JP2005053554A - Draw-formed hermetic paper container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a draw-formed hermetic paper container with a flange obtained by drawing a single cardboard base having a thermoplastic resin layer applied on the surface, wherein the flange is smooth, and the container is free from resin burrs both inside and outside the flange, hygienic and attractive. <P>SOLUTION: The draw-formed hermetic paper container 1 is formed by using a blank consisting of a single cardboard base and equipped with radial creases at its corners, drawing it and folding the creases to form wrinkles. The wrinkles formed at a corner of the flange 14 are welded in a welding width 18W smaller than a width 14W of the flange 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a deep-drawn paper container formed from a single paperboard base paper by only pressing, and in particular, a drawn-formed sealing paper in which a sealing lid is sealed to a flange portion provided at the periphery. It relates to the container.

  Conventionally, instead of a plastic container, it is easy to save resources and dispose of it. For this reason, a blank made of a single paperboard with a thermoplastic resin layer on its surface is used, and a deep-drawn tray-shaped paper container is used. It is well known as a draw-formed sealed paper container that seals the contents by sealing with a sealing lid on its flange, and is widely used as a sealed paper container that retains sealing, barrier, and fragrance properties mainly for food applications. It is popular.

  However, in the draw-formed sealed paper container formed by the above technique, the wrinkle part due to the draw-molding remains in the corner of the flange part, and the thickness of the flange part varies, so the sealing lid is sealed to the flange part. At that time, it was difficult to obtain high sealing performance.

  In order to solve the above problems, for example, a paperboard blank having a thermoplastic resin layer laminated on the surface thereof is used to form a deep-drawn paper tray having a flange portion, and the entire flange portion is formed on a smooth surface by ultrasonic processing. There is a manufacturing method of a deep-drawn paper tray (see, for example, Patent Document 1).

The above prior art documents are shown below.
JP 2000-33927 A

  However, in the above prior art, if the entire flange portion of the paper tray obtained by deep drawing is made a smooth surface by ultrasonic processing, the wrinkle portion at the corner of the flange portion becomes a smooth surface, The thermoplastic resin layer on the surface protrudes from both end edges of the flange portion due to heat pressure, and resin burrs are generated at both end edges (inner side and outer side) of the flange portion. This has the problem that it lacks hygiene for food use and lacks appearance as a product.

  The present invention solves the problems of the prior art, and the object of the present invention is to provide a flange portion obtained by drawing a sheet of paperboard having a thermoplastic resin layer on the surface. In a draw-formed sealed paper container, a draw-formed sealed paper container that has a smooth flange part, no resin burr due to the protrusion of the thermoplastic resin layer inside and outside the flange part, and is excellent in hygiene and looks good. It is to provide.

In order to achieve the above object in the present invention, first, in the invention of claim 1, a thermoplastic resin layer is applied to at least one surface of a single paperboard, and radial crease lines are applied to corners thereof. The blank is drawn and formed into a bottom part, a side wall part connected to the bottom part, and a flange part extending continuously to the side wall part and extending horizontally, and the crease line is folded and wrinkled. In the draw-formed sealed paper container in which the portion is formed, the wrinkle portion formed in the corner of the flange portion is welded with a width smaller than the width of the flange portion, and the drawn-formed sealed paper container is provided Is.

  According to a second aspect of the present invention, the position welded with a width smaller than the width of the flange portion is substantially at the center in the width direction of the flange portion and at least inside the side edges. The drawn molded sealed paper container described above.

  In the invention of claim 3, the welded width is in the range of 10 to 80% of the width of the flange portion. It is a container.

  According to a fourth aspect of the present invention, the thickness of the thermoplastic resin layer is in the range of 5 to 40% of the thickness of the paperboard base paper. It is a paper container.

  Furthermore, in the invention of claim 5, after the wrinkle portion of the corner of the flange portion is welded, the entire flange portion is press-worked. This is a molded sealed paper container.

  Since this invention is the above structure, there exist the following effects.

