JP2873823B2 - Packaging bag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention mainly relates to packaging materials used for standing pouches, packaging bags and the like.

[Conventional technology]

Conventional packaging materials used for containers and packaging bags containing various liquid foods and drinks, tea leaves, spices, etc., have a polyolefin-based resin layer which is an inner peripheral surface of the obtained package and has a heat-sealing property. It is formed into containers and packages of various shapes by utilizing the heat bonding performance (heat sealing property) between the polyolefin-based resins.

[Problems to be solved by the invention]

By the way, a packaging bag obtained by using a packaging material in which the layer on the inner peripheral surface of the conventional packaging body is formed of a polyolefin-based resin is a polyolefin-based resin layer when the packaging material is obtained. The polyolefin-based resin undergoes thermal decomposition to form volatile components such as aliphatic hydrocarbons during formation or when forming a packaging bag with the packaging material. For this reason, this volatile component migrates into the filling contained in the packaging bag, and there is an adverse effect that the filling has a taste and odor.

Therefore, the polyolefin-based resin layer, which is the inner heat sealant layer in the conventional packaging bag, also has a disadvantage that the flavor of the filling material changes and is easily damaged.

On the other hand, in order to improve the above-mentioned disadvantages of the polyolefin resin layer, the generation of volatile substances is small,
Moreover, a packaging material using a polyethylene terephthalate resin layer having a good scent retention property as an inner surface layer has been proposed. However, a packaging material having a single layer of the polyethylene terephthalate resin layer has a heat sealing strength (heat sealing strength). (Sealing strength) is weak, and there is a disadvantage that a packaging bag having a sufficient heat sealing strength cannot be obtained by heat welding (heat sealing) which is a conventional means for obtaining a packaging bag.

Therefore, the present invention eliminates all the drawbacks of the conventional packaging material in which the layer on the inner peripheral surface side of the packaging bag is formed of a polyolefin-based resin and the packaging material formed of a single layer of polyethylene terephthalate resin. To do
The filling material in the packaging bag of the present invention does not cause any unpleasant taste or odor, and the packaging means is exactly the same as the hot-pressure adhesive molding applied to the conventional packaging bag. It is an object of the present invention to provide a packaging bag having a sufficient heat sealing strength by a molding means utilizing a thermal bonding ability of a resin layer on a side to be an inner peripheral surface of the bag.

[Means for solving the problem]

The above problem is solved by the packaging bag of the present invention having the configuration described below.

That is, the present invention provides a first resin layer having a heat sealing property by a copolymer of a linear saturated polyester having a glass transition point of 40 ° C. or more, and a first resin layer directly laminated on the first resin layer. A co-extruded laminated material comprising a linear saturated polyester copolymer and a second resin layer of a polyolefin resin capable of hot-melt bonding is laminated to a packaging bag base material via an adhesive. A packaging bag used such that the first resin layer of the body is in contact with the internal filling, that is, the heat-sealing surface, and the second resin layer of the polyolefin resin is an ethylene-based resin. It is formed of a copolymer of a copolymer and an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic anhydride.

In the packaging bag of the present invention having the above-described configuration, the co-extruded laminated material containing the linear saturated polyester copolymer having a glass transition temperature of 40 ° C. or more is a linear saturated material forming the resin layer. It must have excellent fragrance retention at a temperature lower than the glass transition temperature of the polyester copolymer, and the internal additives in the packaging bag must be placed in an atmosphere at a normal temperature of less than 40 ° C. In view of the above, it is possible to utilize the excellent fragrance retention performance of the linear saturated polyester copolymer.

In addition, the linear saturated polyester copolymer having a glass transition temperature of 40 ° C. or higher is used as the packaging bag of the present invention, and excellent heat bonding strength is obtained in a heat bonded portion heat sealed by heat welding. It is preferable that the resin be as low as possible in crystallinity.

A linear saturated polyester copolymer having a glass transition temperature of 40 ° C. or higher includes, for example, alcohol components such as ethylene glycol, propylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol, and adipic acid and sebacic acid. Aliphatic dicarboxylic acids such as, terephthalic acid, isophthalic acid, is formed by a co-condensation polymer with a dicarboxylic acid component such as an aromatic dicarboxylic acid such as diphenyl dicarboxylic acid, specifically, ethylene glycol Terephthalic acid, ethylene glycol and isophthalic acid and terephthalic acid, 1,4-cyclohexane dimethanol and ethylene glycol and terephthalic acid, can be formed using a co-condensation polymer of propylene glycol and isophthalic acid and terephthalic acid, 10% by weight or more of aliphatic dicarboxylic acid component in acid component In the case of the co-condensation polymer, a linear saturated polyester copolymer based on this co-condensation polymer is not preferable because its fragrance retention performance tends to decrease.

