JPH06206289A - Packaging material - Google Patents

Abstract

PURPOSE:To reduce adsorption and sorption of perfume ingredient, effective ingredient, etc., eliminate eluation of low molecular weight ingredient, various additives to a content, to further provide excellent impact resistance, eliminate whitening even in the case of heat treating and taste malfunction in food content even by heat treating. CONSTITUTION:A polyester resin layer which contains 1,4-butane diol as glycol ingredient of main ingredient and at least 10 mole % of sebacic acid is provided at a side of a base material film made of at least one layer of film or sheet in contact with a content.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material for foods or pharmaceuticals, and more particularly to a packaging material composed of a composite film using a heat-adhesive polyester resin.

[0002]

2. Description of the Related Art Conventionally, as a heat-adhesive resin for a composite film used as a packaging material, a polyolefin resin such as polyethylene or polypropylene can be mentioned as a typical one.

However, in the case of a packaging material using such a polyolefin-based heat-adhesive resin, adsorption or sorption of its scent component when the content is, for example, juice, or its active ingredient when it is a happen or the like. It is large and moreover, a large amount of low-molecular-weight components such as olefin odors are eluted, which causes a drawback such as a change in taste and an offensive odor. Further, when polypropylene is used as the polyolefin, it is inevitable to use an antioxidant in order to prevent oxidative deterioration of the polypropylene. Therefore, for example, when used in food packaging, the above-mentioned antioxidant is eluted and migrates to the contents such as foods. That was also a problem.

For this reason, a polyester-based heat-adhesive resin which does not have the above-mentioned drawbacks has recently been used as a heat-adhesive resin for packaging materials for foods and pharmaceuticals.

[0005]

However, when the above polyester-based heat-adhesive resin is used, the drawbacks of the polyolefin-based resin are certainly improved, but
Such a packaging material is inferior in flexibility due to the properties of the polyester resin itself, and particularly when subjected to heat treatment such as retort sterilization and boiling sterilization, crystallization of the polyester resin is promoted and becomes brittle. However, it has a drawback in that it has insufficient impact resistance and can be applied only to light packaging.

Japanese Unexamined Patent Publication (Kokai) No. 1-182255 discloses a packaging material using a polybutylene terephthalate resin film. However, such a packaging material has a problem of being whitened and impaired in appearance when subjected to retort treatment. The heat sealability is also inferior.

In view of the above problems, the present applicants have filed a patent application No. 3-
In the specification of 122712, a method of using a polyester resin containing an aliphatic dicarboxylic acid mainly composed of adipic acid in a specific amount or more is proposed.

[0008] However, although the above drawbacks have been improved by such a technique, when such a resin is used, the food, which is the content, has a bad taste by being subjected to heat treatment such as retort sterilization. There was the problem of occurring.

Therefore, the present invention has been made in view of the above problems, and its object is to reduce adsorption and sorption of scent components, active ingredients, etc., without elution of low molecular weight components and various additives into the contents. It is another object of the present invention to provide a packaging material which is excellent in impact resistance, does not cause whitening even when subjected to heat treatment, and does not cause a bad taste in the contents such as food even when subjected to heat treatment.

[0010]

In order to achieve the above object, the packaging material of the present invention comprises a 1,4-glycol component as a glycol component on the side of the base film consisting of at least one layer of film or sheet which is in contact with the contents. A polyester-based resin layer containing butanediol as a main component and sebacic acid as an acid component in an amount of at least 10 mol% is provided.

The polyester resin containing sebacic acid as the above acid component is hereinafter referred to as "polyester resin of the present invention".

The present invention will be described in more detail below.

The polyester resin of the present invention contains at least 10 mol% of sebacic acid as an acid component, and has 1,4-butanediol as a main component as a glycol component.

It is necessary that such sebacic acid is contained in at least 10 mol% of all the acid components, but in consideration of impact resistance, adsorption amount, etc., it is preferably 10 to 25 mol%, more preferably 15 to 25 mol%. Mol% is included.

As the acid component, other dibase may be used in combination with the above sebacic acid, but the dibasic acid which can be used in combination is not particularly limited, and examples thereof include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid. Etc. can be used.

Further, the glycol component contains 1,4-butanediol as a main component, but it can also be used as a mixture with other diols such as ethylene glycol and neopentyl glycol. In this case, it is desirable that the main component, 1,4-butanediol, be contained in at least 50 mol% or more in all glycol components. 50 mol%
If it is less than the above range, the resulting resin may have poor flexibility and impact resistance may deteriorate.

The above flexible polyester resin can be easily obtained by using a known polyester resin synthesizing means.

The thickness of the polyester resin film of the present invention is at least 40 μm, preferably 50 to 80 μm in consideration of impact resistance and the like.

