JP2001270563A - Composite container and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite container provided with a plastic interior container having its outside coated and bonded with an exterior container formed of a resin impregnated paper and not only provided with strength improved to a large extent and stronger than the container strength of composite containers heretofore available but also securing the sufficient container strength by reducing the lowering of the strength of the exterior container to a large extent by using a resin impregnated paper for the container and also provided with water resistance and hot water resistance even when the composite container is wet and also when the role of use as the container is completed for the composite container, a plastic member of an interior container can be easily separated from the paper member as the exterior container and thrown away. SOLUTION: The composite container is characterized by being formed of an interior container 1 formed of a plastic and coated with the exterior container 2 formed of the resin impregnated paper and bonded thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to the storage of toiletries such as detergents for fabrics, softeners, shampoos and rinses, and the contents of beverages, foods, cosmetics, etc.
The present invention relates to a composite container covered and joined with an inner container made of plastic and an outer container made of paper, and more particularly to a composite container in which the outer container uses resin-impregnated paper.

[0002]

2. Description of the Related Art In recent years, environmental problems have become serious and containers and packaging materials have to be easily disposed of, and demand for easy incineration, recyclability, or use of recycled materials is increasing. Therefore, a composite container in which the outside of a plastic container is covered with paper has been proposed. Also, there have been proposed various types of composite containers in which the amount of plastic used is greatly reduced, and composite containers capable of separating paper and plastic at the time of disposal.

[0003] Composite containers made of plastic and paper tend to use as little plastic as possible for interior containers in order to cope with environmental issues and resource saving. For this reason, the strength physical properties of the inner container itself are greatly reduced, and the strength physical properties of the container itself are secured by combining a paper outer container and a plastic inner container.

[0004] Conventional composite containers are typically bottles and trays, and these composite containers sometimes require physical properties equivalent to those of conventional plastic bottles and plastic trays, especially buckling strength of the containers. It is general that the inner container and the outer container are integrated by joining with an adhesive or the like. In a composite container in which the amount of plastic resin used has been reduced to near the limit, a paper member having a relatively large basis weight as an outer container and / or a high-strength paper manufactured from virgin pulp to ensure buckling strength. Members, for example, paper members such as so-called milk base paper used for milk pack applications and the like are generally used.

However, in a conventional composite container,
The water resistance of the outer container, especially when the water is absorbed from the end face of the paper member, the strength of the paper substrate is remarkably reduced, and it is hard to say that the paper base has water resistance. Further, in order to impart water resistance to the composite container, the strength of the entire container when wet is ensured without greatly reducing the amount of resin used in the interior container.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a composite container in which an outer container made of plastic is covered and joined with an outer container made of paper. The use of impregnated paper not only significantly improves the strength of the conventional composite container, but also ensures sufficient container strength by drastically reducing the strength of the outer paper container even when the composite container becomes wet. Another object of the present invention is to provide a composite container having water resistance and hot water resistance. Another object of the present invention is to provide a composite container that can easily separate and discard the plastic member of the inner container and the paper member of the outer container when the composite container has been used as a container.

[0007]

The above objects can be attained by the following means.

According to a first aspect of the present invention, there is provided a composite container wherein an outer container made of paper is covered and joined to an outer container made of plastic, wherein the outer container is made of resin-impregnated paper. This is a composite container.

According to a second aspect of the present invention, there is provided a composite container characterized in that the outer container made of paper is made of resin-impregnated paper which is a pulp molded article.

[0010] A third invention of the present invention is directed to the first or second invention of the present invention, characterized in that the resin-impregnated paper used for the outer container is made of paper to which a resin is internally added in a papermaking stage. It is a composite container as described.

[0011] A fourth invention of the present invention is the first or second invention of the present invention, characterized in that the impregnated paper used for the outer container is made of paper to which a resin is externally added after papermaking. In a composite container.