For the formation of the second resin layer of the hot-melt adhesive polyolefin resin laminated on the first resin layer, which is a linear saturated polyester copolymer layer having a glass transition temperature of 40 ° C. or higher, for example, polyethylene, Ethylene-α-olefin copolymer, polypropylene, polybutene, α-olefins such as polyisobutylene, and polybutadiene, an ethylene-based polymer such as a polydiisoolefin such as polyisoprene or a copolymer thereof,
It is formed by a copolymer with ethylenically unsaturated carboxylic acid or ethylenically unsaturated carboxylic anhydride.

Specific examples of the ethylenically unsaturated carboxylic acid copolymerized with the ethylene polymer to obtain this hot-melt adhesive polyolefin resin include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, and itaconic acid. Citraconic acid, 5-norbornene-2,3-dicarboxylic acid, etc. Specific examples of the ethylenically unsaturated carboxylic anhydride include maleic anhydride, citraconic anhydride, 5-norbornene-
2-, 3-dicarboxylic anhydride, terahydrohydrophthalic anhydride and the like.

The co-extruded laminated material in the packaging bag of the present invention comprises a first resin layer made of a linear saturated polyester copolymer having a glass transition temperature of 40 ° C. or higher, and a heat layer directly laminated on the first resin layer. Second with melt adhesive polyolefin resin
A resin layer, wherein the second resin layer in the co-extruded laminated material enhances the heat sealing property of the first resin layer of the co-extruded laminated material. As a whole, it functions as a heat bonding layer (heat sealant layer) of the packaging bag of the present invention.

The first resin layer in the co-extruded laminate, that is, the linear saturated polyester copolymer having a glass transition temperature of 40 ° C. or higher, has a film-forming stability when the thickness of the layer is less than 5 μm. And heat seal strength are difficult to stabilize,
When the thickness exceeds μm, the co-extruded laminated material becomes hard, so that the adhesion of the heat-welded portion at the time of forming the packaging bag becomes poor, and the heat sealing strength becomes unstable. For this reason, the first resin layer preferably has a thickness in the range of 5 to 60 μm.

The thickness of the second resin layer made of the adhesive polyolefin-based resin layer is determined by the thickness of the base material for the packaging bag on which the co-extruded laminate made of the first resin layer and the second resin layer is laminated. Although it also differs depending on the adhesive property (cushioning property and the like) with the surface to be laminated, if the surface to be laminated in the base material for a packaging bag has a small cushioning action, for example, an aluminum foil surface, it is about 30 μm. It is enough.

The base material for a packaging bag on which the co-extruded laminate of the first resin layer and the second resin layer is laminated is generally made of a single material such as aluminum foil, biaxially stretched polyester film, and biaxially stretched polypropylene film. It is a layer or a laminated sheet, and the adhesion between the co-extruded laminated material and the base material for a packaging bag is generally performed using an isocyanate-based adhesive or the like.

〔Example〕

Hereinafter, a specific configuration example of the packaging bag of the present invention will be illustrated and described with reference to examples.

Example 1 In FIG. 1, one example of a packaging bag of the present invention denoted by reference numeral 1 is a linear saturated polyester copolymer having a glass transition temperature of 81 ° C. and a thickness of 20 μm [PETG6763: Eastman Kodak Co., Ltd. )), A first resin layer 2 formed by
A hot-melt adhesive polyolefin-based resin (Novatec AP220L: manufactured by Mitsubishi Kasei Co., Ltd.) obtained by graft-polymerizing maleic anhydride onto low-density polyethylene directly laminated on the first resin layer was applied to a second resin having a thickness of 40 μm. The co-extruded laminated material 4 (the heat-welded surface is the first resin layer) as the resin layer 3 of
Are laminated via the isocyanate-based adhesive 6 to the packaging bag base material indicated by.

The base material 5 for the packaging bag has a thickness 12
A composite film obtained by laminating a stretched polyester film having a thickness of 15 μm and a stretched polyamide film having a thickness of 15 μm represented by reference numeral 8 with an isocyanate-based adhesive 9 and an aluminum foil having a thickness of 9 μm represented by reference numeral 11 It is composed of a laminated sheet bonded and laminated with an isocyanate-based adhesive 7.

COMPARATIVE EXAMPLE 1 Except for removing the second resin layer 3 from the laminated structure of the packaging bag 1 in the above-mentioned Example 1, and changing the thickness of the first resin layer 2 which is the heat-welded portion to 60 μm, A packaging bag A having the same laminated configuration as the packaging bag 1 was prepared for comparison.

