JPH10230923A - Compound container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make injected resin easily separable from a blank board and enable reduction of volume and recycling of resources after use for a compound container that is made up by a method wherein a laminated blank board is arranged in a form of container to be molded in dies for injection molding, thermoplastic resin is injected into the dies to fill a cavity formed by the blank, and both ends of the blank are joined together. SOLUTION: In a compound container P, having at least a side wall and a bottom, made up by injecting thermoplastic resin into a cavity in which a blank board made of laminated material including paper is arranged beforehand and by integrating the blank board with a resin-molded part 2 formed of the thermoplastic resin, a layer becoming the internal surface when formed into the container of the blank is constructed of an alkali soluble resin layer 11A and the thermoplastic resin is made of resin sticking by heat seal to the blank board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A blank plate made of a laminate mainly composed of paper is placed in an injection molding die, and a thermoplastic resin is injected into the die and integrated with the blank plate. It relates to the composite container formed.

[0002]

2. Description of the Related Art Conventionally, as a material of a rigid container, a plastic injection-molded product has been used together with glass, metal and the like. Containers made of plastic by injection molding are widely used because they are lighter in weight than the above-mentioned glass and metal, can be incinerated after use, and moreover, they are inexpensive if mass-produced. However, the injection container made of a single plastic may not have sufficient oxygen barrier properties necessary for protecting the contents. Furthermore, after being used as a container, in waste disposal, for example,
When a large amount of plastic containers are incinerated, there are problems such as damage to the incinerator due to high calorie burned. Therefore, a laminate having a thickness corresponding to the required container side wall thickness is punched into a blank plate in a mold for molding by injection of plastic, and inserted into a mold for injection molding. By injecting thermoplastic resin into the mold,
A method has been used in which the blank plate and the injected resin are heat-sealed in a mold to form a composite container. However, the resin constituting the inner surface layer of the injection resin and the blank plate to which the injection resin is thermally fused is, for example, a polyolefin resin, or a polycarbonate resin, a polyester resin, a polyamide resin, or the like, and the fusion is strong. Yes,
Although the physical strength of the container is preferable, it is almost impossible to separate the blank plate and the resin molded part for the purpose of recovering each material after use. For this reason, the used composite container is discharged as waste in bulk as it is, and the efficiency in the transport or processing plant is reduced. Furthermore, it is not possible to recover each material and it is not a preferable container from the viewpoint of effective utilization of resources. In order for the packaging containers to fulfill their function and to be reused as a material without being landfilled or incinerated as waste, it must be sorted out as a single material, but packaging containers that can be easily separated by material Appearance was desired.

[0003]

The laminated blank plate is disposed in a mold for injection molding so as to have a container shape.
Injecting a thermoplastic resin into the mold to form a gap between the blanks, and in a composite container formed by joining the blank ends, separation of the blank plate and the injection resin is performed. It facilitates volume reduction and resource recovery after use as a container.

[0004]