  That is, according to the first aspect of the present invention, the wrinkle portion formed by folding the crease line at the corner of the flange portion is welded with a width narrower than the width of the flange portion. Since it does not come out outside or inside the part, there is no occurrence of resin burrs, hygiene for food use is not lacking, and a drawn molded sealed paper container that looks good as a product can be obtained.

  According to the second aspect of the present invention, the position welded with a width smaller than the width of the flange portion is set at least at the inner side of at least both side edges at the approximate center in the width direction of the flange portion. Extrusion of the thermoplastic resin due to is difficult to come out on both side edges of the flange part, so there is no occurrence of resin burrs on both side edges of the flange part, there is no lack of hygiene for food use, and it looks good as a product There is an effect that it is possible to obtain a drawn molded sealed paper container.

  Further, according to the invention of claim 3, by setting the welded width to a range of 10 to 80% of the width of the flange portion, sufficient strength and sealability of the flange portion by welding can be obtained. In addition, the protrusion of the thermoplastic resin is less likely to occur on both side edges of the flange portion, and therefore, there is no occurrence of resin burrs on both side edges of the flange portion. There exists an effect which can be set as the draw-formed airtight paper container which looks good. If the welded width is less than 10% of the width of the flange portion, sufficient strength of the flange portion will not be obtained, and if it exceeds 80%, excess thermoplastic resin due to welding will be removed from both side edges of the flange portion. Since it will be easy to protrude, it is not preferable.

  Further, as described above, since the welded width is smaller than the conventional one, the welding time and the applied pressure can be reduced, so that the production efficiency can be improved.

Further, according to the invention according to claim 4, by setting the thickness of the thermoplastic resin layer applied to at least one surface of the paperboard base paper to a range of 5 to 40% of the thickness of the paperboard base paper, Adequate strength and sealability of the flange due to welding can be obtained, and the protrusion of the thermoplastic resin is less likely to occur on both side edges of the flange, so that there is no occurrence of resin burrs on both sides of the flange, and therefore food. There is an effect that it is possible to obtain a draw-formed sealed paper container that does not lack hygiene as a use and that also looks good as a product. If the thickness of this thermoplastic resin layer is less than 5% of the thickness of the paperboard, the amount of resin required for welding cannot be obtained, and this causes pinholes (liquid leakage), resulting in sealing properties. Chipping and sufficient strength of the flange portion are not obtained, and if it exceeds 40%, the resin layer becomes too thick, and excess thermoplastic resin due to welding tends to protrude from both side edges of the flange portion and become resin burrs. Therefore, it is not preferable.

  Furthermore, according to the invention according to the fifth aspect, after the wrinkle portion of the corner of the flange portion is welded, the entire flange portion is smoothed by pressing (normal temperature) the entire flange portion. The sealing lid material can be easily sealed to the flange portion, and there is an effect that it is possible to provide a draw-formed sealed paper container excellent in sealing performance (no liquid leakage).

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a perspective view showing the entire drawing-formed sealed paper container of the present invention, and FIG. 2 is a front view of a blank used for the drawn-shaped sealed paper container of the present invention. FIG. 3 is a side view showing an example of the drawing process of the drawn molded sealed paper container of the present invention, and FIG. 4 is a side view showing an example of the welding process of the drawn molded sealed paper container of the present invention. FIG. FIG. 5 is a plan view showing a welded portion formed on the flange portion, and FIG. 6 is an enlarged cross-sectional view showing the welded portion formed on the flange portion. FIG. 7 is a schematic diagram showing a change in the processing state of the wrinkle portion of the flange portion.

  In the present invention, for example, as shown in FIG. 1, a blank made of a single sheet of paperboard is drawn and connected to a rectangular bottom (10) with rounded corners and to each side of the bottom (10). The four side walls (12) and the side walls (12) are connected to the side walls (12), and the horizontally extending corners are rounded rectangular flanges (14). The corners of the flanges (14) Further, the invention relates to a draw-formed hermetic paper container (1) in which a wrinkle portion (14a) folded by a crease line is formed, and a sealing lid (20) is sealed to the flange portion (14), for food use And so on.

