JP2003039576A - Method and apparatus for treating edge of paper container raw paper, paper container raw paper subjected to edge treatment and paper container molded from raw paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain paper container raw paper generating no paper powder or the like, not using an adhesive, unnecessary to heat-seal a tape, unnecessary to be heated, subjected to edge treatment efficiently and capable of enhancing the hermetic sealability of the side seam of a paper container or the heat-sealing of a lid material, and to obtain the paper container. SOLUTION: Paper container raw paper edge treatment device 221 , 222 and 223 equipped with molten resin coating nozzles having resin coating slit parts capable of permitting raw paper to pass are successively arranged on the passing side of both side edges of raw paper 20 and different resins are successively extruded to both side edges of the raw paper and molded to coat both side edges of the raw paper with a multilayered molten synthetic resin. Thereafter, two body part blanks per raw paper width are punched to obtain the body part blanks 20 directly having the molten resin coating layers provided to the side edges positioned inside a container thereof. Since the resins are directly extruded to the edges of the raw paper to be molded, it is unnecessary to cut off the edges of the raw paper and no paper powder or the like is generated to bring about sanitary effect and edge treatment can be performed by many kinds of resins such as low density polyethylene or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating an end surface of a base paper or a blank of a paper container such as a paper cup or a paper box and an apparatus therefor, a raw paper container base paper and a paper container formed by the base paper.

[0002]

2. Description of the Related Art A base paper for a paper container such as a paper cup is a paper in which a resin for moisture prevention is laminated or coated on the inner surface with which the inner solution comes into contact, and the front side is also laminated or coated as necessary. When a cup is manufactured from the paper, for example, the cut end faces are polymerized and adhered to form a body, but the cut face of the paper material faces the inside of the container and contacts the inner solution as it is. It will be.
For this reason, the end face of the base paper or the blank (hereinafter, both are simply referred to as “base paper” unless they are distinguished from each other) is end-face treated so that the cut surface is not directly exposed.
Conventionally, as a method for treating the end face of a container base paper, as shown in FIG. 9 (a), the end face of the base paper 40 is scraped off with a cutter, and then a crease line recess 42 is formed in the center of the scraped face 41, and an adhesive A so-called sky bar treatment method is known in which 43 is applied and the scraped surfaces are bent and pressure-bonded so that they adhere to each other (see, for example, Japanese Patent Publication No. 59-47983). Further, as another method, as shown in FIG. 9B, a tape attaching method is known in which an end face of the base paper 40 is heated and a heat adhesive tape 44 is attached to the end face so as to cover the cut surface. Has been.

[0003]

However, the former method has a drawback that paper dust when the paper is scraped tends to adhere to the surface of the raw paper, and in order to surely bend the paper, the width of the raw paper to be shaved is There is a problem that must be increased. Further, there is a problem in that the viscosity of the adhesive (glue), the amount applied, etc. must be accurately controlled depending on the temperature and humidity. In the latter method, it is necessary to slit a heat-adhesive film into a width of about 10 mm to make a heat-adhesive tape, but the film needs rigidity due to its mechanical suitability, and it is necessary to use a low-density polyethylene single layer. However, it is difficult to use such a film, and the film to be used is limited. In addition, there is a problem that the resin surface of the base paper needs to be heated when the tape is attached, and that portion is oxidized, so that a lid seal failure or the like may occur in the case of a paper container. Further, both of the above-mentioned two conventional methods have a problem that the process is complicated and the production efficiency is poor. On the other hand, in a paper container molded from base paper that has been end-face treated by the conventional end-face treatment method, a step can be formed on the side-seam surface, so that the stepped portion can seal the cup bottom surface and heat the lid material on the top surface. It was a factor that hinders the sealing performance when sealed.

The present invention was devised in view of the above circumstances and is hygienic without generation of paper powder or the like, and does not require the use of an adhesive (glue) or heat sealing. , And there is no need to heat the base paper or substrate in advance,
The lid material can be reliably welded, no film is used, the process is simple and the production efficiency can be improved, and the sealability of the side seam of the paper container and the heat seal of the lid material can be improved. An object of the present invention is to provide an end surface treatment method for a paper container base paper, a manufacturing apparatus therefor, and a paper container base paper and a paper container which can be improved.

