JP2016141438A - Food tray - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a food tray having heat resistance, oil resistance and oil absorption properties, and suitable for a usage of being heated with a microwave oven together with fish or the like placed on a food placing surface in a food storage part, by a food seller and the like or at a household.SOLUTION: A food tray which comprises laminated resin of two layers of an inner surface side resin layer 21 and an outer surface side resin layer 31 is such that: the inner surface side resin layer 21 comprises a resin composition including polypropylene resin and rubber constituent, has a cell structure, and has a skin layer on an adhesive surface to the outer surface side resin layer 31, and on the other hand, has no skin layer on a food placing surface at the other side, and has a plurality of protrusions 14A and 14B on a food placing surface in a food storage part; and the outer surface side resin layer 31 comprises polypropylene resin.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a food tray that can be heated by a microwave while food is placed on a food placement surface.

  Conventionally, polypropylene resin, crystalline polyethylene terephthalate resin (C-PET), filler-filled polypropylene resin, and polymethylpentene are used as food trays that can be heated by a microwave oven while food is placed on the food placement surface. There is a resin tray.

However, when cooking with a conventional resin tray, a problem may occur due to heating of oil flowing out of the food depending on the food. For example, in the case of a foamed resin tray, when cooking in a microwave oven for a long time, the oil flowing out from the food on the tray is heated together with the food and becomes hot, so the tray is deformed or the tray is partially There was a problem of melting.
Non-foamed polypropylene resin trays are heat resistant, so even if the oil that flows out of the food is heated, the tray will not melt, but the resin is not oil-absorbing, so it will flow out of the food. If the oil accumulates in the tray and is provided to the table as it is, the appetite may be impaired.

Japanese National Patent Publication No. 8-501042 Japanese Patent Laid-Open No. 11-292152 Japanese Patent Laid-Open No. 2000-083811

  This invention is made | formed in view of the said point, Comprising: It has heat resistance, oil resistance, and oil absorption property, and it aims at provision of the tray for foodstuffs suitable for heating with a microwave oven with a foodstuff.

  The invention of claim 1 is a food tray having a food container, comprising a laminated resin of two layers of an inner resin layer and an outer resin layer, wherein the inner resin layer contains a polypropylene resin and a rubber component. It consists of a composition, has a cell structure, and the said outer surface side resin layer consists of polypropylene resin, It is characterized by the above-mentioned.

  According to a second aspect of the present invention, in the first aspect, the inner surface side resin layer is characterized in that the polypropylene resin has a melting point of 150 ° C. or higher and the rubber component has a weight average molecular weight of 200,000 or higher.

  The invention of claim 3 is that in claim 2, the resin composition of the inner surface side resin layer is 45 to 65 parts by weight of the polypropylene resin, 10 to 25 parts by weight of the rubber component, and 45 parts by weight or less of the additive component. It is characterized by comprising.

  The invention of claim 4 is characterized in that, in claim 3, the additive component is polyethylene.

  A fifth aspect of the invention is characterized in that, in any one of the first to fourth aspects, the inner surface side resin layer is formed by a supercritical foam molding method.

  The invention of claim 6 is the invention according to any one of claims 1 to 5, wherein the inner surface side resin layer has a skin layer on the adhesive surface with the outer surface side resin layer, and is provided on the food placing surface on the other side. It has no skin layer.

  A seventh aspect of the invention is characterized in that, in any one of the first to sixth aspects, a plurality of protrusions are formed on the food placing surface of the food containing portion.

  According to the invention of claim 1, since the resin layer on the inner surface side that comes into contact with food is made of a resin composition containing a polypropylene resin and a rubber component and has a cell structure, heat resistance, oil resistance and oil absorption are good. Thus, the food is suitable for use in which the food is heated by a microwave oven.

  According to the invention of claim 2, since the melting point of the polypropylene resin contained in the resin composition of the inner surface side resin layer is 150 ° C. or more and the rubber component is made of a weight average molecular weight of 200,000 or more, heat resistance and oil resistance are improved. Further improvement can be achieved.

  According to the invention of claim 3, the resin composition of the inner surface side resin layer is 45 to 65 parts by weight of the polypropylene resin, 10 to 25 parts by weight of the rubber component, and 45 parts by weight or less of the additive component. Heat resistance, oil resistance and oil absorption can be improved.

  According to invention of Claim 4, oil absorption can be further improved by making the additive component contained in the resin composition of an inner surface side resin layer into polyethylene.

