JP2007230592A - Paper container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper container which has a printed layer excellent in glossiness, and of which the bonding at the time of molding can easily be performed. <P>SOLUTION: A container shape is formed by using a laminated sheet 11, and the problem of bondability is solved by making the front and the rear of the side seam 11c the same resin layer. In this case, the laminated sheet 11 is composed of a laminate of at least a drawn high-density polyethylene film layer 12 which is formed on the surface, a rear surface printed layer 13 which is printed on the rear surface of the drawn high-density polyethylene film layer 12, a stencil paper layer 14 which is bonded to the rear surface printed layer 13 of the drawn high-density polyethylene film layer 12, and a polyethylene film layer 17 which is formed on the rear surface of the stencil paper layer 14. Thus, the paper container which has the printed layer 13 excellent in glossiness and can be molded and bonded without inviting the increase of processes is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper container, and can provide a paper cup provided with a printed layer having excellent gloss.

  For example, when molding a paper cup, which is one of the paper containers, with a printed layer on its surface, prepare a laminated sheet with the printed layer, polyethylene layer, paper layer, and polyethylene layer laminated from the front side. After making a fan-shaped body blank and a bottom plate blank from this laminated sheet, winding the body blank to form a truncated cone, and bonding the two side edges together, the lower end opening The bottom plate is attached so that the peripheral edge of the bottom plate overlaps the inside of the body part, and the curled part is formed by winding the upper end opening edge outward, and the inner side of the paper cup is a problem of leakage. From the polyethylene layer.

  Moreover, in the paper container which requires gas barrier property, an aluminum foil and a polyethylene terephthalate layer are added to the inside of the paper layer of the above-mentioned laminated sheet and are laminated through an adhesive.

  In such a paper container, a printing layer is provided on the outer surface of the laminated sheet in both cases of a normal paper cup and a gas barrier paper container, and this printed layer is made of polyethylene outside the paper layer of the laminated sheet. It was formed by printing directly on the layer, but when printing directly on the polyethylene layer, the surface gloss is poor and the design is poor.

  Therefore, in Patent Documents 1 and 2, a transfer sheet having a release layer, a printing layer, and an adhesive layer provided on a transfer sheet substrate is prepared, and after extruding and laminating the polyethylene sheet on the surface of the laminated sheet, the release layer is removed. Thus, a printed layer having excellent gloss is formed on the surface of the polyethylene layer.

In addition, as a method of forming a printed layer having excellent gloss, printing is performed on the back side of the film, and this is bonded to the surface of the paper layer. A biaxially stretched polyethylene terephthalate film or a biaxially stretched polypropylene film is used. And a printing layer is provided on the back surface of the paper layer and laminated with the paper layer.
JP 2004-352364 A Japanese Patent No. 3594748

  However, when a transfer sheet is used, a biaxially stretched polyethylene terephthalate film or a biaxially stretched polypropylene film is used as a transfer sheet substrate, and the surface is a resin layer other than a polyethylene layer, as in the case of laminating a back printed film. Therefore, when the container is molded, if it is intended to join the polyethylene layer inside the paper container of the seam portion, there is a problem that it cannot be mass-produced as it is.

  For this reason, it is necessary to apply an adhesive to the seam part, or to cut the part of the surface layer of the laminated sheet and bend the back surface layer to make the surface layer side to join the polyethylene resin layers together. There is a problem that it is difficult to increase the number of processes or to obtain a stable adhesive force because only the skived portion is adhered.

On the other hand, when trying to print on the back side of the same polyethylene film layer as the container inner layer, the film tends to expand and contract, print misalignment occurs, clean printing is impossible, especially when multicolor printing is attempted, it is more difficult. is there.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a paper container that includes a printed layer having excellent glossiness and can be easily bonded during molding.

  The paper container according to claim 1 of the present invention for solving the problems of the prior art is a paper container in which a laminated sheet is formed and a seam is adhered, and a stretched high-density polyethylene film layer disposed on the surface, and the stretched At least a back printed layer printed on the back of the high density polyethylene film layer, a base paper layer bonded to the back printed layer of the stretched high density polyethylene film layer, and a polyethylene film layer provided on the back of the base paper layer are laminated at least. The laminated sheet is formed into a container shape and bonded with a seam.

