JP2006315741A - Water-proof paper tray - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper tray showing a superior molding characteristic, capable of attaining a sealed seal, a barrier characteristic and a superior heat-resistance and water-proofness that is used for distributing and storing foods or the like. <P>SOLUTION: This paper tray (B) has a laminated member (A) formed by a sheet molding method in which an inner resin layer (2) composed of thermoplastic resin overlies the inner surface of a paper (1) having an extending characteristic having some corrugated wrinkles (5) in advance formed in at least one direction and an outer resin layer (3) composed of thermoplastic resin overlies the outer surface of the paper (1). This tray is characterized in that the outer resin layer (3) is formed of a thermoplastic resin having a high melting point. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper tray. More specifically, the present invention is used for distributing and storing foods and the like, has good moldability, can be hermetically sealed, has a barrier property, and has heat and water resistance. The present invention relates to a paper tray having excellent properties.

  Traditionally, trays that contain fresh food products such as meat, vegetables, fresh fish, processed foods such as lunch boxes, prepared dishes, frozen foods, confectionery, noodles, and industrial products are easy to mold and mass-produced. Plastic trays have been used in large quantities because they can be manufactured at low cost. As these plastic trays, for example, a polystyrene foam tray obtained by molding foam polystyrene beads or pressing a foam polystyrene sheet, a polypropylene tray, a polyethylene terephthalate tray, a polyvinyl chloride tray, etc. are widely used. ing.

  However, the plastic tray has a high environmental load at the time of disposal, for example, when it is landfilled, it remains in the ground without being decomposed semi-permanently. Damage to the incinerator and difficulty of complete combustion, especially those using polyvinyl chloride, caused problems such as the generation of highly corrosive hydrogen chloride gas and dioxin gas.

  Therefore, in consideration of environmental problems, recycling problems, and resource saving, pulp mold trays that are formed of pulp or a material mainly composed of pulp have been used. This tray made of pulp mold has a high degree of freedom in the shape of the container, but the productivity is low, and it is difficult to provide sufficient water resistance and oil resistance often required for food trays. There was a cost increase.

  As a method for obtaining a tray mainly composed of pulp other than the pulp mold, a method is known in which a base sheet mainly composed of pulp such as paperboard is press-molded under heating. In this method, a base sheet with a ruled line previously placed between a male and female mold is loaded and press-molded by hot pressure. Such a press molding method has a very high productivity because a molded body can be obtained by a single press. However, unlike resins and metals, a substrate sheet mainly composed of paper pulp is generally poor in stretchability, spreadability, stretchability, and the like. Therefore, if deep press molding is performed in order to mold a tray having a certain depth, the base sheet cannot withstand the stretching and may break.

  Therefore, when ordinary paperboard or the like is used as a base material, only a molded tray having a little depth such as a so-called paper plate can be produced, and the shape of the obtained tray is very limited. Even if breakage does not occur, it is difficult to create a step in the crease portion of the ruled line portion or to smooth the tray surface. In addition, when there is a step at the container edge of the tray, there is a gap for the step when a lid is attached or when sealing with a film or the like. It was. Furthermore, the breaking point starting from the paper fold is also the cause of lowering the strength of the tray.

In order to solve such a problem, a proposal for improving a paper elongation, providing a molded paper tray having a flange portion having a high degree of freedom in shape, a high sealing property, and an excellent barrier property (for example, Patent Document 1). See). Specifically, various sheets are obtained by heating a laminate in which a thermoplastic resin layer is laminated on an unevenness-formed surface of stretchable paper in which line-shaped unevenness is previously formed in at least one direction from the thermoplastic resin surface. It is a molded paper tray having a flange portion produced by a molding method. Furthermore, in the case of this molded paper tray, water resistance is imparted by laminating polyethylene resin (PE) on the outer surface side.

