JP2013256312A - Laminate and paper container using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate and a paper container using the same, having flexibility in the laminate, having good end surface extension film folding for protecting an end surface of a barrel member and moldability in bottom formation, and having a simple layer structure capable of preparing a paper container without leaking liquid during retort sterilization, in the retort paper container.SOLUTION: In a laminate, in which a barrel member is formed in a tubular shape by overlapping one side end edge of the laminate on the other side end edge and in which a flange part is formed by catching its upper end edge by one circumference or more, the laminate comprises thermoplastic resin layers on both surfaces of a paper base material. The thermoplastic resin layer has a multilayer structure including a polyethylene resin layer. The polyethylene resin layer comprises polyethylene resin having a melting point of 122°C or more, and is formed by an extrusion method.

Description

  The present invention relates to a laminate and a paper container using the same, and more particularly to a laminate used for a retort paper cup and a cup-shaped paper container using the same.

  A cup-shaped paper container that is filled with beverages such as juice and the upper opening is sealed with a lid material. A laminated material that uses paper as a base material and is provided with a thermoplastic resin layer such as polyethylene on both sides is specified. The cup-shaped paper container which shape | molded the blank made into the shape by providing the junction part in the trunk | drum was common.

  In addition, when barrier properties against oxygen, water vapor, etc. are required, as a laminated material of the body portion, for example, from the front side, polyethylene (PE) / paper substrate / polyethylene (PE) / aluminum foil / polyethylene terephthalate (PET) Laminate material of layer structure such as film / polyethylene (PE) or layer structure such as polyethylene film (PE) / paper substrate / polyethylene (PE) / plastic film having metal oxide deposited layer / polyethylene (PE) Used to form a cup.

  And in order to ensure the barrier property of the joint part of the cup-shaped paper container, for example, the inside of the joint part of the body member constituting the body part of the cup-shaped paper container is a predetermined length from the tip, and the thickness of the laminated material Are removed (skived), and the remaining half of the shavings are folded back (hemming) so that the deleted surface is on the inside, thereby protecting the end face of the paper substrate from being exposed.

However, in order to perform skive hemming on the end face of the paper substrate, the side edge of the blank is subjected to skive hemming using a special machine before forming a blank body blank into a cup-shaped paper container. There is a need to. For this reason, complicated processing steps have to be performed, and paper dust is generated by removing the paper, and there has been a demand for improvement of surrounding contamination.
Further, since it is necessary to align the skive end faces in a straight line, it is difficult to perform cup molding simultaneously with skive hemming with a cup molding machine.

Therefore, as a method of producing a cup-shaped paper container with excellent barrier properties without performing skive hemming, a cup-shaped paper container is manufactured using a blank in which the end surface of the paper base material constituting the body member is covered with a film. A method has been proposed (see, for example, Patent Document 1).
Further, a laminated sheet having a paper base material having at least an inner surface provided with a thermoplastic resin layer as a base material is punched into a predetermined shape, and a resin portion extending outwardly on one side edge is formed along the end face of the base material. Then, the side-coated edge of the blank coated with the resin part of the blank is overlapped and adhered to the inside of the other side edge to form a body bonded part. Has been proposed (see Patent Document 2).

However, in the cup-shaped paper container having a barrier property that protects the end surface of the paper base material, the inner edge of the body portion bonding portion is produced by extending the thermoplastic resin layer over the entire paper base material. ing. Thus, the film of the thermoplastic resin layer extending from the paper base material is irregularly formed during cup molding, and the original purpose of sufficiently covering the end surface of the paper base material can be sufficiently fulfilled. There was nothing.
Moreover, the finish as a cup-shaped container was bad and there existed problems, such as a malfunction produced in an external appearance.

Further, the cup-shaped paper container is formed with a flange portion by winding the upper end edge of the body member outward one or more times in the opening. Thus, by providing a flange part in an opening part, even when a force is added from the outside, a deformation | transformation of a paper container can be suppressed.
If the strength of the flange portion is sufficient, a lid material can be stacked on the upper surface of the flange portion and sealed.
Moreover, in order to make it easy to seal a lid | cover material, a flange part is pressurized from an up-down direction and it is made into a flat state. As the flattening means, a heating and pressurizing method or an ultrasonic method is used.

  In the cup-shaped container in which the upper end edge of the body member is wound around the opening and the flange portion is formed, a step due to the thickness of the base paper is generated at the flange portion. For this reason, when a lid is placed on the upper surface of the flange portion and heat-sealed as it is, there is a case where the sealing cannot be reliably performed due to the step. In particular, when the flange portion is flattened, the influence of the thickness of the base material is large.

  In order to reliably perform the sealing with the lid member, a filling member made of another resin or the like for filling the step on the upper surface of the flange portion is provided, and a method for eliminating the step or a sealing seal at the position of the step portion is used. However, an increase in processes and materials was inevitable.

  Therefore, in Patent Document 3, a cup-shaped container in which a trunk member is wound into an opening and a flange is formed, particularly a cup-shaped container in which a flat flange is formed, and sealing of a lid is easy, And the method of providing the cup-shaped container which has the function which was excellent in the barrier property with the cup-shaped container excellent in the sealing performance is proposed.

  Here, a container having excellent barrier properties is formed using a body member in which a resin part film made of an extended thermoplastic resin layer protrudes from a side edge located inside the overlapping part. At the time, without affecting the coating of the end face of the paper substrate, and finished as a paper cup, paper containers such as a paper cup having a beautiful appearance and the paper cup or paper container from a continuous paper substrate, A paper container and a paper cup manufacturing method for directly making a paper cup or paper container are disclosed.