  According to this paper container, it is a paper container in which a laminated sheet is formed and a seam is adhered, and a stretched high-density polyethylene film layer disposed on the surface and a back surface printing printed on the back surface of the stretched high-density polyethylene film layer Formed into a container shape using a laminated sheet formed by laminating at least a layer, a base paper layer adhered to the back surface printed layer of the stretched high-density polyethylene film layer, and a polyethylene film layer provided on the back surface of the base paper layer. The seam is adhered, and the surface layer is a stretched high-density polyethylene film layer to suppress expansion and contraction, enabling printing on the back surface, and making the front and back the same resin layer to solve the adhesive problem.

  Thus, a printed container having a glossy printing layer is provided, which can be molded and bonded without increasing the number of processes.

  According to a second aspect of the present invention, in addition to the structure of the first aspect, the back printed layer is a multicolor printed layer.

  According to this paper container, the back printed layer is a multicolored printing layer, and a multicolor printing is performed on a stretched high-density polyethylene film layer with small expansion and contraction, thereby providing a cleaner printing layer.

  Furthermore, the paper container according to claim 3 of the present invention is characterized in that, in addition to the structure according to claim 1 or 2, the stretched high-density polyethylene film layer has a thickness of 15 to 40 μm.

  According to this paper container, the stretched high-density polyethylene film layer has a thickness of 15 to 40 μm. With such a thickness, backside printing can be performed while suppressing expansion and contraction.

  Moreover, in addition to the structure in any one of Claims 1-3, the extending | stretching high-density polyethylene film layer which comprises the said laminated sheet is a uniaxial high-density polyethylene film in the paper container of Claim 4 of this invention. It is comprised and the expansion / contraction rate is 0.25% or less.

  According to this paper container, the stretched high-density polyethylene film layer constituting the laminated sheet is composed of a uniaxial high-density polyethylene film, and the stretch rate is 0.25% or less. It will be possible to print on the back side.

  According to the paper container of claim 1 of the present invention, it is a paper container in which a laminated sheet is formed and a seam is adhered, the stretched high-density polyethylene film layer disposed on the surface, and the stretched high-density polyethylene film layer. A laminated sheet formed by laminating at least a back printed layer printed on the back, a base paper layer bonded to the back printed layer of the stretched high-density polyethylene film layer, and a polyethylene film layer provided on the back of the base paper layer Since it was molded into a container shape and the seam was adhered, the surface layer could be stretched high-density polyethylene film layer to suppress expansion and contraction and to allow printing on the back surface. The problem can be solved.

  Thereby, it becomes a paper container which is equipped with the printing layer excellent in glossiness, and can be shape | molded and adhere | attached without causing an increase in a process.

  According to the paper container of claim 2 of the present invention, since the back surface printing layer is a multicolor printing layer, a more beautiful printing layer can be obtained by performing multicolor printing on a stretched high-density polyethylene film layer with small expansion and contraction. Can be made into a paper container.

  Furthermore, according to the paper container according to claim 3 of the present invention, the stretched high-density polyethylene film layer has a thickness of 15 to 40 μm or more. be able to.

  Moreover, according to the paper container of Claim 4 of this invention, the extending | stretching high-density polyethylene film layer which comprises the said laminated sheet is comprised with a uniaxial high-density polyethylene film, The expansion / contraction rate is 0.25% or less Therefore, backside printing can be performed with such a film while suppressing expansion and contraction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a partial cross-sectional view showing a part extracted and enlarged according to an embodiment in which the paper container of the present invention is applied to a paper cup.

  The paper cup 10 as the paper container is provided with a back surface printing layer on the film layer on the front side of the paper cup so that the surface gloss is excellent, and if the printing layer is multicolor printing, the design is greatly improved. It can be improved and can be easily joined with the polyethylene film layer on the inner surface side for preventing leakage necessary as a paper cup.

  In such a paper cup 10, a laminated sheet 11 is used. For example, a surface layer is a stretched high-density polyethylene film layer 12, and a back surface printed layer 13 is provided on the back surface of the stretched high-density polyethylene film layer 12. The stretched high-density polyethylene film layer 12 provided with the back printed layer 13 is bonded to the base paper layer 14 via the adhesive layer 15 or the polyethylene film layer 16 which is extrusion laminated, and the polyethylene which is extrusion laminated to the back side of the base paper layer 14. A film layer 17 is laminated.

  In this laminated sheet 11, the surface layer is a stretched high-density polyethylene film layer 12, and the low-density polyethylene film that has been used so far is used for laminating with a printing machine when the printing layer is provided and the subsequent base paper layer. The film expands and contracts in the laminator, and the printing misregistration increases. However, the use of a high-density polyethylene film increases the strength and suppresses expansion and contraction.

  However, the high-density polyethylene film is inferior in transparency, and glossiness and design properties cannot be effectively used even when printed on the back side.

