Tray

Abstract

The present invention provides a tray that allows for easy peeling of the film from the substrate without the need to add a separate component after the tray has been molded. [Solution] The present invention relates to a tray T in which a surface film 2 made of polypropylene resin is heat-fused to a base material 1, wherein the surface film 2 is coated with an ink containing a polyamide resin, and a coating layer 3 of the ink exists between the base material 1 and the surface film 2.

Description

Technical Field

[0001] The present invention relates to a tray having a film layer laminated on a base material.

Background Art

[0002] Conventionally, there is known a tray in which a film is attached to the accommodation surface side of a tray body, and after use, the film is peeled off to recover the tray in a clean state.

[0003] For example, Patent Document 1 describes that at the corner of a tray, a seal is sandwiched between the base material of the tray and the film to form a knob portion, thereby assisting the peeling of the film therefrom.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the tray having the configuration described in Patent Document 1, it is not completed only by laminating and molding the film on the base material, and as a post-process, a step of attaching a seal corresponding to the knob portion to each tray is required, which is understood to be laborious. There is still room for improvement in the structure of the tray for facilitating the peeling of the film from the base material.

[0006] An object of the present invention is to provide a tray capable of easily peeling a film from a base material without providing a separate member after molding the tray.

Means for Solving the Problems

[0007] A first embodiment of the tray according to the present invention is characterized in that a surface film made of a polypropylene resin is heat-fused to a substrate, the surface film is coated with an ink containing a polyamide resin, and a coating layer of the ink exists between the substrate and the surface film.

[0008] A second embodiment of the tray according to the present invention is described as the first embodiment, characterized in that the base material is made of the polypropylene resin.

[0009] A third embodiment of the tray according to the present invention is described as the first embodiment, characterized in that a peripheral edge is formed on the outside of the embankment provided around the outside of the tray, and a recess is formed in the peripheral edge at the corner of the tray.

[0010] A fourth embodiment of the tray according to the present invention is described as the third embodiment, characterized in that the recessed portion is substantially triangular in shape. In this invention, "substantially triangular in shape" includes not only ordinary triangles, but also so-called rounded triangles in which at least one corner of the triangle is rounded, and / or curved triangles in which at least one side of the triangle is curved, and other shapes that include curves that approximate a triangle.

[0011] A fifth embodiment of the tray according to the present invention is described as the third embodiment, characterized in that the recessed portion has a wide, linear shape that extends outward from the center of the tray.

[0012] A sixth embodiment of the tray according to the present invention is described as the third embodiment, characterized in that the peripheral edges of the tray, other than the recessed portions at the corners, are embossed.

[0013] A seventh embodiment of the tray according to the present invention is characterized in that the coating amount of the coating layer is 1 g / m². 2 ~30g / m 2 This is described as the first form, characterized by the following:

[0014] The eighth embodiment of the tray according to the present invention is described as the first embodiment, characterized in that the coating layer is formed by gravure coating.

[0015] The ninth embodiment of the tray according to the present invention is described as the first embodiment, characterized in that the surface film is an unoriented polypropylene resin film.

[0016] A tenth embodiment of the tray according to the present invention is described as the first embodiment, characterized in that the thickness of the surface film is 10 μm to 100 μm.

[0017] An eleventh embodiment of the tray according to the present invention is described as a second embodiment characterized in that the base material is composed of (1) a polypropylene resin with a three-layer structure in which polypropylene resin layers are arranged on both the front and back surfaces of an intermediate layer made of a polypropylene resin to which a filler has been added, or (2) a foamed polypropylene resin.

[0018] In this invention, the term "polypropylene resin" refers to a resin in which the weight of polypropylene resin accounts for more than 50% of the total resin weight excluding fillers.

[0019] Furthermore, in this invention, "filler" refers to all powdered inorganic materials added to resins to impart heat resistance and strength to the base material, and mainly talc, calcium carbonate, and titanium dioxide are used. It is also possible to use powdered eggshells, seashells, etc.

[0020] A first aspect of the method for manufacturing a tray according to the present invention is characterized by comprising: a coating step of coating an unoriented polypropylene resin film with an ink containing a polyamide resin; a sheet creation step of heat-fusing the coated film and a substrate to create a laminated sheet; and a heat molding step of forming a tray from the laminated sheet by heat pressing.

