JP5498749B2 - Packaging materials - Google Patents

Description

  The present invention relates to a packaging material. More specifically, the present invention relates to a packaging material used for packaging foods, beverages, pharmaceuticals, cosmetics, chemicals, and the like. In particular, the present invention relates to a packaging material excellent in non-adhesiveness and oxygen absorption of contents.

  A wide variety of packaging materials are known in the past, but their contents are also diverse. For example, there are foods, beverages, pharmaceuticals, cosmetics, chemicals and the like such as jelly confectionery, pudding, yogurt, liquid detergent, toothpaste, carrero, syrup, petrolatum, face wash cream, face wash mousse and the like. In addition, the contents have various properties such as solid, semi-solid, liquid, viscous material, and gel-like material.

The packaging materials for packaging these contents are required to have hermeticity as well as thermal adhesiveness, light shielding, heat resistance, durability, etc. depending on the contents, packaging form, application, etc. The
However, even packaging materials that satisfy these characteristics have the following problems. That is, there is a problem that the contents adhere to the packaging material. If the contents adhere to the packaging material, it becomes difficult to use up all the contents, resulting in waste. In addition, in order to use up all the contents, the contents attached to the packaging material must be collected separately, which is troublesome. For this reason, the packaging material needs to have a property (non-adhesiveness) that the contents are difficult to adhere to the packaging material in addition to the above-described sealing property and the like.

  On the other hand, in a lid provided with a base material layer and a heat seal layer integrated through an adhesive layer, the heat seal layer has an anti-adhesion effect, glyceric acid ester, polyglycerin fatty acid ester, pentaerythritol fatty acid. It consists of polyolefin containing ester, polyoxypropylene / polyoxyethylene block polymer, sorbitan fatty acid ester, polyoxyethylene alkyl ether, fatty acid amide, etc., and its thickness is thicker than 10 μm, between the adhesive layer and the heat seal layer There has been proposed a filler adhesion prevention lid material characterized in that an intermediate layer made of polyolefin is provided (Patent Document 1).

JP 2002-37310 A

  In a lid material like patent document 1, the kind or thickness of the heat seal layer which can be used is restricted, and the amount of additives such as glycerate must be strictly controlled. When the amount of the additive used is too large, the heat sealing performance is lowered. On the other hand, when the amount of the additive used is reduced, the adhesion preventing effect is lowered accordingly. In this respect, there is room for further improvement in promoting practical use.

  Another problem is that most foods, beverages, pharmaceuticals, etc. undergo chemical changes such as spoilage, decomposition or oxidation in the presence of oxygen, and their storage period and commercial value are drastically reduced. Furthermore, in fermentable foods and drinks such as yogurt, cheese, miso, pickles, fermented liquor, and fermented beverages, the internal pressure in the package increases due to the progress of fermentation, and the contents scatter when the lid is opened. May occur. These problems have not yet been solved by the prior art.

  Therefore, a main object of the present invention is to provide a packaging material that can continuously exhibit excellent non-adhesiveness while maintaining good thermal adhesiveness and excellent in oxygen absorption.

  As a result of intensive studies in view of the problems of the prior art, the present inventor has found that the above object can be achieved by adopting a laminate having a specific structure as a packaging material, and has completed the present invention. It was.

That is, the present invention relates to the following lid material .
1. A lid member comprising a laminate having at least a base material layer and a thermal adhesive layer, wherein the thermal adhesive layer is laminated as an outermost layer on one surface of the lid material , and at least the base material layer and the thermal adhesive layer Hydrophobic oxide fine particles having an average primary particle diameter of 3 to 100 nm are attached to the outermost surface that contains an oxygen absorbent on one side and the thermal adhesive layer is not adjacent to other layers, and the hydrophobic oxide fine particles are in a three-dimensional network. Forming a porous layer of a structure, filled with contents in a container, and sealed in a state in which the opening and the thermal adhesive layer of the lid are in contact with each other,
A lid material in which hydrophobic oxide fine particles existing on a region to be thermally bonded are embedded in the thermal bonding layer at the time of thermal bonding .
2. Item ^2. The cover material according to Item 1, wherein the amount of hydrophobic oxide fine particles adhered is 0.01 to 10 g / m2.
3. Item 3. The lid according to Item 1 or 2, wherein the content is a fermented food or drink .
4). Item 4. The lid material according to any one of Items 1 to 3, wherein the hydrophobic oxide fine particles have a specific surface area of 50 to 300 m ² / g by BET method.
5. Item 5. The lid according to any one of Items 1 to 4, wherein the hydrophobic oxide fine particles are hydrophobic silica.
6). Item 6. The lid according to Item 5, wherein the hydrophobic silica has a trimethylsilyl group on the surface thereof.
7). Item 7. The lid according to any one of Items 1 to 6, wherein the oxygen absorbent includes metal particles in which at least a part of a particle surface is coated with at least one of a resin component and an inorganic oxide.
8). Item 8. The lid material according to any one of Items 1 to 7, which is used for a product in which the content is packaged by a lid material and a container in a state in which the content can come into contact with the outermost surface on the thermal adhesive layer side.

