JP2020082730A - Double structure body - Google Patents

Abstract

To provide a double structure body which is used in a state of laminating two compacts, can efficiently suppress oxygen transmission by a barrier material, can easily remove a barrier material and can efficiently reuse a material such as resin forming each compact.SOLUTION: In a double structure body 100 formed of a first compact 101 and a second compact 103 laminated on the first compact, at least the first compact 101 is made of plastic, and between the first and second compacts 101, 103, a barrier coating 105 which can be removed by washing, is provided.SELECTED DRAWING: Figure 1

Description

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 molded into various shapes. However, plastic products are inferior in gas barrier property to metal products and glass products.
For this reason, passive plastic materials such as ethylene/vinyl alcohol copolymer resins are used for applications that require barrier properties against oxygen, such as plastic products used as packaging materials for containers and films. A multilayer structure using the above layers has been introduced.
On the other hand, recently, an active barrier material such as an oxidizable organic compound has also been developed (see, for example, Patent Document 1) and has been used in the field of packaging materials and the like.
Further, it may be used by imparting a light-shielding property by coloring the light barrier for the purpose.

However, a packaging material having a gas barrier property enhanced by the above-mentioned barrier material and a colored resin have a drawback in that they are difficult to recycle and difficult to reuse.
That is, in a multi-layered container 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 and polyolefin), and the same colorant is used. Can not be separated from the container material resin, making it difficult to reuse these material resins. Barrier technology considering the reusability of the material resin has hardly been studied.

For example, recently, a double structure container having a double structure including an inner container and an outer container has been put into practical use as an airless container in which 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 squeezed from the outside to dent the wall of the body of the bottle, which is an outer container, to fill the inner container. When the contents are discharged from the pouring passage formed in the cap and the discharge of the contents is ended by stopping the pressing of the body wall of the bottle, 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 of the discharged contents, and the inner container shrinks each time the contents are discharged. In a double-structured container whose contents are discharged by such a method, the contents can be dispensed and air can effectively be prevented from entering the inner container filled with the contents. There is an advantage that deterioration can be effectively avoided and the freshness of the contents can be maintained for a long time.

Even in the double-structured container as described above, 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, in Patent Document 2, when a preform for an inner container and a preform for an outer container are stacked and stretch-molded to manufacture a container having a double structure, a preform for an inner container and a preform for an 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 and a deodorant, is provided between the reform and the reform.
However, in such a technique, the powdery drug is merely filled in the space between the inner container and the outer container, and thus the adhesiveness between the drug and the inner container or the outer container is insufficient. Further, such a powdered drug has not been put into practical use because it inhibits the reusability of the resin for the container material.

JP, 2018-21128, A JP-A-5-228988

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

According to the invention,
In a double structure comprising a first molded body and a second molded body superposed on the first molded body,
At least the first molded body is made of plastic, and a water-removable barrier coating is present between the first molded body and the second molded body. To 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 barrier property of the water-soluble binder is dispersed in the water-soluble binder.
(5) The functional material is an oxidizable organic compound.
(6) The oxidizable 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,
At least one selected from the group consisting of an acid anhydride represented by, an ester, an amide, an imide or a dicarboxylic acid derived from the acid anhydride, and a polymer having a structural unit derived from the acid anhydride. ..
(7) The water-soluble binder is a polyvinyl alcohol-based polymer or a polycarboxylic acid-based polymer.
(8) The first molded body is an inner container, the second molded body is an outer container accommodating 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 outer surface of the preform for the inner container is The barrier coating is provided and has a stack preform structure.

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

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 with respect to 100 parts by mass of the water-soluble binder,
(11) The water-soluble binder is a polyvinyl alcohol-based polymer or a polycarboxylic acid-based polymer,
Is preferred.

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

INDUSTRIAL APPLICABILITY The double structure of the present invention can be effectively applied to a double structure container manufactured by a stack preform method. The stack preform obtained by inserting and holding the inside of the preform for blow molding is stretch blow molded to obtain a double-structured container having a barrier coating between the inner container and the outer container. 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, in such a double-structured container, the barrier coating can be easily removed by washing with water in the recycling process, and the container is separated into the inner container and the outer container. Therefore, this double structure container is excellent in recyclability since 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. 3 is a schematic side sectional view immediately after molding of a double structure container which is a preferred example of the double structure of the present invention. FIG. 3 is a schematic side sectional view showing formation of 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. 2. FIG. 3 is a schematic side sectional view showing a stack preform in which a second preform is housed and held in the first preform.

