JPH02277635A - Laminated material excellent in aroma retentivity and container using the same - Google Patents

Abstract

PURPOSE:To obtain a laminated material excellent in aroma retentivity by laminating a resin layer wherein polyolefin is compounded with specific copolyester to the surface coming into contact with content of a base material. CONSTITUTION:A laminated material is constituted by laminating a resin layer wherein 5 - 30wt.% of polyolefin is compounded with copolyester formed from terephthalic acid, isophthalic acid and ethylene glycol to the surface coming into contact with content of a base material. The base material is composed of cardboard provided with a polyolefin layer on the outside. A bag like container is formed by providing rules to the aforementioned laminated material and folding the same along the rules to heat-seal the mutual resin layers. By this method, the laminated material reduced not only in the adsorption of the aroma component of content but also in the transfer of the smell of the resin layer to the content and excellent in aroma retentivity can be obtained and a container capable of efficiently preserving component such as juice can be provided.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is characterized in that a resin layer made of a polyester resin whose main component is a copolymerized polyester modified with an acid component is laminated on the side of the base material in contact with the contents. The present invention relates to a laminated material with excellent fragrance retention and a container using this laminated material.

<Prior art> Low-density polyester (
Polyolefin resins such as LD, PE) and polypropylene (PP) are widely used.

This polyolefin resin is harmless to the human body, inexpensive, easy to heat seal, and has excellent water resistance and moisture resistance, and is used by laminating it with a base material via an adhesive layer.

However, when laminating polyolefin resins, the unique odor of polyolefins generated during extrusion processing does not go away, which not only has a significant impact on the taste of liquids and foods, but also has the property of polyolefin resins to easily absorb and permeate aromatic components. As a result, the aroma and taste of the contents were significantly reduced.

In order to solve these problems, it has been proposed to use a copolymerized polyester, which is a resin that generates less odor components and is difficult to adsorb and permeate aroma components, instead of polyolefin resins.

As the copolymerized polyester, a polyester produced by the condensation polymerization of terephthalic acid, isophthalic acid, and ethylene glycol, for example, a polyester produced by the condensation polymerization of a gelcol component containing 1,4-cyclohexane dimetatool and a dibasic acid component. It is.

By using copolymerized polyester, there are fewer substances that occur during heat processing, which polyethylene terephthalate originally has, and by lowering the melting temperature while maintaining low adsorption of aroma components, it is possible to impart heat sealability. It is possible.

However, the above-mentioned copolyester has no mechanical strength, especially no elongation, and becomes brittle against stress applied to the packaging material after heat sealing, making it difficult to form a uniform heat sealing layer. It had the disadvantage of poor heat sealing stability.

In addition, extrusion processability is inferior to that of polyolefin resins, and as a result, it is difficult to form stable films using general extruders for polyolefin resins. It was necessary to take measures such as shortening the time. Low-density polyethylene, ethylene-vinyl acetate copolymer, ionomer, etc. are widely used in the innermost layer of flexible pouches for packaging pharmaceuticals and quasi-drugs containing medicinal ingredients such as poultices and medicated health bath salts. It is used. These resins have excellent heat sealability and also have appropriate mechanical strength.

However, 1-menthol, dl-camphor, and various fragrances, which are medicinal ingredients in poultices and medicated health bath salts, are adsorbed to these resin layers and penetrate further into the adhesive layer with the base material. This has the effect of reducing the adhesive strength and causing the bag to lose its function as a packaging bag. Therefore, packaging bags have been proposed in which the innermost layer is made of polyacrylonitrile resin in order to prevent medicinal ingredients from being adsorbed to and permeating the inner resin layer.

However, polyacrylonitrile resin easily decomposes at high temperatures, requiring careful temperature control and shortening the residence time of the resin, making it difficult to process with a general extrusion machine for polyolefins.

Therefore, it was necessary to make a polyacrylonitrile film on a separate line using a dedicated processing machine, and then attach it to the base material using a method such as dry lamination.

Furthermore, in recent years, containers for beverages such as juices have come to be widely used, which are made of paperboard, provided with ruled lines for processing, and bent from the ruled lines.

In addition, when manufacturing a box-shaped case as a liquid container, there is a process such as punching the container material into the mold of the liquid container and adding groove marks at the bent portions called processing lines, which gives the container material a certain degree of flexibility. Although elongation is required, the above-mentioned copolymer type polyester is insufficient in this respect as well, and there is a risk that cracks may occur or lifting may occur between the paperboard and the paperboard.

<Problems to be Solved by the Invention> An object of the present invention is to provide a laminated material with excellent fragrance retention that is less likely to adsorb aroma components of the contents and less likely to transfer the aroma, etc. of the resin layer to the contents. It was something to do.