Means for Solving the Problems A thermoplastic resin is injected into a cavity in which a blank plate made of a material having a laminated structure including paper is provided in advance, and a resin formed by the blank plate and the thermoplastic resin is formed. In a composite container having at least a side wall portion and a bottom portion obtained by integrating the part, the blank plate is a composite container in which a layer serving as an inner surface when molded into a container is formed of an alkali-soluble resin layer, The thermoplastic resin is a resin that can be thermally fused to the blank plate.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a blank having a thickness and rigidity which can be formed into a side wall and / or a bottom wall of a container, which is formed of a laminate including an alkali-soluble resin layer, in an injection mold. After the mold is disposed and clamped in a substantially container shape, an alkali-soluble thermoplastic resin or a polyolefin-based resin is injected and injected to form a gap or a flange portion of the blank plate and the end of the blank. These are joined together to form a container. FIG.
Are perspective views (a) showing an embodiment of the composite container of the present invention, X
₁ -X ₁ part cross-sectional view (b), FIG. 2, showing the plane of the front of the blank plate to be molded in FIG. 1 container (a), perspective view of a molded resin portion excluding the blank plate from FIGS. 1 (a) (B), FIG.
FIG. 4 is a plan view of the case where the heat-sealing layer is provided on the entire inner surface of the blank plate (a) and the case where the heat-sealing layer is provided partially (b) as viewed from the inner surface side.
Is X ₂ -X ₂ in FIG. 3 (a), cross-sectional view of the X ₃ -X ₃ (b), cross-sectional view showing the heat-sealing portions of the blank plate and the injected resin (c), FIG. 5, Example FIGS. 1 to 6 are cross-sectional views showing material configurations of blank plates used in Comparative Examples 1 to 3. FIG.
It is sectional drawing which shows the material structure of the blank board used for 1-13 and Comparative Examples 11-13. The composite container in the present invention refers to the side wall member 20 and / or the bottom member 21 of the container body.
As a blank plate 1 and then placed in a mold of an injection molding machine,
This is a container formed by injecting a thermoplastic resin into the mold and forming the resin molded portion 2 of the thermoplastic resin and simultaneously thermally fusing the blank plate 1. The composite container P of the present invention can also be formed in the formation of a lid, and when the lid is formed, the top plate member and the skirt portion hanging from the peripheral edge of the top plate are formed as blank plates. It can be molded in the same way as the body.

The blank plate 1, which is a main component of the composite container P of the present invention, has a desired period of maintaining the type, content and good quality of the contents to be filled when used as a container. The configuration is designed according to the processing performed or the distribution format. As a component of the blank board, paperboard is mainly used as a support. The reason is that paperboard has stiffness, smoothness, printability, etc., and the calorie burned after incineration after use as a container is lower than that of polyolefin plastic. It is most suitable as a blank plate material. A specific paper thickness (or basis weight) used in the present invention is 100 to 500 g / m ² . The decoration of the side wall and the like of the composite container may be performed on the front surface or the back surface of the paperboard or the material laminated on the surface of the paperboard in the step of laminating the blank board. In any case, since the decoration is performed in a flat stage, there is less restriction compared to decoration or the like by printing on a normal three-dimensional molded product, and the feature is that the efficiency and quality are good.

The blank 1 constitutes the main area of the wall of the composite container. Therefore, various kinds of materials can be laminated in order to block water vapor, oxygen, light, etc., which affect the deterioration of the contents. Also, in the injection mold,
When the injection resin is in a molten state, the container is formed by melting and bonding with the thermoplastic resin laminated on the inner surface or the outer surface of the blank, so that any surface of the blank plate 1, preferably, A layer made of a material fusible with the injection-molded resin is provided on a surface which becomes an inner surface when molded into a container. As described above, the composite container of the present invention is obtained by laminating an alkali-soluble resin as a component of the blank plate 1. That is, in the present invention, the alkali-soluble resin is provided on the inner surface of the blank plate 1 (the side that becomes the inner surface when molded as a composite container, the same applies hereinafter).
In the present invention, an alkali-soluble thermoplastic resin is laminated on the blank plate 1 as a predetermined layer of the blank plate 1 using an extrusion lamination method or an emulsion or solution of an alkali-soluble resin by a coating method.

[0008] The alkali-soluble thermoplastic resin used in the present invention is not particularly limited as long as it is soluble in an aqueous alkali solution. Further, as a specific example of the resin when provided by the extrusion laminating method, acrylic acid, ethylene-acrylic acid copolymer, acrylate resin, acrylate-acrylic acid copolymer and the like are suitable for extrusion. There are certain things. Also,
When an alkali-soluble resin layer is provided on the inner surface of the blank plate 1 by a coating method, a styrene-acrylic acid copolymer resin, an acrylate resin, an acrylate-acrylic acid copolymer resin, an acryl-vinyl acetate resin may be used. An ordinary method of coating and drying an organic solvent solution or an aqueous dispersion of a mixed resin containing a polymer resin, a polyacrylamide resin, or the like can be used. The alkali-soluble thermoplastic resin used in the present invention preferably has an acid value of 100 mgKOH / g to 500 mgKOH / g. Acid value 100mgK
If it is less than OH / g, dissolution becomes slow and peeling becomes difficult. Further, when the acid value exceeds 500 mgKOH / g, the resin may be decomposed when the resin is melted during molding, or corrosion may occur in a processing machine. The alkali-soluble resin is a resin having a property of dissolving only when immersed in an aqueous alkali solution, and does not dissolve even when immersed in acidic water or neutral water. That is, under normal use conditions, by disposing a substance that is dissolved only in an alkaline aqueous solution without dissolving on the inner surface, the container after use is immersed in the alkaline aqueous solution, and The inner surface dissolves, and as a result, the resin molded portion 2 of the composite container separates from the blank plate 1.

