JP2007245492A - Heat resistant paper container having light shielding properties - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper container which prevents a deterioration in contents etc. , by giving light shielding properties and heat resistance to the packaging material of the paper container for milk, juice, coffee, alcoholic beverages, etc. , simplifies the lamination structure of the packaging material without spoiling the light shielding properties, and is excellent in heat resistance, storage properties, and appearance designability. <P>SOLUTION: In the paper container obtained by box making by laminating a light shielding resin layer, an adhesive resin layer, and a thermoplastic resin layer in turn on the inner surface of a paper substrate layer and using a lamination material obtained by laminating/constituting a thermoplastic resin layer on the outer surface of the paper substrate layer, the light shielding resin layer contains titanium dioxide (which is) at least 0.1 μm in particle size and titanium dioxide (which is) 0.1 μm or below in particle size. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to paper containers for milk, juice, coffee beverages, alcoholic beverages, etc., and more specifically, by imparting light shielding properties and heat resistance to the packaging material, preventing alteration of the contents, etc., heat resistance, The present invention relates to a paper container excellent in preservability and appearance design.

  2. Description of the Related Art Conventionally, paper containers for filling and packaging liquid foods and drinks such as milk, juice and coffee drinks, mineral water, liquid seasonings, and alcoholic beverages have been developed and proposed. Among these, milk, juice, coffee drinks, alcoholic beverages, and the like are known to be easily affected by light and ultraviolet rays, deteriorate due to oxidation and the like, and cause deterioration in quality such as sensuality. Normally, the contents filled and packaged in a paper-based liquid container have a certain amount of light shielding properties depending on the paper layer portion of the packaging material, but in an environment where they are stored for a long period of time. Fluorescent lamp light and slight ultraviolet light are thought to cause deterioration of the contents, and packaging materials with laminated aluminum foil were used as containers for paper liquids that give further light shielding properties to packaging materials . However, a paper liquid container made of a packaging material in which the aluminum foil is laminated has a problem of waste disposal due to ash-like residue during incineration, and when not incinerated, the aluminum foil is separated and paper is not incinerated. It was not easy to recover the resin.

Further, as a light shielding packaging material instead of the packaging material laminated with the aluminum foil, a container packaging material was used in which a pigment such as carbon black was mixed with a synthetic resin and a colored resin layer provided with light shielding properties was laminated. A paper container has been proposed in which a paper liquid container provides the same light shielding property as a packaging material including the above-described aluminum foil, and has an effect that no residue is generated during incineration during disposal (for example, a patent) Reference 1).
JP-A-6-122444

  The paper liquid container described in the above-mentioned patent document is provided with a plastic layer as an innermost layer and an outermost layer of paperboard, which is a base material, and excellent in thermal conductivity between the base material and the innermost layer as a configuration of the laminated material. In addition, a laminated structure provided with a colored plastic layer added with an inorganic substance is shown, and the colored plastic layer is made of plastic such as low density polyethylene, high density polyethylene, polyester, nylon, carbon black, titanium oxide, metal powder, mica. In the case of carbon black, the addition amount is suitably 2 to 40% by weight, in the case of titanium oxide, the range of 1.5 to 15% by weight is appropriate, and the thickness is 10 to 20 μm. It has been shown that the goal can be fully achieved.

In addition, a colored plastic layer, that is, a colored resin layer mixed with a pigment such as carbon black, is disposed on the outer surface side of the base paperboard to avoid contact with the contents, and to avoid contact between the conventional colored resin layer and the contents There has also been proposed a structure in which the layer structure of the container and packaging material is simplified by omitting the synthetic resin layer (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 2000-238761

However, since the paper liquid container shown in Patent Document 1 is composed of a pigmented material such as carbon black mixed with a colored plastic layer laminated on the inner layer of paperboard as a base material, the plastic layer is the innermost layer. Direct contact between the colored plastic layer and the contents is avoided, but the appearance at the time of opening is not good, and because of the odor peculiar to carbon black, the taste of foods that are sensitive to chemical agents (such as milk) It is not preferable from the influence on etc.
Further, in the paper liquid container shown in Patent Document 2, since a colored resin layer is provided on the outer surface side of the paperboard, a synthetic resin layer for avoiding contact with contents is omitted, but a colored resin is used to improve the appearance. A synthetic resin layer containing a white pigment is provided on the outer surface side of the layer, resulting in a complicated layer structure and a complicated manufacturing process for the packaging material.

