JP7187970B2 - Stretch molded structure with barrier coating - Google Patents

Description

The present invention relates to stretch formed structures with barrier coatings.

In recent years, plastics have been used in various applications because they can be easily molded into various shapes. However, plastic products are inferior in gas barrier properties to metal products and glass products.
For this reason, passive barrier 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 such as containers and films. A multi-layer structure using layers of
On the other hand, recently, active barrier materials such as oxidizable organic compounds have also been developed (see, for example, Patent Documents 1 and 2), and have come to be used in fields such as packaging materials.

By the way, conventionally known active barrier materials do not have the same formability as various thermoplastic resins used for packaging materials and the like, so they are used in the form of a resin composition blended with a base thermoplastic resin. By being present as an intermediate layer in various resin moldings, a barrier property against oxygen has been exhibited.

JP-A-5-115776 WO2013/099921

However, conventionally known forms of use of the active barrier material require melt-kneading with other resin components. However, it is in a state of being deteriorated due to heat history due to melt-kneading, and it is difficult to say that its performance is fully exhibited.

Accordingly, an object of the present invention is to provide an active barrier material, that is, an oxidizable organic compound that exhibits oxygen scavenging properties by reacting with oxygen, and is used without undergoing melt-kneading or melt-molding to exhibit oxygen-blocking properties. It is to provide a structure that is

According to the present invention, there is provided a stretch-molded structure comprising a stretch-molded substrate and a barrier coating formed on the stretch-molded substrate surface and containing an oxidizable organic compound having stretch-following properties ,
A stretch-formed structure is provided, wherein the barrier coating is a non-binder coating containing 75% by mass or more of the oxidizable organic compound .

式中、環Ｘは、１つの不飽和結合を有する脂肪族環であり、
Ｙは、アルキル基である、
で表わされる酸無水物、該酸無水物から誘導されるエステル、アミド、イミド又はジカルボン酸、及び該酸無水物に由来する構成単位を有する重合体からなる群より選択された少なくとも一種であること。
（７）前記バリアコーティングが、遷移金属触媒フリーのコーティングであること。
（８）前記延伸成形基体が、エチレンテレフタレート系ポリエステルより形成されていること。 The stretch-formed structure of the present invention can preferably employ the following aspects.
(1) The barrier coating is a non-binder type coating containing 90% by mass or more of the oxidizable organic compound.
(2) It has a double structure in which a cover molded body is superimposed on the barrier coating of the stretch-molded substrate.
(3) The cover molded body is a stretched molded body.
(4) The oxidizable organic compound exhibits fluidity at a stretching temperature.
(5) The oxidizable organic compound has a viscosity of 1 to 30000 mPa·s at 100°C.
(6) The oxidizable organic compound has the following formula (1):

wherein 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, amide, imide or dicarboxylic acid derived from the acid anhydride, and a polymer having a structural unit derived from the acid anhydride .
(7) The barrier coating is a transition metal catalyst-free coating.
(8) The stretch-molded substrate is made of ethylene terephthalate-based polyester.

According to the present invention, there is also provided a double structure stretch molding preform comprising a first stretch molding preform and a second stretch molding preform superimposed on the first stretch molding preform. in
a stretch-following barrier coating comprising an oxidizable organic component is present between the first stretch-molding preform and the second stretch-molding preform ;
A preform for stretch molding with a dual structure is provided , wherein the barrier coating is a non-binder coating containing 75% by mass or more of the oxidizable organic compound .

The stretch-formed structure of the present invention is characterized in that a barrier coating in which an oxidizable organic compound (i.e., active barrier material) is stretched by stretching is provided on the surface of the stretch-formed substrate. have.
That is, in such a stretch-molded structure, the oxidizable organic compound is formed by coating (coating) without undergoing melt-kneading or melt-molding with other resins, so deterioration due to melt-kneading or melt-molding is prevented. is effectively avoided, and the oxygen barrier function by the oxygen absorption is maximized.

In addition, the oxidizable organic compound forming the barrier coating has stretch conformability and fluidity at the stretch forming temperature. Therefore, it can be applied to the surface of a preform for forming a stretch-molded substrate. For this reason, when the preform is stretch-molded, the surface of the resulting stretch-molded substrate may have cracks or the like in the barrier coating of the oxidizable organic compound, which is thinly stretched to follow the stretching and has a uniform thickness. The barrier function of the oxidizable organic compound can be effectively exhibited.