[0005]

In order to solve the above problems, the method for treating the end surface of the base paper for a paper container according to the present invention is such that the end surface of the base paper for a paper container is extruded with a molten synthetic resin to cover the end surface of the base paper with the molten resin. It is characterized by that. The synthetic resin may be a single kind of synthetic resin, but if necessary, in order to have more functionality, it is also possible to extrude multiple layers of different synthetic resins and coat them with multiple layers of molten synthetic resin. In that case, it is also possible to extrude multiple layers of molten resin with one extrusion nozzle, and it is also possible to sequentially extrude different resins onto the end face of the base paper with different nozzles and coat them with multiple layers of molten synthetic resin. Is.

The paper container base paper end surface treating apparatus of the present invention for carrying out the above-mentioned paper container base paper end surface processing method has a nozzle hole at the tip of the molten resin extrusion channel, and the base paper is provided at the tip of the nozzle hole. It is characterized in that a molten resin coating nozzle having a resin coating slit portion that can pass therethrough is provided. The slit portion for resin coating includes a molding portion and a widening portion, the molding portion is composed of a portion having a high cross-section height and a low portion, and the low portion is slightly wider than the thickness of the base paper. It is desirable to form.

The paper container base paper of the present invention is a base paper for forming a paper container whose end surface has been treated as described above, and is formed by coating at least one side end surface of a portion to be a seal end surface with a molten synthetic resin. It is characterized by that. And
The paper container of the present invention is formed from the paper container base paper and is characterized in that the side seam step is filled with resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. FIG. 1 schematically shows a method and an apparatus for processing an end surface of a paper container base paper according to an embodiment of the present invention. The end surface treatment method for a paper container base paper according to the present embodiment is shown in FIG. 2 by directly extruding a molten synthetic resin (hereinafter, simply referred to as resin) to the edge portion of the base paper 1 fed from the base paper roll. As shown in the drawing, a resin coating portion 5 is formed on the end face of the base paper 1 so that the end face is completely covered with resin, and end face treatment is performed so that the paper material is not exposed from the edge. As shown in FIG. 2, the resin coating portion 5 is formed on both ends of the edge of the base paper, and the double-sided coating portions 3 and 3 that cover both sides of the base paper, and the tip ends of the double-sided coating portions 3 and 3. It is desirable that the resin reservoir 6 be formed so as to have the resin reservoir 6.

In FIG. 1, reference numeral 10 denotes a main part of a paper container base paper end surface processing apparatus for extruding and molding a molten synthetic resin on the end surface of the base paper, and applying the melt resin to an extrusion die 11 connected to a melt resin extruding cylinder (not shown). The nozzle 12 is provided. The molten resin coating nozzle 12 is composed of a molten resin extrusion flow path 13, a nozzle hole 14 located at the tip thereof, and a resin coating slit portion 15 through which the end face portion of the base paper 1 can pass. Molten resin is continuously extruded on the side edges of the base paper passing therethrough to cover the edges of the base paper. The slit portion 15 for resin coating formed across the tip of the molten resin coating nozzle 12 serves as a molding die for forming a resin coating on the end surface of the base paper, and the shape of the resin coating portion differs depending on its shape. come. 3 to 5 show examples of molten resin coating nozzles having different resin coating slit portions.

[0010] Figure 3 the molten resin coating nozzle 12 ₁ shown is about one third the diameter of the nozzle hole 14 ₁ of the molten resin extrusion passage 13 ₁
Slit 15 for resin coating, which has a diameter of the order
Reference numeral ₁ denotes an expanding portion 16 ₁ whose tip portion expands in a tapered shape so that the base paper can be easily guided into the slit, and the inside thereof covers the end surface of the base paper with the molten resin extruded from the nozzle hole. It is a molding part 17 ₁ that is molded into. The forming part 17 ₁ of this embodiment is formed in a slit having a single cross-sectional shape slightly larger than the thickness of the base paper.