[0012] The fifth invention of the present invention is the above-mentioned impregnated paper,
The composite container according to any one of the first to fourth inventions of the present invention, wherein the resin to be impregnated is an isocyanate-based resin.

According to a sixth aspect of the present invention, there is provided the composite container according to the fifth aspect of the present invention, wherein the isocyanate-based resin comprises either xylylene diisocyanate or isophorodiisocyanate, or a mixture thereof. It is.

According to a seventh aspect of the present invention, as the impregnated paper,
The composite container according to any one of the first to fourth inventions of the present invention, wherein the resin to be impregnated is a polyolefin resin.

According to an eighth aspect of the present invention, there is provided any one of the first to seventh aspects of the present invention, wherein the interior container is made of two or more materials and has a laminated structure of two or more layers. Or a composite container according to the invention.

According to a ninth aspect of the present invention, the weight ratio of the resin used for the inner container to the resin impregnated in the impregnated paper used for the outer container is less than 50% of the total weight of the container. A composite container according to any one of the first to eighth inventions of the present invention.

According to a tenth aspect of the present invention, there is provided the composite container according to any one of the first to ninth aspects of the present invention, wherein the shape of the composite container is a bottle. is there.

An eleventh invention of the present invention is the composite container according to the tenth invention of the present invention, characterized in that said interior container is a bottle formed by blow molding or stretch blow molding.

A twelfth aspect of the present invention is the composite container according to any one of the first to ninth aspects of the present invention, wherein the composite container is a tray.

A thirteenth invention of the present invention is the composite container according to the twelfth invention of the present invention, wherein said interior container is a tray formed by vacuum forming or pressure forming.

According to a fourteenth aspect of the present invention, any one of the first to thirteenth aspects of the present invention is characterized in that the joint between the outer container and the inner container is completely bonded.
A composite container according to the invention.

According to a fifteenth aspect of the present invention, the joint portion between the outer container and the inner container has an area ratio of 20% to 70% with respect to the entire inner area of the outer container. To a composite container according to any one of the thirteenth invention to the thirteenth invention.

According to a sixteenth aspect of the present invention, in the composite container, an outer container is inserted into a mold, an inner container is molded inside the mold, and the outer container and the inner container are joined. A method for producing a composite container according to any one of the first to fifteenth aspects of the present invention.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in more detail.

The present invention, as shown in FIGS.
A composite container in which the outside of an inner container 1 made of plastic is covered and joined with an outer container made of paper, wherein the outer container is made of resin-impregnated paper.

The impregnated paper used for the outer container is 100% bar
It is possible to use paper bases of various types of base papers, such as those from gin pulp, coat balls containing waste paper, and those coated with clay on one side. These paper substrates are impregnated with a resin capable of imparting rigidity, water resistance and hot water resistance by internal addition and spraying at the papermaking stage, or external addition as a secondary processing after papermaking. However, the paper substrate here includes all plate-like fiber structures made of pulp,
It is not limited to the so-called paper type. The thickness may be appropriately selected in the range of 20 g / m2 to 600 g / m2 according to the purpose.

The impregnated paper to be used as the outer container can be formed into a pulp molded article. Similar to the above-mentioned resin impregnation method, rigidity, water resistance and heat resistance can be obtained by internal addition, external addition, spraying and the like. Can be impregnated.
By using a pulp molded body for the outer container, lamination and crease folding are not required. For this reason, it is possible to eliminate the exposure of the end face of the paper at the bonded portion, the bent portion of the ruled line, and the like, which are inevitably included in the molded paperboard. Further, by using the pulp molded article for the outer container, the shape of the composite container can be freely selected according to the rigidity and design of the container, such as a cylindrical shape and an oval shape.