  According to the invention of claim 5, since the inner surface side resin layer is formed by the supercritical foam molding method, it can have a fine cell structure, and heat resistance can be further improved.

  According to the invention of claim 6, since the inner surface side resin layer has a skin layer on the adhesive surface with the outer surface side resin layer, it has excellent adhesion at the time of molding, so that the rigidity of the food tray is increased and the handling property is good. In addition, since there is no skin layer on the food placing surface on the other side, the oil that has flowed out of the food placed on the food placing surface can be quickly absorbed by the food placing surface. .

  According to the invention of claim 7, since a plurality of recesses are formed on the food placement surface of the food container, the contact area with the oil that has flowed out of the food placed on the food placement surface increases, Oil that has flowed out of the food can be quickly absorbed by the food placing surface, and oil absorption efficiency can be improved.

It is the perspective view and sectional drawing of one Embodiment of the food tray of this invention. It is 2-2 sectional drawing of FIG. It is 3A partial expanded sectional view of FIG. It is sectional drawing which shows the division | segmentation of the sheet | seat formed by the supercritical foam molding method, and the lamination sheet of an inner surface side resin layer and an outer surface side resin layer.

  The food tray 10 shown in FIGS. 1 to 3 is suitable for food such as fish placed thereon and heated together with the food in a microwave oven. The food tray 10 has a food storage portion 11 that is recessed inward, and food placement surfaces 12 </ b> A and 12 </ b> B are provided on the inner bottom surface of the food placement portion 11.

  The food tray 10 is made of a laminated resin of two layers of an inner surface side resin layer 21 and an outer surface side resin layer 31. The inner surface side resin layer 21 is a layer for absorbing and holding oil spilled from food, and is made of a resin composition containing a polypropylene resin and a rubber component, has a cell structure, and is formed by a supercritical foam molding method. Yes.

The supercritical foam molding method is a known foam molding in which supercritical gas (nitrogen or carbon dioxide) whose temperature and pressure exceed the critical state is dissolved in molten resin, and fine bubbles are generated by sudden pressure reduction. Is the law.
The inner surface side resin layer 21 of the embodiment is formed by extrusion molding using a supercritical foam molding method, and the cellular structure resin sheet 210 as shown in (4-1) and (4-2) of FIG. What was obtained by dividing the thickness into two with a cutting tool 51 such as a cutter is used.

  The inner surface side resin layer 21 shown in (4-2) of FIG. 4 obtained by dividing has a skin layer 22 on one side, and the other surface formed of the divided surface has no skin layer, and the exposed surface 23 of the cell structure. It has become. The skin layer 22 is a dense surface structure formed at the time of supercritical foam molding, can increase rigidity, and is formed on both surfaces of the cellular structure resin sheet 210. The exposed surface 23 of the cell structure is a cut surface (divided surface), and has fine irregularities generated on the surface by cutting a group of fine bubbles on the surface in a plane, and has an oil absorption rate higher than that of the skin layer. Fast surface structure.

  By laminating and adhering the outer surface side resin layer 31 to the surface of the skin layer 22 of the inner surface side resin layer 21 obtained by the division, a laminated body 100 as shown in FIG. It is formed. The laminate 100 can be manufactured by various lamination methods, such as direct lamination in which a thermoplastic synthetic resin sheet is extruded and melted, wet lamination with an adhesive, dry lamination with a hot melt adhesive, heat and super There is heat embossing by sound waves. In particular, the resin material of the outer surface side resin layer 31 is directly applied and laminated on the surface of the skin layer 22 of the inner surface side resin layer 21 obtained by the division, and the outer surface side resin layer 31 is molded by heating and curing. A laminating (extrusion laminating) method is preferable because the two layers can be integrally formed. The thickness of the inner surface side resin layer 21 in the laminate 100 is preferably 0.9 to 1.8 mm, and the thickness of the outer surface side resin layer 31 is preferably 0.2 to 1.0 mm. The food tray 10 can be manufactured by cutting out a rectangle from the long sheet-like laminate 100 and performing known vacuum forming or pressure forming so that the inner surface side resin layer 21 becomes an inner recess.

The polypropylene resin and rubber component in the resin composition of the inner surface side resin layer 21 will be described.
The polypropylene resin preferably has a melting point of 150 ° C. or higher. That is, homopolypropylene or high melting point block polypropylene is preferred. By setting the melting point to 150 ° C. or higher, it is possible to increase the temperature at which the inner surface side resin layer 21 can withstand cooking by a microwave oven.