[0021] A second aspect of the method for manufacturing the tray according to the present invention is as described in the first aspect, characterized in that the base material is composed of three polypropylene-based resin layers.

Effects of the Invention

[0022] According to the present invention, there is a coating layer coated with an ink containing a polyamide-based resin between the base material and the surface film, and it becomes possible to easily peel the surface film from the base material without providing a separate member after molding the tray.

Brief Description of the Drawings

[0023] [Figure 1] It is a perspective view of a tray according to a first embodiment of the present invention. [Figure 2] It is a top view of a tray according to a first embodiment of the present invention. [Figure 3] It is a view showing a tray according to a first embodiment of the present invention, where (a) is a front view in the IIIa direction of FIG. 2, and (b) is a cross-sectional view in the IIIb-IIIb direction of FIG. 2. [Figure 4] It is an enlarged cross-sectional view of a tray according to a first embodiment of the present invention, representing the IV part of FIG. 3. [Figure 5] It is a perspective view of a tray according to a second embodiment of the present invention. [Figure 6] It is a top view of a tray according to a second embodiment of the present invention. [Figure 7] It is a view showing a tray according to a second embodiment of the present invention, where (a) is a front view in the VIIa direction of FIG. 6, and (b) is a cross-sectional view in the VIIb-VIIb direction of FIG. 6. [Figure 8] It is a view showing a tray according to a second embodiment of the present invention, where (a) is a front view in the VIIIa direction of FIG. 6, and (b) is a cross-sectional view in the VIIIb-VIIIb direction of FIG. 6. [Figure 9] It is a view showing cross-sections of four types of recessed parts according to a second embodiment of the present invention, where (a) is a cross-sectional view in the IXa-IXa direction of FIG. 6, (b) is a cross-sectional view in the IXb-IXb direction of FIG. 6, and (c) is a cross-sectional view in the IXc-IXc direction of FIG. 6. [Modes for carrying out the invention]

[0024] The embodiments for carrying out the present invention will be described in detail below with reference to Figures 1 to 9. However, the present invention is not limited to the embodiments described here.

[0025] <First Embodiment> <Tray structure> Figure 1 is a perspective view of tray T according to the first embodiment of the present invention, and Figure 2 is a top view of tray T according to this embodiment. Figure 3 is a diagram representing tray T according to this embodiment, where Figure 3(a) is a front view in direction IIIa of Figure 2, and Figure 3(b) is a cross-sectional view in direction IIIb-IIIb of Figure 2. Furthermore, Figure 4 is an enlarged cross-sectional view of tray T according to this embodiment, representing part IV of Figure 3. In Figure 4, the upper layer in the figure represents the inner part of tray T, and the lower layer in the figure represents the outer part of tray T.

[0026] As shown in Figures 1 to 4, the tray T according to this embodiment has a surface film 2 peelably attached to a base material 1. That is, the tray T according to this embodiment is manufactured by molding a plastic sheet base material 1 with a surface film 2 having a coating layer 3 laminated to the food side. The tray T according to this embodiment has storage sections 5 (five in this embodiment) formed by partition sections 4, and a raised edge section (see Figure 3(b)) 6 with an inverted U-shaped cross-section is provided around the outside of the tray, and a peripheral edge section (flange section) 7 is formed on the outside of the raised edge section 6. The peripheral edge section 7 is formed largely at the four corners of the tray T, and in this embodiment, a recessed section 71 is formed at one of the four corners. The user peels the surface film 2 from the base material 1 using the recessed section 71 (for example, by bending the recessed section 71 or pushing it in from below and turning it over, the surface film 2 in that area becomes easier to peel from the base material 1). As described above, in this embodiment, a recess 71 is provided in the flange portion 7, making it easier to peel off the surface film 2 from there. In the present invention, a configuration without the recess 71 is also acceptable. The tray T (or T') according to the present invention is a food tray, which can be used as a lunch box container, to hold ingredients such as meat, vegetables, fruits, and fish, or to hold prepared foods or frozen foods. However, in the present invention, the use and shape of the tray are not limited to the above, and various types can be used as long as they achieve the effects of the present invention. The height of the tray T according to this embodiment is about 30 mm, and the thickness of the tray T (including the base material 1, surface film 2, and coating layer 3) is about 1 mm.

