JP3169279B2 - Inner container for bag-in-box - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner container for a bag-in-box, and more particularly, to an inner container for a bag-in-box which is excellent in punching workability of a liquid inlet and maintains gas barrier properties for a long period of time. Is provided.

[0002]

2. Description of the Related Art In general, saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH) is excellent in transparency, antistatic property, oil resistance, solvent resistance, gas barrier property, fragrance retention property and the like. However, it is a material having disadvantages such as low impact resistance, bending fatigue resistance, stretchability, thermoformability, and low gas barrier properties when absorbing moisture or water. For this reason, in the intended use of packaging materials, a gas barrier property, aroma retention property, and food discoloration prevention property are obtained by laminating films of low density polyethylene, polypropylene, nylon, polyester, etc. on both sides of an EVOH film. While maintaining the characteristics of EVOH, such as falling strength, thermoformability, moisture proof, etc., it is used for various packaging applications by compensating for the disadvantages of EVOH.

[0003] In recent years, bag-in-box containers have been used as packaging containers for transporting and storing liquids for beverages such as wine and juice, and liquids for photographic developers. This bag-in-box is
A flexible plastic packaging container provided with a liquid injection port is housed inside a cardboard box, and is frequently used as a means for transporting various liquids. The above-described EVOH laminate is also used as an inner container of the bag-in-box. Has been reached.

The required performance of the inner container at this time is as follows:
Since it is important to maintain excellent gas barrier properties against extremely severe bending fatigue at the time of transportation and the like, various attempts have been made, and linear low-density polyethylene layers / adhesive layers / EVOH layers / Laminate of adhesive / linear low-density polyethylene (hereinafter abbreviated as LLDPE) layer (JP-A-60-161146), LLDPE layer / adhesive layer / EVOH layer / adhesive layer / ethylene-vinyl acetate Laminated body of copolymer resin layer, biaxially oriented nylon layer, or biaxially oriented polypropylene (Japanese Patent Laid-Open No. 60-168649), surface layer / carboxylic acid-modified LLDPE / EVOH
A laminate of a layer / a carboxylic acid-modified LLDPE / surface layer (JP-A-60-24205) has been proposed.

[0005]

However, the laminated film using EVOH as an intermediate layer as described above has a high gas barrier that can withstand long-term storage and transportation, although the bending fatigue resistance is improved. Sex is still inadequate. The reason for this is that in manufacturing the inner container, it is necessary to make a liquid injection port in the inner container, and a punched hole is made in the laminated film. At this time, the EVOH layer has little flexibility because the EVOH layer has little flexibility. Cracks are generated, and the cracks grow due to stress during transportation or the like, which ultimately results in impaired gas barrier properties.

[0006]

Means for Solving the Problems Accordingly, the present inventors have conducted intensive studies to solve the above problems, and as a result, (i) EVOH and (ii) terminal carboxyl group (-C
OOH) and the terminally substituted amide group (—CONR)
R ′) [where R is a hydrocarbon group having 1 to 22 carbon atoms, R ′
Is a hydrogen atom or a hydrocarbon group having 1 to 22 carbon atoms], and the ratio of the number (n) is [(n) / ((m) + (n))] × 10
A bag-in in which a mixture composition (A) with a polyamide resin satisfying 0 ≧ 5 is used as an intermediate layer, an adhesive layer is provided on both sides of the intermediate layer, and a surface layer is further provided outside the adhesive layer. The present inventor has found that the inner container for a box can maintain good gas barrier properties even during transportation for a long period of time without cracking during production of the liquid inlet, and completed the present invention. Hereinafter, the present invention will be described in detail.

[0007] The EVOH (i) used in the present invention has an ethylene content of 20 to 80 mol%, preferably 25 to 60 mol%.
Mol%, the degree of saponification of the vinyl acetate component is 90 mol% or more,
Preferably, one having 95 mol% or more is usually used. If the ethylene content is less than 20 mol%, the oxygen barrier property at high humidity decreases, while if it exceeds 80 mol%, physical properties such as oxygen barrier property deteriorate. On the other hand, if the saponification degree is less than 90 mol%, the oxygen barrier property and the moisture resistance are reduced. Among these EVOHs, the intrinsic viscosity (measured at 30 ° C. as a 15% aqueous phenol solution) is 0.7 to 1.5 dl / g, preferably 0.8 to 1.5 dl / g.
1.3 dl / g is suitably used in terms of the mechanical strength of the molded product.