When the alkali-soluble thermoplastic resin is provided by an extrusion lamination method, about 195
The substrate may be heated to a temperature of up to 200 ° C. (the resin may be decomposed if the heating temperature of the resin exceeds 200 ° C.), and may be directly laminated on the base material constituting the blank plate 1 or may be formed into another film. A film, which has been previously formed by a machine, for example, a T-die film forming machine or an inflation machine, is dry-laminated with a general laminating machine to a base material constituting the blank plate 1 using a urethane-based adhesive or the like. Or
The adhesive resin may be provided while being laminated while being melt-extruded, that is, a so-called sandwich laminate.

The injection resin used in the present invention needs to be a resin that can be thermally fused to a layer provided on the inner surface of the blank plate 1 used. Therefore,
The inner surface of the blank plate 1 has an alkali-soluble resin layer 11A
In the case of the laminated body made only of the above, it is preferable that the injection resin is an alkali-soluble resin, that is, it is preferable that the injection resin be the same material as the alkali-soluble resin used for the inner surface layer 11A of the blank plate 1. The alkali-soluble resin as the injection resin is bonded to the alkali-soluble resin layer 11A of the inner surface layer of the blank plate 1 by heat fusion by heat at the time of injection molding, and is immersed in an alkaline aqueous solution after use as a composite container. At this time, the inner surface layer 11A and the resin molding portion 2 of the blank plate 1 are dissolved in an alkaline aqueous solution, so that the blank plate 1 is collected in a flat state.

In the present invention, it is possible to inject a resin other than the alkali-soluble thermoplastic resin. It is sufficient that a resin which can be directly bonded to the blank plate 1 provided with the alkali-soluble thermoplastic resin by heat at the time of injection molding exists. For example, another heat is applied to the alkali-soluble thermoplastic resin layer on the inner surface of the blank plate 1. It has been found that by providing the fusion layer 11N, the possibility of selecting an injection resin is widened. On the further inner surface of the alkali-soluble thermoplastic resin provided on the inner surface of the blank plate 1, for example, a layer 11N made of a material which is not alkali-soluble but can be heat-fused with a polyolefin resin.
By using a polyolefin-based resin as the injection resin to form a composite container in the same manner as described above, while the resin molded portion 2 is a polyolefin-based resin, the resin molded portion 2 is immersed in a predetermined concentration of an alkaline aqueous solution to form a blank. It has been found that a composite container P in which the plate 1 and the resin molded part 2 can be easily separated can be obtained. For forming the heat-sealing layer 11N, for example, an adhesive (hereinafter referred to as EVA) containing an ethylene-vinyl acetate copolymer as a main component of the vehicle can be used. The blank plate 1 provided with the heat-sealing layer 11N of EVA on the inner surface of the blank plate 1 is disposed in an injection molding cavity, and a polyolefin-based resin is injected. Container P
Could be obtained. It was confirmed that the blank plate 1 and the resin molded part 2 could be separated by immersing the composite container P in an aqueous alkali solution after using it as a container. That is, the heat sealing layer 11N can be laminated on the alkali-soluble resin layer provided on the inner surface of the blank plate 1, and can be heat-sealed with an injection molding resin other than the alkali-soluble resin. The heat-sealing layer 11N may be provided on the entire inner surface of the blank plate 1, but as a main object of the present invention, an implementation method that does not hinder the dissolution rate in an alkaline aqueous solution or the like is shown in FIG. As shown in FIG. 4B, it is desirable to apply the coating only to a portion corresponding to a portion where the injection resin is thermally fused. As shown in FIG. 4 (c), the joint portion between the blank plate 1 and the resin molded portion formed by the partially coated blank plate is in a state where the alkali-soluble resin layer 11A is exposed except for the joint portion. Does not hinder dissolution when immersed in an aqueous solution. Thermal fusion layer 11
As N, for example, a solution of EVA is applied to the entire surface of the alkali-soluble resin layer on the inner surface of the blank plate 1 by roll coating, and a polyolefin-based resin, preferably polyethylene, polystyrene, polypropylene, or the like is used as an injection resin to form a composite container. . Further, as described above, the heat-sealing layer 11
In the case where N is partially provided, the heat-sealing layer 11N
May be provided. In addition, the above-mentioned E
VA, and a polyolefin-based resin was exemplified as the injection resin.
If the same peeling can be performed between the heat sealing layer 11N and the injection molding resin, another resin combination may be used.