[0027] As shown in Figures 1 to 4, the tray T according to this embodiment is formed by heat-sealing a surface film 2 made of polypropylene resin to a base material 1, wherein the surface film 2 is coated with an ink containing a polyamide resin, and a coating layer 3 of the ink exists between the base material 1 and the surface film 2.

[0028] With this configuration, a coating layer 3 coated with an ink containing a polyamide resin exists between the substrate 1 and the surface film 2, making it possible to easily peel the surface film 2 from the substrate 1 after the tray T is molded without providing a separate component. In other words, the polyamide contained in the coating layer 3 weakens the adhesive force of the heat fusion that occurs between the substrate 1 and the surface film 2, making it easier to peel the surface film 2 from the substrate 1. That is, it prevents excessive fusion at the interface between the surface film and the tray substrate, making it easier to peel the film after molding. Normally, when heat lamination or dry lamination is performed, the lamination strength is strong and it is difficult to peel off, but by printing polyamide that inhibits adhesive force on the inner surface of the surface film 2 (the laminate surface with the substrate 1), it becomes possible to easily peel it off. In this way, the inventors have designed the surface film 2 to be easily peeled off without the processing described in Patent Document 1 (without providing a separate component after the tray is molded) by applying polyamide to the surface film 2.

[0029] If food (prepared foods, bento boxes, frozen foods, etc.) is provided and sold using the tray T according to this embodiment, after consumption, consumers can peel off the soiled surface film 2, and the clean base material 1 can be recovered, crushed, washed, and reused.

[0030] In the tray T according to this embodiment, as shown in Figure 4, the base material 1 consists of three layers, and the intermediate layer contains talc as a filler. The base material 1 according to this embodiment is configured such that a polypropylene filler layer 1ppf is sandwiched between two polypropylene (PP) layers 1pp. In this embodiment, the base material 1 is a PP filler base material and is an extruded laminate (extrusion laminate) consisting of three layers: a polypropylene layer, a polypropylene + talc layer, and a polypropylene layer. The talc makes up 30% of the total sheet. In the present invention, in addition to talc, the filler can be appropriately selected and used from calcium carbonate, titanium dioxide, or powdered eggshells or seashells, etc. Note that the material of the base material 1 according to the present invention is not limited to polypropylene resin, but may be made of pulp mold, for example.

[0031] In this embodiment, as described above, the completed molded tray T consists of, in order from the outside to the inside of the tray T, a base material 1, a coating layer 3, and an unstretched polypropylene resin film 2, as shown in Figure 4.

[0032] In the present invention, the composition of the base material 1 is not limited to the above, and the base material 1 may be composed of (1) a polypropylene resin with a three-layer structure (filler PP) in which polypropylene resin layers are arranged on both the front and back surfaces of an intermediate layer made of polypropylene resin with filler added, or (2) a foamed polypropylene (foamed PP) resin. When using foamed PP, it is desirable to provide a PP layer as an adhesive layer between it and the surface film layer.

[0033] In the tray T according to this embodiment, the surface film 2 is an unoriented polypropylene (CPP) resin film. However, this is not limited to the present invention, and a uniaxially oriented polypropylene resin film may also be used, but it is preferable to use a CPP film due to its ease of stretching. In this embodiment, the thickness of the unoriented polypropylene resin film is about 50 μm.

[0034] For the effects of the present invention to be achieved, the thickness of the surface film 2 is preferably 10 μm to 100 μm. More preferably 40 μm to 60 μm. The thickness of the surface film 2 can be designed considering factors such as ease of stretching. If the thickness of the surface film is less than 10 μm, there is a risk that the film will tear during molding or when peeling off the surface film after consumption.

[0035] Furthermore, if the thickness of the surface film exceeds 100 μm, the rigidity of the film increases, which may result in poor shapeability during molding.

[0036] In this embodiment, the surface film 2 is formed by gravure coating (gravure printing) twice. The number of gravure coatings is not limited to this; it may be done once if it achieves the effects of the present invention, but two times is preferred.

