JPH05208472A - Liquid container comprising paper as main body - Google Patents

Abstract

(57) [Abstract] [Purpose] A container for liquids, which is composed mainly of paper and has a sleeve-shaped laminated material formed by providing plastic layers on the inner and outer surfaces, and one end is folded inside and heat-sealed to form the bottom. It is an object of the present invention to provide a container having a bottom portion which is less likely to be adsorbed by the fragrance component contained in the contents and which is easily heat-sealed with a strong adhesive force. [Constitution] A liquid container using a laminated material mainly composed of paper and provided with a plastic layer on the inner and outer surfaces, wherein the inner surface of the laminated material is terephthalic acid, and the inner surface and the outer surface are heat-bonded when the container is formed. It consists of a resin in which 5 to 30% by weight of a copolymer of ethylene and an unsaturated carboxylic acid or a (meth) acrylic acid ester is mixed with a polyester having isophthalic acid and ethylene glycol as a monomer, and the outer surface of the laminated material is unsaturated with ethylene. It is characterized by comprising a resin in which an olefin is mixed in an amount of 0 to 90% by weight in a copolymer with carboxylic acid or (meth) acrylic acid ester.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid container mainly composed of paper. More specifically, the present invention relates to a liquid container mainly containing paper which can store liquid contents such as juice and can be stored for a long period of time without reducing the perfume components contained in the contents.

[0002]

2. Description of the Related Art Liquid containers mainly composed of paper are well known and widely used as containers for storing milk, juice, liquor and the like.

This container is manufactured, for example, from a blank as shown in FIG. 2 through the steps as shown in FIGS. 3 and 4.

That is, the blanks 1 are provided with plastic layers on both sides of the paper to prevent the liquid container from leaking, and at the folded portion, the inner surface and the outer surface can be heat-bonded.

The blank 1 has a shape as shown in FIG. 2, for example.
12, 14 are connected to each other via a bending line. Below each of the side wall pieces 11, 12, 13, and 14, a bottom portion forming piece is continuously provided via bending lines 11a, 12a, 13a, and 14a, and above the bending line 11b,
Top forming pieces are continuously provided via 12b, 13b, and 14b. Further, a glue margin 15 for connecting the side wall pieces 11, 12, 13, 14 to form the blank 1 into a sleeve is provided.

The side wall pieces 11 and 13 face each other when the blank is formed on the sleeve, and the side wall forming pieces 11 and 13 also face each other when formed on the sleeve. The bottom forming pieces 111 and 131 provided below the side wall pieces 11 and 13 facing each other have substantially the same shape, and the top forming pieces provided above the bottom forming pieces 111 and 131 are also similar. The bottom forming piece and the top forming piece provided on the side wall pieces 12 and 14 have the same shape.

Bottom forming piece 1 provided on the side wall piece 11.
As shown in the figure, 11 is a rectangular shape with two corners removed,
Its length is slightly longer than 1/2 of the width of the sidewall piece 12.

The bottom forming piece provided on the side wall piece 12 is divided into three pieces 121, 122, 123 via two bending lines 12c and 12d. Folding line 1
2c and the bending line 12d are for facilitating the folding of the bottom forming piece. The length of the bottom portion forming piece provided on the side wall piece 12 is substantially equal to 1/2 of the width of the side wall piece 11.

The side wall piece 13 is provided with a bottom portion forming piece 131 similar to the side wall piece 11. In the illustrated example, the bottom forming piece 11 has a rectangular shape in which only one corner is cut off.
Although it is different from 1, it may be a rectangle obtained by scraping two pieces.

The side wall piece 14 is provided with a bottom portion forming piece similar to the side wall piece 12. In addition, the top forming piece provided on the side wall piece 11 is composed of four pieces 1 through the bending line.
It is divided into 12,113,114,115. The folding line is for facilitating the folding of the top forming piece. The top forming piece of the side wall piece 12 is divided into two pieces 124 and 125 via a fold line. The top forming piece provided on the side wall piece 13 and the top forming piece provided on the side wall piece 11 are the same, and the top forming piece and the side wall piece 12 provided on the side wall piece 14 are provided. The same applies to the top forming piece.

The blank 1 is, as shown in FIG.
A cylindrical rounding margin 15 is heat-bonded to the inside of the side wall piece 11 to form a sleeve.

The method of forming the bottom of the container from this sleeve is shown in FIG. First, hot air is blown onto the inner and outer surfaces of one end of the sleeve to soften the plastic on the inner and outer surfaces of the sleeve.