The polyester resin of the present invention does not adsorb or sorb a scent component, an effective component, etc., and does not elute low molecular weight components or various additives into the contents. Furthermore, the polyester resin of the present invention has good heat sealability. Practically, the adhesive strength after heat sealing is at least
It is necessary that the width is 2.3 kg / 15 mm width or more, preferably 2.5 kg / 15 mm width or more, and the polyester resin of the present invention sufficiently satisfies this condition. Therefore, conventionally, it was laminated with a heat-adhesive resin film in order to have a heat-sealing property, but in the present invention, the labor of this lamination is saved, and it is advantageous in terms of productivity and cost.

The composite film constituting the packaging material of the present invention is specifically a laminate of a base film made of at least one film or sheet on the polyester resin of the present invention. As the material film, polyethylene, a polyolefin resin such as polypropylene, a polyethylene terephthalate or other polyester resin, a commonly used stretched or unstretched resin layer such as polyvinyl chloride, polystyrene, polycarbonate, polyamide, or poly, Resin layer with excellent gas barrier properties such as vinylidene chloride, polyvinyl alcohol, polyacrylonitrile, metal foil, metal or metal oxide,
A thin film layer of an inorganic oxide or an inorganic compound, further,
It is possible to use paper, non-woven fabric, or the like, which is used alone or a plurality of which are laminated according to the purpose. More specifically, the constitution of aluminum foil / polyester resin film, stretched nylon film, polyvinylidene chloride resin layer / stretched nylon film, stretched nylon film / aluminum foil / polyester resin film, polypropylene / polyvinyl alcohol / polypropylene, etc. It can be illustrated.

The aluminum foil has a thickness of 9 μm to 15 μm.
The adhesive used in dry laminating with the polyester resin of the present invention or the polyester of the outermost layer is, for example, an ester adhesive (Takelac A 515; Takeda Pharmaceutical Co., Ltd.). Manufactured etc.) and the like.

The packaging material of the present invention as described above is most suitable as a packaging material for food contents including beverages, particularly for lightly flavored foods such as porridge, elephant and baby foods, which has been a tendency in recent years.

As the packaging material of the present invention, a liquid pouch requiring impact resistance, a film for food packaging used in a retort pouch, a food container such as a lid material for a liquid container requiring impact resistance, etc. Examples thereof include a film for packaging a pharmaceutical product which is used for a material such as a lid material, a poultice, or the like, whose active ingredients are significantly adsorbed and sorbed on a packaging film, or a medicine which has an expensive medicinal component and is required to be used in a reduced amount.

[0024]

EXAMPLES The present invention will be described in more detail with reference to the following examples.

After the polyester resin having the composition shown in Table 1 is polymerized and pelletized, it is formed into a film by the T-die method or the inflation method, or laminated on the substrate by the Neelham method or the extrusion method. A packaging material having the following constitution was prepared. Polyethylene terephthalate film (12 μm) / aluminum foil (9 μm) / polyester resin film (60 μm) of the present invention

A retort pouch was prepared using the obtained packaging material, filled with mineral water and heat-sealed, and then subjected to retort treatment at 120 ° C. for 30 minutes, and then dropped from a height of 120 cm onto a concrete surface. The impact resistance was evaluated by the number of drops until the bag was broken. Further, the whitening of the packaging material after the retort treatment was visually observed, and the taste of the contents was evaluated by a sensory test (a pairwise comparison with that of CPP was carried out, and the taste was checked by the χ ² test method).

The heat sealability and the amount of limonene adsorbed were also evaluated, and the adhesive strength after heat sealing and the amount of limonene adsorbed per unit weight (mg / g) were evaluated. The results are shown in Table 1.

[0028]

[Table 1] * 1 TPA: terephthalic acid SEA: sebacic acid BD: 1,4-butanediol CPP: unstretched polypropylene EG: ethylene glycol ADA: adipic acid * 2 ○: 5% better taste than CPP △: No significant difference × : CPP has better taste at 5% risk rate * 3 ○: No whitening △: Slight whitening ×: Whitening

As is clear from the above results, by using the polyester resin film containing at least 10 mol% of sebacic acid as the acid component and 1,4-butanediol as the glycol component, even after the retort treatment. It can be seen that the excellent impact resistance can be maintained and the problems of poor taste and whitening can be solved.

Also, in the above-mentioned embodiment, the packaging material constitution is the same as that of polyethylene terephthalate (12 μm) / aluminum foil (9 μm) / stretched nylon (15 μm) / polyester resin film (60 μm) of the present invention. As for the products evaluated in the above, those using the polyester resin of the present invention showed excellent effects similar to the above.

[0031]

As described in detail above, the use of a flexible polyester resin having sebacic acid as an acid component and having thermal adhesiveness reduces adsorption and sorption of scent components, active ingredients, etc. It is possible to provide a packaging material which does not elute low molecular weight components and various additives and is excellent in impact resistance, and which does not cause bad taste and whitening even when subjected to retort treatment.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masanobu Higashi 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd.

Claims (1)

[Claims] 1. A polyester containing 1,4-butanediol as a glycol component as a main component and sebacic acid as an acid component in an amount of at least 10 mol% on a side of a base film composed of at least one layer of a film or sheet, which is in contact with the contents. A packaging material comprising a resin layer.