Referring to FIG. 1, the double structure 100 of the present invention is formed by stacking a second molded body 103 on a first molded body 101. Has a barrier coating 105 formed on the surface thereof. That is, the second molded body 103 is overlaid 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 application. For example, when the first molded body 101 made of plastic is used for applications such as packaging, it may have a form such as a film or a sheet depending on the form of the substance to be packaged, and It may have such a form. Furthermore, the second molded body 103 is used so as to cover the first molded body 101 without being adhered, and is simply used by being stacked, and is used, for example, for simple packaging. The material is not particularly limited, and may be paper, metal foil, or the like, but in general, depending on the form of the first formed body 101, it can be easily formed into a form that covers it, Like the first molded body 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 which can be removed by washing with water as described above is provided between the first molded body 101 and the second molded body 103. By subjecting the molded body of (1) to means such as vacuum molding, pressure molding, bulging molding, and plug assist molding, a cup-shaped or tray-shaped container can be obtained.

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 resins.
Olefinic resin 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. -1-Pentene or random or block copolymers of α-olefins such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, and cyclic olefin copolymers;
Ethylene/vinyl copolymers, for example, ethylene/vinyl acetate copolymers, ethylene/vinyl alcohol copolymers, ethylene/vinyl chloride copolymers, ion-crosslinked olefin copolymers (ionomers), etc.;
Styrenic resins such as polystyrene, acrylonitrile/styrene copolymer, ABS, α-methylstyrene/styrene copolymer, etc.;
Vinyl resins such as polyvinyl chloride, polyvinylidene chloride, vinyl chloride/vinylidene chloride copolymers, polymethyl acrylate, 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;
Polycarbonate resin;
Polyphenylene oxide resin;
Biodegradable resins such as polylactic acid (PLA), polybutylene succinate (PBS), polyhydroxyalkanoate (PHA) and copolymers thereof;
Of course, blends of these thermoplastic resins can also be used as long as the moldability is not impaired. In the field of packaging materials, polyesters such as polyethylene terephthalate and olefin resins such as polyethylene and polypropylene are most preferably used among the above.

Depending on the usage pattern, a vapor deposition film of a metal oxide such as silicon oxide may be provided by vapor deposition or the like on the surface of the second compact 103 on the first compact 101 side or on the opposite surface. Good.

By the way, since the first molded body 101 is made of plastic and its oxygen permeability is higher than that of a metal material or the like, the first molded body 101 has a barrier property against oxygen and the like. It is required to give. In particular, since the second molded body 103 is simply overlaid on the first molded body 101 without being bonded, as shown in FIG. 1, the first molded body 101 and the second molded body 101 are not overlapped. A minute void CL may be formed between the molded body 103 and an air layer may be present along with the void CL. Therefore, it is necessary to suppress the oxygen permeation of the first molded body 101.

<Barrier coating 105>
In the present invention, the barrier coating 105 is provided in order to suppress oxygen permeation into the first molded body 101. That is, by providing such a barrier coating 105, it is possible to effectively suppress oxygen that permeates the plastic first molded body 101 having high oxygen permeability.

In the present invention, as shown in FIG. 1, the barrier coating 105 is most preferably provided on the surface of the first molded body 101 (the surface on the side of the second molded body 103). Therefore, it is possible to effectively prevent the air existing in the gap CL from permeating the first molded body 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 first molded body 101 side). That is, this makes it possible to prevent the permeation of oxygen through the second molded body 103 and the void CL. Of course, 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 application of spray spraying, dipping, roll coating, etc., but particularly importantly, the barrier coating 105 can be removed by washing with water. It has become.
That is, the wastes of various plastic products are collected for each plastic forming the product, mechanically separated from other parts used together with the plastics, and collected. Although other parts can be reused, if the plastic product has a multi-layer structure including a barrier material, the barrier material cannot be removed, which makes reuse of the plastic difficult.
However, in the present invention, since the barrier coating 105 can be removed by washing with water, for example, the barrier coating 105 was heated to 90° C. indicated in the voluntary design guideline of the designated PET bottle announced 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 body and exists in the region covered by the first molded body. Not only can the oxidation deterioration of the substance be effectively prevented, but also the plastic material or the like forming the first molded body 101 and 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 the oxygen barrier property is dispersed. Have

Water-soluble binder;
As the water-soluble binder, various water-soluble materials can be used as long as they have film-forming properties and water-solubility that can be removed by washing with water.
For example, specific examples thereof include, but are not limited to, polyvinyl alcohol-based polymers, polycarboxylic acid-based polymers, polymers such as polyallylamine and polyethyleneimine, and starch, carboxymethyl cellulose, sodium alginate, and the like. A polysaccharide or its derivative can be mentioned.
The polyvinyl alcohol-based 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.
Further, the polycarboxylic acid-based polymer, polyacrylic acid, polymethacrylic acid, polymaleic acid, polyitaconic acid, homopolymer or copolymer of monomers having a carboxyl group such as acrylic acid-methacrylic acid copolymer, and these A partially neutralized product can be used, and it is preferable to use polyacrylic acid or polymethacrylic acid. Among these polymers, polyvinyl alcohol-based polymers are most preferable from the viewpoints of easy availability, film-forming property, and the like.