In the paper container proposed here, one side edge of a blank composed of a laminated sheet based on paper having at least an inner surface provided with a thermoplastic resin layer is overlapped with the other side edge. In a cup-shaped paper container in which the body part pasting part and the upper end edge are wound around one or more rounds, and a cylindrical body member in which a flange part is formed, and a bottom member integrated in the lower part of the body member,
The side edge located inside the overlapping part of the blank has a resin part extending from the side edge of the base material, and a notch is provided in each upper part of both side edges. It is a cup-shaped paper container.

  The structure of the paper container that can withstand the heat during retort sterilization of the paper container of the above configuration, especially a cup that has been drilled in the paper and pasted the film with an extruder to protect the end face of the origami and water resistance The layer structure of the retort cup laminate to be produced is, for example, currently (CPP) / extruded PP from the viewpoint of preventing foaming of the thermoplastic resin layer in the production process and ensuring adhesion, and heat resistance during retort sterilization. / (CPP // PET // paper // PET // CPP) / extruded PP / (CPP // barrier film // CPP) (see FIG. 2B).

With such a complicated structure, the laminate is hard (rigid), and the end face extension film folding for protecting the end face of the barrel member, the formability such as bottom formation is poor, and a liquid leaking cup can be formed. There is a problem that defects occur.
In order to solve this problem, it has been desired to simplify the layer structure of the laminate.

Japanese Patent Publication No.58-43264 JP 2005-272010 A JP 2008-222244 A

  In retort paper containers, the laminate is flexible, has excellent formability such as end face extension film folding and bottom formation to protect the end face of the body member, and can create a paper container that does not leak even during retort sterilization To provide a laminate having a simple layer structure and a paper container using the laminate.

  A laminated body according to claim 1 of the present invention is a laminated body that includes a paper base and is used for a body member of a paper container, and the paper container is integrated with the tubular body member and a lower portion of the body member. The body member is configured in a cylindrical shape by superimposing one side edge of the laminate on the other side edge, and an upper edge thereof. Is formed by providing a thermoplastic resin layer on both sides of the paper base material, and the thermoplastic resin layer includes a polyethylene resin layer. The laminate has a multilayer structure, and the polyethylene resin layer is made of a polyethylene resin having a melting point of 122 ° C. or more, and is formed by an extrusion method.

  As a thermoplastic resin layer to be applied to both sides of the paper substrate, by using a polyethylene resin by an extrusion method having a melting point of 122 ° C. or more, it does not completely melt at the temperature during retort sterilization, and the paper substrate and the adjacent layer Maintaining the adhesive state and easily preventing foaming in the container forming process, which is a problem when using polypropylene resin, can be easily obtained in a process with less simple layer structure (see FIG. 2 (A)). It is done.

  The laminate according to claim 2 of the present invention is the laminate according to claim 1, wherein the polyethylene resin layer does not contain a linear low-density polyethylene resin having a melting point of less than 122 ° C.

In order to improve the extrusion moldability, the polyethylene resin used for extrusion film formation is often blended with a linear low density polyethylene resin having a lower melting point than usual.
As described above, when a resin containing a low melting point polyethylene resin component is used, it is considered that due to the low melt viscosity, separation or delamination occurs due to outflow or foaming at the time of molding of the container or retort sterilization.
In the laminate of the present invention, the polyethylene resin used for the thermoplastic resin layer is made of a polyethylene (EXPE) resin layer that does not contain a linear low density polyethylene resin having a melting point lower than 122 ° C. Delamination can be avoided.

  The laminate according to claim 3 of the present invention is the laminate according to claim 1 or 2, wherein the polyethylene resin is a polyethylene resin having no plurality of melting points.

  Since the polyethylene resin used for the thermoplastic resin layer is a polyethylene resin that does not contain a plurality of melting points, the resin layer is the same as that made of a polyethylene resin having a broad molecular weight distribution that does not contain a resin component other than the polyethylene resin. It is presumed that it exhibits a good heat melting behavior, and due to its low melt viscosity, it is possible to effectively prevent the problem of causing separation and delamination by causing outflow and foaming during molding of the container and retort sterilization.

The laminate according to claim 4 of the present invention is the laminate according to any one of claims 1 to 3, wherein the density of the polyethylene resin is 0.928 or more.
By making the density of the polyethylene resin used for the thermoplastic resin layer the same as that of a normal low density polyethylene resin or a medium density polyethylene resin, the workability and physical properties other than the above shall be the same as those of a normal polyethylene resin. I can do it.

In the laminate according to claim 5 of the present invention, the thermoplastic resin layer having a multilayer structure is formed by laminating another multilayer film on the polyethylene resin layer, and the multilayer film is previously unstretched polypropylene. 5. The multilayer film in which the film and the polyethylene terephthalate film are bonded together, or the multilayer film in which the barrier film, the unstretched polypropylene film, and the extruded polyethylene layer are bonded together. Or a laminate according to item 1.
Since the polyethylene resin layer is preliminarily pasted to the CPP / PET film or barrier film / CPP film by extrusion method, it is less rigid than the polyethylene film made by extrusion method or inflation method, and mixing of low melting point components This is more preferable.