The molten resin coating nozzle 12 ₂ shown in FIG.
The hole diameter of the nozzle hole 14 ₂ is the same as that shown in FIG. 3, but the molding portion 17 _{2 of} the resin coating slit portion 15 ₂ has a wide cross-section portion 18 having a high cross-section height up to about the middle, and the base paper following it. It is formed slightly higher than the thickness, but is formed from a narrow cross section portion 19 which is lower than the high cross section portion. Further, the molten resin coating nozzle 12 ₃ shown in FIG.
Is a narrow cross section in which the nozzle hole 14 ₃ is formed to have the same diameter as the molten resin extruding flow path 13 ₃ and the molding portion 17 _{3 of} the resin coating slit portion 15 ₃ is formed to be slightly narrower and shorter than the base paper thickness. And an enlarged portion 16 _{3 which} is formed to have a large length and is formed at the tip thereof.

As shown in the above embodiment, the molten resin coating nozzle is extruded from the nozzle hole 14 by having a molten resin coating slit portion consisting of an expanded portion and a molding portion at the tip of the nozzle hole. The molten resin flows along both sides of the end surface of the base paper passing through the slit portion, and the molten resin can be applied to both sides and edges of the base paper to cover the end surface of the base paper. The shape of the slit portion for the molten resin coating,
For example, the shape shown in FIGS. 3 to 5 can be adopted, but as shown in FIG. 3, the slit shape of the forming part is straight and the gap between the base paper passing through the position is small. If so, there is a fear that the resin extruded from the nozzle hole may flow to one side of the base paper. Therefore, in order to make the resin flow evenly on both sides, as shown in FIG. It is desirable to have a shape with a large cross-sectional area. In that case, the cross-sectional shape of the molded portion is not necessarily limited to the intermittent change as shown in FIG. 4, and may be a shape in which the cross-sectional area continuously changes in a taper shape or a curved shape.

The molten resin extruded from the molten resin coating nozzle is not limited to a single type of resin, and for example, both sides are made of a resin having excellent paper adhesion and the center layer is made of a resin having excellent barrier properties. It is also possible to simultaneously extrude the resins in a laminated state from one nozzle. As another method, a plurality of molten resin coating nozzles are arranged in series along the passage of the end face of the base paper, and different molten resins are extruded from these molten resin coating nozzles to form different end faces of the base paper. Can be laminated and coated.

FIG. 6 shows an embodiment in which, when the blank 20 for forming the body portion of the paper cup is obtained from the base paper 21, the end surface of the base paper is directly coated with the molten resin for end face treatment. In the present embodiment, a case is taken in which two blanks are taken in the width direction of the base paper, and three sets of paper containers are sequentially provided on the side where both end face portions of the base paper 20 that is rewound from the original roll and supplied are passed. Base paper edge processing device 22 ₁ , 22 ₂ , 22 ₃
Is arranged, for example, low-density polyethylene is applied from the first and third sets of molten resin coating nozzles, an ethylene vinyl alcohol copolymer is supplied from the second set of molten resin coating nozzles,
Alternatively, a resin coating layer composed of three layers is formed on both side edges by applying a mixture of an ethylene vinyl alcohol copolymer with a resin having good adhesion to low density polyethylene. Further, in the present embodiment, in order to increase the speed of the line, a heater 23 for preheating is arranged on the upstream side of the molten resin coating nozzle to heat the edge of the base paper before coating the molten resin to melt the molten resin. It is designed to improve the adhesiveness with. Since the preheating can be welded to the base paper or the resin layer by the heat of the molten resin itself, it is not necessary to heat the base paper to such an extent that it is oxidized, and heating at a surface temperature of about 60 ° C. is sufficient. However, preheating is not always necessary, and the base paper or resin layer can be sufficiently welded by the heat of the molten resin itself without preheating the base paper in the low-speed line. Further, a cooling / compression means 24 for cooling / compressing the molten resin applied to both edges of the base paper is provided on the downstream side of the paper container base paper end surface processing device, and a blank from the base paper is further provided on the downstream side thereof. A punching device (not shown) is arranged.