Comparative Example 2 A packaging bag B in which the first resin layer denoted by reference numeral 2 was replaced with a low-density polyethylene resin layer having a thickness of 60 μm as a heat-welded portion from the laminated configuration of the packaging bag 1 in Example 1 described above. Prepared for comparison.

[Experiment]

The fragrance preservation performance and the heat welding property of the above-mentioned example of the packaging bag of the present invention and each packaging bag for comparison were tested based on the following methods.

Preparation of the package Each of the above-described packaging bags, a 17 cm × 12 cm standing pouch, in which the outer peripheral layer (heat sealing surface) of each package is composed of the stretched polyester film layer in the packaging bag base material, Created by a heat welding method with the resin layer laminated on the packaging bag base material as a heat welding portion, furthermore
By filling 200 ml of 100% orange juice, three types of packages were prepared for 10 pieces.

Flavor retention performance and impact resistance test The results of the orange juice flavor test after storing the above three types of packages in a 37 ° C atmosphere for one week, and repeating the above packages from a height of 90 cm The state of liquid leakage of each package when dropped twice was observed.

 The results are shown in Table 1.

[Action and Effect of the Invention] The present invention is directed to laminating a first resin layer of a linear saturated polyester copolymer having a glass transition temperature of 40 ° C. or more, and directly co-extrusion with the first resin layer. The co-extruded laminated material comprising the second resin layer of the hot-melt adhesive polyolefin resin is in contact with the base material for the packaging bag, and the first resin layer in the co-extruded laminated material is in contact with the internal additive. A packaging bag comprising a packaging bag laminated as described above, and used such that the first resin layer is on the side in contact with the internal additive inside the package, and the above-mentioned heat-melting bag is also used. The second resin layer made of the adhesive polyolefin resin is formed of a copolymer of an ethylene resin polymer and an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic anhydride.

Thus, the first resin layer of the linear saturated polyester copolymer having a glass transition temperature of 40 ° C. or more in the co-extruded laminated material of the packaging bag of the present invention having the above-described structure has an aroma retaining property. It has excellent action in
Further, a second resin layer of a hot-melt adhesive polyolefin resin directly laminated on the first resin layer, that is, a copolymer of an ethylene polymer and an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic anhydride. The second resin layer made of a polymer compensates for the poor heat sealing performance, which is a weak point of the first resin layer, and acts synergistically to obtain practical heat sealing strength. Packaging bag.

In the packaging bag of the present invention, the side in contact with the internal additive is a first resin layer in the packaging bag, that is, a resin layer of a linear saturated polyester copolymer having a glass transition temperature of 40 ° C. or more. .

In the package using the packaging bag of the present invention, the volatile component caused by the polyolefin resin layer in the packaging bag does not migrate into the internal additive contained in the container or the packaging bag. Further, the flavoring component of the internal additive is not adsorbed in the packaging bag or does not pass through the packaging bag, so that the package has excellent fragrance retention.

Further, according to the packaging bag of the present invention, by using the co-extruded laminated material in the packaging bag as a heat-sealing portion, the packaging bag has a sufficient heat sealing strength.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing a laminated structure of one embodiment of a packaging bag of the present invention. 1: Packaging bag, 2: First resin layer of linear saturated polyester copolymer having a glass transition temperature of 40 ° C. or more, 3: Ethylene polymer and ethylenically unsaturated carboxylic acid or ethylenically unsaturated Second resin layer of adhesive polyolefin resin composed of a copolymer with carboxylic acid, 4: Coextruded laminated material 5: Base material for packaging bag 6: Coated extruded laminated material and aluminum foil of packaging substrate Isocyanate-based adhesive 7: Isocyanate-based adhesive between stretched polyamide film and aluminum foil 8: Stretched polyamide film 9: Isocyanate-based adhesive between stretched polyamide film and stretched polyester film 10: Stretched polyester film 11: Aluminum foil

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-48344 (JP, A) JP-A-54-135860 (JP, A) JP-A-61-255856 (JP, A) JP-A-61-255856 233538 (JP, A) JP-A-54-82 (JP, A) JP-A-56-159 (JP, A) JP-A-60-97849 (JP, A)

Claims (1)

(57) [Claims] 1. A first resin layer having a heat sealing property made of a copolymer of a linear saturated polyester having a glass transition point of 40 ° C. or more, and directly laminated on the first resin layer. A laminate formed by laminating a co-extruded laminate comprising a linear saturated polyester copolymer and a second resin layer made of a polyolefin resin capable of hot-melt bonding to a base material for a packaging bag via an adhesive A packaging bag used in such a manner that the first resin layer on the side in contact with the internal filling is used,
And a second resin layer made of the polyolefin resin is formed of a copolymer of an ethylene polymer and an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic anhydride. .