  As shown in FIG. 2, the drawing-molded sealed paper container (1) uses, for example, a blank (3) made of rectangular paperboard (30) with rounded four corners. 3) The surface is provided with a thermoplastic resin layer (32), and the broken line portion shown in the inside is a boundary portion corresponding to the bottom portion (10) when drawn, and the vertical and horizontal portions thereof Are portions corresponding to the side wall portion (12) and the outer flange portion (14). With respect to the portions corresponding to these four corners, a radial crease line (16) extending from the center position (15) of the curved portion located at the bottom portion (10) to the outer peripheral edge in the region A is the surface. The outer peripheral edge of this corner is an arcuate curved portion (15a) centered on the curved portion center position (15).

  The blank (3) obtained above is inserted between a male mold (100) and a female mold (200), for example, as shown in FIG. This is a draw-formed sealed paper container composed of a portion (12) and a flange portion (14) that is provided continuously therewith and extends horizontally.

Therefore, in the invention according to the first aspect, for example, as shown in FIG. 4, the wrinkle portion (not shown) at the corner of the flange portion (14) of the draw-molded sealed paper container (1) obtained by the above-described draw molding. Is sandwiched between the ultrasonic horn (50) and the upper edge (62) of the receiving jig (60), pressed, and oscillated, thereby causing wrinkles at the corners of the flange (14) as shown in FIG. A welded portion (18) is formed on the portion (14a) along the flange portion (14). As shown in FIG. 6, the width (18W) of the formed welded portion (18) is a flange. It is characterized by being narrower than the width (14W) of the part (14).

  For example, as shown in the upper part of FIG. 5, the formed welded part (18) may be formed with wrinkle parts (14a) at the upper left and right corners and an upper flange connecting the wrinkle parts (14a). As shown in the lower part, it may be formed only in the wrinkle part (14a) of the corner.

  At this time, the receiving jig (60) is used in which the width (62W) of the upper end portion (62) is narrower than the width (14W) of the flange portion (14).

  In addition to the ultrasonic sealing method of internal heating as shown in FIG. 4, a high frequency sealing method can be applied to the formation of the welded portion (18) depending on the type of resin. Further, as a method by external heating, for example, a bar sealer method, an impulse seal method, or the like can be applied, and can be appropriately selected depending on the type of resin.

  In the invention according to claim 2, for example, as shown in FIG. 5, the position of the welded portion (18) welded to the flange portion (14) is in the width (14W) direction of the flange portion (14). In the middle of both sides, it is assumed to be inside the both side edges. For example, as shown in FIG. 4, the ultrasonic horn (50) and the upper edge (62) of the receiving jig (60) are sandwiched and welded. When the portion (18) is formed, resin burrs due to the overflow of the thermoplastic resin due to this welding are made difficult to occur.

  In the invention according to claim 3, for example, as shown in FIG. 6, the welding width (18W) to be welded is in the range of 10 to 80% of the width (14W) of the flange portion (14). By this range of welding, the flange portion (14) having a sufficient strength and sealability, particularly the corner portion thereof, is obtained, and the resin burr due to the protrusion of the thermoplastic resin is difficult to occur.

  When the weld portion (18) obtained as described above is welded by ultrasonic processing or the like to the wrinkle portion (14a) folded at the crease line by drawing, for example, as shown in FIG. As shown in (b), the thermoplastic resin layer (32) applied to the surface of the paperboard base paper (30) is melted and the wrinkle portion is welded to improve the sealing performance, and the strength of the wrinkle portion (corner). Will increase.

  Furthermore, in the invention according to claim 4, for example, as shown in FIG. 6, the thickness of the thermoplastic resin layer (32) is in the range of 5 to 40% of the thickness of the base paper (10). By setting the thickness of the thermoplastic resin layer (32) within this range, there is no risk of pinholes or resin burrs occurring in the thermoplastic resin layer (32), so that the flange portion (14) due to welding is sufficiently formed. It is possible to obtain a draw-formed sealed paper container that has strength and sealability and does not lack sanitary properties for food use and that also looks good as a product.