In the above cup manufacturing line,
The base paper 21 can be obtained as a base paper whose both edges are coated with three layers of molten resin by passing through the resin coating section in which the paper container base paper end surface processing device 22 is arranged. As shown in FIG. 6, the base paper was punched into a fan shape with a press so that one side end surface portion thereof was coated with the molten resin.
One body blank 20 can be obtained at the same time. As shown in FIG. 7, the obtained body blank 20 has a resin coating portion 26 formed on one side end surface portion 25 which is a joining edge.
The side end surface is completely covered with resin.
At the time of forming the body part, by joining so that the side end surface part 25 having the resin coating part is located inside, the cut surface of the base paper is not directly exposed on the inner surface of the cup, and the paper material is exposed to the content liquid. There is no.

FIG. 8 shows a paper cup 30 manufactured from the body blank 20 obtained as described above and a separately molded bottom blank. The paper cup is the same as the one formed by the conventional method except that the side seam portion of the body portion is joined by welding the molten resin coating portion formed on the blank side end surface portion. The paper container obtained in this way is different from the method of bonding the tape by heating the base paper in the case of the conventional tape sticking method, in which the blank joining end surface treatment is different from the base paper with the heat source of the molten resin itself. To weld
Since it is not necessary to heat the base paper to such an extent as to oxidize the base paper, there is no decrease in welding when sealing the lid material, and the lid material can be welded satisfactorily. Further, when a molten resin is directly extruded onto the blank end face and applied to form a cup, a B portion which is an overlapping portion of the side seam portion 31 and the bottom seam portion 32 of the cup is shown in FIG. 8C. As shown in an enlarged scale, since the amount of resin on the joint end surface increases, the step of the side seam of the paper container is filled with the resin 33, which is very effective in preventing water leakage. Further, the top curl portion 3 which is the seal portion of the lid material
Since the side seam step (A portion) that can be formed with No. 4 is also filled with the resin 33 as shown in an enlarged view in FIG. 8B, when the lid member is heat-sealed, the side seam step hinders the sealing performance. No longer occurs and the sealing performance is improved.
Such action and effect cannot be expected in the paper container formed from the base paper treated by the conventional end face treatment method.

[0017]

[Experimental example] Low-density polyethylene 37μ / acid-proof paper 300g
/ m ² / low-density polyethylene 18μ of three-layer base paper using the molten resin coating nozzle 12 ₂ shown in FIG. Was continuously applied. Observing the coating state, it was found that both sides of the end face of the base paper were covered with the resin, and the resin was retained at the leading end i, and the resin coat was well formed in a state close to the shape shown in FIG. It was visible. Further, ethanol was applied to the resin-coated portion to confirm the number of pinholes, but no pinholes were observed on the treated surface. From the above experimental results, it was confirmed that the method and apparatus for processing the end surface of the paper container base paper according to the present invention is effective for the end surface processing of the paper container base paper.

The embodiment of the present invention has been described above.
The present invention is not limited to these embodiments, and various design changes can be made within the scope of the technical idea thereof. For example,
In the above-described embodiment, the edge processing is performed at the stage of the base paper, but the edge processing may be performed at the time of blanking, and whichever has higher production efficiency may be adopted. Therefore, the “base paper” in the claims should be construed to include not only the base paper but also “blank”. The paper container is not limited to a paper cup, and includes various types of paper containers having side seam portions.

[0019]

As described above, according to the end surface treatment method and end surface treatment apparatus for a paper container base paper of the present invention, resin is extruded directly onto the end surface, and therefore paper dust or the like is not generated, which is sanitary.
Further, since the resin is directly extruded and molded on the end face, it is possible to treat the end face with various kinds of resins such as low density polyethylene.
Further, since the end face processing can be performed while continuously feeding the base paper and the processing process is simple, it is possible to increase the speed.

Further, according to the paper container base paper of the present invention and the paper container formed from the base paper, the formation of the resin coating portion on the joint end face portion of the blank is caused to adhere to the base paper by the heat of the molten resin itself, Since it is not necessary to heat the base paper to such an extent as to oxidize the base paper, there is no reduction in welding when the lid material is sealed, and the lid material can be welded satisfactorily. In addition, since the molten resin is applied directly to the blank end face by extrusion molding, when molded into a paper container, the side seam step of the paper container is filled with resin, which is very effective in preventing water leakage and the lid material. The side seam step on the top surface, which is the sealing part, was filled with resin, and when the lid material was heat-sealed, the step did not hinder the sealing performance, and the sealing performance was improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a method and an apparatus for processing an end surface of a paper container base paper according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a side end surface of a base paper that has been end surface-treated.

