JPH09301353A - Paper container for liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper container which is excellent in barrier property for oxygen and water vapor etc., and in addition, is good is heat resistance, and has a filling-packaging compatibility for the content, is excellent in the keeping quality, and can correspond with the environment by constituting the paper container of a laminated material including a resin layer of crystalline aromatic polyamide based resin, between the innermost layer and a supporting body. SOLUTION: For a laminated material A to be constituted, from the inside to the outside, a heat-sealable resin layer 1, a bondable resin layer 2 which is provided when necessary, a resin layer 3 of a crystalline aromatic polyamide based resin, an adhesive layer 4, a supporting body 5 of which the major component is paper, and a heat- sealable resin layer 1' are laminated in order. As the crystalline aromatic polyamide based resin, e.g. an aromatic crystalline polyamide based resin which is obtained by a condensation polymerization reaction between an aromatic amine such as m- xylenediamine, and a dicarboxylic acid such as adipic acid, and its derivative, can be used. Since this laminated material A is excellent in barrier property for oxygen, steam and flavor, etc., this paper container is suitable for a filling-packaging of various kinds of liquid beverages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid paper container having a barrier property, and more specifically, milk, lactic acid bacterium drink, liquid soup, fruit juice drink, barley tea, which has a good oxygen barrier property. The present invention relates to a liquid paper container suitable for filling and packaging various liquid beverages such as green tea, oolong tea, alcoholic beverages and the like.

[0002]

2. Description of the Related Art Conventionally, various types of liquid paper containers suitable for filling and packaging various liquid beverages have been developed and proposed. For example, there is known a liquid paper container formed by using a laminated material having the following layer structure. (1) polyethylene layer / paper layer / polyethylene layer / aluminum foil layer / biaxially stretched polyethylene terephthalate film layer / polyethylene layer (2) polyethylene layer / paper layer / polyethylene layer / resin having a vapor deposited film of inorganic oxide Film layer / polyethylene layer (3) Polyethylene layer / paper layer / polyethylene layer / saponified ethylene / vinyl acetate copolymer layer / polyethylene layer (4) Polyethylene layer / paper layer / polyethylene layer / biaxially stretched polyamide film layer / Polyethylene layer (5) Polyethylene layer / paper layer / polyethylene layer / polyvinylidene chloride film layer / polyethylene layer

[0003]

However, as a matter of fact, the liquid paper container proposed above is excellent in one point but not sufficiently satisfactory in the other. Therefore, further development of new new products and new technologies for liquid paper containers is desired in the future. For example, in the liquid paper container according to the above specification (1), it is used as a long-term storage container for filling and packaging of alcoholic drinks such as sake, fruit juice drinks, seasonings, liquid soup and the like. However, since aluminum foil is used as a barrier base material, it is considered to be a cause of environmental damage, and various problems remain in the recovery of aluminum foil and disposal after use. . Further, in the liquid paper container according to the above specification (2), in order to solve the above problems of the aluminum foil as the barrier substrate, an alternative barrier
The present invention uses a resin film layer having an inorganic oxide vapor-deposited film as a functional base material, and is currently put into practical use mainly for filling and packaging of alcoholic beverages and the like. Compared with aluminum foil as a barrier material, its cost is high, and it is hard to say that it is a completely environmentally friendly packaging material in consideration of economy. Next, in the liquid paper container according to the above specification (3), a saponified product layer of an ethylene-vinyl acetate copolymer is laminated as a barrier layer. The oxygen barrier property of the saponified layer of is dependent on humidity, and especially when the relative humidity is close to 90%,
Since the oxygen barrier property of the saponified product layer of the ethylene-vinyl acetate copolymer is remarkably lowered, in reality, even when various beverages are filled and packaged, there is a problem in its long-term storage stability. is there. Further, in the liquid paper container according to the above specification (4), a biaxially stretched polyamide film layer is laminated as a barrier layer, and the biaxially stretched polyamide film layer is made of the above-mentioned ethylene-acetic acid. Compared with the saponified layer of vinyl copolymer, it has an advantage that the humidity dependency is low and the production cost of the obtained paper container is low, but there is a fatal problem that it is inferior in oxygen barrier property. However, at present, it is not so adopted.
Furthermore, in the liquid paper container according to the above specification (5), a polyvinylidene chloride film layer is laminated as a barrier layer with a polyethylene layer via an adhesive resin layer, but it has an oxygen barrier property. Gas barrier properties such as and water vapor barrier properties are sufficient, but the polyvinylidene chloride film layer, when burned, generates chlorine gas, hydrogen chloride gas, etc., and has the problem of significantly shortening the life of the incinerator. There is something. As described above, the conventional liquid paper container has many advantages and is currently in use, but it is still unsatisfactory, and a proposal for a new container is desired. It is rare. Therefore, the present invention provides a liquid paper container having excellent barrier properties against oxygen, water vapor, etc., and also having excellent heat resistance, suitability for filling and packaging the contents, excellent storage stability, and suitable for the environment. It is intended to be provided.

