JP2002284886A - Manufacturing method of ethylene/vinyl alcohol copolymer resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently and stably manufacturing various kinds of ethylene/vinyl alcohol copolymers (EVOH's) each in a small quantity so as to cope with diversification of uses of the EVOH's. SOLUTION: An EVOH (component A) having a water content of 5-40 wt.% extruded from a first extruder and an additive component (component B) are introduced into a second extruder, molten and kneaded and then delivered. Another component (component C) can be further introduced into the first extruder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ethylene-vinyl alcohol copolymer (hereinafter abbreviated as "EVOH").
The present invention relates to a method for producing a resin composition.

[0002]

2. Description of the Related Art EVOH has a gas barrier property, oil resistance,
Excellent in fragrance retention and transparency. By utilizing this property, EVOH is formed into films, sheets, bottles, and the like, and is used for food packaging and the like.

[0003] Conventionally, various components other than EVOH are blended to improve various characteristics of EVOH. It has also been proposed to mix various components with EVOH in an extruder. For example, JP-A-5-93092 describes a method for improving the dispersibility of starch by mixing starch and EVOH in a molten state. In the embodiment described in the publication, a mixture of starch and glycerin is fed to a twin screw extruder to produce
EVOH heated and melted at 70 ° C. and heated and melted at 210 ° C. by a single screw extruder is supplied from a side supply port of the twin screw extruder, and both are kneaded in the twin screw extruder.

When dry EVOH is introduced into an extruder, it needs to be melted at a high temperature as described above. In the method disclosed in JP-A-5-9334, EVOH in a water-containing state is used. According to the publication, EVOH pellets having a water content of 20 to 60% by weight and raw starch (corn starch having a water content of 12%) are charged into a Henschel mixer and mixed, and this mixture is supplied to a twin-screw extruder equipped with a vent. And kneading at 120 ° C., melt-extrusion into strands, and pelletizing the strand-like solid using a pelletizer.

[0005]

With the diversification of the use of EVOH, the EVOH production line is usually manufactured with a special brand in which necessary additives are further blended as needed without reducing the productivity while producing a brand. It is required to produce brands. As described above, a kneading method in consideration of the characteristics of the components to be blended has been conventionally studied. However, a kneading method suitable for a request for small-quantity multi-product production has not yet been proposed.

[0006] Accordingly, the present invention provides an EVOH of a small quantity and a large variety.
An object is to provide a method suitable for producing a resin composition.

[0007]

In order to achieve the above-mentioned object, a method for producing an EVOH resin composition according to the present invention comprises a method for producing ethylene-vinyl resin having a water content of 5 to 40% by weight extruded from a first extruder. At least a part of the alcohol copolymer resin (component A) and the additional component (component B) are introduced into a second extruder, melt-kneaded, and then discharged.

According to the present invention, E
Since the water content of VOH is adjusted to 5 to 40% by weight,
EVOH obtained from the first extruder can be stabilized (for example, strand foaming and frequent occurrence of strand breakage can be suppressed), and raw materials can be smoothly supplied to the second extruder. For this reason, the extrusion stability in the second extruder is improved, and the quality and shape of the pellet obtained from this extruder can be stabilized. In this manner, a series of extrusion steps using the first and second extruders and a subsequent EVOH molded article manufacturing step using pellets can be stabilized, and the quality of the molded article can be improved. According to the present invention using a plurality of extruders, for example, an EVOH containing no component B obtained from the first extruder and an EVOH resin composition containing the component B obtained from the second extruder are stable. Thus, EVOH molded articles of different brands can be efficiently produced using these. According to the present invention, loss at the time of brand switching can be avoided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. In one embodiment of the present invention, a part of EVOH (component A) having a water content of 5 to 40% by weight extruded from the first extruder is introduced into the second extruder together with the component B, and the second extruder is used. The mixture was melt-kneaded in the extruder and then discharged to obtain the remainder of EVOH obtained from the first extruder (without blending of component B) and the EVOH obtained from the second extruder (component B).
Is blended) with the EVOH resin composition. A plurality of extruders are prepared as a “second extruder”, and each extruder has a different component (components B1 and B).
, B3,...) May be introduced to produce more varieties. In this case, the EV obtained from the first extruder
All of the OH is distributed to the second extruder (s),
A plurality of brands of EVOH resin compositions containing different components B1, B2, B3,... May be obtained.

In another embodiment of the present invention, a component (component C) other than the components A and B is introduced into the first extruder. For example, EVOH (component A) and component C are melt-kneaded in a first extruder, extruded from the first extruder so that the water content becomes 5 to 40% by weight, and one of the extruded resin composition is extruded. Part was introduced into the second extruder together with the component B, melt-kneaded in the second extruder, and then discharged to obtain E (containing the component C) obtained from the first extruder.
The remainder of the VOH resin composition and the EVOH resin composition (containing component B and component C) obtained from the second extruder can be obtained. Heretofore, the introduction of multiple components in a single extruder has been considered exclusively. However, when trying to add various functions to a single extruder,
The screw diameter must be increased, and the ratio (L / D) of the screw length (L) to the screw diameter (D) must also be increased. On the other hand, in the above-mentioned method, since components are compounded using a plurality of extruders, it is not necessary to excessively increase the L / D, and it is possible to avoid an increase in production equipment costs,
The range of equipment selection can be expanded.

In the first extruder, the water content of the resin in the extruder may be adjusted by supplying water, removing water, or combining water supply and water removal. In this case, the water is preferably supplied and removed as a liquid. For example, moisture is also removed as water vapor from a vent provided for adjusting the pressure in the extruder, but in order to efficiently obtain a resin having a water content within a predetermined range, at least dehydration from the dewatering unit is performed. Is preferred. As described later, a cleaning liquid may be introduced into the first extruder. The components may be blended as an aqueous solution. When supplying these washing liquids and aqueous solutions to the extruder, in order to efficiently discharge water contained in each liquid, it is particularly desirable to dispose a liquid removing section. In supplying and / or removing water, the number and order of supply and removal are not limited.

As described above, components other than the components A and B (component C) are introduced into the first extruder as required. Component C is not particularly limited, but is preferably selected from highly versatile additives usually required for brands. Component C comprises a carboxylic acid,
At least one selected from a boron compound, a phosphoric acid compound, an alkali metal salt and an alkaline earth metal salt is preferred. Of course, various resins described below as representative examples of the component B may be used as the component C.

The component B to be introduced into the second extruder is also not particularly limited, and may be appropriately determined depending on whether or not the component C is added, and when it is added, according to its type. The above carboxylic acid and the like may be used as the component B.

Examples of the components B and C include various resins and plastic additives such as plasticizers, antioxidants, lubricants, ultraviolet absorbers, antistatic agents, flame retardants, and crystal nucleating agents. Among the plastic additives, an antioxidant is preferable. As the antioxidant, a hydrotalcite-based compound as an inorganic compound, hindered phenol, hindered amine, and a phosphorus-based antioxidant as organic compounds are preferable. Component B and component C do not need to be a single type, and a plurality of types of components may be introduced into each extruder.

An inorganic substance can also be used as the component B.
As inorganic substances, for example, glass fiber, glass flake,
Glass fillers such as glass beads; metal salts such as calcium carbonate, potassium titanate and barium sulfate; metal oxides such as alumina, titanium oxide, silicon dioxide, zinc oxide and zeolite; wollastonite; carbon fiber; And the like. An inorganic layered compound is a compound that has a structure in which atoms are strongly bonded by covalent bonds and the like to form a densely arranged sheet, and these sheets are stacked almost in parallel by van der Waals force, electrostatic force, etc. For example, talc, mica, kaolinite, montmorillonite, vermiculite and the like are applicable. The inorganic layered compound may be a natural product or a synthetic product. As the component B, an additive such as a carboxylic acid described later as a typical example of the component C may be used. Further, as a method of adding the above additives, a method of blending as a master batch previously blended with a resin composition other than the component A is also suitable.

As the component B, a resin is particularly preferable.
Above all, a resin compatible with EVOH, a resin having a functional group that reacts with EVOH, or a resin finely dispersed in EVOH is preferable.

Examples of the resin compatible with EVOH include 6
-Nylon, polyurethane, polyvinyl alcohol, ethylene-vinyl acetate copolymer and partially saponified products thereof,
Starch and the like. Further, EVOH having a different composition or molecular weight from EVOH of component A may be used as component B.

Examples of the resin having a functional group that reacts with EVOH include a polyolefin modified with a carboxylic acid derivative such as maleic anhydride, a molten mixture of an ionomer and a polyamide, and a boronic acid-modified resin.

Examples of the resin finely dispersed in EVOH include polymer fine particles having a core-shell structure.