Prior art documents are shown below.
JP 2003-137260 A

  As described above, by using a stretchable paper and providing a thermoplastic resin layer on the inner surface side of the paper tray, the flange portion of the molded paper tray produced by sheet molding has improved smoothness. Sealing with a cover material certainly improves the sealing performance, and can be used without problems if used in a dry environment. Moreover, it is common to provide water resistance by laminating a low density polyethylene resin (LDPE) also on the outer surface side so that it can be used for applications requiring water resistance.

  However, simply laminating low-density polyethylene resin (LDPE) on the outer surface side of the paper melts the low-density polyethylene resin (LDPE) due to the heat generated when the paper tray is molded, and the water vapor in the paper A number of pinholes are open to escape through the low density polyethylene resin (LDPE). As described above, there is no problem if the paper tray is used in a dry environment, but when the paper tray gets wet, water is absorbed from the pinhole in 1 to 2 minutes, and the strength, hygiene, and aesthetics are impaired.

  Further, if heating is suppressed during molding and the low-density polyethylene resin (LDPE) on the outer surface side is not melted, the deposition area is small, and a part of the low-density polyethylene resin (LDPE) layer floats in the air and is easily broken. . Furthermore, the thermoplastic resin layer on the inner surface side is not sufficiently plastically modified, and the paper tray may be distorted after molding.

  The present invention is intended to solve such problems of the prior art, and is used to distribute and store foods, etc., has good moldability, can be hermetically sealed, and has barrier properties. It has an object to provide a paper tray having excellent heat resistance and water resistance.

  The present invention has been made in order to solve the above-mentioned problems, and the invention according to claim 1 of the present invention has stretchability in which an uneven ridge (5) is previously formed in at least one direction. A laminate (A) in which an inner resin layer (2) made of thermoplastic resin is laminated on the inner surface of paper (1), and an outer resin layer (3) made of thermoplastic resin is laminated on the outer surface of the paper (1). Is a paper tray (B) formed by a sheet molding method, wherein the outer surface resin layer (3) is formed of a high melting point thermoplastic resin. .

  The invention according to claim 2 of the present invention is the paper tray (B) having water resistance according to claim 1, wherein a thermoplastic resin having a low melting point is provided between the paper (1) and the outer resin layer (3). It is a paper tray having water resistance, characterized in that a thermal adhesive resin layer (4) is provided.

  The invention according to claim 3 of the present invention is the paper tray (B) having water resistance according to claim 1 or 2, wherein a part of the inner surface resin layer (2) is made of a thermoplastic resin having gas barrier properties. The paper tray having water resistance according to claim 1 or 2, wherein the paper tray has water resistance.

The invention according to claim 4 of the present invention is the paper tray (B) having water resistance according to any one of claims 1 to 3, wherein the sheet forming method is a pressure forming method, a vacuum forming method, a vacuum pressure forming method. It is a paper tray having water resistance, characterized in that it is a molding method of either a method or a press molding method.

  The paper tray having water resistance according to the present invention has an inner surface resin layer made of a thermoplastic resin laminated on the inner surface of a stretchable paper in which uneven ridges are previously formed in at least one direction, and the paper In a paper tray formed by forming a laminate in which an outer surface resin layer made of a thermoplastic resin is laminated on an outer surface by a sheet molding method, the outer surface resin layer is formed of a high melting point thermoplastic resin, and the paper and the outer surface resin layer Is provided with a thermoadhesive resin layer made of a thermoplastic resin having a low melting point, and a part of the inner surface resin layer is a film made of a thermoplastic resin having a gas barrier property. It can be sealed, has barrier properties, and has excellent heat resistance and water resistance.