The laminated body according to any one of claims 1 to 5, wherein the laminated body according to claim 6 of the present invention has a polyethylene terephthalate film, a nylon film, or a barrier film laminated in the layer structure. Is the body.
Since the PET film, the Ny film or the barrier film is laminated in the layer structure, the barrier property can be secured, and at the same time, the effect of preventing damage during molding or transportation can be expected.
Further, since the PET film, the Ny film, or the barrier film is laminated in the layer structure, even if the polyethylene resin is melted at the time of retort sterilization, it does not melt into the contents or the retort kettle.

The laminate according to claim 7 of the present invention is characterized in that the barrier film is a film obtained by depositing an inorganic oxide or a metal on a base film, and the base film is a polyethylene terephthalate film or a nylon film. Item 7. The laminate according to Item 6.
In order to ensure the above effect, the barrier film is preferably an inorganic oxide vapor deposition film or a metal vapor deposition film based on a PET film or Ny film.

  The paper container which concerns on Claim 8 of this invention is a paper container for retorts using the laminated body of any one of Claim 1 to 7.

The paper container of the present invention realizes a simpler manufacturing process than when a conventional polypropylene resin is used by laminating a special polyethylene resin produced by, for example, a low-pressure slurry method on both sides of a paper substrate.
In the conventional method using an extruded polypropylene resin that can withstand the processing temperature during retort sterilization, it is difficult to directly laminate with a paper base material. For example, it is necessary to interpose a film in which a CPP film is bonded to a PET film, The configuration is complicated, and there is also a problem in workability.
For example, in the case of a configuration in which the resin portion extended to the body portion joint portion of the paper base material of the thermoplastic resin is folded back to the outer surface side of the base material, the case of a thermoplastic resin layer further including a gas barrier layer Since there are many constituent layers and the thickness and rigidity are large, the bending process is difficult.

  According to the present invention, the lamination of the CPP film and the PET film in the above portion can be omitted and the amount of lamination can be reduced as compared with the conventional structure, so the rigidity of the laminated body forming the paper container is small and the workability is improved. A laminate can be obtained.

In addition, since a special extrusion polyethylene is used in place of the conventional polyethylene as the thermoplastic resin layer that is laminated directly on the paper substrate by the extrusion method, there is little outflow due to heat during cup processing, and resin during cup processing. There are no problems such as the absence of layers and weak adhesion, and stable processing is possible.
This effect can be further improved by using a resin having a wide molecular weight distribution as a special polyethylene resin for extrusion, since it can have good extrudability such as small neck-in.

Explanatory drawing which shows the manufacturing process of a paper cup. The cross-sectional schematic of the laminated body which comprises a paper cup. (A) is the laminated body of this invention, (B) is an example of the conventional laminated body. The cross-sectional schematic of a paper cup trunk | drum member junction part. The other cross-sectional schematic of the paper cup trunk | drum member junction part. The 1st punching process which provides the long window of the trunk | drum member blank used for manufacture of a paper cup is shown. (A) is plane explanatory drawing, (b) is the A-A 'sectional view explanatory drawing of (a). The thermoplastic resin bonding process of the trunk | drum member blank used for manufacture of a paper cup is shown. (A) is plane explanatory drawing, (b) is the A-A 'sectional view explanatory drawing of (a). The 2nd punching process which punches the trunk | drum member blank which has a resin part used for manufacture of a paper cup in a defined shape is shown. (A) is plane explanatory drawing, (b) is the A-A 'sectional view explanatory drawing of (a). It is explanatory drawing which shows an example of the temporary adhesion | attachment mechanism which bends and temporarily adheres the resin part to the outer surface side of a paper base material. It is explanatory drawing which shows the process of bending and temporarily adhering a resin part to the outer surface side of a paper base material.

A case of a cup-shaped paper container as an example of an embodiment of the present invention will be described below with reference to the drawings as necessary.
The paper container according to the present embodiment has a body portion formed by stacking one side edge on the other side edge of a blank composed of a paper-based laminate having a thermoplastic resin layer provided on both sides. A cup-shaped paper container in which a laminating part and a cylindrical body member in which an upper end edge is wound one or more times to form a flange part, and a bottom member integrated with the lower part of the body member, The side edge located inside the mating portion is a cup-shaped paper container having a resin portion extending from the side edge of the base material and having a notch at each upper portion of both side edges.

By setting the thermoplastic resin layer provided on the inner surface to include a gas barrier layer, a cup-shaped paper container having excellent contents preservability can be obtained.
Moreover, the amount of coating resin necessary for preventing water from entering from the end of the paper base material of the body part pasting portion by making the resin part folded back to the outer surface side or the inner surface side of the base material. Further, in the case of a thermoplastic resin layer including a gas barrier layer, a cup-shaped paper container in which the end surface of the gas barrier layer is not exposed is obtained.

Further, by providing the resin part over the entire length of the side edge, it is possible to obtain a cup-shaped paper container excellent in sealing performance of the body part bonding part other than the flange part.
Moreover, the said resin part is provided in the location containing the said notch part, and the cup-shaped paper container in which the sealing performance of the flange part was further excellent is obtained.