Furthermore, this barrier coating is, for example, a non-binder type coating containing 75% by mass or more of the oxidizable organic compound, and is substantially a layer formed of the oxidizable organic compound itself. Therefore, compared with conventional barrier layers formed of resin compositions in which an oxidizable compound is dispersed, the present invention exhibits significantly higher oxygen barrier properties, which is also a great advantage of the present invention.

The stretch-molded structure of the present invention is a dual-structure molded body obtained by laminating a cover molded body on the barrier coating in order to efficiently perform the oxygen-blocking function of the barrier coating of the oxidizable organic compound. It is suitable to use as.
That is, in a form in which the barrier coating of the oxidizable organic compound is directly exposed to the atmosphere, the oxygen absorption capacity of the oxidizable organic compound is exhausted in a short period of time. In this way, it is possible to effectively reduce the consumption of the oxygen absorption capacity of the oxidizable organic compound.

In the present invention, since the oxidizable organic compound has stretch-following properties, it is possible to use a stretch-molded body as the cover-molded body, and simultaneously perform stretch-molding to obtain the stretch-molded substrate and the cover-molded body. can. That is, a barrier coating is formed on the surface of a preform (first preform) for forming a stretch-molded substrate, and a preform (second preform) for forming a cover molding is formed so as to cover the barrier coating. Preforms) are stacked to form a stack preform, and this stack preform is stretch-molded, whereby a stretch-molded structure having a double structure can be obtained by one stretch-molding. Such a double structure container effectively prevents permeation of oxygen into the inner container, and can more effectively maintain the freshness of the contents contained in the inner container.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic sectional drawing for demonstrating the structure of the stretch molded object of this invention. Schematic cross-sectional view for explaining a double structure which is a preferred form of the stretched molded article of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side cross-sectional view immediately after molding of a double-structured container to which a double-structured body, which is a preferred example of the stretch-molded article of the present invention, is applied. FIG. 4 is a schematic side cross-sectional view showing a first preform (inner container molding preform) and a second preform (outer container molding preform) used for manufacturing the double structure container of FIG. 3 ; 1 is a schematic cross-sectional side view showing a stacked preform with a first preform contained and held within a second preform; FIG.

Referring to FIG. 1, the stretch-formed structure 100 of the present invention has a stretch-formed substrate 101 and a barrier coating 103 formed on the surface of the stretch-formed substrate.

The stretch-molded substrate 101 may have any shape according to the application as long as it is stretch-molded.
Such a stretch-formed structure 100 also typically has a cover-form 105 overlaid over the barrier coating 103 formed on the stretch-formed substrate 101, as shown in FIG. available in the form of

<Stretch-molded substrate 101>
The first stretch molded body 101, which is the base of the barrier coating 103, may have an appropriate shape according to its use. For example, when the stretched structure 100 is used for packaging purposes, it may be in the form of a film or sheet, or in the form of a container, depending on the form of the substance to be packaged. can be anything.

The stretch molded body 101 is made of various thermoplastic resins that can be stretch molded, and specific examples thereof include the following.
Olefinic 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 -1-pentene or random or block copolymers of α-olefins such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, cyclic olefin copolymers;
Ethylene-vinyl copolymers such as ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ethylene-vinyl chloride copolymers, ionically crosslinked olefin copolymers (ionomers), etc.;
Styrenic resins such as polystyrene, acrylonitrile/styrene copolymers, ABS, α-methylstyrene/styrene copolymers;
Vinyl resins such as polyvinyl chloride, polyvinylidene chloride, vinyl chloride/vinylidene chloride copolymers, polymethyl acrylate, polymethyl methacrylate, and the like;
polyamide resins, such as nylon 6, nylon 6-6, nylon 6-10, nylon 11, nylon 12;
Polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene furanoate (PEF), polytrimethylene furanoate (PTF) and copolymer 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 moldability is not compromised.
In the field of packaging materials, among the above, polyesters such as polyethylene terephthalate and olefin resins such as polyethylene and polypropylene are particularly suitable. Ethylene terephthalate-based polyesters are most preferably used.

By subjecting the molded body of the thermoplastic resin to stretch molding, oriented crystallization occurs and the stretch molded substrate 101 having improved properties such as heat resistance is obtained. by means of That is, depending on the desired shape, the resin may be stretched uniaxially or biaxially by blow stretching, vacuum molding (plug assist molding), etc. at a molding temperature above the glass transition point and below the melting point of the resin. Thus, a stretch-molded substrate 101 having a sheet-like, bottle-like, cup-like, or other shape is obtained.
The draw ratio and the like are appropriately set according to the application.