When the composite container P obtained when the injection resin is a polyolefin resin is immersed in an alkaline aqueous solution, the heat-sealing layer 11N of the blank plate 1 and the injection resin are recovered in a three-dimensional state without being dissolved. However, since the alkali-soluble resin layer 11A provided on the blank plate 1 is dissolved, the blank plate 1 is recovered in a flat state.

In the blank plate 1 used in the present invention, an outer surface of a paper 10 as a support (hereinafter referred to as an outer surface when formed into a container, the same applies hereinafter) is provided with water resistance, friction resistance or gloss. For this purpose, an outer layer 14 made of a plastic such as aluminum foil, polyethylene, polypropylene, polyester, or polyurethane may be provided.
Further, as described above, various layers of metal foil, a single layer, a film provided with a barrier layer, or the like can be laminated on paper as a base material in order to prevent and protect the contents from being deteriorated. Middle layer 1
The method of laminating 3 as a configuration of the blank plate 1 can be performed using a normal laminating method. For example, a method such as a sandwich lamination method in which an adhesive resin is melt-extruded and two kinds of materials are bonded to each other, a dry lamination method using a urethane-based adhesive, or the like can be used. As the intermediate layer 13, a barrier layer 13b may be provided on an aluminum foil, various plastic films, or a plastic film. As the barrier layer 13b, a layer on which polyvinylidene chloride is applied, or a film on which aluminum, silica, alumina, or the like is deposited may be laminated. In addition, as the ceramics such as silica and alumina, metal oxides such as indium tin oxide (ITO), zinc, tin, titanium, zirconium, vanadium, barium, and chromium, silicon nitride, and silicon oxide can be used. The thickness of these ceramic vapor-deposited layers is preferably set in the range of 50 to 1000 °, more preferably 100 to 1000 °.

After the composite container P according to the present invention has been used as a container, the composite container P is immersed in a predetermined alkaline aqueous solution to dissolve the alkali-soluble thermoplastic resin component provided as a component of the container. The plate 1 and the resin molded part 2 may be separated, or the resin molded part 2 itself may be dissolved. By controlling the temperature and time of the dissolution, the resin molded part 2 is not completely dissolved, and the dissolution is stopped by washing or neutralization at a stage where the resin molded part 2 is separated from the blank plate 1, and the resin molded part 2 remains as a molded body. It is also possible to collect.

The separated blank plate 1 is flat at the time of molding, and returns to a flat state by this separation. At the same time, the separated resin molded portion is a single plastic and is cut or heated and pressed. Both are reduced in volume.

The inner surface layer 11A and the resin molding portion 2 of the blank plate 1 made of the alkali-soluble resin laminated on the composite container P of the present invention are not dissolved under ordinary use conditions, and the used container is removed from the alkali container. By immersing in the aqueous solution, the alkali-soluble resin is dissolved, and as a result, the resin molded portion 2 of the composite container P is separated from the blank plate 1. Further, when dissolving the composite container P of the present invention in an alkaline aqueous solution, the dissolution rate depends on the concentration and the liquid temperature of the alkaline aqueous solution. The concentration of the aqueous alkali solution is preferably, for example, about 1 to 3% by weight with NaOH. As for the liquid temperature, the higher the temperature, the faster the dissolution. Therefore, as an actual work for separating and collecting waste by material, efficiency can be examined by setting temperature conditions and the like. In addition, stirring the aqueous alkali solution also has an effect on accelerating dissolution.

