JP2009045882A - Blank of paper vessel and method for producing paper vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a blank wherein a body part of a paper vessel or an edge part of a blank forming the vessel itself is covered by a synthetic resin film and also to provide a paper vessel excellent in a water resistance, an oil resistance and a gas barrier property by using the blank. <P>SOLUTION: In a method for producing a blank forming a body part of a vessel or the vessel itself by punching a blank from a substrate paper, holes are punched previously in the substrate paper at an edge part corresponding to the place to be punched along the edge part, and a thermoplastic resin is laminated on the both surfaces of the substrate paper wherein holes are punched in a thickness of 20 μm or higher, and then a blank is punched from the substrate paper in such a way that the thermoplastic resin film formed in the hole parts constitutes an ear part extending to one edge part of the blank. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  According to the present invention, in the overlapping portion (sticking portion) of the blank forming the body portion or the container body of the paper container, the end portion of the blank that is the inside of the container is covered with a thermoplastic resin coating, and the paper material is exposed. Therefore, the present invention relates to a method for manufacturing a paper container having high water resistance, oil resistance, and gas barrier properties, and a method for manufacturing a blank used in the container.

  A paper container such as a paper cup is usually formed by laminating a synthetic resin on the surface of a paperboard, punching a blank therefrom, and bending or bonding one or more blanks. However, when the blank is punched out in this way, the paper layer is exposed on the cut surface, and the paper portion is exposed at the end of the blank that is inside the container at the bonding portion of the container (the portion that is overlapped and bonded). Will do. When the paper portion is exposed, oil and moisture in the container penetrate from that portion, the odor of the base paper moves into the container, and air and moisture easily enter from the outside of the container. Especially in the case of paper containers used for food, especially in paper cups such as instant noodles that require long-term storage, high water resistance, oil resistance, and gas barrier properties are required. A container in which the paper portion is not exposed is required.

Therefore, in a paper cup used for such a purpose, it is possible to process the end of the blank on the side that becomes the inside of the container at the time of bonding the cup container so that the paper part is not exposed by a method called skive hemming. Has been done. Skive hemming is a process in which a blank laminated with a water-resistant thermoplastic resin such as polyethylene is scraped off in the vicinity of the end of the blank so that the outer surface of the container has a predetermined width from the end and is approximately half as thin. This is a method in which the paper portion is folded back so that the paper portion is not exposed on the end surface of the blank.
In addition, as other methods, a method of applying an oil-resistant / water-resistant tape or applying a hydrophobic solvent to the container inner end portion of the container body bonding portion later is also known. It has been. However, all of these methods have drawbacks such as time-consuming, costly, and defective products are easily generated, and a simpler and more reliable method has been demanded.

  As a method for solving such a problem, Patent Document 1 describes the following method. That is, the vicinity of the position where the body part is bonded to the inside of the cup container from the base paper is punched into a long hole in advance along the edge of the blank to be the bonding part, and the base paper with the long hole is formed. On the other hand, a synthetic resin film is laminated. Then, the blank is punched out from the laminated base paper so that the long hole portion becomes an end portion of the bonding portion of the cup body portion. According to this method, the synthetic resin film extends on the end surface of the blank, which is the inner wall of the cup container body, and the front end of the paper portion can be covered with the coating of this portion, and the paper portion is not exposed on the inner surface of the container. . There are Patent Documents 2, 3, and 4 as improved techniques and applied techniques of Patent Document 1. However, since these techniques are formed on one side of the paper surface, the synthetic resin film formed by stretching to the edge of the blank, and when the paper edge of the blank is insufficiently covered, There was a problem that the thickness of the coating was thin and the paper surface was exposed due to tearing of the coating.

  On the other hand, Patent Document 5 differs from Patent Documents 1 to 4 in that it is a synthetic resin film that is formed by laminating a synthetic resin film after drilling a long hole from both sides of a base paper and stretching it to the end of a blank. The coating is formed from both sides of the paper layer and bonded. However, as in Patent Documents 1 to 4, when the thickness of the coating is thin, the paper surface may be exposed due to tearing of the coating, and in Patent Document 5, it is formed by stretching from both sides of the paper layer. When the container is formed, the synthetic resin film is heat-sealed to the inner surface of the container body, and the appearance of the heat-bonded part may be deteriorated by such a method.