Another object of the present invention is to provide a laminated material having excellent fragrance retention and having a resin layer made of a polyester copolymerized with polyolefin and having heat sealability.

Another object is to provide a laminated material with excellent fragrance retention, in which a resin layer made of a copolymerized polyester is formed by extrusion from an extruder, similar to the polyolefin resin on the base material.

Furthermore, an object of the present invention is to provide a container that can efficiently store contents containing aroma components such as juice using the laminated material.

Means for Solving the Problems> The present invention provides terefucuric acid,
It is a laminated material with excellent fragrance retention, which is made by laminating a resin layer containing a copolymerized polyester produced from isophthalic acid and ethyl glycol and a polyolefin blended in a range of 5 to 30% by weight.

Further, the present invention is a laminated material with excellent fragrance retention, in which the base material is a paperboard with a polyolefin layer provided on the outside, and a resin layer similar to that described above is laminated on the side in contact with the contents.

Furthermore, the present invention is a bag-shaped container in which the resin layers of the above-mentioned laminated material are heat-sealed together.

Furthermore, the present invention provides ruled lines on the above-mentioned laminated material,
The container is formed by folding along the ruled lines and heat sealing.

The present invention will be explained in detail below.

The base material that is part of the laminated material of the present invention is not particularly limited, but may include plastics, paper laminates of plastics and metals, laminates of plastics and paper, and laminates of paper and metals. A laminate, a laminate of plastic, paper and metal is preferable, and more specifically a laminate of biaxially oriented polyethylene terephthalate and aluminum foil, a laminate of paper and aluminum foil, a laminate of polyethylene and paper. Examples include laminates, etc., which have excellent heat resistance with little thermal deformation during resin extrusion processing at temperatures of 200°C or higher. Printing may be applied to the less necessary front side of the film or sheet of this base material or to an intermediate layer of the base material.

Next, the polyester resin used for the resin layer laminated on the side of the base material in contact with the contents is a polyester resin that is mainly composed of copolyester modified with an acid component and added with polyolefin. The copolymerized polyester is a polyester produced by condensation polymerization of terephthalic acid, isophthalic acid, and ethylene glycol.

The polyolefins to be added include polyethylene, polypropylene, linear low density polyethylene, and modified products thereof.

By using polyester produced by condensation polymerization of terephthalic acid, isophthalic acid, and ethylene glycol, there is less resin odor caused by volatile components that polyethylene terephthalate resin generally has, and it has low heat adsorption for aromatic components. A trowel is made to obtain polyester that can be sealed. In addition, in order to obtain stable sealing properties during heat sealing and to obtain a resin layer with a uniform thickness distribution during extrusion processing of polyester resin, 5 to 30% by weight
of polyolefin resin must be added.

If the amount of polyolefin added is 30% by weight or more, it is possible to obtain stable sealing properties during heat sealing and extrusion processability close to that of polyolefin, but the resin odor caused by volatile components and the adsorption of aromatic components may occur. The amount increases.

That is, the amount of polyolefin added is 5 to 30% by weight.
Within this range, it is possible to obtain stable sealing performance during heat sealing and extrusion processability very close to that of polyolefin, while suppressing resin odor caused by volatile components and absorption of aromatic components to a satisfactory level. It is.

Methods for laminating a base material and a resin layer made of polyester resin include extrusion lamination using an adhesive, extrusion coating without using an adhesive, extrusion of an adhesive resin and the resin layer in multiple layers using a coextrusion method, There are two methods: extrusion coating on the substrate, and bonding the polyester film prepared in advance to the substrate by dry lamination or the like.

<Function> The resin used for the resin layer described in the present invention has the basic properties of a polyester resin. That is, since less volatile substances are generated than resin, the aroma and taste of the contents are less likely to change due to odor transfer. In addition, since less flavor components of the contents are adsorbed, the aroma and taste of the contents can be retained as they were when filled.

Polyethylene terephthalate, which is generally produced from terephthalic acid and ethylene glycol, has high crystallinity and a high melting point of around 255°, but it is produced by replacing part of the dicarboxylic acid component terephthalic acid with isophthalic acid. Copolymerized polyester has lower crystallinity and a melting point of 2.
00°C or less, and the heat sealability is improved.

However, although such copolymerized polyester resins themselves have heat-sealability with each other, they do not have heat-sealability with polyethylene resin, which is often used for the outermost layer of containers, which is necessary due to the box-making structure of liquid containers. It was insufficient.

Therefore, in the present invention, the above-mentioned copolymerized polyester resin is used as a basic material, and a polyolefin resin having heat-sealing properties is blended in the same manner as or in contrast to the polyolefin resin.