  The packaging material of the present invention can exhibit excellent non-adhesiveness and oxygen absorption while maintaining good thermal adhesiveness. That is, high non-adhesiveness can be obtained without impeding the thermal adhesiveness practically without being restricted by the type and thickness of the thermal adhesive layer. More specifically, at the time of thermal bonding, the hydrophobic oxide fine particles existing on the heat-bonded region are embedded in the heat-bonding layer and thus do not inhibit the heat-bonding, but exist outside the heat-bonded region. Since the hydrophobic oxide fine particles are held on the thermal adhesive layer as they are, their high non-adhesiveness can be exhibited.

  In addition, since at least one of the base material layer and the thermal adhesive layer contains an oxygen absorbent, the oxygen absorbent particles exhibit desired oxygen absorption performance while avoiding falling off due to contact of contents and the like. be able to. In particular, when the layer composed of the hydrophobic oxide fine particles formed on the thermal bonding layer is formed in a porous shape (that is, when a porous layer is formed), it has high non-adhesiveness, Higher oxygen absorption performance can be exhibited. In this case, oxygen remaining in the package or oxygen generated from the contents can penetrate through the porous layer and reach the oxygen absorbent contained in the thermal adhesive layer or the like more reliably. As a result, oxygen can be more effectively absorbed and removed by the oxygen absorbent, and high non-adhesiveness can be exhibited by forming the porous layer.

  Such packaging materials can be used as lidding materials, and are effective for various uses such as pillow bags, gusset bags, self-supporting bags, three-side seal bags, four-side seal bags, etc., molded containers, packaging sheets, tubes, etc. Can be used.

It is a schematic diagram of the cross-sectional structure of the packaging material which concerns on one Embodiment of this invention. It is a schematic diagram of the cross-sectional structure of the package produced using the packaging material of the present invention as a container lid.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Thermal adhesive layer 3 Hydrophobic oxide fine particle 4 Container 5 Contents 6 Oxygen absorber (main agent particle)

1. Packaging material The packaging material of the present invention is a packaging material comprising a laminate having at least a base material layer and a thermal adhesive layer, wherein the thermal adhesive layer is laminated as an outermost layer on one surface of the packaging material, Hydrophobic oxide fine particles having an average primary particle diameter of 3 to 100 nm are attached to the outermost surface that includes an oxygen absorbent in at least one of the base material layer and the thermal adhesive layer, and the thermal adhesive layer is not adjacent to the other layers. It is characterized by being.

  FIG. 1 shows a schematic diagram of a cross-sectional structure of a packaging material according to an embodiment of the present invention. The packaging material of FIG. 1 is composed of a laminate in which a thermal adhesive layer 2 is laminated on a base material layer 1. The thermal adhesive layer 2 is laminated on one outermost layer of the packaging material (laminate). In this packaging material, the oxygen absorbent 6 is contained in the thermal adhesive layer 2. However, some particles of the oxygen absorbent 6 may exist so as to straddle between the base material layer 1 and the heat bonding layer 2. In the thermal bonding layer 2 that is the outermost layer, hydrophobic oxide fine particles 3 having an average primary particle diameter of 3 to 100 nm are attached to the surface (outermost surface) on the side that is not adjacent to another layer (base material layer in FIG. 1). doing. The hydrophobic oxide fine particles 3 are adhered and fixed to the heat bonding layer 2. That is, even if the hydrophobic oxide fine particles and the content come into contact with each other, the hydrophobic oxide fine particles are adhered to such an extent that they do not fall off. In FIG. 1, the hydrophobic oxide fine particles 3 may contain primary particles, but it is desirable that the hydrophobic oxide fine particles 3 contain many aggregates (secondary particles). In particular, it is more preferable that the hydrophobic oxide fine particles form a porous layer having a three-dimensional network structure. That is, it is preferable that a porous layer having a three-dimensional network structure formed of hydrophobic oxide fine particles is laminated on the thermal bonding layer 2.