Japanese Patent Laid-Open No. 51-122666 JP 2004-106843 A JP 2005-132419 A JP 2005-272010 A JP-A-57-133046

  The present invention relates to a method for producing a paper container excellent in water resistance, oil resistance, and gas barrier properties by covering the edge of a blank in a bonding portion of a paper container with a synthetic resin film, and a method for producing a blank used for the same. Is to provide. In particular, to solve the problems in the above-mentioned patent documents, more easily and without failure, to manufacture a paper container whose bonded portion is reliably covered with a synthetic resin coating, and the paper container It is providing the manufacturing method of the blank used for.

In order to solve the above problems, the present invention first proposes a method for manufacturing a blank for a paper container described below. That is, by overlapping one end of the blank punched out from the base paper and the other end, a method for manufacturing a paper container blank that forms a container body or a container body,
a: a step of previously drilling a hole along the end of the base paper corresponding to the one end of the blank to be punched;
b: a step of laminating a thermoplastic resin on both sides of a base paper having holes formed so that each surface has a thickness of 20 μm or more, and forming the thermoplastic resin film in the hole portion;
c: a step of punching a blank from the base paper so that the thermoplastic resin film formed in the hole portion becomes an ear extending to the one end,
It is a manufacturing method of the blank of a paper container including each process of said a-c.

  According to the above manufacturing method, at the time of forming the body portion or the main body of the paper container, at least one end portion of the blank end portion that becomes the portion to be overlapped and adhered (the inner side of the container by overlapping at the time of container forming) The edge of the blank) is stretched from both front and back sides of the paper material (base paper) to form ears so as to wrap the edges of the paper, and has a thickness of 20 μm or more on one side. Therefore, the film has sufficient coverage, and a film having sufficient strength can be formed even when the thermoplastic resin film is formed in the holes formed in the base paper. In addition, as a method of laminating the thermoplastic resin on both surfaces of the base paper in the step b, an extrusion method is particularly excellent in that the ear portion can be formed so as to wrap the end portion of the paper material.

  In the present invention, the following step d may be added after the steps a to c. That is, d: a step of folding the edge portion extending to one end portion of the blank blanked out toward the outside of the container when the container body portion or the container body is formed. It is a manufacturing method.

  By adding the step d above, the thermoplastic resin ears are sandwiched between both blanks when the flange ends are overlapped and stuck together, so that the joining ends of the thermoplastic resins in the ears are The edge of the paper part is surely covered with the thermoplastic resin without being exposed in the container. In addition, since the sticking part (overlapping part) of the blank end when forming the container body part or the container body has an increased thickness due to folding of the ear part, the heat sealing at the time of container molding in the next process In addition, this portion is melted and the end portion can be sufficiently covered. Moreover, the finish of the container inner surface of the overlapping portion is also beautiful.

Moreover, this invention can also perform the process with respect to one edge part of the blank in said each invention with the both ends (one edge part and the other edge part) of the blank which piles up and adheres. The manufacturing method of the blank in that case is
A: A step of previously drilling holes along both ends of the blank corresponding to the one end and the other end of the blank to be punched,
B: a step of laminating a thermoplastic resin on both surfaces of a base paper having holes formed so that each surface has a thickness of 20 μm or more, and forming the thermoplastic resin film in the hole portion;
C: a step of punching a blank from the base paper so that the thermoplastic resin film formed in the hole portion becomes an ear extending from the one end and the other end,
It is a manufacturing method of the blank of a paper container including each process of said AC.

  If the manufacturing steps A to C are used, both ends (one end and the other end) of the blanks that are overlapped and pasted together are formed with thermoplastic resin ears so as to cover the edge of the paper part. Water resistance, oil resistance, and gas barrier properties from the outside of the container are also improved. In step B, as in the case of step b, as a method for laminating the thermoplastic resin on both surfaces of the base paper, a method by extrusion is preferable.