As described above, the composite container P of the present invention
Shows the effect that handling and processing after use can be facilitated. That is, when the used container is immersed in an alkaline aqueous solution, a part of the material constituting the container is dissolved, so that the blank plate 1 and the resin molded portion 2 constituting the composite container P are separated. To separate. As a result, the blank plate 1 as a component of the composite container P
Returns to a flat state before being placed in a mold for molding, and when the resin molded part 2 is an alkali-soluble thermoplastic resin, it is recovered in a state of being dissolved in an aqueous alkaline solution. Alternatively, a blank plate 1
May be taken out of the aqueous solution at the stage of separation, and may be recovered in a form in which the whole is not dissolved by washing with water, that is, in a three-dimensional structure in which the blank plate 1 is removed from the composite container. When the resin molded part 2 is made of a material other than the alkali-soluble resin, for example, a polyolefin resin, the immersion in an aqueous alkali solution causes the heat-sealing layer 1 of the blank plate 1 to be removed.
Since only the alkali-soluble resin inside 1N dissolves,
The blank plate 1 can be recovered in a flat state similarly to the above, and the polyolefin resin and the like constituting the heat-sealing layer 11N and the resin molded portion 2 can be collected in a three-dimensional structure. When the alkali-soluble thermoplastic resin and the polyolefin-based resin are recovered in a three-dimensional structure, they can be mechanically crushed to reduce the volume, or can be melted by heat and re-formed into resin pellets. It can be used as a recycled material. The possibility of recovery of each material from the recovered blank plate 1 depends on the type of paper and other laminated materials, but in any case, since the volume can be completely reduced, including transportation and storage, etc. The handling efficiency is very good.

[0018]

Next, the present invention will be described more specifically with reference to the following examples. Examples 1 to 6 and Comparative Examples 1 to 3 are examples in which an alkali-soluble thermoplastic resin (comparative example is another resin) of the inner surface layer of the blank plate 1 was provided by an extrusion laminating method. Comparative Example 1
Nos. 1 to 13 were provided with an alkali-soluble resin (a heat-sealing layer in Comparative Example) by a coating method. In all of the examples and comparative examples, the container shape was unified into a round cup type. In order to improve the adhesion between the coated surface and the extruded resin at the time of extrusion lamination at the stage of laminating the blank plate 1, although not shown in the drawings and the like, an anchor coating agent may be applied.

Example 1 A substrate 10 having a basis weight of 230 g / m ^{2 was used.}
And a low-density polyethylene resin was extrusion-laminated on the outer surface layer 14 of the acid-resistant paper to form a thermoplastic resin layer having a thickness of 15 μm, thereby forming a two-layer laminate. Next, an acid value of 120 mg was applied to one surface of the two-layer laminate where the acid-resistant paper was exposed.
KOH / g of an alkali-soluble thermoplastic resin was extrusion-laminated to form an inner surface layer 11A having a thickness of 40 μm, thereby forming a three-layer laminate. Further, this laminate is punched into a shape as shown in FIG.
And [FIG. 5 (a)] After disposing the blank plate 1 in the cavity of the injection mold, injection molding is performed using an alkali-soluble resin (description of material) having an acid value of 120 mg KOH / g. A round cup-shaped composite container having an inner volume of 220 cc as shown in a) was prepared.

