JP2725047B2 - Lamination method by hot press - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a laminated sheet used as a molding material for a packaging material, for example, a box-paper container filled with liquid or powder.

(Prior Art) Conventionally, paper containers for filling liquids or powders such as juice and sake usually form an adhesive portion by a heat-sealing ability of a laminated sheet as a molding material. In general, the laminated sheet is formed of a polyolefin-based resin layer on the side of the inner surface layer of the container on the side in contact with the contents, and an adhesive portion is formed by the heat-sealing ability of the polyolefin-based resin layer to form a paper. The container is molded.

(Problems to be Solved by the Invention) By the way, in the above-described conventional laminated sheet in which a portion serving as an inner surface layer of the container is entirely formed of a polyolefin-based resin layer, aliphatic carbonization is caused by thermal decomposition of the polyolefin-based resin during molding of the container. Volatile components such as hydrogen are generated and mixed with the contents, which causes deterioration in quality such as deterioration of taste. In addition, the polyolefin resin layer absorbs and elutes the components such as orange juice as the contents. This causes a problem that the quality of the contents is also deteriorated.

In view of this, the present applicant has proposed that, in a blank plate for a box-shaped paper container made of a laminated sheet, the back surface layer that is in contact with the contents is made of a resin layer with little adsorption and elution of the contents to be filled,
For example, it is composed of a stretched polyester resin film layer, a stretched ethylene-vinyl alcohol-based copolymer resin film layer, a polycarbonate resin layer, and the like. It has been proposed to laminate a film of a heat sealing resin having heat sealing properties, for example, a polyethylene resin. However, as in the case of a blank plate for a box-shaped paper container, a heat-sealing resin film is laminated on a back surface peripheral portion which is an adhesive portion of a sheet formed of a stretched polyester resin film or the like. A major problem was how to ensure the bonding strength between the back layer composed of a stretched polyester resin film layer and the like and a resin film for heat sealing such as a polyethylene resin film. The laminating means includes, for example, dry lamination and extrusion lamination. However, these conventional methods cause adverse effects due to high temperatures or require a large amount of adhesive,
All of these were not satisfactory.

The present invention has been made in order to solve the above-described problems, and is intended to strongly bond and laminate a heat-sealing resin film having a heat-sealing property at a lower temperature to a back layer composed of a stretched polyester resin film layer and the like. It is an object of the present invention to obtain a simple and low-cost laminating method using a hot press.

(Means for Solving the Problems) According to the present invention, by performing hot pressing through an anchor agent, the amount of the anchor agent is small, and the resin film for heat sealing is firmly fused and laminated by hot pressing at a relatively low temperature. Focusing on the fact that the lamination can be performed, an effective lamination method using the hot press is realized. That is, in the lamination method by hot pressing of the present invention, the back layer is made of any one resin layer selected from a stretched polyester resin film layer, a stretched ethylene vinyl alcohol-based copolymer resin film layer and a polycarbonate resin layer. In the laminating method by a hot press in which the heat-sealing resin film having a heat-sealing property at a low temperature is laminated on the back surface layer of the laminated sheet at a low temperature compared to the resin constituting the back surface layer, the back surface layer and the heat-sealing resin film After applying an anchor agent to at least one of them, superposing them on each other and sending them to a hot roll, heating and pressurizing while releasing a release film between the hot roll and the heat sealing resin film, the heat sealing resin Characterized in that a film is fused and laminated to the back surface layer via an anchoring agent. Than it is.

(Effect) The back layer of the laminated sheet composed of any one resin layer selected from a stretched polyester resin film layer, a stretched ethylene vinyl alcohol-based copolymer resin film layer and a polycarbonate resin layer, and a heat to be laminated thereon. In a state where the anchor agent is applied to at least one of the sealing resin film, the back surface layer and the heat sealing resin film are overlapped and sent to a heat roll. Heating and pressurizing are performed while the releasable film is pressed between the heat roll and the heat-sealing resin film, whereby the heat-sealing resin film is fused to the back surface layer via an anchor agent. It is laminated. The release film prevents the resin film for heat sealing from adhering to the heat roll side during hot pressing.

(Example) Hereinafter, an example is described based on drawings.