[0037] In this case, if only one coating is applied, the film stretches at the corners during molding, causing the ink coating layer at the interface to crack moderately (or the coating layer 3 to become thinner). This reduces the effect of hindering adhesion, allowing the surface film 2 and the substrate 1 to adhere firmly (directly), and making it difficult for the surface film 2 to peel off the substrate 1. Therefore, by applying two coatings (or increasing the amount of coating applied in one coat), the adhesive strength between the film layer and the tray substrate is adjusted to a level where it can be peeled off after molding.

[0038] In this invention, it is permissible to coat a narrower area of ​​the surface film 2 rather than the entire surface. When it is necessary to narrow the area in this way, the printed polyamide may be stretched and thinned at the corners of the bottom of the tray during molding, which can reduce its peelability, so two or more coats are preferable.

[0039] In this invention, the coating method is not limited to gravure coating, but gravure coating is preferred because it allows for easy adjustment of the coating amount. To achieve the effects of this invention, the coating amount of the coating layer 3 is preferably 1 g / m². 2 ~30g / m 2 Alternatively, the coating amount of coating layer 3 is preferably 7 g / m² of wet coating per application. 2 (Dry 2g / m 2 ~3g / m 2 In this embodiment, the ink of the coating layer 3 formed by printing on the surface film 2 is a polyamide-based transparent ink, which is NT-2000 from Sakata Inx Corporation. The coating (printing) can be done in a solid or halftone pattern.

[0040] <Manufacturing method> The tray T according to this embodiment is manufactured by a manufacturing process that includes a coating step of coating an unstretched polypropylene resin film with an ink containing a polyamide resin, a sheet creation step of heat-fusing the coated film and a substrate 1 consisting of three polypropylene resin layers to create a laminated sheet, and a heat molding step of molding the tray T from the laminated sheet by heat pressing.

[0041] A laminated sheet is created by gravure-coating a CPP film with ink and heat-fusing it with a PP filler substrate. This molded sheet is then heated and pressed in a tray molding machine. In this embodiment, the heating temperature is approximately 400°C, and the actual temperature applied to the sheet is approximately 180°C. In this invention, this temperature may vary depending on the material, shape, and ambient temperature. The tray T can be molded by pressing it between an upper mold and a lower mold.

[0042] In this invention, the recessed portion can take on various shapes.

[0043] <Second Embodiment> Figure 5 is a perspective view of a tray according to the second embodiment of the present invention, and Figure 6 is a top view of the tray according to this embodiment. Figure 7 is a diagram representing the tray according to this embodiment, where Figure 7(a) is a front view in direction VIIa of Figure 6, and Figure 7(b) is a cross-sectional view in direction VIIb-VIIb of Figure 6. Figure 8 is a diagram representing the tray according to this embodiment, where Figure 8(a) is a front view in direction VIIIa of Figure 6, and Figure 8(b) is a cross-sectional view in direction VIIIb-VIIIb of Figure 6. Figure 9 is a diagram representing the cross-sections of the three types of recesses according to this embodiment, where Figure 9(a) is a cross-sectional view in direction IXa-IXa of Figure 6, Figure 9(b) is a cross-sectional view in direction IXb-IXb of Figure 6, and Figure 9(c) is a cross-sectional view in direction IXc-IXc of Figure 6. Among the elements constituting the tray T' according to this embodiment, those having similar functions are denoted by the same reference numerals as in the above embodiments, and their descriptions are omitted. The cross-sectional indicator lines in Figures 9(a) to 9(c) pass through the central axis at the peripheral edge 7 of the corner.

[0044] In this embodiment, as in the first embodiment, the tray T' is heat-fused to the base material 1 with a surface film 2 made of polypropylene resin, the surface film 2 is coated with an ink containing a polyamide resin, and a coating layer 3 of the ink exists between the base material 1 and the surface film 2.