  Therefore, by using the stretched high-density polyethylene film, transparency can be secured, the film strength is increased, the expansion / contraction rate is small, and the printing misregistration can be reduced.

  In addition, the stretched high-density polyethylene film is used as a conventional uniaxially stretched wrapping for candy or the like, the twisted portion does not return, or used for coin wrapping. Only the property of making it easy to tear due to the directional property has been used, and it is not used for printing on the back side of the film, especially for multicolor printing.

  The stretched high-density polyethylene film layer 12 that enables such backside printing may be either a uniaxially stretched high-density polyethylene film or a biaxially stretched high-density polyethylene film, and has film strength and transparency that allow backside printing. It only needs to be secured. Moreover, the film thickness should just have the thickness which can ensure the film intensity | strength and transparency which can be printed on the back surface at least, and if it is 15 micrometers or more, it can print. In the backside printing experiment, 6-color backside printing was performed on a film having a thickness of 15 μm of a uniaxially stretched high-density polyethylene film.

  Moreover, although the one where the expansion / contraction ratio of the film is as small as possible makes printing easier, in the above-mentioned back surface printing experiment, 6-color multi-color back surface printing was performed on a uniaxially oriented high-density polyethylene film having a thickness of 25 μm. In this case, the stretch rate of the film is 0.25% at the maximum in the feeding direction and 0.1% at the maximum in the width direction. From this result, printing is possible if the stretch rate is 0.25% or less. .

  The back surface printed layer 13 to be printed on the back surface of the stretched high density polyethylene film layer 12 can be provided by printing in the same manner as the surface printing on the conventional polyethylene, and multicolor printing is also possible.

  The stretched high-density polyethylene film layer 12 thus formed with the back printed layer 13 is laminated with a base paper layer 14 for paper cups.

  The base paper layer 14 is preferably a polyethylene film layer 17 in order to prevent leakage on the inner surface side of the paper cup 10. A low density polyethylene film is laminated in advance by an extrusion laminator, and the base paper layer 14 and the polyethylene film layer 17 are laminated. The

  The polyethylene film layer 17 on the back side of the base paper layer 14 made of this low density polyethylene film only needs to have a thickness that can be seamed so as not to cause a leakage problem when formed into the paper cup 10. Is used.

  The base paper layer 14 having the polyethylene film layer 17 laminated on the back surface is laminated with the stretched high-density polyethylene film layer 12 formed with the back surface printed layer 13 through the adhesive layer 15 of the adhesive for dry laminating, and the laminated sheet 11. It is said.

  Examples of the adhesive layer 15 include low density polyethylene (LDPE), ethylene-methyl methacrylate copolymer (EMAA), ethylene-acrylic acid copolymer (EAA), ethylene-methyl acrylate copolymer (EMA), and the like. These adhesive resins and adhesives are used.

  In place of the adhesive layer 15, the polyethylene film layer 16 is extruded between the stretched high-density polyethylene film layer 12 on which the back surface printed layer 13 is formed and the base paper layer 14, and the polyethylene film layer 17 is provided on the back side of the base paper layer 14. The laminated sheet 11 can also be formed by extruding and laminating with a tandem laminator so as to extrude.

  The polyethylene film layer 16 laminated between the base paper layer 14 and the back printed layer 13 may be a low density polyethylene film, and can be bonded to the stretched high density polyethylene film layer 12 via the back printed layer 13. Both can be bonded together, and the thickness may be about 15 μm.

The paper cup 10 using such a laminated sheet 11 produces a fan-shaped blank for the body portion 10a and a circular blank for the bottom portion 10b from the laminated sheet 11, and winds the blank for the body portion 10a to form a truncated cone. After both side edges are overlapped and the side seam portion 10c is adhered, the peripheral edge portion 10d of the bottom portion 10b is attached to the lower end opening portion so as to overlap the inner side of the body portion 10a, and the upper end opening edge is placed outside. The curled portion 10e is formed by being wound around the substrate.
For bonding the side seam portion 10c between the stretched high-density polyethylene film layer 12 and the low-density polyethylene film layer 16, for example, hot air is used. In the case of ordinary low-density polyethylene film layers, the temperature is 300 to 500 ° C. While it can be bonded, it is necessary to bond at a high temperature of 400 to 450C.
According to such high-temperature hot air bonding, the side seam portion, which is a portion where hot air is applied, and the lower portion of the cup where the bottom and the body are bonded are high-density polyethylene film. Compared with less fogging, it can be finished in a more beautiful cup.