Among these resins, the application of the present invention is particularly suitable for boronic acid-modified resins. This is because the viscosity of the resin composition is particularly important for the boronic acid-modified resin because the viscosity of the resin is increased by the reaction with the hydroxyl group of EVOH. Conventionally, as is generally practiced, in a method of melting and kneading dry resins, especially when a relatively large amount of a boronic acid-modified resin is blended with EVOH, thickening spots tend to occur, resulting in a strand. Inconveniences such as cuts and cut errors are likely to occur. EVO with water
When the H and the boronic acid-modified resin are melt-kneaded and the water content of the resin composition is adjusted, the above problem can be suppressed.

Here, the boronic acid-modified resin is at least one selected from a boronic acid group and a boron-containing group that can be converted to a boronic acid group in the presence of water (hereinafter simply referred to as “boron-containing group”). Refers to a resin having a functional group. That is, it is a resin in which at least one functional group selected from the group consisting of a boronic acid group and a boron-containing group is bonded to a main chain, a side chain, or a terminal by a boron-carbon bond.

The carbon in the boron-carbon bond is derived from a base polymer of the resin described later or from a boron compound reacted with the base polymer.
Preferred examples of the boron-carbon bond include boron and a main chain,
A bond to a terminal or side chain alkylene group is exemplified.

The boronic acid group is represented by the following formula (I).

[0024]

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The boron-containing group is not particularly limited as long as it can undergo hydrolysis in the presence of water to be converted into the boronic acid group represented by the above formula (I). Examples include a boronic ester group represented by the formula (II), a boronic anhydride group represented by the following general formula (III), and a boronic acid salt group represented by the following general formula (IV).

[0026]

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[0027]

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[0028]

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In the above formula, X and Y represent a hydrogen atom, an aliphatic hydrocarbon group (for example, a linear or branched alkyl or alkenyl group having 1 to 20 carbon atoms), and an alicyclic hydrocarbon group (for example, Represents a cycloalkyl group or a cycloalkenyl group) or an aromatic hydrocarbon group (for example, a phenyl group or a biphenyl group), and X and Y may be the same or different. In addition, X and Y may be bonded. However,
Except when X and Y are both hydrogen atoms (the same as in formula (I)). R ¹ , R ² and R ³ are the same as X and Y described above.
Represents a hydrogen atom, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group. Again, R ¹ , R ² , R ³
May be the same group or different. M represents an alkali metal. Note that the above X, Y, R ¹ , R ² ,
R ³ may contain other groups such as a carboxyl group and a halogen atom.

Specific examples of the boronic ester group represented by the general formula (II) include a boronic acid dimethyl ester group,
Boronic acid diethyl ester group, boronic acid dipropyl ester group, boronic acid diisopropyl ester group, boronic acid dibutyl ester group, boronic acid dihexyl ester group,
Boronic acid dicyclohexyl group, boronic acid ethylene glycol ester group, boronic acid propylene glycol ester group (boronic acid 1,2-propanediol ester group,
Boronic acid 1,3-propanediol ester group), boronic acid trimethylene glycol ester group, boronic acid neopentyl glycol ester group, boronic acid catechol ester group, boronic acid glycerin ester group, boronic acid trimethylolethane ester group and the like. Can be More specifically, the term "boron-containing group" refers to a resin in water or a liquid mixture of water and an organic solvent (toluene, xylene, acetone, or the like) for a reaction time of 10 minutes to 2 hours and a reaction temperature of 25 ° C to 150 ° C. When hydrolyzed under the condition of ° C.,
It means a group that can be converted into a boronic acid group.

The content of the functional group is not particularly limited,
0.0001 to 1 meq / g (milliequivalent / g) is preferable, and 0.001 to 0.1 meq / g is more preferable.

The monomers constituting the base polymer of the resin having at least one functional group selected from a boronic acid group and a boron-containing group include ethylene, propylene, 1-butene, isobutene, 3-methylpentene,
Olefin monomers represented by α-olefins such as -hexene and 1-octene; styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene,
-Methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene,
Styrenes such as-(phenylbutyl) styrene, 2,4,6-trimethylstyrene, monofluorostyrene, difluorostyrene, monochlorostyrene, dichlorostyrene, methoxystyrene, t-butoxystyrene;
-Vinyl group-containing aromatic compounds such as vinyl naphthalenes such as vinyl naphthalene and 2-vinyl naphthalene; vinyl aromatic compounds exemplified by vinylene group-containing aromatic compounds such as indene and acenaphthylene; butadiene, isoprene and 2,3-dimethyl Butadiene, pentadiene,
Examples thereof include conjugated diene compounds represented by hexadiene and the like.

The base polymer is used as a polymer composed of one, two or three or more of these monomers. Among these base polymers, in particular, ethylene polymers ｛ultra low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer Polymers, metal salts of ethylene-acrylic acid copolymers (Na, K, Zn-based ionomers), ethylene-propylene copolymer｝, and copolymers of a vinyl aromatic compound and a conjugated diene compound are preferred.

A typical method for producing a resin having at least one functional group selected from a boronic acid group and a boron-containing group will be described. The resin having this functional group is obtained by reacting a resin having a carbon-carbon double bond with a borane complex and a trialkyl borate under a nitrogen atmosphere to obtain a resin having a boronic acid dialkyl ester group. Alternatively, it can be obtained by reacting an alcohol. If a resin having a double bond at a terminal is used as a raw material in this production method, a resin having a boronic acid group or a boron-containing group at a terminal is obtained, and a resin having a double bond in a side chain or a main chain is used as a raw material. if,
A resin having a boronic acid group or a boron-containing group in the side chain is obtained.

As a typical method for producing a resin having a double bond as a raw material, 1) a method using a trace amount of a double bond existing at a terminal of an ordinary olefin polymer; 2) an ordinary olefin polymer. A process for obtaining an olefin polymer having a double bond at a terminal by thermal decomposition under oxygen-free conditions; 3) An olefin monomer and a diene monomer are obtained by copolymerization of an olefin monomer and a diene polymer. A process for obtaining a copolymer with the body;
4) a method of obtaining a copolymer of a vinyl aromatic compound and a conjugated diene-based monomer;

As for 1), a known method for producing an olefin polymer can be used. In particular, a method (for example, DE 4030399) using a metallocene polymerization catalyst as a polymerization catalyst without using hydrogen as a chain transfer agent is used. preferable. Regarding 2), a known method (for example, US28)
35659, 3087922), the olefin polymer is treated under an oxygen-free condition such as a nitrogen atmosphere or a vacuum condition.
It is obtained by pyrolysis at a temperature of 0 ° C to 500 ° C. Regarding 3), a method for producing an olefin-diene polymer using a known Ziegler catalyst (for example,
No. 44281, DE3021273) can be used.

By using the olefin polymer having a double bond obtained by the methods 1) and 2) as a raw material,
A polyolefin having at least one functional group selected from a boronic acid group and a boron-containing group bonded to the terminal is obtained. The olefin polymer having a double bond obtained by the method 3) and the copolymer comprising a vinyl aromatic compound and a conjugated diene compound obtained by the method 4) are used as raw materials to obtain the above functional group. Is bonded to the side chain.

As the borane complex, borane-tetrahydrofuran complex, borane-dimethylsulfide complex, borane-pyridine complex, borane-trimethylamine complex, borane-triethylamine complex and the like are preferable.
Triethylamine complexes and borane-trimethylamine complexes are more preferred. The amount of the borane complex charged is preferably 1/3 to 10 equivalents to the double bond of the base polymer. As the trialkyl borate, a lower alkyl borate such as trimethyl borate, triethyl borate, tripropyl borate and tributyl borate is preferable. The amount of the trialkyl borate charged is 1 to 10 with respect to the double bond of the olefin polymer.
0 equivalents are preferred. The solvent does not need to be used, but if used, hexane, heptane, octane,
Saturated hydrocarbon solvents such as decane, dodecane, cyclohexane, ethylcyclohexane and decalin are preferred.

The reaction to be introduced is performed at a reaction temperature of 25 ° C. to 300 ° C.
° C, preferably 100-250 ° C, reaction time 1 minute-10
Time, preferably 5 minutes to 5 hours. Conditions for reacting water or alcohols are usually
Using an organic solvent such as toluene, xylene, acetone or ethyl acetate as a reaction solvent, water or an alcohol such as methanol, ethanol or butanol; ethylene glycol, 1,2-propanediol, 1.3-propanediol or neopentyl glycol Glycerin, trimethylolethane, pentaerythritol, dipentaerythritol, etc., at 25 ° C. to 1
It is obtained by performing the reaction at a temperature of 50 ° C. for about 1 minute to 1 day.

Among these boronic acid-modified resins, EV
As the boronic acid-modified resin to be mixed with OH (component A), a resin having a polyolefin as a base polymer is preferable, and polyethylene is more preferably used as a base polymer. Further, in order to obtain good impact resistance while suppressing the occurrence of gels and bumps when blended with EVOH, a resin having at least one functional group selected from a boronic acid group and a boron-containing group at the terminal is required. It is preferable to use

Another preferred resin for component B is polyurethane. When polyurethane is blended by a conventional method, that is, a method of melt-kneading with EVOH in a dry state, spots of thickening occur in the extruder, causing problems such as broken strands and cut errors. For this reason, it has not been possible to melt-knead polyurethane in an extruder until now. However, when the water content is adjusted by melt-kneading EVOH and polyurethane in a water-containing state, the above-mentioned problem can be suppressed.

