However, as described above, the addition of the various compounds shown above may cause coloration, viscosity reduction, etc. during the reaction between EVOH (A) and epoxy compound (B) in an extruder. Therefore, after the reaction of EVOH (A) with the epoxy compound (B), after removing the remaining epoxy compound (B) by venting, At least one selected from the group is preferably added to the obtained modified EVOH (C). By adopting this addition method, the modified EVOH composition of the present invention can be obtained without causing problems such as coloring and viscosity reduction.

Various additives may be added to the modified EVOH composition of the present invention, if necessary. Examples of such additives include antioxidants, plasticizers, heat stabilizers, UV absorbers, antistatic agents, lubricants, colorants, fillers, or other polymeric compounds, which may be They can be blended as long as the effects of the present invention are not impaired. The total content of polymer compounds other than modified EVOH (C) and various additives may be 10% by mass or less, 5% by mass or less, or 1% by mass or less. .

The modified EVOH composition of the present invention preferably has an oxygen transmission rate of 100 cc·20 μm/m ² ·day·atm or less at 20° C. and 65% RH. The upper limit of the oxygen transmission rate is more preferably 50 cc·20 μm/m ² ·day·atm or less, further preferably 20 cc·20 μm/m ² ·day·atm or less, and 10 cc·20 μm/m ² · It is particularly preferable that it is day·atm or less. Since it is a resin having such a low oxygen transmission rate, the modified EVOH composition of the present invention is suitably used as a barrier material, and is particularly suitably used as a food packaging container.

The modified EVOH composition of the present invention is preferably molded into various molded articles such as films, sheets, containers, pipes, hoses and fibers by melt molding. These moldings can be pulverized and molded again for the purpose of reuse. It is also possible to uniaxially or biaxially stretch films, sheets, fibers and the like. Extrusion molding, melt spinning, injection molding, injection blow molding, and the like can be used as the melt molding method. The melting temperature varies depending on the melting point of the modified EVOH (C) and the like, but is preferably about 120 to 270°C.

The modified EVOH compositions of the invention are preferably used as extrudates. The method for producing the extruded article is not particularly limited, but preferred examples include film extrusion casting, sheet extrusion casting, pipe extrusion, hose extrusion, profile extrusion, extrusion blow molding, and inflation extrusion. . It is also possible to subject the extruded products obtained by these molding methods to secondary processing such as uniaxial or biaxial stretching or thermoforming.

The modified EVOH composition of the present invention can also be put to practical use as a monolayer molding. From the viewpoint of effectively utilizing the modified EVOH composition of the present invention, which is excellent in barrier properties, impact resistance, and flex resistance, films and extrusion blow-molded products (preferably bottles, etc.), flexible packaging containers (preferably flexible tubes or flexible pouches, etc.), pipes, hoses and deformed moldings. As the film, a stretched film is particularly preferable from the viewpoint of taking advantage of the property of the modified EVOH composition of the present invention, which is excellent in stretchability. Among them, a stretched film obtained by stretching twice or more in at least one direction is preferable. Furthermore, it is also preferable to use the stretched film as a heat-shrinkable film.

As described above, the modified EVOH composition of the present invention can be practically used as a single-layer molded product, but it is also preferable to use it as a multi-layer structure containing at least one layer made of the modified EVOH composition. As the layer structure of the multilayer structure, the modified EVOH composition of the present invention, which is often used as a barrier material, is Barrier, the adhesive resin is Ad, the resin other than the barrier material is R, and the scrap recovery layer is Reg. Barrier/R, R/Barrier/R, Barrier/Ad/R, Reg/Barrier/R, R/Ad/Barrier/Ad/R, R/Reg/Ad/Barrier/Ad/Reg/R, etc. Examples include, but are not limited to. When resins other than the modified EVOH composition are provided on both sides of the layer composed of the modified EVOH composition, they may be of different types or may be the same. Additionally, the recovered resin may be blended with resins other than the modified EVOH composition. Each layer may be a single layer, or in some cases may be multiple layers.

Further, a resin composition comprising a modified EVOH (C) containing 0.3 to 40 mol% of the structural unit (I) represented by the formula (I) and an unmodified EVOH or a polyolefin, wherein the modified EVOH A resin composition containing 0.05 to 1.0 μmol/g of zinc ions (F) relative to the mass of (C) is also a preferred embodiment of the present invention. This resin composition can be produced by melt-kneading modified EVOH (C) and unmodified EVOH or polyolefin. As used herein, "unmodified EVOH" means EVOH containing no structural unit (I).

Although the blending ratio of modified EVOH (C) and unmodified EVOH or polyolefin is not particularly limited, it preferably contains 1 to 99% by mass of modified EVOH (C) and 1 to 99% by mass of unmodified EVOH or polyolefin. .

By making a resin composition containing modified EVOH (C) and unmodified EVOH, secondary workability, fatigue resistance, stretchability, or inter-layer Adhesion can be greatly improved. As the unmodified EVOH used here, the same EVOH (A) as the raw material of the modified EVOH (C) can be used. It is appropriately selected depending on the application.

