JP2001164070A - Resin composition comprising ethylene-vinyl alcohol copolymer excellent in low odor - Google Patents

Abstract

(57) [abstract] (with correction) [PROBLEMS] To provide excellent appearance, excellent long-run property during melt molding, little coloring during recovery, excellent low odor, and interlayer adhesion when formed into a laminate. Provided is a resin composition comprising an ethylene-vinyl alcohol copolymer having excellent resistance. A resin composition comprising an ethylene-vinyl alcohol copolymer, wherein the MFR of the resin composition when heated at 220 ° C. under a nitrogen atmosphere.
(230 ° C., 10.9 kg load) shows a local minimum value within 10 hours from the start of heating, and shows a local maximum value (MFRmax) within 100 hours after showing the local minimum value. Containing 4 μmol / g and formula (1)
And a resin composition satisfying (2). 0.5 ≦ MFRmax / MFR ≦ 45 (1) 0.1 ≦ (a1) / (A) ≦ 1.0 (2) where, MFR0: MF of the resin composition that has not been subjected to heat treatment
R (A): Total content of carboxylic acid (A) and its salt (μ
mol / g) (a1): Content of carboxylic acid (a1) having a molecular weight of 75 or more and its salt (μmol / g)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is characterized by having less coloring, fish eyes (gels / bubbles), streaks, etc., excellent appearance, excellent long-running properties during melt molding, little coloring during recovery, and low odor. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition comprising an ethylene-vinyl alcohol copolymer which is excellent and has excellent interlayer adhesion when formed into a laminate, and a multilayer structure using the same.

[0002]

2. Description of the Related Art Ethylene-vinyl alcohol copolymer (hereinafter sometimes abbreviated as EVOH) is a useful polymer material excellent in oxygen shielding property, oil resistance, non-charging property, mechanical strength and the like. Widely used as various packaging materials such as sheets and containers. Such packaging materials are usually manufactured by melt molding, and have a long run property during melt molding (a molded article free of fish eyes and stripes can be obtained even when molding for a long time), and the appearance of the molded article (less colored) And a molded product in which generation of fish eyes is not observed. In recent years, recyclability has also become an important issue. Even when an EVOH molded product is collected, melt-molded again, and the heat history is repeated, the recoverability (recovered E
There is a demand for EVOH that has good VOH moldability) and has little coloration during recovery. Further, generally, in order to impart mechanical strength, moisture resistance, heat sealability, and the like, it is co-extruded through a base material such as a polyolefin resin and an adhesive layer to form a laminate. The interlayer adhesion of the body is also important. That is, it is necessary to sufficiently satisfy the appearance of the molded product, the long-run property during melt molding, the recoverability, and the interlayer adhesion of the laminate.

Therefore, as a countermeasure, the following proposals have been made to produce an excellent molded product by treating an ethylene-vinyl alcohol copolymer with various acids or metal salts.

[0004] For example, (1) To improve the long run property and the appearance typified by gel buttes, 0.0005 to 0.05% by weight of a metal salt of Group II of the periodic table (in terms of metal element) ), Containing 0.002 to 0.2% by weight of an acid having a pKa of 3.5 or more and a boiling point of 180 ° C or more and 0.01 to 0.2% by weight of an acid having a pKa of 3.5 or more and a boiling point of 120 ° C or less; An EVOH composition exhibiting specific flow characteristics has been disclosed (JP-A-64-66262).
(2) An EVOH composition containing a hydroxycarboxylic acid and / or a salt thereof, an alkali metal salt, an alkaline earth metal salt, a phosphate, and a boron compound in order to improve coloring, appearance, and interlayer adhesion is disclosed. (Japanese Unexamined Patent Publication No.
67898). Further, the publication discloses Example 1 as lactic acid 2,000 pp per 100 parts by weight of EVOH.
m (as lactic acid root), resin containing 350 ppm of alkali metal salt (in terms of metal element), 50 ppm of alkaline earth metal (in terms of metal element), 30 ppm of phosphorus compound (in terms of phosphorus), 40 ppm of boron compound (in terms of boron element) A composition is disclosed.

[0005]

However, in the techniques disclosed in the above (1) and (2), the appearance of a molded article, long run property at the time of melt molding, interlayer adhesion of a laminate, recyclability, etc. Nothing that simultaneously satisfies low odor has been found, and at the present time there is a demand for molded products with advanced functions and quality and improvement of the working environment when manufacturing them, they are fully satisfactory. At present, it has not yet reached a level that can be achieved.

[0006] In order to improve the working environment during production of resin compositions and melt molding, EVOH having excellent low odor is required, but the above-mentioned prior art does not describe odor.

[0007]

The above-mentioned problems are solved by the resin composition of the present invention. That is, when the resin composition is a resin composition comprising an ethylene-vinyl alcohol copolymer and heated at 220 ° C. in a nitrogen atmosphere, the MFR of the resin composition (230 ° C .;
9 kg load) shows a minimum value within 10 hours from the start of heating, and a maximum value (MF) within 100 hours after showing the minimum value.
Rmax) by providing a resin composition characterized by containing 0.05 to 4 μmol / g of the carboxylic acid (A) and satisfying the following formulas (1) and (2). Will be resolved. 0.5 ≦ MFRmax / MFR ≦ 45 (1) 0.1 ≦ (a1) / (A) ≦ 1.0 (2) where MFRmax: when the resin composition is heated at 220 ° C. under a nitrogen atmosphere. , MFR of the resin composition (230 ° C, 1
Maximum value of 0.9 kg load) MFR0: MF of resin composition not subjected to heat treatment
R (230 ° C., 10.9 kg load) (A): Total content of carboxylic acid (A) and its salt (μ)
mol / g) (a1): Content of carboxylic acid (a1) having a molecular weight of 75 or more and its salt (μmol / g)

In a preferred embodiment, the resin composition of the present invention comprises an alkali metal salt (B) in an amount of 50 to 500 in terms of a metal element.
ppm.

In a preferred embodiment, the resin composition of the present invention comprises an alkaline earth metal salt (C) in an amount of 10 to 1 in terms of a metal element.
It contains 20 ppm.

In a preferred embodiment, the resin composition of the present invention comprises a phosphate compound (D) in an amount of 10 to 500 p in terms of a phosphate group.
pm.

In a preferred embodiment, the resin composition of the present invention comprises a boron compound (E) in an amount of 50 to 200 in terms of elemental boron.
It contains 0 ppm.

In a preferred embodiment, the resin composition of the present invention satisfies the following formula (3). [B (μmol / g) + C (μmol / g)] / [A (μmol / g) + D (μmol / g)] = 2-9 (3) where A: carboxylic acid per unit weight of the resin composition Content of (A) (μmol / g) B: Content of alkali metal salt (B) per unit weight of resin composition (μmol / g) C: Alkaline earth metal salt per unit weight of resin composition Content of (C) (μmol / g) D: Phosphate compound (D) per unit weight of resin composition
Content (μmol / g)

In a preferred embodiment, the resin composition of the present invention contains 0.005 to 1 parts by weight of a lubricant based on 100 parts by weight of EVOH.
Parts by weight.

In a preferred embodiment, the pellets comprising the resin composition of the present invention are obtained by adhering 0.005 to 0.5 parts by weight of a lubricant to 100 parts by weight of the resin composition on the outer surface of the pellets. .

[0015] The present invention also relates to a multilayer structure obtained by laminating a thermoplastic resin on at least one surface of a layer comprising the above resin composition.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The EVOH used in the present invention is preferably obtained by saponifying an ethylene-vinyl acetate copolymer, and among them, the ethylene content is 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 65 mol%, more preferably 20 mol%.
Preferably, it is between about 65 mol% and optimally between 25 and 60 mol%. Further, the saponification degree of the vinyl acetate component is preferably 80% or more, and more preferably 95% or more, and further preferably 99% or more, from the viewpoint of obtaining a molded article having excellent gas barrier properties. Ethylene content of 70
If it exceeds mol%, the barrier properties and printability may be insufficient. If the saponification degree is less than 80%, the barrier properties, thermal stability, and moisture resistance may be deteriorated.