Further, in the case of a resin having a small difference between the thermal decomposition temperature and the melting point, such as polyvinyl alcohol, starch, and EVOH having a small ethylene content, the dried EVO
When melt-kneaded with H, polyvinyl alcohol and starch were thermally decomposed in an extruder, and foaming and coloring occurred, making it difficult to stably extrude. These resins are also suitable for component B because their melting points are lowered by the presence of moisture and can be melt-kneaded at a relatively low temperature.

Component B is not limited to these exemplified resins. For example, ethylene-vinyl acetate copolymers and ethylene-vinyl acetate copolymers which are incompatible with EVOH but can impart flexibility to EVOH by blending are used. Partially saponified polymer, polyethylene, amorphous nylon, 6
-12 nylon, styrene-butadiene block copolymer, styrene-isoprene block copolymer and the like can also be used.

Component B preferably has at least one of a melting point and a flow start temperature of 170 ° C. or less. This is because the resin becomes a molten state at the temperature in the extruder and exhibits good dispersibility in EVOH in a water-containing state. When the melting point and the flow start temperature exceed 170 ° C., an unmelted portion is generated in the extruder, a uniform dispersion state cannot be obtained, and a molding defect or an appearance defect may be induced.

Here, the flow start temperature is defined as a flow tester (constant load extrusion type capillary rheometer), which continuously measures the fluidity of the sample while raising the temperature as the test time elapses. This is the temperature when the fluid reaches the flow region through the rubber elastic region from the region.

The amount of Component B to be blended with respect to 100 parts by weight of EVOH is preferably 0.01 to 200 parts by weight. Component B
When is a resin, 1 to 200 parts by weight is suitable,
5-100 parts by weight are more preferred. If the amount of the resin is less than 1 part by weight, the effect of the resin compounding cannot be sufficiently exhibited in many cases. Specifically, in the case of a boronic acid-modified resin, flexibility is not sufficiently improved, and in the case of polyvinyl alcohol or starch, sufficient disintegration is often not obtained. On the other hand, when the compounding amount of the resin exceeds 200 parts by weight, the gas barrier property often becomes insufficient. Component B
Is an antioxidant, the preferred range of the amount is 0.0
1 to 5 parts by weight. When the amount is less than 0.01 part by weight, the antioxidant effect is hardly exhibited, and when the amount is more than 5 parts by weight, the antioxidant may bleed out from the molded product or the biting property to the extruder may be deteriorated. .

Hereinafter, the melting and kneading of EVOH in the extruder will be described more specifically with reference to FIGS. FIGS. 1 and 2 show a cylinder of a twin-screw extruder and a screw arranged inside the cylinder in order to facilitate description of an embodiment of the present invention.

The raw material supply section 1 of the first extruder shown in FIG.
Is heated, melted or semi-molten, and sent forward (to the right in the drawing) by the full flight screw 7a. EVOH is squeezed out of excess water in the liquid removing section 2 and mixed in the reverse flight screw section 8a. Further, the EVOH is sent to the full flight screw section 7b, and steam is released from the vent port 3 to further adjust the water content of the resin together with the pressure in the extruder.

Subsequently, the EVOH is sent to the reverse flight screw section 8b, and if necessary, the component C (for example, carboxylic acid, boron compound, phosphoric acid compound, alkali metal salt, And at least one selected from alkaline earth metal salts) in a molten state. Dewatered, but kneaded with additives E
VOH is still wet. Note that the temperature of the EVOH is controlled based on the temperature measured by the temperature sensor 5 disposed in the final full flight screw section 7c in the subsequent stage.

The water content of the EVOH resin composition extruded from the first extruder is controlled to 5 to 40% by weight. If the water content is too high, the resin and water contained in the resin are likely to undergo phase separation, and the strand immediately after discharge from the extruder is likely to foam. On the other hand, if the water content is too low, the viscosity of the resin increases, or it may cause thermal deterioration due to shear heat generation,
An excessive load is applied to the extruder, which may cause a failure. If the water content is not properly adjusted, when pellets are supplied to the second extruder, the pellets may be blocked by surface water. When the water content is within the above range, the extrusion stability in the second extruder is improved, and the quality and shape of pellets obtained from this extruder can be stabilized.

According to the embodiment, the water content can be adjusted by appropriately controlling the supply amount of water (including water contained in the washing liquid and the additives) to the extruder or the discharge amount of water from the extruder. Good.

The EVOH resin composition thus obtained is
It may be introduced into the second extruder as it is, or may be cut into pellets and then supplied to the second extruder. However, when a process of processing a part of the EVOH obtained from the first extruder into a molded product without passing through the second extruder is also used, a part of the pellet obtained by cutting is used. It is preferable to supply the mixture to the second extruder and pass the remainder to a drying step described later. In the illustrated form, from the raw material supply unit 11 of the second extruder shown in FIG. 2, together with at least a part of the EVOH resin composition (component A to which component C is added) discharged from the first extruder, Component B is introduced. Hereinafter, the EVOH resin composition is extruded from the second extruder sequentially through the full flight screw section 17a, the reverse flight screw section 18, and the full flight screw section 17b. Again, EVO
The temperature of the H resin composition may be controlled based on the temperature measured by the temperature sensor 15 arranged in the subsequent full flight screw portion 17b. The water content of the EVOH resin composition extruded from the second extruder is preferably 5 to 40% by weight immediately after extrusion for the same reason as described above.

The components A (component A optionally mixed with component C) and component B were introduced into the second extruder.
And component B may be dry-blended in advance and put into a hopper of an extruder, and component A and component B may be put into a hopper at the same time, and component A and component B are separately fed by two feeders. May be thrown. Among these, the method of feeding the component A and the component B respectively by two feeders is excellent in quantitative input and is excellent in reducing variation in quality. In addition, the shape of each component when put into the hopper is pellet, powder (including crumb shape)
The shape is not limited to a specific shape.

When a plurality of extruders are used as described above, the ratio (L / D) of the screw length (L) to the screw diameter (D) of each extruder can be reduced to a small range, for example, 20 to 5 mm.
It can be suppressed to about 0.

As the EVOH, one obtained by saponifying an ethylene-vinyl ester copolymer may be used. The ethylene content is usually preferably 3 to 70 mol%,
From the viewpoint of obtaining a molded product having excellent gas barrier properties and melt moldability, the ethylene content is preferably 10 to 60 mol%, more preferably 20 to 55 mol%, and particularly preferably 25 to 55 mol%. The saponification degree of the vinyl ester component in EVOH is usually preferably from 80 to 100 mol%, but from the viewpoint of obtaining a molded article having excellent gas barrier properties, it is preferably at least 95 mol%, particularly preferably at least 99 mol%.

On the other hand, E having an ethylene content of 3 to 20 mol%
VOH is suitably used as EVOH having water solubility. The aqueous solution containing EVOH has excellent barrier properties and coating film formability, and can be used as a coating material. EVOH having a saponification degree of 80 to 95 mol% is suitably used for improving the melt moldability. This EVOH may be used alone, or may be used as a blend with EVOH having a degree of saponification of more than 99 mol%.

EVOH having an ethylene content of 3 to 20 mol%
In any case of EVOH having a saponification degree of 80 to 95 mol%, it is difficult to precipitate as a pellet having a stable shape simply by extruding a methanol solution of EVOH into a coagulation bath in a strand shape. However, if the present invention is applied, pellets can be stably produced for the EVOH, and the resin blended in the EVOH can be made uniform.

If the ethylene content of EVOH is less than 3 mol%, melt moldability is poor, and water resistance, hot water resistance, and gas barrier properties under high humidity may decrease. on the other hand,
If it exceeds 70 mol%, the barrier properties and printability may be insufficient. On the other hand, if the saponification degree is less than 80 mol%, sufficient barrier properties, coloring resistance and moisture resistance cannot be obtained.

The water content of EVOH charged into the first extruder is preferably at least 0.5% by weight, more preferably at least 5% by weight, particularly preferably at least 7% by weight. This is because EVOH can be melted at a temperature lower than the melting point of EVOH in a dry state. Thus, thermal degradation of the EVOH in the extruder can be suppressed. On the other hand, the water content of EVOH charged into the extruder is 70%.
% By weight or less, more preferably 60% by weight or less, particularly preferably 50% by weight or less. If the water content exceeds 70% by weight, EVO
In the H resin composition, the resin and water contained in the resin are likely to undergo phase separation. When water causes phase separation, the resin surface becomes wet and friction increases, so that a bridge is easily generated in the hopper of the extruder, which may adversely affect the productivity of pellets.

