JP2000079937A - Sealed complex tray container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate any poor seal problem caused by a lid member by a method wherein a plastic sheet laminated on and adhered to an upper surface of each of the flange plates of a paper tray container is made flat and a groove of the plastic sheet is not formed at an abutting line where ends of each of the flange plates are abutted to each other. SOLUTION: In the case that a plastic sheet (sheet) 25 is laminated on and adhered to both an inner surface of a paper tray container 22 and an upper surface of each of the flange plates, a pressing member 29 is arranged on the sheet 25 overlapped on the upper surface of each of the flange plates, and under this state, compressed air is blown onto the heated and softened sheet 25 through an upper compressed air box and then the sheet 25 is formed with a compressed air into a shape of the paper tray container 22. In this case, the pressing member 29 is arranged, so that no compressed air is applied to the sheet 25 at the upper surface of each of the flange plates and so the sheet 25 does not enter into a clearance between the abutting lines of the ends of each of the flange plates, no grooves are formed and a flat shape is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetically sealed composite tray container capable of being completely sealed when sealed with a lid material, and more particularly to a paper tray having a flange formed by cutting a die-cut paperboard. Placing the tray container in a mold and forming a plastic sheet (including film) by sheet molding
The present invention relates to a composite tray container obtained by laminating and adhering to the inner surface of a paper tray container and the upper surface of a flange portion, which can be completely sealed when sealed with a lid material. In the present invention, the sheet molding means a molding method in which air is applied to a heated and softened sheet, and the shape is fixed by cooling after deformation, and vacuum forming, pressure forming, and vacuum forming and pressure forming. Combinations and the like are typical.

[0002]

2. Description of the Related Art Conventionally, there has been known a composite tray container in which a plastic sheet is adhered and laminated on the inner surface of a paper tray container. Although this composite tray container is generally used as a food packaging container in combination with a lid material, it is superior in water resistance and oil resistance as compared with a paper container,
It is suitable for microwave ovens because it can pack foods containing water and oil and has excellent heat resistance. In addition, the composite tray container can display contents and the like on the surface of the container body and the lid material, and does not require an exterior such as an outer box. Can also contribute.

[0003] However, this composite tray container has a problem that it is extremely difficult to completely seal it with a lid material, and in many cases, it is used for limited types of food packaging such as frozen foods that can be stored frozen. Used in Therefore, in order to develop applications in many types of food packaging fields, it is indispensable to give the composite tray container complete sealing with a lid material and improve the storage stability of the food.

[0004] The reason why the composite tray container is inferior in the complete sealing property by the lid material mainly lies in its structure and molding method. In order to manufacture this composite tray container, as shown in FIG. 2, a die-cut paperboard 21 is made into a box to create a paper tray container 22 made of only paperboard. The paper tray container 22 has a flange formed over the entire periphery of the opening. The prepared paper tray container 22 is placed in the molding die 23 of the molding die 24, and then sent to a sheet forming step. In the sheet forming step, after the plastic sheet 25 is heated and softened from both sides by the heater 26, the upper mold 27 is heated.
Transfer to the bottom of The softened sheet is fixed with a clamp, and the mold 24 and the upper mold 27 are brought into close contact with the sheet. The upper mold 27 is a pressurized air box, and presses compressed air from a blowing port (not shown) to laminate and bond the softened sheet to the inner surface of the paper tray container 22 and the upper surface of the flange. A ventilation hole (not shown) is provided in the molding die 23, and a ventilation tube (not shown) is provided in the lower part of the molding die 24. It is designed to be exhausted. The air may be exhausted by reducing the pressure. That is, vacuum forming and pressure forming can be combined.

[0005] Usually, an adhesive such as a hot melt type or an emulsion type is previously applied to one side of the paperboard on the inner side of the paper tray container 22, and in the sheet forming step, thermoforming and thermal bonding are performed. Done at the same time. When the plastic sheet has a heat-sealable resin layer, it is not always necessary to apply the adhesive to the paperboard. After the sheet forming step, the laminate is sent to a press forming step, where unnecessary portions around the flange are trimmed to obtain a composite tray container 28 having a structure in which a paperboard and a plastic sheet are laminated and bonded.