<Barrier coating 103>
In the present invention, a barrier coating 103 is provided in order to suppress oxygen permeation of the stretch-molded substrate 101, and the barrier coating 103 is formed by coating an oxidizable organic compound. In other words, when the oxidizable organic compound reacts with oxygen and is oxidized, the permeation of oxygen is blocked, and the material functions as a so-called active barrier material.

Such oxidizable organic compounds are known per se, and include various compounds having unsaturated aliphatic bonds, such as polyene polymers having aliphatic unsaturated bonds such as polybutadiene and polyisoprene, oleic acid, ( meth) unsaturated fatty acids such as acrylic acid; Representative examples are esters, amides, amines, imides, and mixtures thereof. Among these, in the present invention, those having stretch-following properties, specifically, compounds exhibiting fluidity during stretch molding is used. That is, by using such an oxidizable organic compound having stretch-followability, the barrier coating 103 is formed on a preform for forming the stretch-molded substrate 101, and stretch-molding is performed in this state. Thus, a stretch-molded substrate 101 (stretch-molded structure 100) having a barrier coating 103 on its surface can be obtained without causing cracks, peeling, or the like, and without impairing the properties of the stretch-molded body 101.

For example, with an oxidizable organic compound that does not have stretch followability, cracks and film peeling occur during stretch molding, so that the oxygen absorption by the oxidizable organic compound cannot be sufficiently exhibited. Therefore, the barrier coating 103 is formed by applying an oxidizable organic compound directly or using an organic solvent or the like to the surface of the stretch-molded substrate 101 already produced by stretch-molding. Also, due to heat from drying, contact with an organic solvent, and the like, shrinkage due to stretching may occur, and properties such as shape and rigidity may be impaired. However, the barrier coating 103 can be formed on the preform, plate, or sheet for molding the stretch-molded substrate 101 prior to stretching by using an oxidizable organic compound having stretching followability. , the above inconveniences can be effectively avoided.

Moreover, as understood from the above description, having stretch followability means having moderate fluidity at the stretch molding temperature. For example, ethylene terephthalate-based polyester is generally stretch-molded at a temperature of about 90 to 120°C, so the oxidizable organic compound to be used should have a viscosity in the range of 1 to 30000 mPa s at 100°C. is preferably used. In other words, a compound having a viscosity higher than the above range is unsatisfactory in stretch followability, and tends to cause cracks, film peeling, and the like during stretch molding.

式中、環Ｘは、１つの不飽和結合を有する脂肪族環であり、
Ｙは、アルキル基である、
で表わされる酸無水物、該酸無水物から誘導されるエステル、アミド、イミド又はジカルボン酸、及び該酸無水物に由来する構成単位を有する重合体からなる群より選択された少なくとも一種の中から、上記のような粘度を有するものを使用することが好ましい。このような化合物は、酸素との反応により臭い等の原因となるアルデヒドやケトン等の低分子化合物が生成しないという利点がある。 In the present invention, the barrier coating 103 is formed using an oxidizable organic compound known as an active barrier material that exhibits the viscosity described above. :

wherein 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, amide, imide or dicarboxylic acid derived from the acid anhydride, and a polymer having a structural unit derived from the acid anhydride , it is preferable to use one having a viscosity as described above. Such compounds have the advantage of not producing low-molecular-weight compounds such as aldehydes and ketones that cause odors when reacted with oxygen.

In the above formula (1), the aliphatic ring X is a 6-membered ring having one unsaturated bond, i.e., 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 oxidizability. In addition, although the alkyl group is not particularly limited, in general, from the viewpoint of synthesis and oxidizability, a lower alkyl group having 3 or less carbon atoms, particularly a methyl group, is preferable. It can be either 1st or 4th. Such an acid anhydride is an alkyltetrahydrophthalic anhydride, which is obtained by Diels-Alder reaction between maleic anhydride and a diene, is obtained in the form of a mixture of isomers, and the mixture 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- Mention may be made of methyl-Δ ³ -tetrahydrophthalic anhydride.

In addition, the above acid anhydride can form a derivative by a method known per se, and such a derivative can be used as the oxygen-absorbing component (B) as long as the unsaturated alicyclic structure is maintained. can. That is, esters, amides, imides, or dicarboxylic acids derived from the above acid anhydrides can be used as oxidizable functional materials.