As shown in FIGS. 5, 6, and 7, the paper container of the present invention is blanked by punching a long window having a predetermined shape at a predetermined position of a side edge portion serving as a body bonding portion on a paper base material, for example. A first punching step of forming a blank, a resin portion forming step of forming an intermediate layer such as a thermoplastic resin layer and a barrier layer including long windows on both sides of the paper base of the blank, and a body side end of the blank A second punching process that leaves a resin part extending outward at the edge part, and further provides a notch on the upper edge of both side edges of the blank and punches the outer dimension into a sheet for blanking; and If necessary, the outwardly extending resin part is folded back to the outside or inside of the paper base, and a folding step (see FIGS. 8 and 9) and the side edge where the blank resin part is formed, Overlap and adhere closely to the inside of the other side edge, A body forming step, and a bottom forming step of integrating a bottom member obtained by punching a paper-based laminate having a thermoplastic resin layer at least on the inner surface into a predetermined shape at the bottom of the body. The upper end edge of the body part is wound one or more times to form a flange part, and a flattening process for flattening the upper surface of the wound flange part by, for example, ultrasonic waves.
The cup-shaped paper container is further filled with contents, and then a lid is bonded to the flange by hot pressure or the like, and then retort sterilized to obtain a product.

An embodiment of the present invention will be described in detail below. Since the feature of the present invention lies in the limitation of the thermoplastic resin used in the resin part forming step, the description will focus on the laminate provided with the thermoplastic resin layer, and the others will be omitted as necessary.
The paper container of this invention is comprised from the laminated body (3) which makes the base material (1) the paper in which the thermoplastic resin layer (40) was provided in both sides | surfaces, for example.

  As shown in FIG. 1, the body member (18) has one end edge (11) on the other end of the body member blank (10) provided with notches (31) and (32) at the upper ends of both side edges. The body part bonding part (15) is formed so as to overlap with the end edge (12) of the cylinder to form a cylindrical shape.

Further, the bottom member (20) is circular and has a peripheral edge portion (21) erected downward.
And the outer surface of the peripheral part (21) of a bottom member (20) is joined to the lower inner surface of the said trunk | drum member (18).
Further, the lower end edge portion of the body member (18) is bent inward so as to cover the peripheral edge portion (21) and joined to the inner surface of the peripheral edge portion (21) of the bottom member to form the annular leg portion (22).

  On the other hand, the upper peripheral edge of the body member is wound outward one or more times to form a cup-shaped paper container in which the flange portion (16) is formed.

  Such a structure is not limited to a tapered cup-shaped paper container, and the same applies to a cylindrical cup-shaped paper container. Moreover, the structure of the trunk | drum bonding part of a trunk | drum member blank is applicable when ensuring the barrier property with respect to a paper base material also in a prismatic paper container.

  And as shown in FIG. 3, as for a trunk | drum member blank (10), one edge (11) has a thermoplastic resin layer (40) extended outward from the side edge of a paper base material (1). An extended resin part (4a) is formed.

  The thermoplastic resin layer (40) extending outward from the side edge of the paper substrate (1) is usually formed by forming a long window-like hole in a portion corresponding to the side edge of the body member blank and then paper. A thermoplastic resin that can withstand the retort sterilization temperature, such as polypropylene resin, is formed by extrusion from both sides of the substrate (1), and then punched into a predetermined shape.

In a conventional retort paper container using a polypropylene resin as the thermoplastic resin layer, a phenomenon such as foaming of moisture in the paper base material when extruded directly on the surface of the paper base material due to the high extrusion temperature of the polypropylene resin. In many cases, inconveniences such as delamination between layers occur.
When a normal low density polyethylene resin for extrusion is used instead of this polypropylene resin, the adhesion to the paper base material is ensured, but due to lack of heat resistance, peeling between layers during molding or retort sterilization, etc. Could cause inconvenience.

For this purpose, conventionally, a film in which a polypropylene resin and, for example, a PET film are laminated is interposed on a surface directly bonded to a paper substrate, and a barrier film or the like disposed on the outside thereof can be bonded by extrusion of the polypropylene resin. It was.
However, in this method, the number of layers constituting the laminate increases, and the rigidity of the laminate increases, and processing such as punching of the body member blank and bending of the thermoplastic resin layer at the time of subsequent edge bonding is performed. It became difficult and sometimes hindered the molding of paper containers.

  As a result of diligent research, the present inventor has limited the melting point and melting point peak as a thermoplastic resin that can be directly bonded to the paper base material by an extrusion method in order to simplify the processing steps and configuration of the laminate used in the paper container. It has been found that this problem can be solved by using a polyethylene resin, and the present invention has been completed.

  The laminated body used for the paper container of the present invention is a cylinder in which one side end edge is overlapped with the other side end edge to form a body bonded portion, and the upper end edge is wound one or more times to form a flange portion. In a laminate comprising a paper base used for a paper container having a cylindrical body member and a bottom container integrated with a bottom member of the body member, at least a thermoplastic resin layer is provided on both sides of the paper base, and the thermoplastic resin A layered product using a layer of polyethylene (EXPE) resin having a melting point of 122 ° C. or higher formed by an extrusion method as a layer.

  Furthermore, it is desirable that the polyethylene resin used for the thermoplastic resin layer has a density of 0.928 or more, a single melting point peak, and a broad molecular weight distribution. As a result, a polyethylene resin having a high melt viscosity and a small neck-in and good extrudability can be obtained. A single melting point peak means that there is no blend of low melting point resins usually done to improve extrudability.

  As a layer constituting the thermoplastic resin layer (40) provided on the edge (11) of the body member blank (10) shown in FIG. 2, in addition to the above-mentioned extrusion polyethylene (EXPE) resin, Several layers can be provided to reinforce the mechanical strength of the outer surface and the inner surface and to enhance barrier properties such as oxygen and water vapor.