As shown in FIG. 1, for example, the paper tray container 22 constituting the composite tray container 28 is assembled by being connected to the rectangular bottom plate 1 and the bottom plate. A pair of side wall plates 2, 2 and a pair of side wall plates 3, 3 standing up at an angle with respect to each other, and upper ends of the side wall plates 2, 2, and the side wall plates 3, 3 horizontally extend outward. Flange plates 4 and 5 are provided, and each flange plate 4 and 5 has a structure in which the ends thereof abut each other. Although the end portions of the flange plates 4 and 5 are die-cut from the paperboard so as to be as close as possible, the butted portions (joints) 6 have a very small size as shown in FIG. A simple gap 7 is formed. At the time of sheet forming, as shown in FIG. 5 (b), the softened sheet 25 comes into close contact with the flange plates 4 and 5, and is then pushed by compressed air to form the flange plate 4 as shown in FIG. 5 (c). And 5
Small gap 7 at seam 6 where the ends of
Then, the softened sheet enters and forms fine grooves 31.

[0007] The composite tray container is sealed with a lid after filling the inside with food, and this sealing is performed by bonding the lid and the sheet portion on the upper surface of the flange plate. However, at the time of sheet molding, FIG.
If a minute groove 31 as shown in (c) is formed in the sheet portion on the upper surface of the flange plate, even if it is sealed with a lid material,
This groove serves as a ventilation hole, so that the inside of the composite tray container cannot be completely sealed. Therefore, such a composite tray container has insufficient gas barrier properties and is difficult to gas-displace packaging. Also, when packaging a food containing a liquid, the liquid may leak out of the groove.

Hitherto, for the purpose of increasing the connection strength between the flange plates of the composite tray container, it has been proposed to adopt a structure in which the flange plates are overlapped with each other (Japanese Patent Application Laid-Open No. 10-101555, JP-A-10-1010
No. 56). However, when the flange plates overlap each other, a gap is formed at one end of the overlap portion between the flange plates due to the thickness of the paperboard used, and the flatness of the flange itself is impaired by the overlap portion. More specifically, as shown in FIG.
When the end portions of the sheets 5 and 5 are overlapped, a step is formed in the overlap portion 61, and when the sheet 25 is laminated and adhered thereon, the flatness is impaired. If the sheet is sealed from above with a lid material, a gap is formed in the step 62 and the sheet becomes a ventilation hole, and the sealing property is impaired. Also, if the flatness of the flange part is impaired, when sealing with a lid material,
Poor sealing may occur. Therefore, in the method of overlapping the flange plates,
It is difficult to obtain a composite tray container having excellent sealing properties.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a composite tray container in which a plastic sheet is laminated and adhered to the inner surface of a paper tray container and the upper surface of a flange plate.
To provide a hermetically sealed composite tray container in which a plastic sheet laminated and adhered to the upper surface of each flange plate is flat, and a groove of the plastic sheet is not formed at a joint where the ends of each flange plate abut each other. It is in.
More specifically, an object of the present invention is to dispose a paper tray container having a flange portion formed of a box made of a die-cut paperboard in a mold, and form a plastic sheet by sheet molding on the inner surface of the paper tray container and An object of the present invention is to provide a hermetically sealed composite tray container, which is a composite tray container laminated and adhered to an upper surface of a flange portion and can be completely sealed when sealed with a lid material.

