WO2021156908A1 - Double structure - Google Patents

Abstract

A double structure 100 comprises: a first molded body 101; and a second molded body 103 that is superimposed on the first molded body. The double structure is characterized in that at least the first molded body 101 is made from plastic, and in that a barrier coating 105, which can be removed by washing with water, is present between the first molded body 101 and the second molded body 103.

Description

Double structure

The present invention relates to a double structure, and particularly to a double structure having excellent recyclability.

In recent years, plastics have been used for various purposes because they can be easily formed into various shapes. However, plastic products are inferior in gas barrier properties to metal products and glass products.
For this reason, in plastic products used for applications that require barrier properties against oxygen and the like, such as packaging materials for containers and films, a layer of passive barrier materials such as ethylene / vinyl alcohol copolymer resin is used. A multi-layer structure has been introduced.
On the other hand, recently, active barrier materials such as oxidizable organic compounds have been developed (see, for example, Patent Document 1), and have come to be used in the field of packaging materials and the like.
In addition, it may be used with light-shielding properties by coloring it for the purpose of light barrier.

However, the packaging material and the colored resin whose gas barrier property is enhanced by the above-mentioned barrier material have a drawback that they are difficult to recycle and are difficult to reuse.
That is, in a container having a multi-layer structure having a barrier layer using the barrier material as described above, this barrier material cannot be separated from other container material resins (for example, PET or polyolefin), and similarly, a colorant. However, it cannot be separated from the container material resin, making it difficult to reuse these material resins. Barrier technology that considers the reusability of the material resin has hardly been studied.

For example, recently, a double-structured container having a double-structured structure consisting of an inner container and an outer container has been put into practical use as an airless container in which a seasoning liquid such as soy sauce is stored. Such a double-structured container is used in combination with a cap with a check valve, and is filled in the inner container by squeezing and denting the body wall of the bottle, which is the outer container, from the outside. When the contents are discharged from the injection path formed in the cap and the discharge of the contents is completed by stopping the pressing of the body wall of the bottle, the air is introduced into the inner container by the action of the check valve. Instead, it is introduced into the space between the inner container and the outer container through a flow path different from the pouring path of the cap. As a result, the inner container shrinks by the amount that the contents are discharged, and each time the contents are discharged, the inner container shrinks. In a double-structured container in which the contents are discharged by such a method, the contents can be dispensed and air is effectively prevented from entering the inner container filled with the contents, so that the contents are oxidized. There is an advantage that deterioration can be effectively avoided and the freshness of the contents can be maintained for a long period of time.

Even in the above-mentioned double-structured container, since it is necessary to introduce air between the inner container and the outer container in order to discharge the contents, it is possible to impart an oxygen barrier property to the inner container. desired. For example, Patent Document 2 describes that when a preform for an inner container and a preform for an outer container are overlapped and stretch-molded to produce a container having a double structure, the preform for the inner container and the preform for the outer container are manufactured. A technique has been proposed in which a chemical that does not decompose at the stretching temperature, such as an organic oxygen absorber or a deodorant, is applied between the reform and the reform.
However, in such a technique, since the powdered drug is merely filled in the space between the inner container and the outer container, the adhesion between the drug and the inner container or the outer container is insufficient. In addition, such powdered chemicals have not been put into practical use because they hinder the reusability of the container material resin.

Japanese Unexamined Patent Publication No. 2018-21128 Japanese Unexamined Patent Publication No. 5-228988

Therefore, an object of the present invention is a double structure used in a state where two molded bodies are overlapped with each other, and the permeation of oxygen is effectively suppressed by the barrier material, and the barrier material can be easily removed. It is an object of the present invention to provide a double structure capable of effectively reusing a material such as a resin constituting each molded body.
Another object of the present invention is to provide a composition used in the formation of a barrier coating applied to the dual structure described above in order to suppress the permeation of oxygen.

According to the present invention
In a double structure composed of a first molded body and a second molded body superposed on the first molded body,
Provided is a double structure characterized in that at least the first molded body is made of plastic and a water-washable removable barrier coating is present between the first molded body and the second molded body. Will be done.

In the double structure of the present invention, the following aspects are preferably adopted.
(1) The barrier coating is provided on the first molded body side.
(2) The barrier coating is provided on the side of the second molded body.
(3) The barrier coating contains a water-soluble binder.
(4) The barrier coating has a structure in which a functional material for enhancing the oxygen blocking property of the water-soluble binder is dispersed in the water-soluble binder.
(5) The functional material is an oxidizable organic compound.
(6) The oxidizing organic compound has the following formula (1):

In the formula, ring X is an aliphatic ring having one unsaturated bond.
Y is an alkyl group,
Being at least one selected from the group consisting of an acid anhydride represented by, an ester derived from the acid anhydride, an amide, an imide or a dicarboxylic acid, and a polymer having a structural unit derived from the acid anhydride. ..
(7) The water-soluble binder is a polyvinyl alcohol polymer or a polycarboxylic acid polymer.
(8) The first molded body is an inner container, the second molded body is an outer container containing the inner container, and the barrier coating is provided on the outer surface of the inner container. thing.
(9) The first molded body is a preform for an inner container, the second molded body is a preform for an outer container containing the preform for the inner container, and the preform for the inner container is on the outer surface. , The barrier coating is provided and has a stack preform structure.

According to the present invention, a composition for forming a barrier coating containing an oxidizing organic compound and a water-soluble binder is provided.

In the composition for forming a barrier coating of the present invention,
(10) The oxidizable organic compound is contained in the range of 10 to 300 parts by mass per 100 parts by mass of the water-soluble binder.
(11) The water-soluble binder is a polyvinyl alcohol polymer or a polycarboxylic acid polymer.
Is preferable.

The double structure of the present invention is used by superimposing the second molded body on the first molded body made of plastic, and the second molded body is sandwiched between the first molded body and the second molded body. It has an important feature in that it has a barrier coating that can be removed by washing with water.
That is, this barrier coating is provided by coating the surface of the first molded product or the surface of the second molded product, whereby oxygen permeation to the first molded product can be effectively prevented. Moreover, this barrier coating can be easily removed from the used double structure by washing with water, and is separated into a first molded body and a second molded body. Therefore, by washing with water, these molded bodies or the materials forming these molded bodies can be easily reused.

The double-structured structure of the present invention can be effectively applied particularly to a double-structured container manufactured by the stack preform method. For example, a barrier coating is provided on the outer surface of the preform for an inner container, and this is applied to the outer container. By stretching blow molding the stack preform obtained by inserting and holding it inside the preform for use, a double-structured container having a barrier coating between the inner container and the outer container can be obtained. In such a double-structured container, the permeation of oxygen into the inner container is effectively prevented, and the freshness of the contents contained in the inner container can be more effectively maintained. Moreover, such a double-structured container can be easily removed from the barrier coating by washing with water in the recycling process, and is separated into an inner container and an outer container. Therefore, this double-structured container is excellent in recyclability because the resin material forming the inner container and the outer container can be easily reused.