  In FIG. 2, the schematic diagram of the cross-sectional structure of the package body produced using the packaging material of this invention as a cover material of a container is shown. In FIG. 2, the notation of the hydrophobic oxide fine particles 3 and the oxygen absorbent 6 is omitted. The container 4 is filled with the contents 5 and sealed in such a state that the opening and the thermal adhesive layer 2 of the packaging material are in contact with each other. That is, the packaging material of the present invention is used in a state where the hydrophobic oxide fine particles adhering to the heat bonding layer 2 can come into contact with the contents 5. Even in such a case, the thermal adhesive layer 2 is protected by the hydrophobic oxide fine particles and has excellent non-adhesiveness. The adhesion of the contents to the thermal adhesive layer is blocked and repelled by the hydrophobic oxide fine particles (or the porous layer made of hydrophobic oxide fine particles). For this reason, the content does not remain in the vicinity of the thermal adhesive layer, but is repelled by the hydrophobic oxide fine particles (or the porous layer made of the hydrophobic oxide fine particles) and returns to the container. In addition, as a material of the container 4, it can select suitably from a metal, a synthetic resin, glass, paper, those composite materials, etc., The kind of a heat bonding layer, a component, etc. can be adjusted suitably according to the material.

  A known material or a laminated material can be adopted as the base material layer. For example, a simple substance such as paper, synthetic paper, a resin film, a resin film with a vapor deposition layer, an aluminum foil, or a composite material / laminated material thereof can be suitably used.

  In these materials, each layer employed in a known packaging material may be laminated at an arbitrary position. For example, a printing layer, a printing protective layer (so-called OP layer), a colored layer, an adhesive layer, an adhesion reinforcing layer, a primer coat layer, an anchor coat layer, an anti-slip agent layer, a lubricant layer, an anti-fogging agent layer, etc. Moreover, you may laminate | stack the resin layer containing the oxygen absorber mentioned later as needed.

  The lamination method in the case of using a laminated material is not limited, and known methods such as a dry lamination method, an extrusion lamination method, a wet lamination method, and a heat lamination method can be employed.

  Although the thickness of a base material layer is not limited, What is necessary is just to set suitably in 15-500 micrometers normally from viewpoints, such as the intensity | strength as a packaging material, a softness | flexibility, and cost.

  A well-known material can be employ | adopted as a heat contact bonding layer. For example, in addition to a known sealant film, a layer formed of an adhesive such as a lacquer type adhesive, an easy peel adhesive, or a hot melt adhesive can be employed. Among these, in the present invention, it is preferable to employ a lacquer type adhesive or a hot melt adhesive, and particularly a thermal adhesive layer (hot melt layer) formed by the hot melt adhesive can be suitably employed. When forming a hot melt layer, after applying the hot melt adhesive in a molten state, if the hydrophobic oxide fine particles are applied before cooling and solidifying, the hydrophobic oxide fine particles are allowed to adhere to the thermal adhesive layer as they are. Therefore, continuous production of the packaging material of the present invention is facilitated.

  The thickness of the thermal adhesive layer is not particularly limited, but it is usually preferably about 2 to 150 μm from the viewpoint of sealing performance, productivity, cost, and the like. In particular, in the packaging material of the present invention, when thermally bonding, the hydrophobic oxide fine particles existing on the heat bonded region are embedded in the heat bonding layer, and the heat bonding layer becomes the outermost surface so that the heat bonding is performed. It can be carried out. Therefore, it is desirable to set the thickness within the above thickness range so that as many hydrophobic oxide fine particles as possible can be embedded in the thermal adhesive layer.

  Hydrophobic oxide fine particles adhering to the thermal adhesive layer usually have an average primary particle diameter of 3 to 100 nm, preferably 5 to 50 nm, and more preferably 5 to 20 nm. By setting the average primary particle diameter in the above range, the hydrophobic oxide fine particles are in an appropriate aggregated state, and can hold a gas such as air in the voids in the aggregate, resulting in excellent non-adhesiveness. Can be obtained. That is, this agglomerated state is maintained even after adhering to the thermal adhesive layer, so that excellent non-adhesiveness can be exhibited.

  In the present invention, the average primary particle diameter can be measured with a scanning electron microscope (FE-SEM). When the resolution of the scanning electron microscope is low, other electrons such as a transmission electron microscope are used. You may carry out together with a microscope. Specifically, when the particle shape is spherical, the diameter is considered as the diameter, and when the particle shape is non-spherical, the average value of the longest diameter and the shortest diameter is regarded as the diameter, and 20 arbitrarily selected by observation with a scanning electron microscope or the like. The average diameter of the particles is defined as the average primary particle diameter.

The specific surface area of the hydrophobic oxide fine particles (BET method) is not particularly limited, and usually 50 to 300 m ² / g, it is preferable that the particular 100 to 300 m ² / g.