The rubber component is preferably an oil-absorbing rubber, and examples thereof include a diene rubber and an olefin rubber.
Specifically, styrene-ethylene-butadiene-styrene rubber (SEBS), styrene-butadiene rubber (SBR), styrene-butadiene-styrene rubber (SBS), styrene-ethylene-propylene rubber (SEP), isoprene-butadiene rubber, Examples thereof include styrene-isoprene-butadiene rubber, styrene-isoprene rubber, and ethylene-propylene-diene copolymer rubber (EPDM). In addition, when the rubber component has a low molecular weight, it is not possible to form a foam by a method in which the inner surface side resin layer 21 is depressurized from a supercritical state. Therefore, a rubber component having a weight average molecular weight of 200,000 or more is preferable. In particular, ethylene-propylene-diene copolymer rubber (EPDM) and styrene-ethylene-butadiene-styrene rubber (SEBS) having a weight average molecular weight of 200,000 or more are preferable rubber components.

  The resin composition of the inner surface side resin layer 21 may include polyethylene as an additive component. In particular, low density polyethylene is preferable because it has a high melt tension and is suitable for foam molding and has a low melting point. Further, a high melt tension low density polyethylene is preferable for forming and solidifying bubbles. The melting point of the low density polyethylene is 110 to 115 ° C, and the melting point of the high density polyethylene is about 120 to 140 ° C. When the heating and cooking sheet 10 is heated together with food in a microwave oven, the polyethylene is softened and melted when the heating temperature exceeds the melting point of the polyethylene. The polymer is composed of the polypropylene resin and the rubber component. Since a small amount of polyethylene is melted in the matrix, the affinity between the oil from the food and the rubber component is increased, and the oil absorption by the rubber component can be further enhanced.

  In the resin composition, the polypropylene resin is preferably 45 to 65 parts by weight, the rubber component is 10 to 25 parts by weight, and the additive component is 45 parts by weight or less. The additive component may not be included. If the proportion of the polypropylene resin is increased and the proportion of the rubber component is decreased, the oil absorption is inferior, but the foam cannot be molded. On the contrary, if the proportion of the polypropylene resin is decreased and the proportion of the rubber component is increased, the heat resistance is inferior, but the foam cannot be formed.

  The outer surface side resin layer 31 is a layer that keeps the shape of the food tray 10 and prevents the oil absorbed by the inner surface side resin layer 21 from flowing out to the outside. It is preferable to use a resin or paper that can be used. Examples of the resin include polypropylene resin, polymethylpentene resin, and crystalline polyethylene terephthalate resin. In particular, non-foamed polypropylene resin is a suitable resin having a melting point of 150 ° C. or higher.

  The food tray 10 according to the embodiment has a substantially rectangular planar shape, and a rib 13 that divides the food container 11 into two is provided from the bottom at a central position in the length direction, and the food container Two food placement surfaces 12 </ b> A and 12 </ b> B partitioned by the ribs 13 are formed on the bottom surface of 11. Plural protrusions 14A and 14B are formed on the food placement surfaces 12A and 12B, respectively. One protrusion 14A has a linear rib shape, and the other protrusion 14B has a hemispherical shape. The height of the protrusions 14A and 14B is a range that does not protrude from the upper end of the food container 11, and may be about 1 to 5 mm, for example. The protrusion may have another shape or one type. Furthermore, the food 13 may be provided on the bottom surface of the food container 11 without providing the rib 13.

In the food tray 10, food such as fish is placed on the food placing surfaces 12A and 12B, and is heated with a predetermined range output by a microwave oven. At that time, since the oil flowing out from the food is absorbed and held by the inner surface side resin layer 21, there is little or no oil remaining on the food placing surface 12, 12B, and there is no risk of impairing the appearance, and the taste There is no risk of damage. Further, due to the presence of the plurality of protrusions 14A and 14B, the food placement surfaces 12A and 12B have an increased area in contact with the oil flowing out from the food, and the oil flowing out from the food is quickly removed from the food placement surface 12A. , 12B, and the oil absorption efficiency can be improved. Furthermore, since the inner surface side resin layer 21 and the outer surface side resin layer 31 have heat resistance and the inner surface side resin layer 21 has oil resistance, the inner surface side resin layer 21 absorbs oil flowing out from food. Even if it is heated in such a state, there is no possibility that the food tray 10 will be deformed.

