JP2000109123A - Container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a container which is easy in incineration and capable of landfill disposal after use, light in weight and excellent in heat insulation effect. SOLUTION: A container whose upper end is opened and which is provided with a cylindrical part and a bottom part is formed of a material of sandwich structure having an intermediate layer between both end members of an internal material and an external material. The intermediate layer is formed of base in which a pulp containing a recycled pulp and a binder whose binding property is inactivated through the hydrolysis are main raw materials of the three- dimensional network structure, and vacancies are contained inside, and thus the layer is high in heat insulation and easy in treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container having a cup shape, a tray shape, a bowl shape and the like used for foods and the like, and more particularly to a container having an opening at an upper end and having a cylindrical portion and a bottom portion. The present invention relates to a container made of a material having a sandwich structure having an intermediate layer between the base material and an outer material, the container having high heat insulation properties and easy processing.

[0002]

2. Description of the Related Art Conventionally, plastics are often used as materials for containers which have been used for the above-mentioned purposes, and include containers molded by injection molding and the like, and containers processed from expanded polystyrene sheets. In particular, the latter is lightweight and has excellent heat insulating properties, and is widely used. However, the plastic container has a problem in the processability after use, such as when used as a disposable container or the like.
That is, when the landfill treatment is performed after use, the decomposability is extremely low, so that it remains for a long time. It is also feared that high heat will damage the incinerator when incinerated in large quantities. On the other hand, there is a paper container as such a plastic substitute, but the heat insulation and strength are often insufficient.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above problems, that is, it provides easy incineration at the end of use, and also enables landfilling. Another object of the present invention is to propose a lightweight container having an excellent heat insulating effect.

[0004]

According to a first aspect of the present invention, there is provided a container having an opening at an upper end and having a cylindrical portion and a bottom portion, wherein an intermediate layer is provided between the inner and outer base materials. This intermediate layer is made of a pulp containing recycled pulp and a thickener whose binding is deactivated by hydrolysis as a main raw material of a three-dimensional network structure, and beads containing voids therein. It is a container characterized by high heat insulation and easy processing.

The invention according to claim 2 is the container according to claim 1, wherein the thickener constituting the beads of the intermediate layer is biodegradable.

According to a third aspect of the present invention, there is provided the container according to the first aspect, wherein voids inside the beads of the intermediate layer are bubbles derived from a decomposable foaming agent.

According to a fourth aspect of the present invention, there is provided the container according to the first aspect, wherein voids inside the beads of the intermediate layer are bubbles derived from a surfactant.

According to a fifth aspect of the present invention, there is provided the container according to the first, second or third aspect, wherein the space formed by the inner material and the outer material is filled with the beads.

The invention according to claim 6 is characterized in that the beads of the intermediate layer are fixed to at least one of the base material of the inner material and the outer material. Container.

Further, claims 7, 8 and 9 relate to the feature relating to the adhesion between the beads and the base material. In claim 7, the beads of the intermediate layer have an adhesive substance interposed therebetween, and are bonded to the base material of the inner material or the outer material. The container according to claim 6, wherein the container is configured to be combined.

In a preferred embodiment, the beads of the intermediate layer are beads having a surface provided with a thermoplastic resin layer, and are formed by being bonded to a base material through the thermoplastic resin layer. A container according to claim 7.

According to a ninth aspect, the beads of the intermediate layer are beads having a surface provided with a thermoplastic resin layer containing expandable hollow particles, and are bonded to a base material through the thermoplastic resin layer. 9. The container according to claim 8, wherein

The invention according to claim 10 is the container according to any one of claims 1 to 9, wherein the base material of the external material is paper.

According to a eleventh aspect, the container according to any one of the first to ninth aspects, wherein the base material of the outer material is a resin film.

According to a twelfth aspect of the present invention, the container according to any one of the first to ninth aspects, wherein the base material of the outer material is a biodegradable resin film.

Further, the invention according to claim 13 is the container according to any one of claims 1 to 12, wherein the inner material is made of paper.

According to a fourteenth aspect of the present invention, the inner part is made of paper having a resin layer provided inside.
The container described in (1).

According to a fifteenth aspect, the container according to any one of the first to fourteenth aspects is characterized in that the shape of the container is a cup shape, a tray shape, a bowl shape, or the like.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
First, the inner material and the outer material constituting the container in the present invention are not particularly limited in material and the like, but are preferably made of paper from the viewpoint of processing properties after use. In the internal material, it is also possible to use a resin layer provided by an appropriate method such as film lamination or coating for the purpose of improving the water resistance effect. Similarly, the outer material is not limited to paper, a resin film such as polyethylene, and the like. When a resin film is used, if it is a biodegradable film, the processability after use is improved.