Next, while folding the folding lines 12c and 12d in a valley fold, the folding line 12a is folded in a mountain fold and the bottom forming pieces 121, 122, 123 are folded inward of the sleeve. At the same time, since the length of the bottom forming piece is approximately ½ of the width of the side wall piece 11 in the same manner, both bottom forming pieces do not overlap each other by folding and the bottom of the sleeve is closed.

Then, the bottom forming piece 111 is folded in,
Bottom forming pieces 121, 122, 123 and 141, 14
2, 143, and the bottom forming piece 111 is placed on the bottom forming pieces 121, 122, 123 and 141, 142, 1
Heat bond on 43. Further, the bottom portion forming piece 131 is folded on the bottom portion forming piece 111. Bottom forming piece 111
Since both of the bottom forming piece 131 and the bottom forming piece 131 are longer than ½ of the width of the side wall forming piece 12, when they are folded, the bottom forming pieces 111 and 131 overlap with each other at their tip ends. The overlapping portions are heat-bonded to each other to prevent liquid leakage and form a bottom portion.

The top portion is formed into a gable shape by folding a top portion forming piece and thermally adhering it. By the way, for the blank, conventionally, a laminated material in which a polyolefin resin such as polyethylene is provided on both surfaces of paper is used from the viewpoint of hygiene and the like. However, the polyolefin provided on the inner surface of the container easily adsorbs the fragrance component contained in juice or the like, and the flavor changes due to long-term storage.Therefore, the use of polyester, which is easily heat-adhesive as a plastic, has been proposed as an alternative plastic. There is. That is, it is a polyester having terephthalic acid, isophthalic acid and ethylene glycol as monomers.

Conventionally, the polyester is used for the inner surface of the container and a simple substance of polyolefin such as polyethylene is used for the outer surface of the container. Therefore, when the container is formed from blanks, the inner surface and the outer surface are heat-sealed. Had insufficient adhesive strength. Furthermore, in detail, in order to form the bottom of the container, it is necessary to heat-bond the inner surface of the bottom forming piece 131 to the outer surface of the bottom forming piece 111.
Since the outer surface of the bottom-forming piece 111 is made of polyolefin and the inner surface of the bottom-forming piece 131 is made of heat-adhesive polyester, it is not easy to heat-bond them together. However, there is a problem that liquid leakage of the contents occurs.

[0017]

Therefore, in the present invention, a polyester which is less likely to adsorb a fragrance component contained in the contents such as juice, and which does not change its flavor even after long-term storage and which is easily heat-bonded is used for the inner surface of the container. However, it is an object of the present invention to provide a liquid container in which the liquid of the contents does not leak by being peeled off by dropping the container or the like.

[0018]

In order to solve this problem, the present invention is a liquid container using a laminated material mainly composed of paper and provided with a plastic layer on the inner and outer surfaces thereof. In a container in which the outer surface and the outer surface are heat-bonded, the inner surface of the laminated material is a polyester containing terephthalic acid, isophthalic acid and ethylene glycol as a monomer, and a copolymer of ethylene and an unsaturated carboxylic acid or a (meth) acrylic acid ester Consisting of 30% by weight of mixed resin,
A liquid container mainly composed of paper, characterized in that the outer surface of the laminated material is made of a resin obtained by mixing 0 to 90% by weight of an olefin with a copolymer of ethylene and an unsaturated carboxylic acid or (meth) acrylic acid ester. Is provided.

[0019]

DETAILED DESCRIPTION The liquid container of the present invention will be described in detail with reference to the drawings shown as an example. The container according to the invention is formed from a blank 1 made of laminated material. This laminated material is a resin in which the inner surface of the container is a polyester obtained by mixing 5 to 30% by weight of a copolymer of ester and unsaturated carboxylic acid or (meth) acrylic acid ester with polyester having terephthalic acid, isophthalic acid and ethylene glycol as monomers. The outer surface of the container is made of a resin in which 0 to 90% by weight of an olefin is mixed with a copolymer of ethylene and an unsaturated carboxylic acid or a (meth) acrylic acid ester. An example of a specific layer structure is shown in FIG.

That is, in FIG. 1, the outer surface layer is 1
It is a resin obtained by mixing 0 to 90% by weight of an olefin with a copolymer of ethylene and an unsaturated carboxylic acid or a (meth) acrylic acid ester.