About the laminated body which consists of the said inner surface side resin layer and the said outer surface side resin layer which comprise the foodstuff tray of this invention, each following Example product was created and heat resistance, oil resistance, and oil absorption property were confirmed, respectively.
<Examples 1-5>
A sheet having a thickness of 1.8 mm was formed by the supercritical foam molding method with the composition shown in Table 1 using the following components. After that, the sheet thickness is divided into 0.9 mm by a cutting device, and further cut into a predetermined rectangular shape taking into account the deep-drawing concave portion that becomes the tray, so that it has a skin layer on one side and a skin layer on the other side. The inner surface side resin layers of Examples 1 to 5 without the above were continuously molded. On the surface without the skin layer, the irregularities of the bubble structure were exposed on the surface. The supercritical foam molding apparatus is a tandem single screw extruder, the gas as the foaming agent is carbon dioxide, and the foaming conditions are temperature settings of 175 to 185 ° C.
Polypropylene resin: homopolypropylene, melting point: 162 ° C., product name: EA9, manufactured by Nippon Polypro Co., Ltd. Polypropylene resin: block polypropylene, melting point: 162 ° C., product name: EC 9, manufactured by Nippon Polypro Co., Ltd. Rubber component: EPDM rubber, weight average molecular weight 280,000, propylene content 28 parts by weight, product name: EP57P, manufactured by JSR ・ Additive component: low density polyethylene, melting point: 110 ° C., product name: NUC8042, manufactured by NUC

  Next, while rewinding the sheet roll of the inner surface side resin layer produced in the above process, directly on the extruded product of the outer surface side resin layer (unstretched polypropylene for food tray) made of PP resin. The sheet-like laminates of Examples 1 to 5 were manufactured by laminating and laminating by a direct laminating method in which the thickness was adjusted with a roller. The basis weight of the inner surface side resin layer (foamed layer) and the outer surface side resin layer (non-foamed solid layer) of this sheet-like laminate was 5:18. The production conditions of the laminate are a temperature setting of 200 to 240 ° C. For comparison, the heat resistance, oil resistance, and oil absorption were also confirmed for a single layer (thickness 0.2 mm) of an inorganic filler-containing polypropylene resin that was formed by extrusion-pressing and then vacuum-pressure forming.

<Examples 6 to 10>
The rubber component was changed to the following SEBS rubber, and the other components were the same as in Examples 1 to 5, and a sheet having a thickness of 1.8 mm was formed by supercritical foam molding with the formulation shown in Table 2. Thereafter, the thickness of the sheet is divided into two parts by a cutting device, and further cut into a length of 80 mm × width of 100 mm × thickness of 0.9 mm, thereby having skin layers on one side and no skin layers on the other side. The inner surface side resin layer was manufactured. The supercritical foam molding apparatus is a tandem single screw extruder, the gas as the foaming agent is carbon dioxide, and the foaming conditions are temperature settings of 174 to 185 ° C.
Rubber component: SEBS rubber, weight average molecular weight; 200,000, product name: Kraton G1633, manufactured by Quileton Polymer Japan

Next, while rewinding the sheet roll of the inner surface side resin layer produced in the above process, on the extrusion molded product of the outer surface side resin layer (unstretched polypropylene resin raw material for food tray) made of PP resin The sheet-like laminates of Examples 6 to 10 were manufactured by directly laminating and laminating by a direct laminating method in which the thickness was adjusted with a roller. The basis weight of the inner surface side resin layer (foamed layer) and the outer surface side resin layer (non-foamed solid layer) of this sheet-like laminate was 5:18. The production conditions of the laminate are a temperature setting of 200 to 240 ° C. The inner surface side resin layer of the obtained laminate is configured to place food on the surface where the cell structure without the skin layer is exposed. For comparison, the heat resistance, oil resistance, and oil absorption were also confirmed for a single layer (thickness 0.2 mm) of an inorganic filler-containing polypropylene resin that was formed by extrusion-pressing and then vacuum-pressure forming.

  For heat resistance, 100 cc of water is stored in each of the food trays of each of the examples and comparative examples, heated to 600 W for 3 minutes by a microwave oven to a water temperature of 90 ° C. or higher, and after cooling, the samples of the examples And the presence or absence of shrinkage | contraction of a comparative example product was confirmed, when there was no shrinkage, the heat resistance was ○ (good), and when there was shrinkage, the heat resistance was x (poor). The presence or absence of shrinkage was judged by the dimension before heating and the dimension after heating in the example product and the comparative product. None of the Example product and the Comparative product had shrinkage.