Functional materials;
Functional materials for enhancing the oxygen barrier property 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 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 one that is easily oxidized by reacting with oxygen, and various organic and inorganic materials are known, but in particular, it can be uniformly dispersed in the water-soluble binder described above, From the viewpoint of transparency, an organic oxidizable material is preferably used.

Examples of organic oxidizable materials include so-called oxygen absorbers or antioxidants such as ascorbic acid (vitamin C), tocopherol (vitamin E), dibutylhydroxytoluene, butylhydroxyanisole, sodium ersorbate, and propyl gallate. Compounds known as, polyene polymers having an aliphatic unsaturated bond such as polybutadiene and polyisoprene, further, compounds having an unsaturated alicyclic structure are typical, among them, unsaturated alicyclic A compound having a structure is preferably used. Such an organic oxidizable material not only has a high oxygen barrier property but also has no coloring problem and can be suitably used for applications requiring transparency.
Incidentally, the compound having an unsaturated alicyclic structure, when it comes into contact with oxygen, the portion of the unsaturated bond in the ring is easily oxidized, thereby, oxygen is absorbed, oxygen absorption is exhibited, The unsaturated bond existing in the aromatic ring does not show such oxidizability.

In the present invention, as the compound having an unsaturated alicyclic structure as described above (unsaturated alicyclic structure compound), methyltetrahydroindene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylamine Although there are lidene-2-norbornene, 5-vinylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, dicyclopentadiene, etc., in the present invention, particularly 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, an amide, an imide or a dicarboxylic acid derived from the acid anhydride, and a polymer having a structural unit derived from the acid anhydride is most It is preferably used.

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 third position is preferable from the viewpoint of oxidizability. The alkyl group is not particularly limited, but generally, from the viewpoint of synthesis and oxidizability, 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 or 4th place. Such an acid anhydride is an alkyltetrahydrophthalic anhydride, which is obtained by the Diels-Alder reaction of maleic anhydride and a diene, and is obtained in the form of a mixture of isomers, respectively, and the mixture as it is is used as a functional material. Can be used.
In the present invention, the most preferable examples of the acid anhydride are 3-methyl-Δ ⁴ -tetrahydrophthalic anhydride represented by the following formula (2) and 4- represented by the following formula (3). Mention may be made of methyl-Δ ³ -tetrahydrophthalic anhydride.

Further, the above-mentioned acid anhydride can form a derivative by a method known per se, but as long as the unsaturated alicyclic structure is maintained, such a derivative can be used as the oxygen absorbing component (B). it 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-mentioned 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, etc. Any of the above aliphatic alcohols and aromatic alcohols such as phenol and benzyl alcohol can be used. Furthermore, polyhydric alcohols such as glycol can also be used. In this case, the number of unsaturated alicyclic structures corresponding to the number of alcohols in one molecule can be introduced.
Further, the ester may be a partial ester of the acid anhydride.
That is, such an ester is represented by the following formula, for example.
R-O-OC-Z-CO-O-R
HOOC-Z-CO-OR
Or
HOOC-Z-CO-O-R-O-CO-Z-COOH
In the formula, Z is an unsaturated alicyclic ring which the acid anhydride has,
R is an organic group derived from the alcohol used in the reaction.

Further, the 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 aliphatic amines such as methylamine, ethylamine and propylamine, and aromatic amines such as phenylamine can be used, and two amines forming an acid anhydride group can be used. One of the carbonyl groups may be amidated, or both of them may be amidated. Furthermore, not only monoamines but also polyamines such as diamines and triamines can be used. In this case, it is possible to introduce a number of unsaturated alicyclic structures corresponding to the number of amines in one molecule. it can.

Further, the imide is obtained by heat-treating the above amide, and has, 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 ring which the acid anhydride has,
R is an organic group derived from the amine used in the reaction,
Obtained by heat-treating an amide represented by the following formula:
Z-(CO) ₂ -NR
Alternatively, Z-(CO) ₂ -NR-N-(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 an 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.