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, etc. and aromatic alcohols such as phenol and benzyl alcohol can be used. Polyhydric alcohols such as glycols 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.
Such esters may also be partial esters of the above acid anhydrides.
That is, such esters are represented, for example, by the following formulae.
RO-OC-Z-CO-OR
HOOC-Z-CO-OR
or HOOC-Z-CO-OR-O-CO-Z-COOH
In the formula, Z is an unsaturated alicyclic ring possessed by the acid anhydride,
R is an organic group derived from the alcohol used in the reaction.

The above amides are obtained by reacting acid anhydrides such as alkyltetrahydrophthalic anhydride with various amine compounds.
The amine to be 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. One of the carbonyl groups of may be amidated, or both may be amidated. Furthermore, it is not limited to monoamines, and polyvalent amines such as diamines and triamines can also be used. In this case, the number of unsaturated alicyclic structures corresponding to the number of amines in one molecule can be introduced. can.

Further, the imide is imidized by heat-treating the above amide, for example, the following formula;
HOOC-Z-CONH-R
or HOOC-Z-CONH-R-CONH-Z-COOH
In the formula, Z is an unsaturated alicyclic ring possessed by the acid anhydride,
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 —N—R
or Z—(CO) ₂ —N—R—N—(CO) ₂ —Z
wherein Z and R are the same as above;
is represented by

Furthermore, the dicarboxylic acid is obtained by hydrolysis of an acid anhydride to cleave 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, since the polymer having structural units derived from the acid anhydride described above also exhibits oxygen absorbability, it can be used as long as the viscosity is within the range described above. That is, the acid anhydride represented by formula (1) described above can be used as a dibasic acid component for forming a polyester. Such a copolyester has an unsaturated alicyclic structure in the molecular chain, and therefore exhibits a certain degree of oxygen absorption (oxidability). It becomes possible to do so.

In addition, in the present invention, among the acid anhydrides represented by the above general formula or compounds derived from the acid anhydrides, particularly non-polymer type compounds having a molecular weight of 2000 or less, more preferably 1000 or less ( That is, many of the compounds having no repeating unit in the molecule have a viscosity within the above-mentioned range, and moreover, the molecular mobility is high, so the reactivity with oxygen is particularly high, and the oxygen absorbability is high. It is suitable for showing
Furthermore, among such low-molecular weight non-polymer type compounds, an imide compound obtained by heat-treating an amide, which is a reaction product of an acid anhydride of the general formula (1) and an amine, has particularly high oxygen absorption capacity. indicates

Both aliphatic amines and aromatic amines can be used as the amines used in the production of such imide compounds.

Examples of the above aliphatic amines and aromatic amines 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, Eiko silamine, 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 particular, in the present invention, meta-xylylene bisimide (at 100° C. of 1347 mPa·s), and hexamethylene bisimide (viscosity at 100° C.: 97.5 mPa·s) is most preferably used.

Furthermore, the barrier coating 103 made of the oxidizable organic compound described above is particularly of a non-binder type, does not use a binder resin, and is formed by coating the oxidizable organic compound itself. That is, since the barrier coating 103 is not formed by melt-kneading with a high-melting-point material such as resin or by melt-molding such as extrusion molding or injection molding, deterioration of the oxidizable organic compound can be effectively avoided. It has the great advantage of being

In addition, since the barrier coating 103 is substantially composed mainly of an oxidizable organic compound, it has an extremely high oxygen barrier compared to a barrier layer formed from a resin composition blended with a thermoplastic resin such as polyester. show gender. That is, it can be said that the barrier coating 103 itself is formed from an oxidizable organic compound.

Furthermore, in the present invention, the barrier coating 103 contains an oxidizable organic compound in an amount of, for example, 75% by mass or more, particularly 90% by mass or more, within a range that does not impair its properties. Various ingredients may be added as long as they are included.

A transition metal catalyst is representative of such a compounding agent. A transition metal catalyst can increase the reactivity with oxygen with a very small amount of so-called catalyst amount (for example, 1000 ppm or less in terms of transition metal per oxidizable organic compound). It can be present in coating 103 .
However, the above-described barrier coating 103 is formed almost entirely of the oxidizable organic compound itself, and exhibits high oxygen absorbability by itself. Therefore, considering cost reduction, etc., it can be made free of transition metal catalysts. preferred.