The conceptual diagram for demonstrating the double structure of this invention. FIG. 6 is a schematic side sectional view immediately after molding of a double-structured container which is a preferable example of the double-structured structure of the present invention. FIG. 2 is a schematic side sectional view showing a first preform (preform for molding an outer container) and a second preform (preform for molding an inner container) used for manufacturing the double-structured container of FIG. Schematic side sectional view showing a stack preform in which a second preform is housed and held in a first preform.

With reference to FIG. 1, the double structure 100 of the present invention is formed by superimposing the second molded body 103 on the first molded body 101, but the first molded body 101. A barrier coating 105 is formed on the surface of the above. That is, the second molded body 103 is superposed on the barrier coating 105 of the first molded body 101.

<First molded body 101 and second molded body 103>
The first molded body 101 is made of plastic and may have an appropriate shape depending on its use. For example, when the first plastic molded product 101 is used for packaging or the like, it may have a form such as a film or a sheet depending on the form of the substance to be packaged, or the container may have a form such as a film or a sheet. It may have such a form. Further, the second molded body 103 is simply stacked and used without being adhered so as to cover the first molded body 101, and is used, for example, for simple packaging. The material is not particularly limited, and may be made of paper, metal foil, or the like. However, in general, depending on the form of the first molded body 101, it can be easily molded into a form that covers the first molded body 101. Like the first molded product 101, it is preferably made of plastic. Further, a film or sheet having the form of the double structure 100 of the present invention in which the barrier coating 105 that can be removed by washing with water is provided between the first molded body 101 and the second molded body 103. By subjecting the molded product to a means such as vacuum forming, pressure molding, overhang molding, plug assist molding, etc., a cup-shaped or tray-shaped container can be formed.

Generally, when used in the packaging field, it is preferable that the first molded body 101 and the second molded body 103 are formed of the following thermoplastic resin.
Olefin resins such as low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene (PP), poly 1-butene, poly 4-methyl Random or block copolymers of α-olefins such as -1-pentene or ethylene, propylene, 1-butene, 4-methyl-1-pentene, cyclic olefin copolymers, etc.;
Ethylene-vinyl acetate copolymers, for example, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ethylene-vinyl chloride copolymers, ion-crosslinked olefin copolymers (ionomers), etc.;
Styrene-based resins such as polystyrene, acrylonitrile / styrene copolymer, ABS, α-methylstyrene / styrene copolymer, etc .;
Vinyl-based resins such as polyvinyl chloride, polyvinylidene chloride, vinyl chloride / vinylidene chloride copolymer, methyl polyacrylate, polymethyl methacrylate, etc.;
Polyamide resin, for example, nylon 6, nylon 6-6, nylon 6-10, nylon 11, nylon 12, etc .;
Polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene furanoate (PEF), polytrimethylene furanoate (PTF) and copolymerized polyesters thereof and the like;
Polycarbonate resin;
Polyphenylene oxide resin;
Biodegradable resins such as polylactic acid (PLA), polybutylene succinate (PBS), polyhydroxyalkanoates (PHA) and copolymers thereof;
Of course, a blend of these thermoplastic resins can also be used as long as the moldability is not impaired. Further, in the field of packaging materials, particularly among the above, polyesters such as polyethylene teflate and olefin resins such as polyethylene and polypropylene are most preferably used.

Depending on the mode of use, even if a vapor deposition film of a metal oxide such as silicon oxide is provided on the surface of the second molded body 103 on the side of the first molded body 101 or the surface on the opposite side by vapor deposition or the like. good.

By the way, since the first molded product 101 is made of plastic, its oxygen permeability is higher than that of a metal material or the like. Therefore, the first molded product 101 has a barrier property against oxygen or the like. It is required to grant. In particular, since the second molded body 103 is merely overlapped on the first molded body 101 without being adhered to each other, the first molded body 101 and the second molded body 101 are as shown in FIG. A minute void CL may be formed between the molded body 103 and the molded body 103, and an air layer may be present along with the void CL. Therefore, it is required to suppress the oxygen permeation of the first molded product 101.

<Barrier coating 105>
In the present invention, the barrier coating 105 is provided in order to suppress the permeation of oxygen into the first molded product 101. That is, by providing such a barrier coating 105, oxygen permeating through the first plastic molded body 101 having a high oxygen permeability can be effectively suppressed.

In the present invention, as shown in FIG. 1, it is most preferable that the barrier coating 105 is provided on the surface of the first molded product 101 (the surface on the side of the second molded product 103). This makes it possible to effectively prevent the permeation of the air existing in the void CL through the first molded product 105. However, when the second molded body 103 is made of plastic or paper, the barrier coating 105 can be provided on the surface of the second molded body 103 (that is, the surface on the side of the first molded body 101). That is, this makes it possible to prevent the permeation of oxygen through the second molded body 103 and the void CL. Of course, the barrier coating is applied to both the surface of the first molded body 101 and the surface of the second molded body 103, provided that it exists between the first molded body 101 and the second molded body 103. 105 can also be provided.

In the present invention, the barrier coating 105 is formed by spray spraying, dipping, roll coating, or the like, but it is particularly important that the barrier coating 105 can be removed by washing with water. It is that.
That is, the waste of various plastic products is collected for each plastic forming this product, and is mechanically separated from other parts used together with the plastic and collected, whereby various plastics or various plastics or Other parts and the like can be reused, but when the plastic product has a multi-layer structure including a barrier material, the barrier material cannot be removed and it becomes difficult to reuse the plastic.
However, in the present invention, since the barrier coating 105 can be removed by washing with water, for example, it is heated to 90 ° C. specified in the voluntary design guideline for designated PET bottles published by the PET Bottle Recycling Promotion Council. Since it can be easily removed by immersing it in a 1.5% alkaline aqueous solution for 15 minutes, it effectively suppresses oxygen permeation of the first molded product and exists in the region covered by the first molded product. Not only can the oxidative deterioration of the substance be effectively prevented, but also the plastic material or the like forming the first molded body 101 or the second molded body 103 can be reused.

In the present invention, the barrier coating 105 that can be removed by washing with water as described above contains a water-soluble binder, and the water-soluble binder has a structure in which a functional material for enhancing oxygen blocking property is dispersed. Have.

Water-soluble binder;
As the water-soluble binder, various water-soluble materials can be used as long as they have a film-forming property and are water-soluble so that they can be removed by washing with water.
For example, specific examples thereof include, but are not limited to, water-soluble polymers such as polyvinyl alcohol polymers, polycarboxylic acid polymers, polyallylamine, and polyethyleneimine. Further, polysaccharides such as starch, carboxymethyl cellulose and sodium alginate or derivatives thereof can also be used as a water-soluble binder.
The polyvinyl alcohol polymer is obtained by polymerizing a vinyl ester compound and then saponifying it completely or partially. From the viewpoint of enabling removal by washing with water in the present invention, it is preferable to use an unmodified polyvinyl alcohol resin, but a partially modified modified polyvinyl alcohol resin may be used.
In addition, the polycarboxylic acid polymer includes homopolymers or copolymers of monomers having a carboxyl group such as polyacrylic acid, polymethacrylic acid, polymaleic acid, polyitaconic acid, and acrylic acid-methacrylic acid copolymers, and portions thereof. A neutralized product can be used, and preferably polyacrylic acid and polymethacrylic acid are used. Among these polymers, the polyvinyl alcohol polymer is most preferable from the viewpoint of easy availability, film forming property, and the like.