Examples of the (meth) acrylic acid ester include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, glycidyl acrylate, methacryl. Examples thereof include glycidyl acid, and examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, and maleic anhydride. Examples of the olefin include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene and the like.

As long as the ethylene-based copolymer contains ethylene and a (meth) acrylic acid ester or an unsaturated carboxylic acid as an essential component, the copolymer contains a (meth) acrylic acid ester or an unsaturated carboxylic acid. Alternatively, it may be a ternary or multi-component copolymer containing other copolymer components.

As the other copolymerization component, an unsaturated carboxylic acid or its anhydride, or a monomer such as (meth) acrylic acid ester can be used. The (meth) acrylic acid may be partially metallized.

Therefore, the ethylene-based copolymer used in the present invention is particularly preferably ethylene / (meth) acrylic acid ester copolymer, ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid ester. / (Meth) acrylic acid terpolymer or an ionomer resin in which a part of the (meth) acrylic acid component in the terpolymer is metal chloride. Further, when the ionomer resin in which the (meth) acrylic acid component is metal chloride is used, the metal is preferably sodium, magnesium, calcium, zinc or the like.

Such an ethylene-based copolymer is 190
Melt float rate at 2160 g at 0.0
It is preferably 5 to 100 g / 10 minutes, particularly 0.5 to 50 g / minute. This is because if the melt flow rate is less than 0.05 g, the viscosity is too high to increase the molding rate, and if the melt flow rate is more than 100 g, the viscosity is too low to form a uniform film. Other ethylene copolymers, olefins, viscosity imparting agents, various additives and the like may be blended in this resin layer.

The mixing amount of the olefin is 0 to 90% by weight based on the ethylene copolymer. If it exceeds 90% by weight, strong adhesion to the inner surface is difficult. 0 to this
In the range of 90% by weight, thermal adhesion to the inner surface is easy and strong peel strength is obtained. Generally, practical peel strength is 90
The degree of peeling is 0.5 Kgf / 15 mm or more when measured at a peeling speed of 300 mm / min. In this case, the peel strength of the paper exceeds the interlaminar strength of the paper, so that the paper peels. Also, 1.
It is practical that the number of drops from 2 m is approximately 5 or more.

This resin layer 1b is laminated on 1a. Although it is possible to bond the paper 1a and the resin layer 1b to each other with an adhesive, it is preferable to laminate them by heat bonding. Thermal bonding can be performed by a method (extruder coating method) in which the resin layer is pressed against the paper substrate 1a while being melt-extruded. In addition, the resin layer 1b of the portion forming the bottom portion
Is preferably oxidized by corona discharge treatment or the like.

In FIG. 1, the layer on the inner surface is indicated by 1d, which is a mixture of polyester and ethylene copolymer. This polyester contains isophthalic acid as a monomer component in addition to terephthalic acid and ethylene glycol. This is because it is difficult to heat bond polyester containing no isophthalic acid component. Further, the ethylene-based copolymer makes the heat adhesion with the resin layer 1b of the outer layer easier and stronger at the bottom of the container, and the above-mentioned ethylene-based copolymer can be used as the ethylene-based copolymer.

The mixing amount is 5 to 30% by weight of the ethylene copolymer with respect to the polyester. If it is less than 5% by weight, thermal adhesion is not easy and strong adhesion is also difficult. Also,
If it exceeds 30% by weight, the adsorbed amount of the fragrance component increases, and it becomes difficult to store the liquid containing the fragrance component such as juice for a long time while maintaining the flavor. On the other hand, in the range of 5 to 30% by weight, the adsorption of the fragrance is small and the thermal bonding is easy. Generally, the adsorbed amount of d-limonene after 14 days is
It is considered that a practical adsorption amount is 5% or less.

The inner surface layer 1d can be directly laminated on the paper substrate 1a, but as shown in the drawing, the adhesive layer 1c is formed.
It is preferable to stack the layers via. The above-mentioned ethylene copolymer can be used for the adhesive layer.

The adhesive layer 1c and the mixture layer 1d on the inner surface are
The paper substrate 1a can be laminated on the substrate 1a by sequentially performing extruder coating. The resin layer 1b on the outer surface is 10 to 100 μm, the adhesive layer 1c is 5 to 50 μm,
The mixture layer 1d on the inner surface may be formed to a thickness of about 10 to 100 μm. The method of forming the blank 1 on the sleeve is the same as the conventional method. The method of forming the bottom of the container from the sleeve may be the same as the conventional method, but hot air is blown to the inner and outer surfaces of the bottom to form the resin layer 1b on the outer surface and the mixture layer 1d on the inner surface prior to forming the bottom. Need to be softened.