The beads used as the intermediate layer in the present invention have a structure in which a thickener whose binding property is deactivated by hydrolysis is used as a main raw material of a three-dimensional network structure and has voids therein. The present inventors have disclosed in Japanese Patent Application Laid-Open No. 05-27145.
No. 7, JP-A-05-271458, and a method for producing expanded beads proposed by the invention disclosed in Japanese Patent Application Laid-Open No. 05-271458. That is, as pulp containing recycled pulp constituting beads, virgin such as kraft pulp, soda pulp, sulfite pulp, groundwood pulp, ground refined wood pulp, thermomechanical pulp, etc. which are bleached or unbleached using softwood or hardwood Pulp, or recycled pulp derived from waste paper, old corrugated paper, old magazines and the like can be used.

Alternatively, pulp produced in a process such as paper processing or processed into fibrous or floc by an appropriate apparatus can be used. An appropriate amount of a solvent is added to the pulp containing the recycled pulp, and the pulp is suspended and kneaded. The solvent is not particularly limited, but is selected so that the raw material is not affected by aggregation or the like. Specifically, water or alcohols such as ethyl alcohol can be used, and they may be used as a mixture.

Next, a thickener is added thereto and mixed. The amount of addition may be changed according to the added substance or the strength of the pulp foam buffer to be obtained later. As the thickener, those which deactivate the property of binding pulp by hydrolysis are preferable, and those which are biodegradable are more preferable. Specifically, natural polysaccharides such as sodium alginate, starch, agar, and mannan; processed products of natural polysaccharides such as carboxymethyl cellulose; proteins such as gelatin and glue; and synthetic water-soluble polymers such as polyvinyl alcohol. Can be used.

In order to obtain a three-dimensional network structure having a void therein, there are two methods.
One is a method in which a foaming agent is added, formed into granules of a desired size, and then foamed. The other is a method of adding a surfactant, stirring and foaming, and then forming into granules of a desired size.

When a blowing agent is added, the amount of addition is not limited. For 100 parts by weight of pulp, 1
It is preferable to add about 0 to 20 parts by weight, but this can be changed according to the strength. As the foaming agent, specifically, a thermal decomposition type foaming agent is preferably used, and examples thereof include inorganic foaming agents such as sodium bicarbonate and ammonium carbonate, and organic foaming agents such as azodicarbonamide and benzenesulfonyl hydrazide. After mixing with other raw materials, the mixture is molded into granules, heated, dried and foamed to obtain foamed pulp beads.

When a surfactant is added, the addition amount is not particularly limited. 5 to 2 parts per 100 parts by weight of pulp
It is preferable to add 0 parts by weight, but this may also be changed depending on the desired degree of foaming. Specific examples of the surfactant include non-ionic surfactants such as soap (higher fatty acid salt), Tween (trade name, manufactured by Kanto Kagaku Co., Ltd.), and Span (trade name, manufactured by Kanto Kagaku Co., Ltd.). Anionic surfactants, amphoteric surfactants, anionic surfactants such as sulfonated products, cationic surfactants, and the like can be used.

This surfactant is mixed with the above-mentioned pulp suspension, and further vigorously stirred to foam. The rate of foaming by agitation can also be adjusted as desired. The pulp foamed beads are obtained by molding the raw material containing the bubbles into granules and drying by heating. The method for providing the beads as an intermediate layer between the inner and outer substrates is not particularly limited. For example, the inner material is formed in a container shape, the outer material is molded with dimensions that can keep an appropriate distance around it, and either the inner material or the outer material is bent so that the inner material is in contact with the inner material or outer material. A space is created, and beads are blown into the space to fill the space, thereby forming an intermediate layer.

Alternatively, beads may be fixed to at least one of the inner and outer substrates from the viewpoint of improving production efficiency. The method for fixing is also not particularly limited, but after molding the pulp beads, an adhesive solution is applied to the surface of the beads or the contact surface with the beads on either the inner or outer substrate, and the adhesive is cured. A method of binding the beads and the substrate with each other, and a method of previously providing a thermoplastic resin or a mixture of a thermoplastic resin and foamable hollow particles as a coating layer on the pulp bead surface, and using this for bonding. Can be

The adhesive substance to be applied to the surface in the former method is not particularly limited, but includes starch-based sizing agents, water-soluble resins such as polyvinyl alcohol and carboxymethyl cellulose, polyethylene resins, and polyester resins. Solvent-soluble or emulsion-type adhesives mainly composed of a synthetic resin such as an ethylene-vinyl acetate copolymer can be used.

An appropriate amount of the adhesive solution is applied to the surface of the pulp beads or the substrate by spraying or the like, and an appropriate amount of the pulp beads is laminated on the substrate to solidify the adhesive. To make a container.