  The resin portion (4a) extending from the end portion shown in FIG. 3 not only extends outward from the end portion of the paper base material (1), but also as shown in FIG. ) In the vicinity of the paper substrate (1), it is preferable that the folded resin portion (4b) be folded back. Thus, by setting the resin part (4b) to the outer surface side of the substrate (1), the amount of resin in the bonding part (15) can be secured, and the sealing property of the bonding part is good. Become. At the same time, the barrier properties of the base material and the end face of the resin part can be enhanced.

  In FIG. 4, the resin portion (4c) extending from the end portion extends not only outward from the end portion of the base material (1), but also in the vicinity of the base material (1) as shown in the figure. Then, the case where it was set as the structure of the folding | returning resin part (4d) folded by the inner surface side of the base material (1) was shown. Thus, by setting the resin portion (4d) to be folded back to the inner surface side of the base material (1), the amount of resin in the bonding portion (15) can be secured, and the sealing property of the bonding portion is good. Become. At the same time, the barrier properties of the base material and the end face of the resin part can be enhanced.

  In the cup-shaped paper container of the present invention having such a structure, the end surface of the paper base material positioned inside the body portion bonding portion (15) has a resin portion (4a) or a folded resin portion (4b). Therefore, the contents filled in the container do not penetrate from the end face of the paper base material.

  As shown in FIG. 3, the thermoplastic resin layer (40) is usually provided not only on the inner surface side but also on the outer surface side. Thus, by providing the thermoplastic resin layers (40) and (41) on both sides of the paper substrate, the resin part (4a) formed on the end surface of the substrate becomes the thermoplastic resin layers (40) (40) ( 41) is formed in an integrated state at the outer edge.

  In the example shown in FIG. 4, in the trunk member blank (10), one end edge (11) located on the container inner surface side in the trunk portion bonding portion (15) is a thermoplastic resin layer ( 40) and the resin part (4a) in which the thermoplastic resin layer (41) on the outer side of the paper base extends outward from the side edge of the paper base (1) in the vicinity of the base (1). And it is set as the structure provided with the folding | returning resin part (4b) folded by the outer surface side of the base material (1).

  Further, the other edge (12) located on the outer surface side of the container in the body bonding portion (15) includes the thermoplastic resin layer (40) on the inner surface side of the paper substrate and the thermoplastic resin on the outer surface side of the paper substrate. The layer (41) folded the resin part (4c) extending outward from the side edge of the paper substrate (1) to the outer surface side of the substrate (1) in the vicinity of the substrate (1). The folded resin portion (4d) is provided.

  As described above, the resin portion (4b) has a configuration in which the resin portion (4a) is folded back to the outer surface side of the base material (1), so that the amount of resin in the body portion bonding portion (15) can be secured, and the resin portion (4b) is bonded. The sealing property of the inner surface of the mating part is improved.

Moreover, the resin part (4d) can ensure the resin amount in the trunk | drum bonding part (15) by setting it as the structure which turned the resin part (4c) to the outer surface side of the base material (1), and bonded part The sealing property of the outer surface is good. The end portion of the resin portion (4a) and the end portion of the resin portion (4c) may be a gap or may overlap.
Or although not shown in figure, the resin part (4d) can also be set as the structure which turned up the resin part (4c) to the inner surface side of the base material (1).

  Furthermore, depending on the degree of necessity of edge protection to the outside of the body bonding portion, as shown in FIG. 3, the other end of the paper substrate located on the outer surface side of the container in the body bonding portion (15). The edge (12) has a thermoplastic resin layer (40) on the inner side of the paper base and a thermoplastic resin layer (41) on the outer side of the paper base extending outward from the side edge of the paper base (1). The taken out resin part (4c) can also be made into the structure which piled up and crimped | bonded to the thermoplastic resin (41) of the outer surface side of the base material (1) of the container inner surface side.

  In the cup-shaped paper container of the present invention having such a structure, the end surface of the paper base material located inside the trunk portion bonding portion (15) is protected by the folded resin portion (4b), Since the end surface of the paper base material located outside the body bonding portion (15) is protected by the folded resin portion (4d) or the resin portion (4c) sealed by thermocompression bonding, the container is filled. In addition, not only the content does not permeate from the end surface of the paper base material, but also an edge protection effect that prevents permeation from the outside of the container.

  Furthermore, a thermoplastic resin layer (40), (41) is provided on both sides of the paper substrate, and a polyethylene terephthalate or nylon layer having excellent heat resistance and abrasion resistance is formed in the layer structure of the thermoplastic resin layer on the outer surface. By providing, it is possible to effectively prevent water penetration from not only the edge of the paper substrate but also the surface pinholes.

Thus, by providing the thermoplastic resin layers (40) and (41) on both sides of the paper substrate, the resin portions (4a) and (4c) extending to the end surface of the substrate become the thermoplastic resin layers on both sides. (40) (41) is formed in an integrated state at the outer edge.
And the said resin part (4a) is set as the structure of the folding | returning resin part (4b) folded back to the outer surface side of a paper base material instead of the structure extended outward from the edge of a paper base material as mentioned above. In addition, the resin part (4c) extends outward from the edge of the paper base and is thermocompression bonded, or the folded resin part (4d) is folded back to the outer or inner surface of the paper base. And

  Thus, by setting the bonded resin portion of the barrel member on the inner surface side of the container to the configuration of the folded resin portion (4b) that is folded back to the outer surface side or the inner surface side of the base material, the level difference of the barrel bonded portion is The folded resin portion (4b) can be buried and have no step, and the paper substrate (1) and the end surface of the resin portion can be configured not to be exposed inside the paper container.