The inventors of the present invention have conducted intensive studies to overcome the problems of the prior art. As a result, when a plastic sheet is laminated and adhered to the inner surface of a paper tray container and the upper surface of a flange plate by sheet molding, each flange is formed. Placing the holding member on the plastic sheet superimposed on the upper surface of the plate, forming the sheet while preventing the plastic sheet from entering the joint where the ends of each flange plate abut each other and forming a groove By doing so, the plastic tray laminated and adhered to the upper surface of each flange plate is flat, and the plastic sheet groove in which the groove of the plastic sheet is not formed at the joint where the ends of each flange plate are butted together. I found what I could get. The composite tray container of the present invention, including the flange portion, has good adhesion to the softened plastic sheet as well as the conventional product, and because the plastic sheet of the flange portion is not formed with fine grooves, There is no problem of poor sealing due to the lid material, and the sealing property is extremely excellent. The present invention has been completed based on these findings.

[0011]

According to the present invention, there is provided a polygonal bottom plate, and a plurality of side wall plates which are connected to the bottom plate and assembled and stand at an angle with respect to the bottom plate. The upper end of each side wall plate is provided with a flange plate extending outward, and a plastic sheet is provided on the inner surface of the paper tray container and the upper surface of the flange plate having a structure in which the ends of each flange plate are butted against each other. A composite tray container that is laminated and bonded, wherein the plastic sheet laminated and bonded to the upper surface of each flange plate is flat,
A hermetically sealed composite tray container is provided, wherein a groove of a plastic sheet is not formed at a joint where the ends of the flange plates abut each other.

The paper tray container used in the present invention is typically assembled with a rectangular bottom plate 1 connected to the bottom plate, and stands up at an angle to the bottom plate. A pair of side walls 2,2 and a pair of side walls 3,3, and flange plates 4,5 having upper ends of the side walls 2,2 and the side walls 3,3 horizontally extended outward. This is a paper tray container having a structure in which the ends of the flange plates 4 and 5 are butted against each other. In this case, in the composite tray container of the present invention, a plastic sheet is laminated and adhered on the inner surface of the paper tray container and the upper surface of the flange plate, and the plastic sheet laminated and adhered on the upper surface of each of the flange plates 4 and 5 is formed. This is a hermetically sealed composite tray container that is flat and has no plastic sheet groove formed at the joint 6 where the ends of the flange plates 4 and 5 abut each other.

According to the present invention, a plastic sheet is laminated and adhered to the inner surface of the paper tray container and the upper surface of the flange plate by sheet molding. There is provided a hermetically sealed composite tray container formed by arranging a pressing member and forming a sheet while preventing a plastic sheet from entering and forming a groove at a joint where ends of respective flange plates abut each other.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A paper tray container serving as a base of a composite tray container of the present invention has, for example, a structure as shown in FIG. A paper tray container shown in FIG. 1 has a rectangular bottom plate 1 and a pair of side wall plates 2 and 2 and a pair of side wall plates 2 connected to the bottom plate and assembled and standing up at an angle with respect to the bottom plate. Side wall plates 3, 3;
The upper end of each of the side wall plates 2 and 2 and the side wall plates 3 and 3 is provided with flange plates 4 and 5 extending horizontally outward, and a structure in which the ends of the flange plates 4 and 5 are butted against each other. Have.

In the paper tray container shown in FIG. 1, each of the flange plates 4 and 5 has a rectangular shape, and the joint 6 of the butting portion of the ends thereof is aligned with one side of the rectangular bottom plate 1. However, the container of the present invention is not limited to such a structure. For example, the end of each of the flange plates 4 and 5 is cut obliquely, and the joint of the abutting portion between the ends is a rectangular bottom plate 1.
May be oblique and not parallel to one of the sides. Further, a corner portion formed by a corner plate may be formed integrally with a corner portion sandwiched between the side wall plates 3 and 4. What is important in the present invention is that the flange plates have a structure in which their ends abut each other without overlapping. The details of the shape of the paper tray container can be varied as desired, including the formation of additional portions. It is preferable that the gap between the joints where the ends of the flange plates abut each other is as small as possible. The angle of the side wall plate to the bottom plate is usually an obtuse angle.