It is preferable that the resin composition comprises 1 to 50% by mass of modified EVOH (C) and 50 to 99% by mass of unmodified EVOH. That is, it is preferable that the unmodified EVOH is the main component and the modified EVOH (C) is the secondary component. By doing so, flexibility and secondary workability can be imparted to the resin composition without significantly impairing the gas barrier properties and transparency inherent in the unmodified EVOH. In addition, the modified EVOH (C) is economically advantageous because the manufacturing cost is higher than that of the unmodified EVOH. More preferably, the content of modified EVOH (C) is 5% by mass or more, and more preferably 10% by mass or more. At this time, the content of unmodified EVOH is more preferably 95% by mass or less, more preferably 90% by mass or less. On the other hand, the content of modified EVOH (C) is more preferably 40% by mass or less, more preferably 30% by mass or less. At this time, the content of unmodified EVOH is more preferably 60% by mass or more, more preferably 70% by mass or more.

A resin composition containing modified EVOH (C) and polyolefin is also preferable. Polyolefin is highly useful because of its excellent mechanical properties and workability and low cost, but its barrier properties are low. By blending the modified EVOH (C) with this, it is possible to improve the barrier property without significantly deteriorating the impact resistance, fatigue resistance, workability, and the like. The polyolefin used here is not particularly limited. For example, polypropylene, polyethylene, ethylene-propylene copolymer and ethylene-vinyl acetate copolymer are preferably used, and polyethylene and polypropylene are particularly preferably used.

It is preferable that the resin composition comprises 10 to 60% by mass of modified EVOH (C) and 40 to 90% by mass of polyolefin. That is, the resin composition preferably contains about half or more of the polyolefin. By doing so, it is possible to impart barrier properties to the resin composition without significantly impairing the inherent mechanical properties and workability of the polyolefin. In addition, modified EVOH (C) is much more expensive to manufacture than polyolefins, so the blending ratio is economically advantageous. More preferably, the modified EVOH (C) content is 20% by mass or more, and the polyolefin content is 80% by mass or less. On the other hand, the content of modified EVOH (C) is more preferably 50% by mass or less, and the content of polyolefin is more preferably 50% by mass or more.

Mixed pellets containing pellets of the modified EVOH composition and pellets of unmodified EVOH or polyolefin are also a preferred embodiment. The mixed pellets are obtained by a step of pelletizing the modified EVOH (C) obtained by the production method of the present invention, and a step of dry blending the obtained modified EVOH (C) pellets and unmodified EVOH or polyolefin pellets. It can be manufactured by a manufacturing method including: According to such a mixed pellet, a molded product of the resin composition can be easily obtained simply by introducing it into a kneading apparatus and melt-molding it.

The resin composition obtained by the production method of the present invention and its use have been described above. The resin composition thus obtained contains a novel resin composition containing a highly modified EVOH with a low catalyst residue content. That is, another aspect of the present invention is a modified ethylene-vinyl alcohol copolymer (C) containing 2 to 40 mol% of a structural unit (I) represented by the following formula (I) and a zinc ion (F). and a zinc ion (F) content of 0.05 to 1.0 μmol/g.

(In formula (I), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an alicyclic carbonized group having 3 to 6 carbon atoms. represents a hydrogen group or a phenyl group, and the aliphatic hydrocarbon group, alicyclic hydrocarbon group and phenyl group may have a hydroxyl group, an alkoxy group, a carboxyl group or a halogen atom, and R ³ and R ⁴ are may be combined).

The method for producing this resin composition is not particularly limited. In addition, except that the content of the structural unit (I) is 2 mol % or more, the above descriptions of the resin composition obtained by the production method of the present invention and its use apply.

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these. Analysis of EVOH (A) and modified EVOH (C) was performed according to the following method.

(1) Ethylene content and saponification degree of EVOH (A) ¹ H-NMR (nuclear magnetic resonance) measurement using deuterated dimethyl sulfoxide as a solvent (using "JNM-GX-500 type" manufactured by JEOL Ltd.) It was calculated from the spectrum obtained by

(2) Intrinsic viscosity of EVOH (A) 0.20 g of dry pellets made of dried EVOH (A) to be used as a sample was precisely weighed, and added to 40 ml of hydrous phenol (water/phenol = 15/85: mass ratio) at 60°C. The mixture was heated and dissolved at 30° C. for 3 to 4 hours, measured with an Ostwald viscometer (t0=90 seconds), and the intrinsic viscosity [η] was obtained from 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 the blank (water-containing phenol) to pass through the viscometer t: time for the water-containing phenol solution in which the sample is dissolved to pass through the viscometer

(3) Quantification of acetic acid content in EVOH (A) 20 g of dry pellets of EVOH (A) to be used as a sample were added to 100 ml of ion-exchanged water and heated and extracted at 95°C for 6 hours. The extract was subjected to neutralization titration with 1/50 N NaOH using phenolphthalein as an indicator to determine the content of acetic acid.

(4) Determination of Na ions, K ions, Mg ions, and Ca ions in EVOH (A) and modified EVOH (C) 10 g of dry pellets of EVOH (A) or modified EVOH (C) used as samples are 0.01 normal. and stirred at 95° C. for 6 hours. The aqueous solution after stirring was quantitatively analyzed using ion chromatography to quantify the amounts of Na, K, Mg and Ca ions. The column used was ICS-C25 manufactured by Yokogawa Electric Corporation, and the eluent was an aqueous solution containing 5.0 mM tartaric acid and 1.0 mM 2,6-pyridinedicarboxylic acid. For quantitative determination, calibration curves prepared with an aqueous sodium chloride solution, an aqueous potassium chloride solution, an aqueous magnesium chloride solution, and an aqueous calcium chloride solution were used.