In addition, by forming the resin part (4c) outwardly extending from the edge of the paper base and thermocompression bonding, the step of the body part bonding part is filled with the outer resin part (4c). Moreover, it can be set as the structure without a level | step difference, and can be set as the structure which a paper base material (1) does not expose to a paper container exterior.
Further, by forming the resin part (4c) as a folded resin part (4d) that is folded back from the edge of the paper base to the outer surface side of the paper base, the step of the body laminating part is the folded back. The resin portion (4d) is filled with a step and there is no step, and the paper base (1) and the end surface of the resin portion are not exposed to the outside of the paper container.

  The cup-shaped paper container of the present invention is usually provided with a flange portion (16), and at the upper end of the bonded portion (15) of the body member (18), notches are formed at the upper portions of both side edges. When the body member blank (10) provided with the parts (31) and (32) is used, the upper peripheral edge of the body member is wound outward one or more times to form a flange portion having at least a triple structure. Also in the part, the base material is in a wrap-up state with the same triple structure as the part other than the bonded part.

  Further, by configuring the resin portion (4b) by folding the resin portion (4a) including the barrier layer, the end surface of the barrier layer (2a) is not exposed to the inside of the container, and the content is the barrier layer. It can be prevented from touching and does not adversely affect the storage of the contents.

As described above, the folded resin portions (4b) and (4d) are configured such that the tip of the resin portion is folded back to the bonded portion inner base material outer surface side or the bonded portion outer base material outer surface side or the inner surface side. Thus, even when the thermoplastic resin layer (40) includes a barrier layer (2a) made of a different material, when the body portion is formed, the body portion bonding portion (15) is fixed for bonding. In addition to protecting the end face of the paper base material (1), the level difference due to the paper base material of the body part bonding portion (15) can be eliminated.
Here, even if the upper surface of the flange portion (16) having at least a triple structure is flattened by making the shape of the notches (31) and (32) different, the bonded portion is formed on the upper surface of the flange portion. The level difference that occurs at the position of can be eliminated.

  In the paper container of this invention, the said thermoplastic resin layer (40) can also be set as the structure made into a layer containing a barrier layer. Thus, by setting it as the structure containing a barrier layer (2a), since the surface and end surface of a paper base material (1) are also protected by a barrier layer, it can be set as a cup-shaped paper container excellent in barrier property. .

Further, by configuring the resin portion (4b) by folding the resin portion (4a) including the barrier layer, the end surface of the barrier layer (2a) is not exposed to the inside of the container, and the content is the barrier layer. It can be prevented from touching and does not adversely affect the storage of the contents.

  As described above, the folded resin portions (4b) and (4d) are configured such that the tip of the resin portion is folded back to the bonded portion inner base material outer surface side or the bonded portion outer base material outer surface side or the inner surface side. Thus, even when the thermoplastic resin layer (40) includes a barrier layer (2a) made of a different material, when the body portion is formed, the body portion bonding portion (15) is fixed for bonding. In addition to protecting the end face of the paper base material (1), the level difference due to the paper base material of the body part bonding portion (15) can be eliminated.

  Next, an example of the manufacturing method of the paper container of this invention is demonstrated including the manufacturing method of a trunk | body member blank.

  First, a plurality of fan-shaped body member blanks (10) are arranged and printed on a roll-shaped paper base material (1), and both ends (11) and (12) of the body member blank are connected to the end thereof. A first punching step is performed by drilling the outer portions including the edges as long windows (13) and (14) (see FIGS. 5A and 5B).

Next, the body blank (10) is printed and the thermoplastic resin layer (40) is formed on the inner surface of the paper base (1) in which the long windows (13) and (14) are perforated, and the thermoplastic is formed on the outer surface. A resin layer (41) is formed.
The thermoplastic resin layer formed on the inner surface consists of a CPP // barrier film // EXPE / EXPE layer from the inside, and a pre-prepared film of CPP // barrier film // EXPE is affixed to the paper substrate with EXPE Match.
The thermoplastic resin layer formed on the outer surface side is composed of a CPP // PET // EXPE / EXPE layer from the outside, and a pre-prepared film of CPP // PET // EXPE is bonded to a paper substrate with EXPE. Create a laminate.

The layer structure of this laminate is (CPP // PET // EXPE) / EXPE // paper substrate // EXPE / (EXPE // barrier film // CPP) from the outside (see FIG. 2 (A)). Compared to the case where EXPP is used for extrusion lamination (see Fig. 2 (B)) by using a specific EXPE that can secure adhesion even when extruded directly onto the substrate and is resistant to heating during retort sterilization. Manufacture with a simple configuration and process is possible, and since it is easy to bend even in the processing step after blank production, stable processing can be performed.
In the thermoplastic resin laminating process at this time, the resin portions (4a) and (4c) in which the thermoplastic resin layers are laminated are also formed on the long window portion of the paper substrate (1) (FIG. 6A). ), (B)).

Next, a cylinder blank (10) in which a long window portion including resin portions (4a) and (4c) provided outwardly extending from the paper substrate (1) of the laminate is formed in the second punching step. ) Unnecessary parts are continuously cut.
At the same time, a plurality of printed fan-shaped body member blanks (10) are punched out of the laminate from which unnecessary portions have been cut out, and each body member is formed with resin portions (4a) and (4c). A blank (10) is produced (see FIGS. 7A and 7B).