Examples of the resin for impregnating the paper base include polyvinyl alcohol resin, polyacrylamide, and the like which can impart dry strength, water resistance, and wet strength of the paper base.
Starch, etc., and as a paper strength enhancer when wet, urea formaldehyde resin, melamine formaldehyde resin,
Starch, polyamidoamine, epichlorohydrin modified product thereof, and various latexes such as natural rubber latex, synthetic rubber latex such as SBR, NBR, polychloroprene, polyvinyl acetate, acrylic resin, polyvinyl chloride, polyvinylidene chloride or a copolymer thereof. Polymer resin latex or the like is used.

Further, as resins capable of imparting hot water resistance, in addition to thermosetting resins such as silane resins and melamine resins, thermoplastic resins such as acrylic resins, polyester resins, polyethylene resins and polypropylene resins are also required. It can be selectively used depending on the temperature of the heat resistant water to be used. Also, even when water repellency is required as an additional function, unless the required hot water resistance is impaired,
It is also possible to use a composite or a mixture of the above resin materials according to the required function level.

The resin material of the plastic container serving as the interior container includes a polyethylene terephthalate resin, a polyethylene naphthalate resin or a mixture thereof, a polyolefin resin such as a polyethylene resin, a polypropylene resin, a cyclic polyolefin resin, and the like. Any resin, such as acrylonitrile resin, can be selected as long as it can be vacuum-molded, compressed-air molded, injection-molded, and blow-molded. That is, the present invention is not based on a method for manufacturing a plastic container or a plastic container inside a composite container.

It is also possible to use a laminate having a resin layer on one side of the impregnated paper or on both sides of the paper. A configuration in which a polyethylene resin or a polypropylene resin is laminated on the outer surface of the impregnated paper as the outer container. Is preferably used. Furthermore, in addition to the polyolefin resin such as polyethylene or polypropylene, a barrier resin such as a polyester resin, a polyamide resin or an ethylene-vinyl alcohol copolymer alone or a composite film combining these resins is also provided on the inner surface side. Etc. can also be used.

That is, by imparting rigidity, water resistance and hot water resistance to the paper base material, the rigidity of the outer container during drying can be improved.
It aims to increase the rigidity when wet and hot water.
As a result, the container strength of the composite container can be greatly improved, and even if the composite container becomes wet, sufficient reduction in the strength of the outer paper container is significantly reduced to ensure sufficient container strength, and the composite has water resistance and hot water resistance. Get the container.

The impregnated paper used for the outer container is made of paper in which a resin is internally added to a paper base in a paper making stage, or paper in which a resin is externally added after the paper is made in a paper base.

By impregnating or internally adding the impregnated paper in the paper making process, the above-mentioned resin can be evenly distributed over the entire thickness of the paper member. In addition, by impregnating the resin at the papermaking stage, the density and thickness of the impregnated paper, the amount of resin to be internally added, and the like can be arbitrarily determined according to the functional level of the paper member desired as the composite container. In the case where the impregnated paper is made by multilayer papermaking or when it is molded into a pulp molded article, the impregnated paper may be sprayed between layers during papermaking.

When the impregnated paper is obtained by external addition, the type of paper base used is 100% virgin pulp, a coat ball composed of waste paper, a part of recycled waste paper, NBKP It is possible to use various types of base paper, such as wood and LBKP material usage, kenaf other than wood pulp, paper made from bamboo, and paper coated on one side with clay coating. The paper substrate here includes all fiber structures made of pulp, and is not limited to the type and shape of so-called paper. The shape may be a three-dimensional molded body such as a pulp mold from a plate-like sheet. Good. That is, what can be used as the substrate may be arbitrarily selected depending on the shape of the composite container, the type and the weight of the contents.

Then, a resin capable of imparting rigidity, water resistance and hot water resistance is impregnated as secondary processing after papermaking. As the impregnation method by this external addition, there are a dipping method in which the fiber structure is immersed in the impregnating agent and an excessive amount of the impregnating agent is temporarily applied, and a method in which the fiber structure is sprayed with the impregnating agent in an intended amount. . Further, when the fibrous structure is paperboard, preferably, there is a gravure coating method or a roll coating method of coating or impregnating a fixed amount of the impregnating agent, and impregnating the impregnating agent from the front and back of the base fiber structure. It is also possible.