Example 2 The substrate 10 had a basis weight of 230 g / m ^2.
And a low-density polyethylene resin was extrusion-laminated on the outer surface layer 14 of the acid-resistant paper to form a thermoplastic resin layer having a thickness of 15 μm, thereby forming a two-layer laminate. An alkali-soluble thermoplastic resin having an acid value of 120 mg KOH / g is applied to a biaxially stretched polyester film (thickness: 12 μm) having a silicon oxide (SiO ₂ ) deposited film (thickness: 50 nm) as a barrier layer 13 b. , A 50-μm-thick extruded film produced by inflation was used as the inner surface layer 11A, and a urethane-based adhesive as the adhesive layer 12 was dry-laminated to form a three-layer laminate. Next, an adhesive layer 12 is provided on the surface of the two-layer laminate where the acid-resistant paper is exposed.
Ethylene-methacrylic acid copolymer (EMAA)
While extruding with a thickness of 15 μm, the silicon oxide (SiO ₂ ) -deposited film side of the above three-layer laminate was bonded to form a laminate.
[FIG. 5 (b)] Hereinafter, a round cup-shaped composite container was prepared in the same manner as in Example 1.

Example 3 An acid value of 120 mg KO was used for a biaxially stretched polyester film (12 μm thick) as a support.
An extruded film having a thickness of 50 μm produced by forming an H / g alkali-soluble thermoplastic resin into a film by an inflation method is formed as the inner surface layer 11A, and a urethane-based adhesive is formed as the adhesive layer 12 by dry lamination. A laminate was made. [FIG. 5 (c)] Hereinafter, a round cup-shaped composite container was prepared in the same manner as in Example 1.

Example 4 The substrate 10 had a basis weight of 230 g / m ^2.
And a low-density polyethylene resin was extrusion-laminated as an outer layer of the acid-resistant paper to form a thermoplastic resin layer having a thickness of 15 μm, thereby forming a two-layer laminate. Next, an acid value of 120 mg KO was applied to the surface of the two-layer laminate where the acid-resistant paper was exposed.
An H / g alkali-soluble thermoplastic resin was extrusion-laminated to form an inner surface layer 11A having a thickness of 40 μm, thereby forming a three-layer laminate. As shown in FIG. 3B, a heat-sealing layer 11N containing EVA as a main component of the vehicle was partially provided on the inner surface layer 11A of this three-layer laminate by a coating method. [FIG.
(D) Next, the laminate was punched into a shape as shown in the figure to obtain a one-piece type blank plate 1. Then, after disposing the blank plate 1 in the cavity of the injection mold, injection molding was performed using a polypropylene resin as a polyolefin-based resin, and a round cup-shaped composite container was prepared as in Example 1. .

Example 5 The substrate 10 has a basis weight of 230 g / m ^2.
And a low-density polyethylene resin was extrusion-laminated as an outer layer 14 on the acid-resistant paper to form a thermoplastic resin layer having a thickness of 15 μm, thereby forming a two-layer laminate. Also,
An alkali-soluble thermoplastic resin having an acid value of 120 mg KOH / g was extrusion-laminated on a biaxially stretched polyester film (thickness: 12 μm) having a silicon oxide (SiO ₂ ) deposited film (thickness: 50 nm) as a barrier layer 13b. After forming the inner surface layer 11A having a thickness of 40 μm, a heat-sealing layer 11N containing EVA resin as a main component of the vehicle was partially provided to form a four-layer laminate.
Next, on the surface of the two-layer laminate where the acid-resistant paper is exposed,
An ethylene-methacrylic acid copolymer (E
While extruding MAA) to a thickness of 15 μm, the silicon oxide (SiO ₂ ) -deposited film side of the four-layer laminate was bonded to form a laminate. [FIG. 5 (d)] Hereinafter, a round cup-shaped composite container was prepared in the same manner as in Example 4.

Example 6 An alkali-soluble thermoplastic resin layer having an acid value of 120 mg KOH / g was extrusion-laminated on a biaxially stretched polyester film (thickness: 12 μm) as a support to form an inner surface layer 11A having a thickness of 40 μm. Thereafter, a heat-sealing layer 11N containing EVA as a main component of the vehicle was partially provided to form a three-layer laminate. [FIG. 5 (f)] Hereinafter, a round cup-shaped composite container was prepared in the same manner as in Example 4.