  For oil resistance, each example product and comparative example product are placed on a ceramic heat-resistant dish, and 80 to 100 g of grilled fish (salted grilled salmon) is placed on each example product and comparative product. In a microwave oven, heat for 500 minutes for 3 minutes, and then check the condition on the pan. If the specimen is not deformed, the oil resistance is ◯ (good), and if there is a deformation, the oil resistance is X (Inferior). The example product after heating absorbs and retains oil, oil does not flow out to the part where there is no specimen on the pan, and the specimen is not deformed, so the oil resistance is (It was good. On the other hand, in the comparative example after heating, the oil was not absorbed by the test specimen and the oil was flowing out on the pan, but no deformation was seen in the test specimen, so the oil resistance was ◯ (good). It was.

  The oil absorption is determined by dropping one drop of salad oil on the inner resin layer of each test specimen at room temperature on the upper surface of each Example product and Comparative Example product, 30 seconds later, 1 minute and a half later, and 3 minutes later. The presence or absence of oil droplets was visually judged. The normal temperature here means 20 ° C. ± 15 ° C. of JIS standard Z8703.

  The presence or absence of oil droplets on the test specimen after 30 seconds, 1 and a half minutes, and 3 minutes later is when the oil is not absorbed by the specimen when there are oil drops. Is a state in which oil is absorbed in the specimen. A case where no oil droplet was observed on the upper surface after 1 and a half minutes and 3 minutes later, and a case where an oil droplet remained on the upper surface even after 3 minutes were marked as x. In each example product, oil droplets remained on the test body after 30 seconds, but no oil droplets remained after 1 and a half minutes and after 3 minutes, and therefore the evaluation was good. On the other hand, in the comparative product, oil droplets remained even after 3 minutes and were not absorbed, so the evaluation was x.

  Thus, since the laminated body of Examples 1-10 has heat resistance, oil resistance, and oil absorption, the food tray which shape | molded the laminated body of Examples 1-10 in tray shape is heat resistant, It has oil resistance and oil absorption, and is suitable for heating in a microwave with food.

  The use of the present invention is not limited to food use, and can be expressed as follows. That is, in a resin container having a bottom part formed including a flat surface and a housing part comprising a side wall part extending from the entire outer periphery of the bottom part, a two-layer laminated resin of an inner surface side resin layer and an outer surface side resin layer The inner surface side resin layer is made of a resin composition containing a polypropylene resin and a rubber component, has a cell structure, and the outer surface side resin layer is made of a resin that is not deformed by heating with a microwave oven. This is a resin container. In addition, the inner surface side resin layer is a cellular structure in which a rubber component formed by a supercritical foaming method and a polypropylene resin are dispersed, and is laminated integrally without using an adhesive. Furthermore, the bubble structure is characterized in that the closed cell with the bubble irregularities exposed is a surface on which food is placed.

DESCRIPTION OF SYMBOLS 10 Food tray 11 Food mounting part 12A, 12B Food mounting surface 14A, 14B Protrusion part 21 Inner surface side resin layer 22 Skin layer 23 The exposed surface of the bubble structure which does not have a skin layer 31 Outer surface side resin layer

Claims (7)

In a food tray having a food container,
Consists of two layers of resin, an inner resin layer and an outer resin layer,
The food tray, wherein the inner surface side resin layer is made of a resin composition containing a polypropylene resin and a rubber component, has a cell structure, and the outer surface side resin layer is made of a polypropylene resin.   The food tray according to claim 1, wherein the inner surface side resin layer has a melting point of the polypropylene resin of 150 ° C or higher and the rubber component has a weight average molecular weight of 200,000 or higher.   The resin composition of the inner surface side resin layer is composed of 45 to 65 parts by weight of the polypropylene resin, 10 to 25 parts by weight of the rubber component, and 45 parts by weight or less of the additive component. Food tray.   The food tray according to claim 3, wherein the additive component is polyethylene.   The food tray according to any one of claims 1 to 4, wherein the inner surface side resin layer is formed by a supercritical foam molding method.   The said inner surface side resin layer has a skin layer on the adhesive surface with the said outer surface side resin layer, and does not have a skin layer on the food loading surface on the other side. The tray for foods as described in a term. The food tray according to any one of claims 1 to 6, wherein a plurality of protrusions are formed on the food placement surface of the food storage portion.

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