In the gravure impregnation method having two or more units, an impregnating agent for impregnating the inside of the paper substrate is first applied from one side or both sides, and the impregnating agent penetrates into the inside of the substrate. The last unit after that enables the formation of a coating film layer on the surface of the paper substrate. The impregnated paper thus obtained has a high wet strength, for example, by impregnating a wet paper strength enhancer or the like over the entire inside of the impregnated paper, and has a high water repellency by disposing a water repellent agent or the like on the impregnated paper surface layer. Can have an effect. That is, any method can be arbitrarily selected according to the type of the paper substrate and the impregnating agent, as long as the method can supply the impregnating agent to the paper substrate. Further, since these processes are performed in a secondary process, a small amount of processing can be performed at a lower cost as compared with the papermaking process.

The resin impregnated into the paper base as the impregnating agent
It is preferable to use an isocyanate-based resin in order to improve water resistance and heat resistance.

This isocyanate resin improves the wet strength of the paper by impregnating the paper. The urea compound formed by the isocyanate and the moisture in the paper is extremely high in heat resistance and water resistance. It has a hot water resistance, and the water absorption can be significantly reduced.
By using an isocyanate resin-impregnated paper as the outer container, the composite container is extremely excellent in shape retention, buckling strength, etc. even when the composite container is only in a dry state or in a wet state. Also, in the boil sterilization and retort sterilization processes, a composite container using an isocyanate resin-impregnated paper as an outer container exhibits extremely high shape retention under hot water conditions and has hot water resistance.

As the isocyanate resin to be impregnated, various polyisocyanate compounds which have been hitherto known, for example, phenylene diisocyanate (PD)
I) aromatic diisocyanates such as tolylene diisocyanate (TDI), naphthalene diisocyanate (NDI), 4,4 'diisocyanate diphenylmethane (MDI), aromatic aliphatic diisocyanates such as xylylene diisocyanate (XDI), hydrogenated TDI, Hydrogenated XD
I, hydrogenated MDI, hexamethylene diisocyanate (H
(MDI) aliphatic or alicyclic diisocyanates such as isophorone diisocyanate (IPDI) and derivatives thereof such as polyol adducts, burettes, trimers, trifunctional or higher functional polyisocyanates, and lysine triisocyanates (LTI); In addition to functional isocyanates, various oligomers and polymers containing isocyanates can be used. Among these, when a composite container using this impregnated paper is used for food applications, it is preferable to use either XDI or IPDI, or a mixture thereof.

As the impregnated paper other than the isocyanate resin, a paper impregnated with a polyolefin resin can be used.

As the polyolefin resin, polyethylene resin, polypropylene resin and the like are preferably used.
The polyolefin-based resin-impregnated paper exhibits heat resistance, water resistance, and hot water resistance similarly to the above-described isocyanate resin-impregnated paper, and these impregnated resins may be selected according to the required heat resistance temperature. .

Since these polyolefin resins are thermoplastic resins, the polyolefin resins are re-melted by heating the impregnated papers in the step of producing an exterior impregnated paper or in the step of forming a composite container.
It penetrates well into the surface and inside of the fiber of the paper substrate, and can improve water resistance and the like. Also, in the process of forming the composite container, the end portion and the joint of the impregnated paper to be the outer container (back bonding, seam)
By performing thermocompression bonding, the voids of the fibrous structure can be eliminated from the vicinity of the end of the impregnated paper, and the water absorption from the end face of the impregnated paper can be significantly reduced.

On the other hand, various functions can be imparted to the interior container by using not only a single plastic material but also a laminate structure of two or more layers of two or more materials.