  An embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a side sectional view showing one embodiment of a layer structure of a laminate (A) used for a paper tray (B) having water resistance according to the present invention, and FIG. 2 is a water resistance according to the present invention. FIG. 3 is a side cross-sectional view showing another embodiment of the layer structure of the laminate (A) used for the paper tray (B) having water, and FIG. 3 is used for the paper tray (B) having water resistance according to the present invention. FIG. 4 is a partial plan view showing a state in which concave and convex ridges (5) are formed on the paper constituting the laminated body (A), FIG. 4 is a sectional view taken along line XX in FIG. 3, and FIG. FIG. 6 is a partial cross-sectional side view showing one embodiment of a water-resistant paper tray (B) according to the present invention, and FIG. 6 shows a laminate (B) used for the water-resistant paper tray (B) according to the present invention. FIG. 7 is a side sectional view for explaining another embodiment of the layer structure of A), and FIG. 7 shows one embodiment of a paper tray (B) having water resistance according to the present invention. FIG. 8 is a perspective view showing a state in which a paper tray (B) having water resistance according to the present invention is covered with a lid (C) and the flange portion (7) is sealed and sealed. .

  As shown in FIG. 1, the layer structure of one embodiment of the water-resistant paper tray (B) according to the present invention has a stretchability in which uneven ridges (not shown) are previously formed in at least one direction. A laminate in which an inner surface resin layer (2) made of a thermoplastic resin is laminated on the inner surface of the paper (1), and an outer surface resin layer (3) made of a thermoplastic resin is laminated on the outer surface of the paper (1) ( A). Using such a laminate (A), a paper tray (B) having water resistance is formed by various sheet forming methods.

  Next, as shown in FIG. 2, the layer structure of the other examples is a thermoadhesive resin layer made of a thermoplastic resin having a low melting point between the paper (1) and the outer resin layer (3). 4) is provided.

  Thus, the laminate (A) used for the paper tray (B) having water resistance according to the present invention has an outer resin layer (3) / paper (1) / inner resin layer (2) or outer resin layer ( 3) In order to make the adhesion between the surface of the paper (1) and the paper (1) more complete, a thermoadhesive resin layer made of a thermoplastic resin having a low melting point (3) and the surface of the paper (1) ( 4) is provided, the outer surface resin layer (3) / thermoadhesive resin layer (4) / paper (1) / inner surface resin layer (2).

  Incidentally, the paper tray (B) having water resistance according to the present invention provides water resistance so as not to absorb water from outside the bottom surface of the paper tray (B). A thermoplastic resin having a melting point is used.

  Further, since the paper tray (B) having water resistance uses the paper (1) having stretchability and does not have a folding ruled line, the flange portion (7) is bent as shown in FIG. There is no such thing, and it is flat and can be hermetically sealed with the lid (C) as shown in FIG. In addition, a film made of a thermoplastic resin having a gas barrier property is used for a part of the inner surface resin layer (2), and a combination with a lid material (C) having a barrier property provides a high sealing property and a barrier property. Thus, a paper tray (B) excellent in heat resistance and water resistance can be produced.

  Next, the paper tray (B) having water resistance can be formed by various sheet forming methods. For example, a pressure forming method, a vacuum forming method, a vacuum / pressure forming method or a press forming method can be used.

  Next, details of each material constituting the laminate (A) used for the paper tray (B) having water resistance according to the present invention, various sheet forming methods for forming the paper tray (B), etc. Explained.

First, the paper (1) is the main body of the laminate (A). If the paper (1) is stretchable, it is a coated ball containing 100% virgin pulp paper and used paper, and a clay coating treatment on one side. Various papers can be used, and the method for imparting stretchability to the paper is not particularly limited. For example, as shown in FIG. 3 and FIG. Paper (1) having stretchability in which is formed in at least one direction can be used. More specifically, for example, a trade name “WAVYWAVY” manufactured by Nippon Paper Industries Co., Ltd. is preferable. The elongation percentage of the paper (1) shows a value of about 20 to 40% in the longitudinal direction and about 10 to 25% in the lateral direction of the conventional paperboard. Although basic weight is not specifically limited, About 50-400 g / m < ² > is preferable. In addition, as a method for imparting stretchability to the paper (1), the paper (1) is sprayed with steam or the like to give flexibility, and then the concave and convex ridges (5) are passed between the forming roller machine and the flat plate press machine. It is possible to use a method of forming.