  A body member blank (10) in which the resin portions (4a) and (4c) extending outward by a predetermined width from the paper substrate (1) through these steps are formed on both side edges is produced. be able to.

The paper base layer (1) is not particularly limited as long as it is used as a normal cup base paper. However, the paper base layer (1) has printability and paper strength, excellent formability, and strong surface strength. Amount 10
Those of about 0 to 500 g / m ² are preferably used.

  The film thickness of the sealant layer constituting the thermoplastic resin layer (41) on the outer side of the container and the sealant layer constituting the thermoplastic resin layer (40) on the inner side of the container is usually 10 μm to 60 μm. It can be provided by a known method such as dry lamination.

  As the barrier layer (2a), a vapor-deposited layer of a metal such as aluminum or an inorganic oxide such as silica, alumina, zinc oxide, tin oxide, magnesium oxide, or the like, a stretched polyester resin film such as a stretched polyethylene terephthalate resin film, or stretched nylon A vapor deposition film provided on a stretched polyamide resin film such as a resin film can be used.

  Next, an example of a method for forming the resin part (4a) of the body member blank (10) on the paper base end face (5) will be described with reference to FIGS.

  The resin layer (4a) extending by a predetermined width from the paper base (1) of the body member blank (10) is directed toward the outer surface side of the paper base (1) when formed into a paper cup. The first member (D1) having the pressing protrusion (D11) formed in a comb shape is vertically moved from the upper side to the lower side, and is pushed and bent at an angle of about 90 ° to be temporarily folded (FIG. 9A). , (B)).

  Next, the formed second member (D2) having the pressing protrusion (D21) formed in a comb shape is inserted into the gap (D12) between the pressing protrusion (D11) and the pressing protrusion (D11) of the first member. The resin part (4a) is pushed and bent by approximately 90 °, and the resin part layer (4a) includes a folded resin part (4b). In such a manner, the body member blank is temporarily folded so as to overlap the paper substrate outer side direction (see FIG. 9C).

Finally, the third member (D3) provided with the pressing protrusion (D31) formed on the lower side of the first member and having a comb shape is vertically pressed and pressure-bonded, and the folded resin portion (4b) Is temporarily adhered to the outer surface side of the paper base of the body member blank (10) (see FIG. 9D).
In addition, if the pressing protrusion (D31) of the third member is heated to an appropriate temperature, the adhesiveness of the resin portion is improved, which is more effective.

  Since an example of a molding method for molding a cup-shaped paper container using the body member blank (10) produced by such a method has already been described, the description thereof is omitted here.

  As for the decoration of the cup-shaped paper container of the present invention, for example, a substrate provided with a decoration layer is used as a body blank by printing or the like on the surface of the paper substrate, and a paper container is manufactured, or the surface side of the paper substrate A method of manufacturing a paper container using a laminated material obtained by laminating a plastic film provided with a decorative layer and / or a metal vapor-deposited layer by printing, etc., or by printing or metal vapor deposition on the surface of a molded paper container It can apply by the method of coat | covering the plastic film which gave the decoration layer.

<Example 1>
A retortable CPP film (Toray ZK207, thickness 50 μm) and a PET film (Toyobo E5200, thickness 12 μm) were bonded together by a dry lamination method using an adhesive (Mitsui Takeda Chemical A626 (main agent) A50 (curing agent)).
Adhesives (A626 and A50) were applied as anchor materials to the bonded CPP / PET film, and PE resin (Tosoh 09S57D) was extruded to produce a CPP // PET // EXPE (extruded PE) film.

A retortable CPP film (Toray ZK207 thickness 50 μm) and a barrier film (GL film; GLARH thickness 12 μm) were bonded together by an adhesive (Mitsui Takeda A626 (main agent) A50 (curing agent)) by a dry lamination method. .
Adhesives (A626 and A50) were applied as anchor materials to the bonded CPP // GL film, and PE resin (Tosoh 09S57D) was extruded to prepare a CPP // barrier film // EXPE (extruded PE) film.

  A hole for forming only the film part for protecting the end face is formed on the paper, and the two kinds of films are bonded to both surfaces of the paper with the hole by the sand lamination method, and (CPP // A laminate having a layer structure of PET // EXPE) / EXPE // paper // EXPE / (EXPE // barrier film // CPP) was prepared. As EXPE for sand lamination, Tosoh 09S57D was used.

  A cup was molded using the laminated body having the configuration for the retort container as a body member. There was no particular problem with moldability. The cup was filled with the contents, sealed with a lid, and sterilized by retort at 121 ° C. for 30 minutes, but the problem that the cup was broken did not occur without peeling between layers.

<Example 2>
A retortable CPP film (Okamoto U thickness 50 μm) and a PET film (Toyobo E5200 thickness 12 μm) were bonded by a dry lamination method using an adhesive (Mitsui Takeda Chemical A626 (main agent) A50 (curing agent)).
Adhesives (A626 and A50) were applied as anchor materials to the bonded CPP / PET film, and PE resin (Tosoh 11S53A) was extruded to produce a CPP // PET // EXPE (extruded PE) film.

A retortable CPP film (Okamoto U thickness 50 μm) and a barrier film (GL Besela thickness 13 μm) were bonded together by an adhesive (Mitsui Takeda Chemical A626 (main agent) A50 (curing agent)) by a dry lamination method.
Adhesives (A626 and A50) were applied as anchor materials to the bonded CPP // barrier film, and PE resin (Tosoh 11S53A) was extruded to produce a CPP // barrier film // EXPE (extruded PE) film.