  Accordingly, an object of the present invention is to solve the above-mentioned problem, and in a packaging material for preventing alteration of contents in a paper container such as milk, juice, coffee drink, and liquor. The light-blocking resin layer does not use colored pigments such as carbon black, simplifies the laminated structure of the packaging material without impairing light-blocking properties, and also has excellent light-blocking properties with excellent heat resistance, storage stability, and appearance design. It is providing the heat-resistant paper container which has this.

  In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that a light shielding resin layer, an adhesive resin layer, and a thermoplastic resin layer are sequentially laminated on the inner surface of the paper base layer, and the outer surface of the paper base layer is formed. In a paper container formed by using a laminated material in which a thermoplastic resin layer is laminated, the light shielding resin layer contains both titanium dioxide having a particle diameter of 0.1 μm or more and titanium dioxide having a particle diameter of 0.1 μm or less. This is a paper container.

  The invention according to claim 2 is the paper container according to claim 1, wherein a thermoplastic resin layer and an adhesive resin layer are sequentially laminated between the paper base material layer and the light shielding resin layer.

  A third aspect of the present invention is the paper container according to the first and second aspects, wherein the light shielding resin layer is made of polyamide.

  Since the heat-resistant paper container having light shielding properties according to the present invention uses titanium dioxide as the light shielding layer, even if a light shielding resin layer is laminated on the inner surface of the paper base material layer of the packaging material, for example, milk or the like There is an effect that there is no possibility that the contents sensitive to chemical agents will be altered and the taste will not be affected.

  Further, in addition to the configuration in which the light base resin layer, the adhesive resin layer, and the thermoplastic resin layer are directly provided on the inner surface of the paper base layer, a thermoplastic resin is provided between the paper base layer and the light masking resin layer. By forming a laminated structure of three types and five layers of a resin layer, a thermoplastic resin layer to which an adhesive resin layer is added, an adhesive resin layer, a light shielding resin layer, an adhesive resin layer, and a thermoplastic resin layer, the paper base There is an effect that the adhesion between the material layer and the light shielding resin layer is further improved.

  Further, by using titanium dioxide having a different particle diameter for the light-shielding resin layer, it is possible to conceal light having different wavelengths. That is, titanium dioxide having a particle size of 0.1 μm or more has a large refractive index and particularly high visible light blocking properties, and titanium dioxide having a particle size of 0.1 μm or less, particularly in the range of 0.01 to 0.1 μm Particularly, since both have excellent ultraviolet light blocking properties, using both simultaneously has the effect of concealing visible light to ultraviolet light simultaneously. Furthermore, since colored pigments, such as carbon black, are not comprised, there exists an effect that it is excellent in the designability of the inner surface of a packaging material.

  Furthermore, in the present invention, since the light shielding resin layer is made by adding titanium dioxide to a polyamide resin such as nylon, a packaging material having excellent heat resistance can be obtained, and the packaging material is used. In producing a paper container, when heat-sealing with hot air or the like, there is an effect of resisting heating by hot air and preventing the occurrence of pinholes and the like.

  The present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a laminated structure of a heat-resistant paper container packaging material having light blocking properties according to the present invention. FIG. 2 is a schematic cross-sectional view showing an example of a laminated structure of a heat-resistant paper container packaging material having light blocking properties according to the present invention. FIG. 3 is a perspective view showing the paper container after filling the contents manufactured using the packaging material for heat-resistant paper containers having light blocking properties according to the present invention.

  First, as shown in FIG. 1, the laminated structure of the packaging material A that constitutes the heat-resistant paper container having light blocking properties according to the present invention is the thermoplastic resin layer 1 and the paper from the container outer surface side toward the container inner surface side. The substrate layer 2, the light shielding resin layer 3, the adhesive resin layer 4, and the thermoplastic resin layer 5 are sequentially laminated, and more specifically, have the light blocking property according to the present invention. As shown in FIG. 2, as a packaging material A ′ constituting a heat-resistant paper container, a thermoplastic resin layer 1, a paper base material layer 2, a thermoplastic resin layer 6, an adhesive resin layer 7, a light shielding resin layer 3, an adhesive In this structure, the thermoplastic resin layer 4 and the thermoplastic resin layer 5 are sequentially laminated.