On the other hand, EVOH having an ethylene content of 3 to 20 mol% is suitably used as EVOH having water solubility, and such an EVOH aqueous solution has excellent barrier properties and coating stability, and is an excellent coating material. Used.

When copolymerizing ethylene and vinyl acetate, other fatty acid vinyl esters (such as vinyl propionate and vinyl pivalate) can also be used in combination. EVOH can contain 0.0002 to 0.2 mol% of a vinylsilane compound as a copolymerization component. Here, as the vinylsilane-based compound, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxy-ethoxy) silane,
γ-methacryloxypropylmethoxysilane. Among them, vinyltrimethoxysilane and vinyltriethoxysilane are preferably used.

Hereinafter, a method for producing EVOH will be specifically described. The polymerization of ethylene and vinyl acetate is not limited to solution polymerization, but may be any of solution polymerization, suspension polymerization, emulsion polymerization, bulk polymerization, and may be any of a continuous system and a batch system. For example, the polymerization conditions in the case of batch type solution polymerization are as follows.

Solvent: Alcohols are preferred, but other organic solvents (such as dimethyl sulfoxide) that can dissolve ethylene, vinyl acetate and ethylene-vinyl acetate copolymer can also be used. As the alcohols, methyl alcohol, ethyl alcohol, propyl alcohol, n-butyl alcohol, t-butyl alcohol and the like can be used, and methyl alcohol is particularly preferable. Catalyst; 2,2-azobisisobutyronitrile, 2,2-
Azobis- (2,4-dimethylvaleronitrile), 2,
2-azobis- (4-methyl-2,4-dimethylvaleronitrile), 2,2-azobis- (4-methoxy-2,
4-dimethylvaleronitrile), 2,2-azobis-
Azonitrile-based initiators such as (2-cyclopropylpropionitrile) and isobutyryl peroxide, cumyl peroxy neodecanoate, diisopropyl peroxy carbonate, di-n-propyl peroxy dicarbonate, t-butyl peroxy neo Decanoate, lauroyl peroxide, benzoyl peroxide,
Organic peroxide-based initiators such as t-butyl hydroperoxide and the like can be used. Temperature: 20-90 ° C, preferably 40-70 ° C. Time; 2 to 15 hours, preferably 3 to 11 hours. Polymerization rate; 10 to 90% based on the charged vinyl ester;
Preferably 30-80%. Resin content in solution after polymerization; 5 to 85%, preferably 20
~ 70%. Ethylene content in the copolymer; preferably 3 to 70 mol%, more preferably 25 to 60 mol%.

It is to be noted that, in addition to ethylene and vinyl acetate, monomers copolymerizable therewith, for example, α-olefins such as propylene, isobutylene, α-octene, α-dodecene; acrylic acid, methacrylic acid, crotonic acid, maleic acid Acids, unsaturated acids such as itaconic acid or anhydrides, salts or mono- or dialkyl esters; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; ethylene sulfonic acid, allyl sulfonic acid; Olefin sulfonic acid such as methallyl sulfonic acid or a salt thereof; alkyl vinyl ethers, vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride, and the like can be coexisted in small amounts.

After the polymerization for a predetermined time has reached a predetermined polymerization rate, a polymerization inhibitor is added if necessary, and unreacted ethylene gas is removed by evaporation, and then unreacted vinyl acetate is expelled. As a method of driving out unreacted vinyl acetate from the ethylene-vinyl acetate copolymer from which ethylene has been removed by evaporation,
For example, the copolymer solution is continuously supplied at a constant rate from the top of the tower filled with Raschig rings, and an organic solvent vapor such as methanol is blown from the bottom of the tower and an organic solvent such as methanol and unreacted vinyl acetate are blown from the top of the tower. A method of distilling out the mixed vapor and taking out the copolymer solution from which unreacted vinyl acetate has been removed from the bottom of the column is adopted.

An alkali catalyst is added to the copolymer solution from which unreacted vinyl acetate has been removed to saponify the vinyl acetate component in the copolymer. The saponification method can be either a continuous type or a batch type. As the alkali catalyst, sodium hydroxide, potassium hydroxide, alkali metal alcoholate and the like are used. For example, the saponification conditions in the case of the batch system are as follows. Concentration of the copolymer solution; 10 to 50%. Reaction temperature; Amount of catalyst used: 0.02 to 0.6 equivalent (per vinyl acetate component). Time; 1-6 hours. Although the degree of saponification after the saponification reaction varies depending on the purpose, it is preferably 80% or more of the vinyl acetate component, more preferably 95%.
Above, more preferably 99% or more. The saponification degree can be arbitrarily adjusted depending on the conditions.

Since the ethylene-vinyl alcohol copolymer after the reaction contains an alkali catalyst, by-product salts, and other impurities, it is preferable to remove these by neutralizing and washing as necessary.

The resin composition of the present invention can be used under nitrogen atmosphere.
When heated at 20 ° C., the MFR (230
(1 ° C., 10.9 kg load) shows a minimum value within 10 hours from the start of heating, and shows a maximum value (MFRmax) within 100 hours after showing the minimum value, and satisfies the following formula (1). It is extremely important that the use of such a structure makes it possible to use EVOH, which is excellent in low odor, long run properties, appearance of molded products, recoverability, color resistance during recovery, and interlayer adhesion during melt molding for the first time. A resin composition can be obtained. 0.5 ≦ MFRmax / MFR0 ≦ 45 (1) where, MFRmax: MFR of the resin composition when the resin composition is heated at 220 ° C. under a nitrogen atmosphere (230 ° C., 1
Maximum value of 0.9 kg load) MFR0: MF of resin composition not subjected to heat treatment
R (230 ° C., 10.9 kg load) The resin composition comprising the EVOH of the present invention exhibiting such a melting behavior has a small amount of resin attached to the die during melt molding. Further, even during extremely long-time melt molding, it is possible to suppress gels and bumps of a molded product (such as a film). That is, the resin composition comprising the EVOH of the present invention is extremely excellent in long-run property.

On the other hand, when the resin composition composed of EVOH does not have the above-mentioned structure (Comparative Example 4: see FIG. 1), not only the effect of reducing the amount of die attached is not obtained but also the continuous operation for a long period of time. It is clear that the number of generated gels and butters increases when the above is performed.

Further, as a result of detailed studies by the present inventors, it is clear that the resin composition comprising EVOH having no above-mentioned structure may rapidly increase the frequency of occurrence of gels and butters during long-term operation. Became. This rapid increase in the frequency of gel spots is not permanent, and usually, after a few minutes to several tens of minutes have passed since the frequency of the gel spots increased rapidly, the normal level of gel spots was resumed. Although the frequency of occurrence reverts to the frequency of occurrence, the appearance of the molded article when the frequency of occurrence of gel / bubbles suddenly increases is poor, and a product which can withstand practical use cannot be usually obtained. However, by using the resin composition of the present invention developed by the present inventors, it has become possible to effectively suppress a rapid increase in the frequency of occurrence of gel and butter even during long-time melt molding. As described above, by using the resin composition of the present invention, long-time molding can be performed without problems even in applications requiring an extremely high appearance, such as a film, and productivity can be improved. From this viewpoint, the present invention is significant.