  Next, the resin used for the inner surface resin layer (2) needs to have functions such as moldability, heat resistance, sealing properties with the cover material (C) to be placed on the paper tray (B), and is mainly thermoplastic. Resin is used. For example, low density polyethylene resin (LDPE), medium density polyethylene resin (MDPE), high density polyethylene resin (HDPE), linear low density polyethylene resin (L-LDPE), polypropylene resin (PP), acid-modified polypropylene resin, Ethylene-propylene copolymer (EP), ethylene-α olefin copolymer, ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methacrylic acid ester copolymer, ethylene -Acrylic acid ester copolymer, ionomer resin, ethylene-vinyl acetate copolymer (EVA), polyethylene terephthalate resin (PET), polyamide resin (Ny), ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol (PVA) ), Polylactic acid, He The resins such as copolymerized polyester having a sealing property alone or laminated to be used.

  The thickness of the inner surface resin layer (2) is not particularly limited, but is preferably about 10 to 400 μm in view of workability, economy and the like.

  Among the thermoplastic resins, a film made of a resin such as ethylene-vinyl alcohol copolymer (EVOH) or polyvinyl alcohol (PVA) having gas barrier properties is used alone or laminated with a film made of another resin. Thus, a paper tray (B) having a barrier property can be produced.

Next, in order to give water resistance so as not to absorb water from the outside of the bottom surface of the paper tray (B), an outer surface resin layer is provided. The resin used for the outer surface resin layer (3) is a pinhole at the time of molding. In order to prevent the generation, a high melting point thermoplastic resin is mainly used. For example, a resin such as a high-density polyethylene resin (HDPE), a linear low-density polyethylene resin (L-LDPE), or a polypropylene resin (PP) can be used alone or in layers.

  Next, in order to make the adhesion between the outer surface resin layer (3) and the paper (1) surface more complete, a thermal adhesive resin layer is provided between the outer surface resin layer (3) and the paper (1) surface. (4) is preferably provided.

  The resin used for the heat-adhesive resin layer (4) is preferably a low-melting thermoplastic resin. For example, low density polyethylene resin (LDPE), ethylene-propylene copolymer (EP), ethylene-α olefin copolymer, ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), Resins such as ethylene-methacrylic acid ester copolymer, ethylene-acrylic acid ester copolymer, ionomer resin, and ethylene-vinyl acetate copolymer (EVA) can be used alone or in layers.

  Next, outer surface resin layer (3) / paper (1) / inner surface resin layer (2), or outer surface resin layer (3) / thermoadhesive resin layer (4) / paper (1) / inner surface resin layer (2 For example, an extrusion lamination method, a sandwich lamination method using the extrusion lamination method, a dry lamination method, a non-solvent dry lamination method, a hot melt lamination method, and a wet lamination method. A known method such as a method can be appropriately used.

  First, the extrusion lamination method involves heating the thermoplastic resin, dissolving it in a cylinder called a cylinder, extruding it by applying pressure with a screw, from a thin slit called a T die at the tip of the cylinder. In this method, the thermoplastic resin dissolved in a curtain shape is extruded into a film shape and then directly laminated on the paper (1) or the like.

  At this time, using the extrusion lamination method, a sandwich lamination method of laminating a base material layer such as paper (1) and the other film layer using a thermoplastic resin such as polyethylene as an adhesive instead of an adhesive. Can also be used.

  Next, the dry lamination method is a method of applying an adhesive on a base material layer such as one paper (1) and laminating it with the other film layer, and includes a coating part, a drying device, and a nip roller part. It consists of a section and an unwinding, winding and tension control system.

  The coating portion generally employs a gravure roll coating method or a reverse roll coating method.

  As the adhesive used in the dry lamination method, laminate adhesives such as polyurethane, polyacrylic, polyester, epoxy, polyvinyl acetate, cellulose, and the like can be generally used.