The hydrophobic oxide fine particles are not particularly limited as long as they have hydrophobicity, and may be those hydrophobized by surface treatment. For example, fine particles in which hydrophilic oxide fine particles are subjected to a surface treatment with a silane coupling agent or the like to make the surface state hydrophobic can also be used. The type of oxide is not limited as long as it has hydrophobicity. For example, at least one of silica (silicon dioxide), alumina, titania and the like can be used. These may be known or commercially available. For example, as silica, product names “AEROSIL R972”, “AEROSIL R972V”, “AEROSIL R972CF”, “AEROSIL R974”, “AEROSIL RX200”, “AEROSIL RY200” (above, manufactured by Nippon Aerosil Co., Ltd.), “AEROSIL R202” "AEROSIL R805", "AEROSIL R812", "AEROSIL R812S" (above, manufactured by Evonik Degussa). Examples of titania include “AEROXIDE TiO ₂ T805” (manufactured by Evonik Degussa). Examples of alumina include fine particles in which the product name “AEROXIDE Alu C” (manufactured by Evonik Degussa) is treated with a silane coupling agent to make the particle surface hydrophobic.

  Among these, hydrophobic silica fine particles can be preferably used. In particular, hydrophobic silica fine particles having a trimethylsilyl group on the surface are preferable in that better non-adhesiveness can be obtained. Examples of commercially available products corresponding to this include “AEROSIL R812” and “AEROSIL R812S” (both manufactured by Evonik Degussa).

The amount (weight after drying) of the hydrophobic oxide fine particles to be adhered to the thermal adhesive layer is not limited, but is usually preferably 0.01 to 10 g / m ^2, and preferably 0.2 to 1.5 g / m ^{2. 2} is more preferable, and 0.3 to 1 g / m ² is most preferable. By setting within the above range, more excellent non-adhesiveness can be obtained over a long period of time, and it is further advantageous in terms of suppression of falling off of hydrophobic oxide fine particles, cost, and the like. The hydrophobic oxide fine particles attached to the heat bonding layer preferably form a porous layer having a three-dimensional network structure, and the thickness is preferably about 0.1 to 5 μm, and preferably 0.2 to 2.5 μm. The degree is further preferred. By adhering in such a porous layer state, the layer can contain a lot of air, and more excellent non-adhesiveness can be exhibited.

  Further, the hydrophobic oxide fine particles may be attached to the entire surface of the thermal adhesive layer (the entire surface opposite to the base material layer side), or a region where the thermal adhesive layer is thermally bonded (so-called adhesive margin). It may be attached to the area excluding. In the present invention, even when adhering to the entire surface of the heat bonding layer, most or all of the hydrophobic oxide fine particles present on the heat bonded region are buried in the heat bonding layer, so that the heat bonding is hindered. In view of industrial production, it is desirable to adhere to the entire surface of the thermal adhesive layer.

  In the packaging material of the present invention, an oxygen absorbent is contained in at least one of the base material layer and the heat bonding layer.

  As the oxygen absorbent itself, a known or commercially available inorganic oxygen absorbent or organic oxygen absorbent can be used. More specifically, for example, an inorganic oxygen absorbent mainly composed of at least one fine powder of iron, silicon, aluminum, etc .; for example, organic oxygen absorption mainly composed of at least one kind such as ascorbic acid and unsaturated fatty acid. Agents. In particular, a main agent capable of irreversibly adsorbing oxygen is preferable.

  In addition, as the main component of the inorganic oxygen absorbent, it is also possible to use one in which at least a part of the surface of the metal particles is coated with a resin component or an oxide. For example, when aluminum-based particles are used as the metal particles, aluminum generally has a high reaction rate with oxygen, so that the speed can be adjusted by coating a part or all of the surface of the aluminum-based particles with a resin component. Commercially available aluminum-based particles (resin-coated Al-based particles) themselves coated with such a resin component can be used, and can also be prepared by known methods. In addition, for example, a known method can also be adopted when coating with an oxide (inorganic oxide). More specifically, in addition to the so-called sol-gel method, for example, the method described in Japanese Patent No. 3948934 (the organosilicon compound is adjusted by adjusting the pH of a dispersion solution containing aluminum particles, an organosilicon compound, and a hydrolysis catalyst). It is possible to employ a method of hydrolyzing and depositing a silica film on the surface of aluminum particles to obtain oxide-coated aluminum particles.

  The content of the oxygen absorbent can be appropriately set according to the desired oxygen absorption performance or the like, but is usually 0.3 to 30% by weight as the content of the main agent in the base material layer or the thermal adhesive layer. It is preferable to set it as 1 to 20 weight% especially. By setting within the above range, excellent oxygen absorption performance can be obtained while maintaining desired thermal adhesiveness and the like.

  The oxygen absorbent may be contained in at least one of the base material layer and the thermal adhesive layer, but is preferably contained in at least the thermal adhesive layer from the viewpoint of obtaining oxygen absorption performance more effectively. The method for incorporating the oxygen absorbent in these layers is not limited as long as the oxygen absorbent can be uniformly dispersed. For example, the method of mixing an oxygen absorbent with the raw material for forming a base material layer or a heat bonding layer in advance is mentioned. The mixing can be performed with a known mixer, stirrer, or the like. In this case, either dry mixing or wet mixing may be used.