The resin composition comprising the EVOH of the present invention comprises:
The following expression (1) is satisfied. 0.5 ≦ MFRmax / MFR0 ≦ 45 (1) where, MFRmax: MFR of the resin composition when the resin composition is heated at 220 ° C. under a nitrogen atmosphere (230 ° C., 1
Maximum value of 0.9 kg load) MFR0: MF of resin composition not subjected to heat treatment
R (230 ° C., 10.9 kg load) The lower limit of MFRmax / MFR0 is more preferably 0.7.
And more preferably 1. Also, MFRma
The upper limit of x / MFRO is more preferably 35, more preferably 25, even more preferably 20,
Optimally it is 10. When the value of MFRmax / MFR0 is in the above range, the amount of the thermally degraded resin adhered to the molding machine die during the melt molding of the resin composition and the generation of gel / bubbles of the molded product are small, and the generation of gel / bubbles is generated. It is possible to obtain a resin composition composed of EVOH which is excellent in coloring resistance and whose frequency fluctuation is suppressed.

If the value of MFRmax / MFR0 is less than 0.5, the amount of resin adhered to the molding machine die increases, the long-run property deteriorates, and the effect of suppressing the fluctuation in the frequency of occurrence of gels and bumps is insufficient. It becomes something. Also, MFRmax
It is clear from Comparative Example 5 that when the value of / MFR0 exceeds 45, coloring due to decomposition of EVOH becomes remarkable and the appearance becomes poor.

The carboxylic acid (A) used in the resin composition of the present invention includes saturated aliphatic carboxylic acids such as acetic acid and propionic acid, unsaturated aliphatic carboxylic acids such as oleic acid, and hydroxy acids such as glycolic acid and lactic acid. carboxylic acid,
Examples thereof include aromatic carboxylic acids such as benzoic acid, and their pKa at 25 ° C. is preferably 3.5 or more. If the pKa at 25 ° C. is less than 3.5, it may be difficult to control the pH of the resin composition comprising EVOH, and the coloring resistance and interlayer adhesion may be unsatisfactory.

The resin composition of the present invention contains 0.05 to 4 μmol / g of the carboxylic acid (A), and has the following formula (2)
To be satisfied. 0.1 ≦ (a1) / (A) ≦ 1.0 (2) where (A) is the total content of the carboxylic acid (A) and its salt (μ)
mol / g) (a1): Content of carboxylic acid (a1) having a molecular weight of 75 or more and its salt (μmol / g)

Examples of the carboxylic acid (a1) having a molecular weight of 75 or more used in the present invention include succinic acid, adipic acid, benzoic acid, capric acid, lauric acid, glycolic acid and lactic acid. When a dicarboxylic acid such as that described above is used, there is a possibility that gels and bumps are likely to occur during molding. When a hydroxycarboxylic acid such as glycolic acid or lactic acid is used, the problems described above do not occur, and it is preferable from the viewpoint of excellent water solubility. Among them, lactic acid is particularly preferable.

In particular, a carboxylic acid having a molecular weight of 75 or more (a
When lactic acid is used as 1), it is preferable because it has excellent water solubility as described above and has extremely low volatility as compared with acetic acid. When producing pellets made of the EVOH resin composition, it is usually necessary to dry the pellets in a water-containing state. In this drying step, too, the use of lactic acid greatly suppresses the volatilization of the acid component, thereby making the pellets more stable. Quality products can be produced. Also, lactic acid (25
Since pKa at 3.degree. C. = 3.858) is a stronger acid than acetic acid (pKa at 4.degree. C. = 4.756), the amount of acid used can be reduced. Since lactic acid has low volatility and requires a small amount of use, it is possible to significantly reduce the outflow of an acid component out of the system in the production process of the EVOH resin composition, thereby reducing the burden on the worker. be able to. Further, the load on the environment around production facilities (such as factories) can be significantly reduced.

As the carboxylic acid (a1) having a molecular weight of 75 or more, a carboxylic acid having a molecular weight of 80 or more is more preferable.
A molecular weight of 85 or more is more preferred, and a molecular weight of 90 or more is particularly preferred. By using a carboxylic acid having a high molecular weight, a volatile component at the time of molding can be reduced, and a resin composition having excellent low odor and long run properties can be obtained.

Carboxylic acid (A) in the resin composition of the present invention
Is 0.05 to 4 μmol / g. When the content of the carboxylic acid (A) is less than 0.05 μmol / g, coloring at the time of melting is remarkable. If it exceeds 4 μmol / g, the effect of improving the low odor and the effect of improving the adhesive force with the adhesive resin in coextrusion molding become insufficient, and the amount of die attached tends to increase. The lower limit of the content of the carboxylic acid (A) is preferably at least 0.1 μmol / g, and more preferably at least 0.2 μmol / g. Further, the upper limit of the content of the carboxylic acid (A) is preferably 3 μmol / g or less, more preferably 2.5 μmol / g or less, further preferably 2 μmol / g or less, and most preferably 2 μmol / g or less. 1.5 μmol
/ G or less.

As described above, the resin composition of the present invention satisfies the following formula (2). 0.1 ≦ (a1) / (A) ≦ 1.0 (2) where (A) is the total content of the carboxylic acid (A) and its salt (μ)
mol / g) (a1): Content of carboxylic acid (a1) having a molecular weight of 75 or more and its salt (μmol / g)

The carboxylic acid (A) in the resin composition of the present invention
And the ratio of the content (μmol / g) of the carboxylic acid (a1) having a molecular weight of 75 or more to the total content (μmol / g) of the salt thereof, that is, (a1) / (A) in the above formula (2) Is 0.1 or more. If the ratio is less than 0.1, the effect of improving low odor and long run properties will be insufficient. (A) in the above equation (2)
The lower limit of 1) / (A) is preferably 0.5 or more, more preferably 0.7 or more, particularly preferably 0.9 or more, and most preferably 0.98 or more.

It is preferable that the resin composition of the present invention contains the alkali metal salt (B) in an amount of 50 to 500 ppm in terms of a metal element from the viewpoint of improving the adhesiveness.
More preferably, the content is 300 ppm. The alkali metal salt (B) is not particularly limited, but preferred examples thereof include a sodium salt and a potassium salt. The anionic species of the alkali metal salt (B) is not particularly limited, but an acetate anion, a lactate anion and a phosphate anion are exemplified as suitable anion species, and among them, a lactate anion is preferred.

If the content of the alkali metal salt (B) is less than 50 ppm, the effect of improving the adhesiveness may be unsatisfactory. If the content exceeds 500 ppm, the effect of improving the coloring resistance upon melting is insufficient. May be caused.

The resin composition of the present invention preferably contains an alkaline earth metal salt (C) in an amount of 10 to 120 ppm, more preferably 20 to 100 ppm, in terms of a metal element. By containing the alkaline earth metal salt in such a range, it becomes easy to control the MFR over time of the resin composition composed of EVOH, and the inside of a molding machine die of a thermally degraded resin during melt molding using the resin composition. It is possible not only to reduce the amount of adhesion to the surface, but also to improve the long-run property. If the content of the alkaline earth metal salt is less than 10 ppm, the effect of improving long-run properties may be unsatisfactory, and if it exceeds 120 ppm, coloring during melting is remarkable.

The alkaline earth metal salt (C) is not particularly restricted but includes magnesium salt, calcium salt, barium salt, beryllium salt and the like, and magnesium salt and calcium salt are particularly preferred. The anionic species of the alkaline earth metal salt (C) is not particularly limited,
Acetate anion, lactate anion and phosphate anion are exemplified as suitable anion species, among which lactate anion is preferred.

When the alkaline earth metal salt (C) in the resin composition of the present invention is a magnesium salt, its preferable content is 10 to 60 ppm, more preferably 20 to 50 ppm, in terms of a metal element. Further, when the alkaline earth metal salt (C) in the resin composition is a calcium salt, a suitable content is 20 to 120 ppm, more preferably 40 to 100 ppm, in terms of a metal element.