As the resin used for the inner container of the composite container, a polyester resin or the like is used in addition to a polyolefin resin such as a polyethylene resin or a polypropylene resin. By using these resins and barrier resin such as polyamide resin and ethylene-vinyl alcohol copolymer in two or more multi-layered interior container, oxygen barrier property and fragrance retention property can be obtained in the composite container. Can be provided. Here, in the composite container of the present invention, the weight ratio of the resin impregnated in the paper of the inner container and the outer container is preferably less than 50% of the total weight of the composite container.

By using the resin-impregnated paper as the outer container as described above, the rigidity of the container when dry and the rigidity when wet are increased. Therefore, the composite container can significantly reduce the thickness of the plastic container as the interior container, and has a sufficient container strength even when the amount of resin used in the entire container is less than 50%. More preferably, depending on the content to be filled and the method of molding the interior container, the amount of resin used can be less than 30%,
A sufficient container strength can be provided even when dry or wet.

Examples of the shape of the composite container include a bottle shape shown in FIG. 1 and a tray shape shown in FIG. 2, but are not limited thereto.

In order to form a bottle-shaped composite container, first, the interior container 1 is formed into a bottle shape, and in order to obtain the bottle shape, a container having a predetermined shape is formed by blow molding or stretch blow molding. .

Further, in order to form the tray-shaped composite container shown in FIG. 2, the inner container 1 is formed in a tray shape. This interior container can be obtained by vacuum forming or pressure forming.

In the composite container of the present invention, it is preferable that the inner container 1 and the outer container 2 are joined, and the joined portion is completely bonded.

When used as an inner container subjected to retort treatment or boil treatment, the appearance and strength of the container are not significantly reduced in the hot water treatment step, depending on the shape, contents and weight of the composite container. I do. Therefore, by completely bonding the outer container and the inner container of the composite container, the hot water can permeate the composite container only on the surface of the outer container and the end of the composite container, and the strength of the composite container is greatly reduced. Can be reduced. Further, even when used as a simple tray for food or the like, the strength of the tray can be maintained sufficiently because the impregnated paper forming the outer container and the plastic container forming the inner container are completely bonded. .

The joint portion of the composite container is set to 20% to 70% in area ratio to the inner area of the outer container.

The composite container of the present invention has such a bonding area ratio that it can withstand the use environment and can provide the disposal property and the separation property after use.

This joint area ratio varies depending on the purpose of use. For example, when a composite container is used in a bathroom as a container for shampoo, rinse, body soap, etc., the ratio differs depending on the container shape and content. Area ratio is 3
It may be about 0%, and more preferably, the bonding area ratio is 20%.
By making it halftone dot or stripe at 40%,
The outer container can be separated from the inner container. Further, the ease of separation depends on the adhesive used and the adhesive shape, but here depends on the adhesive area ratio, and is not limited to the adhesive or the adhesive shape.

The bottle-shaped or tray-shaped composite container is preferably formed by molding an inner container and a plastic container inside a mold in which an outer container is inserted.

In the case of producing a bottle-shaped composite container, it is particularly preferably formed by blow molding, stretch blow molding, or injection stretch blow molding. The number of steps can be reduced by inserting the inside of the mold and forming the interior container made of a plastic container inside the mold, and a composite container can be obtained.

In the case of manufacturing a tray-shaped composite container, it is particularly preferably formed by vacuum sheet molding or pressurized sheet molding. However, an adhesive is previously applied to the outer surface of the resin sheet serving as the interior container, and impregnation is performed. The number of steps can be reduced by molding the inner container made of a plastic container after inserting the outer container made of paper into the mold,
A composite container can be obtained.

[0058]

Next, specific embodiments of the present invention will be described in detail below.