As another example of the paper container, there is a container assembled by using a die-cut paperboard as shown in FIG. The paper container in FIG. 7 includes a bottom plate 71, side wall plates 73 and 74, flange plates 74 and 75, and an overlapping piece 76. The overlapping piece 76 is folded inward and overlaps the side wall plate. As shown in FIG. 8, the paper container may be a polygon other than a quadrangle such as an octagon. As shown in FIG. 9, the bottom plate is rectangular, but the opening may be octagonal.

In order to prepare such a paper tray container, a paperboard that has been previously cut into a predetermined shape is used so that it can be assembled into a tray-shaped container having a desired shape. The basis weight of the paperboard is usually 150 g / m ² or more, preferably 190~500g / m ^2, more preferably 250 to
400 g / m ² . The thickness of the paperboard is usually 0.1 mm
The above is preferably 0.1 to 1.2 mm, more preferably 0.15 to 1.0 mm. However, depending on the use, even if the basis weight and the thickness are out of the above-mentioned ranges, they can be used. For paperboard, for the purpose of improving water resistance,
One side on the outer surface side of the container may be subjected to a water repellent process, a laminating process, or the like. The outer surface of the paperboard can be printed. One side, which will be the inner surface of the paperboard container, can also be printed as desired.

An adhesive can be applied in advance to one side of the paperboard, which is the inner side of the paper tray container. The adhesive layer allows the paper tray container and the plastic sheet to be heat-sealed during sheet formation. The type of the adhesive is not particularly limited, and an adhesive such as a hot melt type or an emulsion type which has been conventionally used in this field can be suitably used. The coating amount of the hot melt type adhesive is usually 1 when expressed in thickness.
It is 0 to 30 μm, preferably 15 to 25 μm, and typically about 20 μm. For emulsion type adhesives, coating amount is in the range of usually 1-8 g / m ^2, typically from 5 g / m ^2. However, the amount of the adhesive applied can be varied outside the above range depending on the type and use of the adhesive.

It is preferable to select an optimum range for the basis weight of the paperboard, the type of the adhesive, the amount of the adhesive applied, and the like, depending on the type of food to be packaged and the filling conditions of the food. For example,
In the case of a jam container that hot-fills jam at 80 ° C,
It is preferable that the paperboard has a basis weight of 320 g / m ² and a hot-melt type adhesive is applied at an application amount of 20 μm. In the case of a yogurt container filled with yogurt at room temperature,
It is preferable that the paperboard has a basis weight of 260 g / m ² and the emulsion type adhesive is applied at a coating amount of 5 g / m ² .
In addition, as a plastic sheet, a multilayer sheet (including a multilayer film) having a heat sealable resin layer as the innermost layer
In the case where is used, it is not always necessary to apply an adhesive to the paperboard, and the multilayer sheet can be melt-bonded to the inner surface of the paper tray container or the upper surface of the flange plate during sheet formation.

The sheet forming for laminating and bonding the plastic sheet to the paper tray container is performed by the sheet forming step shown in FIG. 2 as described above. In the present invention, when a plastic sheet is laminated and adhered to the inner surface of the paper tray container and the upper surface of the flange plate by sheet forming, a pressing member is arranged on the plastic sheet superimposed on the upper surface of each of the flange plates 4 and 5. And each flange plate 4 and 5
The sheet is formed while preventing the plastic sheet from entering the seam 6 where the ends of the abutment abut against each other to form a groove. As shown in FIG. 2, the die-cut paperboard 21 is made into a box, and the paper tray container 22 made of only the paperboard is formed.
As shown in FIG. 3, the paper tray container 22 has a relatively large flange portion, and is finally trimmed by a cut line 30 in a pressing step.