  According to such a paper cup 10, since the stretched high-density polyethylene film layer 12 is used on the outer side surface of the laminated sheet 11, it becomes the same resin as the normal low-density polyethylene film 17 on the inner side surface of the paper cup 10. The side seam portion 10c can be easily bonded in the same manner as before without the need for sky bar treatment or application of an adhesive necessary for bonding different resins.

  Also, since the outer surface side of the paper cup 10 is a stretched high-density polyethylene film 12 printed on the back surface, the surface of the paper cup 10 can be made into a paper cup 10 having gloss of the film itself and having excellent design properties. If it is color printing, the design and decoration can be further improved.

  In the above embodiment, a paper cup has been described as an example of a paper container. However, the present invention is not limited to this, and the present invention can be applied to other paper containers. A gas barrier layer may be provided between them.

  Hereinafter, although the Example which applied the paper container of this invention to the paper cup is described, this invention is not limited to an Example at all.

Example 1
As a laminated sheet, from the outer surface side to the inner surface side, a monoaxially stretched high-density polyethylene film layer, a back surface printed layer, a low-density polyethylene film layer by extrusion lamination, a base paper layer, and a low-density polyethylene film layer by extrusion lamination are used. Prepared.

raw materials,
Uniaxially stretched high-density polyethylene film layer:
Mitsui Hi-Bron Film SMK # 25 (Mitsui Chemicals Fabro Corporation)
Low density polyethylene edge film layer by extrusion lamination:
Petrocene 204 (Tosoh Corporation)
Base paper layer: 270 g / m2 Base paper for paper cup Using these raw materials, backside printing was performed on a uniaxially stretched high-density polyethylene film, and the printed uniaxially stretched high-density polyethylene film and the base paper were 15 μm and 37 μm in tandem laminator. A low density polyethylene film was extruded and laminated to obtain a laminated sheet.

  Using the obtained laminated sheet, 500 paper cups were molded with a normal cup molding machine.

  As a result of measuring the expansion / contraction ratio of the film in the reverse side printing, an elongation of 0.1 to 0.2% occurred in the film feeding direction and an elongation of 0.1% in the width direction. No, 6 colors were printed.

  A side seam (heat seal) is also possible, and a leak test liquid mixed with a surfactant was poured into 500 molded paper cups and left for 20 minutes. There wasn't.

(Example 2)
As the laminated sheet, the same laminated sheet as in Example 1 was prepared except that an adhesive layer with an adhesive for dry lamination was provided instead of the low density polyethylene film by extrusion lamination between the back printed layer and the base paper layer.

  Backside printing is performed on a uniaxially stretched high-density polyethylene film with a thickness of 25 μm, and the printed uniaxially stretched high-density polyethylene film and a base paper that is pre-extruded and laminated with a 37 μm low-density polyethylene film are bonded together with an adhesive for dry laminator. Thus, a laminated sheet was obtained.

  Using the obtained laminated sheet, 500 paper cups were molded with a normal cup molding machine.

  As a result of measuring the stretch rate of the film in the back side printing, the shrinkage of 0.1 to 0.2% was caused in the film feeding direction, and the 0.1% elongation was caused in the width direction. There was no problem and 6 colors were printed.

  A side seam (heat seal) is also possible, and a leak test liquid mixed with a surfactant was poured into 500 molded paper cups and left for 20 minutes. There wasn't.

It is a fragmentary sectional view which expands and shows the part concerning one Embodiment which applied the paper container of this invention to the paper cup.

Explanation of symbols

10 Paper Cup 10a Body 10b Bottom 10c Side Seam 10d Periphery (Bottom)
10e Curled part 11 Laminated sheet 12 Stretched high-density polyethylene film layer 13 Back printed layer 14 Base paper layer 15 Adhesive layer 16 Polyethylene film layer 17 Polyethylene film layer

Claims (4)

A paper container in which a laminated sheet is formed and a seam is adhered,
A stretched high-density polyethylene film layer disposed on the surface; a backside printed layer printed on the backside of the stretched high-density polyethylene film layer; and a base paper layer bonded to the backside printed layer of the stretched high-density polyethylene film layer; A paper container comprising a laminated sheet formed by laminating at least a polyethylene film layer provided on the back surface of the base paper layer, formed into a container shape, and bonded with a seam.   The paper container according to claim 1, wherein the back printed layer is a multicolor printed layer.   The paper container according to claim 1 or 2, wherein the stretched high-density polyethylene film layer has a thickness of 15 to 40 µm. The stretched high-density polyethylene film layer constituting the laminated sheet is composed of a uniaxial high-density polyethylene film, and the stretch rate is 0.25% or less. Paper container.

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