(5) Determination of Phosphate Ions in EVOH (A) and Modified EVOH (C) 10 g of dry pellets of EVOH (A) or modified EVOH (C) to be used as a sample were put into 50 ml of a 0.01N hydrochloric acid aqueous solution, Stir at 95° C. for 6 hours. The aqueous solution after stirring was quantitatively analyzed using ion chromatography to quantify the amount of phosphate ions. The column used was ICS-A23 manufactured by Yokogawa Electric Corporation, and the eluent was an aqueous solution containing 2.5 mM sodium carbonate and 1.0 mM sodium bicarbonate. A calibration curve prepared with an aqueous solution of sodium dihydrogen phosphate was used for quantification.

(6) Quantification of Zinc Ions (F) in Modified EVOH (C) 10 g of dry pellets of modified EVOH (C) to be used as a sample were added to 50 ml of 0.01N hydrochloric acid aqueous solution and stirred at 95° C. for 6 hours. The aqueous solution after stirring was analyzed by ICP emission spectrometry. Optima 4300DV manufactured by PerkinElmer was used as an apparatus. A measurement wavelength of 206.20 nm was used in the measurement of zinc ions. For quantification, a calibration curve prepared using a commercially available zinc standard solution was used.

(7) Melting points of EVOH (A) and modified EVOH (C) The melting points of EVOH (A) and modified EVOH (C) were measured using a differential scanning calorimeter (DSC) RDC220/SSC5200H type manufactured by Seiko Electronics Industry Co., Ltd. It was measured based on JIS K7121. However, indium and lead were used for temperature calibration.

Example 1
Ethylene content 32 mol%, degree of saponification 99.6 mol%, water-containing pellets made of ethylene-vinyl alcohol copolymer having an intrinsic viscosity of 0.0882 L / g (water content: 130% (dry base): 57% (wet 100 parts by mass of Base)) was immersed in 370 parts by mass of an aqueous solution containing 0.1 g/L of acetic acid and 0.044 g/L of potassium dihydrogen phosphate at 25° C. for 6 hours with stirring. The obtained pellets were dried at 105° C. for 20 hours to obtain dry EVOH pellets. The dry EVOH pellets have a potassium content of 8 ppm (converted to metal element), an acetic acid content of 53 ppm, a phosphate compound content of 20 ppm (converted to phosphate radical), and an alkaline earth metal salt (Mg salt or Ca salt). The content was 0 ppm. Moreover, the MFR of the dried pellets was 8 g/10 minutes (190° C., under 2160 g load). The EVOH pellets thus obtained were used as EVOH (A). Epoxypropane was used as the monovalent epoxy compound (B). A solution containing 3.3% by mass of zinc trifluoromethanesulfonate, 0.6% by mass of methanol, and 96.0% by mass of acetone was used as the catalyst solution (D).

A TEM-35BS extruder (37 mmφ, L/D=52.5) manufactured by Toshiba Machine Co., Ltd. was used, and a screw configuration and vents and injection ports were installed as shown in FIG. Barrel C1 was cooled with water, barrels C2 to C15 were set at 200° C., and operated at a screw speed of 250 rpm. The above EVOH (A) pellets were added from the resin feed port of C1 at a rate of 11 kg / hr, the internal pressure of the vent 1 was reduced to 60 mmHg, and epoxy propane was added from the injection port 1 of C8 at a rate of 1.5 kg / hr. The catalyst solution (D) was mixed and then fed so that the catalyst solution (D) was added at a rate of 0.07 kg/hr (pressure during feeding: 3 MPa). Next, after removing unreacted epoxypropane from the vent 2 at normal pressure, an 8.2% by mass aqueous solution of ethylenediaminetetraacetic acid trisodium trihydrate (EDTA) as a catalyst deactivator (E) was added to C13. It was added from injection port 2 at a rate of 0.11 kg/hr.

In the melt-kneading operation, the mixing ratio of the monovalent epoxy compound (B) was 13.6 parts by mass with respect to 100 parts by mass of EVOH (A). Catalyst solution (D) was added at 0.57 μmol/g in moles of zinc ions (F) relative to the mass of EVOH (A). The molar ratio (E/F) of the catalyst deactivator (E) to the zinc ions (F) contained in the catalyst solution (D) was 3.5.

The vent 3 was evacuated to an internal pressure of 20 mmHg to remove moisture to obtain modified EVOH (C). The resulting modified EVOH (C) had an MFR of 7 g/10 min (190°C, under a load of 2160 g) and a melting point of 132°C. The content of zinc ions is 35 ppm (0.54 μmol/g), and the content of alkali metal ions (G) is 138 ppm (5.9 μmol/g) in terms of metal elements [sodium: 130 ppm (5.7 μmol/g ), potassium: 8 ppm (0.2 μmol/g)]. Also, the alkaline earth metal salt (Mg salt or Ca salt) content was 0 ppm. The alkaline earth metal salt content was 0 ppm also in other examples and comparative examples of the present application. The molar ratio (G/F) of alkali metal ions (G) to zinc ions (F) was 10.9. The number of moles of sulfonate ions contained is twice the number of moles of zinc ions (F), and this is the same for Examples 2-11.

The chemical structure of the modified EVOH (C) modified with epoxypropane thus obtained was determined by performing NMR measurement after trifluoroacetylating the modified EVOH (C) according to the procedure described in Patent Document 1. . As a result, the modified EVOH (C) had an ethylene content of 32 mol% and a structural unit (I) content of 5.5 mol%.