  Next, as an example of the heat-resistant paper container having light shielding properties according to the present invention manufactured by using the above-described packaging material, first, as shown in FIG. Then, a blank plate for paper container having a predetermined shape subjected to ruled line processing or the like is punched out, and then the body edge of the blank plate is overlapped, and the overlapping end is welded to form the cylindrical body 10. Next, in the present invention, the cylindrical body 10 formed as described above is attached to a filling and packaging machine, and the bottom part is folded and heat-sealed using a predetermined ruled line to form the bottom part 11, The top is filled with the contents from the open top, and then the top is folded and heat-sealed using a predetermined ruled line to form a roof-type top 12 having a joint portion as shown in the figure. Thus, the heat-resistant paper container product B having light blocking properties according to the present invention is manufactured. The above production example shows an example of a heat-resistant paper container having light shielding properties according to the present invention, and is not limited to this, and the light shielding properties according to the present invention shown in FIG. 2 described above. As in the above production example, the heat-resistant paper container having light blocking properties according to the present invention can be produced using the packaging material A ′ constituting the heat-resistant paper container having the above. Further, in the present invention, the shape of the paper container to be formed can be any desired shape in addition to the above-mentioned gobeltop shape. For example, a so-called brick top shape paper container having a flat top is also produced. can do.

  In the present invention, the packaging material constituting the heat-shielding paper container having light shielding properties according to the present invention as described above, and the heat-resistant paper container having light shielding properties according to the present invention manufactured using the packaging material are constructed. When materials are described, various materials can be used as such materials.

First, as the thermoplastic resin constituting the thermoplastic resin layer of the packaging material, the same resin can be used, for example, a polyolefin resin having various heat sealing properties that can be melted by heat and fused to each other. In particular, for example, low density polyethylene, medium density polyethylene, high density polyethylene, linear (linear) low density polyethylene, ethylene polymerized using a metallocene catalyst α-olefin copolymer, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer Polymers such as coalesce, methylpentene polymer, polybutene polymer, polyethylene or polypropylene Olefin resins modified with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, acid-modified polyolefin resin, polyvinyl acetate resin, poly (meth) acrylic resin, Polyvinyl chloride resin and other resins can be used.
In the present invention, one or two or more of the above resins are used and melt extruded or coextruded using an extruder or the like, and the thermoplastic resin layer is laminated, or the above One or two or more of such resins are used in advance, and a resin film or sheet is produced in advance, and the film or sheet is dry-laminated and laminated via an adhesive for lamination, etc. The layers are laminated. In the present invention, the thickness of the outermost layer or the innermost layer of the thermoplastic resin layer is in the range of 5 to 200 μm, preferably in the range of 10 to 100 μm.

Next, as the paper base material that constitutes the paper base material layer of the packaging material, since it becomes the basic material that constitutes the paper container, a material having saddle characteristics, flex resistance, rigidity, waist, strength, etc. is used. For example, various sized paper substrates such as a strongly sized bleached or unbleached paper substrate, or pure white roll paper, kraft paper, paperboard, processed paper, etc. can be used.
In the present invention, as the paper substrate, those having a basis weight in the range of about 80 to 600 g / m ² , preferably in the range of the basis weight of 100 to 450 g / m ² can be used. In the present invention, a desired printed picture such as a character, a figure, a picture, a symbol, or the like can be arbitrarily formed on the paper base by a normal printing method.

Next, as the adhesive resin constituting the adhesive resin layer of the packaging material, the light concealing layer and the thermoplastic resin layer are respectively closely bonded, and the same one can be used, for example, by heat Various heat-sealable polyolefin-based resins that can be melted and fused to each other, and the like can be used. Specifically, for example, the same thermoplastic resin that constitutes the thermoplastic resin layer described above, for example, , Low density polyethylene, medium density polyethylene, high density polyethylene, linear (linear) low density polyethylene, ethylene-α-olefin copolymer polymerized using metallocene catalyst, polypropylene, ethylene-vinyl acetate copolymer , Ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene -An acid obtained by modifying a polyolefin resin such as propylene copolymer, methylpentene polymer, polybutene polymer, polyethylene or polypropylene with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid or itaconic acid. Modified polyolefin resins, polyvinyl acetate resins, poly (meth) acrylic resins, polyvinyl chloride resins, and other resins can be used.
In the present invention, one or more of the above resins are used, and this is used, for example, by using an extruder or the like, between the light hiding layer and the thermoplastic resin layer, and anchors if necessary. The light-shielding layer and the thermoplastic resin layer are extrusion laminated while being melt-extruded into a single layer or multiple layers via a coating agent layer to form an adhesive resin layer. In the above, as thickness of adhesive resin layers, such as polyolefin resin, the range of 3 micrometers-50 micrometers, and also 5 micrometers-35 micrometers are preferable.