Further, the above-mentioned polymer having a structural unit derived from an acid anhydride also exhibits oxygen absorbability, and thus can be used as a functional material to be blended in a water-soluble binder. That is, the acid anhydride represented by the above formula (1) can be used as a dibasic acid component forming a polyester. Since such a copolyester has an unsaturated alicyclic structure in the molecular chain and therefore exhibits a predetermined oxygen absorption (oxidizable) property, it is used as a functional material that imparts oxygen barrier properties. It becomes possible to do it.

Further, in the present invention, among the acid anhydrides represented by the above-mentioned general formulas, or compounds derived from the acid anhydrides, a non-polymeric compound having a molecular weight of 2000 or less, more preferably 1000 or less, is particularly preferable. That is, a compound having no repeating unit in the molecule) is suitable. Since such a low molecular weight non-polymer type compound has high molecular mobility, it has high reactivity with oxygen, and also has high compatibility with a water-soluble binder, and thus exhibits high oxygen absorption and transparency. Is. Among such low molecular weight non-polymeric compounds, the imide compound obtained by heat-treating an amide, which is a reaction product of the acid anhydride of the general formula (1) and an amine, has a particularly high oxygen absorption ability. And is more preferably used.

As the amine used for producing such an imide compound, both an aliphatic amine and an aromatic amine can be used.

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

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 a particularly high oxygen-blocking property, and particularly an unsaturated fat The compound having a ring structure is 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 barrier property can be obtained depending on the type. The specific blending amount cannot be unconditionally specified because it varies depending on the type, but in general, it 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 preferably used. If this amount is too small, sufficient oxygen barrier property cannot be secured, and if it is too large, the film forming property of the water-soluble binder is impaired, and it is difficult to form the coating 105 with a uniform thickness. May be

In addition, when a compound having an aliphatic unsaturated bond or an unsaturated alicyclic structure is used as the above-mentioned functional material, in order to promote the reaction between the unsaturated bond and oxygen (oxygen absorbability), A transition metal catalyst known per se can 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 an inorganic salt, an organic salt or a complex salt having a low valence 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, the transition metal is preferably a Group VIII metal of the Periodic Table such as iron, cobalt and nickel, but other Group I metals such as copper and silver, tin, titanium and zirconium. 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, and the like. Among these, cobalt is particularly preferable because it remarkably promotes oxygen absorption (oxidation of oxidizing organic components).

Examples of the inorganic salts of transition metals include halides such as chlorides, sulfur oxy salts such as sulfates, nitrogen oxy acid salts such as nitrates, phosphorus oxy salts such as phosphates, and silicates. ..

Examples of the organic salt of the transition metal include carboxylates, sulfonates, phosphonates and the like. In the present invention, carboxylates are preferable. Specific examples thereof include acetic acid, propionic acid, isopropionic acid, butanoic acid, isobutanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, isoheptanoic 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, arachidic acid, linderic acid, tsuzuic acid, petroselinic acid, oleic acid, linoleic acid, linolenic acid , Transition metal salts such as arachidonic acid, formic acid, oxalic acid, sulfamic acid, and naphthenic acid.

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

The barrier coating 105 used in the present invention may have a light shielding property in addition to an oxygen barrier property by blending a colorant or an ultraviolet absorber. Known pigments and dyes can be used as the colorant.
In addition to the colorant and the ultraviolet absorber, the barrier coating 105 contains a viscosity modifier, an antifoaming agent, a filler, a heat resistance stabilizer, a weather resistance stabilizer, an antioxidant, in addition to the colorant and the ultraviolet light absorber. Known compounding agents such as an antiaging agent, a light stabilizer, an antistatic agent, a metal soap, a wax, a modifying resin or a rubber can be compounded according to a known method.

The thickness of the barrier coating 105 composed of the water-soluble binder and the functional material as described above is set so as to ensure the required oxygen barrier property depending on 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 transition metal catalyst used appropriately into a volatile solvent such as water or ethanol and mixing them to obtain a 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) that has been subjected to a surface treatment or anchor coating to enhance the coating property as necessary and dried. it 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 described above is provided between the first molded body 101 and the second molded body 103 can be applied to various forms. However, it is particularly suitable for use as a double-structured container formed by biaxial stretch blow molding.

The form of such a double-structured container is shown, for example, in FIG.
In FIG. 2, the double structure container to which the double structure 100 of the present invention is applied is indicated by 10 as a whole, and includes an outer container 1 and an inner container 3 housed inside the outer container 1. The 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 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, and the body portion 1b and the bottom portion 1c are blow-stretched. The neck portion 1a is a fixed portion that is not blow-stretched and is not thinned by blow stretching. An air inlet 7 is formed in the neck portion 1a, and a recessed squeeze region is formed in the center portion of the body portion 1b to facilitate squeezing.