3A and 3B show an embodiment of a molten resin coating nozzle of a paper container base paper end surface processing device of the present invention, wherein FIG. 3A is a front view and FIG. 3B is a right side view.

FIG. 4 shows another embodiment of the molten resin application nozzle of the paper container base paper end surface processing device of the present invention, (a) is a front view,
(B) is a right side view.

5A and 5B show still another embodiment of the molten resin coating nozzle of the paper container base paper end surface processing device of the present invention, wherein FIG. 5A is a front view and FIG. 5B is a right side view.

FIG. 6 is a schematic diagram showing an end face processing method and apparatus for a paper container base paper according to an embodiment of the present invention in a step of obtaining a body blank of a paper cup from the base paper.

FIG. 7 shows a main part of a body blank of a paper cup, (a)
Is a plan view and (b) is a front sectional view thereof.

8 shows a paper cup manufactured using the body blank shown in FIG. 7, (a) is a perspective view, (b) is an enlarged view of part A, and c) is an enlarged sectional view of part B. .

FIG. 9 shows a conventional end surface treatment method for a paper container base paper,
(A) is a sky bar processing method, (b) is a tape sticking method.

[Explanation of symbols]

1, 21 Base paper 2, 25 Edge 3 Double-sided coating part 5, 26 Resin coating part 6 Resin reservoir 10, 22 _{1 to} 22 ₃ Paper container base paper end face processing device 11 Extrusion die 12 (12 _{1 to} 12 ₃ ) Molten resin coating nozzle 13 _{(131-134 3)} molten resin extrusion passage 14 (14 ₁ to 14 ₃₎ the nozzle hole 15 (15 ₁ to 15 ₃₎ resin-coated slit section 16 (16 ₁ to 16 ₃₎ expanding portion 17 (17 ₁ -17 ₃ ) Molding part 18 Wide cross-section part 19 Narrow cross-section part 20 Body blank 21 Base paper 23 Heater 24 Cooling
Crimping means 30 Paper cup 31 Side seam part 32 Bottom material seam part 33 Resin 34 Top curl part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akio Morita             1-5 Komamon, Gotemba City, Shizuoka Prefecture Tokan Kogyo Co., Ltd.             Company Technology Development Center F-term (reference) 3E060 BC08 DA21 EA03                 3E075 AA02 AA20 BA01 BA31 BB02                       BB22 CA01 DB16 DB35 GA02

Claims (8)

[Claims] 1. A method for treating an end surface of a base paper for a paper container, which comprises extruding a molten synthetic resin on the end surface of the base paper for the paper container and coating the end surface of the base paper with the molten resin. 2. The end surface treatment method for a base paper for a paper container according to claim 1, wherein a multilayer synthetic resin is extrusion-molded to cover the end surface of the base paper with the multilayer molten synthetic resin. 3. The end surface treatment method for a base paper of a paper container according to claim 1, wherein different resins are sequentially extruded and molded on the end surface of the base paper by different nozzles, and the end surface of the base paper is coated with a multilayer molten synthetic resin. 4. A molten resin coating nozzle having a nozzle hole at the tip of the molten resin extruding channel, and a resin coating slit having a resin coating slit through which the base paper can pass, provided at the tip of the nozzle hole. A paper container base paper edge processing device. 5. The paper container end face processing device according to claim 4, wherein the resin coating slit portion comprises a molding portion and an expanding portion. 6. The paper container base paper according to claim 5, wherein the molding portion is composed of a portion having a high sectional height and a portion having a low sectional height, and the low portion is formed to be slightly higher than the thickness of the base paper. Edge processing device. 7. A base paper for forming a paper container, characterized in that at least one side end surface of a portion to be a seal end surface is coated with a molten synthetic resin. 8. A paper container formed by the paper container base paper according to claim 7, wherein side seam steps are filled with resin.