JP2008290771A - Manufacturing method of barrier vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of efficiently manufacturing a vessel showing excellence in jointing strength and a barrier property. <P>SOLUTION: The method of manufacturing the barrier vessel having a barrier layer on at least the inner surface by jointing vessel members to each other includes a step (1) of shaping a thermoplastic resin vessel member, the step (2) of applying a coat liquid containing a polymer component (A) containing a hydroxyl group and a carboxyl group, the ratio of the hydroxyl group to the carboxyl group being 30:70 to 95:5 (number ratio), and a liquid medium to at least the inner surface of each vessel member obtained in the step (1) of forming a film, the step (3) of jointing the vessel members each having the film on at least the inner surface to obtain a primary vessel, and a step (4) of drying and heating the primary vessel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a container having excellent barrier properties.

  Containers having excellent barrier properties are conventionally used for foods, beverages, medical containers and the like. In the automobile field, a barrier container made of a thermoplastic resin is often used as a fuel container because it is excellent in rust prevention, light weight, moldability, and design freedom. As such a resin-made barrier fuel container, a multilayer container in which a layer made of high-density polyethylene and a barrier layer made of an ethylene-vinyl alcohol copolymer are laminated is common. For example, Patent Document 1 discloses that in a multilayer container in which a high-density polyethylene layer / adhesive resin layer / ethylene-vinyl alcohol copolymer layer / adhesive resin layer / high-density polyethylene layer are laminated in this order, ethylene-vinyl alcohol copolymer A fuel container is described in which the coalesced layer (barrier layer) is closer to the inner layer of the container to improve gasoline barrier properties, particularly oxygen-containing gasoline barrier properties.

However, the fuel container as disclosed in Patent Document 1 has a problem in that the innermost layer of the fuel container is a high-density polyethylene layer, so that the high-density polyethylene layer is swollen by the fuel as the contents. This was an obstacle when recycling used fuel containers.
As a method for solving this problem, Patent Document 2 describes a fuel container in which a barrier material is further coated on the inner layer surface of a fuel container obtained by joining an upper bottom surface and a lower bottom surface made of a thermoformed multilayer sheet. As a manufacturing method thereof, after the multilayer sheet is thermoformed to obtain a thermoformed multilayer sheet, the surface of the multilayer sheet that becomes the innermost layer side when the ends of the two thermoformed multilayer sheets are joined together is And a method of heat-sealing the ends of the thermoformed multilayer sheet after coating with a layer made of a barrier material.

JP-A-9-29904 JP 2003-2071 A

Citation 2 describes that when the surface of a multilayer sheet is coated with a barrier material, the heat-sealed portion of the sheet must not be covered with the barrier material. This is because when the heat-sealed portion is covered with the barrier material, the adhesive strength of the joint portion is reduced when heat-sealing. On the other hand, from the viewpoint of barrier properties, it is desirable that the vicinity of the joint on the inner surface of the container is covered with a barrier layer.
As described above, since the heat seal portion is not covered with the barrier material and the inner surface is completely covered with the barrier material, the barrier material needs to be carefully covered.

  The present inventors have found that by using a specific barrier material, it becomes possible to join even if the part to be joined is covered with the barrier material, and a container excellent in joining strength and barrier property can be obtained efficiently. The present invention has been reached.

That is, the present invention is a method of manufacturing a barrier container having the following steps by joining container members to each other and having a barrier layer on at least an inner surface.
(1) Step of molding a container member made of a thermoplastic resin (2) At least the inner surface of each container member obtained in step (1) has a hydroxyl group and a carboxyl group, hydroxyl group: carboxyl group = 30: 70 to 95: A step of applying a coating liquid containing a polymer component (A) containing 5 (number ratio) and a liquid medium, and forming a film (3) joining container members formed with a film on at least the inner surface Step for obtaining primary container (4) Step for dry heat treatment of primary container

According to the present invention, since the joining is possible even if the part to be joined is covered with a barrier material, a container having excellent joining strength and excellent barrier properties can be produced efficiently.

Step (1) in the method for producing a barrier container having a barrier layer on at least the inner surface of the present invention is a step of molding a container member made of a thermoplastic resin. The thermoplastic resin is not particularly limited, and examples thereof include olefinic resins such as polyethylene, ethylene-α-olefin copolymer, polypropylene, and polyester resins. Two or more kinds of thermoplastic resins may be used. In addition, antioxidants, ultraviolet absorbers, light stabilizers, lubricants, anti-blocking agents, waxes, petroleum resins, antistatic agents, inorganic fillers as fillers (for example, “Plastic and Rubber Additives Handbook” (See, for example, 1970)) and known additives may be used.

The container member in this invention should just be a member which can form the container which has an opening part by joining each member. For example, the member which a container is obtained by joining a pair of members may be sufficient, and the member further divided finely may be sufficient. As the number of members increases, the number of joints increases and the process becomes complicated, and thus a pair of members is preferable.
The manufacturing method of a container member is not specifically limited, It can manufacture by injection molding, press molding, etc.

The container member used in the present invention may be a multilayer container member. For example, it is preferable to use a multilayer container member in which an olefin resin layer and a barrier resin layer are laminated from the viewpoint of the barrier property of the resulting container.
Examples of the barrier resin include polyvinyl alcohol polymers, ethylene-vinyl alcohol copolymers, polyamide resins, and aliphatic polyketones.