Next, as the resin constituting the light shielding layer of the packaging material, since titanium dioxide is included in this, it has excellent properties in mechanical, physical, chemical, etc., and particularly has strength. And tough and heat resistant resin, film or sheet can be used. Specifically, for example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, fluorine resin, polystyrene resin. , Acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, poly (meth) acrylic resin, polycarbonate resin, polyethylene terephthalate, polyethylene naphthalate Polyester resins such as phthalates, various polyamide resins such as nylon, polyimid Resin, polyamideimide resin, polyarylphthalate resin, silicone resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyurethane resin, acetal resin, cellulose resin, etc. Resin, film or sheet can be used. In addition, in this invention, it is preferable to consist of polyamide-type resin, such as nylon excellent in heat resistance.
In the present invention, as the above various resins, films or sheets, for example, one or more of the above various resins are used, extrusion method, cast molding method, T-die method, cutting method, inflation method, etc. A method of forming the above-mentioned various resins alone using a film-forming method such as, or a method of forming a multilayer coextrusion film using two or more types of resins, Using two or more kinds of resins, various resin films or sheets are manufactured by a method of mixing and forming before forming a film, and if necessary, a tenter method or a tubular method. Etc., various resin films or sheets obtained by stretching in a uniaxial or biaxial direction can be used. In the present invention, various resin films or sheets have a film thickness in the range of 5 to 50 μm, and more preferably in the range of 9 to 20 μm.

  The light-shielding resin layer is composed of the above-described various resins, specifically, polyamide resins such as nylon, titanium dioxide having different particle diameters, specifically, titanium dioxide having a particle diameter of 0.1 μm or more, and a particle diameter. It is constituted by containing titanium dioxide of 0.1 or less. Titanium dioxide has a different wavelength of light to conceal depending on the particle diameter. For example, the particle diameter used in the present invention is 0.1 μm or more. Titanium dioxide has a large refractive index and particularly high visible light blocking properties, while titanium dioxide having a particle diameter of 0.1 μm or less and in the range of 0.01 to 0.1 μm has particularly ultraviolet light blocking properties. Since it is high, if the titanium dioxides having different particle diameters are mixed together, it is possible to obtain a light shielding resin layer capable of simultaneously concealing the range from visible light to ultraviolet light. In addition, the light-shielding resin layer does not contain a colored pigment such as carbon black in the laminated structure, and the titanium dioxide contained is a colorless and transparent fine particle, but appears white by irregularly reflecting light rays. Presents the design of the inner surface of the packaging material.

  Furthermore, in this invention, since the structure of a light-shielding resin layer contains titanium dioxide in polyamide resins, such as nylon, the structure excellent in heat resistance can be obtained, and it has the light-shielding property which concerns on this invention In manufacturing a paper container using a packaging material that constitutes a heat-resistant paper container, when heat-sealing with hot air or the like, it is resistant to heating with hot air and prevents the occurrence of pinholes, etc. Since the polyamide-based resin has heat resistance and alkali resistance, a paper container suitable for filling and packaging of alkaline contents can be manufactured.

  It should be noted that one or more of the above-mentioned various resins are used, and in forming the film, for example, film processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness Various plastic compounding agents and additives can be added for the purpose of improving and modifying mold release properties, flame retardancy, antifungal properties, electrical properties, strength, etc. Can be arbitrarily added from a very small amount to several tens of percent depending on the purpose. In the above, as a general additive, for example, a lubricant, a crosslinking agent, an antioxidant, a filler, an antistatic agent, an antiblocking agent, and the like can be used.

  Next, in the present invention, as a method for producing a laminated material using the resin and materials as described above, a method for laminating a normal packaging material, for example, a wet lamination method, a dry lamination method, a solventless dry lamination is used. It can be performed by a method, an extrusion lamination method, a T-die coextrusion molding method, a coextrusion lamination method, an inflation method, or the like. Furthermore, in the present invention, when performing the above-mentioned lamination, for example, pretreatment such as corona treatment and ozone treatment can be applied to a film or the like, if necessary, for example, isocyanate (urethane), polyethylene Anchor anchors such as imine, polybutadiene, and organic titanium, or known anchors such as polyurethane, polyacrylic, polyester, epoxy, polyvinyl acetate, cellulose, and other adhesives for laminating A coating agent, an adhesive, etc. can be used.