[Comparative Example 1] As a comparison with the above-mentioned Example 1,
An inner surface layer 11N made of EVA is provided on the blank plate 1.
[FIG. 5 (g)] In addition, instead of the alkali-soluble thermoplastic resin injected as the resin molded part 2, injection molding was performed using polypropylene as a polyolefin-based resin to produce a similar round cup-shaped composite container. .

[Comparative Example 2] As a comparison with the above-mentioned Example 2,
An inner surface layer 11N made of EVA is provided on the blank plate 1.
[FIG. 5 (h)] In addition, instead of the alkali-soluble thermoplastic resin injected as the resin molded part 2, injection molding was performed using a polypropylene resin to prepare a similar round cup-shaped composite container.

Comparative Example 3 As a comparison with the above-mentioned Example 3,
An inner surface layer 11N made of EVA is provided on the blank plate 1.
[FIG. 5 (h)] In addition, instead of the alkali-soluble thermoplastic resin injected as the resin molded part 2, injection molding was performed using a polypropylene resin to prepare a similar round cup-shaped composite container.

Example 11 The substrate 10 has a basis weight of 230 g / m
The acid-resistant paper of No. ² was used, and a low-density polyethylene resin was extrusion-laminated as the outer layer 14 on the acid-resistant paper to form a thermoplastic resin layer having a thickness of 15 μm, thereby forming a two-layer laminate. Next, an alkali-soluble acryl copolymer emulsion having an acid value of 110 mgKOH / g was coated as an inner surface layer 11A on the surface of the two-layer laminate where the acid-resistant paper was exposed, to prepare a three-layer laminate. On one side of the three-layer laminate where the alkali-soluble emulsion was exposed, a heat-sealing layer 11N containing EVA as a main component of the vehicle was provided. Next, the laminated body was punched into a shape as shown in FIG. [FIG. 6 (a)]
Further, after disposing the blank plate 1 in the cavity of the injection mold, injection molding is performed using a polypropylene resin as the resin molding portion 2 to form a round shape having an inner volume of 220 cc as shown in FIG. Was obtained.

Example 12 The substrate 10 had a basis weight of 230 g / m.
The acid-resistant paper ² was extrusion-laminated with a low-density polyethylene resin on the acid-resistant paper to form a 15 μm-thick outer surface layer 14 to form a two-layer laminate. Further, a biaxially stretched polyester film (thickness: 12 μm) having a deposited film (thickness: 50 nm) of silicon oxide (SiO ₂ ) as a barrier layer 13b 13
And an inner layer 11A coated with an alkali-soluble acrylic copolymer emulsion having an acid value of 110 mg KOH / g.
After 1A, inner layer 11N containing EVA as a main component of vehicle
Was provided to form a four-layer laminate. Next, an ethylene-methacrylic acid copolymer (EMA) was formed as an adhesive layer 12 on one side of the two-layer laminate where the base material 10 (acid-resistant paper) was exposed.
While extruding A) to a thickness of 15 μm, the silicon oxide (SiO ₂ ) -deposited film side of the above four-layer laminate was bonded to form a laminate. [FIG. 6 (b)] Further, after disposing the blank plate 1 in the cavity of the injection mold, injection molding is performed using a polypropylene resin as the resin molding portion 2, as shown in FIG. 1 (a). A round composite container having an internal volume of 220 cc was obtained.

Example 13 A biaxially stretched polyester film (12 μm thick) as a support was coated with an alkali-soluble acrylic copolymer emulsion having an acid value of 110 mg KOH / g as an inner surface layer 11A. A three-layer laminate was prepared by providing a heat-sealing layer 11N as a main component. [FIG. 6 (c)] Furthermore, after disposing the blank plate 1 in the cavity of the injection mold, injection molding is performed using a polypropylene resin as a resin molding portion, as shown in FIG. 1 (a). Inner volume
A round composite container of 220 cc was obtained.

[Comparative Example 11] As a comparison with Example 11, a two-layer laminate was prepared in which the layer formed of the alkali-soluble acrylic copolymer emulsion used for the blank plate 1 was removed. [FIG. 6 (d)] Hereinafter, a round composite container was prepared in the same manner as in Example 11.

