JPH09255066A - Heat-insulative folding-case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a bottom plate provided with sufficient heat-resistant and oil-resistant properties, by forming the thin bottom plate made of a dense synthetic resin material with a composite layer composed of a synthetic resin base material having a high melting point and excellent heat-resistant and oil-resistant properties and a thin coating layer made of a thermoplastic and low-melting point synthetic resin material. SOLUTION: A bottom plate 2 is dropped in a frame material 1 and the extended parts of the bottom plate 2 are fitted so as to put on the upper end faces of the frame material 1. A hot plate is pressed from the upper side as shown in the arrow and the welded layer formed on the rear face of the extended part of the bottom plate and the upper end face of the frame material 1 are welded together to form connection parts 5. Since the welded faces are formed by conventional low melting point thermoplastic resin, conventional welding conditions can be applied. Since the inside face of the folded case obtained in such a way is formed with a heat-resistant and corrosion-resistant resin material, even if the contents are heated materials, the retaining force of the bottom plate is prevented from decreasing. And further, the inside of container is hermetically sealed perfectly against the outside air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called simple container for foods suitable for storing foods having excellent heat resistance, in which a bottom plate made of a synthetic resin thin plate is welded to a lower end surface of a foam synthetic resin frame material. Regarding folding boxes.

[0002]

2. Description of the Related Art When assembling this folding box, a thin plate made of the same thermoplastic synthetic resin is applied as a bottom plate to the lower end face of a foam frame made of thermoplastic synthetic resin, and the heat is applied from the opposite side of the bottom plate. The bottom plate and the bottom plate of the frame member are partially melted and welded by pressing the plate against each other.

Such a folding box looks and is lighter than various types of paper and integrally molded synthetic resin containers.
Since it is relatively strong and can withstand the storage of heavy molded food such as sushi, it is widely used as a simple container for taking out various foods.

When the foam frame material and the bottom plate are welded, it is not merely the assembling of the container, but the securing of the strength of the container itself and the prevention of the leakage of water from the container surface through the welding surface are required. It is necessary to have a more complete welded state, for which the melting point is 85 ° C to 90 ° C.
Using a synthetic resin such as polystyrene, which has a low degree of excellent thermoplasticity, or forms a concavo-convex pattern on the surface of the hot plate that is pressed to improve the joining state, A perfect bond is achieved by the biting of the mutually welded surfaces.

[0005] In recent years, in addition to the requirement for complete joining, there is an increasing demand for foods contained in containers that contain a large amount of juice or highly processed foods. In order to meet this requirement, As a material for forming a container, in place of conventional polystyrene, it has been attempted to use a synthetic resin having excellent heat resistance and oil resistance, such as polypropylene or a filler containing polypropylene.

[0006]

However, the synthetic resin excellent in heat resistance and oil resistance is inferior in foaming property and rigidity, and cannot be used as a foam frame material, and is only used as a dense material. In this case, the advantages of the lightweight and cheap simple container using the foamed resin frame material are lost. Therefore, as a simple container using a synthetic resin material with excellent heat resistance and oil resistance, as a practical matter, a conventional low melting point foam synthetic resin material with excellent thermoplasticity is used as the frame material, and only the bottom plate is heat resistant. There is only a combination of using a high melting point synthetic resin material with excellent oil resistance.

However, it is not possible to use 2
When fusing different types of synthetic resin materials, it is difficult to heat fuse them due to their different characteristics.In addition, considering the melting point of the high melting point synthetic resin material, the temperature of the hot plate is set to a high temperature. On the other hand, on the other hand, in fusion bonding under such a high temperature, the low melting point foamed synthetic resin material used as the frame material will melt down and the joint part will be deformed, and its commercial value will be increased. There is a problem of losing.

Therefore, it is conceivable to use an adhesive instead of the heat fusion, but this is not desirable in terms of hygiene.

As described above, the frame material made of the foamed synthetic resin material having a low melting point is not melted down, and the high melting point synthetic resin material used as the bottom plate is adequately partially melted for welding. Control over temperature is extremely difficult.