Functional material;
Functional materials for enhancing oxygen barrier properties include so-called passive barrier materials and active barrier materials.

As the passive barrier material, for example, a layered clay mineral such as montmorillonite or a so-called gas barrier resin can be used, but in particular, the layered clay mineral can be uniformly dispersed in the above-mentioned water-soluble binder, which is high. From the viewpoint of exhibiting oxygen barrier properties, it is preferably used in the present invention.

Further, the active barrier material is easily oxidized by reacting with oxygen, and various organic and inorganic materials are known. In particular, the active barrier material can be uniformly dispersed in the above-mentioned water-soluble binder. From the viewpoint of transparency, an organic oxidizable material is preferably used.

Examples of the organic oxidizable material include so-called oxygen absorbers or antioxidants such as ascorbic acid (vitamin C), tocopherol (vitamin E), dibutylhydroxytoluene, butylhydroxyanisole, sodium elsorbate, and propyl carouside. A compound known as, a polyene polymer having an aliphatic unsaturated bond such as polybutadiene or polyisoprene, and a compound having an unsaturated alicyclic structure are typical, and among them, an unsaturated alicyclic. Compounds having a structure are preferably used. Such an organic oxidizable material not only has high oxygen blocking property, but also has no problem of coloring, and can be suitably used for applications requiring transparency.
In a compound having an unsaturated alicyclic structure, when it comes into contact with oxygen, the unsaturated bond portion in the ring is easily oxidized, whereby oxygen is absorbed and oxygen absorption is exhibited. Unsaturated bonds present within the aromatic ring do not exhibit such oxidizability.

In the present invention, examples of the compound having an unsaturated alicyclic structure as described above (unsaturated alicyclic compound) include methyltetrahydroinden, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, and 5-isopropi. There are lidene-2-norbornene, 5-vinylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, dicyclopentadiene and the like. In the present invention, the following formula (1):

In the formula, ring X is an aliphatic ring having one unsaturated bond.
Y is an alkyl group,
At least one selected from the group consisting of an acid anhydride represented by, an ester derived from the acid anhydride, an amide, an imide or a dicarboxylic acid, and a polymer having a structural unit derived from the acid anhydride is the most. Suitable for use.

In the above formula (1), the aliphatic ring X is a 6-membered ring having one unsaturated bond, that is, a cyclohexene ring, and the position of the unsaturated bond may be either the 3-position or the 4-position. In particular, the 3-position is preferable from the viewpoint of oxidability. The alkyl group is not particularly limited, but generally, from the viewpoint of synthesis and oxidability, a lower alkyl group having 3 or less carbon atoms, particularly a methyl group is preferable, and the bonding position thereof is generally 3. It may be either the 4th place or the 4th place. Such an acid anhydride is alkyltetrahydrophthalic anhydride, which is obtained by the Diels-Alder reaction of maleic anhydride and diene, each obtained in the form of a mixture of isomers, and the mixture remains as a functional material. Can be used.
In the present invention, as the most preferable examples of the acid anhydride, 3-methyl -Δ represented by the following formula (2) ⁴ - represented by tetrahydrophthalic anhydride, and the following formula (3) 4- Methyl-Δ ³ -tetrahydrophthalic anhydride can be mentioned.

Further, the above-mentioned acid anhydride can form a derivative by a method known per se, but such a derivative can be used as the oxygen absorbing component (B) as long as the unsaturated alicyclic structure is maintained. can. That is, an ester, amide, imide, or dicarboxylic acid derived from the above acid anhydride can be used as an oxidizable functional material.

The above ester is an ester obtained by reacting an acid anhydride such as alkyltetrahydrophthalic anhydride with various alcohols, and the alcohol used for esterification is not particularly limited, and methyl alcohol, ethyl alcohol, propyl alcohol and the like are not particularly limited. Any of the aliphatic alcohols and aromatic alcohols such as phenol and benzyl alcohol can be used. Further, a polyhydric alcohol such as glycol can also be used. In this case, an unsaturated alicyclic structure corresponding to the number of alcohols in one molecule can be introduced.
Further, such an ester may be a partial ester of the acid anhydride.
That is, such an ester is represented by, for example, the following formula.
ROO-OC-Z-CO-OR
HOOC-Z-CO-OR
Alternatively, HOOC-Z-CO-O-R-O-CO-Z-COOH
In the formula, Z is an unsaturated alicyclic of the acid anhydride.
R is an organic group derived from the alcohol used in the reaction.

The above amide is obtained by reacting an acid anhydride such as alkyltetrahydrophthalic anhydride with various amine compounds.
The amine used is not particularly limited, and any of an aliphatic amine such as methylamine, ethylamine and propylamine and an aromatic amine such as phenylamine can be used, and two amines forming an acid anhydride group can be used. One of the carbonyl groups of the above may be amidated, or both may be amidated. Furthermore, the present invention is not limited to monoamines, and polyvalent amines such as diamines and triamines can also be used. In this case, an unsaturated alicyclic structure corresponding to the number of amines in one molecule can be introduced. can.

The imide is an imidized product obtained by heat-treating the above amide, and is, for example, the following formula;
HOOC-Z-CONH-R
Alternatively, HOOC-Z-CONH-R-CONH-Z-COOH
In the formula, Z is an unsaturated alicyclic of the acid anhydride.
R is an organic group derived from the amine used in the reaction.
It is obtained by heat-treating the amide represented by the following formula;
Z- (CO) ₂ -NR
Alternatively, Z- (CO) ₂ -N-RN- (CO) _2- Z
In the formula, Z and R are the same as above.
It is represented by.

Further, the dicarboxylic acid is obtained by hydrolyzing the acid anhydride and cleaving the acid anhydride group, and is represented by the following formula.
HOOC-Z-COOH
In the formula, Z and R are the same as above.

Furthermore, a polymer having a structural unit derived from the acid anhydride described above can also be used as a functional material to be blended in a water-soluble binder because it exhibits oxygen absorption. That is, the acid anhydride represented by the above-mentioned formula (1) can be used as a dibasic acid component forming a polyester. Such a copolymerized polyester has an unsaturated alicyclic structure in the molecular chain and therefore exhibits a predetermined oxygen absorption (oxidation property), and therefore is used as a functional material for imparting oxygen blocking property. It is possible to do so.

Further, in the present invention, among the acid anhydride represented by the above general formula or the compound derived from the acid anhydride, a non-polymer type compound having a molecular weight of 2000 or less, more preferably 1000 or less ( That is, a compound having no repeating unit in the molecule) is preferable. Since such low molecular weight non-polymeric compounds have high molecular mobility, they are particularly highly reactive with oxygen and highly compatible with water-soluble binders, so that they exhibit high oxygen absorption and transparency. Is. Among such low molecular weight non-polymeric compounds, the imide compound obtained by heat-treating the amide, which is a reaction product of the acid anhydride of the general formula (1) and an amine, has a particularly high oxygen absorption capacity. Is shown, and it is used more preferably.

As the amine used in the production of such an imide compound, either an aliphatic amine or an aromatic amine can be used.