(a) Preparation of monolayer film Using the modified EVOH (C) thus obtained, a film forming machine consisting of a 40φ extruder (PLABOR GT-40-A manufactured by Plastics Engineering Laboratory) and a T-die is used to produce the following A film was formed under extrusion conditions to obtain a single layer film having a thickness of 25 μm.
Type: Single-screw extruder (non-vented type)
L/D: 24
Diameter: 40mmφ
Screw: single full flight type, surface nitriding steel Screw rotation speed: 40 rpm
Die: 550 mm wide coat hanger die Lip gap: 0.3 mm
Cylinder and die temperature settings:
C1/C2/C3/Adapter/Die
= 180/200/210/210/210 (°C)

Using the monolayer film produced as described above, the oxygen permeation rate and haze were measured according to the methods shown in (b) to (d) below, and a bending resistance test was performed.

(b) Measurement of Oxygen Permeation Rate The monolayer film prepared above was conditioned at 20° C.-65% RH for 5 days. Using two humidity-conditioned monolayer film samples, MOCON OX-TRAN 2/20 type manufactured by Modern Control Co., Ltd., under conditions of 20 ° C.-65% RH, according to the method described in JIS K7126 (isobaric method). The oxygen permeation rate was measured according to the above, and the average value was obtained. The oxygen transmission rate was 1.5 cc·20 μm/m ² ·day·atm, indicating good barrier properties.

(c) Measurement of Haze Using the monolayer film prepared above, the integral formula H.O. T. Haze was measured according to JIS D8741 using an R meter. The haze was 0.1%, showing very good transparency.

(d) Evaluation of bending resistance 50 sheets of the above-prepared single-layer film cut to 21 cm × 30 cm were produced, and each film was conditioned at 20 ° C.-65% RH for 5 days, and then subjected to ASTM F 392- 74, using a gelbo flex tester manufactured by Rigaku Kogyo Co., Ltd., bending times 50 times, 75 times, 100 times, 125 times, 150 times, 175 times, 200 times, 225 times, 250 times, 300 times After bending, the number of pinholes was measured. Measurement was performed 5 times for each bending number, and the average value was taken as the number of pinholes. Taking the number of bending times (P) on the horizontal axis and the number of pinholes (N) on the vertical axis, plotting the above measurement results, the number of bending times (Np1) when the number of pinholes is 1 is obtained by extrapolation, and effective 2 digit number. As a result, Np1 was 160 times, indicating extremely excellent flex resistance.

(e) Evaluation of stretchability Next, using the obtained modified EVOH (C), a multi-layer sheet (ionomer resin layer/adhesive resin layer /modified EVOH (C) layer/adhesive resin layer/ionomer resin layer). The composition of the sheet consists of two outermost layers of ionomer resin (“Himilan 1652” manufactured by Mitsui DuPont Polychemicals) each having a thickness of 250 μm, an adhesive resin (“Admer NF500” manufactured by Mitsui Chemicals) each having a thickness of 30 μm, and a modified EVOH (C ) layer is 90 μm.

Co-extrusion conditions are as follows.
Layer structure:
Ionomer resin/adhesive resin/modified EVOH (C)/adhesive resin/ionomer resin (thickness 250/30/90/30/250: unit is μm)
Extrusion temperature for each resin:
C1/C2/C3/die=170/170/220/220°C
Extruder specifications for each resin:
ionomer resin;
32φ extruder GT-32-A type (manufactured by Plastic Engineering Laboratory Co., Ltd.)
adhesive resin;
25φ extruder P25-18AC (manufactured by Osaka Seiki Kogyo Co., Ltd.)
modified EVOH (C);
20φ Extruder Lab machine ME type CO-EXT (manufactured by Toyo Seiki Co., Ltd.)
T-die specifications:
3 types, 5 layers, 300 mm width (manufactured by Plastic Engineering Laboratory Co., Ltd.)
Cooling roll temperature: 50°C
Take-up speed: 4m/min

The resulting multilayer sheet was subjected to simultaneous biaxial stretching at 60° C. at a stretching ratio of 4×4 times using a pantograph type biaxial stretching machine manufactured by Toyo Seiki Co., Ltd.
The film appearance after stretching was evaluated according to the following evaluation criteria.
Judgment: Criteria A: No unevenness and local uneven thickness.
B: There is slight unevenness, but there is no local uneven thickness.
C: Slight nonuniformity and slight local unevenness in thickness, but bearable for practical use.
D: Significant unevenness and large local uneven thickness.
E: The film was torn.
The stretched film of this example had neither unevenness nor local unevenness in thickness, and was evaluated as A.

(f) Evaluation of torque stability during long-term operation Using the obtained modified EVOH (C), a melt-kneading test was carried out in order to evaluate stability during long-term operation. Torque when a 60 g sample of modified EVOH (C) was melted and kneaded under nitrogen atmosphere at 230° C. and 100 rpm using Labo Plastomill (manufactured by Toyo Seiki: 4C150 type, R-60 type, biaxially opposite direction). change was measured. The kneading time was 180 minutes, and the difference ΔT between the initial torque value T0 at the start of kneading and the minimum torque value Tmin during the kneading time was evaluated. The minimum value Tmin correlates with the degree of decomposition of the resin under high temperature shear, and the smaller ΔT, the higher the long-term operational stability during melt molding of the resin. ΔT of the modified EVOH (C) obtained in this example was 0.3 (kgf·m).