When a multilayer container member in which an olefin resin layer and a barrier resin layer are laminated is used as the container member, a member having an adhesive resin layer between the two layers is preferably used. Such a multilayer container member has a high interlayer strength between the olefin-based resin layer and the barrier resin layer, so that a container having excellent barrier properties and strength can be obtained.
Examples of the adhesive resin include modified polyolefin, polyurethane resin, and polyester resin. As the modified polyolefin, a carboxylic acid-modified polyolefin, particularly maleic anhydride-modified polyolefin is preferably used.
When a multilayer container member in which an olefin resin layer and a barrier resin layer are laminated is used as the container member, it is preferable to use the container member so that the barrier resin layer is close to the inside of the container.

In the step (2) of the present invention, at least the inner surface of each container member obtained in the step (1) includes a hydroxyl group and a carboxyl group in a hydroxyl group: carboxyl group = 30: 70 to 95: 5 (number ratio). It is a step of forming a film by applying a coating liquid containing the coalesced component (A) and a liquid medium.
The inner surface of the container member is a surface that becomes the inner side of the container when the container members are joined to each other, and a surface that comes into contact with the content when the content is injected into the container. .

The polymer component (A) containing a hydroxyl group and a carboxyl group may be a polymer component containing a hydroxyl group and a carboxyl group in one molecule, or a polymer component containing a hydroxyl group and a polymer component containing a carboxyl group. The polymer component containing these may be sufficient.
Examples of the polymer component containing a hydroxyl group and a carboxyl group in one molecule include a vinyl alcohol-acrylic acid copolymer and a vinyl alcohol-methacrylic acid copolymer. By controlling the copolymerization ratio, a polymer component (A) containing a hydroxyl group and a carboxyl group in a hydroxyl group: carboxyl group = 30: 70 to 95: 5 (number ratio) can be obtained.
Examples of the polymer component containing a hydroxyl group include polyvinyl alcohol polymers and polysaccharides. Examples of the polymer component containing a carboxyl group include polyacrylic acid, polymethacrylic acid, a polyacrylic acid partial neutralized product, and a polymethacrylic acid partial neutralized product. By controlling the mixing ratio of these two kinds of polymer components, a polymer component (A) containing a hydroxyl group and a carboxyl group in a hydroxyl group: carboxyl group = 30: 70 to 95: 5 (number ratio) is used. Can do.
Since it is easy to control the ratio between the hydroxyl group and the carboxyl group contained in the polymer component (A), the polymer component (A) is a mixture of a polymer component containing a hydroxyl group and a polymer component containing a carboxyl group. It is preferable to use it.

The polymer component containing a hydroxyl group used in the present invention is most preferably a polyvinyl alcohol polymer (A-1) because it can be dissolved in an aqueous liquid medium and is easy to handle. The polyvinyl alcohol polymer (A-1) is a polymer having a vinyl alcohol monomer unit as a main component. Examples of such “polyvinyl alcohol” include polymers obtained by hydrolyzing the acetate portion of vinyl acetate polymers, vinyl trifluoroacetate polymers, vinyl formate polymers, vinyl pivalate polymers, t- Examples include polymers obtained by hydrolyzing butyl vinyl ether polymers, trimethylsilyl vinyl ether polymers, etc. (For details on “polyvinyl alcohol”, see, for example, “Poval World”, “PVA World”, 1992, Kokai Co., Ltd. Molecular publication society; Nagano et al., “Poval”, 1981, see Kobunshi Shuppankai). The degree of “saponification” of the ester portion of the polymer is preferably 70 mol% or more, more preferably 85 mol% or more, and more preferably 98% mol or more of a so-called completely saponified product. Moreover, as for the polymerization degree of the polyvinyl alcohol-type polymer (A-1) to be used, it is more preferable that they are 100 or more and 5000 or less, and 200 or more and 3000 or less.

Also, as the polyvinyl alcohol polymer (A-1), so-called polyvinyl alcohol derivatives having a functional group other than a hydroxyl group can be used. Examples of the functional group other than a hydroxyl group include an amino group, a thiol group, a carboxyl group, a sulfone group, and a phosphorus group. Examples include acid groups, carboxylate groups, sulfonate ion groups, phosphate ion groups, ammonium groups, phosphonium groups, silyl groups, siloxane groups, alkyl groups, allyl groups, fluoroalkyl groups, alkoxy groups, carbonyl groups, and halogen groups. . A part of hydroxyl groups in PVA may be replaced with one or more of these functional groups.

The polymer component (A-2) containing a carboxyl group in the present invention is selected from the group consisting of polyacrylic acid, polymethacrylic acid, a polyacrylic acid partial neutralized product, and a polymethacrylic acid partial neutralized product. The polymer component is preferably at least one species. A copolymer of acrylic acid and methacrylic acid can also be used. The average molecular weight of the polymer component (A-2) containing a carboxyl group is preferably in the range of 2,000 to 5,000,000, more preferably 100,000 to 5,000,000.

