JPH08337237A - Paper container for liquid - Google Patents

Abstract

PURPOSE: To provide a paper container wherein as a barrier layer, a barrier base material which is excellent in a molded shape and free from generation of pin holes is used at the time of molding. CONSTITUTION: In manufacturing a paper container for liquid, polyethylene resin fabricated by using a metallocene catalyst is first made into a film by means of inflation or the like to manufacture a polyethylene film 17. Then polyethylene layers 11, 13 are laminated on a surface and a rear of a cardboard to be a base material layer 12 by extrusion-lamination method, and separately, the above mentioned polyethylene film 17 is laminated on a polyethylene terephthalate film 16 with a silicon oxide vapor-deposited film 15 applied by dry lamination method using urethane adhesive agent. A laminated material 10 thus manufactural is used to make a parallelopiped paper container for liquid having a gabled summit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid paper container in which a peripheral wall is formed by using a laminated material having a paperboard as a base material, a metal foil, a film on which an inorganic compound vapor-deposited thin film is formed, and a barrier plastic film as a barrier layer. In particular, the present invention relates to a liquid paper container having an innermost layer excellent in mechanical suitability such as moldability and filling property.

[0002]

2. Description of the Related Art A liquid paper container having a peripheral wall formed by using a laminate material having a barrier layer made of a paperboard as an aluminum foil, an inorganic compound vapor-deposited thin film, or a barrier plastic film is used as a liquid paper container. Liquid paper containers of various forms, such as a roof-shaped square tubular container (Fig. 2), a cylindrical container (Fig. 3), a tapered paper cup-shaped container (Fig. 4), or a brick container with a flat top. It is in circulation. And, for example, when the barrier layer is a film formed with an inorganic compound vapor-deposited thin film, [outside the container] polyethylene layer / paperboard layer / polyethylene layer / polyethylene layer / polyethylene terephthalate layer / silicon oxide vapor-deposited thin film layer / A polyethylene layer [inside the container] is used, and the polyethylene resin used for the innermost polyethylene layer is a high-pressure polyethylene obtained by polymerizing ethylene gas under a high pressure of 1000 atm or higher, or A resin called low density polyethylene was common.

However, in the liquid paper container of this structure, the innermost low density polyethylene layer is heated and melted,
When molding a laminated material having a barrier layer when molding into a container, pin holes may be generated in the polyethylene layer when heat energy is applied to melt the polyethylene layer. In particular, when aluminum foil is not used for the barrier layer, the thermal conductivity is poor, so when sufficient heat energy to melt the polyethylene layer is applied, pinholes often occur in the polyethylene layer, conversely squeezing the heat. However, it is very difficult to determine the setting conditions from the side of the filling molding machine, where sufficient sealing (molding) is not possible, pinholes do not occur, and there are no seal defects. Even if the conditions were decided, the permissible range of the aptitude condition was very narrow. On the other hand, if only the sealing suitability is considered, ionomer resin, ethylene / vinyl acetate copolymer resin, etc. have been studied instead of the innermost polyethylene layer, but the effect of the unique resin odor on the contents However, when the contents are large and the contents of food and aroma components are important, it was difficult to use from the sensory aspect.

[0004]

DISCLOSURE OF THE INVENTION The present invention is directed to a film having a paperboard as a base material, a metal foil and an inorganic compound vapor-deposited thin film,
Alternatively, a barrier plastic film is used as a barrier layer, and the innermost layer resin is a high-pressure polyethylene resin. A laminated material is used to eliminate the above-mentioned problems related to a liquid paper container that forms a peripheral wall. ,
An object of the present invention is to provide a liquid paper container having an excellent moldability of the container and using a barrier layer which does not generate pinholes during molding.

[0005]

In order to achieve the above-mentioned object, the present invention is a laminated material comprising a paperboard as a base material and a metal foil, a film on which an inorganic compound vapor-deposited thin film is formed, or a barrier plastic film as a barrier layer. A liquid paper container in which a peripheral wall is formed by using a polyethylene resin layer produced by using a metallocene catalyst as the innermost resin layer of the laminated material is provided.