  As the lamination adhesive, a solvent-type adhesive or a solvent-free adhesive is used. However, when a solvent-free adhesive is used, a drying apparatus is unnecessary, and in particular, a non-solvent dry lamination method and I'm calling.

  In the hot melt lamination method, a hot melt adhesive composed of a heat-melted ethylene-vinyl acetate copolymer (EVA), a wax, a tackifier or the like is applied onto a base material layer such as one paper (1). This is a method of immediately laminating with the other film layer.

  In the wet lamination method, a water-soluble adhesive is applied on a base material layer such as one of the papers (1) and laminated with the other film layer while the adhesive is wet. This is a method of evaporating and adhering.

  As described above, various lamination methods can be used. However, when a single outer resin layer (3) or inner resin layer (2) is provided on paper (1), the thermoplastic resin is directly used. It is preferable to use the extrusion lamination method in view of productivity and cost.

  In addition, when a multilayer film having barrier properties (for example, LDPE / Ny / EVOH / PP, LDPE / EVOH / PP, etc.) is used for the inner surface resin layer (2) or by coextrusion on the outer surface resin layer (3). The produced multilayer film (for example, HDPE / LDPE, PP / LDPE, L-LDPE / LDPE, HDPE / Ny / LDPE, PP / Ny / LDPE, etc.) or a heat-adhesive resin layer (4 In the case of laminating), a sandwich lamination method of laminating via a low density polyethylene resin (LDPE) is preferable in consideration of productivity, cost and the like.

  After heat is applied from the surface of the inner surface resin layer (2) to the laminate (A) thus produced, a pressure forming method, a vacuum forming method, a vacuum pressure forming method, a press forming method, or the like is used. And the paper tray (B) which has a planar flange part (7) as shown in FIG. 7 is produced.

  The pressure forming method, the vacuum forming method, and the vacuum pressure forming method are those in which the laminate (A) is subjected to a secondary forming process, and a heated and softened sheet is provided with a male mold provided with small holes (vent holes) or This is a molding method in which either one of the female molds is used and the molded product is taken out after being brought into close contact with the mold using vacuum or compressed air and cooled. The press molding method uses a pair of male and female press dies and is press-molded by hot pressure. Since a compact is obtained by one press, the productivity is very high. Is the method.

  Thus, when the laminate (A) used for the paper tray (B) having water resistance according to the present invention is molded by the various sheet molding methods, as shown in FIG. 6, the outer surface resin layer (3) and the paper (1) The resin constituting the heat-adhesive resin layer (4) and the inner surface resin layer (2) provided between the surface and the inner surface resin layer (2) is formed only on the convex portion of the uneven ridge (5) before molding. Although not bonded, the resin melts when heated to the melting point of the resin at the time of molding, and adheres to the gap (6) of the concave portion that is flat or shallowly stretched at the time of molding, thereby reducing the bonding area. This increases the adhesion between the uneven ridge (5) surface of the paper (1) and the resin layer surface. In the case where the laminate (A) has the outer resin layer (3) directly laminated on the paper (1) as shown in FIG. 1, it is heated to the melting point of the resin during molding. The same phenomenon occurs, and the adhesion between the uneven ridge (5) surface of the paper (1) and the resin layer surface is stabilized. As described above, the thermoadhesive resin layer (4 ) Is preferred.

  Further, since the paper tray (B) does not have a folding ruled line, the flange portion (7) has a flat shape as shown in FIG. 7, and as shown in FIG. Can be hermetically sealed. Further, as described above, a film made of a thermoplastic resin having a gas barrier property is used for a part of the inner surface resin layer (2), and the combination with the lid material (C) having a barrier property provides a high sealing property and a barrier. A paper tray container product with a sealing lid material having excellent heat resistance and water resistance can be produced.

  The lid material (C) is required to have a heat seal property that completely seals and seals the paper tray (B), and conversely, an easy peel property that can be easily opened when opened.

