JP6488560B2 - Microwave-compatible paper molding container - Google Patents

Description

  The present invention relates to a microwave-compatible paper molding container mainly made of paper.

  In recent years, from the viewpoint of environmental impact, paper-molded containers mainly made of paper as a recycling resource have attracted attention. Microwave ovens that can improve the sealing performance and store contents such as soups, beverages or solids and can be heated in a microwave oven Corresponding paper forming containers are required. Conventionally, as a paper-molded container, a part-drawn container has also been put into practical use, but in many cases, a container is molded by bonding a blank. When a paper molding container having a blank bonding portion is heated by a microwave oven, a phenomenon in which scorching is likely to occur occurs in a portion where microwaves tend to concentrate, such as a bonding portion. In particular, in the case of a cup-shaped paper molding container having a yarn bottom portion (leg portion), there is a problem that the inner surface of the yarn bottom portion is likely to be burned during microwave heating.

  For this reason, paper containers that have been devised so as to prevent the occurrence of scorching during the microwave heating of such paper molded containers have been proposed. For example, in a cup type paper container, a body part and a bottom part are integrated to form a leg part, and a hollow part protruding downward is formed at the bottom part via an annular flat plate part inside the leg part. (See Patent Document 1). Further, as another means, an annular inclined wall is formed by bending inward at an inclination angle that leaves a gap between the inner side of the trunk portion and the inner side of the lower portion, and a bottom member is disposed on the annular inclined wall, and the bottom portion A material in which the periphery of a material is thermally bonded to an annular inclined wall has been proposed (see Patent Document 2).

JP 2003-95352 A JP 2005-88955 A

The above-mentioned proposed prevention of scoring in conventional cup-type paper containers is to change the bottom structure of the conventional cup-type paper containers, and the structure is complicated, requiring new manufacturing equipment to replace the conventional manufacturing line. There was a problem that the cost was high.
Accordingly, the present invention provides a paper-molded container for microwave ovens that can easily prevent the occurrence of scorching during microwave heating by a simple means without changing the basic structure of a conventional paper-molded container. It is intended.

Molded paper vessel of the present invention to solve the above problems, a molded paper vessel microwave heating corresponding, Ri Na to form a resin coating layer containing the inhibiting substance burnt to a localized area of the paper forming the container, The resin coating layer is formed by spraying a powder obtained by mixing a non-burning substance powder with a resin powder .
In the case of a cup-shaped paper molding container, the local region is desirably the inner peripheral surface of the yarn bottom portion that is likely to be burned when heated in a microwave oven.
2. The paper-molding container for microwave heating according to claim 1, wherein the local region is an inner peripheral surface of a thread bottom portion of a cup-shaped paper-molding container, wherein the local region of the paper container contains a non-burning substance. A coating layer is formed.
The resin coating layer can be effectively formed with a small amount of coating material at a predetermined position by thermal spraying a powder obtained by mixing a non-burning substance powder with a resin powder.
The type of the resin powder is not particularly limited, but a polyolefin resin powder such as polyethylene or polypropylene having a particle diameter of 100 to 300 μm or a polyester resin powder such as PET, PEN, PLA, or PBT can be effectively employed.
On the other hand, as the non-burning substance powder, calcium carbonate and talc, which are inexpensive low dielectric constant substances, can be used.

According to the paper-molding container compatible with the microwave oven of the present invention, it is possible to easily prevent the occurrence of scorching during microwave heating by simple means without changing the basic structure of the conventional paper-molding container.
And in the case of a cup-shaped paper-molded container, it is easy to burn without changing the bottom shape of the conventional cup-shaped molded container, only by forming a resin coating layer containing a charring prevention substance on the inner peripheral surface of the yarn bottom part. Occurrence can be prevented.
Furthermore, the resin coating layer is formed by spraying a powder obtained by mixing an inorganic powder with a plastic powder, whereby a burn prevention layer can be reliably and inexpensively formed on the inner peripheral surface of the yarn bottom.
Effective by adopting polyolefin resin such as polyethylene and polypropylene as the powder resin, polyester resin such as PET, PEN, PLA, PBT, and calcium carbonate and talc which are inexpensive low dielectric constant materials as the anti-burning substance powder An anti-burning layer can be formed.
And a coating layer can form an anti-burning layer cheaply and reliably by making an average film thickness into 1 mm or less.

(A) is a perspective view of the paper molding container which concerns on embodiment of this invention, (b) is AA sectional drawing in (a).

Hereinafter, embodiments of a paper molding container according to the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a cup-shaped paper forming container (hereinafter simply referred to as a cup-shaped container) mainly composed of paper as a paper forming container according to an embodiment of the present invention. The cup-shaped container 1 is formed by attaching and bonding both end edges of a fan-shaped blank serving as the body portion 2 to form a truncated cone shape or a cylindrical shape, and curling the upper end portion to form an open curled portion 3. A lower end portion is folded inward to form a folded piece 6, and an annular bent portion 9 of a bottom plate 8 drawn into a U-shaped cross section is crimped between them to form a yarn bottom portion 10. A step 4 is formed by pasting both edges of the blank. Further, a bonding portion 5 is formed on the body portion, and paper edges are exposed at both ends of the bonding portion on the inner side and the outer side of the cup. The above structure is the same as that of a conventionally known cup-shaped container.

  Such a paper molding container is a microwave heating container, and the body blank and the bottom member are mainly made of paper, but a polyolefin resin or a polyester resin is laminated to protect the inner and outer surfaces from liquid contents. Alternatively, a composite paper material coated or impregnated, or a material composed of a composite layer having a gas barrier layer as an inner layer as required can be employed, and the material is not particularly limited as long as it can be heated in a microwave oven.

