JP2008207868A - Liquid soup packaging material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid soup packaging material filled with a liquid as contents, which is excellent in gas-barrier properties and pressure resisting performance, and which can be easily disposed of by incineration. <P>SOLUTION: A supporting base material film is a base material composed of a transparent oriented polyamide film. The liquid soup packaging material is composed of a polyamide film laminate 10 in which a primer layer 2, a vapor deposition layer 3 and a protective coating layer 4 are sequentially superposed at least on one surface of the polyamide film base material 1. A printed layer 5 and/or a heat-sealing layer 6 are/is provided on the protective coating layer 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid soup wrapping material having a gas barrier property using a polyamide film.

  In recent years, the packaging form of foods has also changed significantly, and the deterioration in product quality due to the effects of temperature changes, humidity, oxygen gas, etc. in the distribution and sales process is not only from sales losses but also from food sanitation. It is a big problem. Under such circumstances, there is an increasing demand for packaging films that have low gas and moisture permeability and do not cause quality degradation as food.

  That is, it is important to maintain the taste and freshness by suppressing the oxidation and alteration of proteins, fats and oils of food ingredients. For this purpose, it is desired to block the permeation of air and gas using a packaging material having a good gas barrier property. Moreover, packaging with a gas barrier film retains the aroma of the contents and prevents moisture from passing through, so moisture absorption deterioration is suppressed in dry products, and in the case of hydrated materials, alteration and solidification due to moisture volatilization. Is suppressed, and a fresh flavor during packaging can be maintained for a long time.

  For these reasons, gas barrier properties and moisture resistance required for packaging films are extremely important characteristics. These characteristics are not limited to the food packaging film as described above, but are also extremely important for packaging films for medical products and electronic parts.

  As a gas barrier packaging material, a packaging material using a metal foil made of metal such as aluminum is excellent in gas barrier properties, but it must be treated as an incombustible material when discarded after use. There is a problem that the contents cannot be confirmed through seeing through, and it is difficult to check for a sealing failure at the time of filling seal, and there is a problem that foreign matter cannot be detected by a metal detector. there were. In addition, a metal barrier such as aluminum laminated as a gas barrier layer has good gas barrier properties and excellent economics, but does not transmit microwaves and cannot be heat-treated by a microwave oven.

  Further, coating with vinylidene chloride or the like as a gas barrier layer is inexpensive and economical, but does not have sufficient gas barrier properties against water vapor, oxygen gas, and the like. For vinylidene chloride, air pollution problems occur due to generation of dioxins and chlorine gas during incineration.

  Therefore, in recent years, as a so-called dechlorinated and dealuminated gas barrier packaging material that does not use vinylidene chloride, aluminum metal foil, etc., a vapor deposited film formed of an inorganic oxide on a plastic substrate such as a polyester film is used. Has come to be used a lot.

  Generally, a liquid soup wrapping material is required to have a piercing property, impact resistance, and pinhole resistance, so that the base material is preferably a polyamide film. However, since the polyamide film has a lower glass transition point and is softer than the polyester film, there is a problem that it is difficult to uniformly form a hard vapor deposition layer and the barrier property is hardly exhibited. In addition, since the adhesiveness is not sufficient in the packaging material in which the heat seal layer is laminated on the deposited film, the pressure resistance is low, and when used as a packaging material such as liquid soup, the lowermost layer bag is formed when boxed in cardboard. There were problems such as sacking.

The known literature is described below.
Publication 62-38140

  The present invention has been made to solve the above-described problems, and has an object to provide a liquid soup packaging material that has excellent gas barrier properties, is easy to incinerate, and has excellent pressure resistance. To do.

  The invention according to claim 1 of the present invention is a liquid soup packaging material filled with a liquid as a content, wherein a primer layer, a thin film deposition layer, and a protective coating layer are sequentially formed on at least one side of a substrate made of a transparent stretched polyamide film. A liquid soup packaging material comprising a laminated body as a constituent element.