(g) Interlayer adhesion test Obtained modified EVOH (C), polyethylene resin ("Novatec LD LJ400" manufactured by Japan Polyethylene Co., Ltd.: low density polyethylene, melting point 108 ° C.), and adhesive resin (manufactured by Mitsui Chemicals, Inc. " Admer NF518": maleic anhydride graft-modified linear low-density polyethylene, melting point 120 ° C.), 3 types of 5-layer unstretched multilayer film (polyethylene/adhesive resin/modified EVOH (C)/adhesive resin/polyethylene = 144 µm/18 µm/18 µm/18 µm/144 µm). The thickness of the coextruded film was adjusted by appropriately changing the screw rotation speed and take-up roll speed. The extruder, extrusion conditions, and the die used were as follows.

- Modified EVOH (C):
Extruder: Single-screw extruder (Toyo Seiki Co., Ltd. Laboki ME type CO-EXT)
Screw: diameter 20 mmφ, L/D20, full-flight screw Extrusion temperature: feed section/compression section/measuring section/die = 175/200/220/220°C
・ Adhesive resin Extruder: Single screw extruder (Technobell Co., Ltd. SZW20GT-20MG-STD)
Screw: diameter 20 mmφ, L/D20, full-flight screw Extrusion temperature: feed section/compression section/measuring section/die = 175/200/220/220°C
・Polyethylene resin Extruder: Single screw extruder (Plastic Engineering Laboratory GT-32-A)
Screw: caliber 32 mmφ, L/D28, full-flight screw Extrusion temperature: feeding section/compression section/measuring section/die = 175/200/220/220°C
・ Die Coat hanger die for 3 types of 5 layers with a width of 300 mm (manufactured by Plastic Engineering Laboratory Co., Ltd.), die temperature 220 ° C.

After conditioning the multilayer structure obtained as described above at 23 ° C. and 50% RH, a sample with a length of 150 mm and a width of 15 mm was cut along the extrusion direction. -50M type tensile tester”, the peel strength was measured when peeled in the T-type peel mode at a tensile speed of 250 mm / min in an atmosphere of 23 ° C. and 50% RH, and was judged according to the following criteria. By the way, the evaluation was A. However, the peeling interface is the interface between the modified EVOH (C) layer and the adhesive resin layer.
Judgment: Criteria A: 250g/15mm or more B: 100g/15mm or more and less than 250g/15mm C: Less than 100g/15mm

(h) Yellowness index of resin composition pellets The yellowness index (YI) of the obtained resin composition pellets was measured using a spectrophotometer ("LabScan XE Sensor" manufactured by HunterLab) and judged according to the following criteria. was evaluated as A. The YI value is an index representing the yellowness of an object, and the higher the YI value, the stronger the yellowness, while the lower the YI value, the weaker the yellowness and less coloring.
Judgment: Criteria A: Less than 15 B: 15 or more and less than 25 C: 25 or more and less than 35 D: 35 or more and less than 45 E: 45 or more

The production method of the modified EVOH (C) is summarized in Table 1, the composition is summarized in Table 2, and the evaluation results of the film and resin are summarized in Table 3, respectively.

Example 2
As raw material EVOH pellets, EVOH with an ethylene content of 44 mol%, a degree of saponification of 99.8 mol%, an intrinsic viscosity of 0.096 L/g, and an MFR of 5 g/10 minutes (190°C, under a load of 2160 g) {acetic acid content of 53 ppm , a sodium content of 1 ppm (converted to metal element), a potassium content of 8 ppm (converted to metal element), and a phosphoric acid compound content of 20 ppm (converted to phosphate radical)} were placed in a polyethylene bag. Subsequently, 395 g of the same catalyst solution (D) as in Example 1 was added to the EVOH in the bag. The EVOH to which the catalyst solution was added as described above was heated at 50° C. for 10 hours with the mouth of the bag closed while occasionally shaking to impregnate the EVOH with the catalyst solution (D). The obtained EVOH was vacuum-dried at 30° C. to obtain EVOH pellets containing zinc ions (F) and sulfonate ions.

As EVOH (A), a pellet mixture obtained by dry-blending 10 parts by mass of EVOH pellets containing zinc ions and sulfonate ions with 90 parts by mass of the raw material EVOH pellets was used. Also, 1,2-epoxybutane was used as the monovalent epoxy compound (B).

A TEM-35BS extruder (37 mmφ, L/D=52.5) manufactured by Toshiba Machine Co., Ltd. was used, and a screw configuration and vents and injection ports were installed as shown in FIG. Barrel C1 was water-cooled, barrels C2-C3 were set at 200° C., and barrels C4-C15 were set at 220° C., and the operation was performed at a screw speed of 200 rpm. From the resin feed port of C1, the pellet mixture was fed as EVOH (A) at a rate of 11 kg / hr, the internal pressure of the vent 1 was reduced to 60 mmHg, and epoxybutane was fed from the injection port 1 of C8 at a rate of 2.5 kg / hr. was fed (pressure during feeding: 3.5 MPa). The vent 2 was evacuated to an internal pressure of 200 mmHg to remove unreacted epoxybutane, and an 8.2% by mass aqueous solution of trisodium ethylenediaminetetraacetate trihydrate was added at a rate of 0.14 kg/hr from the injection port 2 of C13. .