The polyacrylic acid partial neutralized product or the polymethacrylic acid partial neutralized product can be usually obtained by adding an alkali component such as sodium hydroxide to an aqueous solution of polyacrylic acid or polymethacrylic acid. By adjusting the amount ratio of polyacrylic acid or polymethacrylic acid and alkali, a desired degree of neutralization can be achieved. The polyacrylic acid partial neutralized product and the polymethacrylic acid partial neutralized product preferably have a degree of neutralization calculated by the following formula of 0.1% to 20%.
Degree of neutralization = (A / B) × 100
A: Total number of moles of neutralized carboxyl groups contained in 1 g of polyacrylic acid or polymethacrylic acid B: Total number of moles of carboxyl groups before neutralization contained in 1 g of polyacrylic acid or polymethacrylic acid

The number ratio of the hydroxyl group and the carboxyl group contained in the polymer component (A) is hydroxyl group: carboxyl group = 30: 70 to 95: 5, preferably 70:30 to 95: 5. Moreover, it is preferable that the total weight of the hydroxyl group and carboxyl group which are contained in a polymer component (A) is 30 to 60%, More preferably, it is 35 to 55%. The total weight of the hydroxyl group and the carboxyl group is a value when the weight of the polymer component (A) is 100% by weight.

The number ratio between the hydroxyl group and the carboxyl group contained in the polymer component (A) can be determined by a known NMR method, IR method or the like. For example, in the case of the IR method, a calibration curve can be obtained and calculated using a sample having a known number ratio of hydroxyl groups to carboxyl groups. When a vinyl alcohol homopolymer and an acrylic acid monopolymer and / or a methacrylic acid monopolymer are used, the number of moles of hydroxyl groups and carboxyl groups can be determined in advance from the weight, and the number ratio can be calculated. The total weight measurement of the hydroxyl group and carboxyl group contained in the polymer component (A) can be determined by a known NMR method, IR method, etc., as with the number ratio. For example, in the case of the IR method, a calibration curve can be obtained and calculated for a polyol polymer having a known number of polyol units and a polycarboxylic acid polymer having a known number of polycarboxylic acid units. Moreover, when using a vinyl alcohol single polymer and an acrylic acid single polymer and / or a methacrylic acid single polymer, the weight of a hydroxyl group and a carboxyl group can be calculated | required from the weight previously, and this total amount can be used.

The polymer component (A) in the present invention is composed of 95 to 5% by weight of a polyvinyl alcohol polymer (A-1), polyacrylic acid, polymethacrylic acid, a polyacrylic acid partial neutralized product, and a polymethacrylic acid part. It is preferably a mixture of 5 to 95% by weight of one or more polymers (A-2) selected from the group consisting of neutralized products. However, this ratio is a value when the weight of the polymer component (A) contained in the coating liquid is 100%. The ratio of the polyvinyl alcohol polymer (A-1) to the polymer (A-2) is more preferably 50 to 95% for (A-1) and 5 to 50% for (A-2). More preferably, (A-1) is 70 to 90% and (A-2) is 10 to 30%.

The coating liquid in this invention contains an above described polymer component (A) and a liquid medium. The liquid medium is not particularly limited, but is preferably a liquid medium capable of dissolving the polymer component (A) from the viewpoint of coatability. Further, it is necessary that the liquid medium hardly remains in the barrier layer of the finally obtained barrier container. Therefore, it is preferable that the liquid medium is easy to remove.
Further, as will be described later, when the coating liquid contains a clay mineral (C), it is preferable to use a liquid medium in which the clay mineral swells and is easily cleaved.

Examples of the liquid medium used in the present invention include water, water, alcohols (methanol, ethanol, propanol, isopropanol, ethylene glycol, diethylene glycol, and the like), dimethylformamide, dimethyl sulfoxide, acetone, and the like. A water-alcohol mixture is preferably used.

The coating solution preferably further contains an alkali metal ion (B) in addition to the polymer component (A) and the liquid medium. By using such a coating liquid, a container having further excellent barrier properties can be obtained.
Examples of the alkali metal ion (B) in the present invention include sodium ion, lithium ion, and potassium ion. The weight of the alkali metal ion (B) contained in the coating liquid is not particularly limited, but is preferably 0.2 to 100 parts by weight of the polymer component (A) contained in the coating liquid. 5 parts, more preferably 0.2 to 2 parts.

The alkali metal ion (B) is derived from an alkali metal ion donating compound. That is, the coating solution contains an alkali metal ion donating compound. Examples of the alkali metal ion donating compound include sodium hydroxide, sodium hypophosphite, lithium hydroxide, potassium hydroxide and the like. When a partially neutralized polyacrylic acid obtained by adding sodium hydroxide to a polyacrylic acid aqueous solution is used as the polymer component (A), the partially neutralized polyacrylic acid is donated with alkali metal ions. Acts as a compound.
Examples of the alkali metal ion donating compound include clay mineral (C) having an alkali metal ion between layers. Two or more kinds of alkali metal ion donor compounds may be used in combination. From the viewpoint of the barrier properties of the resulting container, the coating liquid preferably contains a clay mineral (C) having an alkali metal ion (B) between the layers.

The clay mineral is a compound having a layered structure in which unit crystal layers are usually stacked in a raw material state. Here, the layered structure refers to a structure in which surfaces in which atoms are strongly bonded by a covalent bond or the like and densely arranged are stacked substantially in parallel by a weak binding force such as van der Waals force. Examples of the clay mineral include montmorillonite, beidellite, nontronite, saponite, soconite, stevensite, hectorite, tetrasilic mica, sodium teniolite, muscovite, phlogopite, and the like. In addition, those obtained by treating these clay minerals with an organic substance such as ion exchange to improve dispersibility (see Asakura Shoten, “Clay Dictionary”) can also be used as clay minerals containing alkali metal ions.