  Further, in the invention according to the fifth aspect, after the wrinkle portion at the corner of the flange portion is welded as described above, the entire flange portion (14) is pressed by a press machine (70) as shown in FIG. By pressing the entire flange portion (normal temperature) in this way, the portions other than the welded portion (18) (both ends) of the flange portion (14) shown in FIG. What formed the wrinkle part (14a) of the shape as shown in a) forms a crushed wrinkle part (14a-A) as shown in FIG. 7 (c), and the entire flange part is smooth. As shown in FIG. 1, a sealing lid (20) can be easily sealed on the flange portion (14), and a drawn molded sealed paper container (1) having excellent sealing performance (no liquid leakage). ) Can be provided.

  The material etc. which comprise the draw-formed airtight paper container of this invention are demonstrated below.

  As the paperboard base paper (30) as the main strength material of the drawing-molded sealed paper container (1) of the present invention, for example, ivory, coated ball, card base paper, and the like are used, including cup base paper having good drawability. In addition, the board base paper (30) can be used without any problem by internally adding or impregnating a resin capable of imparting rigidity, water resistance and hot water resistance as a secondary process after the paper making stage or after paper making. However, the paperboard base paper (30) in this case is not limited to the so-called paper type. The basis weight is not particularly limited, but is preferably in the range of 150 to 600 g / m 2 in consideration of drawing suitability and the like. Further, if the density of the paper is ρ ≦ 1 g / cm 3, molding is possible, but considering the smoothness of the flange portion (14), ρ ≦ 0.7 g / cm 3 has cosmetic properties after molding, as shown in FIG. When the level difference (H) of the wrinkle portion (14a) of the flange portion is about 30 μm, it is easy to perform welding and pressing, which is preferable.

  In addition, the provision of the thermoplastic resin layer (32) applied to the surface of the paperboard base paper (30) (the inner surface of the container) enables, for example, heat sealing with the sealing lid material (20) shown in FIG. In addition, paper breakage and tearing during the molding of the draw-formed sealed paper container (1) can be suppressed by absorbing the shearing force by the resin layer (32), and further sealed by the welding process of the wrinkle portion (14a) of the present invention. It improves the performance.

  As the thermoplastic resin layer (32), the protective properties of the contents, in particular, the function of preventing leakage of liquids such as water and exudation, heat sealability with the sealing lid (20), moldability, heat resistance, etc. For example, polyethylene terephthalate resin, polyethylene naphthalate resin, or a mixture thereof, polyolefin resin such as polyethylene resin, polypropylene resin, modified polyolefin resin, polyacrylonitrile resin, polyvinyl chloride resin, ethylene vinyl acetate copolymer In addition to coalescence, polyamide resin, polystyrene resin, polycarbonate resin, polyvinyl alcohol resin, various thermoplastic resin layers, and those obtained by laminating or laminating a film-like material, and the thickness of the film-like or laminate is as described above. From the invention according to item 4, the above paperboard base paper (3 To the thickness of), it is preferably in the range of 10~150μm within its 5-40%.

  Examples of the means for applying the thermoplastic resin layer (32) to the paperboard base paper (30) include, for example, dry laminating method, extruder sand laminating method, coextrusion laminating method, wet laminating method, and the like. However, it is more preferable to perform extrusion lamination by the extruder sand laminating method in which the paper and the thermoplastic resin layer surface easily follow in the drawing, because the sealing property of the drawing-formed sealed paper container of the present invention is improved. Means.

  Hereinafter, the present invention will be described more specifically with reference to examples.

  Using a blank in which a non-stretched polypropylene film with a thickness of 40 μm is laminated on the surface of a cup base paper having a basis weight of 290 g / m 2 (thickness of about 310 μm), and the corners are quarter-circular quadrangular and radially creased. A drawn paper container having an outer dimension of 165 × 115 mm, a depth of 25 mm, and a width of the flange portion of 7 mm was obtained by drawing with a male mold and a female mold having a mold temperature of 110 ° C.