In the cup-shaped container as described above, in the present embodiment, a resin coating containing an anti-burning substance as shown in FIG. Layer 11 was formed to prevent the occurrence of scorching during microwave heating. In this embodiment, the resin coating layer is formed by spraying a powder obtained by mixing a synthetic resin powder having a particle size of 100 to 300 μm and a non-burning substance powder to form the resin coating layer 11 on the inner peripheral surface 7 of the yarn bottom portion.
Although not limited to the following as a powder used for this invention, the material which has easy-adhesion with respect to the paper molding container which has paper as a main component is used. In general paper-molded containers, the base paper substrate is coated with a resin, and it is easy to use a resin of the same type as the surface resin layer or a resin having a lower melting point than the surface resin layer. Is preferable.
Here, the synthetic resin is not particularly limited as long as it is a thermoplastic resin, but it is a high-medium-low density polyethylene, a polyolefin such as polypropylene, a polyester resin such as PET, PEN, PLA, PBT, or a plurality of types of resins. Powder can be used. In addition, as the non-burning powder material, for example, calcium carbonate, talc or the like can be adopted as a material having a low relative dielectric constant. As a result, heat generation due to absorption of microwaves at the yarn bottom portion is reduced, and the occurrence of scorching can be prevented.

The formation of the resin coating layer containing the non-burning substance in the local region of the paper-molded container may be a method using hot melt, hot runner, flame spraying, or the like. However, as in this embodiment, in order to form a container with a very small coating area and a high-speed production line of a container with a small amount of resin, the stringing phenomenon of the coating resin occurs in any of the above methods, and thus the cycle up is limited. It is difficult to apply accurately. In order to overcome this, in the present embodiment, a pre-heating step and a resin spraying step are provided as post-processing steps on the cup-shaped container that is molded and transported in the production line, and hot air is applied to the resin application region in the pre-heating step. Was sprayed to preheat the inner peripheral surface of the yarn bottom part to near the melting point of the coating resin, and then the resin powder was sprayed onto the part in a resin spraying step. As described above, the thermal spraying of the resin powder uses a powder resin powder obtained by mixing a synthetic resin powder having a particle size of 100 to 300 μm and a non-burning substance powder as a raw material, and pressurizing the raw material at a temperature lower than the melting temperature of the resin. It can be formed by thermally spraying a resin gas intermittently or continuously on the inner peripheral surface of the yarn bottom with a spray nozzle (hot air in this embodiment).
By applying the resin coating to the inner peripheral surface of the yarn bottom portion by the method as described above, the resin coating can be accurately performed in a predetermined small area without causing the yarn drawing phenomenon, and the material used can be minimized. it can.

Resin coating was performed on the inner peripheral surface of the thread bottom portion of the cup-shaped container over the entire circumference under the following conditions.
Test container: cup-shaped container (material: same for trunk and bottom)
Material layer structure:
Body: (Inner) Polyethylene (20μm) // Slash slash paper (250g / m ² )
Bottom: (inside) polyethylene (40 μm) // paper 250 g / m ² // polyethylene (15 μm)
Full capacity: 565ml, thread bottom height: 10mm
Thermal spraying conditions:
Powder resin: Powdered polyethylene with an average particle size of 120 μm Anti-burning substance: Calcium carbonate Resin coating film: Width of about 10 mm along the entire inner circumference of the yarn bottom and a film thickness of 1 mm or less. A resin coating layer containing an anti-burning substance was formed. In order to confirm the occurrence of scorching of the cup-shaped container, the following test was conducted.
Container filling contents: 330 ml of water
Microwave oven output: 500W
Heating time: 6 min
The said heating conditions are the normal heating temperature optimal for eating the contents (Udon food).
Situation of scoring: The container of the present example in which the coating layer was formed was thinner in the color of the scoring color generated at the bottom of the yarn than the container without the coating layer as a comparative example.

  As mentioned above, although the embodiment and the Example of the paper-molding container corresponding to a microwave oven of the present invention were explained, the present invention is not limited to these, and a cup-shaped container having a yarn end portion is not necessarily used as a paper-molding container. The present invention is not limited to this, and the present invention can be applied to a variety of structures having a portion that is likely to cause scoring of a microwave-compatible paper-molded container.

  The present invention can suppress the occurrence of scorching in a microwave-compatible paper-molded container with a simple configuration by placing a resin containing a scorch-generating suppression substance at the scorching occurrence site at the time of microwave oven heating in a paper-molded container, A paper-molded container compatible with a microwave oven can be obtained with an inexpensive configuration, and the industrial applicability is high.

DESCRIPTION OF SYMBOLS 1 Cup-shaped container 2 trunk | drum 3 opening curl part 4 level | step difference part 5 trunk | drum bonding part 6 folding | turning piece 7 thread | yarn bottom part inner peripheral surface 8 bottom part 9 cyclic | annular bending part 10 thread | yarn bottom part 11 resin coating layer

Claims (5)

A molded paper vessel microwave heating corresponding, Ri Na to form a resin coating layer containing the inhibiting substance burnt to a localized area of the paper forming the container, the resin coating layer, an anti-material powder burnt resin powder A paper-molded container formed by spraying mixed powder .   The paper forming container according to claim 1, wherein the local region is an inner peripheral surface of a thread bottom portion of the cup-shaped paper forming container. The paper molded container according to claim 1 or 2 , wherein the resin powder is a polyolefin or a polyester resin.   The paper-molding container according to any one of claims 1 to 3, wherein the non-burning substance powder is an inorganic substance having a relative dielectric constant of 2 or less. The paper-molding container according to any one of claims 1 to 4 , wherein the resin coating layer has an average film thickness of 1 mm or less.

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