The latter method includes a method in which a coating layer is provided on the surface of beads and is used for adhesion. The resin to be coated is a thermoplastic resin or a thermoplastic resin and expandable hollow particles. And mixtures thereof. As the thermoplastic resin, polyethylene resin, polyester resin, polyacrylate, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, acrylic resin, polyvinylidene chloride, polyamide such as nylon, polyvinylpyrrolidone, and the like,
In addition, copolymers of these, for example, vinyl acetate-polyethylene copolymers, polyethylene-acrylic acid copolymers and the like can be used, and there is no particular limitation. These may be used alone or as a mixture.

When the expandable particles are used in combination, a thermally expandable microcapsule in which a low boiling point solvent is sealed in a microcapsule can be used as the expandable particle. That is, the polymer in the outer shell is softened by heating and the solvent in the inner shell is gasified, and the volume expands several tens times.

Specifically, as a solvent for the inner shell, an organic solvent such as isobutane, pentane, petroleum ether, hexane or the like is wrapped with a thermoplastic resin such as vinylidene chloride, acrylonitrile, acrylate, methacrylate and the like. Heat-expandable microcapsules can be preferably used. The mixing ratio of the expandable particles to the thermoplastic resin is not particularly limited.

In coating these,
These resins are prepared by dissolving them in a suitable solvent such as water, or by mixing foaming particles into an emulsion or the like, and applying by spraying, spray coating or the like. After the application, it is dried at an appropriate temperature to evaporate the solvent to form a coating layer. The beads prepared in this manner are heated by an appropriate means to melt the thermoplastic resin prepared on the surface of the beads, or simultaneously expand the expandable particles, and then solidify the beads. Are bonded to form a container.

[0034]

As described above, high heat insulating properties can be imparted by laminating beads having voids inside a pulp containing recycled pulp as a main raw material, and the material is mainly composed of pulp. It is possible to provide a new container that has been incinerated.

[0035]

EXAMPLES The present invention will be described below with reference to examples.
It is not limited to the materials used here.

<Example 1> Pulp: Corrugated cardboard ‥‥ 100 parts by weight Thickener: 0.5% by weight sodium alginate solution ‥‥ 2000 parts by weight Surfactant: fatty acid ester (Tween 80 manufactured by Kanto Chemical Co., Ltd.) 5% by weight) After vigorously stirring and foaming, the mixture was molded to a particle size of 5 mm and immersed in a 2% calcium chloride dihydrate solution.
Sodium alginate becomes insoluble calcium alginate, which stabilizes its shape. This is 14
It was dried in an oven at 0 ° C. to obtain expanded pulp beads.
Top opening outside diameter is 90mm, bottom outside diameter is 80mm, height 1
A 50 mm paper container is used as the inner material, and a large outer container made of a paper container having a size of 3 mm is prepared for each part around the container.
The upper end opening was bent toward the inner material side, an intermediate layer portion was provided between the upper material and the inner material, and the beads prepared above were filled therein to obtain a container having a sandwich structure.

Example 2 Pulp: defibrated softwood kraft pulp ‥‥ 100 parts by weight Thickener: polyvinyl alcohol (completely saponified, degree of polymerization: about 2400) 5% aqueous solution ‥‥ 1000 parts by weight Blowing agent: azo Dicarbonamide ‥‥ 20 parts by weight After well mixing and forming a slurry, forming into a granule of about 4 mm, throwing it into an oven at 180 ° C., heating, foaming the foaming agent, and further drying to obtain foamed beads .
Ethylene-vinyl acetate copolymer emulsion 10
% Solution is sprayed on the beads, and the outer diameter of the upper end opening is 90 m.
The beads were adhered to a paper container having a diameter of 80 mm, a bottom outer diameter of 80 mm, and a height of 150 mm, and coated cardboard was wound therearound as an outer layer and solidified to obtain a container.

Example 3 The pulp beads obtained in Example 1 were sprayed with a thermoplastic resin: emulsified polyethylene (Zyxen A, manufactured by Sumitomo Seika Co., Ltd.) 25% solid content solution 100 parts by weight. The spray amount was adjusted so that the solid content of the mixture was 7.5 g per liter of pulp beads. This was pre-dried at 80 ° C., then filled between the paper container used in Example 2 and the outer layer of coated cardboard, and heated in an oven at 140 ° C. to soften the resin on the bead surface. Thereafter, it was taken out of the oven and cooled, and the resin was solidified to bind the beads to the container and the paper of the outer layer to obtain a container.

Example 4 To the pulp beads obtained in Example 1, thermoplastic resin: emulsified polyethylene (Zyxen A manufactured by Sumitomo Seika Co., Ltd.) 25% solid content solution 100 parts by weight Expandable particles : 35 parts by weight of heat-expandable microcapsules (Microsphere F1400, manufactured by Matsumoto Yushi Co., Ltd., solid content: 70%) were sprayed. The spray amount is pulp beads 1
The mixture was adjusted so that the solid content of the mixture was 7.5 g per liter. After pre-drying this at 80 ° C.,
Was filled between the paper container used in the above and the coated paperboard of the outer layer, and heated together with the mold in a 140 ° C. oven to soften the resin on the bead surface and expand the expandable particles. Thereafter, the resin was taken out of the oven and cooled, and the resin was solidified to bind the beads to the inner layer container and the outer layer paper to obtain a container.