Since the resin composition of the present invention contains a carboxylic acid (a1) having a molecular weight of 75 or more and a high boiling carboxylic acid in an appropriate ratio, it has excellent coloration resistance and appearance even during long-time melt molding. A molded article is obtained. For this reason, in some cases, it is preferable not to add the phosphoric acid compound (D) in view of cost advantages at the time of production and simplicity of production. Can be further improved. In particular, when a continuous operation for a long period of time of several days is performed, or when heat history is accumulated (when a molded product is collected, etc.), contribution to the effect of improving the coloring resistance is large.

The addition amount of the phosphoric acid compound (D) is preferably from 10 to 500 ppm in terms of phosphate groups. The content of the phosphate compound (D) is 10 to 200 p in terms of phosphate group.
pm, more preferably 20
１５０150 ppm. By containing the phosphoric acid compound in such a range, it is possible to obtain a resin composition which is less colored, has excellent long-run properties and gives a good appearance of a molded article. If the content of the phosphoric acid compound (D) is less than 10 ppm, the effect of improving the color resistance during melt molding may be insufficient, and the appearance may be reduced. In particular, when the heat history is repeated, the tendency is remarkable, so that the resin composition may have poor recoverability. 500 ppm
If the ratio exceeds the above range, the occurrence of gel and butter in the molded product becomes remarkable, and the appearance is reduced. Examples of the phosphoric acid compound (D) include various acids such as phosphoric acid and phosphorous acid, and salts thereof.
It is not limited to these. The phosphate may be contained in any form of a first phosphate, a second phosphate, and a third phosphate, and the cation species is not particularly limited. Preferred are alkali metal salts and alkaline earth metal salts. Among them, it is preferable to add the phosphate compound (D) in the form of sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, and dipotassium hydrogen phosphate.

The boron compound (E) is added to the resin composition of the present invention in an amount of 50 to 2000 ppm in terms of boron element.
It is also preferable to include them. Examples of the boron compound (E) include, but are not limited to, boric acids, borate esters, borates, and borohydrides. Specifically, the boric acids include orthoboric acid, metaboric acid, tetraboric acid, and the like, and the borate esters include triethyl borate, trimethyl borate, and the like.
Examples of the borate include alkali metal salts, alkaline earth metal salts, and borax of the above-mentioned various boric acids. Of these compounds, orthoboric acid (hereinafter sometimes simply referred to as boric acid) is preferred.

When a boron compound is added to a resin composition composed of EVOH, the melt viscosity can be increased even when EVOH having a low degree of polymerization is used. It is possible to suppress the generation of gel and butter and improve the long-run property as compared with EVOH. When the resin composition of the present invention contains a boron compound (E), the effect of reducing the amount of die attached may decrease slightly during long-time melt molding such as several days. It is possible to extremely effectively suppress the generation of gel and butter. The lower limit of the content of the boron compound (E) is preferably 50 ppm or more, more preferably 100 ppm, in terms of boron element.
And more preferably 150 ppm or more. Further, the upper limit of the content of the boron compound (E) is preferably 1500 ppm or less in terms of boron element,
More preferably, it is 1000 ppm or less. When the content of the boron compound (E) is less than 50 ppm, the generation of gel / bubbles may increase as the molding time becomes longer. Therefore, when the continuous operation is performed for a long period of time, the appearance of the molded article deteriorates. There is a fear. If the content of the boron compound (E) exceeds 2,000 ppm, gelation is likely to occur, resulting in poor moldability.

In the present invention, when the resin composition of the present invention satisfies the following formula (3), the effects of the present invention can be more remarkably obtained, which is preferable. [B (μmol / g) + C (μmol / g)] / [A (μmol / g) + D (μmol / g)] = 2-9 (3) where A: carboxylic acid per unit weight of the resin composition Content of (A) (μmol / g) B: Content of alkali metal salt (B) per unit weight of resin composition (μmol / g) C: Alkaline earth metal salt per unit weight of resin composition Content of (C) (μmol / g) D: Phosphate compound (D) per unit weight of resin composition
Content (μmol / g)

By increasing the contents of the alkali metal salt (B) and the alkaline earth metal (C) in the resin composition comprising EVOH, the adhesiveness of the resin composition and the effect of reducing the amount of die attached are improved. , MFRmax / MFRO generally increase. However, the addition of excess alkali metal salt (B) and alkaline earth metal salt (C)
In addition to deteriorating the color resistance, the decomposition of the resin composition adversely affects the low odor.

On the other hand, by increasing the content of the carboxylic acid (A) and the phosphoric acid compound (D) in the resin composition composed of EVOH, it is possible to improve the color fastness of the molded product, and MFRmax / MFRO is generally Decline. In addition, long run properties can be improved by adding appropriate amounts of the carboxylic acid (A) and the phosphoric acid compound (D). However, the addition of excessive amounts of the carboxylic acid (A) and the phosphoric acid compound (D) rather causes an increase in gels and bumps, and further lowers the adhesiveness of the resin composition. As described above, the effects of the carboxylic acid (A), the alkali metal salt (B), the alkaline earth metal salt (C), and the phosphoric acid compound (D) on the properties of the resin composition are mutually related, By blending them in a well-balanced manner, a resin composition composed of EVOH that exhibits high performance in all aspects of low odor, long run property during melt molding, appearance, recovery, coloring resistance and interlayer adhesion. It is possible to get things.

Here, when the resin composition of the present invention satisfies the above expression (3), it is possible to obtain a resin composition highly balanced particularly in interlayer adhesion strength and appearance of a molded article. Become. [B (μmol / g) + C (μmol
/ G)] / [A (μmol / g) + D (μmol / g)] is less than 2, there is a possibility that the interlayer adhesion strength is reduced. There is a fear. [B (μmol / g) + C (μmol / g)] / [A (μ
mol / g) + D (μmol / g)] is more preferably 3 or more, and even more preferably 4 or more. The upper limit is more preferably 8 or less, and even more preferably 7 or less.

Also, the EVOH resin composition of the present invention includes:
It is also preferable to add 0.005 to 1 part by weight of a lubricant to 100 parts by weight of EVOH. By adding a lubricant, not only the amount of die attached can be reduced, but also a resin composition made of EVOH which is hardly colored at the time of recovery and has a good long-run property can be obtained. The effect of such a lubricant is particularly remarkable when the resin composition of the present invention contains a boron compound (E). Further, when the resin composition of the present invention contains a boron compound (E), the effect of suppressing the fluctuation in the frequency of occurrence of gels and buttes is slightly reduced when continuous melt molding is performed for an extremely long time. Sometimes. However, as a result of a detailed study performed by the present inventors, surprisingly, the EVOH resin composition comprising
It has been found that by adding 0.005 to 1 part by weight of a lubricant to 100 parts by weight, the effect of suppressing fluctuations in the frequency of occurrence of gel and butter can be maintained for an extremely long time.

The preferred content of the lubricant is 0.005 to 1 part by weight of the lubricant based on 100 parts by weight of the EVOH. If the lubricant content is less than 0.005 parts by weight with respect to 100 parts by weight of EVOH, the effect of adding the lubricant as described above may be insufficient, and if it exceeds 1 part by weight, surging may easily occur. And the extrusion stability may be degraded. The lower limit of the content of the lubricant is more preferably EVOH10.
0.01 parts by weight or more based on 0 parts by weight. Further, the upper limit of the content of the lubricant is more preferably 0.8 part by weight or less based on 100 parts by weight of EVOH, and still more preferably 0.1 part by weight.
It is at most 7 parts by weight, optimally at most 0.5 parts by weight.