In the present invention, as shown in FIGS.
At the time of sheet forming, the pressing member 29 is arranged on the plastic sheet superimposed on the upper surface of each of the flange plates 4 and 5, and in this state, the compressed air is placed on the heated and softened sheet via the upper die air box. To form the sheet into a paper tray container. At this time, since the pressing member 29 is disposed, the compressed air is not applied to the sheet on the upper surface of the flange, the sheet enters the gap between the joints between the ends of the flange plates,
There is no formation of the groove 31 as shown in FIG. Since the sheet arranged on the upper surface of the flange portion is heated and softened, the sheet can be adhered to the upper surface of each flange plate by pressing with a pressing member.

As shown in FIG. 3, the shape of the pressing member is usually formed so as to cover the entire circumference of the flange portion. However, if desired, only the joint between the end portions of each flange plate is covered. It may be formed as follows. The pressing member can be attached to the inside of the upper mold via a sprung member or the like, for example. Further, the holding member may be formed in a frame shape, and may be placed on the upper surface of the flange when the sheet is formed. Except for using the pressing member, the plastic sheet laminated and adhered on the upper surface of each of the flange plates 4 and 5 is flat by forming the sheet in the same process as that shown in FIG. And 5 can produce a hermetically sealed composite tray container in which a groove of a plastic sheet is not formed at a seam 6 where the ends thereof abut each other.

As the plastic sheet (including the film), various single-layer or multi-layer sheets having heat sealing properties can be used. By selecting this sheet material, the composite tray container can be provided with barrier properties such as gas barrier properties, water vapor barrier properties, and aroma barrier properties, and can be used as a heat-resistant material that enables high-temperature filling and microwave heating of food. Can be given. Specific examples of the plastic sheet include (1) single-layer sheets such as A-PET (amorphous polyethylene terephthalate film), PP (polypropylene film), HIPS (high impact polystyrene sheet), PC (polycarbonate film), PVC (polyvinyl chloride sheet) and the like. (2) As the multilayer sheet, for example, A-PET / CPP (A-PET)
/ Cast polypropylene film), A-PET / E
VOH (A-PET / ethylene vinyl alcohol copolymer film), K-coated nylon / CPP, HIPS
/ EVOH, PC / EVOH, PVC / EVOH and the like. Between each layer of the multilayer sheet,
If necessary, an adhesive layer may be provided.

In addition to the multilayer sheet, for example,
A multi-layer structure of a surface layer / core layer / seal layer, in which an adhesive layer is disposed between each layer as needed, may be mentioned. In application fields where a high degree of gas barrier property is required, it is preferable to arrange a gas barrier film such as EVOH, PVDC, or MXD-6 nylon as the core layer. As the surface layer, A-PET, PP, HIP
Sheets or films of S, PC, PVC, etc. are preferred. The sealing layer is not particularly limited, but can be appropriately selected depending on the use, such as a heat-resistant sealant or an easy-peeling sealant. Examples of the heat-sealing resin used for the sealing layer include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), and ethylene-acrylic ester-maleic anhydride terpolymer. Examples of the polymer include a carbonyl group-containing ethylene copolymer such as a polymer, a maleic anhydride graft-modified polyolefin, a modified ethylene / acrylic acid copolymer, and an ethylene / methyl methacrylate / acrylic acid terpolymer. Linear low-density polyethylene (LLDP) obtained by copolymerizing ethylene and α-olefin using a single-site catalyst
E), very low density polyethylene (VLDPE), elastomers and the like can also be suitably used. Specific examples of such a multilayer sheet include, for example, PP / EVOH /
EVA, PP / EVOH / VLDPE and the like can be mentioned. By selecting the configuration of the multilayer sheet, for example, easy peeling can be imparted in combination with a lid material. The thickness of each layer of the multilayer sheet can be appropriately selected according to the purpose of use.

The thickness of the plastic sheet is usually 100
It is about μm to 1 mm, preferably about 150 to 500 μm. However, depending on the application, a thinner film or a thicker sheet may be used. The sealable composite tray container of the present invention can exhibit excellent sealability when used in combination with a lid material. That is, the lid material seals with the upper surface of the flange portion of the composite tray container of the present invention, but since the plastic sheet laminated and adhered to the upper surface of the flange portion is flat, there is no occurrence of sealing failure, The inside can be substantially completely sealed.