Moreover, this invention may add the following D process further after the process of AC which forms the ear | edge part of a thermoplastic resin in the both ends of the said blank. That is,
D: Fold the ears extending to one end of the blank punched out toward the outside of the container when forming the container body or the container body, and extend to the other end of the blank Folding the ear part toward the inside of the container when forming the container body or the container body,
A method for producing a blank for a paper container, further comprising:

  Thus, when both ends of the blank (one end and the other end) are formed with thermoplastic resin ears that cover the paper edge, the blanks are overlapped when forming the container. Unlike the end (one end) of the blank that is inside the container, the end of the blank (the other end) located on the outside of the container is the opposite side of the ear, that is, the container. It is better to fold the ears inward. This not only cleans the outer appearance of the container, but the ears of the thermoplastic resin film are sandwiched between the inner and outer blanks, and the amount of thermoplastic resin increases and melts in this part, so the edge of the paper part This is because the edge can be sufficiently covered.

  Furthermore, this invention is a manufacturing method of the paper container using the blank manufactured by said each manufacturing method, Comprising: One edge part of the said blank is inside a container, Said one edge part And a process for producing a paper container, including a step of heat-sealing the other end. The paper container manufactured in this way is made of paper with excellent water resistance, oil resistance, and gas barrier properties, with the edge of the paper not being exposed in the blank overlapping part (sticking part) on the inner surface of the container. It becomes a container.

  Moreover, in each manufacturing method of said blank, when it is the state which is not folding the end surface of a blank (when not taking process d or D), the width | variety of the ear | edge part extended to the edge part of a blank shall be 1-3 mm, Instead of folding the ears, one end of the blank may be the inside of the container, and the one end and the other end may be overlapped and heat sealed. Thus, when the width of the ear portion (length extending from the paper edge) is as short as 1 to 3 mm, the ear portion is contracted and melted in the heating process at the time of molding even if the ear portion is not folded. The finished part is beautiful.

  According to the blank manufacturing method of the present invention, at the time of forming the container body or the container body of the paper container, at least one end of the end of the blank to be overlapped and adhered (the container when overlapped) Since the edge of the paper part of the blank inside) can be reliably and sufficiently covered with a thermoplastic resin film, a paper container having excellent water resistance, oil resistance, and gas barrier properties is manufactured. Can do. In addition, because the paper cut is not exposed, when used as a food container, the paper portion does not touch the food directly, and there is no shift to paper such as paper odor components. You can do better. Furthermore, compared with the conventional skive hemming process, it is not necessary to scrape the blank edge to half the thickness, and the process is not troublesome and cost merit is high.

  Embodiments of the present invention will be described below with reference to the drawings, taking an inverted truncated cone-shaped cup-shaped container as an example. The drawing is a schematic diagram. FIG. 1 shows a state in which a hole is punched out in the vicinity of a paper base paper 1 along a portion corresponding to one end of a blank. The hole 2 punched out in a strip shape is a part of one end of the blank that becomes the body part of the cup container, and is a part that is overlapped and attached to the end (the other end) opposite to the blank at the time of cup molding. This is the end on the side that becomes the inside of the container when overlapping. FIG. 1 shows a punched (planned) line 3 when a blank is punched with a broken line.

  The base paper 1 may be a paper material having sufficient strength as a cup container, and may be one in which a synthetic resin is laminated on one side or both sides, or may be printed in advance. If the width of the strip of the strip-shaped punching portion corresponding to one end of the blank is narrow, the paper edge of the blank may not be sufficiently covered by the thermoplastic resin film formed in the subsequent steps. Therefore, it should be 2 mm or more, preferably 5 mm or more. Further, if the width is too narrow, extreme accuracy is required for positioning when blanking. If the width is set to 15 mm or more, there is a risk that the resin film may be broken when the thermoplastic resin is laminated, so the width of about 5 to 15 mm is the best.

  Next, as shown in FIG. 2, a thermoplastic resin is laminated on both the front and back surfaces of the base paper 1 having a strip-shaped hole. In FIG. 2, the “surface resin layer 5” is the side that becomes the outside of the container when molded into a container, and the “back surface resin layer 4” is the side that becomes the inside of the container when molded into the container. The lamination method is best by the method of extrusion (melt extrusion), but various lamination methods such as dry lamination can be adopted. The method using the extrusion method is preferable because the thermoplastic resin laminated from both sides of the paper layer can be bonded to each other so as to cover the edge of the paper portion in the strip-shaped hole portion formed in the base paper. Yes, it is desirable to adopt a lamination method by extrusion on both sides.