[0004]

As a result of various studies to solve the above problems, the present inventor has found that a crystalline aromatic polyamide resin has high strength, high elastic modulus, high heat resistance and high resistance. Focusing on having excellent chemical properties, low water absorption, low moisture permeability, gas barrier property, etc., in order to utilize the characteristics that it has, it contains a heat-adhesive resin layer as the innermost layer, and further paper In a liquid paper container made of a laminated material including a main support, a laminated material including a resin layer made of a crystalline aromatic polyamide resin is produced between the innermost layer and the support, and the laminated material is further laminated. Using the material, according to the standard method,
A blank plate capable of producing a paper container was produced, and then a box was made using this to produce a liquid paper container, which was excellent in barrier properties against oxygen, water vapor, etc., and was also excellent in heat resistance. The present invention has been completed by finding that it is possible to produce an extremely good packaged product which has suitability for filling and packaging contents, has excellent storability, and is environmentally friendly.

That is, the present invention provides a liquid paper container comprising a heat-adhesive resin layer as an innermost layer, and further comprising a laminated body containing a support mainly composed of paper, wherein the space between the innermost layer and the support is the same. In addition, the liquid paper container is characterized by comprising a laminated material including a resin layer made of a crystalline aromatic polyamide resin.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. First, in the present invention, an example of the liquid paper container according to the present invention will be exemplified and described with reference to the drawings. FIG. 1 is a schematic view showing an example of the layer structure of a laminated material constituting the liquid paper container according to the present invention. 2 is a schematic cross-sectional view, and FIG. 2 is a schematic perspective view showing an example of the configuration of a liquid paper container according to the present invention manufactured using the laminated material shown in FIG. 1. The laminated material A constituting the liquid paper container according to the present invention, as shown in FIG.
Thermal adhesive resin layer 1, adhesive resin layer 2 provided if necessary,
The resin layer 3 is made of a crystalline aromatic polyamide resin, the adhesive layer 4, the support 5 mainly made of paper, and the heat-adhesive resin layer 1'are laminated in this order.

As an example of a liquid paper container according to the present invention using the above-mentioned laminated material A, as shown in FIG. A blank plate for a paper container having a ruled line for punching a shaped paper container is punched out, and then the edges of the blank plates are overlapped with each other.
Produce the bubu 7. Next, in the present invention, the sleeve 7 manufactured as described above is mounted on a filling machine, and the bottom portion is folded along a predetermined ruled line and heat-bonded by hot air treatment to form the bottom portion 8. Then, the contents 9 are filled from the opening of the top, and then the top is folded along a predetermined ruled line and heat-bonded by hot air treatment, for example, a top having a bell-belt shape. 10 can be formed to manufacture the liquid paper container packaging product B having a predetermined shape according to the present invention. The examples given above are merely examples of the liquid paper container according to the present invention, and the present invention is not limited thereby.

By the way, in the present invention, in the laminated material A as described above, the resin layer 3 made of the crystalline aromatic polyamide-based resin is as shown in the sectional views showing the layer structure of FIGS. 3 and 4. , A polyamide-based resin layer 3a (FIG. 3) having a two-layer structure in which a resin layer 31 made of an aliphatic polyamide resin is laminated on one surface of the resin layer 3 made of a crystalline aromatic polyamide resin, or a crystalline aromatic It may be composed of a polyamide resin layer 3b (FIG. 4) having a three-layer structure in which resin layers 31, 31 made of an aliphatic polyamide resin are laminated on both surfaces of the resin layer 6 made of a polyamide resin.