The metallocene catalyst is called a Kaminsky catalyst, which is a combination of zirconocene dichloride and methylalumoxane, and is characterized by high polymerization activity for ethylene and uniform active sites. The polyethylene resin obtained by polymerizing ethylene using this metallocene catalyst has a low temperature sealability, a low heat seal start temperature, and a wide suitable seal temperature range, as compared with a polyethylene resin produced by a conventional high pressure method. It has features such as transparency, toughness, and excellent mechanical properties.

The metal foil is typically an aluminum foil, and the inorganic compound forming the vapor-deposited thin film is composed of silicon oxide, aluminum oxide, magnesium oxide alone or a mixture thereof. Further, the barrier plastic is a film made of polyvinylidene chloride, ethylene-vinyl alcohol, or a film coated with these resins.

[0008]

As described above, according to the present invention, since the polyethylene resin produced by using the metallocene catalyst is used for the innermost resin layer of the laminated material, it is possible to seal at a lower temperature and a wider temperature range than before. Molding) is possible. Further, at the time of molding and sealing the top portion and the bottom portion, the molding can be performed without applying an excessive amount of heat such as hot air, so that pin holes and the like at the top portion and the bottom portion due to overheating are not generated.

[0009]

The present invention will be described in detail with reference to the following examples.
First, a polyethylene resin produced using a metallocene catalyst was formed into a film by a method such as an inflation method to produce a polyethylene film having a thickness of 60 μm.
Next, a laminated material for producing a liquid paper container was produced. That is, a polyethylene layer having a thickness of 20 μm and a polyethylene layer having a thickness of 25 μm were laminated on the front and back sides of a paperboard having a basis weight of 320 g / m ² as a base material layer by an extrusion lamination method. Separately, a 12μ film with a 400Å thick silicon oxide vapor deposition thin film was applied.
On the polyethylene terephthalate surface of the m-thick polyethylene terephthalate film, the polyethylene film produced using the above-mentioned 60 μm-thick metallocene catalyst was laminated by a dry lamination method using a urethane adhesive. A 25 μm thick polyethylene layer of the above-mentioned polyethylene layer / paperboard layer / polyethylene layer laminated material and a silicon oxide vapor deposited thin film layer / polyethylene terephthalate layer / silicon oxide vapor deposited thin film of a polyethylene layer laminated material produced using a metallocene catalyst. The layer surface and the polyethylene layer having a thickness of 30 μm are attached by an extrusion lamination method, and the polyethylene layer (11) / 320 g / m ² paperboard layer (12) having a thickness of 20 μm of the present embodiment shown in FIG.
/ 25 μm thick polyethylene layer (13) / 30 μm thick polyethylene layer (14) / 400 Å thick silicon oxide deposited thin film layer (15) / 12 μm thick polyethylene terephthalate layer (16) / 60 μm thick polyethylene layer produced using a metallocene catalyst (17) ) A laminated material (10) for a liquid paper container having [inside the container] configuration was prepared.

Next, the laminated material (10) thus prepared was used to prepare a rectangular tubular liquid paper container (20) having a gable roof top shown in FIG. That is, the produced laminated material (10) was punched with an ordinary punching machine to produce a blank plate of a liquid paper container, and the blank plate was side-sealed with a sucking machine to produce a sleeve.

This sleeve is loaded into a filling molding machine which employs a hot air type heat source, and the outer diameter is 70 mm × 7.
A liquid paper container having a capacity of 500 mm and a height of 0 mm and a height of 140 mm was prepared. At that time, the top molding part (2
1) and the heater temperature of the bottom molding part (22) are set to 270 to 270.
By changing the temperature up to 340 ° C. at every 10 ° C., the temperature conditions at which the container can be formed were obtained. Table 1 shows the evaluation results.