Examples of the above aliphatic amines and aromatic amines include methylamine, methylenediamine, propylamine, propylenediamine, butylamine, butylenediamine, pentylamine, pentamethylenediamine, hexylamine, hexamethylenediamine, and heptylamine. Heptamethylenediamine, octylamine, octamethylenedimine, nonylamine, nonamethylenediamine, decylamine, decamethylenedimine, undecylamine, undecamethylenediamine, dodecylamine, dodecamethylenediamine, tridecylamine, tridecamethylenediamine, tetradecyl Amine, tetradecamethylenediamine, pentadecylamine, pentadecamethylenediamine, hexadecylamine, hexadecamethylenediamine, heptadecylamine, heptadecamethylenediamine, octadecylamine, octadecamethylenediamine, nonadecilamine, nonadecamethylenediamine, eiko Sylamine, 1,3-bis (aminomethyl) cyclohexane, tris (2-aminoethyl) amine, m-xylylene diamine, p-xylylene diamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4, Examples thereof include 4'-diaminodiphenyl ether, 2,4,6-triamino-1,3,5-triazine, 2,4,6-triaminopyrimidine and the like.

In the present invention, among the various functional materials described above, a compound having an aliphatic unsaturated bond or an unsaturated alicyclic structure is preferably used from the viewpoint of exhibiting particularly high oxygen blocking property, and particularly unsaturated fat. Compounds having a ring structure are most preferably used.

In the present invention, the above-mentioned functional material may be blended in the water-soluble binder in an amount such that sufficient oxygen absorption, that is, oxygen blocking property can be obtained, depending on the type thereof. Since the specific blending amount differs depending on the type, it cannot be unconditionally specified, but generally, the amount is 10 to 300 parts by mass, particularly 50 to 250 parts by mass per 100 parts by mass of the water-soluble binder. It is preferable that it is used. If this amount is too small, sufficient oxygen blocking property cannot be ensured, and if it is too large, the film forming property of the water-soluble binder is impaired, and it is difficult to form a coating 105 having a uniform thickness. There is a risk of becoming.

Further, when a compound having an aliphatic unsaturated bond or an unsaturated alicyclic structure is used as the above-mentioned functional material, it is used in order to promote the reaction between the unsaturated bond and oxygen (oxygen absorption). A transition metal catalyst known per se can also be dispersed in the barrier coating 105.
Such a transition metal catalyst can be used in a so-called catalytic amount, and is usually in the form of a low-valent inorganic salt, organic salt or complex salt of the transition metal in an amount of 1000 ppm or less in terms of the transition metal per the above compound. Can be used as appropriate.

In such a transition metal catalyst, as the transition metal, a Group VIII metal of the periodic table such as iron, cobalt and nickel is suitable, but other metals such as Group I metal such as copper and silver, tin, titanium and zirconium are used. It may be a Group IV metal, a Group V metal such as vanadium, a Group VI metal such as chromium, a Group VII metal such as manganese, or the like. Of these, cobalt is particularly suitable because it significantly promotes oxygen absorption (oxidation of oxidizing organic components).

Examples of the inorganic salt of the transition metal include halides such as chlorides, sulfur oxy salts such as sulfates, nitrogen oxyate salts such as nitrates, phosphor oxy salts such as phosphates, and silicates. ..

Examples of the organic salt of the transition metal include carboxylic acid salt, sulfonate, phosphonate, and the like, but in the present invention, the carboxylic acid salt is preferable. Specific examples thereof include acetic acid, propionic acid, isopropionic acid, butanoic acid, isobutanoic acid, pentanoic acid, hexanoic acid, heptanic acid, isoheptanic acid, octanoic acid, 2-ethylhexanoic acid, nonanoic acid, 3,5,5. -Trimethylhexanoic acid, decanoic acid, neodecanoic acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, araquinic acid, linder acid, tsuzuic acid, petroseric acid, oleic acid, linoleic acid, linolenic acid , Arachidonic acid, formic acid, oxalic acid, sulfamic acid, naphthenic acid and other transition metal salts.

Examples of the transition metal complex include a complex with β-diketone or β-keto acid ester.

By blending a colorant or an ultraviolet absorber into the barrier coating 105 used in the present invention, it is possible to impart a light-shielding property in addition to an oxygen barrier property. Known pigments and dyes can be used as the colorant.
Further, in addition to the colorant and the ultraviolet absorber, the barrier coating 105 includes a viscosity modifier, a defoaming agent, a filler, a heat-resistant stabilizer, a weather-resistant stabilizer, and an antioxidant, as long as the characteristics are not impaired. Known blending agents such as anti-aging agents, light stabilizers, antistatic agents, metal viscosities, waxes, modifying resins and rubbers can also be blended according to their own known formulations.

The thickness of the barrier coating 105 made of the water-soluble binder and the functional material as described above is set to a thickness that can secure the required oxygen blocking property according to the application of the double structure 100.

The barrier coating 105 is formed by, for example, adding the above-mentioned water-soluble binder, functional material, and appropriately used transition metal catalyst into a volatile solvent such as water or ethanol and mixing them to obtain the coating. The liquid can be easily applied by applying the liquid to the surface of the first molded body 101 (or the second molded body 103) which has been subjected to surface treatment or anchor coating to improve the coatability, if necessary, and dried. can.

<Preferable form of double structure 100>
The double structure 100 of the present invention in which the barrier coating 105 that can be removed by washing with water is provided between the first molded body 101 and the second molded body 103 can be applied to various forms. Although it can be formed, it is particularly preferably used as a double-structured container formed by biaxial stretch blow molding.

The form of such a double-structured container is shown in FIG. 2, for example.
In FIG. 2, the double-structured container to which the double-structured structure 100 of the present invention is applied is indicated by 10 as a whole, and the outer container 1 and the inner container 3 housed inside the outer container 1 A barrier coating 5 is provided between the inner surface of the outer container 1 and the outer surface of the inner container 3. That is, in this example, the outer container 1 corresponds to the second molded body 103, the inner container 3 corresponds to the first molded body 101, and the barrier coating 5 can be removed by washing with water.

In FIG. 2, the outer container 1 has a bottle shape and is formed of a neck portion 1a, a body portion 1b connected to the neck portion 1a, and a bottom portion 1c closing the lower end of the body portion 1b. The bottom portion 1c is a blow-stretched portion, and the neck portion 1a is a fixed portion that is not blow-stretched, and is not thinned by blow-stretching. Further, an air introduction port 7 is formed in the neck portion 1a, and a recessed squeeze region is formed in the central portion of the body portion 1b so as to be easy to squeeze.

Further, in the example of FIG. 2, a support ring 1d is formed on the outer surface of the neck portion 1a of the outer container 1.