  In the present invention, the paper container produced as described above is suitable for filling and packaging various articles. For example, beverages such as milk, dairy products, juices, alcoholic beverages, coffee, teas, seasonings, soups, etc. It can be used for filling and packaging of foodstuffs, chemicals such as adhesives, pressure-sensitive adhesives, agricultural chemicals and insecticides, pharmaceuticals, cosmetics, shampoos, rinses, detergents and other miscellaneous goods, etc. .

The above-described present invention will be specifically described with reference to examples.
[Example]
A light shielding layer was prepared by kneading 3% by weight of titanium dioxide having a particle diameter of 0.6 μm and 2% by weight of titanium dioxide having a particle diameter of 0.05 μm into 6-nylon as a polyamide. The actual laminated structure consists of a thermoplastic resin layer, low density polyethylene (Mirason 16P, manufactured by Mitsui Chemicals, Inc., trade name) 20 μm / paper substrate layer / paperboard (basis weight 320 g / m ² ) / light-shielding resin from the outer surface of the container. 6-nylon (UBE nylon 1022B, Ube Industries, trade name) 20 μm / adhesive resin layer (Admer LB548, Mitsui Chemicals, trade name) 10 μm / low density polyethylene (Mirason 16P, Mitsui Chemicals) Company name, product name) 30 μm. As a method of laminating, a packaging material was manufactured using tandem coextrusion lamination.
Using the packaging material having the above-described laminated structure, a 500 ml gable top type paper container was manufactured.

[Comparative example]
In the above example, titanium dioxide was not kneaded into 6-nylon (20 μm), and a packaging material was manufactured. Similarly to the above example, a Gobeltop type paper container having an internal volume of 500 ml was manufactured.

[Experimental example]
Each paper container manufactured in the above examples and comparative examples is filled and packaged with 500 ml of milk and stored for one week under normal fluorescent light exposure conditions in a chilled environment of about 6 degrees Celsius. Sensory evaluation of the thing (milk) was performed.

As a result of the above experimental example, flavor deterioration did not occur in the examples, and flavor deterioration was clearly recognized in the comparative example.
In the Example using the paper container formed from the packaging material which laminated | stacked the light hiding resin layer, there was no deterioration of the milk of the content without being influenced by light and an ultraviolet-ray, and the taste did not fall after storage. On the other hand, in the comparative example in which titanium dioxide was laminated without being kneaded into the light-shielding resin layer, the content milk deteriorated under the influence of light and ultraviolet rays, and the taste after storage decreased.

The schematic sectional drawing which shows an example of the laminated structure of the packaging material for heat-resistant paper containers which has the light-shielding property which concerns on this invention. The schematic sectional drawing which shows an example of the laminated structure of the packaging material for heat-resistant paper containers which has the light-shielding property which similarly concerns on this invention. The perspective view which shows the paper container after the content filling manufactured using the packaging material for heat-resistant paper containers which has the light-shielding property which concerns on this invention.

Explanation of symbols

A, A ′ Packaging material constituting a paper container 1 Thermoplastic resin layer 2 Paper base material layer 3 Light concealment resin layer 4 Adhesive resin layer 5 Thermoplastic resin layer 6 Thermoplastic resin layer 7 Adhesive resin layer 10 Cylindrical body Part 11 Bottom 12 Top

Claims (3)

A light shielding resin layer, an adhesive resin layer, and a thermoplastic resin layer are sequentially laminated on the inner surface of the paper base material layer, and a box is formed using a laminate material in which the thermoplastic resin layer is laminated on the outer surface of the paper base material layer. In this paper container, the light shielding resin layer contains both titanium dioxide having a particle diameter of 0.1 μm or more and titanium dioxide having a particle diameter of 0.1 μm or less. 2. The paper container according to claim 1, wherein a thermoplastic resin layer and an adhesive resin layer are sequentially laminated between the paper base material layer and the light shielding resin layer. The paper container according to claim 1 or 2, wherein the light shielding resin layer is made of polyamide.

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