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 that is a non-stretched portion and a body portion 3b that is blow-stretched to have a thin bag shape. At the stage immediately after molding, the outer surface of the body portion 3b is , And is closely attached to the inner surfaces of the body portion 1b and the bottom portion 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, and in the example of FIG. 1, the upper portion of the neck portion 3a projects from the neck portion 1a of the outer container 1, A screw 3c for screw-fixing the cap is formed on the projecting portion, and a projection 3d serving as a stopper is provided at a lower portion of the screw 3c so that the inner container 3 does not deeply enter the outer container 1. Are formed.
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, the protrusion 3d serving as a stopper is provided at the upper end of the neck portion 3a of the inner container 3. It is also possible to provide only a screw and to provide a screw for mounting the cap 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 outer container 1 described above 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. Although it can be formed of a resin such as an olefin resin or a polyester resin, it is formed of a polyester resin, most preferably PET, from the viewpoint of blow moldability, container strength, and transparency.

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

In the double-structured container 10 to which the present invention is applied, as shown in FIG. 2, between the inner surface of the outer container 1 and the outer surface of the inner container 3, the barrier coating 105 that can be washed with water is removed. Coating 5 is present.
That is, the coating 5 effectively suppresses the permeation of oxygen into the inner container 3, effectively avoids the oxidative deterioration of the contents contained in the inner container 3, and maintains the freshness thereof for a long period of time. it 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 diluted alkaline aqueous solution or the like. .. Therefore, the resin such as PET forming the inner container 3 (or the outer container 1) can be easily reused.

The coating 5 corresponding to the above 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 both to each other, A void may be formed between them and an air layer may exist. Therefore, it is preferable to provide the coating 5 on the outer surface of the inner container 3.

The double-structured container 10 described above is manufactured by the so-called stack preform method because the coating 5 as described above is provided.
That is, the first preform obtained by injection molding using the resin for the outer container 1 (preform for molding outer container) and the first preform obtained by injection molding using the resin for the inner container 3 The second preform (preform for forming an inner container) is used, the second preform is inserted into the first preform to form a stack preform having a multiple structure, and the stack preform is biaxially stretched. It is manufactured by a method of performing 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).

3 and 4 for explaining the stack preform method described above, the stack preform for molding the double-structured container of FIG. 2 is designated as a whole by 20 in FIG. 4 and is shown in FIG. As described above, the first preform 11 (see FIG. 3A) and the second preform 13 (see FIG. 3B) each having a test tube shape are formed.
That is, the first preform 11 is a preform for molding an outer container, the second preform 13 is a preform for molding an inner container, and the second preform 13 is inserted into the first preform. By fitting and holding the stack preforms 20, the stack preforms 20 used in the blow stretching process are assembled.

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

By assembling the stack preform 20 shown in FIG. 4 by inserting the second preform 13 into the first preform 11 as described above, the stack preform 20 is placed in the blow mold, and the neck portion is fixed with a predetermined jig. A portion including 1a and 3a is fixed (a region indicated by X in FIG. 4), and the stack preform 20 can be stretch-molded at a temperature (glass transition of the resin forming the preforms 11 and 13) by high frequency heating or the like. The stack preform 20 (second preform 13) is heated to a temperature higher than the point temperature and lower than the melting point), a stretch rod (not shown) is inserted into the stack preform 20 and stretched uniaxially, and further blown with 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 is obtained. That is, in FIG. 4, a 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 formed on 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 stretch blow molding the same, 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 take the means of using or using a thermoplastic resin in which a barrier material is dispersed. As described above, when the barrier property against oxygen is imparted by such a method, the barrier material cannot be removed from the discarded bottle 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 molded separately. Therefore, the coating 5 can be easily formed on a predetermined portion between the preforms 11 and 13, and the coating 5 can be easily removed by washing with water, so that recyclability is not impaired.

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

The double-structured container 10 manufactured as described above is provided with 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, thereby providing an inner container. After storing the contents in the body portion 3b of 3, the outer container 1 can be used as an airless container by attaching a known check valve cap to the neck 1a of the outer container 1.

In the double-structured container 10 to which the present invention is applied, the content filled in the inner bag 3 is squeezed (pressed) on 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 being pressed and dented one by one, and the body portion 3b of the inner container 3 is reduced in volume, but the body portion 3b and the outer container 1 of the inner container 3 are reduced by that amount. Since air is introduced between the inner surface of the body portion 1b and the air layer, an air layer is formed, so that the subsequent discharge of the contents is also effectively performed.
In such a bottle, the invasion of oxygen into the inside from the body portion 3b of the inner container 3 can be effectively suppressed and prevented by the coating 5, and the oxidative deterioration of the contents can be effectively prevented. Since the coating 5 can be easily removed by washing with water, excellent recyclability is secured.