On the other hand, the inner container 3 has a neck portion 3a which is a non-stretched portion and a body portion 3b which is blow-stretched to have a thin bag shape. , It is in close contact with the inner surfaces of the body 1b and the bottom 1c of the outer container 1.
In such an inner container 3, the neck portion 3a is fitted in the neck portion 1a of the outer container 1. In the example of FIG. 1, the upper portion of the neck portion 3a protrudes from the neck portion 1a of the outer container 1, and a screw 3c for fixing the cap with a screw is formed in the protruding portion, and further, the screw 3c A protrusion 3d serving as a stopper is formed in the lower portion so that the inner container 3 does not penetrate deeply into the outer container 1.
Of course, the form of the double-structured container 10 to which the present invention is applied is not limited to the form shown in FIG. 2, and for example, a protrusion 3d serving as a stopper is formed on the upper end of the neck portion 3a of the inner container 3. Only can be provided, and a screw for attaching the cap can be provided on the outer surface of the neck portion 1a of the outer container 1 (the upper portion of the support ring 1d).

In the present invention, the above-mentioned outer container 1 is formed of a blow-moldable thermoplastic resin, and such a thermoplastic resin is used for molding the second molded body 103 as described above. It can be formed of the resin to be used, for example, an olefin resin, a polyester resin, or the like, but is formed of a polyester resin, preferably PET, from the viewpoint of blow moldability, container strength, and transparency.

Further, the inner container 3 is formed of a blow-moldable thermoplastic resin like the outer container 1, and since it is particularly easy to set blow-stretching conditions, the thermoplastic resin for forming the inner container 3 and the outer container 1 are formed. It is preferable that the thermoplastic resin forming the above is of the same type.

In the double-structured container 10 to which the present invention is applied, as shown in FIG. 2, the space between the inner surface of the outer container 1 and the outer surface of the inner container 3 corresponds to the barrier coating 105 that can be washed and removed with water. There is a coating 5 to be used.
That is, the coating 5 effectively suppresses the permeation of oxygen into the inner container 3, effectively avoids oxidative deterioration of the contents contained in the inner container 3, and maintains the freshness for a long period of time. can. Moreover, since the coating 5 can be easily removed by washing with water, the outer container 1 and the inner container 3 can be separated by quickly removing the double-structured container 10 discarded after use by washing with water using a rare alkaline aqueous solution or the like. .. Therefore, it becomes easy to reuse the resin such as PET forming the inner container 3 (or the outer container 1).

The coating 5 corresponding to the barrier coating 105 may be provided on the inner surface of the outer container 1 or may be provided on the outer surface of the inner container 3, but since the bottle 10 does not adhere to both of them, A gap may be formed between the two and an air layer may exist. Therefore, it is preferable to provide the coating 5 on the outer surface of the inner container 3.

Since the above-mentioned double-structured container 10 is provided with the above-mentioned coating 5, it is manufactured by the so-called stack preform method.
That is, the first preform obtained by injection molding using the resin for the outer container 1 (preform for molding the outer container) and the first preform obtained by injection molding using the resin for the inner container 3. Using 2 preforms (preforms for forming inner containers), insert the 2nd preform into the 1st preform to form a multi-structured stack preform, and biaxially stretch the stack preform. It is manufactured by a method of blow molding.
That is, according to such a method, the coating 5 can be easily formed on the outer surface of the second preform (or the inner surface of the first preform).

In FIGS. 3 and 4 for explaining the above-mentioned stack preform method, the stack preform for forming a double-structured container of FIG. 2 is shown by 20 as a whole in FIG. 4, and is shown in FIG. As shown above, it is formed from a first preform 11 (see FIG. 3A) and a second preform 13 (see FIG. 3B), both of which have a test tube shape.
That is, the first preform 11 is a preform for molding the outer container, the second preform 13 is the preform for molding the inner container, and the second preform 13 is inserted into the first preform. By holding the fitting together, the stack preform 20 to be used in the blow stretching step is assembled.

As can be understood from FIG. 3, each of the first preform 11 and the second preform 13 has a portion corresponding to the neck portion 1a of the outer container 1 and the neck portion 3a of the inner container 3. That is, none of these portions are stretch-molded portions, and the first preform 11 has a support ring 1d and an air introduction port 7 formed by post-processing after injection molding, and a second preform 11. Preform 13 has a screw 3c and a protrusion 3d.
Further, the tubular portion 11b in which the lower end of the lower portion of the neck portion 1a of the first preform 11 is closed is stretch-molded, and by blow stretching, the body portion 1b and the bottom portion 1c of the outer container 1 are formed. It is shaped.
Further, the tubular portion 13b in which the lower end of the lower portion of the neck portion 3a of the second preform 13 is closed is stretch-molded, and is shaped into the form of the body portion 3b of the inner container 3 by blow stretching. NS. That is, a coating 5 (barrier coating 105) containing the above-mentioned water-soluble binder and functional material is usually formed on the portion to be the body portion 3 by stretch molding.

By inserting the second preform 13 into such a first preform 11, the stack preform 20 having the form shown in FIG. 4 is assembled, placed in a blow mold, and the neck portion is provided with a predetermined jig. The portion containing 1a and 3a is fixed (the region indicated by X in FIG. 4), and the stack preform 20 is stretch-moldable by high-frequency heating or the like (glass transition of the resin forming the preforms 11 and 13). Heat to a point temperature or higher and lower than the melting point), insert a stretch rod (not shown) into the stack preform 20 (second preform 13), stretch it in the uniaxial direction, and blow air or the like. By supplying the fluid and expanding it in the circumferential direction, the double-structured container 10 having the form shown in FIG. 2 can be obtained. That is, in FIG. 4, the region indicated by Y of the stack preform 20 is a portion to be stretch-molded.

In the present invention, by molding the double-structured container 10 by the method as described above, the coating 5 (barrier coating 105) containing the water-soluble binder and the functional material can be easily applied to the outer container 1 and the inner container 3. Can be formed between.
For example, in the method of molding a preform by co-injection molding and biaxially stretching blow molding this, in order to form a barrier layer between the outer container 1 and the inner container 3, a thermoplastic barrier resin is used. There is no choice but to use or use a thermoplastic resin in which a barrier material is dispersed. As already described, when the barrier property against oxygen is imparted by such a method, the barrier material cannot be removed from the bottle discarded after use, and the recyclability is impaired.
However, when the stacking method described above is adopted, the preform for the outer container 1 (first preform 11) and the preform for the inner container 3 (second preform 13) are separately molded. Therefore, the coating 5 can be easily formed in the predetermined portion between the preforms 11 and 13, and the coating 5 can be easily removed by washing with water, so that the recyclability is not impaired.

In the double-structured container 10 described above, as described above, the coating 5 (barrier coating 105) prepares a coating liquid using a volatile solvent such as water or ethanol, and uses this coating liquid. The coating 5 can be easily formed by applying it to the outer surface of the stretch-molded portion (cylindrical portion 13b) of the second preform by spraying or dipping, and then drying it. Usually, it is preferable to form the functional material in the coating 5 so as to be distributed in an amount of ^{1 g / m 2 or more.}
By blow-stretch molding the stack preform 20 provided with the coating 5 in this way, as shown in FIG. 2, the coating 5 that can be washed and removed between the outer container 1 and the inner container 3 can be removed. Can be provided.
At the time of such blow stretching molding, since the water-soluble binder (and the functional material) in the coating 5 is in a fluid state, the first preform 11 and the second preform do not cause film breakage or the like. The coating 5 can be provided in a predetermined area by being stretched together with the 13.