The mixing ratio of the monovalent epoxy compound (B) in the melt-kneading operation was 22.7 parts by mass with respect to 100 parts by mass of EVOH (A). Zinc ions (F) were added at 0.78 μmol/g in moles relative to the mass of EVOH (A). The molar ratio (E/F) of the catalyst deactivator (E) to the zinc ions (F) was 3.3.

The vent 3 was evacuated to an internal pressure of 20 mmHg to remove moisture to obtain modified EVOH (C). The modified EVOH (C) had an MFR of 5 g/10 minutes (190°C, under a load of 2160 g) and a melting point of 109°C. In addition, the zinc ion (F) content is 46 ppm (0.70 μmol/g), and the alkali metal salt content is 168 ppm (7.1 μmol/g) in terms of metal element [sodium: 160 ppm (6.9 μmol/g ), potassium: 8 ppm (0.2 μmol/g)].

The chemical structure of the modified EVOH (C) modified with epoxybutane obtained in this manner was obtained by trifluoroacetylation of the modified EVOH (C) according to the procedure described in Patent Document 1 and then performing NMR measurement. rice field. As a result, the modified EVOH (C) prepared in Example 2 had an ethylene content of 44 mol % and a structural unit (I) content of 7.0 mol %.

Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Example 3
In Example 2, as raw material EVOH pellets, EVOH { Using pellets with an acetic acid content of 53 ppm, a sodium content of 11 ppm (converted to metal element), a potassium content of 8 ppm (converted to metal element), and a phosphoric acid compound content of 20 ppm (converted to phosphate group)}, a catalyst deactivator (E) A modified EVOH (C) was obtained in the same manner as in Example 2, except that the addition rate of the solution was changed to 0.15 kg/hr. Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Example 4
A modified EVOH (C) was obtained in the same manner as in Example 1, except that the addition rate of the catalyst solution (D) was changed to 0.11 kg/hr. Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Example 5
A modified EVOH (C) was obtained in the same manner as in Example 1, except that the addition rate of the catalyst solution (D) was changed to 0.04 kg/hr. Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Example 6
A modified EVOH (C) was obtained in the same manner as in Example 1, except that the addition rate of the catalyst deactivator (E) solution was changed to 0.22 kg/hr. Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Example 7
Example 1 was repeated except that the addition rate of the catalyst solution (D) was changed to 0.04 kg/hr and the addition rate of the catalyst deactivator (E) solution was changed to 0.32 kg/hr. to obtain modified EVOH (C). Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Example 8
Ethylene content 32 mol%, degree of saponification 99.6 mol%, water-containing pellets made of ethylene-vinyl alcohol copolymer having an intrinsic viscosity of 0.0882 L / g (water content: 130% (dry base): 57% (wet Base))) was immersed and stirred in 370 parts by mass of an aqueous solution containing 0.1 g/L of acetic acid and 0.88 g/L of potassium dihydrogen phosphate at 25°C for 6 hours. The obtained pellets were dried at 105° C. for 20 hours to obtain dry EVOH pellets. The dry EVOH pellets have a potassium content of 160 ppm (converted to metal element), an acetic acid content of 53 ppm, a phosphate compound content of 400 ppm (converted to phosphate radical), and an alkaline earth metal salt (Mg salt or Ca salt). The content was 0 ppm.

Modified EVOH (C) was obtained in the same manner as in Example 1 except that the dried EVOH pellets thus obtained were used as EVOH (A). Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Example 9
Ethylene content 32 mol%, degree of saponification 99.6 mol%, water-containing pellets made of ethylene-vinyl alcohol copolymer having an intrinsic viscosity of 0.0882 L / g (water content: 130% (dry base): 57% (wet 100 parts by mass of Base)) was immersed in 370 parts by mass of an aqueous solution containing 0.1 g/L of acetic acid and 0.022 g/L of potassium dihydrogen phosphate at 25° C. for 6 hours with stirring. The obtained pellets were dried at 105° C. for 20 hours to obtain dry EVOH pellets. The dry EVOH pellets have a potassium content of 4 ppm (converted to metal element), an acetic acid content of 53 ppm, a phosphate compound content of 10 ppm (converted to phosphate radical), and an alkaline earth metal salt (Mg salt or Ca salt). The content was 0 ppm.

The dry EVOH pellets thus obtained were used as EVOH (A), the addition rate of the catalyst solution (D) was changed to 0.11 kg/hr, and the addition rate of the catalyst deactivator (E) solution was changed to 0.08 kg/hr. A modified EVOH (C) was obtained in the same manner as in Example 1, except that it was changed. Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Example 10
A modified EVOH (C) was obtained in the same manner as in Example 1, except that the addition rate of the catalyst solution (D) was changed to 0.01 kg/hr. Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Example 11
Modified EVOH (C) was obtained in the same manner as in Example 1, except that the catalyst deactivator (E) was changed to a 4.9% by mass aqueous solution of sodium acetate. Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Comparative example 1
28 parts by mass of zinc acetylacetonate monohydrate was mixed with 957 parts by mass of 1,2-dimethoxyethane to obtain a mixed solution. 15 parts by mass of trifluoromethanesulfonic acid was added to the obtained mixture while stirring to obtain a catalyst solution (D). The catalyst solution (D) contains 1 mol of trifluoromethanesulfonic acid per 1 mol of zinc acetylacetonate monohydrate.