The method for adjusting the water content of EVOH before it is charged into the first extruder is not particularly limited. In order to increase the water content, a method of spraying the resin with water, a method of immersing the resin in water, a method of bringing the resin into contact with water vapor, and the like may be employed. On the other hand, to lower the water content,
Various drying methods may be used. For example, a method of drying using a fluidized hot air dryer or a stationary hot air dryer may be used. However, it is preferable to use a fluidized hot air dryer from the viewpoint of reducing drying spots. In order to suppress thermal deterioration, the drying temperature is preferably 120 ° C. or lower.

The EVOH is preferably a pellet obtained by cutting a strand precipitated in a coagulation bath, but the shape of the EVOH is not particularly limited as described above.
A crumb-like precipitate obtained by solidifying the paste in an irregular shape may be used. The EVOH paste may be directly charged into the extruder.

The saponification catalyst residue can be removed from EVOH by washing in the extruder. Specifically, the cleaning liquid is injected from at least one location of the extruder,
Clean the EVOH and remove at least one downstream of the injection section.
The cleaning liquid may be discharged from the location. Conventionally, the resin pellets are put in a washing vessel in a solid state and brought into contact with a washing solution, thereby extracting saponification catalyst residues by relying on diffusion from inside the pellets. However, when washing is performed simultaneously in the extruder, washing can be performed efficiently and in a space-saving manner.

The residue of the saponification catalyst contained in the EVOH supplied to the extruder is typically an alkali metal ion. When the content of the alkali metal ion is in the range of 0.1 to 5% by weight in terms of metal, a great effect can be obtained by applying the above-described cleaning method in the extruder. When the content is less than 0.1% by weight, there is not much difference from the case where the conventional cleaning method is applied. Conversely, when the content exceeds 5% by weight,
Even if the present invention is applied, an extruder having a large screw length (L) / screw diameter (D) is required to perform sufficient washing, which may cause an increase in cost. The content is preferably 0.2% by weight or more, particularly 0.5% by weight or more, and more preferably 4% by weight or less, particularly 3% by weight or less.

The alkali metal ion contained in the EVOH after washing is preferably 0.05% by weight or less, more preferably 0.04% by weight or less, particularly preferably 0.03% by weight or less in terms of metal. If the alkali ion metal ion remains in excess of 0.05% by weight, the thermal stability of EVOH may decrease.

The washing solution used in this case is not particularly limited as long as it can remove the saponification catalyst residue. For example, water can be used, but an aqueous solution of an acid having a pKa of 3.5 or more at 25 ° C. Is preferred. When an aqueous solution of an acid having a pKa of less than 3.5 is used, the EVOH may not have sufficient coloring resistance and interlayer adhesion in some cases. pKa
As the acid having a value of 3.5 or more, a carboxylic acid, particularly acetic acid or propionic acid, is suitable. The carboxylic acid concentration in the carboxylic acid aqueous solution is preferably from 0.01 to 10 g / L, particularly preferably from 0.1 to 2 g / L. Further, the injection amount of the cleaning liquid is preferably about 0.1 to 100 liters per 1 kg of EVOH.

The method of injecting the cleaning liquid is not particularly limited as long as it can be injected into the extruder. For example, the cleaning liquid may be injected by using a plunger pump or the like. The method for discharging the cleaning liquid is not particularly limited as long as the liquid can be discharged from the extruder on the downstream side of the injection section. For example, a dehydration slit or a dehydration hole may be used. In this way, the water content of the resin is adjusted together with the discharge of the cleaning liquid. Note that a plurality of injection sections and a plurality of liquid removal sections may be arranged.

With a dehydrating slit or a dehydrating hole, any liquid or gas can be discharged, and water can be efficiently removed from a resin having a high moisture content. In this case, a dehydration slit or a dehydration hole may be used. In contrast, vent ports (vacuum vents for removing water vapor under reduced pressure and open vents for removing water vapor under normal pressure) can generally only discharge water vapor.
It is also necessary to consider the possibility that the resin adhering to the vent port deteriorates and enters the extruder. In addition, since the molten resin may protrude from the dewatering holes, the dewatering slit is more preferable from such a viewpoint. Examples of the dewatering slit include a wedge wire type dewatering slit and a screen mesh type dewatering slit.

The dehydrating means exemplified above may be used alone, but a plurality of the same type may be used, or different types may be used in combination. For example, water may be removed from a resin having a high moisture content using a dewatering slit, and steam may be further removed from a vent port on the downstream side.

Next, additives selected from carboxylic acids, boron compounds, phosphoric acid compounds, alkali metal salts and alkaline earth metal salts will be described. Of course, these additives may be added alone, but it is preferable to improve various performances of EVOH by adding a plurality of types selected according to the embodiment.

Addition of a carboxylic acid to EVOH can improve thermal stability. Examples of the carboxylic acid include oxalic acid, succinic acid, benzoic acid, citric acid, acetic acid, propionic acid, and lactic acid, but acetic acid, propionic acid, or lactic acid is preferable in consideration of cost and the like.

The content of carboxylic acid is determined by drying EVOH
In a resin composition pellet, 10 to 5000 ppm is preferable. If the content of the carboxylic acid is less than 10 ppm, the coloring resistance at the time of melt molding may not be sufficiently obtained, and if it exceeds 5000 ppm, the interlayer adhesion may be insufficient. The lower limit of the carboxylic acid content is preferably at least 30 ppm, more preferably at least 50 ppm. On the other hand, the upper limit of the carboxylic acid content is preferably 1
000 ppm or less, more preferably 500 ppm
It is as follows.

When a phosphoric acid compound is added to EVOH, the thermal stability can be improved. The content of the phosphate compound in the dried EVOH resin composition pellets is 1 to 10 in terms of phosphate group.
00 ppm is preferred. By adding the phosphoric acid compound in an appropriate range, it becomes possible to suppress the coloring of the molded article and the generation of gels and bumps. The above-mentioned improvement effect by the addition of the phosphoric acid compound is particularly remarkable at the time of long run molding using the EVOH resin composition pellets and at the time of collecting the molded product. Examples of the phosphoric acid compound include, but are not limited to, various acids such as phosphoric acid and phosphorous acid and salts thereof. The phosphate may be a first phosphate, a second phosphate, a third phosphate.
The phosphate may be contained in any form, and the cation species is not particularly limited, but is preferably an alkali metal salt or an alkaline earth metal salt. Among them, phosphoric acid 2
Sodium hydrogen phosphate, potassium dihydrogen phosphate, hydrogen phosphate 2
It is preferable to add a phosphate compound as sodium and dipotassium hydrogen phosphate.

The content of the phosphoric acid compound in the dried EVOH resin composition pellets was 10 p
pm or more, especially 30 ppm or more, more preferably 500 ppm or less, especially 300 ppm or less. When the phosphoric acid compound is contained in such a range, it is possible to obtain pellets with less coloring and less gelation. If the content of the phosphoric acid compound is less than 1 ppm, the effect of suppressing coloring during melt molding may not be sufficiently obtained. In particular, when the heat history is repeated, the tendency becomes remarkable, so that the molded product obtained by molding the pellet may have poor recoverability. On the other hand, when the content of the phosphoric acid compound exceeds 1000 ppm, gels and bumps of the molded article are easily generated.

When a boron compound is added to EVOH,
The thermal stability and mechanical properties of VOH can be improved. This is considered to be because a chelate compound is generated between the EVOH and the boron compound. Boron compounds include, but are not limited to, boric acids, borate esters, borates, borohydrides, and the like. Examples of the boric acids include orthoboric acid, metaboric acid, tetraboric acid, and the like.Examples of borate esters include triethyl borate, trimethyl borate, and the like.As the borate, alkali metal salts of the above various boric acids. , Alkaline earth metal salts, borax and the like. Among these compounds, orthoboric acid (hereinafter, simply referred to as "boric acid") is preferable.

The content of the boron compound in the dried EVOH resin composition pellets is 10 to 2000 pp in terms of boron.
m, more preferably 50 to 1000 ppm. 10pp
If it is less than 2,000 m, the effect of improving the thermal stability by adding a boron compound may not be sufficiently obtained.
If it exceeds pm, gelation is likely to occur and moldability may be poor.

When an alkali metal salt is added to EVOH,
The interlayer adhesion and compatibility can be effectively improved. Dried EVO
The content of the alkali metal salt in the H resin composition pellets,
5 to 5000 ppm in terms of alkali metal element, and 2
0 to 1000 ppm, especially 30 to 750 ppm is preferred. Examples of the alkali metal include lithium, sodium, and potassium, and examples of the alkali metal salt include an aliphatic carboxylate, an aromatic carboxylate, a phosphate, and a metal complex. Examples thereof include sodium acetate, potassium acetate, sodium propionate, potassium propionate, sodium phosphate, lithium phosphate, sodium stearate, potassium stearate, and sodium salt of ethylenediaminetetraacetic acid. Among them, sodium acetate, potassium acetate, sodium propionate, potassium propionate, and sodium phosphate are preferred.