  The invention according to claim 2 of the present invention is the liquid soup packaging material according to claim 1, wherein a printing layer and / or a heat seal layer is provided on the protective coating layer.

  In the liquid soup packaging material using the laminate film of the polyamide film base of the present invention, it is a liquid soup packaging material having excellent gas barrier properties and pressure resistance, and when used as a packaging material for liquid soup, pinhole resistance The bag is not broken due to piercing properties, impact resistance, weighting, etc., and air pollution does not occur due to generation of dioxin and chlorine gas during incineration.

  Examples of the liquid soup packaging material of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a gas barrier film laminate for a liquid soup packaging material according to the present invention. FIG. 1 shows an example of a liquid soup packaging material having a laminate as a constituent element. On a polyamide film substrate (1) as a support substrate, a primer layer (2), a vapor deposition layer (3), and The protective coating layer (4), the printing layer (5), and the heat seal layer (6) are sequentially laminated.

  Since the liquid soup packaging material is required to have piercing property, impact resistance, and pinhole resistance, the film base material needs to be a polyamide film. The polyamide film substrate (1) is made of a nylon resin having excellent flexibility among plastic materials, and a stretched transparent film is good. The transparent stretched polyamide film is, for example, nylon 6 obtained by ring-opening polymerization reaction of ε-caprolactam, nylon 66 obtained by polycondensation reaction of hexamethylenediamine and adipate, metaxylenediamine and adipic acid. A general-purpose single layer film made of MXD6 nylon, nylon 11, nylon 12 or the like obtained in this way is used. The stretching method may be a biaxial stretching method or a sequential stretching method. The thickness is preferably in the range of 12 to 25 μm from the viewpoint of film formability and economic efficiency. In addition, various additives and stabilizers such as an antistatic agent, an ultraviolet ray preventing agent, a plasticizer, and a lubricant may be used for the polyamide film substrate (1). The surface of the polyamide film substrate (1) may be subjected to corona treatment, low temperature plasma treatment, or ion bombardment treatment as pretreatment.

  Further, the polyamide film substrate (1) may be subjected to chemical treatment, solvent treatment and the like. If an easy-adhesion layer is provided on one or both sides of the polyamide film, the adhesion with the primer layer is improved, so there may be easy adhesion when used for containers with shapes or structures that require more physical stress. desirable.

  Next, the primer layer (2) will be described. The primer layer (2) is provided for the purpose of enhancing the adhesion between the base material and the thin film layer and suppressing a decrease in laminate strength due to the influence of the contents. Any resin material can be used as the primer resin as long as it can improve the adhesion between the substrate and the thin film layer. The primer layer is an organic polymer obtained by a two-component reaction of an isocyanate compound with a polyol such as acrylic polyol, polyvinyl acetal, polyester polyol or polyurethane polyol, or an organic compound having a urea bond by reaction with a polyisocyanate compound and water. Compounds, polyethyleneimine or derivatives thereof, polyolefin emulsions, polyimides, melamines, phenols, inorganic silicas such as organically modified colloidal silica, organic silane compounds such as silane coupling agents and hydrolysates thereof, etc. Any of these can be used as primer agents. In addition, two or more of these may be used in combination. In general, it is desirable to coat so that the thickness after drying is in the range of 50 to 50,000 mm, and more preferably in the range of 100 to 10,000 mm. When the thickness is less than 100 mm, it is difficult to obtain a uniform coating film from the viewpoint of coating technology. On the contrary, when it exceeds 1 μm, it is uneconomical.

  Next, the thin film vapor deposition layer (3) made of an inorganic compound will be described. The vapor deposition layer (3) made of an inorganic compound is a layer made of an oxide of silicon, aluminum, titanium, zirconium, tin, magnesium, etc., nitrogen, fluoride, or a composite thereof. Formation of the vapor deposition layer The method is formed by a vacuum process such as a vacuum deposition method, a sputtering method, or a plasma vapor deposition method. In particular, aluminum oxide is colorless and transparent, excellent in boiling sterilization, sterilization by heating and pressure, and can be used for a wide range of applications. The film thickness of the vapor deposition layer (3) varies depending on the application, but is preferably in the range of 20 to 5000 mm. However, if the thickness is less than 50 mm, there is a problem in the continuity of the thin film. Is preferably 50 to 3000 mm.