  First, there are various heat sealing techniques for completely sealing and sealing the paper tray (B). For example, a heat sealing (bar sealing) method, an impulse sealing method, an ultrasonic sealing method, a high frequency sealing method, etc. Among them, the heat seal (bar seal) method is the most common method.

  By the way, low density polyethylene resin (LDPE), medium density polyethylene resin (MDPE), high density polyethylene resin (HDPE), linear low density polyethylene resin (L-LDPE), polypropylene resin (PP), ionomer [ethylene and methacrylic]. Thermoplastic resin partially crosslinked with a metal ion (sodium, zinc, etc.) with an acid], and polyolefins such as ethylene-vinyl acetate copolymer (EVA) generally have excellent heat seal characteristics. Therefore, it is often used as a sealant.

  The sealant of the lid material (C) to be placed on the paper tray (B) having water resistance according to the present invention is required to have performances in which sealing properties and easy peel properties are contradictory. In order to facilitate the opening of the lid (C), various easy-open heat sealing techniques can be applied, but the most common is a lid (C) having a peelable sealant. The technique to use. The peelable lid material (C) has a peeling mechanism at the time of opening: 1) Interfacial peeling type between the paper tray and the lid material, 2) Delamination type between the base material and the sealant of the lid material, and 3) Cohesive failure of the sealant of the lid material Although it can be classified into three types, it is appropriately selected depending on the material of the inner surface resin layer (2) of the paper tray (B). Although it depends on the use of the paper tray container product with a sealing lid, in general, those having an easy peel property are preferred. For example, urethane, ethylene-vinyl acetate copolymer (EVA), and other thermoplastic resins can be used.

  Next, characters / patterns with printing ink are usually provided on the base material constituting the paper tray (B) and the lid material (C). As the printing ink, a coloring material composed of a pigment or a dye that gives color to the ink, a resin that is fixed to a printed material, and the resin are stably dissolved while the coloring material is dispersed and held in fine particles. A vehicle composed of a solvent that retains the dispersibility of the pigments and dyes, the fluidity of the ink, and can transfer the appropriate amount of ink from the printing plate, and further improves the dispersibility of the colorant, develops color, and precipitates. For the purpose of prevention and improvement of fluidity, it is formed from an auxiliary agent such as a surfactant. In particular, the colorant is preferably a pigment having good weather resistance.

  As a printing method for providing the printing ink, for example, a known printing method such as a gravure printing method, a silk screen printing method, a flexographic printing method, and an offset printing method can be used, but copper plating is applied to the surface of an iron cylinder (cylinder). Forming a base, providing a release layer on the copper-plated surface, further copper-plating, and creating a recess (cell) by engraving or corrosion method on the polished copper surface of the surface, A gravure printing method is preferred, in which the printing ink in the cell is transferred to enable colorful printing even with a toned material and has a high appealing effect.

  Hereinafter, the paper tray (B) having water resistance according to the present invention will be described in more detail with specific examples, but the present invention is not limited to these and is applied to a wider range. .

<Example 1>
First, a laminate (A) having the following configuration was prepared as a laminate (A) used for the paper tray (B). PP 20 μm (outside resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: WAVYWAVY (Wavy / Wavy) 275 g / m ² / PP 60 μm (inner surface resin layer).