The problem to be solved in the present invention is to assemble a simple container for food by welding a bottom plate made of such a synthetic resin having a poor heat-welding property to a frame material made of a low-melting foam synthetic resin material, The purpose of the present invention is to solve a problem due to an incompletely joined state due to a difference in melting point of each other, to obtain a folded box having an excellent joined state and having a bottom plate having sufficient heat resistance and oil resistance.

[0011]

SUMMARY OF THE INVENTION The present invention provides a folding box having a structure in which a frame material made of thermoplastic foam synthetic resin and a bottom plate made of a dense synthetic resin thin plate are heat-sealed to each other. A thin base plate made of resin is composed of a base material of high melting point synthetic resin having excellent heat resistance and oil resistance, and a composite layer in which a thin coating layer of thermoplastic low melting point synthetic resin material is formed on the base material. Is characterized by.

As the frame material, a thermoplastic synthetic resin having a melting point of 80 ° C. to 90 ° C. such as polystyrene which has been conventionally used can be used.

As a synthetic resin thin plate, a polypropylene (pp) having a thickness of 200 to 600 μm and a melting point of about 110 ° C. is used as a base material of a high melting point synthetic resin having excellent heat resistance and oil resistance. On top of which a thermoplastic low melting point synthetic resin film such as polystyrene (p
p. A ps polymer alloy layer) is used.

As the coating material, when the same material as the synthetic resin forming the frame material is fused, the respective melt layers are easily mixed, and a high-strength joint portion in which the materials are melted can be formed. convenient. A thickness of 100 μm is sufficient for the thickness of the low melting point synthetic resin film.
The total thickness of the bottom plate is usually 20 depending on the food stored.
It may be about 0 to 600 μm.

As the bottom plate of the present invention, a thermoplastic low melting point synthetic resin film formed on a high melting point synthetic resin substrate having excellent heat resistance and oil resistance is formed on the entire surface of the bottom plate. Alternatively, it may be provided only on the portion corresponding to the lower end surface of the frame material of the welding partner.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The simple container for food according to the present invention is made of the same low melting point synthetic resin in which the frame material and the coating layer of the bottom plate are melted and fused to each other. By lightly pressing a hot plate heated to a temperature slightly higher than the melting point of, the frame material and the coating layer on the surface of the bottom plate are melted and joined.

[0017]

【Example】

Example 1 This example is an example in which a heat-sealed portion is formed on the lower end surface of the frame member and the upper edge of the bottom plate.

FIG. 1 shows the constituent members of a folding box. Reference numeral 1 is a frame material, and a band-like material having a thickness of 3 mm to 7 mm and made of expanded polystyrene material having a melting point of 85 ° C.
1 is inserted and bent, and both ends 12 are heat-welded to form a rectangular frame. Reference numeral 2 denotes a bottom plate made of a composite material of a heat resistant base material and an adhesive layer formed by extrusion molding.

FIG. 2 shows a sectional shape of the bottom plate 2 shown in FIG. 1 taken along the line AA. As shown in the figure, a rise 21 is formed on the outer edge of the bottom plate 2, and a welding surface 22 is formed on the outer side thereof. The bottom plate 2 has a heat resistance of 100 μm to 40 μm.
An adhesive layer of styrene-polyethylene-polymer-alloy (pp.ps) having a thickness of 50 μm to 150 μm is formed on the entire surface of one side of the base material 3 made of polypropylene (pp) having a thickness of 0 μm.
The film 4 is formed. The adhesive layer film 4 is
The base material 3 may be applied on both sides regardless of one side. In short, it is sufficient that the film 4 as the adhesive layer is formed at least only on the portion of the welding surface 22 at the peripheral edge of the bottom plate 2 that is welded to the lower end surface of the frame material 1.

FIG. 3 shows a joined state of the frame member 1 and the bottom plate 2. As in the conventional case, the welding surface 22 of the peripheral edge of the bottom plate 2 is applied to the lower end face of the frame member 1 shown in FIG. A hot plate (not shown) is pressed from the outside as shown by an arrow to form a joint part 5 in which the parts are partially melted to manufacture a folding box. The joint portion 5 between the frame material 1 and the bottom plate 2 obtained in this way is
The lower end surface of the base plate and the coating of the bottom plate 2 are in a melted and integrated state, and the inside of the container is completely joined to the outside air to form a joined state, and moreover, it has excellent heat resistance and oil resistance. The function of the base material 3 of the bottom plate 2 can be sufficiently fulfilled.