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

<Synthesis example of oxidizable organic component>
A 1000 mL 4-neck separable flask equipped with a stirrer, a nitrogen introducing tube, and a dropping funnel was charged with 45% by weight of 4-methyl-Δ ³ -tetrahydrophthalic anhydride and cis-3-methyl-Δ ⁴ -tetrahydrophthalic anhydride. Was added, and 250 g of a methyltetrahydrophthalic anhydride mixture (HN-2200: manufactured by Hitachi Chemical) containing 21% by weight of was added. To this, 101 g of an amine component dissolved in 200 mL of ethanol; metaxylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was gradually added. After the total amount was charged, the oxidizable organic component MXBI was obtained by reacting in a nitrogen atmosphere at 120° C. to 180° C. for about 5 hours while removing generated water.

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

(Coating liquid B)
As a water-soluble binder, 10 g of polyvinyl alcohol (manufactured by FUJIFILM Wako Pure Chemical Industries: 1,000 fully saponified polyvinyl alcohol) was added to 100 g of distilled water, heated to 95° C. and stirred until completely dissolved, and further as an oxidizable organic component. A coating liquid B was prepared by adding and dissolving 5 g of L(+)-ascorbic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

(Coating liquid C)
As a water-soluble binder, 2 g of polyacrylic acid (manufactured by FUJIFILM Wako Pure Chemical Co., Ltd.: 250,000 polyacrylic acid) was added to 100 g of ethanol (manufactured by FUJIFILM Wako Pure Chemical Industries) and completely dissolved, and further 5 g of MXBI was added as an oxidizable organic component. A coating liquid C was obtained by dissolving.

(Coating liquid D)
2 g of polyacrylic acid (manufactured by FUJIFILM Wako Pure Chemical Industries: 250,000 polyacrylic acid) as a water-soluble binder was added to 100 g of ethanol (manufactured by FUJIFILM Wako Pure Chemical Industries) to completely dissolve it, and 5 g of MXBI as an oxidizable organic component, Coating solution D was obtained by adding 2.5 mg of N-hydroxyphthalimide (manufactured by Tokyo Chemical Industry Co., Ltd.) as an oxidation promoting component and dissolving it.

(Coating liquid E)
2 g of polyacrylic acid (manufactured by FUJIFILM Wako Pure Chemical Industries: 250,000 polyacrylic acid) as a water-soluble binder was added to 100 g of ethanol (manufactured by FUJIFILM Wako Pure Chemical Industries) to completely dissolve it, and 5 g of MXBI as an oxidizable organic component, Coating liquid E was obtained by adding 5.3 mg of cobalt stearate (manufactured by Wako Pure Chemical Industries, Ltd.) as a transition metal catalyst and dissolving it.

(Coating liquid F)
As a water-soluble binder, 2 g of polyacrylic acid (manufactured by FUJIFILM Wako Pure Chemical Co., Ltd.: 250,000 polyacrylic acid) was added to 100 g of ethanol (manufactured by FUJIFILM Wako Pure Chemical Industries) and completely dissolved, and 1 g of MXBI was added as an oxidizable organic component. A coating liquid F was obtained by dissolving.

(Coating liquid G)
As a water-soluble binder, 2 g of polyacrylic acid (manufactured by FUJIFILM Wako Pure Chemical Co., Ltd.: 250,000 polyacrylic acid) was added to 100 g of ethanol (manufactured by FUJIFILM Wako Pure Chemical Industries) and completely dissolved, and 2 g of MXBI was further added as an oxidizable organic component. A coating liquid G was obtained by dissolving.

(Coating liquid H)
As a water-soluble binder, 10 g of polyvinyl alcohol (manufactured by FUJIFILM Wako Pure Chemical Industries: 1,000 fully saponified polyvinyl alcohol) is added to 100 g of distilled water and heated to 95° C. to completely dissolve it. Liquid H was prepared.

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

(Coating liquid J)
Coating liquid J was prepared by adding 25 g of butanediol vinyl alcohol copolymer (manufactured by Mitsubishi Chemical: G polymer BVE8049Q) as a water-soluble binder to 100 g of distilled water, heating to 95° C., and stirring until completely dissolved.