As a result, the innermost resin layer of the present invention has stable heat sealability even at low temperatures around 120°C, similar to polyolefins, and at the same time has sufficient heat sealability for polyolefins such as outermost polyethylene. It has a sexual nature.

In addition, although the copolymerized polyester resin described above has poor elongation and flexibility, by blending it with a polyolefin resin, these physical properties are improved, and the processability of paper containers in which ruled lines are formed and processed is also improved, and the resin layer It is less likely that the paper will crack or become loose compared to the paperboard base material.

<Example 1> Biaxially oriented polyethylene terephthalate film (12μ
) and aluminum foil (9μ) were laminated, and 50% each of terephthalic acid and isophthalic acid were added as dibasic acid components.
Polyester containing mol% and produced by using ethylene glycol as the glycol component,
Density 0.916, melt flow index 23g/
A resin layer (50 μm) made of a polyester resin containing 10 ml of low-density polyethylene was extruded through a two-component reactive urethane adhesive to obtain a laminated material. The amount of low density polyethylene added was 3, 5, 15, and 30.50% by weight based on the total amount of polyester resin.

The resin side made of polyester resin of the obtained laminated material was set as the side that was in contact with the contents, and by heat sealing, a packaging bag having a size of 10cm x 10c+++ and an area of 2000-2000cm was produced in the area in contact with the contents. .

Each bag contains 50ml of 100% orange juice
and 1-menthol 50+ig, respectively, and stored at 25°C. Table 1 shows the heat sealing strength required to make the packaging bag, and the orange adsorbed to the bag after storage for 2 weeks. The amounts of d-limonene and 1-menthol in the juice are shown.

<Comparative Example 1> A polyester resin layer produced on the same base material as in Example 1 by containing 50 mol% each of terephthalic acid and isophthalic acid as the dibasic acid component and using ethylene glycol as the glycol component. (50μ) was extruded through a two-component reactive urethane adhesive. The polyester resin had poor extrusion processability compared to the polyester resin of the polyolefin component used in Example 1, and it was difficult to obtain a polyester resin layer with a uniform thickness. By using a machine, a laminated material similar to that of the present invention was obtained. The obtained laminated material was made into a bag in the same manner as in Example 1, and a storage test was conducted.

The test results are shown in Table 1.

Comparative Example 2> A low-density polyethylene layer (50II) with a density of 0.923 and a melt flow index of 3.7 g/10 sin was extruded on the same base material as in Example 1 via a two-component reactive urethane adhesive. A laminated material of the present invention was obtained. The obtained laminated material was made into a bag in the same manner as in Example 1, and a storage test was conducted. The test results are shown in Table 1.

(Leaving space below) As shown in Table 1, in Comparative Example 1, in which the resin layer in contact with the contents was a copolymerized polyester containing no polyolefin, d-limonene in orange juice and 1-menthol in the poultice were adsorbed. However, the heat sealability is poor.

In addition, Comparative Example 2 in which the layer in contact with the contents is made of polyethylene
Although the heat sealability is excellent, d-limonene, 1-
Menthol was adsorbed inside the packaging bag. On the other hand, in the copolyester resin produced from terephthalic acid or isophthalic acid and ethylene glycol in which the layer in contact with the contents contains polyolefin, which is an example of the present invention, d-IJ monene, 1-menthol It is a laminated material with a good balance of low adsorption and heat sealability.

<Example 2> The following laminated material was obtained in which a resin layer made of polyester resin was laminated on the side in contact with the contents of a base material provided with a polyolefin layer instead of low-density polyethylene on the outside of paperboard.

(1) Paperboard: Milk container paperboard density 310g/Bo (2) Polyolefin resin layer: Low density polyethylene density 0.923g/cj Melt index 3.7g/10m1n Resin thickness 2
0 μ (3) Resin layer: (a) copolymerized polyester resin (b)
Resin blended with polyethylene resin, resin thickness 40μ (a
) Copolymerized polyester resin Copolymerized polyester resin produced using 50 mol% each of terephthalic acid and isophthalic acid as the dicarboxylic acid component and ethylene glycol as the diol component.) Polyethylene resin: Low density polyethylene density
0,916 g/cd melt index 23
g/ca (C) Blending ratio Samples 1 to 5 were obtained by blending polyethylene resin in an amount of 5 to 50% by weight based on the total weight as the innermost resin layer.

The outermost polyolefin resin layer and the innermost resin layer are laminated using a melt extrusion coating method on paperboard.
I did it.

Comparative Example 3> A material for a liquid container was obtained by using only a copolymerized polyester resin without blending the polyethylene resin in the innermost layer (3) in the structure of Example 1. The resin thickness was the same as 40μ.