From the viewpoint of dispersibility in the coating liquid, it is particularly preferable to use a clay mineral (C) having a property of swelling and cleaving in a liquid medium. An example of such a clay mineral is montmorillonite having sodium ions between layers.
The degree of the property that the clay mineral swells and cleaves in the solvent can be evaluated by the following test. The swelling property of the clay mineral is preferably 5 or more, more preferably 20 or more in the following swellability test. On the other hand, the cleaving property of the clay mineral is preferably 5 or more, more preferably 20 or more in the following cleaving test.

(Swellability test)
Place 100 ml of liquid medium in a 100 ml graduated cylinder and gradually add 2 g of clay mineral. After standing at 23 ° C. for 24 hours, the volume (ml) of the clay mineral dispersion layer is read from the scale of the interface between the clay mineral dispersion layer and the supernatant in the graduated cylinder. It shows that swelling property is so high that this numerical value (swelling value) is large.

[Cleavage test]
Gradually add 30 g of clay mineral into 1,500 ml of liquid medium, disperser (Asada Tekko Co., Ltd., Despa MH-L, blade diameter 52 mm, rotation speed 3,100 rpm, container capacity 3 L, bottom-blade distance 28 mm ) At 90 ° C. for 90 minutes at a peripheral speed of 8.5 m / min, and 100 ml of this dispersion is taken into a graduated cylinder. After standing for 60 minutes, the volume (ml) of the clay mineral dispersion layer is read from the scale of the interface between the clay mineral dispersion layer and the supernatant in the graduated cylinder. The larger this numerical value (cleavage value), the higher the cleavage property.

The clay mineral (C) preferably has an aspect ratio of 30 to 3,000, more preferably 30 to 1,500, from the viewpoint of dispersibility in the coating liquid and barrier properties of the resulting container.
The aspect ratio (Z) of the clay mineral is defined by the formula: Z = L / a. In the formula, L is the average particle diameter of the clay mineral, a is the unit thickness of the clay mineral, that is, the thickness of the unit crystal layer of the clay mineral, and is determined by the powder X-ray diffraction method (“Guide to Instrumental Analysis ( a) "(1985, published by Kagaku Dojinsha, supervised by Jiro Shiokawa, p. 69).

The average particle diameter of the clay mineral is a particle diameter (volume-based median diameter) obtained by a diffraction / scattering method in a liquid medium. That is, from the diffraction / scattering pattern obtained when light passes through the clay mineral dispersion, it can be obtained by calculating the particle size distribution most consistent with the diffraction / scattering pattern by Mie scattering theory or the like. . Specifically, for example, the measurement range of the particle size distribution is divided into appropriate sections, the representative particle diameter is determined for each section, and the particle size distribution, which is originally a continuous quantity, is converted into a discrete quantity and calculated. A method is mentioned.

The amount of the clay mineral (C) contained in the coating liquid is not particularly limited, but from the viewpoint of the barrier properties of the resulting container, the polymer component (A) containing a hydroxyl group and a carboxyl group and the clay mineral ( The volume ratio of C) is preferably (A) / (C) = 50/50 to 99/1, and more preferably 70/30 to 99/1.

It is preferable to add a surfactant to the coating solution. A film formed by applying such a coating solution has excellent adhesion to the container member. The content of the surfactant is usually 0.001 to 5% by weight in 100% by weight of the coating liquid.

As the surfactant, a known surfactant such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant can be used. In particular, an alkali metal salt of a carboxylic acid having an alkyl chain having 6 to 24 carbon atoms, an ether type nonionic surfactant such as a polydimethylsiloxane-polyoxyethylene copolymer (silicone nonionic surfactant) ) Or a fluorine-type nonionic surfactant (fluorine-based nonionic surfactant) such as a perfluoroalkylethylene oxide compound is preferable from the viewpoint of improving adhesion.

Further, known additives such as antioxidants, ultraviolet absorbers, light stabilizers, antiblocking agents and the like can be added to the coating liquid according to the purpose and application. These additives may be used alone or in combination of two or more.
Further, when the coating liquid contains clay mineral, it is preferable to use the clay mineral uniformly dispersed by high-pressure dispersion treatment.

In the step (2), the coating liquid is applied to at least the inner surface of each container member to form a film. Examples of the method for applying the coating liquid to the container member include a dipping method and a spray coating method. When the member is flat, gravure method such as direct gravure method, reverse gravure method, roll coating method such as two roll beat coating method, bottom feed three reverse coating method, doctor knife method, die coating method, bar The coating liquid can also be applied by a method such as a coating method. The film thickness of the film formed by applying the coating liquid is usually 1 to 50 μm as the thickness of the barrier layer in the obtained barrier container.

For the purpose of improving the adhesion between the container member and the membrane, it is preferable to surface-treat the container member in advance. Examples of the surface treatment method include corona treatment, ozone treatment, plasma treatment, electron beam radiation treatment, acid treatment, anchor coat treatment, primer treatment, and intro treatment. These treatments may be performed alone or in combination of two or more.