<Example 1> A coated ball base paper having a basis weight of 310 g / m2 was used as a paper base material of an impregnated paper used for an outer container, and an isocyanate resin was impregnated by a dipping method to obtain an impregnated paper. The impregnated paper was further printed, and a polyethylene resin was extruded on both sides by extruding and laminating. Further, an adhesive was applied to the inner surface of the container in a halftone dot form so as to be 30% of the joint area. It was punched out to form a bottle-shaped outer container, and the back affixed portion was bonded with an adhesive to obtain an outer container of the composite container of the present invention. This exterior container is inserted into a mold of a stretch blow molding machine, and a preform previously injection-molded with a polypropylene resin is molded and molded into an interior container by stretch blow molding, and is simultaneously adhered to and integrated with the exterior container. A composite container was obtained. The capacity of the composite container is 250 ml. The obtained composite container was sufficiently resistant to use in a bathroom as a shampoo container and a rinse container. Further, the outer paper container was not separated from the inner plastic container in all steps from filling, capping, distribution and consumption of the contents required for the conventional plastic container. In the composite container after the use of the contents, the outer container and the inner container could be easily separated, and the impregnated paper serving as the outer container and the plastic container serving as the inner container could be separately discarded.

Example 2 An uncoated cup base paper having a basis weight of 300 g / m 2 was used as a paper base material of impregnated paper used as an exterior container, and an isocyanate resin was impregnated from both sides of the paper base material by a gravure coating method. An impregnated paper was obtained. The impregnated paper was further printed. This was punched out into a tray-shaped outer container to obtain an outer container of a composite container. This outer container is inserted into a mold of a vacuum sheet molding machine, and vacuum forming is performed on a sheet of a polypropylene / EVOH / polypropylene structure in which an adhesive is applied in advance on a side to be an outer surface of the inner container. They were adhered to obtain a tray-shaped composite container. The capacity of the composite container is 200m
l. The obtained composite container was filled with food and retorted after the lid material was sealed, but the composite container has sufficient strength even in hot water treatment, and the end surface of the impregnated paper, such as delamination, etc. There was no appearance defect, and it could withstand retort processing sufficiently. The tray-shaped composite container is
It could be used as a simple tray container when eating the contents. (EVOH: saponified ethylene-vinyl acetate)

Example 3 An uncoated cup base paper having a basis weight of 300 g / m 2, in which a polypropylene resin was internally added and mixed, was used as a paper base material of impregnated paper used as an outer container. The polypropylene-impregnated paper was further printed. This was punched out into a tray-shaped outer container in the same manner as in Example 2 to obtain an outer secondary container of a composite container. Example 2
In the same manner as in the above, vacuum forming was performed with a sheet having a polypropylene / EVOH / polypropylene structure, and at the same time, the sheet was adhered to an outer secondary container to obtain a tray-shaped composite container. The capacity of the composite container is 200 ml. The obtained composite container was filled with food and retorted after the lid material was sealed, but the composite container has sufficient strength even in hot water treatment, and the end surface of the impregnated paper, such as delamination, etc. There was no appearance defect, and it could withstand retort processing sufficiently. In addition, the tray-shaped composite container can be used as a simple tray container when eating the contents. (EVOH: saponified ethylene-vinyl acetate)

Example 4 LBKP as an outer container was internally added with a paper strength enhancer, and a three-dimensional molded product (bowl-shaped) was obtained by a pulp molding method. The three-dimensional molded product was impregnated with a xylene diisocyanate resin by a dipping method to obtain an impregnated molded product. This was put into a vacuum forming machine, and vacuum forming was performed on the side to be the outer surface of the inner container with a polypropylene sheet to which an adhesive was applied in advance, and simultaneously bonded to the outer container to obtain a bowl-shaped composite container. The capacity of the composite container is 250m
l. The contents were filled therein, the lid material was sealed, and hot water treatment at 95 ° C. for 30 minutes and cooling water treatment for 10 minutes were performed with a constant pressure sterilizer. The composite container had sufficient strength even in the hot water treatment, had no appearance defects such as delamination of the end face of the impregnated paper, and was sufficiently resistant to the retort treatment. In addition, the tray-shaped composite container can be used as a simple tray container when eating the contents.