With respect to the drawn paper container obtained as described above, the ultrasonic seal method is applied to the crease at the corner of the flange portion under the conditions of Ti horn cylinder pressure 0.3 MPa, welding time 0.3 seconds, hold time 0.2 seconds. A welded part having a width of 4 mm was formed to obtain a draw-formed sealed paper container. The position of the welded portion was substantially the center with respect to the width direction of the flange portion, and was a non-welded portion of 2 mm on the outside and 1 mm on the inside.

  A welded portion is formed in the same manner as in Example 1 except that the width of the upper end edge surface of the receiving jig is the same as the width of the flange portion and is in contact with the entire flange portion by ultrasonic sealing. A molded sealed paper container was obtained.

  The draw-formed sealed paper container obtained in Example 1 has no resin protrusion (resin burr) on the inner side or the outer side in the width direction of the flange portion, and lacks hygiene and appearance in addition to sealing performance. It was not. On the other hand, the draw-formed sealed paper container obtained in Example 2 had a resin burr of 0.5 mm on the inner side in the width direction of the flange portion and 1 mm on the outer side. Furthermore, in Example 1, even if the welding time was shortened to 0.2 seconds, sufficient weldability could be exhibited, and the welding time and pressure could be shortened.

It is a perspective view which shows one Embodiment of the draw-formed airtight paper container of this invention. It is explanatory drawing which represented one Embodiment of the blank which comprises the draw-forming sealing paper container of this invention with the plane. It is explanatory drawing showing the example of the drawing of the draw-formed airtight paper container of this invention with the side cross section. It is explanatory drawing which represented the example of the welding process of the draw-formed sealing paper container of this invention with the side cross section. It is explanatory drawing which represented in the plane the example of the welded flange part of the draw-formed sealed paper container of this invention. It is an expanded explanatory view showing an example of the welded flange part of the drawing-formed sealed paper container of the present invention in a side section. The processing state of the wrinkle part of the flange part which comprises the draw-formed airtight paper container of this invention is demonstrated, (a) is an enlarged schematic diagram showing the example before a welding process in the side cross section, (b ) Is an enlarged schematic diagram showing a case after welding processing in a side cross section, and (c) is an enlarged schematic diagram showing a case after pressing in a side cross section. It is explanatory drawing which represented the example of the press work of the flange part which comprises the draw-forming sealed paper container of this invention with the side cross section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Drawing forming sealing paper container 3 ... Blank 10 ... Bottom part 12 ... Side wall part 14 ... Flange part 14a ... Wrinkle part 14a-A ... Wrinkle part 14W crushed with a press machine ... Width 15 ··· Curved portion center position 15a ··· Arc-shaped curved portion 16 ··· Folded crease 18 · · · Welded portion 18W · · · Width of welded portion 20 · · · Sealing cover material 30 · · · Paperboard 32 · · · Thermoplastic Resin layer 50 ··· Ultrasonic horn 60 ··············································································· 100

Claims (5)

  Using a blank in which a thermoplastic resin layer is applied to at least one surface of a sheet of paperboard and radial crease lines are applied to the corners of the baseboard, the bottom is processed by drawing, and the side walls are connected to the bottom. And a flange portion extending in a horizontal direction and extending horizontally to the side wall portion, wherein the crease line is folded to form a wrinkle portion. A draw-formed sealed paper container, wherein the wrinkle portion is welded with a width smaller than the width of the flange portion.   2. The draw-formed sealed paper container according to claim 1, wherein the position welded with a width smaller than the width of the flange portion is substantially at the center in the width direction of the flange portion and at least inside both side edges.   The draw-formed sealed paper container according to claim 1, wherein the welded width is in a range of 10 to 80% of a width of the flange portion.   4. The drawn molded sealed paper container according to claim 1, wherein the thickness of the thermoplastic resin layer is in the range of 5 to 40% of the thickness of the paperboard base paper. 5. The draw-formed sealed paper container according to any one of claims 1 to 4, wherein the entire flange portion is pressed after the wrinkles at the corners of the flange portion are welded.

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