Step (3) of the present invention is a step of obtaining a primary container by joining container members each having a film formed at least on the inner surface. A film containing the polymer component (A) and the liquid medium is formed on the inner surface of the container member obtained in the step (2) by applying a coating liquid containing the polymer component (A) and the liquid medium. ing. In the step (3), a container member obtained by removing the liquid medium from the film containing the polymer component (A) and the liquid medium may be used, and the polymer obtained in the step (2) without removing the liquid medium. You may use the container member in which the film | membrane containing a component (A) and a liquid medium was formed as it is. In the former case, it is necessary to heat and pressurize when joining the container members. In the latter case, when a container member having a film formed on the bonding surface is used, the members can be bonded to each other without applying pressure by removing the liquid medium. Therefore, it is preferable to use a container member in which a film containing a liquid medium is formed on the inner surface and the bonding surface. Examples of the method for removing the liquid medium include a method of drying at 100 ° C. or lower, usually about 30 to 80 ° C. The removal of the liquid medium is preferably performed under a condition where the water vapor concentration is less than 50 g / m ³ .

Examples of a method for bonding container members include a method of heating and pressurizing bonding surfaces, that is, a method of heat sealing. Further, a flange for joining may be provided in advance on the container member, and the flanges may be heat sealed. In this case, the flange becomes the joint surface. The conditions for normal heat sealing are that the temperature is equal to or higher than the melting point of the thermoplastic resin, the time is 1 second to 1 hour, and the pressure is 0.001 kg / cm ^{2 to} 100 kg / cm ² . As described above, when a container member in which a film containing a liquid medium is formed on the inner surface and the bonding surface is used, bonding is performed without applying pressure only by removing the liquid medium by joining the bonding surfaces together. And is excellent in production efficiency.

Step (4) of the present invention is a step of dry-heating the primary container. By performing the dry heat treatment, the hydroxyl group and the carboxyl group of the polymer component (A) contained in the film formed by applying the coating liquid react to form a barrier layer. When the liquid medium is contained in the film, the liquid medium can be removed by dry heat treatment. The dry heat treatment conditions are a water vapor concentration of less than 50 g / m ³ and a temperature of 100 ° C. or higher, preferably a water vapor concentration of 0 to 40 g / m ³ and a temperature of 120 ° C. or higher and 200 ° C. or lower. The time for the dry heat treatment is usually 1 second to 1 hour.
In the present invention, in the container member in which a film is formed on the inner surface obtained in the step (2), the reaction between the hydroxyl group and the carboxyl group of the polymer component (A) contained in the film does not proceed. Even if a film is formed on the surface, bonding is possible in the step (3). Further, even if no film is formed on the joint surface of the container member, the reaction of the polymer component (A) contained in the film proceeds in the step (4), so that the obtained container is also present at the interface between the container members. The container is formed with a strong barrier layer. That is, since the bonding is possible even if the bonding surface is covered with the film, it is not necessary to form the film with care so as not to cover the bonding surface with the film as in the prior art. Therefore, a container can be manufactured efficiently.

You may perform the process (3) and process (4) of this invention simultaneously. That is, the container members can be joined under the dry heat treatment conditions in the step (4). In particular, in the step (3), when the container member from which the liquid medium is removed from the film containing the polymer component (A) and the liquid medium obtained in the step (2) is used, the container members are joined together under dry heat treatment conditions. By doing so, the production efficiency of a container can be improved.

Furthermore, in the present invention, after the step (4), a step of performing a wet heat treatment may be further included as a step (5). The wet heat treatment is a treatment for holding in an atmosphere having a water vapor concentration of more than 290 g / m ³ at a temperature of 100 ° C. or higher or in water of 80 ° C. or higher. The time for the wet heat treatment is usually 1 second to 1 hour. If the water vapor concentration at 100 ° C. above the temperature of the treatment in an atmosphere of 290 g / m ³ greater, the temperature is preferably in the range of 120 to 200 [° C., the water vapor concentration is preferably in the range of 500~20000g / m ^3. By performing the wet heat treatment, the container can be further improved in barrier properties.
There is no restriction | limiting in particular in the thickness of the container obtained by this invention, Usually, it is the range of 0.5-10 mm.

The container obtained by the present invention can be suitably used as a tank for storing various organic solvents such as gasoline. In particular, it is suitable as a fuel tank for automobiles.

Hereinafter, the present invention will be described based on examples. First, a method for measuring physical property values in the following examples will be described. In the following examples, a film was used as the container member.
[Thickness measurement]
The measurement was performed using a commercially available digital thickness gauge (contact thickness gauge, trade name: ultra-high precision deci micro head MH-15M, manufactured by Nippon Optical Co., Ltd.).

(Particle size measurement)
Measurement was performed using a laser diffraction / scattering particle size distribution analyzer (LA910, manufactured by Horiba, Ltd.). The average particle size of the clay mineral in the coating liquid (1) to be described later is measured with a paste cell at an optical path length of 50 μm, and the average particle size of the clay mineral in the diluted solution of the coating liquid (1) is measured by the flow cell method. The measurement was performed at an optical path length of 4 mm. In either case, the average particle size did not change, and it was confirmed that the clay mineral was sufficiently swollen and cleaved in the dispersion. This value was regarded as the average particle size L of the clay mineral.