When the alkaline earth metal salt is added to EVOH, the effect of improving the color resistance is slightly reduced, but the amount of the thermally deteriorated resin adhered to the die of the molding machine during the melt molding of the pellets is reduced. Becomes possible. Examples of the alkaline earth metal salt include, but are not particularly limited to, magnesium salt, calcium salt, barium salt, beryllium salt, and the like, and magnesium salt and calcium salt are preferable. The anionic species of the alkaline earth metal salt is not particularly limited, but is preferably an acetate anion, a propionate anion, or a phosphate anion.

The content of the alkaline earth metal salt in the dried EVOH resin composition pellets is 10 to 100 in terms of the same metal.
0 ppm, more preferably 20-500 ppm, is preferred. When the content of the alkaline earth metal is less than 10 ppm, the effect of improving long-run properties may be insufficient,
If it exceeds 0 ppm, coloring at the time of resin melting may not be sufficiently suppressed.

When the above additives such as carboxylic acid are blended in the extruder, these additives can be uniformly kneaded. In this way, the extrusion torque and the torque fluctuation of the extruder during melt molding are small, so that the extrusion stability,
It is possible to obtain EVOH resin composition pellets which are excellent in coloring resistance and long run property, and have little gel / bubble generation and a small amount of die attached. Further, the above additive is EVOH
Is supplied to a position that is wet and in a molten state,
The above effects can be sufficiently obtained. Further, when the additives are supplied to the kneading section of the extruder, the additives are more easily compounded.

The method of adding the above additives such as carboxylic acid is not particularly limited. Examples thereof include a method of adding it as a dry powder in an extruder, a method of adding it as a paste impregnated with a solvent, a method of adding it in a state of being suspended in a liquid, and a method of dissolving it in a solvent and adding it as a solution. From the viewpoint of controlling the amount of addition and uniformly dispersing the additive in EVOH, a method of adding the additive as a solution in which the additive is dissolved in a solvent is particularly preferable. In this case, the solvent is not particularly limited, but water (aqueous solution) is preferable in consideration of the solubility of the additive, the merit in cost, the ease of handling, the safety of the working environment, and the like. The additives may be added from one place of the extruder, but may be added from two or more places. The method for injecting the solution is not particularly limited as in the case of the cleaning solution.

When the above-mentioned additives such as carboxylic acid are added as a solution to EVOH, the lower limit of the amount of the solution to be added is 1 part by weight or more, and further 3 parts by weight, based on 100 parts by weight of the dry weight of EVOH. Parts or more, particularly preferably 5 parts by weight or more. The upper limit of the amount of the solution added is 50 parts by weight or less, and more preferably 30 parts by weight or less based on 100 parts by weight of the dry weight of EVOH.
It is preferably at most 20 parts by weight, especially at most 20 parts by weight. When the addition amount of the solution is less than 1 part by weight, generally, the concentration of the solution becomes so high that the effect of improving the dispersibility of the additive may not be sufficiently obtained. On the other hand, when the addition amount of the solution is larger than 50 parts by weight, it may be difficult to control the water content of the EVOH, and the resin and the water contained in the resin are easily separated in the extruder.

Conventionally, a processing method of immersing EVOH in a processing solution has been known, but in such a method, EVOH is used.
It was difficult to obtain good quality products for crumb-like precipitates of OH and the like. However, when compounded in an extruder, it is possible to uniformly add an additive such as a carboxylic acid to EVOH in such a form, and it is possible to obtain EVOH resin composition pellets of stable quality.

[0083] The resin temperature in the first and second extruders is preferably 70 to 170 ° C. 7 resin temperature
If the temperature is lower than 0 ° C., the EVOH may not completely melt. Further, when various additives are blended with EVOH in a molten state, the effect of improving dispersibility becomes higher. The resin temperature is
80 ° C. or higher, particularly 90 ° C. or higher, is preferable. On the other hand, if the resin temperature exceeds 170 ° C., the EVOH is susceptible to thermal degradation. From this viewpoint, the resin temperature is preferably 150 ° C. or lower, more preferably 130 ° C. or lower. The method for adjusting the resin temperature is not particularly limited, but a method for appropriately setting the temperature of the cylinder in the extruder is preferable. In particular, when a resin is blended as the component B in the second extruder, it is important to keep the resin temperature in the extruder within the above range.

Incidentally, the resin temperature may be determined by applying the temperature measured by a temperature sensor installed in the extruder cylinder. The temperature sensor is suitably installed near the extruder tip discharge port.

The method of pelletizing the EVOH resin composition discharged from the extruder is not particularly limited, but the resin composition may be extruded from a die in a strand shape into a coagulation bath and cut into an appropriate length. In order to facilitate the handling of the pellet, the diameter of the die is 2 to 5 mmφ (φ is the diameter.
The same applies below), and the strand may be cut to a length of about 1 to 5 mm.

The pellets obtained from the second extruder (and, if necessary, the rest of the pellets obtained from the first extruder but not charged into the second extruder) are usually
It is subjected to a drying step. The moisture content of the dried EVOH resin composition pellets is preferably 1% by weight or less, more preferably 0.5% by weight. The drying method is not particularly limited,
A stationary drying method, a fluidized drying method, or the like is preferable, and a multi-stage drying process in which several drying methods are combined may be applied. Among them, a method of first drying by a fluidized drying method and subsequently drying by a static drying method is preferable.

When the EVOH resin composition pellets are simply immersed in a treatment solution for treatment, the water content of the EVOH after treatment becomes
Usually, it reaches about 40 to 70% by weight. However, as in the present invention, when EVOH is melted by an extruder and a necessary treating agent is added in the extruder, the water content of the EVOH resin composition immediately after the extruder is discharged can be easily adjusted.
The water content in the EVOH resin composition is preferably 5 to 5.
40% by weight. By using such pellets having a small water content, energy consumption in the drying step can be reduced.

Pellets having a water content exceeding 40% by weight are:
When the drying temperature is set to 100 ° C. or higher, fusion between the pellets may occur. Also in this respect, the compounding of the additives in the extruder is advantageous.

It is also possible to blend the EVOH resin composition pellets obtained by the above method with EVOH having different degrees of polymerization, ethylene content and saponification degree and melt-mold. In addition, other various plasticizers, stabilizers, surfactants, coloring agents, ultraviolet absorbers, antistatic agents, desiccants, crosslinking agents, metal salts, fillers, reinforcing agents for various fibers, etc. are added to the pellets in appropriate amounts. It is also possible to add.

It is also possible to add an appropriate amount of a thermoplastic resin other than EVOH as long as the object of the present invention is not impaired. As the thermoplastic resin, various polyolefins (polyethylene, polypropylene, poly 1-butene, poly 4-methyl-1-pentene, ethylene-propylene copolymer,
A copolymer of ethylene and an α-olefin having 4 or more carbon atoms, a copolymer of a polyolefin and maleic anhydride, an ethylene-vinyl ester copolymer, an ethylene-acrylate ester copolymer, or an unsaturated carboxylic acid A modified polyolefin graft-modified with an acid or a derivative thereof), various nylons (nylon-6, nylon-
6,6, nylon-6 / 6,6 copolymer), polyvinyl chloride, polyvinylidene chloride, polyester, polystyrene, polyacrylonitrile, polyurethane, polyacetal, and modified polyvinyl alcohol resin.

The obtained EVOH resin composition pellets
It is formed into various molded products such as films, sheets, containers, pipes, and fibers by melt molding. These compacts are
It may be pulverized and formed again for the purpose of reuse. It is also possible to uniaxially or biaxially stretch films, sheets, fibers and the like. Extrusion molding, inflation extrusion, blow molding, melt spinning, injection molding and the like can be applied as the melt molding method. The melting temperature may be appropriately selected depending on the melting point of the copolymer and the like, but is preferably about 150 to 270 ° C.

The EVOH resin composition pellets may be formed into a film, a sheet, or the like, and put to practical use as a multilayer structure with other layers. The multilayer structure is not particularly limited. When the EVOH resin composition is represented by E, the adhesive resin is represented by Ad, and the thermoplastic resin is represented by T, E / Ad / T,
T / Ad / E / Ad / T and the like. Each layer may be a single layer or a multilayer.

The multilayer structure may be formed into various shapes as it is, but may be subjected to a stretching treatment to improve physical properties. When stretch processing is performed, breakage, pinhole,
A stretched film, a stretched sheet, or the like in which stretching unevenness, delamination, and the like do not occur can be obtained. Stretching may be either uniaxial stretching or biaxial stretching, and in general, the higher the draw ratio, the better the physical properties. As a stretching method, besides a roll stretching method, a tenter stretching method, a tubular stretching method, a stretch blow method, and the like, a deep drawing method, a vacuum forming method, or the like having a high stretching ratio may be employed. In the case of biaxial stretching, any of a simultaneous biaxial stretching method and a sequential biaxial stretching method may be applied. The stretching temperature is, for example, 80 to
The temperature is 170 ° C, preferably 100 to 160 ° C.