The lid material is not particularly limited, and those conventionally used in this field, such as paperboard, single-layer film, and multilayer film, can be used. Further, those having barrier properties such as gas barrier properties, water vapor barrier properties, and aroma barrier properties, and those having heat resistance capable of high-temperature filling or microwave heating can be used. Specific examples of the lid material include, for example, paper / sealant, PET / sealant, PP / sealant, PE
Those having a layer constitution such as T / EVOH / sealant and PP / EVOH / sealant can be mentioned. The name of the food to be filled, the cooking method, the name of the manufacturer, and the like can be printed on the outer surface of the lid material.

The composite tray container of the present invention can be formed by selectively combining a plastic sheet and a cover material, for example, gas barrier property, water vapor barrier property, aroma barrier property, etc., easy peel property, high temperature filling property. , Frozen storage / distribution (-30 ° C), microwave oven suitability,
Various functions such as steam cooking ability can be provided. Further, gas replacement packaging using nitrogen gas, carbon dioxide gas, a mixed gas thereof, or the like can be performed.

[0028]

The present invention will be described more specifically below with reference to examples and comparative examples. [Example 1] The basis weight (basis weight) of 320 g / m ² paperboard die-cut to prepare a board 21 which is die-cut shown in Fig. On one side of the paperboard, apply a hot-melt adhesive in advance.
It was applied with a thickness of μm. The paperboard was made into a box to make a paper tray container 22. The paper tray container has a bottom plate with a length of 100 mm x 140 mm and an opening of 120 mm x
The width was 160 mm, the width of the flange plate was 10 mm, and the length of the side wall plate was 40 mm. The angle of the side wall plate to the bottom plate was 105 degrees. The paper tray container 22 was placed in the forming die 23 of the forming die 24, and then sent to a sheet forming step. In the sheet forming process,
Rolled plastic sheet (A-PET /
An EVOH film (thickness: 120/30 μm) 25 was heated from both sides with a heater 26 to soften it, and then transferred to the lower part of an upper mold 27. Fix the softened sheet with a clamp,
The molding die 24 and the upper die 27 were brought into close contact with the sheet. On this occasion,
A pressing member 29 capable of covering the entire flange portion as shown in FIG. 3 is attached to the inside of the upper die 27 via a sprung member, and the entire flange portion is covered by the pressing member, and Pressed from above. Upper mold 27
Is a pressurized air box, and the softened sheet is laminated and adhered to the inner surface of the paper tray container 22 and the upper surface of the flange by applying compressed air from a blowing port. next,
The composite tray container 28 was sent to a press molding process, and unnecessary portions around the flange were trimmed to obtain a composite tray container 28.

The composite tray container thus obtained has a flat sheet laminated and adhered to the upper surface of the flange portion, and a plastic sheet is provided at the seam 6 where the ends of the flange plates 4 and 5 abut against each other. It was confirmed that no groove was formed. After the jam was hot-filled in this composite tray container at 80 ° C., a multilayer film having a layer configuration of PET / EVOH / sealant was used as a lid material, and this lid material was heat-sealed to the flange portion of the composite tray container. . At the time of heat sealing, a mixed gas (nitrogen / carbon dioxide = 90 /
(10% by volume). It was confirmed that the seal portion was completely sealed. The same operation as described above was performed except that water was filled at room temperature instead of hot filling the jam. Even if this water-filled container was shaken by hand, water did not exude from the seal portion.
Also, put the water-filled container in a microwave oven,
For 60 seconds, there was no leakage of water from the seal.

Comparative Example 1 A composite tray container was prepared in the same manner as in Example 1 except that no restraining member was used. It was confirmed that a groove of the plastic sheet was formed at the joint 6 where the ends of the flange plates 4 and 5 were butted against each other. When the composite tray container was filled with water and shaken by hand, it was confirmed that a small amount of water leaked from the seal portion.