The EVOH is a small amount of α-olefins such as propylene, isobutene, α-octene, α-dodecene and α-octadecene, and unsaturated carboxylic acids as long as the properties such as transparency and gas barrier properties are not impaired. Alternatively, a comonomer such as a salt thereof, a partial alkyl ester, a complete alkyl ester, a nitrile, an amide, an anhydride, an unsaturated sulfonic acid or a salt thereof may be contained. Furthermore,
The polyamide resin (ii) has a number (m) of terminal carboxyl groups (—COOH) and a terminal substituted amide group (—COOH).
NRR ′) [R represents a hydrocarbon group having 1 to 22 carbon atoms, R ′ represents a hydrogen atom or a hydrocarbon group having 1 to 22 carbon atoms] and the number (n) is [(n) / ( (M) + (n))] × 1
00 ≧ 5. That is, a lactam of three or more members,
A polyamide obtained by polymerization or copolymerization of an ε-amino acid or a dibasic acid with a diamine, or the like, in which the terminal carboxyl group is modified with an N-substituted amide. Usually, monosubstituted amide modification (R 'is a hydrogen atom) is practical,
Disubstituted amide modification may be used.

In order to produce the polyamide resin of the present invention, a polyamide raw material is polycondensed in the presence of the following or: Monoamine having 1 to 22 carbon atoms, monoamine having 1 to 22 carbon atoms and monocarboxylic acid having 2 to 23 carbon atoms Specific examples of the polyamide raw material include ε-caprolactam, enantholactam, caprylactam, lauryl lactam, α Lactams such as -pyrrolidone, α-piperidone, ω-amino acids such as 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, adipic acid, glutaric acid, pimelic acid, Spearic acid, azelaic acid, sebacic acid, undecandioic acid, dodecadionic acid, hexadecadionic acid, hexadecenedionic acid, eicosandioic acid, eicosadienedioic acid, diglycolic acid, 2,2,4-trimethyladipic acid, Xylylenedicarboxylic acid, 1,4
Dibasic acids such as cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, hexamethylenediamine,
Tetramethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,
2,4 (or 2,4,4) -trimethylhexamethylenediamine, bis- (4,4'-aminocyclohexyl)
Examples include diamines such as methane and meta-xylylenediamine.

The monoamine having 1 to 22 carbon atoms includes methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, 2-ethylhexylamine, nonylamine, decylamine, undecylamine and dodecylamine. Alicyclic monoamines such as aliphatic monoamines such as tridecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, octadecylamine, octadecyleneamine, eicosylamine and docosylamine, cyclohexylamine and methylcyclohexylamine Aromatic amines such as benzylamine, β-phenylethylamine, N, N-dimethylamine,
N, N-diethylamine, N, N-dipropylamine,
N, N-dibutylamine, N, N-dihexylamine,
Symmetric secondary amines such as N, N-dioctylamine, N, N-didecylamine, N-methyl-N-ethylamine, N-methyl-N-butylamine, N-methyl-N-
Dodecylamine, N-methyl-N-octadecylamine, N-ethyl-N-hexadecylamine, N-ethyl-N-octadecylamine, N-propyl-N-hexadecylamine, N-methyl-N-cyclohexylamine, Hybrid secondary amines such as N-methyl-N-benzylamine are exemplified.

The monocarboxylic acids having 2 to 23 carbon atoms include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, capric acid, pelargonic acid, undecanoic acid, lauric acid and tridecanoic acid. Alicyclic monocarboxylic acids such as aliphatic monocarboxylic acids such as acetic acid, myristic acid, myristoleic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, arachinic acid and pehenic acid; cyclohexanecarboxylic acid and methylcyclohexanecarboxylic acid Examples thereof include acids, benzoic acid, toluic acid, ethyl benzoic acid, and aromatic monocarboxylic acids such as phenylacetic acid.