Such transition metal catalysts are used in the form of low valence inorganic salts, organic salts or complex salts of transition metals.
In such a transition metal catalyst, transition metals such as iron, cobalt, nickel and the like are suitable as the transition metals, but other metals such as group I metals such as copper and silver, tin, titanium, zirconium and the like are also suitable. It may be a Group IV metal, a Group V metal such as vanadium, a Group VI metal such as chromium, or a Group VII metal such as manganese. Among these, cobalt is particularly suitable because it remarkably promotes oxygen absorbability (oxidation of oxidizable organic components).

Examples of the inorganic salt of the transition metal include halides such as chlorides, sulfur oxysalts such as sulfates, nitrogen oxysalts such as nitrates, phosphorus oxysalts such as phosphates, and silicates. .

Organic salts of transition metals include carboxylates, sulfonates, phosphonates and the like, and carboxylates are preferred in the present invention. 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, lindelic acid, tuzunic acid, petroselinic acid, oleic acid, linoleic acid, linolenic acid , arachidonic acid, formic acid, oxalic acid, sulfamic acid, naphthenic acid and the like.

Complexes of transition metals include complexes with β-diketones or β-keto acid esters.

In addition to the above transition metal catalysts, a viscosity modifier or the like may be added, for example, in order to enhance the stretch conformability of the oxidizable organic compound. agents, fillers, colorants, heat stabilizers, weather stabilizers, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, antistatic agents, metal soaps, waxes, modifying resins or rubbers, etc. Known compounding agents can be compounded according to formulations known per se.

In the present invention, the above-described barrier coating 103 is formed by, for example, dissolving or dispersing the oxidizable organic compound in a coating liquid obtained by heating the oxidizable organic compound to impart appropriate fluidity or in a volatile organic solvent such as ethanol. The coating liquid prepared by the method is sprayed, dipped, roll-coated, or the like, and the surface of the stretch-molded substrate 101 or the stretch-molded substrate 101 subjected to a surface treatment or an anchor coat for improving the coatability as necessary. It is formed by applying it to the surface of the preform to be obtained and drying it as appropriate.
Also, as mentioned above, the barrier coating 103 is applied to the surface of the preform for obtaining the stretch-molded substrate 101 and then stretch-molded to form the stretch-molded substrate 101 to form the barrier coating 103 . Forming the coating 103 is most suitable for taking advantage of the properties of this barrier coating 103 .

In FIG. 1, the barrier coating 103 is formed on one surface of the stretch-molded substrate 1, but the barrier coating 103 may be formed on both sides of the stretch-molded substrate 1 depending on the usage.

<Cover molding 105>
By the way, since the barrier coating 103 described above is formed from an oxidizable organic compound, it has an extremely high oxygen-blocking property due to oxygen absorption. Power will be exhausted in a short period of time. Therefore, as shown in FIG. 2, it is preferable to have a double structure in which a cover molding 105 is provided so as to cover this barrier coating 103 .

In the present invention, the cover molding 105 is provided so that the barrier coating 103 is not directly exposed to the atmosphere. It may be a resin film provided with a vapor-deposited film of metal oxide, or a metal foil. , is most preferably a stretch molded product.
That is, when the cover molded body 105 is formed of a stretched molded body, a stack plate is obtained by stacking a preform for obtaining this cover molded body on a preform for the stretched molded body 101 provided with the barrier coating 103. This is because the cover molding 5 can be obtained at the same time as the stretch-molded substrate 101 provided with the barrier coating 103 by reforming and stretching using this stack preform.

<Preferred form of stretched structure 100 using double structure>
The stretched structure 100 having a double structure as shown in FIG. 2 described above can be applied to various forms, but is particularly suitable as a double structure container molded by biaxial stretch blow molding. used.

A form of such a double structure container is shown, for example, in FIG.
In FIG. 3, the double structure container to which the stretched structure 100 having the above double structure is applied is indicated by 10 as a whole. A barrier coating 5 is provided between the inner surface of the outer container 1 and the outer surface of the inner container 3. In this example, the outer container 1 may correspond to the cover molded body 105, and the inner container 3 may correspond to the stretch-molded substrate 101, or vice versa. Also, the barrier coating 5 in FIG. 3 is the same as the barrier coating 103 in FIG.

In FIG. 3, 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 if necessary, and a depressed squeeze region is formed in the central portion of the body portion 1b for easy squeezing.