[Measurement of the number ratio of hydroxyl groups and carboxyl groups contained in the polymer component (A)]
Polyvinyl acid (completely saponified product) was used as the polymer component (A-1) containing a hydroxyl group, and polyacrylic acid was used as the polymer component (A-2) containing a carboxyl group. From the following formula, the number of hydroxyl groups in polyvinyl alcohol and the number of carboxyl groups in polyacrylic acid were calculated, and the ratio was determined.
Number of hydroxyl groups = (Polymer component (A-1) addition amount) / (Molecular weight per monomer unit constituting polymer component (A-1))
Number of carboxyl groups = (addition amount of polymer component (A-2)) / (molecular weight per unit of monomer unit constituting polymer component (A-2))

[Total weight measurement of hydroxyl group and carboxyl group contained in polymer component (A)]
Polyvinyl acid (completely saponified product) was used as the polymer component (A-1) containing a hydroxyl group, and polyacrylic acid was used as the polymer component (A-2) containing a carboxyl group. The amount of hydroxyl group and the amount of carboxyl group were calculated from the following formulas and totaled.
Hydroxyl amount = (17 / (molecular weight per unit of monomer unit constituting polymer component (A-1))) × (polymer component (A-1) addition amount / polymer component (A) addition amount) × 100
Carboxyl group amount = (45 / (molecular weight per unit of monomer unit constituting polymer component (A-2))) × (polymer component (A-2) addition amount / polymer component (A) addition amount) × 100

[Measurement of alkali metal ion concentration]
Using an inductively coupled plasma emission spectrometer (Optima 3000, manufactured by Perkin Elmer), measure the sodium ion concentration of the entire container member having the barrier layer, and apply a coating solution to the layers other than the film formed from it. The sodium ion concentration in the membrane was determined by subtracting the sodium ion concentration contained. The sample preparation method is as follows. 1 g each of the container member and the container member having the barrier layer was sampled, 1 ml of 96% sulfuric acid was added, and then ashed with an electric furnace, and the remaining residue was dissolved in 5% hydrochloric acid and fixed. The constant volume of the solution was used in an inductively coupled plasma emission spectrometer, the sodium ion concentration was measured, and the difference was determined.

[Aspect ratio calculation]
Using an X-ray diffractometer (XD-5A, manufactured by Shimadzu Corporation), diffraction measurement of the clay mineral was performed by the powder method, and the unit thickness a of the clay mineral was determined. Using the average particle diameter L obtained by the above method, the aspect ratio Z of the clay mineral was calculated by the formula Z = L / a. In addition, about the thing which dried coating liquid (1), the X-ray-diffraction measurement was also performed and it confirmed that the surface interval of the clay mineral was spreading.

[Humid heat treatment]
Using a small retort high-pressure steam sterilizer (RK-3030, manufactured by Alp Co., Ltd.), the container member was wet-heat treated in a steam atmosphere at 120 ° C. for a predetermined time. Humidity is considered 100% RH.

[Drying treatment]
The container member was allowed to stand for 24 hours in an atmosphere of 23 ° C. and 50% RH (water vapor concentration of 10 g / m ³ ).

(Bonding strength measurement)
The bonding strength was measured by T-peeling in an atmosphere of 23 ° C. and 50% RH at a peeling width of 15 mm and a peeling speed of 300 mm / min.

[Preparation of coating solution]
(1) Preparation of coating liquid (1) Dispersion kettle (trade name: Despa MH-L, manufactured by Asada Tekko Co., Ltd.), ion-exchanged water (specific electrical conductivity 0.7 μs / cm or less) 1300 g and polyvinyl Alcohol (PVA117H; manufactured by Kuraray Co., Ltd., degree of saponification; 99.6%, degree of polymerization 1,700) was mixed with 130 g, and the temperature was raised to 95 ° C. under low speed stirring (1500 rpm, peripheral speed 4.1 m / min). Warm up. The mixed system was stirred at the same temperature for 30 minutes to dissolve the polyvinyl alcohol, and then cooled to 60 ° C. to obtain an aqueous polyvinyl alcohol solution. While stirring the polyvinyl alcohol aqueous solution (60 ° C.) under the same conditions as described above, an alcohol aqueous solution obtained by mixing 122 g of 1-butanol, 122 g of isopropyl alcohol and 520 g of ion-exchanged water was added dropwise over 5 minutes. After completion of the dropping, switching to high-speed stirring (3,000 rpm, peripheral speed = 8.2 m / min), 82 g of high-purity montmorillonite (trade name: Kunipia G; manufactured by Kunimine Industries Co., Ltd.) was gradually added to the stirring system, After completion of the addition, stirring was continued at 60 ° C. for 60 minutes. Thereafter, 243 g of isopropanol was further added over 15 minutes, and then the mixed system was cooled to room temperature to obtain a clay mineral-containing liquid (1).
Non-ionic surfactant (polydimethylsiloxane-polyoxyethylene copolymer, trade name: SH3746, manufactured by Toray Dow Corning Co., Ltd.) 0.1% by weight based on this clay mineral-containing liquid (1) (Based on the weight of the dispersion) is added under low speed stirring (1500 rpm, peripheral speed 4.1 m / min), and then adjusted with an ion exchange resin so that the pH of the system is 6, and a clay mineral dispersion ( 1) was prepared.
Furthermore, another dispersion kettle (trade name: Despa MH-L, manufactured by Asada Tekko Co., Ltd.), 1067 g of ion-exchanged water (specific electric conductivity 0.7 μs / cm or less) and polyacrylic acid (Wako Pure Chemical Industries, Ltd.) (Made by Co., Ltd., average molecular weight 100,0000) 33 g was mixed, and a polymer component (A-2) solution was prepared at room temperature under low speed stirring (1500 rpm, peripheral speed 4.1 m / min).
2519 g of the clay mineral dispersion (1) and 1100 g of the polymer component (A-2) solution are gradually mixed under low speed stirring (1500 rpm, peripheral speed 4.1 m / min) to form a mixed solution. The coating liquid (1) was obtained by processing on the conditions of 1100 kgf / cm < ² > using the high voltage | pressure dispersion apparatus (Brand name: Super high pressure homogenizer M110-E / H, the product made from Microfluidics Corporation).
The cleaved montmorillonite average particle diameter L in the coating liquid (1) was 560 nm, the a value obtained from powder X-ray diffraction was 1.2156 nm, and the aspect ratio Z was 460.