[0045] The tray T' according to this embodiment is substantially rectangular in top view, and three of the four corners of the peripheral edge 7 have recesses 71A, 71B, and 71C, each having a different shape. The user peels the surface film 2 from the base material 1 by using these recesses 71A, 71B, and 71C (for example, by bending the recesses 71A, 71B, and 71C or by pushing them in from below and turning them over, making it easier to peel the surface film 2 from the base material 1 in that area). Thus, in this embodiment, by providing the following recesses 71A, 71B, and 71C at the corners of the peripheral edge 7, it is made easier to peel the surface film 2 from there.

[0046] As shown in Figure 6, the recessed portion 71A is approximately triangular in shape when viewed from above, and has a recess as shown in Figure 9(a).

[0047] As shown in Figures 6 and 9(b), the recessed portion 71B is a wide, linear recess that extends outward from the center of the tray T'.

[0048] As shown in Figure 6, the recessed portion 71C is approximately triangular in shape when viewed from above, and as shown in Figure 9(c), it has a recess. The peripheral edge 7 other than the recessed portion 71C at the corner of the tray T' is embossed in a grid pattern. This configuration provides an anti-slip effect and allows for adjustment of peel strength. Although the embossing is grid-like, the present invention is not limited to this shape. That is, in this embodiment, the embossing is performed using a knurled grid-like mold, but the present invention is not limited to this, and any shape other than grid-like may be used. Note that the knurling is performed before the recessed portion 71C is created, so the surface of the recessed portion is smooth. In this embodiment, the embossing of the flange portion (corner of the peripheral edge 7) is such that the parts that appear grid-like when viewed from above are recessed on the lower side, so that the apex of the pyramid is at the same level as the plane. Furthermore, the embossing process using the knurling may be applied over the entire circumference of the peripheral edge 7 (without or in combination with the indentation).

[0049] In this embodiment, one recess of a different shape is formed in each of the three corners, but the present invention is not limited to this, and one tray may have one type of recess formed in one to four corners, or two or three types of recesses may be combined and formed in two to four corners of one tray.

[0050] <Other> The present invention is not limited to the embodiments described above or the modifications mentioned in various places, and can be modified or altered as appropriate without departing from the technical spirit of the present invention. [Explanation of Symbols]

[0051] T, T' Tray 1 Base material 1 pp polypropylene layer 1 ppf polypropylene filler layer 2. Surface film 3 Coating layer 4. Partition section 5. Storage Area 6. Embankment 7 Peripheral area 71, 71A, 71B, 71C recessed area

Claims

1. A tray in which a surface film made of polypropylene resin is heat-fused to a base material, The surface film is coated with an ink containing a polyamide resin. A tray characterized in that a coating layer of the ink exists between the substrate and the surface film.

2. The tray according to claim 1, characterized in that the base material is made of the polypropylene resin.

3. A peripheral edge is formed on the outer side of the embankment portion provided around the outside of the tray. The tray according to claim 1, characterized in that a recess is formed at the corner of the tray on the peripheral edge.

4. The tray according to claim 3, characterized in that the recessed portion is substantially triangular in shape.

5. The tray according to claim 3, characterized in that the recessed portion has a wide, straight shape extending outward from the center of the tray.

6. The tray according to claim 3, characterized in that the peripheral edges of the tray, other than the recessed portions at the corners of the tray, are embossed.

7. The amount of coating in the aforementioned coating layer is 1 g / m². 2 ~30g / m 2 The tray according to claim 1, characterized in that it is the same as the present invention.

8. The tray according to claim 1, characterized in that the coating layer is formed by gravure coating.

9. The tray according to claim 1, characterized in that the surface film is an unoriented polypropylene resin film.

10. The tray according to claim 1, characterized in that the thickness of the surface film is 10 μm to 100 μm.

11. The tray according to claim 2, characterized in that the base material is composed of (1) a polypropylene resin with a three-layer structure in which polypropylene resin layers are arranged on both the front and back surfaces of an intermediate layer made of polypropylene resin with filler added, or (2) a foamed polypropylene resin.

12. A method for manufacturing trays, A coating process in which an unstretched polypropylene resin film is coated with an ink containing a polyamide resin, A sheet creation process involves heat-sealing the coated film and the substrate to create a laminated sheet. A heating and molding process in which the laminated sheets are heated and pressed to form a tray, A method characterized by including the following.

13. The method according to 12, characterized in that the substrate consists of three polypropylene resin layers.

Images