A modified EVOH (C) was obtained in the same manner as in Example 1, except that the catalyst solution (D) was added at a rate of 0.22 kg/hr. Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3. Although the amount of zinc ions (F) contained in modified EVOH (C) was three times or more that of Example 1, the content of structural units (I) was the same as in Example 1. From this, it can be seen that a large amount of zinc ions (F) were required as compared with the examples. The number of moles of sulfonate ions contained in modified EVOH (C) was one times the number of moles of zinc ions (F).

Comparative example 2
5 kg of the same raw material pellets as in Example 2 were placed in a polyethylene bag. Subsequently, a catalyst solution (D) prepared by dissolving 27.44 g (0.125 mol) of zinc acetate dihydrate and 15 g (0.1 mol) of trifluoromethanesulfonic acid in 500 g of water was added to the EVOH in the bag. The EVOH to which the catalyst solution had been added as described above was heated at 90° C. for 5 hours with the mouth of the bag closed while occasionally shaking to impregnate the EVOH with the catalyst solution (D). The obtained EVOH was vacuum-dried at 90° C. to obtain EVOH pellets containing zinc ions (F) and sulfonate ions.

As EVOH (A), a pellet mixture obtained by dry-blending 10 parts by mass of EVOH pellets containing zinc ions and sulfonate ions with 90 parts by mass of the raw material EVOH pellets was used. A modified EVOH (C) was obtained in the same manner as in Example 2 except that the EVOH (A) thus obtained was used. Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3. The number of moles of sulfonate ions contained in modified EVOH (C) was 0.8 times the number of moles of zinc ions (F).

Comparative example 3
In Example 1, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1 using dry EVOH pellets before being fed into the extruder. The results are summarized in Tables 1-3. The flex resistance was measured by bending 25 times, 30 times, 35 times, 40 times, 50 times, 60 times, 80 times and 100 times.

Comparative example 4
In Example 2, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1 using raw EVOH pellets before being impregnated with the catalyst solution (D). The results are summarized in Tables 1-3. The flex resistance was measured in the same manner as in Comparative Example 3.

Comparative example 5
A modified EVOH (C) was obtained in the same manner as in Example 1, except that the feeding of the catalyst solution (D) and the catalyst deactivator (E) was stopped. Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Comparative example 6
In Example 2, instead of using a pellet mixture obtained by dry-blending EVOH pellets containing zinc ions and sulfonate ions with raw EVOH pellets, only raw EVOH pellets were used, and the feed of the catalyst deactivator (E) was stopped. Modified EVOH (C) was obtained in the same manner as in Example 1 except that Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Comparative example 7
A modified EVOH (C) was obtained in the same manner as in Comparative Example 1, except that the catalyst solution (D) was added at a rate of 0.06 kg/hr. Using the modified EVOH (C) thus obtained, a single layer film and a multilayer film were produced and evaluated in the same manner as in Example 1. The results are summarized in Tables 1-3.

Example 12
・Production of resin composition pellets Ethylene content 32 mol%, saponification degree 99.9 mol%, melt flow rate (190 ° C., under 2160 g load) 1.6 g / 10 minutes, melting point 183 ° C. Unmodified EVOH 80 parts by mass , and 20 parts by mass of the modified EVOH (C) obtained in Example 1 were dry-blended to obtain mixed pellets. Using a 30mmφ twin-screw extruder (Japan Steel Works, Ltd. TEX-30SS-30CRW-2V), the mixed pellets are extruded and pelletized under the conditions of a barrel temperature of 200 ° C., a screw rotation speed of 300 rpm, and an extruded resin amount of 25 kg / hour. After that, hot air drying was performed at 80° C. for 16 hours to obtain resin composition pellets. The phosphoric acid compound content (in terms of phosphate root), acetic acid content and Na ion content (in terms of metal element) of the obtained resin composition were measured and found to be 40 ppm, 250 ppm and 160 ppm, respectively. The melt flow rate of the resin composition (190° C., under 2160 g load) was 1.9 g/10 minutes.

Measurement of Oxygen Permeation Rate Using the resin composition thus obtained, a monolayer film having a thickness of 25 μm was obtained in the same manner as in Example 1(a). Using the obtained single-layer film, the oxygen transmission rate was measured in the same manner as in Example ¹ (b). showed sex.

- Measurement of Young's modulus The monolayer film was conditioned in an atmosphere of 23°C and 50% RH for 7 days, and then cut into strips with a width of 15 mm. Using the film sample, Young's modulus was measured with an Autograph AGS-H manufactured by Shimadzu Corporation under the conditions of a chuck interval of 50 mm and a tensile speed of 5 mm/min. Ten samples were measured, and the average value was obtained. Young's modulus was 180 kgf/mm ² .

Measurement of Tensile Yield Strength and Tensile Elongation at Break The monolayer film was conditioned in an atmosphere of 23° C. and 50% RH for 7 days, and then cut into strips with a width of 15 mm. Using this film sample, the tensile strength at yield and tensile elongation at break were measured with an Autograph AGS-H manufactured by Shimadzu Corporation under the conditions of a chuck interval of 50 mm and a tensile speed of 500 mm/min. Ten samples were measured, and the average value was obtained. The tensile strength at yield and tensile elongation at break were 6.5 kgf/mm ² and 310%, respectively.

- Measurement of haze Using the single-layer film, haze was measured in the same manner as in Example 1 (c). The haze was 0.1%, showing very good transparency.