  Hereinafter, as a typical example of the oxygen absorbent, an inorganic oxygen absorbent using aluminum-based particles (or resin-coated Al-based particles) as a main agent will be described together with preferred embodiments thereof.

  The aluminum-based particles are not particularly limited as long as a predetermined oxygen absorption performance is expressed. For example, in addition to pure aluminum particles, various aluminum alloy particles can be used.

  The average particle diameter of the aluminum-based particles is preferably about 1 to 100 μm. If the average particle size is less than 1 μm, it is unsuitable in terms of handleability. On the other hand, when it exceeds 100 μm, the specific surface area becomes small, and it is better to avoid it in terms of oxygen absorption capacity. Further, the shape of the aluminum-based particles is not limited, and may be any of spherical shape, spheroid shape, indefinite shape, teardrop shape, flat shape, and the like.

  The resin component (polymer) coated on the surface of the aluminum-based particles is preferably a copolymer obtained by reacting at least two oligomers and monomers having at least one polymerizable double bond. The amount of each oligomer or monomer used can be arbitrarily set.

  The oligomer or monomer constituting the polymer is not particularly limited as long as it has at least one polymerizable double bond.

  Examples of the monomer having at least one polymerizable double bond include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, citraconic acid, maleic acid or maleic anhydride), and nitriles thereof (for example, acrylonitrile). Or methacrylonitrile) or an ester thereof (for example, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, hydroxyethyl acrylate, acrylic acid 2) -Hydroxypropyl, methoxyethyl acrylate, butoxyethyl acrylate, glycidyl acrylate, cyclohexyl acrylate, 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate, trimethylo Propanetriacrylate, tetramethylol methane tetraacrylate, tetramethylol methane triacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, methacryl Acid hydroxyethyl, 2-hydroxypropyl methacrylate, methoxyethyl methacrylate, butoxyethyl methacrylate, glycidyl methacrylate, cyclohexyl methacrylate, trimethylolpropane trimethacrylate, or tetramethylolmethane trimethacrylate). In addition, a cyclic unsaturated compound (for example, cyclohexene) or an acyclic unsaturated compound (for example, styrene, α-methylstyrene, vinyl toluene, divinylbenzene, cyclohexene vinyl monoxide, divinylbenzene monooxide, vinyl acetate, vinyl propionate or Examples thereof include diallylbenzene).

  For example, if divinylbenzene, allylbenzene, diallylbenzene or a mixture thereof is used as a monomer having at least two polymerizable double bonds, the stability is further improved by the crosslinking action (it can be coated with a more stable film). The use of monomers having at least two ionic double bonds is particularly preferred.

  Examples of the oligomer having at least one polymerizable double bond include epoxidized 1,2-polybutadiene, acrylic-modified polyester, acrylic-modified polyether, acrylic-modified urethane, acrylic-modified epoxy, and acrylic-modified spirane (all having a polymerization degree of 2 ˜about 20). Among these, at least one of epoxidized 1,2-polybutadiene and acrylic modified polyester is preferable. The degree of polymerization is preferably about 3 to 10. The use of an oligomer makes the reaction efficiency very high because the polymerization reaction proceeds gradually, and is preferable to the case where the monomer is used alone.

  The method for coating aluminum particles is not particularly limited. For example, 1) a method of impregnating or immersing aluminum-based particles in a solution or dispersion obtained by dissolving or dispersing a resin component in a solvent, and then drying to coat the resin component on the particle surface; 2) After preparing a solution or dispersion containing a monomer or oligomer capable of constituting a predetermined resin component and a mixed solution containing aluminum-based particles, the monomer or oligomer is polymerized to form particles of the polymer (resin component). For example, a method of coating the surface.

  In particular, in the present invention, the method 2) can be suitably employed. As this method, for example, after preparing a dispersion liquid in which aluminum-based particles are dispersed in an organic solvent, at least two kinds of oligomers and monomers having at least one polymerizable double bond are dissolved in the dispersion liquid. Then, the copolymer can be coated on the particle surface by heating in the presence of a polymerization initiator.

  Examples of the organic solvent include aliphatic hydrocarbons such as hexane, heptane, octane, cyclohexane, and mineral spirits, aromatic hydrocarbons such as benzene, toluene, and xylene, chlorobenzene, trichlorobenzene, perchlorethylene, and trichlorobenzene. Halogenated hydrocarbons such as methanol, ethanol, n-propatool, n-butanol and the like, ketones such as 2-propanone and 2-butanone, esters such as ethyl acetate and propyl acetate, tetrahydrofuran, diethyl Examples include ether and ethylpropyl ether.