If necessary, ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine may be used in addition to the above-mentioned monoamine or monoamine and monocarboxylic acid. , Decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecamethylenediamine, hexadecamethylenediamine, octadecadimethylenediamine, 2,2,4 (or 2,4,4) -trimethylhexamethylenediamine Aliphatic diamines, alicyclic diamines such as cyclohexanediamine, methylcyclohexanediamine, bis- (4,4'-aminocyclohexyl) methane, and aromatic diamines such as xylylenediamine Diamines such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, undecandioic acid,
Dodecandionic acid, tridecadionic acid, tetradecadionic acid, hexadecadionic acid, hexadecenedionic acid, octadecadionic acid, octadescedionic acid, eicosandioic acid, eicosendioic acid, docosandioic acid,
Aliphatic dicarboxylic acids such as 2,2,4-trimethyladipic acid, alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid,
A dicarboxylic acid such as an aromatic dicarboxylic acid such as phthalic acid or xylylene dicarboxylic acid can be used together.

In the reaction for producing the polyamide resin of the present invention, the above-mentioned polyamide raw material may be used and the reaction may be started according to a conventional method. The carboxylic acid and amine are reacted from the start of the reaction until the start of the reaction under reduced pressure. It can be added at any stage. Further, the carboxylic acid and the amine may be added simultaneously or separately. The amount of the carboxylic acid and the amine used is 2 as the amount of the carboxyl group and the amino group, respectively, per 1 mol of the polyamide raw material (1 mol of the monomer constituting the repeating unit or 1 mol of the monomer unit).
20 to 20 meq / mol, preferably 3 to 19 meq / mol (the equivalent of amino group is 1: 1 with 1 equivalent of carboxylic acid.
The amount of the amino group that forms an amide bond by the reaction is 1 equivalent). If the amount is too small, it becomes impossible to produce a polyamide resin having the effects of the present invention. Conversely, if the amount is too large, it becomes difficult to produce a polyamide having a high viscosity, which adversely affects the physical properties of the polyamide resin.

The reaction pressure is 400 Torr at the end of the reaction.
The heat treatment is preferably performed at a temperature of 300 Torr or less. If the pressure at the end of the reaction is high, the desired relative viscosity cannot be obtained. There is no disadvantage at low pressures. The reaction under reduced pressure is preferably performed for 0.5 hour or more, usually for 1 to 2 hours. R or R ′ in the substituted amide group (—CONRR ′) at the terminal of the polyamide resin of the present invention.
Examples of the hydrocarbon group represented by are a methyl group, an ethyl group,
Propyl, butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, tetradecylene, pentadecyl, hexadecyl, Aliphatic hydrocarbon groups such as heptadecyl group, octadecyl group, octadecylene group, eicosyl group, docosyl group, alicyclic hydrocarbon groups such as cyclohexyl group, methylcyclohexyl group and cyclohexylmethyl group, phenyl group, toluyl group, benzyl Group, β
And an aromatic hydrocarbon group such as -phenylethyl group.

The terminal of the COOH group of the polyamide resin
The conversion ratio to the CONRR ′ group is adjusted by the presence of an amine or an amine and a carboxylic acid during the production of the polyamide resin. In the present invention, the degree of this conversion is at least 5 mol% of the —COOH group. , Preferably 10
Preferably, at least mol% is converted to -CONRR 'groups, and the amount of unconverted -COOH groups is 5%.
0 μeq / g · polymer or less, preferably 40 μeq / g
g · polymer or less is desirable. If the degree of this conversion is small, the effect of the present invention cannot be expected. Conversely, increasing the degree of conversion is not inconvenient in terms of physical properties, but makes production difficult, so it is advisable to limit the amount of unmodified terminal carboxyl groups to 1 μeq / g · polymer. .