After completion of the stretching, heat setting is preferably performed.
The heat setting may be performed by a conventional method. For example, the heat setting may be performed while keeping the stretched film under tension.
0 to 170 ° C, preferably 2 to 60 at 100 to 160 ° C
What is necessary is just to process for about 0 second. The obtained stretched film is
If necessary, a cooling process, a printing process, a dry laminating process, a solution or melt coating process, a bag making process, a box process, a tube process, a split process, and the like may be performed.

[0095]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In addition, all the water used ion-exchange water. The evaluation method of each characteristic is as follows.

(1) Measurement of water content 20 g of water-containing EVOH as a sample was placed in a well-dried weighing bottle, dried with a hot air drier at 120 ° C. for 24 hours, and the following equation was obtained from the change in weight of EVOH before and after drying. Was used to determine the water content of EVOH.

Water content (% by weight) = {(weight before drying−weight after drying) / weight before drying} × 100

(2) Quantification of added trace components Quantification was performed according to the following method. In the following, the term "dry chips" refers to an EV to which at least one selected from a carboxylic acid, a boron compound, a phosphoric acid compound, an alkali metal salt and an alkaline earth metal salt is added in an extruder.
It is obtained by drying the OH resin composition pellets at 100 ° C. for 15 hours using a fluidized hot air drier and subsequently drying at 100 ° C. for 15 hours using a stationary hot air drier.

(2-a) Determination of acetic acid content 20 g of a dry chip as a sample was put into 100 ml of water.
Heat extraction was performed at 95 ° C for 6 hours. The extract was subjected to neutralization titration with 1 / 50N NaOH using phenolphthalein as an indicator to determine the acetic acid content.

(2-b) Quantification of Na, K, and Mg Ions 10 g of a dry chip as a sample was put into 50 ml of a 0.01 N hydrochloric acid aqueous solution, and stirred at 95 ° C. for 6 hours. The aqueous solution after stirring was quantitatively analyzed using ion chromatography, and the amounts of Na, K, and Mg ions were quantified. The column is
"ICS-C25" manufactured by Yokogawa Electric Corporation was used, and the eluent was an aqueous solution containing 5.0 mM tartaric acid and 1.0 mM 2,6-pyridinedicarboxylic acid. In the determination, a calibration curve prepared with an aqueous solution of sodium chloride, an aqueous solution of potassium chloride, and an aqueous solution of magnesium chloride was used. From the amounts of Na, K, and Mg ions thus obtained,
The amounts of the alkali metal salt and alkaline earth metal salt in the dried chips were obtained in terms of metal.

(2-c) Determination of Boron Compound An aqueous solution of Na ₂ CO ₃ was added to a dry chip to be used as a sample, and ashed at 600 ° C. in a platinum crucible. Hydrochloric acid was added to the obtained sample to dissolve it, and the content of the boron compound was quantified in terms of boron by ICP emission spectroscopy.

(2-d) Determination of Phosphate Ion 10 g of a dry chip to be used as a sample was put into 50 ml of a 0.01 N hydrochloric acid aqueous solution and stirred at 95 ° C. for 6 hours. The aqueous solution after stirring was quantitatively analyzed using ion chromatography to determine the amount of phosphate ions. The column used was “ICS-A23” manufactured by Yokogawa Electric Corporation, and the eluent was 2.5
An aqueous solution containing mM sodium carbonate and 1.0 mM sodium bicarbonate was used. In the determination, a calibration curve prepared with a phosphoric acid aqueous solution was used. From the amount of the phosphate ions thus obtained, the content of the phosphate compound was obtained in terms of phosphate groups.

(3) Method of Measuring Flow Start Temperature Using a flow tester (constant load extrusion type capillary rheometer), the fluidity of the sample was continuously measured while increasing the temperature with the passage of the test time, and the following method was used. The flow start temperature was determined using the attached analysis software.

Apparatus: Shimadzu flow tester CFT-500
D / 100D (manufactured by Shimadzu Corporation) Model: Constant load extrusion method Test method: Heating method Initial temperature: 100 ° C Heating rate: 5 ° C / min Die: 1 mmφ × 10 mm Measurement load: 100 kg Measurement position: 0 to 15 mm Analysis software : CFT-500D type / 100D personal computer software Operation: Take 2 g of sample and put into cylinder.
After charging the sample, preheat it for 6 minutes and start measurement. 3 ℃
The stroke (piston position) is measured every time, and a temperature-piston extrusion stroke curve is created. Flow start temperature calculation method (1/2 method): In the temperature-piston extrusion stroke curve (flow curve), 1/2 of the difference between the outflow end point (Smax) and the lowest point (Smin) is obtained, and (X = (Smax) −Smin) / 2), X and Smi
The temperature at which n was added was defined as the flow start temperature. The melting point is
It was measured according to JIS K7122.

(4) Melt Index (MI) Measured under the conditions of a temperature of 190 ° C. and a load of 2160 g using a melt indexer according to ASTM-D1238.

Example 1 An ethylene content of 44 mol%
EVOH pellets having a saponification degree of 99.5 mol%, a melt index of 5 g / 10 min when dried, and a water content of 50 wt% are charged from the raw material supply section 1 of the first extruder having a structure similar to that shown in FIG. Then, excess water is derived from the liquid removing part (liquid removing slit) 2 and excess water vapor is derived from the vent port 3, respectively.
An aqueous solution consisting of acetic acid / potassium dihydrogen phosphate / sodium acetate / magnesium acetate was added from the trace component addition section 4.

The amount of EVOH pellets charged per unit time was 10 kg / hour (including the weight of water contained), and the amount of the aqueous solution added from the trace component addition section was 0.25 L / hour. At this time, the composition of the aqueous solution was acetic acid 5 g / L, potassium dihydrogen phosphate 2.8 g / L, and sodium acetate 9.
It was 2 g / L and magnesium acetate 6 g / L.

The specifications of the first extruder are shown below (the configuration is the same as in FIG. 1). Type Twin screw extruder L / D 30 Caliber 30mmφ Screw Co-rotation perfect meshing type Rotational speed 300rpm Motor capacity DC22KW Heater 9-segment type Number of die holes 5 holes (3mmφ) Resin temperature in extruder 130 ° C Take-off speed 5m / min

The strand discharged from the die of the first extruder is used as a fan cutter (“FC-1” manufactured by Hoshi Plastics Co., Ltd.).
08S-1 ") to give EVOH pellets. The water content of the pellets was 20% by weight.

Polyurethane (Kuraray “Kuramilon (registered trademark) U1780”) was prepared as Component B together with the EVOH pellets (Component A). These components A and B were fed from the raw material supply section 8 of the second extruder having the same structure as shown in FIG. The input amount of pellets per unit time was 6.25 kg / hour (including the weight of water contained), and the input amount of polyurethane per unit time was 2 kg / hour.

The specifications of the second extruder are shown below (the configuration is the same as in FIG. 1). Type Twin screw extruder L / D 30 Caliber 30mmφ Screw Full co-rotating in the same direction Rotation speed 300rpm Motor capacity DC22KW Heater 9-segment type Number of die holes 5 holes (3mmφ) Resin temperature in extruder 140 ° C Take-off speed 5m / min

The water content of the strand discharged from the die was measured and found to be 15% by weight. After cooling the strand obtained from the discharge port in a water bath, an EVOH resin composition pellet was obtained using a fan cutter in the same manner as described above. At this time, the stability of the strand was evaluated. As a result, there was no occurrence of strand breakage or the like, which was favorable.

[0113] The obtained pellets were subjected to 1
After drying at 00 ° C. for 25 hours and subsequently using a stationary dryer at 100 ° C. for 15 hours, the water content was 0.1% by weight. The content of acetic acid in the EVOH resin composition pellets after drying is 200 ppm, the content of phosphoric acid compound is 60 ppm in terms of phosphate, the content of alkali metal salt is 20 ppm in terms of potassium, and 80 pp in terms of sodium.
m, and the content of the alkaline earth metal salt was 30 ppm in terms of magnesium. In addition, as a result of observing the shape of the resin composition pellet, no cut mistake or the like was found, and the shape was good. The above results are collectively shown in Tables 1 to 4.

Example 2 An EVOH resin composition pellet was obtained in the same manner as in Example 1 except that EVOH was used as the component B.
The EVOH used as the component B used was "EXEVAL (registered trademark) RS4105" manufactured by Kuraray Co., Ltd. (ethylene content: 9 mol%, saponification degree: 98 mol%), and water content: 5% by weight. As in Example 1, the stability of the strand was good, and the shape of the obtained pellet was also good. Details such as extrusion conditions, processing solution composition, and pellet analysis results,
The results are shown in Tables 1 to 4.

Example 3 An EVOH resin composition pellet was obtained in the same manner as in Example 1 except that EVOH was used as the component B.
EVOH used as the component B has an ethylene content of 52 mol%,
Degree of saponification: 95 mol%, melt index: 6 g / 10
And a water content of 0.3% by weight. As in Example 1, both the stability of the strand and the shape of the pellet were good. Tables 1 to 4 show details such as the extrusion conditions, the composition of the processing solution, and the analysis results of the pellets.