The lubricant usable in the present invention is not particularly limited. For example, higher fatty acid amides, higher fatty acid metal salts (eg, calcium stearate), low molecular weight polyolefins (eg, low molecular weight polyethylene having a molecular weight of about 500 to 10,000, or Low-molecular-weight polypropylene and the like), but are not limited thereto. Among them, it is preferable to use higher fatty acid amides. Specifically, higher saturated fatty acid amides (eg, stearic acid amide, palmitic acid amide, lauric acid amide, etc.),
Examples include higher unsaturated fatty acid amides (eg, oleic acid amide, erucic acid amide, etc.), higher bis fatty acid amides (eg, ethylene bisstearic acid amide, methylene bisstearic acid amide, etc.). Here, the higher fatty acid means a fatty acid having 6 or more carbon atoms, and more preferably has 10 or more carbon atoms.

The form of the lubricant may be any of powder, solution, dispersion and the like, and is not particularly limited. Also, the content of the lubricant is not particularly limited, and a method of melt-mixing the resin composition and the lubricant, a method of extruding the solution after the saponification reaction to which the lubricant is added into a coagulating liquid in a strand form, a method of combining these methods Etc.

The resin composition pellets of the present invention also comprise pellets comprising the resin composition of the present invention, wherein 0.005 to 0.5 parts by weight of a lubricant is adhered to 100 parts by weight of the resin composition. Is suitable as an embodiment of the present invention. The lower limit of the amount of the lubricant attached to the pellets is more preferably at least 0.01 part by weight based on 100 parts by weight of EVOH. The upper limit of the amount of the lubricant attached to the pellet is more preferably EVOH10.
0.3 parts by weight or less, more preferably 0.2 parts by weight or less, and most preferably 0.1 part by weight or less with respect to 0 parts by weight. The amount of the lubricant adhering to the outer surface of the pellets made of the resin composition was 0.1 to 100 parts by weight of the resin composition.
If the amount exceeds 5 parts by weight, the feeding of the pellets to the extruder may not be stable. The method for producing such resin composition pellets is not particularly limited, but a method of dry blending the EVOH resin composition pellets with a lubricant is exemplified as a suitable method.

A suitable melt flow rate (MFR) of the resin composition comprising EVOH obtained in the present invention (190)
° C, measured under a load of 2160 g; melting point is 190 ° C
Those near or exceeding 190 ° C are measured at a plurality of temperatures above the melting point under a load of 2160 g, and the reciprocal of the absolute temperature is plotted as abscissa and the melt flow rate is plotted as ordinate (logarithm) on a semilogarithmic graph. The extrapolated value) is preferably 0.1 to 200 g / 10 min. It is. The lower limit of the MFR is more preferably 0.2 g / 10 min. And more preferably 0.5 g / 10 min. This is optimally 1 g / 10 min. That is all. Also, M
The upper limit of FR is more preferably 50 g / 10 min. Or less, more preferably 10 g / 10 min. Is the following,
Optimally, 7 g / 10 min. It is as follows. When the melt flow rate is smaller than the above range, the inside of the extruder is in a high torque state during molding and extrusion processing becomes difficult. Absent.

It is also possible to blend the resin composition of the present invention with EVOH having a different degree of polymerization, ethylene content and saponification degree in a range that does not impair the object of the present invention, followed by melt molding. In addition, within the range not impairing the object of the present invention, other various plasticizers, stabilizers, surfactants, coloring agents, ultraviolet absorbers, slip agents, antistatic agents, drying agents, crosslinking agents, etc. It is also possible to add appropriate amounts of metal salts, fillers, reinforcing agents such as various fibers, and the like.

It is also possible to mix an appropriate amount of a thermoplastic resin other than the resin composition 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, copolymer of ethylene and α-olefin having 4 or more carbon atoms, polyolefin Copolymer of ethylene and maleic anhydride, ethylene-vinyl ester copolymer, ethylene-acrylate ester copolymer, or modified polyolefin obtained by graft-modifying these with unsaturated carboxylic acid or a derivative thereof), various nylons (nylons) -6, nylon-6,6, nylon-6 / 6,6 copolymer), polyvinyl chloride, polyvinylidene chloride, polyester, polystyrene, polyacrylonitrile, polyurethane, polyacetal, and modified polyvinyl alcohol resin.

A carboxylic acid (A) and, if necessary, an alkali metal salt (B), an alkaline earth metal salt (C), a phosphoric acid compound (D) and a boron compound (E) are added to EVOH.
Is not particularly limited. For example, a method of immersing the EVOH in a solution in which the compound is dissolved,
A method of melting the EVOH and mixing the compound,
There is a method of dissolving VOH in an appropriate solvent and mixing the above compound.

Among them, a method in which EVOH is immersed in a solution of the above compound is desirable in order to exert the effects of the present invention more remarkably. This processing can be performed by either a batch method or a continuous method. At this time, the shape of the EVOH may be any shape such as powder, granule, sphere, and columnar pellet.

EVOH is converted to a carboxylic acid (A) and, if necessary, an alkali metal salt (B), an alkaline earth metal salt (C), a phosphoric acid compound (D) and a boron compound (E).
When immersed in a solution containing, the carboxylic acid (A) in the above solution, an alkali metal salt (B), an alkaline earth metal salt (C), a phosphoric acid compound (D) and a boron compound which are added as necessary. Each concentration of compound (E) is
There is no particular limitation. The solvent of the solution is not particularly limited, but is preferably an aqueous solution for reasons such as handling. The suitable range of the immersion time varies depending on the form of the EVOH, but in the case of pellets of about 1 to 10 mm, it is preferably 1 hour or more, preferably 2 hours or more.

In the immersion treatment of the above-mentioned various compounds in a solution, the immersion may be performed by dividing into a plurality of solutions or may be performed at once. Among them, it includes carboxylic acid (A), and further includes all of alkali metal salt (B), alkaline earth metal salt (C), phosphoric acid compound (D) and boron compound (E) which are added as needed. Treatment with a solution is preferred in terms of simplification of the process. When the treatment is performed by immersion in the solution as described above, drying is finally performed to obtain a target EVOH composition.

The obtained resin composition of the present invention is formed into various molded products such as films, sheets, containers, pipes and fibers by melt molding. These molded products can be crushed and molded again for the purpose of reuse. It is also possible to uniaxially or biaxially stretch films, sheets, fibers and the like. Examples of the melt molding method include extrusion molding, inflation extrusion, blow molding, melt spinning, and injection molding. The melting temperature varies depending on the melting point of the copolymer, etc.
About 50-270 degreeC is preferable.

As described above, the resin composition of the present invention has at least one layer of a molded product such as a film or sheet of the composition of the present invention, in addition to the production of a resin molded product containing only the resin composition as a single layer. It is often used practically as a multilayer structure. When the resin composition of the present invention 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, etc. But not limited thereto. Each layer may be a single layer or may be a multilayer in some cases.

The method for producing the above-mentioned multilayer structure is not particularly limited. For example, a method of melt-extruding a thermoplastic resin into a molded product (film, sheet, etc.) comprising the resin composition of the present invention, a method of co-extruding the resin composition of the present invention with another thermoplastic resin, a thermoplastic resin And a method of co-injecting a resin composition comprising EVOH and a molded product obtained from the resin composition comprising EVOH of the present invention and a film or sheet of another base material with an organic titanium compound, an isocyanate compound or a polyester-based resin. Examples include a method of laminating using a known adhesive such as a compound, and among others, a method of co-extrusion with another thermoplastic resin is preferably used.

The thermoplastic resin used includes linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, polypropylene, and propylene-α. -Olefin copolymer (carbon number 4
Α-olefins), polybutene, polypentene and other olefins alone or copolymers thereof, polyesters such as polyethylene terephthalate, polyester elastomers, polyamide resins such as nylon-6, nylon-6,6, polystyrene, polyvinyl chloride , Polyvinylidene chloride, acrylic resin, vinyl ester resin, polyurethane elastomer, polycarbonate, chlorinated polyethylene, chlorinated polypropylene and the like.
Among them, polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyamide, polystyrene, and polyester are preferably used.