Example 2 This example is an example in which a heat-sealing portion is formed on the lower end surface of the frame member and the upper surface of the edge of the bottom plate.

FIG. 4 shows constituent members of the folding box according to this embodiment, and 1 is a frame member similar to that of the first embodiment. Unlike the case of the first embodiment, the second bottom plate is formed in a relatively deep middle plate type, and an outward projecting portion 23 is formed at the upper edge. Then, at the time of assembly and molding, the container-shaped bottom plate 2 is dropped into the frame material 1, the overhang 23 of the bottom plate 2 is placed on the upper end surface 13 of the frame material 1, and the frame material 1 is placed on the back surface thereof.
It is designed to form a welded surface with.

FIG. 5 shows a sectional shape of the bottom plate 2 shown in FIG. As shown in the figure, the entire bottom plate 2 is formed of a heat-resistant base material 3, and a coating 4 serving as an adhesive layer is formed on the entire lower surface of the overhang 23 of the bottom plate 2.

FIG. 6 shows a joined state of the frame member 1 and the bottom plate 2. The bottom plate 2 is dropped into the frame member 1 and the overhang 23 of the bottom plate 2 is placed on the upper end surface 13 of the frame member 1. Apply in the state. As shown by an arrow, a hot plate (not shown) is pressed from above to melt the welding layer formed on the back surface of the overhang 23 of the bottom plate 2 and the upper end surface of the frame member 1 to form the joint 5. . Since the welding surfaces at this time are each formed of a conventional low melting point thermoplastic resin, the conventional welding conditions can be applied. The inner surface of the folding box thus obtained is formed of a heat-resistant and corrosion-resistant resin, and the holding force of the bottom plate does not decrease even if the stored contents are heated. The joint portion 5 of the frame member 1 and the bottom plate 2 is in a state where the lower end surface of the frame member 1 and the coating of the bottom plate 2 are melted and integrated, and the joint state in which the inside of the container is completely sealed with the outside air is provided. The base material 3 of the bottom plate 2 which is formed and has excellent heat resistance and oil resistance can sufficiently fulfill its function.

[0025]

According to the present invention, the following effects can be obtained.

(1) It is possible to obtain a simple food container having excellent heat resistance and oil resistance, without changing the conventional assembly process.

(2) The welded portion between the frame member and the bottom plate has excellent joint strength and sealing properties.

(3) Since the frame material and the inner plate are basically different in material, the welding temperature can be set relatively easily, so the process is simple.

(4) By forming the bottom plate in the form of a medium plate, it is possible to reliably prevent leakage of juice such as bento.

(5) A heat-resistant type folding box container having a high quality can be supplied at a very low cost.

(6) It does not melt even when heated in a microwave oven.

[Brief description of drawings]

FIG. 1 shows components of a first embodiment of the present invention.

FIG. 2 shows a cross section of the bottom plate shown in FIG.

FIG. 3 shows a cross section of the folded box after assembly.

FIG. 4 shows components of another embodiment of the present invention.

5 shows a cross section of the bottom plate shown in FIG.

FIG. 6 shows a cross section of the folded box after assembly.

[Explanation of reference numerals] 1 frame material 11 cuts 12 both ends of the strip material 13 upper end surface of the frame material 2 bottom plate 21 outer edge rising of the bottom plate 22
Welding surface 23 Overhang of bottom plate 3 Base material of bottom plate 4 Adhesive layer film 5 Joint part

Claims (1)

[Claims] 1. A heat-resistant folding box in which a frame material made of a thermoplastic foam synthetic resin and a thin bottom plate made of a dense synthetic resin are heat-sealed to each other, wherein the thin bottom plate made of the dense synthetic resin is heat-resistant and oil-resistant. It is characterized by comprising a base material made of a synthetic resin having a high melting point having excellent properties and a composite layer having a thin coating layer of a thermoplastic material having a low melting point formed on the base material.