-Evaluation of bending resistance Using the single-layer film, bending resistance was evaluated in the same manner as in Example 1 (d). As a result, Np1 was 90 times, indicating excellent flex resistance.

・Evaluation of stretchability of single-layer film The single-layer film is subjected to a pantograph type biaxial stretching device manufactured by Toyo Seiki, and the range of stretching ratio is 2.0 × 2.0 times to 5.0 × 5.0 times at 100 ° C. Simultaneous biaxial stretching was carried out while changing the magnification by 0.25×0.25 times. The maximum draw ratio at which good drawing was possible without causing breakage was 4.0×4.0 times, and the drawn film had no unevenness or local deviation in thickness.

Interlayer adhesion test Using the obtained resin composition, a multilayer film was obtained in the same manner as in (g) of Example 1, and then the peel strength was measured.

Claims (15)

Using a catalyst solution (D) which is an acetone solution containing zinc ions (F) and sulfonate ions, an ethylene-vinyl alcohol copolymer (A) and a monovalent epoxy compound (B) having 2 to 8 carbon atoms are reacted. A method for producing a modified ethylene-vinyl alcohol copolymer (C), wherein the reaction is performed by melt-kneading in an extruder. An ethylene-vinyl alcohol copolymer (A), a monovalent epoxy compound (B), and a catalyst solution (D) are introduced into an extruder and melt-kneaded in the extruder to obtain an ethylene-vinyl alcohol copolymer. 2. The method for producing the modified ethylene-vinyl alcohol copolymer (C) according to claim 1, wherein the polymer (A) and the monovalent epoxy compound (B) are reacted. 3. The modified ethylene-vinyl alcohol copolymer according to claim 2, wherein a mixture of the monovalent epoxy compound (B) and the catalyst solution (D) is added to the molten ethylene-vinyl alcohol copolymer (A). (C) manufacturing method. The ethylene-vinyl alcohol copolymer (A) is impregnated with the catalyst solution (D), introduced into an extruder, and melt-kneaded with the monofunctional epoxy compound (B) in the extruder to obtain ethylene-vinyl alcohol. 2. The method for producing a modified ethylene-vinyl alcohol copolymer (C) according to claim 1, wherein the alcohol copolymer (A) and the monovalent epoxy compound (B) are reacted. The modified ethylene-vinyl alcohol copolymer according to any one of claims 1 to 4, wherein the ethylene-vinyl alcohol copolymer (A) has an ethylene content of 5 to 55 mol% and a degree of saponification of 90 mol% or more. Manufacturing method of union (C). The modified ethylene-vinyl alcohol copolymer according to any one of claims 1 to 4 , wherein 1 to 50 parts by mass of the monovalent epoxy compound (B) is melt-kneaded with 100 parts by mass of the ethylene-vinyl alcohol copolymer (A). A method for producing the polymer (C). Modified ethylene-vinyl alcohol according to any one of claims 1 to 4 , wherein zinc ions (F) are used in an amount of 0.05 to 1.0 μmol/g in moles relative to the mass of the ethylene-vinyl alcohol copolymer (A). A method for producing a copolymer (C). 5. Any one of claims 1 to 4 , wherein after the ethylene-vinyl alcohol copolymer (A) and the monovalent epoxy compound (B) are melt-kneaded, the catalyst deactivator (E) is added and further melt-kneaded. A method for producing the modified ethylene-vinyl alcohol copolymer (C) described. 9. The method for producing a modified ethylene-vinyl alcohol copolymer (C) according to claim 8, wherein the catalyst deactivator (E) is a chelating agent. 9. The method for producing a modified ethylene-vinyl alcohol copolymer (C) according to claim 8, wherein the catalyst deactivator (E) is a metal salt. Modification according to claim 8 , wherein the ratio (E/F) of the number of moles of the catalyst deactivator (E) to the number of moles of zinc ions (F) contained in the catalyst solution (D) is 1.5 to 40. A method for producing an ethylene-vinyl alcohol copolymer (C). The ethylene-vinyl alcohol copolymer (A) and the monovalent epoxy compound (B) are melt-kneaded, and after removing the unreacted monovalent epoxy compound (B), the catalyst deactivator (E) is added. 9. A method for producing the modified ethylene-vinyl alcohol copolymer (C) according to 8 . Modification according to any one of claims 1 to 4 , wherein the modified ethylene-vinyl alcohol copolymer (C) contains 0.3 to 40 mol% of a structural unit (I) represented by the following formula (I) A method for producing an ethylene-vinyl alcohol copolymer (C).

(In formula (I), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an alicyclic carbonized group having 3 to 6 carbon atoms. represents a hydrogen group or a phenyl group, and the aliphatic hydrocarbon group, alicyclic hydrocarbon group and phenyl group may have a hydroxyl group, an alkoxy group, a carboxyl group or a halogen atom, and R ³ and R ⁴ are may be combined). A step of melt-kneading the modified ethylene-vinyl alcohol copolymer (C) obtained by the production method according to any one of claims 1 to 4 and an unmodified ethylene-vinyl alcohol copolymer or polyolefin, A method for producing a resin composition. A step of pelletizing the modified ethylene-vinyl alcohol copolymer (C) obtained by the production method according to any one of claims 1 to 4 , and pellets of the obtained modified ethylene-vinyl alcohol copolymer (C). and unmodified ethylene-vinyl alcohol copolymer or polyolefin pellets.

Images