(2) Preparation of coating liquid (2) A coating liquid (2) was obtained in the same manner as described above except that the high-purity montmorillonite was not added.

[Example 1]
An unstretched polypropylene (CPP) film (trade name: Pyrene film P1111; manufactured by Toyobo Co., Ltd.) having a thickness of 50 μm and subjected to corona treatment was used as a member. The above-mentioned coating liquid (1) is coated on the corona-treated surface of the member by a microgravure coating method (number of gravure roll lines # 150 (#: GM)) using a test coater (manufactured by Yasui Seiki). By gravure coating at a speed of 3 m / min and drying at 100 ° C., a member (1 ′) having a film formed on one surface of the member was obtained. The thickness of the film was 2.0 μm, and the Na concentration in the film was 7000 ppm. Two obtained members (1 ′) were used, and the film surfaces were superposed and heat-sealed and joined. For heat sealing, a heat sealer (manufactured by FUJI IMPULSE T230: manufactured by FUJI IMPULSE CO. LTD) was used, and heat sealing was performed for 10 minutes at a temperature of 150 ° C., a pressure of 1 kg / cm ² , and a heat sealing width of 20 mm. Thereafter, aging was performed for 24 hours in an atmosphere of 23 ° C. and 50% RH (water vapor concentration: 10 g / m ³ ) to obtain a member (1 ″). The member (1 ″) corresponds to the primary container in the present invention. Next, the member (1 ″) was subjected to a wet heat treatment for 60 minutes and further subjected to a drying treatment to obtain a laminate (1). The laminate (1) corresponds to the container in the present invention. The bonding strength of the laminate (1) was measured. The results are shown in Table 1.

[Example 2]
A laminate (2) was obtained in the same manner except that the coating liquid (2) was used instead of the coating liquid (1). The bonding strength of the laminate (2) was measured. The results are shown in Table 1.
Example 3
A laminate (3) was obtained in the same manner as in Example 2 except that the wet heat treatment was not performed. The bonding strength of the laminate (3) was measured. The results are shown in Table 1.
Example 4
An unstretched polypropylene (CPP) film (trade name: Pyrene film P1111; manufactured by Toyobo Co., Ltd.) having a thickness of 50 μm and subjected to corona treatment was used as a member. Gravure is applied to the corona-treated surface of the member by a microgravure coating method (number of gravure roll lines # 150 (#: GM)) using a test coater at a coating speed of 3 m / min. The film was formed by coating. Without performing the drying treatment, the members were overlapped with each other while the film contained the liquid medium, and the drying treatment was performed at 50 ° C. for 24 hours. Then, using a heat sealer (FUJI IMPULSE T230: manufactured by FUJI IMPULSE CO.LTD), heat sealing was performed for 10 minutes at a temperature of 150 ° C., a pressure of 1 kg / cm ² , and a heat sealing width of 20 mm to obtain a laminate (4). . The bonding strength of the laminate (4) was measured. The results are shown in Table 1. In addition, after performing the drying process for 50 degreeC for 24 hours, when the joining strength was measured also about the member overlap | superposed before heat sealing, it peeled similarly to after heat sealing, and it joined with sufficient high intensity | strength.

As a reference example, the results of measuring the oxygen permeability, that is, the oxygen barrier property of a laminate having a film having the same composition as the barrier layer of the container obtained by the present invention are shown below. From this result, it can be seen that the members of the above-described examples are also excellent in barrier properties.
[Reference Example 1]
A biaxially stretched nylon (ONy) film (trade name: ON-U; manufactured by Unitika Ltd.) having a thickness of 15 μm and subjected to corona treatment was used as a base material layer. The above coating liquid (1) is applied to the corona-treated surface of the base material layer by a microgravure coating method (gravure roll wire number # 150 (#: GM)) using a test coater (manufactured by Yasui Seiki). Gravure coating was performed at a coating speed of 3 m / min and dried at 100 ° C. to obtain a member (5 ′) in which a film was laminated on a base material layer. The thickness of the film was 0.4 μm, and the Na concentration in the film was 0.7%. The obtained member (5 ′) was subjected to a dry heat treatment and then aged for 24 hours in an atmosphere of 23 ° C. and 50% RH. Next, the laminate was subjected to a wet heat treatment for 60 minutes, and further subjected to a drying treatment. Thereafter, the oxygen permeability of the laminate (5) was measured. The results are shown in Table 2.
[Reference Examples 2 and 3]
A laminated body was obtained in the same manner as in Reference Example 1 except that a coating liquid in which the amount of clay mineral added was adjusted so that the sodium ion concentration in the membrane was as shown in Table 2, and the oxygen permeability was adjusted. It was measured.
[Reference Examples 4 and 5]
A laminate was obtained in the same manner as in Reference Example 1 except that the wet heat treatment conditions were as shown in Table 2, and the oxygen permeability was measured.