When laminating the resin composition of the present invention with a thermoplastic resin, an adhesive resin may be used, and in this case, an adhesive resin composed of a carboxylic acid-modified polyolefin is preferable. Here, the carboxylic acid-modified polyolefin is a modified olefin-based polyolefin containing a carboxyl group obtained by chemically (eg, by addition reaction or graft reaction) bonding an ethylenically unsaturated carboxylic acid or its anhydride to an olefin polymer. Refers to merging. The term "olefin polymer" as used herein means polyethylene (low pressure, medium pressure, high pressure), linear low density polyethylene, polyolefin such as polypropylene, boribene, and comonomers (vinyl ester, non-polyester) capable of copolymerizing olefin with the olefin. (E.g., a saturated carboxylic acid ester), such as an ethylene-vinyl acetate copolymer and an ethylene-ethyl acrylate copolymer. Among them, linear low-density polyethylene, ethylene-vinyl acetate copolymer (vinyl acetate content 5 to 5)
55% by weight), ethylene-ethyl acrylate copolymer (content of ethyl acrylate 8 to 35% by weight) is preferred, and linear low-density polyethylene and ethylene-vinyl acetate copolymer are particularly preferred. It is. Ethylenically unsaturated carboxylic acids or anhydrides include ethylenically unsaturated monocarboxylic acids, esters thereof, ethylenically unsaturated dicarboxylic acids, mono or diesters thereof, and anhydrides thereof, and among them, ethylenically unsaturated dicarboxylic acids Anhydrides are preferred. Specific examples include maleic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride, monomethyl maleate, monoethyl maleate, diethyl maleate, monomethyl fumarate, among others, maleic anhydride Acids are preferred.

The amount of addition or grafting (degree of modification) of the ethylenically unsaturated carboxylic acid or anhydride thereof to the olefin polymer is 0.0001 to 0.0001 or less relative to the olefin polymer.
It is 15% by weight, preferably 0.001 to 10% by weight. The addition reaction and graft reaction of the ethylenically unsaturated carboxylic acid or its anhydride to the olefin polymer can be obtained by, for example, a radical polymerization method in the presence of a solvent (such as xylene) and a catalyst (such as peroxide). 190 ° C. of the carboxylic acid-modified polyolefin thus obtained
The melt flow rate (MFR) measured at 0.2 to 3
It is preferably 0 g / 10 min, more preferably 0.5 to 10 g / 10 min. These adhesive resins may be used alone or as a mixture of two or more layers.

The method of co-extrusion of the composition of the present invention with a thermoplastic resin is not particularly limited, and may be any of a multi-manifold merging T-die method, a feedblock merging T-die method, and an inflation method.

By subjecting the co-extruded multilayer structure thus obtained to secondary processing, various molded products (films, sheets, tubes, bottles, etc.) can be obtained. Can be (1) Multi-layer co-stretched sheet or film by uniaxially or biaxially stretching or biaxially stretching or heat-treating a multi-layered structure (sheet or film) (2) Multi-layered structure (sheet or film) (3) Multi-layered structure (sheet or film, etc.) Multi-layer tray cup-shaped container formed by vacuum forming, air-pressure forming, vacuum-pressure forming, etc. (4) Multi-layered structure Bottles and cup-shaped containers obtained by stretch blow molding from pipes (such as pipes). Such secondary processing methods are not particularly limited, and known secondary processing methods (such as blow molding) other than those described above can also be employed.

The multilayer structure thus obtained is excellent in low odor, has little fish eyes, is transparent, and has few streaks. Therefore, the material for food containers, for example, deep drawn containers, cup-shaped containers, bottles, etc. It is suitably used as a material.

[0072]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Hereinafter, “%” and “parts” are based on weight unless otherwise specified. In addition, all the water used ion-exchange water.

(1) Determination of content of carboxylic acid (A) 20 g of dry pellets as a sample were put in 100 m of deionized water.
and extracted by heating at 95 ° C. for 6 hours. The extract was prepared by using phenolphthalein as an indicator and using 1/50 N
The content of the carboxylic acid (A) was determined by neutralization titration with aOH.

(2) Determination of the ratio of the content (μmol / g) of the carboxylic acid (a1) having a molecular weight of 75 or more to the total content (μmol / g) of the carboxylic acid (A) and its salt (μmol / g) 20 g of dry pellets to be ion-exchanged in 100 m
and extracted by heating at 95 ° C. for 6 hours. Using the extract, a column SCS5-252 manufactured by Yokogawa Electric Corporation was applied to the column.
Was used, and each carboxyl anion was quantified by ion chromatography using a 0.1% phosphoric acid aqueous solution as an eluent, and the content of each acid and its salt was determined.

(3) Determination of alkali metal salt (B) and alkaline earth metal salt (C) (Na ion, K ion, M
(Quantitative determination of g ion and Ca ion) 10 g of a dry pellet 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 ion, K ion, Mg ion and Ca ion were quantified. The column is made of Yokogawa Electric's I
The eluent was an aqueous solution containing 5.0 mM tartaric acid and 1.0 mM 2,6-pyridinedicarboxylic acid using CS-C25. In the determination, a calibration curve prepared with an aqueous solution of sodium chloride, an aqueous solution of potassium chloride, an aqueous solution of magnesium chloride, and an aqueous solution of calcium chloride was used. From the amounts of the Na ion, K ion, Mg ion and Ca ion thus obtained, the amounts of the alkali metal salt (B) and the alkaline earth metal salt (C) in the dried pellet were obtained in terms of the metal element. .

(4) Quantification of Phosphate Compound (D) (Quantification of Phosphate Ions) 10 g of a dry pellet 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. Column, Inc.
Use ICS-A23 manufactured by Yokogawa Electric Corp.
An aqueous solution containing mM mM sodium carbonate and 1.0 mM sodium hydrogen carbonate was used. In the determination, a calibration curve prepared with an aqueous solution of sodium dihydrogen phosphate was used. From the amount of phosphate ions thus obtained, the content of the phosphate compound (D) was obtained in terms of phosphate groups.

(5) Determination of Boron Compound (E) 100 g of a dry pellet as a sample was put in a magnetic crucible,
Ashed in an electric furnace. The obtained ash was dissolved in 200 mL of a 0.01 N aqueous nitric acid solution and quantified by atomic absorption spectrometry, and the content of the boron compound (E) was obtained in terms of the amount of boron element.

(6) Relationship Between Heating Time and MFR 3 to 4 g of dried pellets as a sample were placed in a nitrogen atmosphere in a stainless steel pipe (2.2 cm in inner diameter, 12.5 cm in length,
Placed in the internal volume 50 cm ^3), after the inside of the stainless steel pipe was thoroughly replaced by nitrogen gas, it was carried out heat treatment at 220 ° C.. After the heat treatment, the MFR of the resin was measured using a melt indexer @ Melt Indexer L manufactured by Takara Kogyo Co., Ltd.
203 (pore diameter of cylinder to put sample: 9.48m
m, piston diameter φ9.48mm, die diameter φ2.09
mm, die length 8.01 mm)
After heating at 6 ° C. for 6 minutes, a load was applied at 10.9 kg and measurement was performed.