<Comparative Example-4> In the structure of Example-2, the same low-density polyethylene as the olefin resin of the outermost layer was used for the innermost resin layer to obtain a material for a liquid container. The resin thickness was kept the same at 40 μm.

Note that this structure is almost the same as that of general liquid container materials for milk, juice, and the like.

<Example-3> Samples 1 to 5 of liquid container materials obtained in Example-2
Performance evaluation was performed on the following items for the samples obtained in Comparative Example-3 and Comparative Example-4.

(1) Absorption of flavor components ■ Prototype liquid containers using each sample (with a content capacity of 100 d); ■ Fill each container with 1000 d of 100% orange juice, and store in a sealed container at 5'C for 4 weeks. After storage, limonene in the orange juice adsorbed on the innermost resin of the liquid container was quantitatively measured using gas chromatography.

(2) The amount of limonene adsorbed in the innermost layer low-density polyethylene composition of Comparative Example-2 was assumed to be 100%, and the adsorption amount of each sample was displayed.

(2) Heat sealability between innermost resin layers Layer each sample between the innermost resin layers, heat seal, and check heat sealability Use bar sealer Temperature: 130°C to 220'C Pressure: 3kg/d Time: 5 seconds ( 3) Heat sealability of the innermost resin layer and the outermost polyolefin layer Each sample was layered with the innermost resin layer and the outermost polyethylene resin layer and heat sealed, and the heat sealing conditions were the same as in (2).

(4) Ruled line bending test After repeating the bending and stretching test up to 90° of the ruled line portion 20 times using a ruled line strength tester (■ manufactured by Resca), cracks in the ruled line portion were evaluated. The bending speed during the test was 10 degrees/second.

Table 2 shows the performance evaluation of each sample (11 to (4) above).

(Margins below) The heat sealability of the sample with the REN configuration was good, as the innermost layers and both the innermost layer and the outermost layer were heat-sealed stably from a low sealing temperature, but the adsorption amount of limonene in orange juice was large; Sensory tests also revealed that there was an odor such as a polyethylene odor.

In addition, limonene was not detected in the sample with the innermost layer copolymerized polyester composition of Comparative Example 3, and it is thought that it is not adsorbed at all. According to sensory tests, there was no off-odor, and the taste and aroma did not change. However, the heat sealability was poor. In particular, the innermost layer copolyester showed almost no heat sealability compared to the outermost layer polyethylene resin.

On the other hand, in the innermost layer of Example 2, which had a copolyester composition containing polyethylene, limonene was not detected or was at an extremely low level compared to Comparative Example 3, and sensory tests showed that there was no off-odor or strange taste. There wasn't.

In particular, sample 2 with a boleethylene blending ratio of 5 to 30%
4 has a temperature range in which limonene is not detected and the heat sealability is good between the innermost layers and between the innermost layer and the outermost layer, and in practice, sufficient heat sealability can be obtained by increasing the heat sealing conditions. I was able to do it.

In addition, regarding cracks in the ruled line part when folding, Example 2
Similar to Comparative Example 4, this was not observed in Samples 2 to 5.

<Effects of the Invention> (1) By using the laminated material of the present invention, it is possible to obtain a container in which the medicinal components and flavor components of the contents are less likely to be absorbed by the container (and there is less migration of odors, etc. from the container). As a result, the taste and aroma of the contents, such as alcoholic beverages and juices, which contain many flavor components and are sensitive to odor components transferred from the outside, can be preserved as they were when filled. becomes possible.

(2) The laminated material of the present invention has the effect of (1) above, and has good heat sealability, box forming processability, etc. as well as the conventional innermost layer polyolefin resin composition, so it is easy to use box forming machines and contents. Conventional methods such as filling can be used to obtain the required product properties.

(3) Furthermore, when forming a resin layer on the base material, it can be extruded using a commonly used extruder for polyolefins.

Special Person asking for permission Toppan Printing Co., Ltd. Representative: Kazuo Suzuki

Claims (4)

[Claims] (1) Excellent fragrance retention with a resin layer laminated on the side of the base material that comes into contact with the contents, which is made of a copolymerized polyester produced from terephthalic acid, isophthalic acid, and ethylene glycol mixed with polyolefin in a range of 5 to 30% by weight. Laminated material. (2) The laminated material with excellent fragrance retention according to claim (1), wherein the base material is a paperboard provided with a polyolefin layer on the outside. (3) A bag-shaped container in which the resin layers of the laminated material according to claim (1) are heat-sealed together. (4) A container formed by providing the laminated material of claim (2) with ruled lines, bending from the ruled lines, and heat sealing.