Example 4 An EVOH resin composition pellet was obtained in the same manner as in Example 1 except that EVOH was used as the component B.
EVOH used as the component B is "EVAL (registered trademark) F101" manufactured by Kuraray Co., Ltd. (ethylene content: 32 mol%)
100 parts by weight and “Irganox (registered trademark) 10” manufactured by Ciba Specialty Chemicals as an antioxidant.
98 ", 1 part by weight, and an EVOH composition having a water content of 0.1%.
3% by weight was used. As in Example 1, both the stability of the strand and the shape of the pellet were good. Tables 1 to 4 show details such as the extrusion conditions, the composition of the processing solution, and the analysis results of the pellets.

Example 5 Low density polyethylene (LDP)
Using E) as the component B, an EVOH resin composition pellet was obtained in the same manner as in Example 1. Low density polyethylene is manufactured by Nippon Polychem Co., Ltd. “Novatech (registered trademark) LJ900”.
N "was used. As in Example 1, both the stability of the strand and the shape of the pellet were good. Details of extrusion conditions, treatment liquid composition, and results of pellet analysis are shown in Tables 1 to 4.
Shown in

Examples 6 to 8 EVOH resin composition pellets were obtained in the same manner as in Example 1 except that the boronic acid group-containing thermoplastic resin was used as the component B.

A method for producing a boronic acid group-containing thermoplastic resin will be described below. First, very low density polyethylene (VLDP)
E, Sumitomo Chemical "Excellen (registered trademark) EUL43"
0 ") was replaced with 13 L of nitrogen at 1 L / min.
It was fed at a rate of kg / h to a twin screw extruder. Next, a liquid mixture of borane-triethylamine complex and 1,3-butanediol borate (borane-triethylamine complex (TEAB) / 1,3-butanediol borate (BBD) = 29/71 from the liquid feeder 1; Weight ratio)
From the liquid feeder 2 at a rate of 0.6 kg / hr.
3-butanediol is fed at a rate of 0.5 kg / h,
Kneaded continuously. During kneading, vent 1 and vent 2
The pressure was adjusted such that the gauge indicated about 20 mmHg. As a result, ultra-low density polyethylene (BR-VLDPE) containing 1,3-butanediol boronic acid ester group was obtained at a rate of 13 kg / hour from the discharge port.

This BR-VLDPE had a functional group content of 47 μm.
mol / g, double bond amount 0 μmol / g and melt index (MI) 4 g / 10 min (190 ° C., 21
60 g).

The structure of the twin screw extruder used for the reaction,
The operating conditions are as follows. Coaxial twin screw extruder TEM-35B (manufactured by Toshiba Machine) Screw diameter: 37 mmφ L / D: 52 (15 blocks) Liquid feeder: C3 (liquid feeder 1), C11 (liquid feeder 2) Vent position: C6, C14 Screw Configuration: Use seal ring between C5-C6, between C10-C11 and C12 Temperature setting: C1 Water cooling C2-C3 200 ℃ C4-C15 250 ℃ Die 250 ℃ Screw rotation speed: 400rpm

Also when BR-VLDPE was used, the stability of the strand and the shape of the obtained pellet were good. Tables 1 to 4 show details such as the extrusion conditions, the composition of the processing solution, and the analysis results of the pellets.

Comparative Example 1 A 45% by weight methanol solution of an ethylene-vinyl acetate copolymer having an ethylene content of 44 mol% was charged into a saponification reactor, and a sodium hydroxide / methanol solution (80 g / L) was added to the copolymer. Was added so as to be 0.4 equivalent to the vinyl acetate component, and methanol was added to adjust the copolymer concentration to 20% by weight.
The temperature was raised to 60 ° C., and the reaction was carried out for about 4 hours while blowing nitrogen gas into the reactor. After 4 hours, the reaction was terminated by neutralization with acetic acid to obtain a methanol solution of EVOH having an ethylene content of 44 mol% and a saponification degree of 99.5 mol%.

The EVOH solution was extruded from a metal plate having a circular opening into water to precipitate a strand, and cut to obtain a pellet having a diameter of about 3 mm and a length of about 5 mm. The operation of removing the obtained pellet by a centrifugal separator, adding a large amount of water, and removing the liquid was repeated.

3.5 kg of the EVOH pellets (water content 55% by weight) thus obtained were mixed with an acetic acid concentration of 0.4 g / L.
Potassium dihydrogen phosphate concentration 0.1 g / L, sodium acetate concentration 0.4 g / L, magnesium acetate concentration 0.3 g / L
The resultant was immersed in 6 L of an aqueous solution at room temperature for 6 hours. After immersion,
The solution was drained to obtain EVOH pellets having a water content of 55% by weight.
Further, the pellets were put into a fluidized drier and dried at 80 ° C. for 15 hours and subsequently at 100 ° C. for 24 hours using a stationary drier to obtain EVOH pellets having a water content of 0.1% by weight. The obtained EVOH pellets are acetic acid 300 pp
m, the phosphate compound was 100 ppm in terms of phosphate group, the alkali metal salt was 40 ppm in terms of potassium, 130 ppm in terms of sodium, and the alkaline earth metal was 50 ppm in terms of magnesium. Melt index is 5g /
10 minutes.

The EVOH pellets were used in Example 1 at a rate of 10 kg / hour (including the weight of the contained water) from the raw material supply section of an extruder (second extruder) having a structure similar to that shown in FIG. The obtained polyurethane was charged at a rate of 4 kg / hour.
The water content of the strand discharged from the die is 0.1% by weight
Met. After cooling the strand obtained from the discharge port of the extruder in a water tank, an EVOH resin composition pellet was obtained using a fan cutter in the same manner as in Example 1. But,
The stability of the strand was low, and the strand was frequently broken, so that a stable sample could not be collected. In the shape of the obtained pellet, cut errors were inconspicuous and poor.

The obtained resin composition pellets were dried at 100 ° C. for 25 hours using a fluidized drier and subsequently at 100 ° C. for 15 hours using a stationary drier. The moisture content of the dried resin composition pellets was 0.1% by weight. Tables 1 to 4 show details such as the extrusion conditions, the composition of the processing solution, and the analysis results of the pellets.

Comparative Example 2 The thermoplastic resin having a boronic acid group used in Example 6 was used as the component B, and pellets of an EVOH resin composition were obtained in the same manner as in Comparative Example 1. Strand breakage occurred frequently, and stable sampling was not possible. In the shape of the obtained pellet, cut errors were inconspicuous and poor. Tables 1 to 4 show details such as the extrusion conditions, the composition of the processing solution, and the analysis results of the pellets.

Comparative Example 3 A 45% by weight methanol solution of an ethylene-vinyl acetate copolymer having an ethylene content of 44 mol% was charged into a saponification reactor, and a sodium hydroxide / methanol solution (80 g / L) was added to the copolymer. Was added so as to be 0.4 equivalent to the vinyl acetate component, and methanol was added to adjust the copolymer concentration to 20% by weight.
The temperature was raised to 60 ° C., and the reaction was carried out for about 4 hours while blowing nitrogen gas into the reactor. After 4 hours, the reaction was terminated by neutralization with acetic acid to obtain a methanol solution of EVOH having an ethylene content of 44 mol% and a saponification degree of 99.5 mol%.

The EVOH solution was extruded from a metal plate having a circular opening into water to precipitate strands, and cut to obtain pellets having a diameter of about 3 mm and a length of about 5 mm. The operation of removing the obtained pellet by a centrifugal separator, adding a large amount of water, and removing the liquid was repeated.

3.5 kg of the EVOH pellets (water content: 55% by weight) thus obtained were mixed with an acetic acid concentration of 0.4 g / L.
Potassium dihydrogen phosphate concentration 0.1 g / L, sodium acetate concentration 0.4 g / L, magnesium acetate concentration 0.3 g / L
The resultant was immersed in 6 L of an aqueous solution at room temperature for 6 hours. After immersion,
The solution was drained to obtain EVOH pellets having a water content of 55% by weight.

EVOH and a boronic acid-modified resin were blended in the same manner as in Example 7 except that the obtained water-containing EVOH pellets were introduced into the same extruder as shown in FIG. As a result, the discharged strand foamed, and stable sampling could not be performed. Tables 1 to 4 show details such as the extrusion conditions, the composition of the processing solution, and the analysis results of the pellets.