The double-structured container 10 manufactured as described above is an inner container by providing a path for introducing air between the inner surface of the outer container 1 and the outer surface of the inner container 3 in advance or by post-processing. After accommodating the contents in the body portion 3b of 3, the neck portion 1a of the outer container 1 can be used as an airless container by attaching a cap with a check valve known per se.

In the double-structured container 10 to which the present invention is applied, the contents filled in the inner bag 3 squeeze (press) the recessed portion (squeeze region) of the body portion 1b of the outer container 1, for example. By doing so, the contents are discharged by the amount pressed and dented, and the volume of the body 3b of the inner container 3 is reduced by that amount, but the body 3b and the outer container 1 are discharged from the air introduction port 7 by that amount. Since air is introduced into the inner surface of the body portion 1b to form an air layer, the subsequent contents can be effectively discharged.
In the present invention, the invasion of oxygen from the body 3b of the inner container 3 to the inside can be effectively suppressed and prevented by the coating 5, and the oxidative deterioration of the contents can be effectively prevented, but the bottle is discarded after use. Since the coating 5 from the above can be easily removed by washing with water, excellent recyclability is ensured.

The present invention will be further described by the following examples, but the present invention is not limited to these examples.
Next, the materials and test methods used in Examples and Comparative Examples are shown.

<Synthesis example of oxidizing organic components>
A 1000 mL 4-neck separable flask equipped with a stirrer, a nitrogen introduction tube, and a dropping funnel was charged with 250 g of a methyltetrahydrophthalic anhydride mixture (HN-2200: manufactured by Hitachi Kasei). The phthalic anhydride mixture, 4-methyl - [delta ³ - tetrahydrophthalic anhydride and 45% by weight and cis-3- methyl - [delta ⁴ - tetrahydro phthalic anhydride those which contain 21 wt%.
101 g of m-xylylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in 200 mL of ethanol was gradually added to a 4-neck separable flask containing this phthalic anhydride mixture. After the whole amount was added, the reaction was carried out at 120 ° C. to 180 ° C. under a nitrogen atmosphere for about 5 hours while removing the generated water to obtain an oxidizing organic component MXBI.

<Preparation of coating liquid>
(Coating liquid A)
Polyvinyl alcohol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd .: polyvinyl alcohol 1,000 completely saponified type) was prepared as a water-soluble binder.
The coating liquid A was obtained by adding 10 g of the above polyvinyl alcohol to 100 g of distilled water, heating to 95 ° C., and stirring until completely dissolved.

(Coating liquid B)
Coating liquid B was obtained by further adding 5 g of L (+)-ascorbic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as an oxidizing organic component to the coating liquid A and dissolving it.

(Coating liquid C)
Polyacrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd .: polyacrylic acid 250,000) was prepared as a water-soluble binder.
2 g of this polyacrylic acid was added to 100 g of ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to completely dissolve it, and then 5 g of MXBI as an oxidizing organic component was added and dissolved to obtain a coating liquid C.

(Coating liquid D)
A coating liquid D was obtained by adding 2.5 mg of N-hydroxyphthalimide (manufactured by Tokyo Chemical Industry Co., Ltd.) as an oxidation promoting component to the coating liquid C and dissolving it.

(Coating liquid E)
To the coating liquid C, 5.3 mg of cobalt stearate (manufactured by Wako Pure Chemical Industries, Ltd.) as a transition metal catalyst was added and dissolved to obtain a coating liquid E.

(Coating liquid F)
A coating liquid F was obtained in the same manner as the coating liquid C except that the amount of MXBI, which is an oxidizable organic component, was changed to 1 g.

(Coating liquid G)
A coating liquid G was obtained in the same manner as the coating liquid C except that the amount of MXBI, which is an oxidizable organic component, was changed to 2 g.

(Coating liquid H)
A coating liquid H was prepared by adding an edible pigment brown to the coating liquid A in which polyvinyl alcohol was used as the water-soluble binder.

(Coating liquid I)
A butanediol vinyl alcohol copolymer (manufactured by Mitsubishi Chemical Corporation: G polymer BVE8049Q) was prepared as a water-soluble binder.
20 g of this butanediol vinyl alcohol copolymer was added to 100 g of distilled water, heated to 95 ° C., and stirred until completely dissolved to prepare a coating liquid I.

(Coating liquid J)
A coating liquid J was prepared by adding 25 g of the above butanediol vinyl alcohol copolymer to 100 g of distilled water, heating to 95 ° C., and stirring until completely dissolved.

<Example 1>
Isophthalic acid copolymer polyethylene terephthalate resin (Shinko Synthetic Fiber 5015w, isophthalic acid copolymerization ratio = 1.8 mol%, intrinsic viscosity (IV) = 0.83) was used as a material for forming the preform for the inner container and the preform for the outer container. I prepared it.
By injection molding using this copolymerized polyethylene terephthalate resin, a preform for an inner container (12 g) and a preform for an outer container (17 g) were obtained.
After surface treatment of this inner container preform with oxygen plasma using a microwave plasma surface treatment device (Micro Labo-PS2: manufactured by Nissin Co., Ltd.), coating liquid A is applied to the outer surface by dipping and a dryer is used. After drying (the dry coating amount of the coating liquid A was 0.35 g), the preforms for the outer container were overlapped and biaxially stretched and blow-molded into a 500 mL bottle.

<Example 2>
A biaxially stretched blow bottle was obtained in the same manner as in Example 1 except that the coating liquid A was changed to the coating liquid B and the dry coating amount thereof was set to the amount shown in Table 1.

<Example 3>
A biaxially stretched blow bottle was obtained in the same manner as in Example 1 except that the coating liquid A was changed to the coating liquid C and the dry coating amount thereof was set to the amount shown in Table 1.

<Example 4>
A biaxially stretched blow bottle was obtained in the same manner as in Example 1 except that the coating liquid A was changed to the coating liquid D and the dry coating amount thereof was set to the amount shown in Table 1.

<Example 5>
A biaxially stretched blow bottle was obtained in the same manner as in Example 1 except that the coating liquid A was changed to the coating liquid E and the dry coating amount thereof was set to the amount shown in Table 1.

<Example 6>
A biaxially stretched blow bottle was obtained in the same manner as in Example 1 except that the coating liquid A was changed to the coating liquid F and the dry coating amount thereof was set to the amount shown in Table 1.

<Example 7>
A biaxially stretched blow bottle was obtained in the same manner as in Example 1 except that the coating liquid A was changed to the coating liquid G and the dry coating amount thereof was set to the amount shown in Table 1.

<Example 8>
A biaxially stretched blow bottle was obtained in the same manner as in Example 5 except that the dry coating amount of the coating liquid E was changed to the amount shown in Table 1.

<Comparative example 1>
A biaxially stretched blow bottle was obtained in the same manner as in Example 1 except that it was prepared without coating.

