WO1997007966A1

WO1997007966A1 - Method of molding hot plate of food container lid

Info

Publication number: WO1997007966A1
Application number: PCT/JP1996/000210
Authority: WO
Inventors: Toshiaki Shimono
Original assignee: Athena Kogyo Co., Ltd.
Priority date: 1995-08-25
Filing date: 1996-02-02
Publication date: 1997-03-06
Also published as: JP2935066B2

Abstract

The invention has its object to provide hot insulation during cooking with a poured hot water and eliminate danger of a burn during discharge of hot water by forming a lid (20) of a container, for an instant food, of a foam resin, prevent a print indication on a synthetic resin film (41) integrally laminated to a foam resin sheet (3) from being displaced from a normal position at the time of molding of the lid (20), and enable fine and sharp molding of details of the lid (20). To attain this object, a laminate sheet (30) is hot-plate-molded which comprises the synthetic resin film (41), having a thickness (T2) of 15 to 80 νm, integrally laminated to the foam resin sheet (3) having a thickness (T1) of 0.3 to 0.95 mm. Hot-plate-molding is performed such that a laminate sheet is interposed between a hot plate and a molding die to be softened and closely bonded to the molding die for forming the lid.

Description

Description Hot plate forming method for food container lid

TECHNICAL FIELD The present invention relates to a hot plate forming method for a food container lid, and more particularly to a method for hot forming a laminated sheet obtained by laminating a foamed resin sheet and a synthetic resin film into a lid. Background art

An instant food container such as instant food that is cooked by pouring is composed of a container body for storing the food and a lid for closing the opening of the container body. When foamed resin is used for such instant food containers, the proper insulation temperature can be maintained because of the heat insulation characteristic of the foamed resin, which ensures good heat retention from pouring to draining. There is an advantage that when the hot water is drained by grasping the lid and the container body by hand, the hand does not become so hot that there is no risk of burns. For this reason, attempts have been made to make not only the container body for the ready-to-eat food but also the lid body with foamed resin (Japanese Utility Model Application Laid-Open No. 63-182210).

As a general molding method for molding a laminated sheet in which a synthetic resin film is laminated and integrated on a foamed resin sheet into a molded product with irregularities such as the above-mentioned lid, vacuum pressure molding method There is. However, in the vacuum pressure forming method, there is a softening zone for heating the laminate sheet to a temperature at which molding can be performed before entering the molding zone to soften the laminate sheet, and the laminated sheet softened by the softening zone is used. May drop or bend under its own weight. Then, the laminated sheet thus softened is fed into the forming zone at a constant feed rate. For this reason, the laminated sheet may be bent before entering the molding zone, and the laminated sheet may not be sent to a predetermined position of the molding zone. In other words, when the synthetic resin film of the laminated sheet is printed, the center of the printed display may not be sent to the center of the mold in the molding zone. When the laminated sheet is molded into the lid of a food container in a situation like this, the printed part of the final molded product, such as its contents and cooking method, is not in the correct position. It was found that this was the case.

Under such circumstances, the inventors of the present invention have conducted various studies, and as a result, if a laminated sheet made of a foamed resin sheet and a synthetic resin film is molded by using a hot plate molding method, foods can be obtained. Ascertain the fact that even if a molded article with irregularities such as a container lid is molded, the printed markings on the synthetic resin film are exactly aligned with the correct position of the final molded lid. Was. In addition, the final molding of the food container lid, which is the final molded product from the above-mentioned laminated sheet, can be formed into a hot plate with high precision and sharpness as finely as required. Conditions for mass production As a result of our research, we have completed the present invention.

That is, the present invention is based on the fact that the lid of a food container is made of foamed resin so as to be excellent in heat retention during pouring cooking and not to be burned at the time of hot water discharge. The printed label on the synthetic resin film, which is laminated and integrated with the resin, does not deviate from the proper position, and details that can sufficiently satisfy the fitting property of the lid to the container body etc. It is an object of the present invention to provide a hot plate forming method for a food container lid, which enables fine, sharp, and high-precision molding of the food container lid and can be mass-produced. Disclosure of the invention

The hot plate molding method for a food container lid according to the present invention is characterized in that the lid is a final molded product by hot plate molding a laminated sheet obtained by laminating and integrating a synthetic resin film on a foamed resin sheet. Therefore, the printed display on the synthetic resin film is arranged at a regular position without displacement. The thickness of the foamed resin sheet used in the hot plate molding must be 0.3 to 0.95 mm. The preferred thickness of the foamed resin sheet is from 0.3 to 0.9 mm, the more preferred thickness is from 0.5 to 0.9 mm, and the most preferred thickness is 0.6. It is 5 to 0.85 mm. If the foamed resin sheet is thicker than 0.95 mm, the heat transfer during the hot plate molding is poor and the foamed resin sheet cannot be molded with high accuracy, and the molding speed is reduced to the level of mass production. : 1 It cannot be accelerated to about 10 seconds per unit), and the synthetic resin film will be overheated and damaged. If the thickness is less than 0.3 mm, the heat insulation of the lid, which is the final molded product, cannot be obtained satisfactorily.