(Table 1) Extrusion conditions: First extruder ―――――――――――――――――――――――― EVOH Trace component Resin Water content ( %) Amount Aqueous solution Temperature Injection Discharge (kg / hr) (L / hr) (° C) Before and after ――――――――――――――――――――――― -Example 1 10 0.25 130 50 20 Example 2 10 0.25 130 50 20 Example 3 10 0.25 130 50 20 Example 4 10 0.25 130 50 20 Example 5 10 0.25 130 50 20 Example 6 10 0.25 130 50 20 Example 7 10 0.25 130 50 20 Example 8 10 0.25 130 50 20 ――――――――――――――――――――――――――――: Second extruder ― ――――――――――――――――――――――――――――――――― EVOH Component B Resin Moisture content (%) Charge amount Type Addition amount Compounding amount Temperature input Discharge (kg / hr) (kg / hr) (parts by weight) (° C) Before and after ――――――――――――――――― ―――――――――――――――― Example 1 6.25 Polyurethane (133) 2 40 140 20 15 Example 2 6.25 EVOH (130) 0.25 5 130 20 19 Example 3 6.25 EVOH (140) 1 20 130 20 17 Example 4 6.25 EVOH (165) 5 100 130 20 17 Example 5 6.25 LDPE (106) 1 20 130 20 17 Example 6 6.25 BR-VLDPE (90) 0.5 10 130 20 19 Example 7 6.25 BR-VLDPE (90) 1 20 130 20 17 Example 8 6.25 BR-VLDPE (90) 1.5 30 140 20 16 Comparative Example 1 10 Polyurethane (133) 4 40 250 0.1 0.1 Comparative Example 2 10 BR-VLDPE (90) 3 30 250 0.1 0.1 Comparative Example 3 10 BR-VLDPE (90) 0.9 20 130 55 50 ――――――――――――――――――――――――――――――― --- The numerical value given to the resin type is the flow start temperature (polyurethane) or melting point (others).-The compounding amount is the compounding amount of the component with respect to 100 parts by weight of EVOH. 99.5 mol Charged amount of) the weight-Comparative Examples volatiles inclusive of the EVOH is used only the second extruder

(Table 2) Composition of treatment solution ―――――――――――――――――――――――――――――――― Acetate Boric acid Phosphate compound Alkali metal salt Alkaline earth metal salt (g / L) (g / L) (g / L) (g / L) (g / L) ――――――――――――――――― ――――――――――――――――― Example 1 5 ― 2.8 9.2 6.0 Example 2 2 30 0.6 ― ― Example 35 5 ― 2.8 9.2 6.0 Example 4 5 ― 2.8 9.2 6.0 Example 5 5-2.8 9.2 6.0 Example 6 5-2.8 9.2 6.0 Example 7 5-2.8 9.2 6.0 Example 8 5-2.8 9.2 6.0 Comparative Example 1 0.4-0.1 0.4 0.3 Comparative Example 2 0.4-0.1 0.4 0.3 Comparative Example 3 0.4 ― 0.1 0.4 0.3 ―――――――――――――――――――――――――――――――― ・ Phosphate compound is KH ₂ PO ₄・The alkali metal salt is NaOAc. The alkaline earth metal salt is Mg (OAc) ₂

(Table 3) Composition of resin composition ―――――――――――――――――――――――――――――――― Acetate Boric acid Phosphoric acid Compound Alkali metal salt Alkaline earth metal salt (ppm) (ppm) (ppm) (ppm) (ppm) ―――――――――――――――――――――――――― ―――――――― Example 1 200 ― 60 K: 20 Na: 80 Mg: 30 Example 2 100 270 20 K: 6 ― Example 3 190 ― 60 K: 20 Na: 80 Mg: 30 Example 4 120-40 K: 15 Na: 50 Mg: 20 Example 5 240-80 K: 30 Na: 100 Mg: 40 Example 6 270-90 K: 40 Na: 120 Mg: 50 Example 7 240-80 K : 30 Na: 100 Mg: 40 Example 8 210 ― 70 K: 30 Na: 90 Mg: 40 Comparative Example 1 300 ― 100 K: 40 Na: 130 Mg: 50 Comparative Example 2 300 ― 100 K: 40 Na: 130 Mg: 50 Comparative Example 3 240 ― 80 K: 30 Na: 100 Mg: 40 ―――――――――――――――――――――――――――――――― ―― ・ Boric acid concentration is equivalent to boron ・ Phosphate compound concentration is Down acid radical in terms of value and the alkali metal salt concentration of the alkali metal in terms of value and the alkaline earth metal salt concentration of the alkaline earth metal in terms of value

(Table 4) Extrusion stability ―――――――――――――――――――――――――― Strand stability Pellet shape ―――――― ―――――――――――――――――――――― Example 1 good good example 2 good good example 3 good good example 4 good good example 5 good good example 6 Good Good Example 7 Good Good Example 8 Good Good Comparative Example 1 Failure due to multiple cuts due to miscuts Comparative Example 2 Failure due to multiple cuts due to miscuts Comparative Example 3 Difficult due to multiple cuts due to cutout ―――――――― ――――――――――――――――――――

In each of the examples, the stability of the strand obtained from the first extruder was excellent, and the shape of the pellet obtained by cutting was also good.

[0138]

As described above in detail, according to the present invention, a small quantity and variety of EVOH can be efficiently and stably produced while avoiding loss due to brand switching. EVO
In view of the diversification of uses of H, the utility value of the present invention in the technical field is extremely high.

[Brief description of the drawings]

FIG. 1 is a side view showing a barrel and a screw of a twin-screw extruder of a first extruder that can be used for carrying out an embodiment of the present invention.

FIG. 2 is a side view showing a barrel and a screw of a twin-screw extruder of a second extruder that can be used for carrying out one embodiment of the present invention.

[Explanation of symbols]

1, 11 Raw material supply unit 2 Dewatering unit 3 Vent port 4 Trace component addition unit 5, 15 Temperature sensor 7a, 7b, 7c, 17a, 17c Full flight screw unit 8a, 8b, 18 Reverse flight screw unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 29/04 C08L 29/04 B 101/00 101/00 (72) Inventor Takaharu Kawahara Coast of Okayama City, Okayama Prefecture 1-2-1, Kuraray Co., Ltd. (72) Inventor Toshio Tsuboi 1-2-1, Kaigandori, Okayama-shi, Okayama Prefecture F-term in Kuraray Co., Ltd. 4F070 AA13 AA26 AA28 AA53 AA54 AB01 AC12 AC20 AC40 FA02 FA17 FB07 FC05 4J002 BB062 BB101 BB202 BB232 BE022 BE031 BF032 CK022 CL032 DH026 DH036 DK006 EF036 EF066 EF096 EG026 EG036 FD017 FD028 FD059 FD079 FD109 FD139 GG02

Claims (12)

[Claims] 1. The method according to claim 1, wherein the water content extruded from the first extruder is 5
-40% by weight of at least a part of an ethylene-vinyl alcohol copolymer resin (component A) and an additional component (component B)
And introducing the mixture into a second extruder, melt-kneading the mixture, and then discharging the mixture, wherein the resin composition is ethylene-vinyl alcohol copolymer resin composition. 2. The process for producing an ethylene-vinyl alcohol copolymer resin composition according to claim 1, wherein components (component C) other than components A and B are introduced into the first extruder. 3. Component C is a carboxylic acid, a boron compound,
The method for producing an ethylene-vinyl alcohol copolymer resin composition according to claim 2, wherein the resin composition is at least one selected from a phosphate compound, an alkali metal salt, and an alkaline earth metal salt. 4. Feeding water to the first extruder, removing water from the first extruder, or supplying water to the first extruder and water from the first extruder. The method for producing an ethylene-vinyl alcohol copolymer resin composition according to any one of claims 1 to 3, wherein the water content of the resin in the first extruder is adjusted by combining removal with the resin. 5. The extruder according to claim 1, wherein a part of the pellets obtained by cutting the ethylene-vinyl alcohol copolymer resin discharged from the first extruder is introduced into the second extruder. A method for producing an ethylene-vinyl alcohol copolymer resin composition of the above. 6. The ethylene-vinyl alcohol copolymer resin composition according to claim 1, wherein the water content of the resin composition immediately after being discharged from the second extruder is 5 to 40% by weight. Manufacturing method. 7. The temperature of the molten resin in the second extruder is 70
The method for producing an ethylene-vinyl alcohol copolymer resin composition according to any one of claims 1 to 6, wherein the temperature is from 170 to 170C. 8. The method for producing an ethylene-vinyl alcohol copolymer resin composition according to claim 1, wherein the amount of the component B is 0.01 to 200 parts by weight based on 100 parts by weight of the component A. 9. The method for producing an ethylene-vinyl alcohol copolymer resin composition according to claim 1, wherein the component B is a resin. 10. The method for producing an ethylene-vinyl alcohol copolymer resin composition according to claim 9, wherein at least one of the melting point and the flow start temperature of the component B is 170 ° C. or lower. 11. The ethylene-vinyl alcohol copolymer resin composition discharged from the second extruder according to any one of claims 1 to 10 is cut into pellets, and then has a water content of 1% by weight. %. The method for producing pellets of the ethylene-vinyl alcohol copolymer resin composition, wherein the pellets are dried until the amount becomes less than or equal to%. 12. A pellet obtained by cutting the ethylene-vinyl alcohol copolymer resin composition discharged from the second extruder by the method according to claim 5, and a pellet obtained by cutting the pellet obtained from the first extruder. A method for producing pellets of an ethylene-vinyl alcohol copolymer resin composition, characterized in that the remainder is dried until the water content becomes 1% by weight or less.