JP2011093562A - Resin-made tray - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin-made tray having a shape which enables it to be hardly cracked even when mistakenly dropped and a shock is applied to its corner part. <P>SOLUTION: The resin-made tray is square in plan view, and its corner part is formed in an arc shape. A thick-walled part is provided outwardly on an upper part from the 1/2 height at a side of the corner part, the maximum wall thickness of the thick-walled part is 1.5-2.5 times the maximum wall thickness of a lower part from the 1/2 height, and the thick-walled part is formed in a range of the at least 45° in central angle of the arc. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin tray. More specifically, the present invention relates to a resin tray having a shape that is not easily damaged when an impact such as dropping is applied to a corner portion.

Resin trays are lightweight, easy to mold, and available at a relatively low cost, so they are often used for group meals, canteens, and the like.
Since the resin tray is made of resin, it has the property of being easily broken when an impact is applied. In particular, cracks often occur due to impacts when dropped, and the broken trays are discarded without being able to withstand subsequent use for reasons such as safety in strength and deterioration in aesthetics.

  Recently, there have been many occasions where recycled resin is used due to environmental reasons and the like. However, there are more cases in which trays using recycled resin break when falling.

The present invention identifies the occurrence of cracks that occur when dropped due to the occurrence of cracks from the corners due to impacts on the corners, and develops a resin tray that is less likely to break even if accidentally dropped. As a result of earnest efforts, the present invention has been achieved.
The present invention provides a resin tray having a shape that is difficult to break even if it is accidentally dropped and an impact is applied to a corner.

  The present invention is a resin tray having a square shape in plan view and corners formed in an arc shape, and is thicker outward from a height ½ at the side of the corners. The maximum thickness of the thick portion is 1.5 to 2.5 times the maximum thickness below the height ½, and the thick portion has a central angle of 45 ° of the arc. A resin tray formed in the above range is provided.

  The present invention provides a resin tray having a shape that is difficult to break even if it is accidentally dropped.

It is a top view which shows an example of the resin-made trays of this invention. It is a front view of the resin tray of FIG. It is A-A 'sectional drawing in FIG. It is the schematic which shows the position where a thick part is formed in the resin-made trays of this invention. It is the schematic which shows a mode when multiple resin trays of this invention are loaded. It is a figure explaining a drop impact test method.

  The present invention provides a resin tray having a square shape in plan view and a corner portion formed in an arc shape, and outwardly above the height ½ at the side portion of the corner portion. A thick portion is provided, the maximum thickness of the thick portion is 1.5 to 2.5 times the maximum thickness below the height ½, and the thick portion of the arc This is a resin tray formed with a central angle of 45 ° or more.

  The shape of the resin tray of the present invention is rectangular in plan view. The shape may be a square or a rectangle. It is preferable that the four corners of the tray have an arc shape from the viewpoint of aesthetic appearance and ease of handling. Although there is no restriction | limiting in the magnitude | size of the circular arc shape of a corner | angular part, It is preferable to set it as about 20-80 mm by a curvature radius (R).

  In the resin tray of the present invention, the thick portion provided outward in the side portion of the corner portion is a position above 1/2 of the side height, preferably a position above 1/3. It is preferable to provide in. When a flange portion is provided on the outer side of the upper edge in order to facilitate transportation and loading on the resin tray, the portion excluding the flange portion is referred to as a side portion.

  In the case of molding a tray with resin, if a thick portion is partially formed, molding defects such as sink marks, warpage, and welds are likely to occur, so that the thick portion is not partially formed. In consideration of such molding characteristics, the present invention sets the maximum thickness of the thick portion formed above the height ½ at the corner of the present invention to the maximum thickness below the height ½. The thickness is 1.5 to 2.5 times, preferably 1.7 to 2.3 times. Within this range, the problem of molding defects does not occur. In the present invention, the thickness of the side portion means a measured thickness perpendicular to the cross-sectional center line of the side portion.

  The thick portion of the present invention is desirably formed in the range of 45 ° or more, preferably in the range of 45 ° to 90 °, of the arc of the corner of the resin tray.

  The size of the thick part to be formed depends on the size of the resin tray, but in the range satisfying the above conditions, the absolute value is, for example, about 4 to 9 mm in the vertical direction along the side surface center line, in the horizontal direction It is preferable that it is about 3-8 mm.