(7) Heat Melt Coloring Test 8 g of the dried pellets to be used as samples were sandwiched between hot plates heated at 230 ° C. (Sindoh tabletop test press YS-5), and the gap between the hot plates was maintained at 5 mm. After heating for one minute, the degree of coloring was visually determined and determined as follows. A: No coloring B: Slightly yellowing C: Yellowing D: Intense coloring

(8) Single-Layer Film-Forming Test A single-layer film was prepared by the following method, and the appearance, die adhesion amount, and long-run property of the molded product were evaluated. Model Single screw extruder (non-vented type) L / D 20 Caliber 20mmφ Screw Single full flight type, Surface nitrided steel Screw rotation speed 40rpm Dice 300mm width Coat hanger die Lip gap 0.3mm Cylinder, die temperature setting C1 / C2 / C3 / Die = 195/230/230/2
20 (° C)

(8-a) Variation in the number of gel-like bumps and the frequency of occurrence of gel-like bumps The above-described film formation was carried out continuously for 8 days, and the film was sampled every hour to obtain gel-like bumps (confirmed with the naked eye). About 15
(0 μm or more) was counted and converted to around 1.0 m ² , and the average value of the number of gel-like bumps per day was obtained from the obtained data. In addition, during the film forming test, the condition of streaks and gel-like spots is continuously visually observed, and the number of times per day that streaks and gel-like spots increase suddenly (100 pieces / m ² or more) is measured. did. (8-b) Amount of Die Attached After a single-layer film formation of EVOH was performed for 8 hours using the sample resin composition, the EVOH resin in the extruder was replaced with LDPE (low density polyethylene) with MFR = 1 for 1 hour. Thereafter, the weight of the EVOH thermally degraded resin attached inside the die was measured. It was determined as follows based on the weight. A: less than 1.5 g B: 1.5 to 5 g C: 5 to 10 g
D: 10g or more

(9) Interlaminar Adhesion T-peel strength between the ethylene-vinyl alcohol copolymer / adhesive resin immediately after the formation of the three-layer, five-layer film obtained by the following coextrusion molding was measured at 20 ° C.-65. % RH conditions,
The measurement was performed using an autograph (tensile speed: 250 mm / min). The value was determined as follows based on the peel strength. A: 500 g / 15 mm or more B: 300 to 500 g /
Less than 15 mm C; less than 300 g / 15 mm (co-extrusion molding conditions) Layer composition: LLDPE / adhesive resin / EVOH resin composition / adhesive resin / LLDPE (thickness 50/10/10/1)
0/50: unit is μm) LLDPE: ULTOZEX 3523L manufactured by Mitsui Chemicals Adhesive resin: Bondyne TX803 manufactured by Sumitomo Chemical Industries
0 Extrusion temperature of each resin: C1 / C2 / C3 / die = 170 /
170/220/220 ° C Extruder for each resin, T-die specification: LLDPE; 32φ extruder GT-32-A type (manufactured by Plastic Engineering Laboratory) Adhesive resin; 25φ extruder P25-18AC (manufactured by Osaka Seiki) EVOH ; 20φ extruder Laboratory machine ME type CO-EXT
(Made by Toyo Seiki Co., Ltd.) T-die; for 300mm width 3 types 5 layers (made by Plastics Engineering Laboratory) Cooling roll temperature: 50 ° C Picking speed: 4m / min

(10) Recoverability The formed EVOH single-layer film (film-formed product up to 2 hours after the start of film formation) is pulverized, melted and pelletized again (pelletization temperature: 220 ° C.). Single-layer film formation was performed again using the pellets. (10-a) Coloring resistance The film was wound around a paper tube, and the degree of coloring of the end face of the film was determined with the naked eye and determined as follows. A: No coloring B: Slightly yellowing C: Yellowing D: Intense coloring (10-b) Bubbles occurrence Gel-like bumps of the film 1 hour after performing single-layer film formation (approximately 150 μm or more that can be visually confirmed) ) And 1.
It was converted to around 0 m ² . Judgment was made as follows based on the number of spots. A: less than 20 B: 20 to 40 C: 40 to 60 D: 60 or more

(11) Odor A 20 g sample pellet of a resin composition comprising EVOH
It was placed in a 00 ml glass sample tube, the mouth was covered with aluminum foil, and then heated at 150 ° C. for 90 minutes in a hot air dryer. Take out from the dryer and let cool for 1 hour at room temperature.
After shaking the sample tube two or three times, the lid of the aluminum foil was removed and the odor was evaluated. The odor intensity of the sample pellet was determined based on the following criteria. A: no smell B: weak smell C: smell clearly felt D: quite strong smell

(12) Intrinsic Viscosity 0.20 g of a sample pellet of a resin composition composed of EVOH
Is weighed accurately, and this is hydrated phenol (water / phenol = 1).
(5/85 wt%), heated and dissolved in 40 ml at 60 ° C. for 3 to 4 hours, and measured at 30 ° C. with an Ostwald viscometer (t0 = 90 seconds). ]. [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 when blank (hydrous phenol) passes through viscometer ・ t: sample Time when the aqueous phenol solution in which is dissolved is passed through the viscometer

Example 1 A 45% methanol solution of an ethylene-vinyl acetate copolymer having an ethylene content of 38 mol% was charged into a saponification reactor.
Caustic soda / methanol solution (80 g / L) was added so as to be 0.4 equivalent to the vinyl acetate component in the copolymer, and methanol was added to adjust the copolymer concentration to 20%. . The temperature was raised to 60 ° C., and the reaction was carried out for about 4 hours while blowing nitrogen gas into the reactor. Four hours later, the reaction was stopped by neutralization with acetic acid, and the mixture was extruded into water from a metal plate having a circular opening to be precipitated, and cut to a diameter of about 3 mm.
A pellet having a length of about 5 mm was obtained. The operation of removing the obtained pellet by a centrifugal separator, adding a large amount of water, and removing the liquid was repeated.

100 parts by weight of water-containing pellets (ethylene content 38 mol%, saponification degree 99.4%, water content 55% by weight) of the thus obtained ethylene-vinyl alcohol copolymer were mixed with 0.8 g of sodium lactate / L, magnesium lactate 0.31 g / L, potassium dihydrogen phosphate 0.17 g /
L, lactic acid 0.08 g / L, and boric acid 0.32 g / L in 370 parts by weight of an aqueous solution at 25 ° C. for 6 hours. After immersion, the solution is drained, and then at 80 ° C. for 3 hours, and then at 107 ° C. for 2 hours.
Drying was performed using a hot air drier for 4 hours to obtain dried pellets. To 100 parts by weight of the dried pellets, 0.02 parts by weight of a lubricant Alflow H-50T (manufactured by NOF CORPORATION; ethylenebisstearic acid amide) was dry-blended and mixed well to obtain EVOH resin composition pellets.

The content of the carboxylic acid (A) in the obtained dried pellets was 0.90 μmol / g, and the total content of the carboxylic acid (A) and its salt was 10.3 μmol / g.
(The content of the carboxylic acid (a1) having a molecular weight of 75 or more and the salt thereof is 10.3 μmol / g.) The content of the alkali metal salt (B) is 220 ppm in terms of a metal element, and the content of the alkaline earth metal salt (C) is Content is 35 pp in metal element conversion
m, the content of the phosphoric acid compound (D) is 10
0 ppm and the content of the boron compound (E) were 240 ppm in terms of boron element. The obtained EVOH resin composition pellets had an MFR (measured at 190 ° C. under a load of 2160 g) of 2.0 g / 10 min and an intrinsic viscosity of 0.0 g / min.
It was 85 l / g.

Using the obtained EVOH resin composition pellets, the relationship between the heating time and the MFR was examined in accordance with the above-mentioned method (see FIG. 1), and a heat fusion coloring test was performed. MFRma
x / MFRO was 1.8, and the result of the heat-melt coloring test was A. In addition, the above-mentioned resin composition showed a minimum value within 10 hours from the start of heating, and a maximum value (MFRmax) within 100 hours after the minimum value was shown.