<Comparative example 2>
Using a twin-screw extruder (TEM-35B: manufactured by Toshiba Machine Co., Ltd.) with granulation equipment with a barrel set temperature of 260 to 280 ° C., the above-mentioned isophthalic acid copolymer polyethylene terephthalate resin was used with the oxidizing organic component MXBI. Was kneaded at 10% and extruded into strands to obtain oxygen-absorbing resin pellets. The oxidizing organic component MXBI was added from the opening in the middle of the extruder by a liquid feeder (Mono pump: manufactured by Hyojin Equipment).
Then
The copolymerized polyethylene terephthalate resin: 90 parts by weight The oxygen-absorbing resin pellet: 10 parts by weight Cobalt neodecanoate (manufactured by OMG): 0.015 parts by weight was dry-blended, and a 31 g single-layer preform was formed by injection molding. The obtained single-layer preform was biaxially stretched and blow-molded into a 500 mL bottle.

<Example 9>
A biaxially stretched blow bottle was obtained in the same manner as in Example 1 except that the coating liquid A was changed to the coating liquid H and the dry coating amount thereof was set to the amount shown in Table 1.

<Comparative example 3>
A single-layer preform was obtained by dry blending 3 parts by weight of a colored masterbatch for brown PET resin composed of red and green organic pigments with 100 parts by weight of the above-mentioned isophthalic acid copolymer polyethylene terephthalate resin. The preform was then biaxially stretched and blow molded into a 500 mL bottle.

The biaxially stretched blow bottles produced in the above Examples and Comparative Examples were evaluated for barrier property, recyclability or light shielding property by the following method, and the results are shown in Table 1 or the coating amount together with the type and coating amount of the coating liquid used. It is shown in Table 2.

(Evaluation of barrier performance / Measurement of dissolved oxygen concentration)
Anoxic water with an oxygen concentration of 0.1 ppm or less was prepared with an anoxic water maker (LOW DISSOLVED OXYGEN: manufactured by Miura Kogyo Co., Ltd.), and the bottle was filled with oxygen and sealed with a plastic cap. .. The dissolved oxygen concentration in the bottle after storage at 23 ° C. and 50% RH for 28 days was measured with a non-destructive high-sensitivity oxygen concentration meter (Oxy-4 Trace v3: manufactured by Pressens).
The smaller the value of the dissolved oxygen concentration, the better the oxygen barrier property.

(Evaluation of light blocking effect)
The molded bottle body wall was cut out, and the transmittance was measured by attaching an integrating sphere device attached to a spectrophotometer (UV-3100: manufactured by Shimadzu Corporation). The light-shielding property was evaluated from the average transmittance in the range of 380 nm to 780 nm.
The smaller the average transmittance, the better the light-shielding property.

(Evaluation of recyclability)
The body of the molded bottle was cut into 1 cm squares and immersed in a 1.5% aqueous sodium hydroxide solution heated to 90 ° C. After 15 minutes, take out and wash with tap water, then visually, surface measurement by ATR method using Fourier transform infrared spectrophotometer (FTS7000 SILIES: manufactured by VARIAN), spectrophotometer (UV-3100: manufactured by Shimadzu Corporation) ) Was attached to the integrating sphere device, and the transmittance was measured, and the recyclability was evaluated by the presence or absence of the barrier component.
〇: Excellent recyclability. (The barrier component has been removed.)
×: Poor recyclability. (The barrier component remains.)

<Example 10>
A biaxially stretched blow bottle was obtained in the same manner as in Example 1 except that the coating liquid A was changed to the coating liquid I and the dry coating amount thereof was set to the amount shown in Table 1.

<Example 11>
A preform (20 g) for an inner container was obtained by injection molding using the above-mentioned isophthalic acid copolymer polyethylene terephthalate resin.
This preform for the inner container is surface-treated with oxygen plasma using a microwave plasma surface treatment device (Micro Labo-PS2: manufactured by Nissin Co., Ltd.), and then the coating liquid A is applied to the outer surface by dipping and dried with a dryer. (The dry coating amount of the coating liquid A was 0.21 g). A double preform was obtained by injection molding the copolymerized polyethylene terephthalate resin on the outside of the inner container preform so as to cover this coating to form the outer container preform (10 g). The obtained double preform was biaxially stretched and blow molded into a 500 mL bottle. The thickness of the inner container at the bottle body was about 200 μm, and the thickness of the outer container was about 100 μm.

<Example 12>
A biaxially stretched blow bottle was obtained in the same manner as in Example 11 except that the dry coating amount of the coating liquid A was changed to the amount shown in Table 1.

<Example 13>
A biaxially stretched blow bottle was obtained in the same manner as in Example 11 except that the coating liquid A was changed to the coating liquid I and the dry coating amount thereof was set to the amount shown in Table 1.

<Example 14>
A biaxially stretched blow bottle was obtained in the same manner as in Example 13 except that the dry coating amount of the coating liquid I was changed to the amount shown in Table 1.

<Example 15>
A biaxially stretched blow bottle was obtained in the same manner as in Example 11 except that the coating liquid A was changed to the coating liquid J and the dry coating amount thereof was set to the amount shown in Table 1.

The biaxially stretched blow bottles produced in Examples 10 to 15 above were evaluated for their barrier properties and recyclability by the same method as in Example 1, and the results are shown in the table together with the type and coating amount of the coating liquid used. Shown in 3.

<Example 16>
A biaxially stretched blow bottle was obtained in the same manner as in Example 1 except that the dry coating amount of the coating liquid A was changed to the amount shown in Table 3. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 22 ° C. and 60% RH by adjusting the humidity to 0% RH by filling 5 g of calcium chloride.

<Example 17>
A biaxially stretched blow bottle was prepared in the same manner as in Example 16 except that the coating liquid A was changed to the coating liquid H and the dry coating amount was changed to the amount shown in Table 3, and the oxygen barrier was formed under the same conditions. evaluated.

<Example 18>
A biaxially stretched blow bottle was prepared in the same manner as in Example 16 except that the coating liquid A was changed to the coating liquid I and the dry coating amount was changed to the amount shown in Table 3, and the oxygen barrier was formed under the same conditions. evaluated.

<Example 19>
A biaxially stretched blow bottle was prepared in the same manner as in Example 16 except that the coating liquid A was changed to the coating liquid J and the dry coating amount was changed to the amount shown in Table 3, and the oxygen barrier was formed under the same conditions. evaluated.

<Comparative example 4>
A biaxially stretched blow bottle was prepared in the same manner as in Example 16 except that it was prepared without coating, and the oxygen barrier was evaluated under the same conditions.

<Example 20>
A biaxially stretched blow bottle was obtained in the same manner as in Example 16. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity to 0% RH by filling 5 g of calcium chloride.

<Example 21>
A biaxially stretched blow bottle was obtained in the same manner as in Example 17. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity to 0% RH by filling 5 g of calcium chloride.

<Example 22>
A biaxially stretched blow bottle was obtained in the same manner as in Example 18. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity to 0% RH by filling 5 g of calcium chloride.

<Example 23>
A biaxially stretched blow bottle was obtained in the same manner as in Example 19. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity to 0% RH by filling 5 g of calcium chloride.

<Comparative example 5>
A biaxially stretched blow bottle was obtained in the same manner as in Comparative Example 4. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity to 0% RH by filling 5 g of calcium chloride.

<Example 24>
A biaxially stretched blow bottle was obtained in the same manner as in Example 16. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 22 ° C. and 60% RH by adjusting the humidity of the inside to 70% RH by filling 5 ml of an aqueous glycerin solution.