The hydrocarbon group represented by R and R 'of the -CONRR' group is measured by gas chromatography after hydrolyzing a polyamide resin with hydrochloric acid. −
The COOH group is measured by dissolving the polyamide resin in benzyl alcohol and titrating with 0.1N sodium hydroxide. As the terminal group of the polyamide resin, the above-mentioned -CONRR '
-COO derived from the above-mentioned polyamide raw material
It is H groups and -NH ₂ groups. For the terminal amino group,
It may be modified or unmodified, but is preferably modified with the above-mentioned hydrocarbons because of its good fluidity and melt heat stability. —NH ₂ group is obtained by dissolving a polyamide resin in phenol,
Measure by titration with N hydrochloric acid. The relative viscosity [ηrel] of the polyamide resin of the present invention is 2 to 6, preferably 2 to 5 as measured at a concentration of 98% sulfuric acid of 1% and a temperature of 25 ° C. according to JIS K 6810. If the relative viscosity is too low, it becomes difficult to form strands and chips, which is inconvenient in production. Conversely, if it is too high, the moldability will deteriorate.

In the present invention, the mixing ratio of (i) and (ii) is selected from (i) / (ii) = 98/2 to 2/98, preferably 95/5 to 10/90 on a weight basis. (I) / (i
When i) is 98/2 or more, the effect of improving the impact resistance of EVOH cannot be obtained. Conversely, when the value is 2/98 or less, the effect of improving the oxygen barrier property and rigidity of the polyamide resin is low, resulting in poor practicality. poor. In addition, as the resin component of the intermediate layer of the present invention, in addition to the above (i) and (ii), a plasticizer (such as a polyhydric alcohol), a stabilizer, a surfactant, a crosslinkable substance (an epoxy compound, a polyvalent metal). Salts, inorganic or organic polybasic acids or their salts, etc.), fillers, coloring agents, fibers (glass fibers, carbon fibers, etc.) as reinforcing agents, etc. can be added in appropriate amounts.

Further, other thermoplastic resins may be blended in an appropriate amount. Examples of such thermoplastic resins include polyolefins (low / medium / high density polyethylene, isotactic polypropylene, ethylene-propylene copolymer, ethylene-propylene copolymer). A diene copolymer, ethylene and carbon number 4
The above copolymers with α-olefins, ethylene-vinyl acetate copolymers or saponified products thereof, ethylene-acrylate copolymers, ionomers, polybutenes, polypentenes, etc.) or these with unsaturated carboxylic acids or derivatives thereof Graft-modified modified polyolefins, polyamides such as nylon 6/66 copolymer, polyvinyl chloride, polyvinylidene chloride, polyester, polystyrene, polyacrylonitrile, polyacetal, and melt-moldable polyvinyl alcohol-based resins.

The inner container for a bag-in-box according to the present invention comprises:
It comprises at least a five-layer laminate of a surface layer / adhesive layer / intermediate layer (A) / adhesive layer / surface layer, and the surface layer has a density of 0.86 to 0.95 g / cm ³ (20 ° C.) The ethylene-α-olefin copolymer is preferred. The density here is a value measured according to JIS K 6760 at 20 ° C. When the density is smaller than the above range,
The mechanical properties of the laminate are insufficient, and blocking tends to occur. On the other hand, when it is large, the bending fatigue resistance of the bag as a bag-in-box becomes insufficient, which is not preferable. In addition, ethylene-α-olefin refers to ethylene and butene-1, pentene-1,4-methylpentene-
It is a copolymer having 18 or less carbon atoms such as 1, hexene-1, octene-1, and the like. Among them, α- having 4 to 8 carbon atoms.
An ethylene-α-olefin copolymer using an olefin is preferably used.

Further, as the adhesive resin used for the adhesive layer, a density modified with an unsaturated carboxylic acid or an anhydride thereof is 0.86 to 0.95 g / cm ³ (measurement conditions are as follows. Ethylene-α-olefin copolymer) is preferable, and can be obtained by copolymerizing or graft-modifying the same resin as described in the above surface layer with an unsaturated carboxylic acid or an anhydride thereof. Of course, the modification includes a blend of an unmodified ethylene-α-olefin copolymer and an unsaturated carboxylic acid or an anhydride thereof. As unsaturated carboxylic acids or anhydrides thereof, maleic acid,
Maleic anhydride, fumaric acid, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, citraconic acid, hexahydrophthalic anhydride and the like can be mentioned, and among them, maleic anhydride is preferably used.