<Comparative Example 1> Separately from this, in order to perform comparative evaluation with the liquid paper container of the present embodiment, a 20 μm thick polyethylene layer (51) / 3 of [container outside] of the conventional structure shown in FIG. 5 was used.
20 g / m ² paperboard layer (52) / 25 μm thick polyethylene layer (53) / 30 μm thick polyethylene layer (54) / 40
A 0 Å thick silicon oxide vapor-deposited thin film layer (55) / 12 μm thick polyethylene terephthalate layer (56) / 60 μm thick polyethylene layer (57) [inside the container] A laminated material (50) for a liquid paper container having the same structure as in the example It was made. In addition, the innermost polyethylene layer is a low density polyethylene resin manufactured by a high pressure method, which is an inflation grade Mirason 401P manufactured by Mitsui Petrochemical Co., Ltd.
It was used.

A sleeve was produced from this laminated material (50) in the same manner as in the example, and this sleeve was loaded into a filling molding machine employing a hot air type heat source as in the example, and the outer diameter was changed. 70mm × 70mm, height 140mm
A liquid paper container having a capacity of 500 milliliters was manufactured.
At that time, the heater temperature of the top molding part and the bottom molding part was changed from 270 to 340 ° C. at every 10 ° C., and the temperature conditions at which the container could be molded were obtained. Table 1 shows the evaluation results.

[0014]

[Table 1]

From the results shown in Table 1, a liquid paper container (Example) using a laminated material using polyethylene produced by using a metallocene catalyst for the innermost layer is a liquid using polyethylene produced by a high pressure method for the innermost layer. It was found that, compared with the paper container (Comparative Example 1), the moldable temperature was lower in both the top molding portion and the bottom molding portion, and the suitable sealing temperature range was widened.

[0016]

As described above, according to the present invention, the molding seal can be carried out at a lower temperature than the conventional one, and the temperature range suitable for sealing is widened. Therefore, it is easy to determine the condition of the molding seal of the paper container molding filling machine. Therefore, the productivity of the molding and filling machine is improved. Further, also in a laminated material using an aluminum foil as a barrier layer, the temperature range suitable for sealing is widened and the productivity of the molding and filling machine is improved. Furthermore, since polyethylene produced using a metallocene catalyst has a uniform molecular weight distribution, the influence of resin odor when filling beverages or contents in which aroma components are important is reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one structural example of a laminated material of a liquid paper container of the present invention.

FIG. 2 is a perspective view showing an embodiment of a liquid paper container assembled using the same laminated material.

FIG. 3 is a perspective view showing an embodiment of another liquid paper container.

FIG. 4 is a perspective view showing another embodiment of the liquid paper container.

FIG. 5 is a cross-sectional view showing one structural example of a laminated material of a conventional liquid paper container.

[Explanation of symbols]

10 ... Laminating material 11 ... Polyethylene layer 12 ... Paperboard layer 13 ... Polyethylene layer 14 ... Polyethylene layer 15 ... Silicon oxide vapor deposition thin film layer 16 ... Polyethylene terephthalate layer 17 ... Polyethylene produced using metallocene catalyst Layer 20 ... Liquid paper container 21 ... Top molding part 22 ... Bottom molding part 50 ... Laminating material 51 ... Polyethylene layer 52 ... Paperboard layer 53 ... Polyethylene layer 54 ... Polyethylene layer 55 ... Silicon oxide vapor deposition Thin film layer 56 ... polyethylene terephthalate layer 57 ... polyethylene layer

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[Procedure amendment]

[Submission date] November 17, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014]

[Table 1]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideki Yamamoto 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd.

Claims (1)

[Claims] 1. A liquid paper container in which a peripheral wall is formed by using a laminated material having a paperboard as a base material and a metal foil, a film on which an inorganic compound vapor-deposited thin film is formed, or a barrier plastic film as a barrier layer. A liquid paper container characterized in that a polyethylene resin layer produced by using a metallocene catalyst is used as the innermost resin layer.