<Example 5> The obtained inner surface of the inner layer container prepared in the same manner as in Example 4 was spray-impregnated with wax, dried by heating and coated with wax, and then the same operation as in Example 4 was performed. Obtained as a container.

<Embodiment 6> A fan-shaped cutout thickness 20 to fit around the container prepared as the inner layer of Embodiment 1.
A bead sprayed with an adhesive is laminated on a micron polyethylene film in the same manner as in Example 1, and further wound around the same container as in Example 1, the adhesive is solidified, and the beads, the inner container and the outer film are formed. It was fixed and obtained as a container.

<Comparative Example> As Comparative Example 1, a paper cup impregnated with wax and a container molded with polystyrene paper as Comparative Example 2 were prepared in the same shape as in Examples 1 to 6, and their functions were compared.

For comparison, a bag made of a nylon / polyethylene laminated film was filled with 500 ml of hot water at 90 ° C., and this was filled into the containers of Examples 1 to 6 and Comparative Examples 1 and 2.
And the heat outside the containers was compared after 5 minutes. The calories burned were compared, and the results were comprehensively evaluated.

[0044]

[Table 1]

As described above, the present invention (Examples 1 to 6) was excellent in overall evaluation because of low heat insulation and low calorie burnability as a treatment property after use. Comparative Example 1 was inferior in heat insulation properties, and Comparative Example 2 was excellent in heat insulation properties, but had high calorie burned, resulting in slightly inferior overall evaluation.

[0046]

According to the present invention, a bead having a structure having voids therein is used as a main material of a three-dimensional network structure using a thickener which is deactivated by hydrolysis with pulp as a main raw material. This is a container provided in the intermediate layer, and the beads have the above-mentioned structure, so that the heat insulating effect is excellent. Furthermore, by adjusting the addition amount of the foaming agent and the thickener, it is possible to adjust the bead density, and it is possible to give a range to the heat insulating effect and the strength. In addition, since these beads are mainly made of pulp, they do not increase the heat of combustion, and have high processability after use such as early decomposition even when landfilling is performed.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3E086 AA22 AD05 AD06 BA14 BA16 BA29 BB90 CA01 4F100 AJ04A AK01A AK01B AK01C BA03 BA07 BA10B BA10C CA01A CA16A CA18A CB00 DE01A DG10B DG10C DJ05A GB16 J02A02A

Claims (15)

[Claims] 1. A container having a cylindrical portion and a bottom portion having an open upper end, comprising a sandwich-structured material having an intermediate layer between both inner and outer base materials, the intermediate layer comprising pulp containing recycled pulp. It is composed of beads containing voids as the main raw material of the three-dimensional network structure with a thickener whose binding property is deactivated by hydrolysis, and has high heat insulation properties and easy processing properties. Characteristic container. 2. The container according to claim 1, wherein the thickener constituting the beads of the intermediate layer is biodegradable. 3. The container according to claim 1, wherein voids inside the beads of the intermediate layer are bubbles derived from a decomposable foaming agent. 4. The container according to claim 1, wherein voids inside the beads of the intermediate layer are bubbles derived from a surfactant. 5. A bead is filled in a space defined by an inner material and an outer material.
Or the container according to 3. 6. The container according to claim 1, wherein the beads of the intermediate layer are fixed to at least one of the inner and outer base materials. 7. The intermediate layer beads intervening an adhesive substance,
7. The container according to claim 6, wherein the container is configured by being combined with a base material of an inner material or an outer material. 8. The bead of the intermediate layer is a bead having a thermoplastic resin layer provided on its surface, and is constituted by being bonded to a base material through the thermoplastic resin layer.
A container according to claim 1. 9. The beads of the intermediate layer are beads provided with a thermoplastic resin layer containing expandable hollow particles on the surface, and are formed by bonding to a base material through the thermoplastic resin layer. 9. The container according to claim 8, wherein: 10. The container according to claim 1, wherein the base material of the external material is paper. 11. The container according to claim 1, wherein the base material of the external material is a resin film. 12. The container according to claim 1, wherein the base material of the external material is a biodegradable resin film. 13. The container according to claim 1, wherein the inner material is made of paper. 14. The container according to claim 13, wherein the inside is made of paper having a resin layer provided inside. 15. A container having a cup shape, a tray shape,
The container according to any one of claims 1 to 14, wherein the container has a bowl shape or the like.