[Comparative Example 12] As a comparison with the above-mentioned Example 12, a three-layer laminate was prepared by removing the layer formed of the alkali-soluble acrylic copolymer emulsion used for the blank plate 1. [FIG. 6 (e)] Thereafter, a round composite container was prepared in the same manner as in Example 12.

Comparative Example 13 As a comparison with Example 13, a two-layer laminate was prepared in which the layer formed of the alkali-soluble acrylic copolymer emulsion used for the blank plate 1 was removed. [FIG. 6 (f)] Hereinafter, a round composite container was prepared in the same manner as in Example 13.

[Experimental Examples] The above Examples 1 to 6, 11 to 11
13 and the containers produced in Comparative Examples 1 to 3 and 11 to 13 were immersed in a 3.0% NaOH aqueous solution at 60 ° C. and stirred with a stirring rotor (with blades, 30 times / min). At that time, the time when the blank plate 1 and the resin molded part 2 were separated and the solubility were tested. The results are shown in Table-1 and Table-2. In the present embodiment, the dissolution was performed under the conditions of the above-mentioned solution temperature and the acid value of the alkaline solution.However, the dissolution rate was adjusted by changing the solution temperature or changing the stirring conditions of the immersed solution. It is possible.

[0035]

The composite container of the present invention is a container having excellent protection of contents and rigidity because a barrier film or the like can be laminated on the structure of the blank plate 1. In addition, since printing or the like can be performed on the side wall portion in a flat state before and after the laminating step of the blank plate 1, a container with high quality decoration can be obtained. Then, as a composition of the material, a blank container 1 having at least an inner surface made of an alkali-soluble resin is disposed in an injection mold, and a composite container obtained by injection-injecting the alkali-soluble resin into the mold is provided. Thereby, the container after use is immersed in an aqueous alkali solution, and the alkali-soluble thermoplastic resin layer of the blank plate 1 is dissolved, whereby the three-dimensionality of the shape of the container is lost.
The blank plate 1 has a flat shape. Therefore, since the volume of the used container can be reduced, the space can be saved and the transportation to a waste disposal site or a recycling work site can be efficiently performed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a composite container of the present invention (a), and a cross-sectional view of a part X ₁ -X ₁ (b).

FIG. 2 is a plan view (a) of a blank plate before being formed into a container in FIG. 1; and a perspective view (b) showing a resin molding portion in which the blank plate is removed from FIG. 1 (a).

FIG. 3 is a plan view of the case where a heat sealing layer is provided on the entire inner surface of the blank plate (a) and the case where the heat sealing layer is partially provided (b) as viewed from the inner surface side;

FIG. 4 is a cross-sectional view taken along lines X ₂ -X ₂ (a) and X ₃ -X ₃ (b) of FIG. ₃ , and a cross-sectional view (c) showing a heat-sealed portion between a blank plate and an injection resin.

FIG. 5 is a cross-sectional view showing a material configuration of a blank plate used in Examples 1 to 6 and Comparative Examples 1 to 3.

FIG. 6 is a cross-sectional view showing a material configuration of a blank plate used in Examples 11 to 13 and Comparative Examples 11 to 13.

[Explanation of symbols]

 P Composite container 1 Blank plate 2 Injection resin or resin molded part 10 Base material 11A Inner surface layer (alkali-soluble resin layer) 11N Inner surface layer (heat fusion layer) 12 Adhesive layer 13 Intermediate layer 13b Barrier layer provided in intermediate layer 14 Outer surface layer 20 Side wall member 21 Bottom member

Claims (2)

[Claims] 1. A resin molded portion formed by injecting a thermoplastic resin into a cavity in which a blank plate made of a material of a laminated structure including paper is provided in advance and forming the blank plate and the thermoplastic resin. A composite container having at least a side wall portion and a bottom portion obtained by integrally forming a composite container, wherein a layer which becomes an inner surface of the blank plate when molded into a container is formed of an alkali-soluble resin layer. 2. The composite container according to claim 1, wherein the thermoplastic resin is a resin that can be thermally fused to the blank plate.