Further, in the example of FIG. 3, a support ring 1d is formed on the outer surface of the neck portion 1a of the outer container 1. As shown in FIG.

On the other hand, the inner container 3 has a neck portion 3a which is a non-stretched portion and a thin body portion 3b which is blow-stretched. It is in close contact with the inner surfaces of the body portion 1b and the bottom portion 1c of 1.
In such an inner container 3, the neck portion 3a is fitted into the neck portion 1a of the outer container 1, and in the example of FIG. A screw 3c for screwing the cap is formed on the projecting portion, and a projection 3d serving as a stopper is formed below the screw 3c to prevent the inner container 3 from deeply entering the outer container 1. is formed.
Of course, the form of the double structure container 10 to which the present invention is applied is not limited to the form shown in FIG. It is also possible to provide a screw for attaching a cap to the outer surface of the neck portion 1a of the outer container 1 (upper portion of the support ring 1d).

In the present invention, the outer container 1 and the inner container 3 described above are made of blow-moldable thermoplastic resins, such as olefin resins and polyester resins, particularly ethylene terephthalate polyesters, which are suitably used for packaging materials. there is

In the double structure container 10 to which the present invention is applied, as shown in FIG. 3, a barrier coating 5 corresponding to the barrier coating 103 exists between the inner surface of the outer container 1 and the outer surface of the inner container 3. I am doing it.
That is, the coating 5 effectively suppresses permeation of oxygen into the inner container 3, effectively avoids oxidative deterioration of the contents accommodated in the inner container 3, and maintains the freshness of the contents for a long period of time. can.

Since the double structure container 10 described above is provided with the coating 5 as described above, it is manufactured by a so-called stack preform method.
That is, a first preform (outer container molding preform) obtained by injection molding using a resin for the outer container 1 and a first preform obtained by injection molding using a resin for the inner container 3. 2 preforms (preforms for molding the inner container) are used, the second preform is inserted into the first preform to form a multi-layered stack preform, and the stack preform is biaxially stretched. It is manufactured by a method of performing blow molding.
That is, according to this method, the coating 5 can be easily formed on the outer surface of the second preform or the inner surface of the first preform.

4 and 5 for explaining the above stack preform method, the stack preform for molding the double structure container of FIG. 3 is generally indicated by 20 in FIG. As shown, the first preform 11 (see FIG. 4(a)) and the second preform 13 (see FIG. 4(b)) both having a test tube shape are formed.
That is, the first preform 11 is a preform for molding the outer container, the second preform 13 is a preform for molding the inner container, and the second preform 13 is inserted into the first preform. The stack preforms 20 to be subjected to the blow-stretching process are assembled by fitting and holding them together.

As understood from FIG. 4, both the first preform 11 and the second preform 13 have portions 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 parts is stretch-molded. The first preform 11 has a support ring 1d, and the second preform 13 has a screw 3c and a projection 3d.
In addition, the lower end of the lower portion of the neck portion 1a of the first preform 11 is a portion to be stretch-molded, and the closed body portion 11b is formed into the shape of the body portion 1b and the bottom portion 1c of the outer container 1 by blow-stretching. shaped.
Further, the lower end of the lower portion of the neck portion 3a of the second preform 13 is a portion to be stretch-molded, and the closed body portion 13b is formed into the shape of the body portion 3b of the inner container 3 by blow-stretching. . That is, the coating 5 (barrier coating 103) of the oxidizable organic compound is formed by coating on the portion that will become the body portion 3 by stretching.

By inserting the second preform 13 into the first preform 11, the stack preform 20 having the configuration shown in FIG. The portion including 1a and 3a is fixed (the region indicated by X in FIG. 5), and the stack preform 20 is heated to a temperature at which the stack preform 20 can be stretch-molded (the glass transition temperature of the resin forming the preforms 11 and 13). A stretch rod (not shown) is inserted into this stack preform 20 (second preform 13) to stretch it uniaxially, and then blown with air or the like. By supplying a fluid and expanding in the circumferential direction, the double structure container 10 having the configuration shown in FIG. 3 is obtained. That is, in FIG. 5, the region indicated by Y of the stack preform 20 is the stretch-molded portion.