<Example 25>
A biaxially stretched blow bottle was obtained in the same manner as in Example 18. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 22 ° C. and 60% RH by adjusting the humidity of the inside to 70% RH by filling 5 ml of an aqueous glycerin solution.

<Example 26>
A biaxially stretched blow bottle was obtained in the same manner as in Example 11 except that the dry coating amount of the coating liquid A was changed to the amount shown in Table 3. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 22 ° C. and 60% RH by adjusting the humidity of the inside to 70% RH by filling 5 ml of an aqueous glycerin solution.

<Example 27>
A biaxially stretched blow bottle was prepared in the same manner as in Example 26 except that the coating liquid A was changed to the coating liquid H and the dry coating amount was changed to the amount shown in Table 3, and the oxygen barrier was formed under the same conditions. evaluated.

<Example 28>
A biaxially stretched blow bottle was prepared in the same manner as in Example 26 except that the coating liquid A was changed to the coating liquid I and the dry coating amount was changed to the amount shown in Table 3, and the oxygen barrier was formed under the same conditions. evaluated.

<Example 29>
A biaxially stretched blow bottle was prepared in the same manner as in Example 26 except that the coating liquid A was changed to the coating liquid J and the dry coating amount was changed to the amount shown in Table 3, and the oxygen barrier was formed under the same conditions. evaluated.

<Comparative Example 6>
A biaxially stretched blow bottle was obtained in the same manner as in Comparative Example 4. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 22 ° C. and 60% RH by adjusting the humidity of the inside to 70% RH by filling 5 ml of an aqueous glycerin solution.

<Example 30>
A biaxially stretched blow bottle was obtained in the same manner as in Example 16. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity of the inside to 70% RH by filling 5 ml of an aqueous glycerin solution.

<Example 31>
A biaxially stretched blow bottle was obtained in the same manner as in Example 18. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity of the inside to 70% RH by filling 5 ml of an aqueous glycerin solution.

<Comparative Example 7>
A biaxially stretched blow bottle was obtained in the same manner as in Comparative Example 4. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity of the inside to 70% RH by filling 5 ml of an aqueous glycerin solution.

<Example 32>
A biaxially stretched blow bottle was obtained in the same manner as in Example 16. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 22 ° C. and 60% RH by adjusting the humidity to 100% RH by filling 5 ml of water.

<Example 33>
A biaxially stretched blow bottle was obtained in the same manner as in Example 18. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 22 ° C. and 60% RH by adjusting the humidity to 100% RH by filling 5 ml of water.

<Example 34>
A biaxially stretched blow bottle was obtained in the same manner as in Example 26. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 22 ° C. and 60% RH by adjusting the humidity to 100% RH by filling 5 ml of water.

<Example 35>
A biaxially stretched blow bottle was obtained in the same manner as in Example 28. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 22 ° C. and 60% RH by adjusting the humidity to 100% RH by filling 5 ml of water.

<Comparative Example 8>
A biaxially stretched blow bottle was obtained in the same manner as in Comparative Example 4. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 22 ° C. and 60% RH by adjusting the humidity to 100% RH by filling 5 ml of water.

<Example 36>
A biaxially stretched blow bottle was obtained in the same manner as in Example 16. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity to 100% RH by filling 5 ml of water.

<Example 37>
A biaxially stretched blow bottle was obtained in the same manner as in Example 18. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity to 100% RH by filling 5 ml of water.

<Example 38>
A biaxially stretched blow bottle was obtained in the same manner as in Example 26. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity to 100% RH by filling 5 ml of water.

<Example 39>
A biaxially stretched blow bottle was obtained in the same manner as in Example 28. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity to 100% RH by filling 5 ml of water.

<Comparative Example 9>
A biaxially stretched blow bottle was obtained in the same manner as in Comparative Example 4. The evaluation of the oxygen barrier of the obtained bottle was carried out in a storage environment of 30 ° C. and 80% RH by adjusting the humidity to 100% RH by filling 5 ml of water.

For the bottles prepared in Examples 16 to 39 and Comparative Examples 4 to 9 above, the barrier property was evaluated by measuring the oxygen concentration in the bottle by the following method, and the result was used as the type of coating liquid. , And the coating amount are shown in Table 4.

(Evaluation of barrier performance / Measurement of oxygen concentration in bottle)
The molded bottle was sealed with an aluminum foil laminated film in a nitrogen-substituted glove box. At this time, the humidity was adjusted so that the inside of the bottle had 0% RH, 70% RH, or 100% RH. After storage in an environment of 22 ° C. 60% RH or 30 ° C. 80% RH and stored for 28 days, the oxygen concentration in the bottle was measured with a non-destructive high-sensitivity oxygen concentration meter (Oxy-4 Trace v3: manufactured by Pressens).
The smaller the value of this oxygen concentration, the better the oxygen barrier performance.

100: Double structure 101: First molded body 103: Second molded body 105: Barrier coating 1: Outer container 3: Inner container 5: Coating (barrier coating 105)
7: Air inlet 10: Double-structured container 11: First preform 13: Second preform

Claims (13)

1. In a double structure composed of a first molded body and a second molded body superposed on the first molded body,
   A double structure characterized in that at least the first molded body is made of plastic and a barrier coating that can be washed and removed is present between the first molded body and the second molded body.
2. The double structure according to claim 1, wherein the barrier coating is provided on the side of the first molded body.
3. The double structure according to claim 1, wherein the barrier coating is provided on the side of the second molded body.
4. The double structure according to claim 1, wherein the barrier coating contains a water-soluble binder.
5. The double structure according to claim 4, wherein the barrier coating has a structure in which a functional material for enhancing the oxygen blocking property of the water-soluble binder is dispersed in the water-soluble binder.
6. The double structure according to claim 5, wherein the functional material is an oxidizable organic compound.
7. The oxidizing organic compound has the following formula (1):
   

   

   In the formula, ring X is an aliphatic ring having one unsaturated bond.
   Y is an alkyl group,
   A claim which is at least one selected from the group consisting of an acid anhydride represented by, an ester derived from the acid anhydride, an amide, an imide or a dicarboxylic acid, and a polymer having a structural unit derived from the acid anhydride. Item 6. The double structure according to Item 6.
8. The double structure according to claim 4, wherein the water-soluble binder is a polyvinyl alcohol polymer or a polycarboxylic acid polymer.
9. Claim 1 in which the first molded body is an inner container, the second molded body is an outer container containing the inner container, and the barrier coating is provided on the outer surface of the inner container. The double structure described in.
10. The first molded body is a preform for an inner container, the second molded body is a preform for an outer container containing the preform for the inner container, and the barrier is placed on the outer surface of the preform for the inner container. The double structure according to claim 1, which is provided with a coating and has a stack preform structure.
11. A composition for forming a barrier coating containing an oxidizable organic compound and a water-soluble binder.
12. The composition for forming a barrier coating according to claim 11, which contains the oxidizing organic compound in the range of 10 to 300 parts by mass per 100 parts by mass of the water-soluble binder.
13. The resin composition for forming a barrier coating according to claim 11, wherein the water-soluble binder is a polyvinyl alcohol polymer or a polycarboxylic acid polymer.

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