  The polymerization initiator may be a known high or medium temperature polymerization initiator such as di-t-butyl peroxide, acetyl peroxide, benzoyl peroxide, lauroyl peroxide, cumyl hydroperoxide, t-butyl hydroperoxide, An azo compound such as α, α'-azobisisobutyronitrile can be used.

  The polymerization reaction temperature (heating temperature) is not limited, and can generally be appropriately set within a range of 60 to 200 ° C.

  Moreover, in this invention, a polymerization reaction can also be performed in inert gas atmosphere, such as nitrogen, helium, argon, etc. for the purpose of improving superposition | polymerization efficiency as needed.

  The resin-coated Al-based particles produced as described above may be recovered using a known solid-liquid separation method, purification method, or the like as necessary.

  In the present invention, when aluminum-based particles are used as a main agent, it is preferable to use aluminum compound particles as an auxiliary agent. Examples of the aluminum compound include at least one of alumina (aluminum oxide), aluminum hydroxide, aluminate, aluminosilicate, and the like. Among these, it is particularly preferable to use alumina. By using alumina particles, effective oxygen absorption performance can be expressed by its catalytic action.

  The ratio between the aluminum-based particles and the auxiliary agent is not particularly limited, but is preferably 3: 7 to 7: 3 by mass ratio.

  Further, if necessary, an electrolyte may be added to effectively promote the oxygen absorption action of the aluminum-based particles. As the electrolyte, for example, at least one of calcium oxide, calcium hydroxide, magnesium oxide, magnesium hydroxide, sodium chloride, potassium chloride, calcium chloride, sodium carbonate, calcium carbonate and the like can be added in an appropriate amount as necessary.

  In addition, there is a possibility that hydrogen is generated as a side reaction when oxygen is absorbed by the aluminum-based particles. In this case, hydrogen generation inhibitors such as silver oxide, titanium, zeolite, activated carbon, and sulfide are required in the oxygen absorbent. Accordingly, it can be added within a range of 1 ppm to 10% by mass.

  Furthermore, in order to make the oxygen absorption reaction of the aluminum-based particles easier, water can be contained in the oxygen absorbent in an amount of 5 to 85% by mass as necessary.

2. Packaging Material Production Method The packaging material of the present invention is, for example, a method for producing a packaging material comprising a laminate having at least a base material layer and a thermal adhesive layer, and has an average primary particle diameter of 3 on the surface of the thermal adhesive layer. It can be suitably obtained by a method for producing a packaging material including a step of attaching hydrophobic oxide fine particles of ˜100 nm (hereinafter also referred to as “attachment step”).

  The laminate itself can be produced according to a known method. For example, with respect to a laminated material produced by a single layer base material or a dry laminating method, an extrusion laminating method, a wet laminating method, a heat laminating method, etc. A thermal adhesive layer may be formed by the method described in (1).

  Further, the oxygen absorbent is the same as in the above 1. Those described in the above can be used. As described above, these may be contained in advance in the raw material for forming the base material layer and / or the thermal adhesive layer.

  The method for carrying out the step of attaching the hydrophobic oxide fine particles is not particularly limited. For example, known methods such as roll coating, gravure coating, bar coating, doctor blade coating, brush coating, and electrostatic powder method can be employed. When roll coating or the like is employed, the adhesion step can be carried out by a method of forming a coating film on the thermal adhesive layer using a dispersion obtained by dispersing hydrophobic oxide fine particles in a solvent and then drying. The solvent in this case is not limited, and in addition to water, for example, alcohol (ethanol), cyclohexane, toluene, acetone IPA, propylene glycol, hexylene glycol, butyl diglycol, pentamethylene glycol, normal pentane, normal hexane, hexyl alcohol, etc. The organic solvent can be appropriately selected. At this time, a very small amount of a dispersant, a colorant, an anti-settling agent, a viscosity modifier and the like can be used in combination. The dispersion amount of the hydrophobic oxide fine particles with respect to the solvent is usually about 10 to 100 g / L. When drying, either natural drying or forced drying (heat drying) may be used, but industrially forced drying is preferable. The drying temperature is not limited as long as it does not affect the thermal adhesive layer, but is usually 150 ° C. or less, and preferably 80 to 120 ° C.

  In the manufacturing method of this invention, a laminated body can also be heated during the said adhesion process and / or after an adhesion process. By heating the laminate, the adhesion (fixing force) of the hydrophobic oxide fine particles to the thermal adhesive layer can be further increased. The heating temperature T in this case can be set as appropriate according to the type of the thermal adhesive layer and the like, and usually Tm−50 ≦ T ≦ Tm + 50 with respect to the melting point Tm (melting start temperature) ° C. of the thermal adhesive layer used. It is preferable to be in the range. Further, the packaging material of the present invention may be subjected to embossing, half-cutting, notching, etc., as necessary, similarly to known packaging materials.