  Furthermore, a protective coat layer (4) for protecting the vapor deposition layer can be formed on the vapor deposition layer (3) as necessary. The deposited layer is a very thin film, and is easily damaged by a physical stimulus such as rubbing. In some cases, the deposited layer may fall off the substrate. Therefore, it is meaningful to form the protective coat layer after forming the vapor deposition layer and before performing other processing.

The protective coat layer (4) will be described. As the protective coating layer, an arbitrary resin may be formed by a method such as coating. As long as the vapor deposition layer is protected, a polyol such as acrylic polyol, polyvinyl acetal, polyester polyol polyurethane polyol, or the like and an isocyanate compound are used. Organic polymer obtained by liquid reaction, or organic compound having urea bond by reaction with polyisocyanate compound and water, polyethyleneimine or its derivative, polyolefin emulsion, polyimide, melamine, phenol, organically modified colloidal silica, etc. Non-aqueous protective layers such as inorganic silica and organic silica such as silane coupling agent, polyvinyl alcohol, starch, cellulose, emulsion acrylic polymer, SBR latex, polyvinyl acetate , Ethylene-vinyl copolymer, it may be a water-based protective layer, such as a silane coupling agent or a metal alkoxide and silane compounds such as hydrolysis. Two or more of these materials may be used in combination. For example, a mixture of polyvinyl alcohol, which is a water-soluble polymer, a metal alkoxide, and a hydrolyzate thereof has good adhesion to the vapor deposition layer and good barrier properties. The protective coating layer (4) of the gas barrier coating of the present invention comprises Si (OR ¹ ) ₄ and R ² Si (OR ³ ) ₃ (R ¹ and R ² are CH ₃ , C ₂ H ₅ , C ₂ H ₄ OCH ₃ such hydrolyzable group, R ² represents an organic functional group), in a silicon compound or hydrolyzate thereof represented, those formed by solution coating heated dry mixed with the water-soluble polymer having a hydroxyl group Is preferred.

A water-soluble polymer having a silicon compound, a hydrolyzate thereof, and a hydroxyl group in consideration of water resistance, adhesion to ink or adhesive, wettability, and prevention of cracking due to shrinkage in the protective coating layer (4) Add silane coupling agents, isocyanate compounds, clay minerals such as colloidal silica and smectite, known additives such as stabilizers, colorants, viscosity modifiers, etc. to the mixed solution, and apply and dry. You can also.

  A printing layer can also be provided on the protective coating layer (4). The printing layer (5) is formed for practical use as a packaging bag or the like, and conventionally used ink binders such as urethane, acrylic, nitrocellulose, rubber and vinyl chloride. It is a printing layer composed of ink obtained by adding various pigments, extender pigments and additives such as plasticizers, desiccants, stabilizers, etc. to the resin, and letters, pictures, etc. are formed. As a forming method, for example, a known printing method such as an offset printing method, a gravure printing method, a silk screen printing method, or a known coating method such as a roll coating, a knife edge coating, or a gravure coating can be used. The thickness may be 0.1 to 2.0 μm.

  Moreover, when using the laminated body for liquid soup packaging materials of this invention as a packaging material, it is preferable to form the heat seal layer (6) which consists of a polyolefin-type thermoplastic resin in the side used as the uppermost surface of a laminated body. Moreover, in the packaging material using this laminated body, an intermediate | middle layer can be provided as needed. This intermediate layer is provided to further functionalize the packaging material, such as imparting tearability and increasing the waist strength of the packaging material. Any material can be selected and used according to consumer requirements, suitability of contents, etc. be able to. For example, when imparting tearability, a uniaxially stretched nylon film, a uniaxially stretched polyethylene terephthalate film, a uniaxially stretched polypropylene film, or the like can be used. In order to increase waist strength, a biaxially stretched polyethylene terephthalate film or a biaxially stretched film can be used. A plastic material such as a polypropylene film can be used.