  The thermoplastic resin may be laminated on either the back side or the front side first, but both are laminated so as to have a thickness of 20 μm or more. If the thickness is 20 μm or less, the thermoplastic resin film formed in the strip-shaped hole portion may not be successfully formed, or the laminated thermoplastic resin film may be easily broken at the edge of the paper portion. The thermoplastic resin to be laminated is a synthetic resin having thermoplasticity, and polyethylene, polypropylene, polyamide, ethylene-vinyl alcohol copolymer, polyester, etc. can be used. good. However, it is most preferable to use a polyethylene resin as the thermoplastic resin because it can be laminated by extrusion and has excellent processability to paper.

  As shown in FIG. 2, when the thermoplastic resin layers 4 and 5 are laminated on the front and back surfaces of the base paper, only the thermoplastic resin layer is present in the perforated strip-shaped hole without the paper layer. Laminated from the front and back surfaces of the base paper, the edge of the paper is sealed with a thermoplastic resin. The thickness of the thermoplastic resin formed in the strip-shaped hole thus formed is 40 μm or more, preferably 50 μm or more and 150 μm or less in total from both the front side and the back side. In this state, printing may be performed on the surface side by gravure printing or the like.

  Next, as shown in FIG. 3, a blank serving as a container body is punched with a punching line 3. When one end of the blank is punched so as to match the above-mentioned strip-shaped punching position, the paper edge of one end is sandwiched between the laminated thermoplastic resin films as shown in FIG. An ear 6 made of a thermoplastic resin is formed at one end of the blank so as to be covered and further extended from the edge of the paper part.

  After creating a blank in this way, the container body is then formed using this blank. That is, one end of the blank punched out as described above is positioned inside the container when the container body is molded, and is overlapped with the other end of the blank and heat sealed. Thereby, it becomes a container body part shape of an inverted truncated cone shape. At this time, since the edge of the blank inside the container is in a state where the edge of the paper part is covered with the ear part formed of the thermoplastic resin, the paper material is not exposed on the inner surface of the container. Water resistance, oil resistance, and gas barrier properties can be imparted to the surface.

  In addition, as a heat sealing method at this time, in addition to a method of heat-pressing the overlapped portions by a heat sealer, the end portions of the blank are softened or melted by hot air, and the end portions are overlapped and bonded together. Etc. are possible. When melted and pasted using hot air, the width of the ears extending to the blank end is preferably about 1 to 3 mm. The finish around the landing is beautiful.

  Further, after punching out the blank as described above, the ear 6 of the thermoplastic resin formed at one end of the blank can be folded. By folding the ear part of the thermoplastic resin, the appearance of the sticking part is good and the coverage of the edge of the paper part is further enhanced. In this way, when the ear 6 formed at one end of the blank is folded, the ear 6 is folded back toward the outer side (surface side) when molded into a container as shown in FIG. Is good. This is an advantage of preventing the exposure of the paper material that occurs when the bonding is not sufficient by preventing the bonding surface between the thermoplastic resins of the ears from being exposed on the inner surface of the container. This is because by increasing the amount of the plastic resin, there is an advantage that the adhesiveness is improved and the coating of the edge of the paper portion with the thermoplastic resin is more surely ensured. In the case of folding, it is preferable to fold the ears 180 degrees at a position within about 3 mm from the edge of the paper part, preferably as close as possible to the edge of the paper part, and heat-seal the folded ear part once.

FIG. 6 shows a place in which a blank having one end folded as described above is formed into a cylindrical shape, and one end and the other end of the blank are overlapped to form the body of the cup container. After overlapping the end portions of the blank in this way, the portion is bonded by thermocompression bonding, or the bonding portion around the end portion including the ear portion is softened or melted with hot air. The ends are overlapped and pasted.
After forming the body of the cup-shaped container as described above, a container bottom blank is fitted by a conventional method, and if necessary, the periphery of the container opening is curled to the outside of the container to form a flange part, Use a paper cup-shaped container.