Using the obtained EVOH resin composition pellets, a single-layer film-forming test was conducted in accordance with the above-mentioned method, and the number of gel-like spots, the variation in the frequency of gel-like spots, and the amount of die attached were examined. The occurrence of gel-like spots was as low as 6 to 7 pieces / m ^{2 on} average for 8 days, no sudden increase in streaks or gel-like spots was observed, and a molded article with good appearance was obtained. It showed a long run. Further, the test result of the die adhesion amount was also judged as A.

Using the obtained EVOH resin composition pellets, the interlayer adhesion was measured by the method described above. The T-type peel strength between the resin composition / adhesive resin composed of EVOH immediately after film formation was determined to be A.

Using the film obtained in the single-layer film-forming test (film-formed product up to 2 hours after the start of film-forming), recoverability ((a) coloring resistance and (b) spot generation) by the above method. Was tested. In the test results, the recoverability was determined to be A in any of the evaluation items of (a) the color resistance and (b) the occurrence of spots.

Using the obtained EVOH resin composition pellets, an odor test was conducted by the method described above. The odor was evaluated as A.

Examples 2 to 6 and Comparative Examples 1 to 5 Using EVOH having an intrinsic viscosity shown in Table 2, an ethylene content of 38 mol% after saponification, washing and dewatering, and a saponification degree of 99.4% Dry pellets were prepared in the same manner as in Example 1 except that the composition of the solution for immersing the pellets made of EVOH was changed as shown in Table 1, and a lubricant was added. Table 2 shows the composition of the pellets used in each of Examples and Comparative Examples.
Table 3 summarizes the evaluation results of the various tests.

The resin compositions of Examples 2 to 6, Comparative Examples 1 to 3, and Comparative Example 5 exhibited a minimum value within 10 hours from the start of heating and a maximum value within 100 hours after the minimum value was exhibited. The value (MFRmax) was shown. However, in the resin composition of Comparative Example 4, the MFR did not show a minimum value or a maximum value.

[0096]

[Table 1]

[0097]

[Table 2]

[0098]

[Table 3]

EV of Examples 1 to 6 Having the Configuration of the Present Invention
The resin composition composed of OH is excellent in appearance with little coloring, fish eyes (gels / buds), streaks, etc., excellent in long-run property in melt molding, less coloring in collection, and in the laminate. When it did, it was excellent in interlayer adhesiveness. In Example 6, which did not contain a lubricant, the coloring resistance at the time of recovery, the effect of improving the generation of gel / bubbles, and the effect of reducing the amount of die attached were slightly reduced as compared with Example 1; Although the suppression effect and the effect of suppressing the sudden increase frequency of the number of gel-like bumps were somewhat reduced, they were practical.

However, in Comparative Example 1 in which the content of the carboxylic acid (A) in the resin composition was more than 4 μmol / g, sufficient adhesiveness could not be obtained, and conversely, the content of the carboxylic acid (A) was 0.1%. In Comparative Example 2 less than 05 μmol / g, the coloring resistance was unsatisfactory, and the effect of suppressing the generation of gel and butter was not sufficiently obtained.

Further, acetic acid is used as the carboxylic acid (A), and the total content of the carboxylic acid (A) and its salt (μmol
Comparative Example 3, in which the ratio of the content (μmol / g) of the carboxylic acid (a1) having a molecular weight of 75 or more and the salt thereof (μmol / g) to 0 / g) was 0, the odor improving effect was unsatisfactory.

Further, the resin composition was heated at 220 ° C. in a nitrogen atmosphere.
Time and MFR at 230 ° C (10.9kg load)
In Comparative Example 4, which does not have the configuration of the present invention in which the MFR shows a local minimum value within 10 hours from the start of heating, and shows a local maximum value (MFRmax) within 100 hours after showing the local minimum value, The effect of reducing the amount of die attached was not obtained, and the frequency of occurrence of gels and butters increased rapidly several times a day, resulting in poor productivity.

In Comparative Example 5 of the present application having the same configuration as that of Example 1 of the above-mentioned JP-A-10-67898,
Since MFRmax / MFR0 was more than 45, the color resistance was poor and the adhesion was insufficient, and the generation of gels and butters increased as the operation was continued for a long time.

[0104]

EFFECT OF THE INVENTION Coloring, fish eye (gel / buts),
Ethylene-vinyl alcohol copolymer with less streak, excellent appearance, excellent long-run property during melt molding, less coloring during recovery, excellent low odor, and excellent interlayer adhesion when used as a laminate It is possible to provide a resin composition comprising a union and a multilayer structure using the same.

[Brief description of the drawings]

FIG. 1 shows the heating time of a resin composition composed of EVOH at 220 ° C. in a nitrogen atmosphere and the MFR (230 ° C., 10.9 k
FIG. 4 is a diagram showing a relationship of (g load).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/09 C08K 5/09 C08L 23/26 C08L 23/26

Claims (11)

[Claims] 1. A resin composition comprising an ethylene-vinyl alcohol copolymer, wherein the MFR of the resin composition is increased when the resin composition is heated at 220 ° C. under a nitrogen atmosphere.
(230 ° C., 10.9 kg load) shows a local minimum value within 10 hours from the start of heating, and shows a local maximum value (MFRmax) within 100 hours after showing the local minimum value,
A resin composition containing a carboxylic acid (A) in an amount of 0.05 to 4 μmol / g and satisfying the following formulas (1) and (2). 0.5 ≦ MFRmax / MFR ≦ 45 (1) 0.1 ≦ (a1) / (A) ≦ 1.0 (2) where MFRmax: when the resin composition is heated at 220 ° C. under a nitrogen atmosphere. , MFR of the resin composition (230 ° C, 1
Maximum value MFR0 of 0.9 kg load): MFR (230 ° C., 10.9 kg) of the resin composition that has not been subjected to the heat treatment
(A): Total content of carboxylic acid (A) and its salt (μ)
mol / g) (a1): Content of carboxylic acid (a1) having a molecular weight of 75 or more and its salt (μmol / g) 2. The resin composition according to claim 1, which contains 50 to 500 ppm of the alkali metal salt (B) in terms of a metal element. 3. An alkaline earth metal salt (C) containing 10 to 120 ppm in terms of a metal element.
3. The resin composition according to item 1. 4. The phosphoric acid compound (D) is converted to a phosphate group by 1
The resin composition according to any one of claims 1 to 3, which contains 0 to 500 ppm. 5. The resin composition according to claim 1, wherein the boron compound (E) is contained in an amount of 50 to 2,000 ppm in terms of boron element. 6. The resin composition according to claim 1, wherein the carboxylic acid (a1) having a molecular weight of 75 or more is a hydroxycarboxylic acid. 7. The resin composition according to claim 1, wherein the carboxylic acid (a1) having a molecular weight of 75 or more is lactic acid. 8. The resin composition according to claim 1, wherein the following formula (3) is satisfied. 2 ≦ [B (μmol / g) + C (μmol / g)] / [A (μmol / g) + D (μmol / g)] ≦ 9 (3) where A: carboxylic acid per unit weight of the resin composition Content of (A) (μmol / g) B: Content of alkali metal salt (B) per unit weight of resin composition (in terms of metal element: μmol / g) C: Alkali per unit weight of resin composition Content of earth metal salt (C) (in terms of metal element: μmol / g) D: Phosphoric acid compound (D) per unit weight of resin composition
Content (in terms of phosphate radical: μmol / g) 9. An ethylene-vinyl alcohol copolymer 1
The resin composition according to any one of claims 1 to 8, comprising 0.005 to 1 part by weight of a lubricant based on 00 parts by weight. 10. A resin composition 100 on the outer surface of a pellet comprising the resin composition according to claim 1.
A resin composition pellet comprising 0.005 to 0.5 parts by weight of a lubricant adhered to parts by weight. 11. A multilayer structure comprising a layer made of the resin composition according to claim 1 and a thermoplastic resin laminated on at least one surface of the layer.