  The thickness of the intermediate layer is determined according to the material, required quality, required physical properties, etc., but is generally in the range of 10 to 30 μm. As a method for forming the intermediate layer, a known method such as a dry laminating method in which an adhesive such as a two-component curable urethane resin is bonded or an extrusion laminating method in which a heat-melted resin is extruded and bonded in a curtain shape is used. Although it can be laminated by using, generally a dry lamination method is often used.

  The heat seal layer (6), for example, a polyethylene-based thermoplastic resin layer, is used for an adhesive part when forming a bag-like package or the like. In addition, for example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer Resins such as ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, and metal cross-linked products thereof are used. The thickness is determined according to the purpose, but is generally in the range of 15 to 200 μm. As a forming method, a film-like product made of the above resin is bonded by using an adhesive such as a two-component curable urethane resin, a method of laminating by a non-solvent laminate, and the resin is heated and melted to form a curtain. Any of the extrusion laminating method, the extrusion method, and the knee laminating method can be laminated by a known method.

  On the opposite side of the stretched polyamide film substrate (1), a plurality of resins can be laminated via a printing layer, a heat seal layer, and an adhesive.

  The gas barrier laminate for the liquid soup packaging material of the present invention will be further described with specific examples. FIG. 2 is a side sectional view showing Example 1 of the layer configuration of the liquid soup packaging material according to the present invention. Hereinafter, Embodiments 1 to 3 of the present invention will be described with reference to FIG.

In the liquid soup wrapping material of the present invention, the protective coating liquid is prepared by adding 89.6 g of hydrochloric acid (0.1N) to 10.4 g of tetraethoxysilane, stirring for 30 minutes, and hydrolyzing to a solid content of 3 wt% (in terms of SiO2). After preparing a hydrolysis solution (liquid A) and a 3 wt% water / isopropyl alcohol solution (water: isopropyl alcohol weight ratio 90:10) liquid (liquid B) of polyvinyl alcohol, the liquid A and liquid B What was mixed with 60/40 by the mixture ratio (wt%) was made into the protective coating liquid.

As the support base film, a polyamide film base (1) was a biaxially stretched nylon film (Unitika Ltd., Emblem ONM) having a thickness of 15 μm and subjected to corona treatment on one side. A primer layer (2) made of a polyester resin and an isocyanate compound was laminated on the corona-treated surface of the biaxially stretched nylon film using a gravure coater. Next, the vapor deposition layer (3) which consists of aluminum oxide with a thickness of 12 nm was laminated | stacked on the primer layer (2) with the vacuum vapor deposition apparatus. Further, a protective coating layer (4) composed of a dried coating having a thickness of 0.2 μm was laminated by applying a protective coating solution on the vapor deposition layer (3) again with a gravure coater to obtain a polyamide film laminate. It was. Furthermore, the printing layer (5) was laminated | stacked on the protective coat layer (4) of the polyamide film laminated body by gravure printing. Next, the extrusion lamination method, after forming the anchor coat layer (7) a two-component curable urethane solution was about 0.3 g / m ² coated by gravure coating on the printing layer (5), extrusion lamination A heat-seal layer made of a linear low-density polyethylene having a thickness of 60 μm after laminating a linear low-density polyethylene having a thickness of 30 μm and further laminating a linear low-density polyethylene having a thickness of 30 μm. (6) was formed. Thereafter, the laminate film of Example 1 used for the liquid soup packaging material of the present invention was obtained by curing at 40 ° C. for 5 days (see FIG. 2).