<Example 1>
Isophthalic acid (copolymerization ratio = 1.8 mol%) Copolyethylene terephthalate resin (5015w: Shinko Synthetic Fiber, IV = 0.83) was used to inject the inner container preform (12 g) and outer container preform (17 g), respectively. Obtained by molding. This inner container preform is subjected to a surface treatment by 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 0.35 g), and the preform for the outer container was overlapped and biaxially stretch blow molded into a bottle for 500 mL.

<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 was changed 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 was changed 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 was changed 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 was changed 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 was changed 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 was changed 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 the bottle was prepared without coating.

<Comparative example 2>
Using a twin-screw extruder (TEM-35B: manufactured by Toshiba Machine Co., Ltd.) with a granulation facility having a barrel set temperature of 260 to 280°C, isophthalic acid (copolymerization ratio = 1.8 mol%) copolymerized polyethylene terephthalate resin (5015w: manufactured by Shinko Synthetic Fiber, IV=0.83) was mixed and kneaded with an oxidizable organic component MXBI at 10% and extruded in a strand form to obtain an oxygen-absorbing resin pellet. The oxidizable organic component MXBI was added from an opening in the middle of the extruder by a liquid feeder (Mono pump: made by Hyojin equipment). 90 parts by weight of isophthalic acid (copolymerization ratio=1.8 mol %) copolymerized polyethylene terephthalate resin (5015w: made by Shinko Synthetic Fiber, IV=0.83), 10 parts by weight of oxygen-absorbing resin pellets, cobalt neodecanoate (made by OMG) Dry blending 0.015 parts by weight and molding a 31 g single layer preform by injection molding. Next, the molded preform was biaxially stretch 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 was changed to the amount shown in Table 1.

<Comparative example 3>
Colored masterbatch for brown PET resin consisting of red and green organic pigments in 100 parts by weight of isophthalic acid (copolymerization ratio=1.8 mol%) copolymerized polyethylene terephthalate resin (5015w: Shinko Synthetic Fiber, IV=0.83) Was dry-blended to obtain a single-layer preform by injection molding. Next, the molded preform was biaxially stretch blow molded into a 500 mL bottle.

With respect to the biaxially stretched blow bottles produced in the above Examples and Comparative Examples, the barrier property, the recyclability or the light shielding property was evaluated by the following methods, and the results are shown in Table 1 together with the type of the coating liquid used and the coating amount. The results are shown in Table 2.

(Evaluation of barrier performance/Measurement of dissolved oxygen concentration)
Oxygen-free water having an oxygen concentration of 0.1 ppm or less was prepared with an oxygen-free water generator (LOW DISSOLVED OXYGEN: manufactured by Miura Industry Co., Ltd.), and the bottle was filled with the oxygen-free water and sealed with a plastic cap. .. The dissolved oxygen concentration in water in the bottle after storing at 23° C. and 50% RH for 28 days was measured by a nondestructive 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.

(Shading evaluation)
The molded bottle barrel wall was cut out, and a spectrophotometer (UV-3100: manufactured by Shimadzu Corporation) was equipped with an integrating sphere device attached thereto to measure the transmittance. 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 square pieces and immersed in a 1.5% aqueous sodium hydroxide solution heated to 90°C. After 15 minutes, after taking out and washing with tap water, the surface was measured by the ATR method using a Fourier transform infrared spectrophotometer (FTS 7000 SIREES: manufactured by VARIAN), and a spectrophotometer (UV-3100: manufactured by Shimadzu Corporation). ) Was attached to the integrating sphere device, and the transmittance was measured to evaluate the recyclability by the presence or absence of the barrier component.
◯: Excellent recyclability. (The barrier component has been removed.)
X: Recyclability is poor. (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 was changed to the amount shown in Table 1.

<Example 11>
A preform (20 g) for an inner container was obtained by injection molding from isophthalic acid (copolymerization ratio=1.8 mol %) copolymerized polyethylene terephthalate resin (5015w: manufactured by Shinko Synthetic Fiber, IV=0.83). This inner container preform is subjected to a surface treatment by 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 coating amount of the coating liquid A was 0.21 g). An outer container preform (10 g) was molded by injection molding on the outside of the inner container preform so as to cover the coating, and the obtained preform was biaxially stretch blow molded into a 500 mL bottle. The thickness of the inner container in 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 was changed 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 was changed to the amount shown in Table 1.

With respect to the biaxially stretched blow bottles produced in the above Examples 10 to 15, the barrier property and the recyclability were evaluated in the same manner as in Example 1, and the results are shown together with the type of coating liquid used and the coating amount. 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 performed in a storage environment of 22° C. and 60% RH with 5 g of calcium chloride being filled to adjust the inside humidity to 0% RH.