※１ 乾熱処理条件 ： １５０℃、水蒸気濃度５ｇ／ｍ³のオーブン中で６０分間静置した。

* 1 Dry heat treatment conditions: It was left still for 60 minutes in an oven at 150 ° C. and a water vapor concentration of 5 g / m ³ .

As a reference example, the results of measuring gasoline permeability, that is, gasoline barrier properties, for a laminate having a film having the same composition as the barrier layer of the container obtained by the present invention are shown below. From this result, it can be seen that the members of the above-described examples are also excellent in gasoline barrier properties.
[Method for evaluating gasoline barrier properties]
4.6 g of gasoline (manufactured by Nippon Oil Co., Ltd., ENEOS regular gasoline) was placed in a cup (manufactured by Duralumin, capacity 11.3 cc). The opening of the cup was covered so that the barrier layer side of the evaluation film was in contact with the cup opening. The area of the lid (area through which gasoline can permeate) was 1.133 × 10 ⁻³ m ² . The weight of the capped cup was measured (W1). After the weight-measured cup was stored at 60 ° C. for 96 hours, the weight was measured (W2), and the gasoline permeability (g / m ² · 24 hr) was determined from the reduction amount (W1-W2).

[Reference Example 6]
An unstretched polypropylene (CPP) film (trade name: Pyrene film P1111; manufactured by Toyobo Co., Ltd.) having a thickness of 50 μm and subjected to corona treatment was used as a member. The above-mentioned coating liquid (1) is coated on the corona-treated surface of the member by a microgravure coating method (number of gravure roll lines # 150 (#: GM)) using a test coater (manufactured by Yasui Seiki). A member (6 ′) having a film formed on one surface of the member was obtained by gravure coating at a speed of 3 m / min and drying at 100 ° C. The thickness of the film was 2.0 μm, and the Na concentration in the film was 7000 ppm. The member (6 ′) obtained was subjected to a dry heat treatment at a temperature of 150 ° C. for 10 minutes, then aged for 24 hours in an atmosphere of 23 ° C. and 50% RH, then subjected to a wet heat treatment for 60 minutes, and further subjected to a drying treatment. A laminate (6) was obtained. The gasoline permeability of the laminate (6) was measured. The results are shown in Table 3.
[Reference Example 7]
The member (6 ′) obtained in Reference Example 6 was subjected to a dry heat treatment at a temperature of 150 ° C. for 10 minutes, and then aged in an atmosphere of 23 ° C. and 50% RH for 24 hours to obtain a laminate (7). The gasoline permeability of the laminate (7) was measured. The results are shown in Table 3.
[Reference Example 8]
The gasoline permeability of a film (8) obtained by corona treatment on one side of a 50 μm-thick unstretched polypropylene (CPP) film (trade name: Pyrene Film P1111; manufactured by Toyobo Co., Ltd.) was measured. The results are shown in Table 3. When evaluating the gasoline barrier property, the corona-treated surface was in contact with the cup opening.

Claims (7)

A method for producing a barrier container having the following steps, wherein the container members are joined to each other and have a barrier layer on at least the inner surface.
(1) Step of molding a container member made of a thermoplastic resin (2) At least the inner surface of each container member obtained in step (1) has a hydroxyl group and a carboxyl group, hydroxyl group: carboxyl group = 30: 70 to 95: A step of applying a coating liquid containing a polymer component (A) containing 5 (number ratio) and a liquid medium, and forming a film (3) joining container members formed with a film on at least the inner surface Step for obtaining primary container (4) Step for dry heat treatment of primary container The manufacturing method of the barrier container of Claim 1 which has the following processes (5) after a process (4) in the manufacturing method of the barrier container of Claim 1.
(5) Step of wet heat treatment The method for producing a barrier container according to claim 1 or 2, wherein in the step (2), the coating liquid is applied to an inner surface and a joint surface of each container member to form a film. The polymer component (A) is a polyvinyl alcohol polymer (A-1) 95 to 5% by weight, polyacrylic acid, polymethacrylic acid, polyacrylic acid partial neutralized product, and polymethacrylic acid partial neutralized product. The method for producing a barrier container according to any one of claims 1 to 3, which is a mixture of 5 to 95% by weight of one or more polymers (A-2) selected from the group consisting of products. The method for producing a barrier container according to any one of claims 1 to 4, wherein the coating liquid further contains an alkali metal ion (B). The method for producing a barrier container according to claim 5, wherein the weight of the alkali metal ion (B) contained in the coating liquid is 0.2 to 5 parts with respect to 100 parts by weight of the polymer component (A). The manufacturing method of the barrier container in any one of Claims 1-6 in which the said coating liquid contains the clay mineral (C) which has an alkali metal ion (B) between layers.