<Comparative Example 1> Coated ball base paper having the same basis weight of 310 g / m2 was used as the paper for the outer container, and printing was performed, polyethylene resin was extruded on the front and back sides and laminated by laminating, and an adhesive was applied to the inner surface of the container. Was formed in the same material and method as in Example 1 except that the material was applied in a halftone dot form so as to be 30% of the bonding area. The capacity of the composite container is 250 ml. The obtained composite container was used in a bathroom as a shampoo container and a rinsing container. The obtained composite container had sufficient bonding between the inner container and the outer container, but had a large amount of water absorption from the end of the outer paper container, so that the container lost strength and was not usable.

[0064]

According to the present invention, in a composite container in which the outside of a plastic inner container is covered and joined with an outer container made of paper, the outer container is made of resin-impregnated paper, so that the container strength, water resistance, and heat resistance are improved. It has become possible to obtain a composite container having extremely excellent aqueous properties. Furthermore, by adjusting the ratio of the area of the joint portion in the joint portion / non-joint portion of the outer container and the inner container, a composite container having easy separation without any problem in strength at the time of use can be obtained. After completing the above, the easily detachable composite container can easily separate the inner container and the outer container. In the past, the inner container was separated and discarded, but the inner container and the outer container can be completely and easily separated, so that not only the outer container but also the inner container, that is, the entire container can be recycled.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a composite container of the present invention.

FIG. 2 is a sectional view showing another example of the composite container of the present invention.

[Explanation of symbols]

 1: interior container 2: exterior container

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichi Niimi 1-5-1 Taito, Taito-ku, Tokyo Inside Toppan Printing Co., Ltd. (72) Inventor Yoshiki Ueda 1-1-5-1 Taito, Taito-ku, Tokyo F-term (reference) in Toppan Printing Co., Ltd.

Claims (16)

[Claims] 1. An outer container made of plastic,
A composite container covered and joined with an outer container made of paper, wherein the outer container is made of resin-impregnated paper. 2. The composite container according to claim 1, wherein said outer container made of paper is made of a resin-impregnated paper that is a pulp molded article. 3. The composite container according to claim 1, wherein the resin-impregnated paper used for the outer container is made of paper to which a resin has been internally added in a paper making stage. 4. The composite container according to claim 1, wherein the impregnated paper used for the outer container is made of paper to which a resin is externally added after papermaking. 5. The composite container according to claim 1, wherein the resin to be impregnated as the impregnated paper is an isocyanate-based resin. 6. The composite container according to claim 5, wherein said isocyanate-based resin is made of one of xylylene diisocyanate and isophorodiisocyanate, or a mixture thereof. 7. The composite container according to claim 1, wherein the resin to be impregnated as the impregnated paper is a polyolefin-based resin. 8. The composite container according to claim 1, wherein the interior container is made of two or more materials and has a laminated structure of two or more layers. 9. The weight ratio between the resin used for the inner container and the resin impregnated in the impregnated paper used for the outer container is less than 50% of the total weight of the container. The composite container according to any one of the above. 10. The composite container according to claim 1, wherein the shape of the composite container is a bottle. 11. The composite container according to claim 10, wherein said interior container is a bottle formed by blow molding or stretch blow molding. 12. The composite container according to claim 1, wherein said composite container is a tray. 13. The composite container according to claim 12, wherein said interior container is a tray formed by vacuum forming or pressure forming. 14. A joint between the outer container and the inner container,
The composite container according to any one of claims 1 to 13, wherein the composite container is completely adhered. 15. A joint portion between the outer container and the inner container,
20% to 7 in area ratio to the entire inner area of the outer container
14. The method according to claim 1, wherein the value is 0%.
The composite container according to any one of the above. 16. The composite container according to claim 1, wherein an outer container is inserted into a mold, an inner container is molded inside the mold, and the outer container and the inner container are joined.
A method for producing a composite container according to any one of claims 15 to 15.