It is necessary to use a synthetic resin film with a thickness of 15 to 80 m. The preferred thickness of the synthetic resin film is 30 to 70 m. The synthetic resin film is useful not only for printing on the lid, which is the final molded product, but also for supporting the strength of the foamed resin sheet forming the lid to suppress cracking. Also helps. If the thickness of the synthetic resin film is more than 80 am, the cost will increase at the mass production level. If the thickness is less than 15 m, the strength required for the synthetic resin film is insufficient, and the heat of molding a hot plate may damage the synthetic resin film itself. When the thickness of the synthetic resin film is 30 to 70 m, the above operation is particularly remarkably exhibited.

The lid, which is the final molded product formed by this method, has excellent heat retention during pouring and not only eliminates the danger of burns when draining, but also details such as the fitting part of the container body. It can be molded with high precision and can be mass-produced. In addition, a lid with a low cost can be provided. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an explanatory diagram showing an enlarged cross section of a laminated sheet. Fig. 2A is an explanatory view of a state in which the laminated sheet is arranged between a hot plate and a mold, Fig. 2B is an explanatory view of a step of softening the laminated sheet, and Fig. 2C is a step of forming a lid. FIG. 2D is an explanatory view of the molded product released from the mold.

FIG. 3 is a schematic perspective view showing a container body and a lid as containers.

FIG. 4 is an enlarged sectional view of a part of the lid.

Figure 5 is an enlarged cross-sectional view of a part of the container. BEST MODE FOR CARRYING OUT THE INVENTION FIG. 3 shows a container A for ready-to-eat food, specifically, a container body 10 and a lid 20 used for “instant fried noodles” and “instant 麵”. The container body 10 is made of expanded polystyrene resin or expanded polypropylene resin having a high expansion ratio (about 10 times), and is not printed on the surface.

The lid 20 is manufactured by the hot plate forming method of the present invention. The lid 20 is made of a synthetic resin film (described later) in which the surface of a foamed resin layer made of foamed polystyrene resin or foamed polypropylene resin is printed with the printed surface inside. It has a laminated structure in which the layers are integrated by heat fusion.

As can be seen from FIGS. 3 to 5, the lid 20 has a fitting projection 21 integrally formed on the peripheral edge thereof and the upper end of the container main body 10. It is mounted on the container body 10 by fitting it into the lid receiving part 11 integrally formed with the part. Then, in order to ensure the mounting state, an engaging ridge 22 is formed inward on the fitting projection 21, and the engaging ridge 22 is formed on the lid receiving portion 11. It is designed to engage with. The lid body 20 has a hollow frame portion 23 for accommodating the lid receiving portion 11 in a fitting shape in an outer peripheral portion thereof, and has a hollow frame portion 23-2. Two diagonal corners are provided with small openings 24 used for pouring and draining water and ventilation, and cut-and-raised pieces 25 for closing the openings, and the product name of the contents is displayed three-dimensionally. A small protrusion 27 is provided at a predetermined position on the inner side of the hollow frame 23. In addition, the entire surface of the lid 20 is printed with the synthetic resin film (display of necessary information on contents, cooking method, etc.). In 26, the printed display of the product name of the contents is largely written.

As shown in FIG. 4, the lid 20 is provided with a synthetic resin film 41 having a printed surface 42 on one side on the surface of the foamed resin layer 3 I and a printed surface 42 on the inner side. The foamed resin layer 31 is integrated by lamination by heat fusion. The synthetic resin film 41 of the lid 20 in the example is heat-sealed to a high-material-density skin layer (not shown) formed on the surface of the foamed resin layer 31.

FIGS. 2A to 2D illustrate the thermoforming method. This hot plate In the molding, a laminated sheet 30 is formed by laminating the synthetic resin film 41 on a foamed resin sheet 3 having a thickness of 0.3 to 0.95 mm and an expansion ratio of 1.5 to 8 times. Used. In other words, in this hot plate molding, as shown in FIG. 2A, the synthetic resin film 41 (see FIG. 1) is placed at an appropriate position between the hot plate 91 and the molding die 92. After disposing the laminated sheet 30 toward the first side, as shown in Fig. 2B, the laminated sheet 30 is sandwiched between the hot plate 91 and the molding die 92, and as shown by an arrow from the molding die 92 side. the laminated one bets 3 0 the air that is blown in by close contact with the hot plate 9 1 1 0 0 to 1 4 0 ^e softens Ri by the and this heating at C approximately of the hot plate 9 1, then 2 As shown in C, the laminated sheet 30 softened by the air (air pressure: 3 to 5 kgcm ² ) blown out from the hot water 91 side is brought into close contact with the mold 92 to laminate a plurality of lids 20. Simultaneous molding at multiple locations on sheet 30. Then, after releasing the mold as shown in FIG. 2D, it is divided into individual lids 20.