At this time, the amount of the unsaturated carboxylic acid or anhydride contained in the ethylene-α-olefin copolymer is preferably from 0.01 to 10% by weight, more preferably from 0.1 to 3% by weight. It is. If the content in the modified product is small, the adhesive strength between the intermediate layer and the surface layer is reduced. If the content is large, a crosslinking reaction is caused, and the moldability is deteriorated.
The thickness of each layer of the laminate of the surface layer / adhesive layer / intermediate layer (A) / adhesive layer / surface layer of the present invention is 10 to 10 respectively.
600μ / 2-50μ / 1-100μ / 2-50μ / 1
0 to 600 μm, preferably 30 to
200 μ / 5 to 10 μ / 5 to 30 μ / 5 to 10 μ / 30
~ 200μ.

The greatest feature of the present invention resides in that EVOH containing a specific polyamide resin is used for the intermediate layer. The laminate of the present invention using the EVOH for the intermediate layer has a surface layer / adhesive layer / Intermediate layer (A) / Adhesive layer / Surface layer in which a layer is further provided outside the surface layer, not limited to the structure of the surface layer / Adhesive layer / Intermediate layer (A) / Adhesive layer / Surface layer / Adhesive layer / surface layer, surface layer / adhesive layer / surface layer / adhesive layer / intermediate layer (A) / adhesive layer / surface layer / adhesive layer / surface layer It is also possible. Furthermore,
Surface layer / adhesive layer / nylon layer /
Intermediate layer (A) / adhesive layer / surface layer, surface layer / adhesive layer /
Nylon layer / intermediate layer (A) / nylon layer / adhesive layer / surface layer, surface layer / adhesive layer / nylon layer / adhesive layer / intermediate layer (A) / adhesive layer / surface layer It is also possible to use nylon 6, nylon 6-66, nylon 1
2, amorphous nylon, or blends thereof.

The adhesive layer and the surface layer of the laminate of the present invention may further include an antioxidant for improving moldability and physical properties.
A slip agent, hydrotalcites, an antistatic agent, a plasticizer, a colorant, and the like can be added as long as the effects of the present invention are not impaired. The inner container for a bag-in-box of the present invention can be manufactured mainly by a heat sealing method and a blow molding method. In the heat sealing method, a laminated body obtained by dry laminating a film for an intermediate layer and a film for a surface layer formed by an inflation method or an extruding method via an adhesive layer or a laminated body obtained by laminating each layer by a coextrusion method or the like. As it is, or as a double or triple overlap as necessary, a hole for sealing the liquid inlet is punched out, and a sealing plug for the liquid inlet previously molded by injection molding is melted into the hole by a heat sealing method. To wear. At this time, the laminated body and another laminated body which has not been subjected to the punching process are combined and heat-sealed in four directions to obtain a bag-in-box or other inner container. In the blow molding method, the cylindrical laminated body extruded from an extruder is molded by clamping with a die. The sealing stopper of the liquid inlet is previously molded by injection molding and set in a mold, and is fused to a molding container during blow molding. Thereafter, the liquid inlet is opened.

[0024]

The inner container for a bag-in-box according to the present invention uses an EVOH layer containing a specific polyamide resin in the intermediate layer, so that no cracks are generated in the punching step at the time of manufacturing the inner container. An inner container for a bag-in-box having excellent long-term gas barrier properties can be obtained.

[0025]

The present invention will be specifically described below with reference to examples. In the examples, “parts” and “%” mean on a weight basis unless otherwise specified. Production of polyamide resin (N-1 to 4) Four kinds of polyamide resins were produced by the following method.
In a 200 l autoclave, ε-caprolactam 60
kg, 1.2 kg of water, and the amount of monoamine and carboxylic acid shown in Table 1 below were charged, sealed in a nitrogen atmosphere, heated to 250 ° C., and reacted under pressure for 2 hours with stirring. Gradually release the pressure and reduce it to the pressure shown in Table 1 below,
The reaction was performed under reduced pressure for 2 hours. After the pressure was restored to normal pressure by introducing nitrogen, the stirring was stopped and the strand was drawn out as a strand to form a chip. The unreacted monomer was extracted and removed using boiling water, followed by drying. Relative viscosity of the obtained polyamide resin, terminal -COO
H group amount, ratio of the number of terminal -NH ₂ groups and terminal -COOH groups (m) to the number of terminal -CONRR 'groups (n) [[(n) / ((m) + (n))] × 100, mol%]
Are shown in Table 2.