<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 an oxygen barrier was provided 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 an oxygen barrier was provided 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 an oxygen barrier was provided 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 with 5 g of calcium chloride filled to adjust the inside humidity to 0% RH.

<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 with 5 g of calcium chloride filled to adjust the inside humidity to 0% RH.

<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 with 5 g of calcium chloride filled to adjust the inside humidity to 0% RH.

<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 with 5 g of calcium chloride filled to adjust the inside humidity to 0% RH.

<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 with 5 g of calcium chloride filled to adjust the inside humidity to 0% RH.

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

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

<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 oxygen barrier of the obtained bottle was evaluated in a storage environment of 22° C. and 60% RH by filling 5 ml of an aqueous solution of glycerin to adjust the inside humidity to 70% RH.

<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 an oxygen barrier was provided 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 an oxygen barrier was provided 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 an oxygen barrier was provided 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 oxygen barrier of the obtained bottle was evaluated in a storage environment of 22° C. and 60% RH by filling 5 ml of an aqueous solution of glycerin to adjust the inside humidity to 70% RH.

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

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

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

<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 performed in a storage environment of 22° C. and 60% RH with 5 ml of water filled to adjust the inside humidity to 100% RH.

<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 performed in a storage environment of 22° C. and 60% RH with 5 ml of water filled to adjust the inside humidity to 100% RH.

<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 performed in a storage environment of 22° C. and 60% RH with 5 ml of water filled to adjust the inside humidity to 100% RH.

<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 performed in a storage environment of 22° C. and 60% RH with 5 ml of water filled to adjust the inside humidity to 100% RH.

<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 performed in a storage environment of 22° C. and 60% RH with 5 ml of water filled to adjust the inside humidity to 100% RH.

<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 performed in a storage environment of 30° C. and 80% RH by filling 5 ml of water to adjust the inside humidity to 100% RH.

<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 performed in a storage environment of 30° C. and 80% RH by filling 5 ml of water to adjust the inside humidity to 100% RH.

<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 performed in a storage environment of 30° C. and 80% RH by filling 5 ml of water to adjust the inside humidity to 100% RH.

<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 performed in a storage environment of 30° C. and 80% RH by filling 5 ml of water to adjust the inside humidity to 100% RH.

<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 performed in a storage environment of 30° C. and 80% RH by filling 5 ml of water to adjust the inside humidity to 100% RH.

With respect to 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 to determine the type of coating liquid used. The coating amount is 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 inside the bottle was adjusted to 0% RH, 70% RH or 100% RH. The oxygen concentration in the bottle after storing in an environment of 22° C. 60% RH or 30° C. 80% RH and storing for 28 days was measured with a nondestructive 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 structure container 11: 1st preform 13: 2nd preform

Claims (13)

In a double structure comprising a first molded body and a second molded body superposed on the first molded body,
At least the first molded body is made of plastic, and a water-removable barrier coating is present between the first molded body and the second molded body. The double structure according to claim 1, wherein the barrier coating is provided on the first molded body side. The double structure according to claim 1, wherein the barrier coating is provided on the side of the second molded body. The double structure according to claim 1, wherein the barrier coating contains a water-soluble binder. The double structure according to claim 4, wherein the barrier coating has a structure in which a functional material for enhancing the oxygen barrier property of the water-soluble binder is dispersed in the water-soluble binder. The double structure according to claim 5, wherein the functional material is an oxidizable organic compound. The oxidizable 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,
Is at least one selected from the group consisting of an acid anhydride represented by, an ester, an amide, an imide or a dicarboxylic acid derived from the acid anhydride, and a polymer having a structural unit derived from the acid anhydride. Item 7. The double structure according to item 6. The double structure according to any one of claims 4 to 7, wherein the water-soluble binder is a polyvinyl alcohol-based polymer or a polycarboxylic acid-based polymer. The first molded body is an inner container, the second molded body is an outer container accommodating the inner container, and the barrier coating is provided on an outer surface of the inner container. The double structure according to any one of to 8. The first molded body is an inner container preform, the second molded body is an outer container preform accommodating the inner container preform, and the barrier is provided on the outer surface of the inner container preform. The double structure according to any one of claims 1 to 8, which is provided with a coating and has a stack preform structure. A composition for forming a barrier coating, comprising an oxidizable organic compound and a water-soluble binder. A composition for forming a barrier coating, containing the oxidizable organic compound in an amount of 10 to 300 parts by mass based on 100 parts by mass of the water-soluble binder. The resin composition for forming a barrier coating according to claim 11 or 12, wherein the water-soluble binder is a polyvinyl alcohol-based polymer or a polycarboxylic acid-based polymer.