In the present invention, the barrier coating 5 can be easily formed between the outer container 1 and the inner container 3 by molding the double structure container 10 by the method as described above. It can be formed without kneading or melt molding. In other words, it is possible to effectively exhibit the oxygen blocking property due to this oxygen absorption without causing deterioration of the oxidizable organic compound.
At the time of such blow stretch molding, since the coating 5 has stretch followability, it is stretched together with the first preform 11 and the second preform 13 without causing film breakage or the like, and a predetermined region is formed. can be provided with a coating 5 of uniform thickness.

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

In the double structure container 10 to which the present invention is applied, the content filled in the inner 3 squeezes (presses) the recessed portion (squeeze region) of the body 1b of the outer container 1, for example. As a result, the contents are discharged one by one by the amount depressed by the pressure, and the contents are discharged and the volume of the body portion 3b of the inner container 3 is reduced. Since air is introduced between the inner surface of the portion 1b and an air layer is formed, the subsequent discharge of the contents is also effectively performed.
In such a bottle, the coating 5 can effectively suppress and prevent the intrusion of oxygen into the inside from the body portion 3b of the inner container 3, and can effectively prevent the oxidative deterioration of the contents.

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

1. Material <Polyester resin (A)>
Isophthalic acid (copolymerization ratio = 1.8 mol%) copolymerized polyethylene terephthalate resin (5015W: manufactured by Shinko Synthetic Fibers, IV = 0.83)

<Coating component (B)>
(1) Synthesis of oxidizable organic compound <Raw material for oxidizable organic component (BX)>
A methyltetrahydrophthalic anhydride mixture (HN-2200: manufactured by Hitachi Chemical Co., Ltd.) containing 45% by weight of 4-methyl-Δ3-tetrahydrophthalic anhydride and 21% by weight of cis-3-methyl-Δ4-tetrahydrophthalic anhydride was coated. It was used as a raw material for oxidizable organic compounds.

(Synthesis example 1)
A 1000 mL four-necked separable flask equipped with a stirrer, a nitrogen inlet tube and a dropping funnel was charged with 250 g of the oxygen-absorbing component raw material (BX). An amine component dissolved in 200 mL of ethanol; 101 g of meta-xylene diamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was gradually added thereto. After the entire 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 oxidizable organic compound (B1).
(Synthesis example 2)

Synthesis was carried out in the same manner as in Synthesis Example 1, except that 250 g of (BX), 87.1 g of hexamethylenediamine, and 200 mL of ethanol were charged to obtain an oxidizable organic compound (B2).

(Synthesis Example 3)
In a 3 L separable flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark type water separator, (BX) as an acid component at a molar ratio of 0.9 and succinic anhydride as other acid components at a molar ratio of 0.1 , 1,4-butanediol as a diol component at a molar ratio of 1.3, and 300 ppm of isopropyl titanate as a polymerization catalyst were charged, and reacted for about 6 hours in a nitrogen atmosphere at 150°C to 200°C while removing water generated. . Subsequently, polymerization was carried out at 200 to 220° C. for about 3 hours under a reduced pressure of 0.1 kPa to obtain an oxidizable polyester resin (B3). The oxidizable polyester resin (B3) had an Mn of 5,200 and an Mw of 76,600.

(2) Other Oxidizable Organic Compounds As other oxidizable organic compounds, oleic acid (manufactured by Wako Pure Chemical Industries) (B4) and ascorbic acid (manufactured by Wako Pure Chemical Industries) (B5) were used.

(3) Other materials used Liquid paraffin (manufactured by Kishida Chemical Co., Ltd.) (B6) was used.

2. Measurement/Evaluation Method (1) Dissolved Oxygen Concentration Oxygen-free water with an oxygen concentration of 0.1 ppm or less was prepared using an oxygen-free water generator (LOW DISSOLVED OXYGEN: manufactured by Miura Kogyo Co., Ltd.). It was filled to the brim and sealed with a plastic cap. After storage at 23° C. and 50% RH for 28 days, the concentration of dissolved oxygen in water in the bottle was measured with a nondestructive high-sensitivity oxygen concentration meter (Oxy-4 Trace v3: manufactured by Presens). As a judgment of the oxygen barrier property, the dissolved oxygen concentration at this time was clearly lower than that of Comparative Example 1 (less than 2.00 ppm), and the same as Comparative Example 1 (2.00 ppm or more) was evaluated as ×. .