[0032]

EXAMPLES The present invention will be described below with reference to examples. As blanks, those shown in the sectional view of FIG. 1 and the plan view of FIG. 2 were used. Each layer is composed of ethylene / methacrylic acid / ethyl methacrylate terpolymer with polyethylene
Resin (thickness 20 μm) mixed with 0 wt%, paper (basis weight 31
5 g / m ² ), ethylene / methacrylic acid copolymer (thickness 20 μm), terephthalic acid, and a mixture of isophthalic acid and polyester having ethylene glycol as a monomer, and 20% by weight of ethylene / methacrylic acid copolymer (thickness). 20 μm).

The laminate was prepared by first forming an ethylene / methacrylic acid / ethyl methacrylate terpolymer on a paper substrate,
The resin mixed with 20% by weight of polyethylene was extruded, and the opposite surface was coated with ethylene /
A methacrylic acid copolymer and a mixture were produced by extruder coating, and a resin layer obtained by mixing 20% by weight of polyethylene with an ethylene / methacrylic acid / ethyl methacrylate terpolymer on the outer surface was subjected to corona discharge treatment,
Blanks 1 were manufactured by punching and stamping the blanks. Further, blanks were prepared by changing the weight% of polyethylene in the resin layer on the outer surface and the weight% of ethylene / methacrylic acid copolymer mixed in the mixture on the inner surface in the preparation of the blank 1 above, and Examples and Comparative Examples were prepared. And

Using this blank, a container bottom was formed by the method shown in FIGS. Prior to the formation, the inner surface and the outer surface of the bottom were blown with hot air at 350 ° C. for 1.5 seconds to soften them.

The peel strength of the portion where the inner surface of the bottom-forming piece 131 is heat-bonded to the outer surface of the bottom-forming piece 111 at the bottom was measured at 90 ° peeling at a peeling speed of 300 mm / min.

In addition, the carton formed by adding water to 1.
It was dropped from a height of 2 m, and the number of times until the bag was broken was measured. Subsequently, using only the mixture layer, it was cut into 20 × 40 mm, dipped in d-limonene, and after a certain period of time, d-
The amount of limonene adsorbed was measured. The adsorption amount is the weight after a certain period of time divided by the weight before immersion.

The peel strength, the drop strength, and the adsorption amount are shown in Table 1
>. The unit of peel strength is "kgf / 15m
m ”, the unit of drop strength is the number of times, and the unit of adsorption amount is“% ”.

[0038]

[Table 1]

[0039]

As described above, according to the present invention, a resin obtained by mixing 0 to 90% by weight of an olefin with a copolymer of ethylene and an unsaturated carboxylic acid or a (meth) acrylic acid ester is used on the outer surface. Use terephthalic acid on the inner surface,
Since polyester containing isophthalic acid and ethylene glycol as a monomer is mixed with ethylene and unsaturated carboxylic acid or (meth) acrylic acid ester copolymer in an amount of 5 to 30% by weight, it can be stored for a long time while maintaining the flavor. Thus, it is possible to obtain a liquid container having excellent drop strength.

[0040]

[Brief description of drawings]

FIG. 1 is a sectional view of a laminated material showing an embodiment of the present invention.

FIG. 2 is a plan view of a blank showing a conventional technique.

FIG. 3 is a perspective view of a sleeve showing a conventional technique.

FIG. 4 is an explanatory view of a bottom portion forming process showing a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Laminated material 1a ... Paper base 1b ... Resin layer 1c ... Adhesive layer 1d ... Mixture layer

Claims (1)

[Claims] 1. A liquid container using a laminated material mainly composed of paper and provided with a plastic layer on the inner and outer surfaces thereof, wherein the inner surface of the laminated material is terephthalate in a container in which the inner surface and the outer surface are heat-bonded when the container is formed. It is made of a resin in which 5 to 30% by weight of a copolymer of ethylene and an unsaturated carboxylic acid or a (meth) acrylic acid ester is mixed with a polyester having acid, isophthalic acid and ethylene glycol as a monomer, and the outer surface of the laminated material is made of ethylene. A liquid container mainly composed of a paper, comprising a resin in which an olefin is mixed in an amount of 0 to 90% by weight with a copolymer of an unsaturated carboxylic acid or a (meth) acrylic acid ester.