  A hole for forming only the film part for protecting the end face is formed on the paper, and the two kinds of films are bonded to both surfaces of the paper with the hole by the sand lamination method, and (CPP // A laminate having a layer structure of PET // EXPE) / EXPE // paper // EXPE / (EXPE // barrier film // CPP) was prepared. As EXPE for sand lamination, Tosoh 11S53A was used.

  A cup was molded using the laminated body having the configuration for the retort container as a body member. There was no particular problem with moldability. The cup was filled with the contents, sealed with a lid, and sterilized by retort at 121 ° C. for 30 minutes, but the problem that the cup was broken did not occur without peeling between layers.

<Comparative Example 1>
A retortable CPP film (Okamoto U thickness 50 μm) and a PET film (Toyobo E5200 thickness 12 μm) were bonded by a dry lamination method using an adhesive (Mitsui Takeda Chemical A626 (main agent) A50 (curing agent)).

Adhesives (A626 and A50) were applied as anchor materials to the bonded CPP / PET film, and PE resin (Tosoh LW04-1) was extruded to produce a CPP // PET // EXPE (extruded PE) film.
A retortable CPP film (Okamoto U thickness 50 μm) and a barrier film (GL Besela thickness 13 μm) were bonded together by an adhesive (Mitsui Takeda Chemical A626 (main agent) A50 (curing agent)) by a dry lamination method.

Adhesives (A626 and A50) were applied as anchor materials to the bonded CPP // barrier film, and PE resin (Tosoh LW04-1) was extruded to produce a CPP // barrier film // EXPE (extruded PE) film. .
A hole for forming only the film part for protecting the end face is formed on the paper, and the two kinds of films are bonded to both surfaces of the paper with the hole by the sand lamination method, and (CPP // A laminate having a layer structure of PET // EXPE) / EXPE // paper // EXPE / (EXPE // barrier film // CPP) was prepared. LEX04-1 from Tosoh was used as EXPE for Sandra lamination.

A cup was molded using the laminated body having the configuration for the retort container as a body member. There was no particular problem with moldability.
The cup was filled with the contents, sealed with a lid, and sterilized by retort at 121 ° C. for 30 minutes. However, part of the layers collapsed and crushing like bubbles occurred. It is considered that Tosoh's LW04-1 used as the extruded PE resin is blended with LDPE in order to increase the extrusion moldability.

DESCRIPTION OF SYMBOLS 1 ... Paper base material 2a ... Barrier layer 3 ... Laminated body 4a ... Resin part 4b extended outward ... Folded resin part 4c folded in the outer surface side ... Resin part 4d extended from the edge part ... Folded in the inner surface side Folded resin part 5 ... Paper base material end face 10 ... Body member blank 11 ... One end edge 12 of the body member blank ... Other end edge 13 of the body member blank ... Long window 14 ... Long window 15 ... Body part bonding part DESCRIPTION OF SYMBOLS 16 ... Flange part 18 ... Body member 20 ... Bottom member 21 ... Peripheral part 22 of bottom member ... Ring leg part 31 ... Notch part 32 ... Notch part 40 ... Thermoplastic resin layer 41 ... Thermoplastic resin layer D1 ... Holding protrusion A first member D11 having a pressing protrusion D2 formed in a comb shape, a second member D21 having a pressing protrusion, a pressing protrusion D12 formed in a comb shape, a gap D3 between pressing protrusions, and a first protrusion having a pressing protrusion. 3 members D31 are formed in a comb shape Holding projections

Claims (8)

A laminate that includes a paper substrate and is used for a body member of a paper container,
The paper container is configured to include the cylindrical barrel member and a bottom member integrated with a lower portion of the barrel member, and the barrel member has one side edge of the laminate as the other. In the laminated body, which is formed in a cylindrical shape by being overlapped with the side edge, and the upper end edge is wound one or more times to form a flange portion.
The paper substrate is provided with a thermoplastic resin layer on both sides, the thermoplastic resin layer has a multilayer structure including a polyethylene resin layer, and the polyethylene resin layer has a melting point of 122 ° C. or higher. A laminate comprising a polyethylene resin and formed by an extrusion method.   The laminate according to claim 1, wherein the polyethylene resin layer does not contain a linear low-density polyethylene resin having a melting point of less than 122 ° C.   The laminate according to claim 1 or 2, wherein the polyethylene resin is a polyethylene resin having no plurality of melting points.   The laminate according to any one of claims 1 to 3, wherein the density of the polyethylene resin is 0.928 or more.   The thermoplastic resin layer having a multilayer structure is formed by laminating another multilayer film on the polyethylene resin layer, and this multilayer film is a multilayer film in which an unstretched polypropylene film and a polyethylene terephthalate film are bonded together in advance. 5 or a multilayer film in which a barrier film, an unstretched polypropylene film, and an extruded polyethylene layer are bonded to each other.   The laminated body according to any one of claims 1 to 5, wherein a polyethylene terephthalate film, a nylon film, or a barrier film is laminated in the layer structure.   The laminate according to claim 6, wherein the barrier film is a film obtained by depositing an inorganic oxide or a metal on a base film, and the base film is a polyethylene terephthalate film or a nylon film.   A paper container for retort using the laminate according to any one of claims 1 to 7.

Images