FIG. 1 shows a laminated structure of a laminated sheet 11 as a packaging material according to one embodiment of the present invention. This laminated sheet 1
On the surface of acid-resistant paper 2 weighing 400 g / m ^2, a thickness of 3
A 0μ low-density polyethylene resin “Mirason 16sp” layer is formed by extrusion coating.
A 9μ-thick aluminum foil 5 is adhered using an adhesive layer 4 composed of a 30μ ionomer resin “Mitsui Depon Chemical Co., Ltd .: Himilan 1652” layer.
As the back layer 6, a biaxially stretched polyester film “Toyobo Co., Ltd .: Espet” having a thickness of 12 μm is coated with a urethane-based adhesive “Takerac A-515 ... 10 manufactured by Takeda Pharmaceutical Co., Ltd.
Parts by weight, Takenate A-50: 1 part by weight, ethyl acetate: 8
Parts by weight) and a coating amount of 3.5 g (DRY) / m ² ". The acid-resistant paper 2, the adhesive layer 4 and the aluminum foil 5 form the intermediate layer 7 of the laminated sheet 1.

The stretched polyester film is made of a stretched film using a polyester mixed resin to which an adhesive resin is added as a raw material for film formation, and its surface is subjected to a corona discharge treatment.

The laminated sheet 1 is punched into a rectangular sheet 1A having a predetermined size. FIG. 2 shows the back surface of the punched rectangular sheet 1A. The four sides of the back surface marked with A, B, C, and D are each provided with a thickness as a heat-sealing resin film. A 60μ polyethylene film 8 is laminated. In this example, the size of the rectangular sheet 1A is 40 cm ×
40 cm, and the width of each side portion A to D is A:
2.5 cm, B: 3.5 cm, C: 7.5 cm, D: 3.0 cm.

FIG. 3 is a schematic view of a step of laminating a polyethylene film 8 as a resin film for heat sealing on the back layer 6 made of a stretched polyester film as described above in this example.

First, in the case of FIG. 1A, the anchor agent 9 prepared as shown in Table 1 is applied to the back surface layer 6, and the corona-treated surface of the polyethylene film 8 "Dainippon Resin LP-5" is applied to the applied surface. A hot press is performed with a wettability index of 38 dyne / cm).

On the other hand, in the case of FIG. 2B, the anchor agent 9 prepared as described above is applied to the corona-treated surface of the polyethylene film 8, and the applied surface is matched with the back surface layer 6 and hot-pressed.

In the case of FIG. 3C, the anchor agent 9 is applied to both the back surface layer 6 and the polyethylene film 8, and hot pressing is performed with both applied surfaces together.

Either of these methods allows lamination of the polyethylene film 8 on the back layer 6 made of a stretched polyester film.

Table 2 shows that a stretched polyester film (PE
In this example using T), and in another example using a stretched ethylene vinyl alcohol copolymer film (EVAL) or polycarbonate (PC) for the back layer, after the hot pressing, the distance between the back layer and the polyester film was reduced. of
It is the result of measuring the lamination strength (g / 15 mm) at 180 ° peeling. In each case, the heat press used Nakamori Kogyo N-RS as a heat press machine, temperature: 200 ° C., pressure: 100 kg, speed 30 m /
The test was performed under heat press conditions of min. From this measurement result, when the back layer is PET, isocyanate-based
Urethane type, polyethyleneimine type, etc. are suitable, and when the back layer is EVAL, the same anchoring agent as for PET is used.
In the case of PC, a polyethyleneimine-based anchor agent was found to be suitable. In the case where the back layer is made of PC, that is, polycarbonate, it is not possible to obtain a sufficient bonding strength by applying the anchor agent 9 only on one side as shown in FIG. 3 (a) or (b). It is necessary to apply an anchoring agent to both the back layer 6 made of polycarbonate and the polyethylene film 8 as described above.

Lamination of the polyethylene film 8 on the back surface layer 6 of the rectangular sheet 1A is performed first on the parallel side portions A and B. After the lamination of these side portions A and B is completed, these side portions A and B Other parallel side parts C and D including the overlapping part with
Similarly, the polyethylene film 8 is laminated. Therefore, the polyethylene film 8 is double-layered at a portion where one of the parallel side portions A and B and the other parallel side portion C and D overlap.