[0026]

Table 1 N-1 N-2 N-3 N-4 Types of monoamines Octatedecylamine Octatedecylamine Amount of octatedecylamine- 〃 (meq / mol) 3.39 5.30 0.45 Type of carboxylic acid Stearic acid Acetic acid Stearic acid Amount of acetic acid salt (meq / mol) 3.39 5.30 0.45 4.76 Final pressure of polymerization reaction (Torr) 200 270 330 690

[0027]

[Table 2] N-1 N-2 N-3 N-4 terminal carboxyl group 20 26 3084 (μeq / g · polymer) terminal amino group 21 25 31 42 (μeq / g · polymer) [(n) / ( (m) + (n))] × 100 60 64 100 (mol%) Relative viscosity 2.89 2.22 3.61 2.49 (ηrel)

EVOH (E-1 to 3) As shown in Table 3, three types of EVOH were prepared.

TABLE 3 E-1 E-2 E- 3 Ethylene content 36 28 43 (mol%) Ke emission degree 99.3 98.6 99.5 (mol%) pole limit viscosity 0.78 0.78 0.90 (dl / g)

Example 1 Using a three-type five-layer co-extrusion apparatus, the intermediate layer was formed of EVOH (E
-1) 90 parts, a layer (A-1) of a resin composition containing 10 parts of a polyamide resin (N-1), and both outer layers each having an MI (melt index) of 2.5 g / 10 minutes (190 ° C., load 2
160 g), a density of 0.890 g / cm ³ , an ethylene-1-butene random copolymer LLDPE (B-1) having an ethylene content of 90 mol%, and an anhydride having an MI of 3.0 between the intermediate layer and both outer layers. LLDPE with 0.5% maleic acid content
(B-1) / (C-1) / (A-1) / (C-1) / comprising the adhesive resin layer (C-1) comprising (B-1).
(B-1) is 35μ / 10μ / 10μ / 10μ / 35μ
Was obtained under the following coextrusion molding conditions.

Co-extrusion molding conditions : Extruder (A): 30 mmф, screw; full flight type, L / D; 28 Temperature condition (° C.): supply section; 180, compression section; 200, measuring section; : 1.5 kg / hr Extruder (B): 30 mmф, screw; full flight type, L / D; 26 temperature condition (° C): supply section; 160, compression section; 200, measuring section; 220 discharge amount: 3 0.0 kg / hr Extruder (C): 40 mmф, screw; full flight type, L / D; 24 Temperature condition (° C.): supply part; 200, compression part; 210, measuring part; 210 discharge amount: 10.0 kg / Hr Feed block temperature: 220 ° C Die temperature: 220 ° C

The obtained laminated film (500 mm × 70
0 mm) were stacked, and a hole (diameter: 43 mm) for liquid injection was made by a punching machine. Next, a laminated film without holes (500 mm × 700 mm laminated) was superposed on the laminated film and heat-sealed on all sides to produce a bag-in-box inner container. At that time, a high-density polyethylene sealing stopper was attached to the hole for liquid injection and heat-sealed around and tightly fixed. Next, place the inner container in a cardboard box, and put water therein for about 18 hours.
A running transport test of about 2000 km in liters was conducted. After the test, the state of the laminated film around the sealing stopper of the inner container was visually observed with an SEM (electron microscope, 500 times). The oxygen permeation amount (cc / cc) of the inner container before and after the test
The air / bag / day) was examined under the conditions of 20 ° C. and 65% RH using an oxygen permeation meter (OX-TRAN 10/50) manufactured by Modern Control.

Examples 2 to 4 Using the intermediate layer, the adhesive layer and the surface layer shown in Table 4, an inner container was prepared and evaluated in the same manner as in Example 1. Comparative Examples 1 and 2 Using the intermediate layer, the adhesive layer, and the surface layer shown in Table 4, an inner container was prepared and evaluated in the same manner as in Example 1. Table 4 shows the evaluation results of the examples and the comparative examples.