The present invention will be specifically described below with reference to the drawings.
FIG. 1 is a plan view showing an example of a resin tray of the present invention. The tray 1 has a rectangular shape in plan view, and the corner 2 has a shape drawing an arcuate curve. The tray 1 has a side portion 3 that rises upward from the bottom. A thick portion 4 is formed on the side portion 3 of the corner portion 2. In addition, the tray 1 is provided with a flange portion 5 on the outer side of the upper edge to facilitate transportation and loading on the resin tray, and ribs are provided for stability when the tray is loaded and for preventing over-adhesion. A plurality of 6 are provided. In order to prevent the bottom surface of the tray from being rubbed with a table or the like, a thread tail 7 is provided at the bottom surface corner of the tray.

  FIG. 2 is a front view of the tray 1 shown in FIG. From FIG. 2, it can be seen that the thick portion of the present invention is provided outward from the height ½ on the side portion of the corner portion.

  FIG. 3 is an enlarged view of a cross-sectional view of A-A ′ in the tray 1 of FIG. 1. It can be seen more specifically from FIG. 3 that the thick portion is provided. The thickness a of the thick portion is preferably 1.5 to 2.5 times the maximum thickness b below the height ½.

  FIG. 4 is a schematic diagram showing a preferable range in which the thick portion is provided in the resin tray 1 of the present invention. In the central part of the corner, it is preferable that the thick part is provided so that the central angle c of the arc is 45 ° or more, preferably 45 ° to 90 °.

  FIG. 5 is a schematic view showing a state in which the resin trays of the present invention are stacked. FIG. 5 shows that the inner surface of the side portion of the lower tray is in contact with the outer surface of the thick portion of the upper tray when stacked. When the resin trays of the present invention are stacked, the tray provided with a plurality of ribs on the outer side of the side of the tray so that the inner surface of the side of the lower tray does not contact the outer surface of the thick part of the upper tray is On the other hand, as shown in FIG. 5, the side inner surface of the lower tray is in contact with the outer surface of the thick part of the upper tray, as shown in FIG. A resin tray is also one of the preferred embodiments of the present invention.

  There is no restriction | limiting in particular in resin which forms the tray of this invention, If it is a thermoplastic resin normally used for resin-made trays, it can select suitably and can be used. Since many accidents caused by falling occur particularly in polyester resins, the present invention is particularly effective for polyester resin trays. Examples of the polyester resin include polyethylene naphthalate, polyethylene terephthalate, and polybutylene terephthalate. Particularly effective for recycled polyester resin.

1. Production of resin tray (1) Resin tray I (Example)
Using a recycled product of resin polyethylene naphthalate, a resin tray having a size of 370 × 270 × 18 mm and a corner side wall thickness of 2.2 mm was produced.

(2) Resin tray II (comparative example)
In the resin tray I, a resin tray II having a conventional shape was produced in the same manner as the resin tray I except that the corner portions were not provided with thick portions and the side portions had a uniform thickness.

2. Resin tray drop impact test For the resin tray I and the resin tray II produced above, on a smooth plate standing at an inclination of 80 ° to the horizontal on the concrete surface as shown in FIG. The resin tray was placed face down, dropped from a predetermined height, and visually observed whether or not it was cracked.
For one test tray, the drop height is increased to 30 cm, 50 cm, 70 cm, 90 cm, 130 cm, 150 cm, and 170 cm in order, and the drop is repeated until the crack can be confirmed while observing whether it is broken at each drop. It was.
Table 1 below shows the results of 25 impact tests on resin trays I and II.

3. Drop Impact Test As can be seen from Table 1, the 25 resin trays of the present invention were not broken even at 170 cm, but the conventional resin trays were all cracked at a height of up to 110 cm.
From this, in the resin tray of this invention, the effect that it is hard to break with respect to a drop impact has appeared notably.

The present invention provides a resin tray having a shape that is difficult to break even if it is accidentally dropped.
By implementing the present invention, it is possible to omit not only the shape that is difficult to break even when dropped, but also the ribs that are normally provided on the resin tray.

1. Tray 2. Corner 3. Side 4 4. Thick part 5. Flange part Rib 7. Itoshiri8. Plate 9. Concrete a. Thickness b. Thickness c. Central angle

Claims (5)

  This is a resin tray having a square shape in plan view and corners formed in an arc shape, and a thick part is provided outward from a height ½ at the side of the corner. The maximum thickness of the thick portion is 1.5 to 2.5 times the maximum thickness below the height ½, and the thick portion is in the range of 45 ° or more of the central angle of the arc. Resin tray formed.   The length of the said thick part is 3-8 mm in a horizontal direction, The resin-made trays of Claim 1 characterized by the above-mentioned.   The resin tray according to claim 1, wherein the resin is a polyester-based resin.   4. The resin tray according to claim 3, wherein the polyester resin is a recycled product.   The resin-made tray according to any one of claims 1 to 4, wherein a rib-like object is not formed on the outer side of the tray.

Images