  In Example 1, 5 w% of the silane coupling agent was added to the protective coating solution with respect to the total solid content to form the protective coating layer (4). A laminate film of the polyamide film of Example 2 to be used was obtained (see FIG. 2).

  Example 3 was carried out as a comparative example with respect to Example 1 and Example 2 of the present invention. The third embodiment will be described below.

  Example 3 which is a comparative example of the present invention is the same as Example 1 except that a vinylidene chloride-coated nylon film having a thickness of 15 μm was used instead of the polyamide film substrate (1) of the supporting substrate film in Example 1. A laminate film of Example 3 used for the liquid soup packaging material having the same layer constitution, that is, the layer constitution of the laminate of the polyamide film of the present invention was obtained (see FIG. 2).

  Subsequently, the quality characteristic as a liquid soup packaging material was evaluated by Evaluation 1 to Evaluation 4 of the laminated film of Example 1 and Example 2, the laminated film of the polyamide film and the laminated film of Example 3. This will be described below.

  As evaluation 1, the oxygen permeability of the film samples of the laminate films of the polyamide films of Examples 1 and 2 and the laminate film of Example 3 was measured. Based on JIS-7126B, it measured in the environment of temperature 30 degreeC and humidity 70% RH with the oxygen permeability measuring apparatus (OX-TRAN 10 / 50A: Product made by Modern Controls).

  As evaluation 2, a 10 cm square four-side sealed notched bag was prepared using the film samples of Examples 1, 2 and Example 3, and 50 g of commercially available noodle soup was filled as the contents. Part of this noodle soup sachet is filled into cardboard boxes of length + width + height = 100 cm without any gaps, sealed and transported back and forth between Tokyo and Osaka by courier, and the sachet breakage after transport It was confirmed.

  As evaluation 3, the remaining part of the sachet containing the noodle soup prepared in evaluation 2 was stored in an accelerated test room at 40 ° C. and 90% RH for 2 weeks, and the taste of noodle soup was subjected to a sensory test before and after storage. The case where the flavor of the noodle soup did not change was indicated as ◯, and the case where the taste was changed was indicated as ×.

  As Evaluation 4, a combustion test was conducted using the polyamide film laminate film of Examples 1 and 2 and the laminate film of Example 3. In this combustion test, ◯ indicates that no chlorine gas was emitted, and X indicates that chlorine gas was emitted. The results of Evaluation 1 to Evaluation 4 are shown in Table 1 below.

なお、燃焼試験の評価では、○は、塩素ガスが出ない、
×は、塩素ガスが出る。

In the evaluation of the combustion test, ○ indicates that no chlorine gas is emitted.
X indicates chlorine gas.

  From Table 1, the laminated film of the polyamide film of Examples 1 and 2 has a higher barrier property and is superior to the laminated film of the vinylidene chloride coated film of Example 3. Good pressure resistance and no bag breakage due to transportation tests. Further, even in the accelerated storage test at 40 ° C. and 90% RH, the polyamide film laminates of Examples 1 and 2 have high barrier properties and can prevent changes in the taste of the contents. Furthermore, there is no generation of chlorine gas in the combustion test.

It is a sectional side view which shows one Example of the laminated constitution of the liquid soup packaging material concerning this invention. It is a sectional side view which shows Examples 1-3 of the layer structure of the liquid soup packaging material concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Polyamide film base material 2 ... Primer layer 3 ... Deposition layer 4 ... Protective coating layer 5 ... Print layer 6 ... Heat seal layer 7 ... Anchor coating layer 10 ... Polyamide film laminated body 20 ... Polyamide film laminated body for liquid soup packaging materials

Claims (2)

  In a liquid soup wrapping material filled with a liquid as a content, a laminated body in which a primer layer, a thin film deposition layer, and a protective coating layer are sequentially laminated on at least one side of a substrate made of a transparent stretched polyamide film is used as a constituent element. Characteristic liquid soup packaging.   The liquid soup packaging material according to claim 1, wherein a printing layer and / or a heat seal layer is provided on the protective coating layer.

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