[0033]

[Table 4] Lamination structure ¹⁾ Evaluation items Intermediate layer Surface layer Adhesive layer SEM observation Oxygen permeability ²⁾ Example 1 A-1 B-1 C-1 No abnormality 0.08 / 0.10 Example 2 A-2 B-2 C-2 No abnormality 0.15 / 0.15 Example 3 A-3 B-3 C-3 No abnormality 0.32 / 0.33 Example 4 A-4 B-4 C-1 No abnormality 4.20 / 4.22 Comparative Example 1 A-5 B-1 C-1 ** Comparative Example 2 A-6 B-2 C-2 Cracking ** 0.06 / 200 <

1) Each constituent resin is as follows. A-1; 90 parts of (E-1) and 10 parts of (N-1) are blended A-2; (E-2) 80 parts and 20 parts of (N-2) are blended A-3; (E-3) ) 60 parts and (N-3) 40 parts A-4; (E-3) 30 parts and (N-1) 70 parts A-5; (E-3) 80 parts and (N-4) ) 20 parts blended A-6; (E-1) only

B-1: MI 2.5 g / 10 min, density 0.
890 g / cm ³ , ethylene content of 90 mol% ethylene-1-butene random copolymer B-2; MI 4.0 g / 10 min, density 0.872 g / c
m ³ , ethylene-1-butene random copolymer having an ethylene content of 82 mol% B-3; MI 0.8 g / 10 min, density 0.864 g / c
m ³ , ethylene-propylene copolymer B-4 having an ethylene content of 80 mol%; MI 2.0 g / 10 min, density 0.920 g / c
m ³ , an ethylene-4-methylpentene-1 copolymer having an ethylene content of 97 mol% C-1; a product obtained by grafting 0.5% of maleic anhydride onto the above B-1. C-2: 90 parts of B-1 blended with 10 parts of the above B-2 grafted with 2.5% maleic anhydride. C-3: Maleic anhydride grafted to B-3 above at 3%. 2) Oxygen permeability is represented by values before and after the test. * During the production of the laminate, a large amount of gel was generated, and molding of the laminate was impossible. ** Leakage was observed around the liquid inlet.

[0036]

The inner container for a bag-in-box according to the present invention is an EVO having a specific polyester resin in the intermediate layer.
Since the H layer is used, a bag-in-box inner container having excellent gas barrier properties can be obtained without cracks in the punching process during the production of the inner container, and can be subjected to impacts such as long-time transportation. It can withstand and is extremely useful.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-161146 (JP, A) JP-A-60-168649 (JP, A) JP-A-60-242054 (JP, A) JP-A-3- 76644 (JP, A) JP-A-63-179935 (JP, A) JP-A-62-22840 (JP, A) JP-A-62-252446 (JP, A) JP-A-2-29450 (JP, A) JP-A-63-179740 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 B65D 77/00-77/40

Claims (4)

(57) [Claims] (1) a saponified ethylene-vinyl acetate copolymer, (ii) the number (m) of terminal carboxyl groups (—COOH) and a terminal substituted amide group (—CONRR ′) [where R is carbon A hydrocarbon group having 1 to 22 carbon atoms, R ′ is a hydrogen atom or a hydrocarbon group having 1 to 22 carbon atoms],
A mixture composition (A) with a polyamide resin satisfying [(n) / ((m) + (n))] × 100 ≧ 5 is used as an intermediate layer, and adhesive layers are provided on both sides of the intermediate layer. An inner container for a bag-in-box, further comprising a surface layer provided outside the adhesive layer. 2. The weight ratio of (i) and (ii) is (i) /
2. The inner container for a bag-in-box according to claim 1, wherein (ii) = 98/2 to 2/98. 3. The surface layer has a density of 0.86 to 0.95 g / c.
The inner container for a bag-in-box according to claim 1, comprising an ethylene-α-olefin copolymer having m ³ (20 ° C). 4. An adhesive layer modified with an unsaturated carboxylic acid or an anhydride thereof at a density of 0.86 to 0.95 g / cm.
^{3. The} inner container for a bag-in-box according to claim 1, comprising an ethylene-α-olefin copolymer of ³ (20 ° C.).