FIG. 4 is a schematic diagram of a hot pressing method for laminating the polyethylene film 8 described above. As shown in this figure, the heat press device 10 includes a rubber heat roll 11 and a metal roll 12, which are arranged to face each other vertically and rotate in opposite directions to each other,
And a heater 13 for heating the heat roll 11. Then, between the upper heat roll 11 and the lower metal roll 12, a rectangular sheet 1A having a back surface facing upward and a polyethylene film 8 to be laminated on the back surface are superposed and fed. An anchor agent is applied to at least one of the back surface of the rectangular sheet 1A and the bottom surface of the polyethylene film 8. And the above rectangular sheet
1A is fed horizontally, the polyethylene film 8 is sent from above via a guide roll 14, and a biaxially stretched polyester film 15 is bitten between the rubber roll 11 and the polyethylene film 8 as a release film. It has a configuration.

The rectangular sheet 1A is thereafter formed with a pressing pressure line for folding at the time of box making, and is then punched into a predetermined shape and molded into a blank plate for a box-shaped paper container. Then, a necessary end face treatment is performed on one side part A which is a side of the blank plate, and the opposite side part B is superimposed on the side part A on which the end face treatment has been performed, and is thermally welded by a flame sealing method. Thus, a rectangular cylinder is formed. Also, a portion of the blank plate corresponding to the bottom of the container is bent, and the overlapped portion is thermally welded to form the bottom of the container. Then, a spouting tool is attached to the rectangular cylinder, and after the contents (for example, orange juice 1800 ml) are filled, the portion corresponding to the top of the container is bent using the bending pressing line, The overlapping portion is heat-welded and molded into a box-shaped paper container.

In the above embodiment, PE (30 μ) / paper (400 g / m ² )
/ Surlyn (30μ) / Al (9μ) / Stretched PET (12μ) Laminated sheet with PE (60μ) film on each of the four sides on the back side, but the present invention It can be applied to a combination of a sheet and a laminated film. Table 3 shows combinations of the laminated sheet and the film in various examples including the case (1) of the above example.

Further, the lamination method according to the present invention is not limited to laminating a heat-sealing film on a laminated sheet, but also laminating a laminated film having a polyethylene film layer as a back layer on a laminated sheet having a stretched polyester resin film layer or the like as a back layer. The present invention can also be applied to the case where it is performed.

In addition, this laminating method can provide good results even when used as a means for bonding laminated films having a back surface layer of a polyethylene film layer.

(Effect of the Invention) Since the present invention is configured as described above, the back surface layer of the laminated sheet may be formed of any one of a stretched polyester resin film layer, a stretched ethylene vinyl alcohol copolymer resin film layer, and a polycarbonate resin layer. It is composed of one resin layer, and a heat-sealing resin film having heat sealing property at a lower temperature can be firmly bonded and laminated on this back layer. In this case, heat sealing is achieved by the interposition of a release film. Adhesion of the resin film for heating to the heat roll can be prevented. In addition, only a small amount of the anchor agent is used, and sufficient bonding strength can be obtained by hot pressing at a relatively low temperature.

The present invention is particularly effective as a means for partially laminating a heat-sealing resin layer on a sheet, and a blank plate obtained by this method is a surface which comes into contact with the contents when easily molded. Can be constituted by a resin layer with little adsorption and elution of the content to be filled, so that the quality of the content can be prevented from deteriorating.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a laminated sheet according to an embodiment of the present invention, FIG. 2 is a back view of a punched rectangular sheet before being punched into a blank plate in the embodiment, and FIG. FIG. 4 is a schematic view of a step of applying an anchor agent, and FIG. 1: Laminated sheet, 6: Back layer, 8: Polyethylene film (resin film for heat sealing), 9: Anchor agent, 10: Heat press device, 11: Heat roll, 15: Biaxially stretched polyester film (release film) ).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29L 9:00

Claims (1)

(57) [Claims] 1. A backsheet of a laminated sheet comprising a resin layer selected from a stretched polyester resin film layer, a stretched ethylene vinyl alcohol-based copolymer resin film layer and a polycarbonate resin layer. In a laminating method by hot pressing for laminating a heat sealing resin film having a heat sealing property at a low temperature compared to a resin constituting the back layer, an anchor is provided on at least one of the back layer and the heat sealing resin film. After applying the agent, these are superimposed and sent to a hot roll, and heated and pressurized while biting a release film between the hot roll and the heat sealing resin film, the heat sealing resin film By hot pressing characterized by being fused and laminated to the back layer via the anchor agent Laminate-way.