  The features of the present invention will be described more specifically with reference to the following examples and comparative examples. However, the scope of the present invention is not limited to the examples.

Examples 1 to 3 and Comparative Example 1
Samples were prepared and evaluated as follows.

(1) Preparation of thermal adhesive (1-1) Thermal adhesive containing iron-based oxygen absorber The iron-based oxygen absorber is a heat-sealed product using a commercial product (“AGELESS” manufactured by Mitsubishi Gas Chemical Co., Ltd.) as it is. 10% by weight of lacquer (main component: 160 parts by weight of a polyester resin + 10 parts by weight of an acrylic resin + 40 parts by weight of a solvent (a mixed solvent of toluene and MEK)) was added and mixed to obtain the thermal adhesive of Example 1.
(1-2) Thermal Adhesive Containing Aluminum Oxygen Absorbent The main component of the aluminum oxygen absorbent is pure aluminum powder (atomized powder manufactured by Toyo Aluminum Co., Ltd., average particle size: 8 μm, BET specific surface area 0.7 m ^2. / G) and resin-coated aluminum powder (resin coating amount 3 g / 100 g aluminum content) whose resin was coated on the surface of the aluminum powder. The method of coating the surface of the aluminum powder with a resin is as follows. A fourth flask having a volume of 3 liters was epoxidized 1,2-polybutadiene: 1.5 g, trimethylolpropane triacrylate: 3.5 g, acrylic acid: 0.3 g, Divinylbenzene: 1.4 g, mineral spirit: 1440 g, untreated aluminum powder: 200 g were charged and sufficiently stirred and mixed while introducing nitrogen gas. The temperature in the system was raised to 80 ° C., 1.1 g of α, α′-azobisisobutyronitrile (AIBN) was added, and the mixture was reacted at 80 ° C. for 6 hours while stirring was continued. After completion of the reaction, the mixed solution was filtered and dried at 140 ° C. to obtain a resin-coated aluminum powder.
Next, 1 g of the main component of the aluminum-based oxygen absorbent, 1 g of α-alumina powder (TM-DAR, manufactured by Daimei Chemical Co., Ltd., average particle size 0.1 μm, BET specific surface area 14.5 m ² / g), calcium oxide (sum Stirring and mixing 0.5 g of Kojun Pure Co., Ltd. (purity 99.9%) and 0.5 g of zeolite A-4 (manufactured by Wako Pure Chemical Industries, Ltd., average particle size 3.5 μm), followed by binder (main component: 27 parts of polyester resin 160 parts by weight + acrylic resin 10 parts by weight + solvent (toluene + MEK mixed solvent) 40 parts by weight) and mixed with stirring, and 1 g of water is added and mixed. A thermal adhesive was used.

(2) Production of packaging materials
Using a polyurethane dry laminate adhesive (weight after drying: 3.5 g / m ² ; abbreviated as D) on one side of a 15 μm thick aluminum foil (1N30, soft foil; abbreviated as AL), back printing (abbreviated as printing) The substrate was bonded to the printed surface of a 12 μm thick polyethylene terephthalate film (abbreviated as PET). A separately prepared polyethylene terephthalate film (abbreviated as PET) having a thickness of 12 μm was bonded to the aluminum surface of the base material layer using a polyurethane dry laminate adhesive (weight after drying: 3.5 g / m ² ; abbreviated as D). In addition, each of the thermal adhesives prepared in (1-1) and (1-2) was applied to a weight of 3 g / m ² after drying.
In addition, as Comparative Example 1, a thermal adhesive not containing an oxygen absorbent (main component: 160 parts by weight of a polyester resin + 10 parts by weight of an acrylic resin + 40 parts by weight of a solvent (a mixed solvent of toluene + MEK)) was used. Produced a packaging material in the same manner as described above.

(3) Adhesion of hydrophobic oxide fine particles 5 g of hydrophobic oxide fine particles (product name “AEROSIL R812S” manufactured by Evonik Degussa, BET specific surface area: 220 m ² / g, primary particle average diameter: 7 nm) are dispersed in 100 mL of ethanol. A coating solution was prepared. This coating solution is applied to the surface of the thermal adhesive layer of the packaging material prepared in (2) above by a bar coating method so that the weight after drying is 0.5 g / m ^2, and then at 100 ° C. for about 10 seconds. The sample was obtained by drying and evaporating the ethanol. In addition, hydrophobic oxide fine particles are not attached to the sample of Comparative Example 1.

(4) Observation of porous layer made of hydrophobic oxide fine particles In the packaging material of each example, the structure of the layer made of hydrophobic oxide fine particles was observed by FE-SEM. As a result, a porous layer having a three-dimensional network structure formed of hydrophobic oxide fine particles was observed for any packaging material.