  In FIGS. 1-6, although the method of forming the ear | edge part of a thermoplastic resin in one edge part of a blank and shape | molding a container using this blank, both of the blanks which overlap and stick are attached. The end portions (one end portion and the other end portion) can also form an ear portion of thermoplastic resin. As shown in FIG. 7, as shown in FIG. 7, the end portions of the blanks to be punched and the end portions corresponding to both the one end portion and the other end portion to be overlapped and stuck to each other are attached. The strip-shaped holes 12 and 22 are formed in the base paper along the line. Thereafter, as in FIGS. 2 to 4, the thermoplastic resin is laminated on both sides of the base paper, and the thermoplastic resin film formed in the strip-shaped holes extends to one end and the other end of the blank, respectively. What is necessary is just to punch a blank so that it may become the ear | edge part to install.

  After punching the blank in this way, the container body may be formed in the same procedure, but when folding the ear part, the blank located outside the container when overlapping and sticking is inside the container It is preferable to fold the ears in the direction opposite to the blank located at the position. That is, as shown in FIG. 8, the ear 16 of the end (one end) of the blank that is the inside of the container is folded toward the outside of the container, while the end of the blank that is the outside of the container (the other end). Part) is preferably folded back toward the inside of the container. By folding in this way, both the inner surface of the container and the outer surface of the container have a good appearance of the blank sticking portion, and the thermoplastic resin in the ear portion is sandwiched between the blanks, so that the amount of the thermoplastic resin is large. Therefore, both the bonding property between the blanks and the covering property of the edge of the paper part are improved. In addition, by forming the ear | edge part in both the edge parts of a blank, the water resistance of a container, oil resistance, and gas barrier property can be improved with respect to the environment outside a container.

  As mentioned above, although embodiment of this invention was demonstrated to the example of the cup-shaped container, both the manufacturing method of the blank of this invention and the manufacturing method of paper-made containers can be utilized also for paper-made containers other than cup shape. For example, the present invention can be applied to a box-shaped paper container or a cylindrical paper container used for beverage packs. In any case, not only in the container body, but at both ends of the blank to be overlapped and pasted, at least the end (one end) of the blank that is inside the container when overlapping The ears of the thermoplastic resin are formed in the same manner as in the cup-shaped container.

  Moreover, the container manufactured by the manufacturing method of the blank of this invention and the manufacturing method of the paper container using this blank is excellent in water resistance, oil resistance, and gas barrier property, and the odor component of paper transfers to the container contents. Therefore, it can be suitably used as a food packaging container, in particular, a container for foods containing moisture and fats and oils such as beverages, instant noodles and instant soups. Below, the manufacture example of paper cups is described.

[Example]
An LDPE (melting point of 106 ° C.) is formed in a cup base paper having a basis weight of 320 g / m ² , with a 5 mm wide and 13 cm long elongated hole, and a thickness of 70 μm on one side of the cup base paper (the outer surface of the container). Low density polyethylene) was laminated by extrusion, and MDPE (medium density polyethylene) having a melting point of 133 ° C. was laminated on the other side (side to be inside the container) by extrusion so that the thickness became 40 μm. As a result, a PE (polyethylene) film having no paper layer was formed in the elongated hole portion.

  Next, after gravure printing was performed on the surface of LDPE (surface on the outside of the container), a fan-shaped blank having a vertical width of 12 cm was punched so that the elongated hole portion was located at the end of the bonded portion of the blank. The width of the ear portion of the thermoplastic resin formed by punching and extending to the end portion of the blank was about 4 mm from the edge of the paper portion.

  In this way, the ear part formed on one end of the blank is turned to 180 ° at the base part of the ear part (as close as possible to the edge of the paper part) toward the LDPE side (surface that becomes the outer side of the container), and thermocompression-bonded. Glued. In the cup molding machine, the blanks with the ears folded in this way are melted with hot air so that the blank ends (one end) on the side where the ears are formed are located inside the container, They were laminated and pasted, and then molded into a cup container by bottom molding and top curl molding. The shape of the cup is an inverted frustoconical shape in which the width of the overlapping portion (sticking portion) of the blank end is about 7 mm, the opening diameter is about 9 cm, the bottom diameter is about 7 cm, and the height is about 10.5 cm.