(2) Viscosity Among the oxidizable organic compounds, those that are liquid at 100° C. were measured for viscosity at 100° C. with a Brookfield rotational viscometer (RV-DV2T, manufactured by Brookfield). SC4-27 was used as the spindle, and the rotation speed was 150 rpm for the oxidizable organic compound (B1) and 200 rpm for the oxidizable polyester resin (B3) except for 5 rpm.

(3) Stretch followability Visually observe the produced biaxially stretched blown bottle. If the coating between the inner container and the outer container was uniformly stretched without cracks, it is marked as “○”. In the case of

(Example 1)
A 17 g preform for molding an outer container and a 12 g preform for molding an inner container for a double structure container were obtained by injection molding using the polyester resin (A) described in the materials used above. Next, the oxidizable organic compound (B1) dissolved in ethanol is applied to the outer surface of the preform for molding the inner container, dried with a dryer, the preform for molding the outer container is layered, and the preform is biaxially stretched and blown into a 500 mL bottle. Molded.

(Example 2)
A biaxially stretched blow bottle was obtained in the same manner as in Example 1, except that the oxidizable organic compound was changed to (B2) and coating was performed without using an organic solvent.

(Example 3)
A biaxially stretched blow bottle was obtained in the same manner as in Example 1, except that the oxidizable organic compound was changed to (B3), dissolved in ethyl acetate and applied.

(Example 4)
A biaxially stretched blow bottle was obtained in the same manner as in Example 2 except that the outer surface of the preform for molding the inner container was previously subjected to oxygen plasma treatment and the oxidizable organic component was changed to (BX).

(Example 5)
A biaxially stretched blow bottle was obtained in the same manner as in Example 1, except that the oxygen absorbing component was changed to (B4).

(Comparative example 1)
A biaxially stretched blow bottle was obtained in the same manner as in Example 1, except that the outer surface of the preform for molding the inner container was not coated.

(Comparative example 2)
In the same manner as in Example 1, except that the outer surface of the inner container molding preform was previously subjected to oxygen plasma treatment, the oxidizable organic compound was changed to (B5), and (B5) was applied in the form of an aqueous solution. A biaxially stretched blown bottle was obtained. However, the coating layer of (B5) did not follow the stretching, and cracks that could be visually confirmed were generated in the entire coating layer.

(Comparative Example 3)
A biaxially stretched blow bottle was obtained in the same manner as in Example 2, except that the component coated on the outer surface of the preform for molding the inner container was changed to (B6).

Table 1 shows the weight of the coating components used, the stretch followability of the coating layer when producing the biaxially stretched bottle, and the dissolved oxygen concentration of the bottle stored at 23° C. for 28 days by the oxygen-free water method.

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

Claims (10)

A stretch-molded structure comprising a stretch-molded substrate and a barrier coating formed on the stretch-molded substrate surface and containing an oxidizable organic compound having stretch-following properties ,
A stretch-formed structure, wherein the barrier coating is a non-binder coating containing 75% by mass or more of the oxidizable organic compound. 2. The stretch-formed structure according to claim 1, wherein the barrier coating is a non-binder coating containing 90% by mass or more of the oxidizable organic compound. 3. The stretch-molded structure according to claim 1 or 2, having a double structure in which a cover molded body is superimposed on the barrier coating of the stretch-molded substrate. 4. The stretch molded structure according to claim 3, wherein the cover molded body is a stretch molded body. The stretch-molded structure according to any one of claims 1 to 4, wherein the oxidizable organic compound exhibits fluidity at a stretch-molding temperature. 5. The stretch-formed structure according to claim 4, wherein the oxidizable organic compound has a viscosity at 100° C. in the range of 1 to 30000 mPa·s. The oxidizable organic compound has the following formula (1):

wherein 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, amide, imide or dicarboxylic acid derived from the acid anhydride, and a polymer having a structural unit derived from the acid anhydride 7. A stretch-formed structure according to Item 6. A stretch formed structure according to any preceding claim, wherein the barrier coating is a transition metal catalyst free coating. The stretch-molded structure according to any one of claims 1 to 8, wherein the stretch-molded substrate is made of ethylene terephthalate-based polyester. A double structure stretch molding preform comprising a first stretch molding preform and a second stretch molding preform superimposed on the first stretch molding preform,
a stretch-following barrier coating comprising an oxidizable organic component is present between the first stretch-molding preform and the second stretch-molding preform ;
A preform for stretch molding with a dual structure , wherein the barrier coating is a non-binder coating containing 75% by mass or more of the oxidizable organic compound .

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