Next, after slitting the laminate (A) to a desired width, an elliptical paper tray (B) was produced by pressure forming while heating from the PP surface (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 2>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). HDPE 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy Wavy 275 g / m ² / PP 60 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 3>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). L-LDPE 20 μm (outside resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy / Wavy 275 g / m ² / PP 60 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 4>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). PP 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy / Wavy 275 g / m ² / PE ²⁰ μm / (PE / Ny / EVOH / PP) 80 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 5>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). HDPE 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy / Wavy 275 g / m ² / PE ²⁰ μm / (PE / Ny / EVOH / PP) 80 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 6>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). L-LDPE 20 μm (outside resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy / Wavy 275 g / m ² / PE ²⁰ μm / (PE / Ny / EVOH / PP) 80 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 7>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). PP 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy / Wavy 275 g / m ² / PE ²⁰ μm / (PE / EVOH / PP) 60 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 8>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). HDPE 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy / Wavy 275 g / m ² / PE ²⁰ μm / (PE / EVOH / PP) 60 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 9>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). L-LDPE 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy / Wavy 275 g / m ² / PE ²⁰ μm / (PE / EVOH / PP) 60 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 10>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). PP 20 μm / LDPE 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy / Wavy 275 g / m ² / PP 60 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 11>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). HDPE 20 μm / LDPE 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy / Wavy 275 g / m ² / PP 60 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 12>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). L-LDPE 20 μm / LDPE 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy / Wavy 275 g / m ² / PP 60 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated in a microwave oven, even if the contents were blown out, the paper stiffness did not drop and there was no problem with water resistance.

<Example 13>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). PP 20 μm / Ny 20 μm / LDPE 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy Wavy 275 g / m ² / PP 60 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 14>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). HDPE 20 μm / Ny 20 μm / LDPE 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy Wavy 275 g / m ² / PP 60 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

<Example 15>
In Example 1, an elliptical paper tray (B) was produced in the same manner as in Example 1 except that a laminate (A) having the following configuration was prepared as the laminate (A). L-LDPE 20 μm / Ny 20 μm / LDPE 20 μm (outer surface resin layer) / manufactured by Nippon Paper Industries Co., Ltd., trade name: Wavy Wavy 275 g / m ² / PP 60 μm (inner surface resin layer).

  When the paper tray (B) was filled with a liquid and heated with a microwave oven, even if the contents were blown out, the stiffness of the paper did not drop and there was no problem with water resistance.

It is a sectional side view which shows one Example of the laminated constitution of the laminated body used for the paper tray which has water resistance based on this invention. It is a sectional side view which shows the other Example of the laminated constitution of the laminated body used for the paper tray which has water resistance based on this invention. It is a fragmentary top view which shows the state which formed the uneven | corrugated ridge in the paper which comprises the laminated body used for the paper tray which has the water resistance which concerns on this invention. FIG. 4 is a side sectional view taken along line XX in FIG. 3. It is a fragmentary sectional side view which shows one Example of the paper tray which has water resistance based on this invention. It is a sectional side view explaining the other Example of the layer structure of the laminated body used for the paper tray which has water resistance based on this invention. It is a perspective view which shows one Example of the paper tray which has water resistance based on this invention. It is a perspective view which shows the state which covered the cover material on the paper tray which has water resistance based on this invention, and sealed and sealed the flange part.

Explanation of symbols

A ... Laminate B ... Paper tray C ... Lid 1 ... Paper 2 ... Inner surface resin layer 3 ... Outer surface resin layer 4 ... Thermal adhesive resin layer 5 ... Uneven ridges 6 ... Gap 7 ... Flange

Claims (4)

  An inner surface resin layer made of a thermoplastic resin is laminated on the inner surface of a stretchable paper in which uneven ridges are formed in at least one direction in advance, and an outer surface resin layer made of a thermoplastic resin is laminated on the outer surface of the paper A paper tray having a water resistance, wherein the outer surface resin layer is formed of a thermoplastic resin having a high melting point.   2. The paper tray having water resistance according to claim 1, wherein a thermal adhesive resin layer made of a thermoplastic resin having a low melting point is provided between the paper and the outer surface resin layer.   3. The paper tray having water resistance according to claim 1, wherein a part of the inner surface resin layer is a film made of a thermoplastic resin having gas barrier properties.   The water resistance according to any one of claims 1 to 3, wherein the sheet forming method is a pressure forming method, a vacuum forming method, a vacuum pressure forming method, or a press forming method. Paper tray.

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