  About 200 g of powdered soup with a high fat content was placed in the paper cup molded in this manner, and this was left in an environment of 60 ° C., and the soaking of the soup after 24 hours was visually confirmed. The end of the blank was not processed as described above (the cup container was created by punching the blank without making a hole in the base paper, and the edge of the paper was exposed at the end of the blank). Although oozing of fats and oils was confirmed, no oozing of fats and oils was observed in the container of this example.

It is a plane whole view at the time of punching out the edge part vicinity of one end of a blank from base paper in strip shape. FIG. 3 is an enlarged cross-sectional view (schematic diagram) of the periphery of a hole when a strip-shaped hole is formed in the base paper and a thermoplastic resin is laminated on both the front and back surfaces of the base paper. It is a plane whole view at the time of punching a blank from the base paper which laminated | stacked the thermoplastic resin. It is a cross-sectional enlarged view (schematic diagram) in the vicinity of one end of the blank blanked. It is a cross-sectional enlarged view (schematic diagram) when one end of a blank is folded. It is a cross-sectional enlarged view (schematic diagram) near the overlapping portion when one end and the other end of the blank are overlapped, and the downward direction of the drawing is the container outer side direction. It is the plane whole view of the base paper at the time of punching out the vicinity of one edge part and the other edge part of a blank from a base paper in strip shape, respectively. It is a cross-sectional enlarged view (schematic diagram) near the overlapping portion when one end and the other end of the blank are overlapped, and the downward direction of the drawing is the container outer side direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base paper 2 Hole 3 Blank punching line 4 Back surface resin layer 5 Front surface resin layer 6 Ear part

Claims (7)

A paper container blank manufacturing method for forming a container body or a container body by superimposing one end and the other end of a blank punched from a base paper,
a: a step of previously drilling a hole along the end of the base paper corresponding to the one end of the blank to be punched;
b: a step of laminating a thermoplastic resin on both sides of a base paper having holes formed so that each surface has a thickness of 20 μm or more, and forming the thermoplastic resin film in the hole portion;
c: a step of punching a blank from the base paper so that the thermoplastic resin film formed in the hole portion becomes an ear extending to the one end,
The manufacturing method of the blank of the paper container containing each process of said a-c. After step c,
d: a step of folding an ear extending to one end of the blank blanked out toward the outside of the container when the container body or the container body is formed;
The manufacturing method of the blank of the paper container of Claim 1 which further contains these. A paper container blank manufacturing method for forming a container body or a container body by superimposing one end and the other end of a blank punched from a base paper,
A: A step of previously drilling holes along both ends of the blank corresponding to the one end and the other end of the blank to be punched,
B: a step of laminating a thermoplastic resin on both surfaces of a base paper having holes formed so that each surface has a thickness of 20 μm or more, and forming the thermoplastic resin film in the hole portion;
C: a step of punching a blank from the base paper so that the thermoplastic resin film formed in the hole portion becomes an ear extending from the one end and the other end,
The manufacturing method of the blank of the paper container containing each process of said AC. After step C,
D: An ear extending to one end of the blank that has been punched is folded toward the outside of the container when the container body or the container body is formed, and the ear extends to the other end of the blank. A step of folding toward the inside of the container when forming the part on the container body or the container body,
The manufacturing method of the blank of the paper container of Claim 3 which further contains these. The method for producing a blank for a paper container according to any one of claims 1 to 4, wherein the method of laminating a thermoplastic resin on both sides of the base paper having the holes is an extrusion method. A step of heat-sealing the blank manufactured by the manufacturing method according to any one of claims 1 to 5 with one end of the blank as the inside of the container and overlapping one end and the other end. A method for manufacturing a paper container. The blank manufactured by the manufacturing method according to claim 1 or 3, wherein the width of the ear extending to the end of the blank is 1 to 3 mm, and the one end of the blank is not folded. A process for producing a paper container, comprising a step of superposing one end and the other end on the inside of the container and heat-sealing.

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