(5) Measurement of residual oxygen in container A package was prepared using a lid material obtained by cutting out each sample into a lid material shape (rectangular length of 62 mm × width of 67 mm). Specifically, 80 g of water was filled in a flanged polystyrene container (formed with a flange width of 4 mm, a flange outer diameter of 60 mm × 65 mm □, a height of about 48 mm, and an internal volume of about 105 cm ³ ). Each package was produced by heat-sealing the lid on the flange. The heat seal condition was a ring (concave) seal having a width of about 2 mm per ^second at a temperature of 220 ° C. and a pressure of 3 kgf / cm ² . After standing at room temperature for 72 hours, the residual oxygen concentration in the container was measured with an apparatus “OXYGEN ANALYZER (LC-750 manufactured by TORAY)”. The results are shown in Table 1.

(6) Amount of residual air (gas) in the container Open the lid of the sample in the water tank for the package produced in the same manner as in (5) above, and collect the air (gas) coming out of the container with a measuring cylinder. The amount of gas was measured in water. The results are shown in Table 1.

(7) Non-adhesive and scattering properties of yogurt A package is prepared in the same manner as in (5) above except that the content is a commercially available yogurt (product name “Delicious Caspian Sea” soft yogurt, manufactured by Glico Dairy Co., Ltd.) And after leaving in a refrigerator set at 5 ° C. for 72 hours, tilt the container upside down (the container lid side is the ground direction) and then return to the original state (the container lid side is the top direction) This was repeated three times and the lid was opened. For the evaluation of non-adhesiveness, the state of the lid was visually observed, and the case where yogurt was adhered was defined as “failed” and the state where yogurt was not adhered was defined as “accepted”. In addition, as evaluation of the scattering property, when the lid was opened, the yogurt liquid droplets that had jumped out of the container were determined to be “failed”, and those that did not fly were determined to be “passed”. The results are shown in Table 1.

(8) Contact angle The contact angle measurement device (solid-liquid interface analyzer “Drop Master 300” manufactured by Kyowa Interface Science Co., Ltd.) was used to measure the contact angle of pure water using the thermal adhesive layer side of each packaging material as the test surface. . The results are shown in Table 1.

  As is clear from the results in Table 1, the non-adhesive property is not exhibited at all in the conventional product (comparative example), whereas the high non-adhesive property is exhibited in the present invention (example). . Moreover, it turns out that the packaging material of this invention shows high non-adhesiveness also from the result of a contact angle.

  In particular, the outermost surface on the thermal adhesive layer side of the packaging material of the present invention (the surface on which hydrophobic oxide fine particles are adhered) has a contact angle of pure water of 150 degrees or more, which is superior to conventional packaging materials. It has non-adhesive contents. Furthermore, since the lid material of the present invention contains an oxygen absorbent in at least one of the base material layer and the thermal adhesive layer, in addition to being effective for long-term storage by preventing spoilage and deterioration, the pressure in the package is reduced. It can be seen that the reduction is effective in preventing the contents from being scattered and ejected.

Claims (8)

A lid member comprising a laminate having at least a base material layer and a thermal adhesive layer, wherein the thermal adhesive layer is laminated as an outermost layer on one surface of the lid material , and at least the base material layer and the thermal adhesive layer Hydrophobic oxide fine particles having an average primary particle diameter of 3 to 100 nm are attached to the outermost surface that contains an oxygen absorbent on one side and the thermal adhesive layer is not adjacent to other layers, and the hydrophobic oxide fine particles are in a three-dimensional network. Forming a porous layer of a structure, filled with contents in a container, and sealed in a state in which the opening and the thermal adhesive layer of the lid are in contact with each other,
A lid material in which hydrophobic oxide fine particles existing on a region to be thermally bonded are embedded in the thermal bonding layer at the time of thermal bonding . The lid | cover material of Claim 1 whose adhesion amount of hydrophobic oxide microparticles | fine-particles is 0.01-10 g / m < ² >. The lid | cover material of Claim 1 or 2 whose contents are fermentable food-drinks . The lid | cover material in any one of Claims 1-3 whose specific surface area by BET method of hydrophobic oxide microparticles | fine-particles is 50-300 m < ² > / g. The lid | cover material in any one of Claims 1-4 whose hydrophobic oxide microparticles | fine-particles are hydrophobic silica. The lid material according to claim 5, wherein the hydrophobic silica has a trimethylsilyl group on the surface thereof. The lid | cover material in any one of Claims 1-6 in which the said oxygen absorber contains the metal particle by which at least 1 sort (s) of the resin component and the inorganic oxide were coat | covered by the at least one part of particle | grain surface. The lid | cover material in any one of Claims 1-7 used for the product in which the said content is packaged with the lid | cover material and the container in the state which can contact the content with the outermost surface by the side of a heat bonding layer.