At the time of hot plate forming, after the synthetic resin film 41 is placed at an appropriate position between the hot plate 91 and the forming die 92 with the laminated sheet 30 facing the forming die 92 side, the heat is applied. The laminated sheet 30 is sandwiched between the plate 91 and the molding die 92, and the laminated sheet 30 is heated in contact with the hot plate 91 with air blown from the molding die 92 side as shown by the arrow. Thus, the laminated sheet 30 softened by the air blown out from the hot plate 91 side is brought into close contact with the molding die 92, and the plurality of lids 20 are joined to the plurality of laminated sheets 30. It is also possible to adopt a method of simultaneous molding in places. FIG. 1 is a cross-sectional view illustratively showing a laminated sheet 30 provided for the hot plate molding. In the laminated sheet 30, the thickness T 1 of the foamed resin sheet 3 is suitably from 0.3 to 0.95 mm, and the preferable thickness T 1 is from 0.3 to 0.9 mm. . The thickness T of the foamed resin sheet can be set to 0.5 to 0.9 mm, or 0.65 to 0.85 mm. If the foamed resin sheet is thicker than 0.95 mm, heat transfer will be poor during hot plate molding and molding will not be possible with high accuracy, and the molding speed will be increased to maintain the level of mass production. In addition, if the hot plate forming time is extended to transfer heat to the entire foamed resin sheet, the synthetic resin film may be overheated and damaged. .

If the thickness is less than 0.3 mm, satisfactory heat insulating properties will not be obtained for the lid, which is the final molded product. In severe cases, burns may occur. When the thickness T1 of the foamed resin sheet 3 is 0.5 to 0.9 mm, it is possible to forcibly increase the molding speed even if the temperature of the hot plate 91 is not so high. In addition, the heat insulation of the lid 20 as the final molded product was satisfactory, the heat retention during the pouring was kept good, and the hand holding the lid when the water was drained became hot. Will not be possible. The most preferable thickness T1 of the foamed resin sheet 3 is 0.65 to 0.85 mm, and when the thickness is in this range, the above-mentioned effect is remarkably exhibited. The foamed resin sheet 3 has an expansion ratio of 1.5 to 8 times, preferably 1.5 to 6 times. If the foaming ratio of the foamed resin sheet 3 is larger than 8 times, the details in the molding process of FIG. 2C, for example, the fitting piece 21 and the engaging ridge 2 described in FIGS. 2. There is a tendency for details such as small projections 27 to be formed in a sharp and difficult manner. Conversely, if the expansion ratio of the foamed resin sheet 3 is smaller than 1.5 times, satisfactory heat insulating properties cannot be obtained, and a material for molding the lid 20 having the same thickness. Costs are high and product costs rise. In order to have good heat insulation and to be able to mass-produce with high precision and sharpness in detail, it is preferable to set the expansion ratio of the foamed resin sheet 3 to 1.5 to 6 times, preferably 5 times. The degree is the best.

The thickness T2 of the synthetic resin film 41 shown in FIG. 1 is suitably 15 to 80 m. If the synthetic resin film 41 is thicker than 80 m, the synthetic resin film 41 itself becomes expensive, and the mass production level causes a rise in product cost. If the synthetic resin film 41 is thinner than 15 m, the strength required for the synthetic resin film 41 will be insufficient, and the heat generated in the softening process will cause the synthetic resin film 41 to lose its strength. 1 Risk of damage. If the thickness Τ2 of the synthetic resin film 41 is 15 to 80 m, the molding speed can be forcibly increased even if the temperature of the hot plate 91 is not so high. Particularly, when the distance is 30 to 70 m, the above-mentioned action is remarkably exhibited. The use of the synthetic resin film 41 having a thickness T2 of 15 to 80 m also has the following advantages. In other words, before the lid 20 is hot-plated, a synthetic resin film printed on the surface of a foamed resin layer made of foamed polystyrene resin or foamed polypropylene resin is used. It is necessary to create a sheet material for forming the lid 20 by laminating and integrating by heat fusion with the printing surface inside, and in the laminating process, a synthetic resin filler is used. If the thickness T2 of the lum 4 1 is greater than 80 zm, it is too thick, so that heat transfer is poor and it is difficult to increase the laminating speed. If the temperature is increased, the printing surface 42 of the synthetic resin film 41 may be damaged. If the thickness T 2 of the synthetic resin film 41 is less than 15 μm, the strength required for the synthetic resin film 41 will be insufficient, and the laminated sheet 30 will also have satisfactory strength. I can't get it. When the thickness of the synthetic resin film 41 is 15 to 80 m, the laminating speed can be forcibly increased even if the temperature of the heating roll is not so high. In particular, when the distance is 30 to 70 m, the above effect is remarkably exhibited.