[0031]

According to the present invention, there is provided a composite tray container in which a plastic sheet is laminated and adhered to the inner surface of a paper tray container and the upper surface of a flange plate. The present invention provides a hermetically sealed composite tray container in which a flat sheet is formed and a groove of a plastic sheet is not formed at a joint where the ends of the flange plates abut each other. The composite tray container of the present invention has no leakage of the contents from the sealing portion with the lid material, and, by appropriately selecting the material of the plastic sheet and the lid material, barrier properties, easy peelability, high-temperature filling properties, Functions such as cryopreservation / distribution, microwave cooking, and steaming can be imparted. Further, the composite tray container of the present invention is capable of gas replacement packaging. Since the composite tray container of the present invention utilizes the rigidity of paper, the weight can be reduced and the amount of plastic material can be reduced as compared with a container made of only a plastic material. Further, since the composite tray container of the present invention does not require an exterior such as an outer box, the amount of waste after use can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of a paper tray container used in the present invention.

FIG. 2 is an explanatory view showing an example of a method for manufacturing a composite tray container of the present invention.

FIG. 3 is an explanatory view (front view) showing one step of the method for manufacturing a composite tray container of the present invention.

FIG. 4 is an explanatory view (cross-sectional view) showing one step of the method for producing a composite tray container of the present invention.

FIG. 5 is an explanatory view showing that a groove of a plastic sheet is formed at a joint (gap) where ends of flange plates abut each other during sheet molding.

FIG. 6 is an explanatory diagram showing a step generated when ends of the flange plates are overlapped.

FIG. 7 is a cut-out paperboard showing another example of the paper tray container used in the present invention.

FIG. 8 is a view showing another example of a paper tray container used in the present invention.

FIG. 9 is a view showing another example of a paper tray container used in the present invention.

[Explanation of symbols]

 1: Bottom plate 2: Side wall plate 3: Side wall plate 4: Flange plate 5: Flange plate 6: Seam where ends of flange plates are butted together 7: Gap between seams 21: Die-cut paperboard 22: Made Boxed paper tray container 23: Mold 24: Mold 25: Plastic sheet 26: Heater 27: Upper mold 28: Product 29: Holding member 30: Final cut line 31: Sheet groove 61: For each flange plate Overlap portion 62: step 71: bottom plate 72: side wall plate 73: side wall plate 74: flange plate 75: flange plate 75: overlapping piece

Claims (3)

[Claims] 1. A polygonal bottom plate, a plurality of side wall plates which are connected to and assembled with the bottom plate and stand up at an angle with respect to the bottom plate, and an upper end of each side wall plate is provided. A composite tray container comprising a paper tray container having a structure in which end portions of respective flange plates abut against each other and a plastic sheet laminated and adhered to an inner surface and an upper surface of the flange plate. hand,
A plastic composite sheet laminated and bonded to the upper surface of each flange plate is flat, and a groove of the plastic sheet is not formed at the joint where the ends of each flange plate abut against each other; container. 2. A paper tray container comprising: a rectangular bottom plate 1;
A pair of side walls 2, 2 and a pair of side walls 3, 3, which are connected to and assembled with the bottom plate and stand up at an angle with respect to the bottom plate;
A paper tray container having a structure in which the upper ends of the side walls 3 and 3 are provided with flange plates 4 and 5 horizontally extending outward, and the ends of the flanges 4 and 5 are butted against each other. The hermetically sealed composite tray container of claim 1. 3. A plastic sheet is laminated and adhered to the inner surface of the paper tray container and the upper surface of the flange plate by sheet molding. At this time, a pressing member is arranged on the plastic sheet superimposed on the upper surface of each flange plate. 3. The hermetically sealed composite tray container according to claim 1, wherein a sheet is formed while preventing a plastic sheet from entering a joint where the ends of the flange plates abut each other to form a groove.