In the softening process shown in Fig. 2B, the temperature of the hot plate 91 is set to 100 to 140'C, and the pressure of the air blown from the mold 92 as indicated by the arrow is set to 0.5 to lkg Zcm. ^If the processing time is set to ² and the processing time is set to about 6 seconds, the softening of the laminated sheet 30 proceeds rapidly. At this time, the temperature of the hot plate is too high or the air blowing pressure is too high If the processing time is too long, the back surface of the foamed resin layer 31 of the laminated sheet 30 or the surface of the synthetic resin film 41 may become rough or damaged, and conversely, heat may be generated. If the plate temperature is too low, the air blowing pressure is too low, or the processing time is too short, the laminated sheet 30 will not soften or take time to the extent necessary for later molding. Too much.

In the softening step of FIG. 2B, the temperature of the hot plate 91 is transmitted from the front side of the synthetic resin film 41 to the printing surface 42. Therefore, the printing surface 42 of the synthetic resin film 41 is not easily damaged by roughening. In the molding process shown in Fig. 2C, the pressure of the air blown from the hot plate 91 side as shown by the arrow is SS kg If the thickness is set to Z cm ² , the laminated sheet 30 will surely adhere to the molding die 92, and the lid 20 will be molded quickly and accurately. If the blowing pressure of the air at this time is too high, the air bubbles in the foamed resin sheet 3 are crushed to lower the heat insulating property, and the lid cannot be obtained satisfactorily.If the blowing pressure is too low, There is a possibility that reliable molding, especially the molding of details, may not be performed finely and sharply. Also in this molding process, the temperature of the hot plate 91 is transmitted from the front side of the synthetic resin film 41 to the printing surface 42, so that the printing surface 42 of the synthetic resin film 41 is roughened. It will not damage you.

The lid 20 as a final product obtained by thermoforming the laminated sheet 30 of FIG. 1 has a total thickness of 0.4 to 1.0 mm, preferably. It is desirable to finish to 0.4 to 0.8 mm. Since the laminated sheet 30 may be somewhat compressed due to the hot plate forming step, it can be finished in this thickness range. If the lid 20 is finished to a total thickness of 0.4 to 0.8 mm, the rigidity and lid required for the lid of a ready-to-eat food container that is cooked and poured after cooking When it is fitted and removed from the container body, it has a strength that secures an appropriate elastic force for secure fitting and easy removal.

Since the lid 20 manufactured as described above is obtained by hot-plate forming the laminated sheet 30, the printing location on the printing surface 42 of the synthetic resin film 41 is the same as that of the lid 20. It is accurately set without deviation from the appropriate position of 20. Therefore, the description of the product name, the usage method, the cooking method, etc., and the pattern, etc., displayed on the bulging portion 26 of the lid 20 are also displayed at appropriate positions on the lid 20. Industrial applicability

The hot plate molding method for a food container lid according to the present invention is a method in which a laminated sheet obtained by laminating and integrating a synthetic resin film on a foamed resin sheet is thermoformed and formed. The thickness can be selected from 0.3 to 0.95 mm or 0.3 to 0.9 mm, and the thickness of the synthetic resin film is 15 to 80 πι or 30 to 7 0 um can be selected. The most compact formed by the method of the invention The lid, which is a final molded product, has excellent heat retention during pouring and not only eliminates the danger of burns when draining, but also the printed markings on the synthetic resin film are in the correct position. They are arranged without displacement, and the details such as the fitting part of the container body are precisely formed with high precision. In addition, the lid can be provided at low cost.

Claims

The scope of the claims

(1) Hot-sheet molding a laminated sheet in which a synthetic resin film with a thickness of 15 to 80 m is integrated with a foamed resin sheet with a thickness of 0.3 to 0.95 mm. Hot plate molding method for food container lid.

(2) It is characterized by thermoforming a laminated sheet in which a synthetic resin film with a thickness of 15 to 80 m is integrated on a foamed resin sheet with a thickness of 0.3 to 0.9 mm. Hot plate molding method for food container lid

(3) Hot-plate molding of a laminated sheet in which a synthetic resin film with a thickness of 30 to 70 m is integrated with a foamed resin sheet with a thickness of 0.3 to 0.95 mm. A hot plate molding method for a food container lid.

(4) Thermoforming a laminated sheet in which a synthetic resin film with a thickness of 30 to 70 / m is integrated with a foamed resin sheet with a thickness of 0.3 to 0.9 mm. Characteristic hot plate forming method for food container lid te o