Next, in the present invention, the materials constituting the above-described liquid paper container according to the present invention will be described. Various materials can be used as such materials. First, in the present invention, as the crystalline aromatic polyamide-based resin forming the resin layer of the crystalline aromatic polyamide-based resin, for example, metaxylene diamine,
Aromatic crystalline polyamide resin obtained by polycondensation reaction of an aromatic diamine such as paraxylenediamine and a dicarboxylic acid such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid or a derivative thereof Can be used. Specifically, for example, nylon MXD6 (trade name, manufactured by Mitsubishi Gas Chemical Co., Inc.) can be used. Thus, in the present invention, a molding method such as extrusion molding, injection molding, calendar processing, co-extrusion molding, co-injection molding or the like is used by using the aromatic crystalline polyamide resin as described above. Then, the resin layer can be formed into a film or a sheet to form a resin layer of the crystalline aromatic polyamide resin. Alternatively, according to the present invention, a resin composition containing an aromatic crystalline polyamide resin as a main component as described above is applied or printed to form a coated or printed film with the resin composition, and the crystalline aromatic A resin layer made of a group polyamide-based resin can be formed. In the present invention, the film or sheet made of the crystalline aromatic polyamide-based resin produced by the molding method as described above may be used in the production or production of the film or sheet by a usual method. Thereafter, the film is stretched in the biaxial directions in the vertical and horizontal directions to produce a film subjected to the biaxial stretching treatment. Thus, in the present invention, when the film or sheet biaxially stretched as described above is used as the resin layer made of the crystalline aromatic polyamide resin, it has a higher barrier property against oxygen, water vapor and the like. In addition to being able to exert the effect, it is possible to manufacture a laminated material having excellent heat resistance. In the above, the thickness of the resin layer made of the crystalline aromatic polyamide resin is, for example, about 5 to 100 μm, preferably 10 to 50 μm.
Position is desirable.

Next, in the above-mentioned present invention, as an aliphatic polyamide-based resin constituting a resin layer of an aliphatic polyamide-based resin laminated on one side or both sides of a resin layer of the above-mentioned crystalline aromatic polyamide-based resin Is, for example, hexamethylenediamine, decamethylenediamine,
Dodecamethylenediamine, 2,2,4- or 2,4,
Aliphatic and alicyclic diamines such as 4-trimethylhexamethylenediamine, 1,3- or 1,4-bis (aminomethyl) cyclohexane and bis (p-aminocyclohexylmethane), and adipic acid and suberic acid Polyamide resins obtained by condensation of aliphatic polyamides obtained by polycondensation reaction with dicarboxylic acids such as sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid and isophthalic acid or derivatives thereof, ε-aminocaproic acid, 11-aminoundecanoic acid, etc. And polyamide resins obtained from lactam compounds such as ε-caprolactam and ω-laurolactam, or mixtures thereof. Specifically, for example, nylon 6, nylon 66,
Nylon 9, Nylon 11, Nylon 12, Nylon 6
/ 66, nylon 66/610, and other aliphatic polyamide resins.

In the present invention, a method for laminating the resin layer made of the above aliphatic polyamide resin on one side or both sides of the resin layer made of the above crystalline aromatic polyamide resin is, for example, A film or sheet of the aliphatic polyamide resin is produced by extrusion molding, injection molding, calendering or the like using the aliphatic polyamide resin, and the film or sheet is made of a crystalline aromatic polyamide. A method for laminating a resin layer on one side or both sides of a resin layer, or using a crystalline aromatic polyamide resin and an aliphatic polyamide resin, using a molding method such as co-extrusion molding or co-injection molding. To form a co-extruded film or sheet, and to form an aliphatic polyamide resin on one or both sides of the resin layer made of the crystalline aromatic polyamide resin. It can be carried out by a method such as forming the fat layer. Alternatively, in the present invention, a resin composition containing an aliphatic polyamide resin as a main component as described above is applied or printed on one side or both sides of a resin layer made of a crystalline aromatic polyamide resin to obtain the resin composition. To form a resin layer of the crystalline aromatic polyamide resin. In addition,
In the present invention, a single film or sheet made of an aliphatic polyamide resin produced by the above-mentioned molding method, or a co-extruded film or sheet-like material is formed into a film or sheet by a conventional method. A film that has been subjected to the biaxial stretching treatment can be manufactured by stretching the product in the longitudinal and lateral biaxial directions during or after the production.
In the present invention, when a film or sheet that has been subjected to the biaxial stretching treatment as described above is used, a laminate having high barrier properties against oxygen, water vapor and the like and having high heat resistance is used. It can be manufactured. Further, in the present invention, the crystalline aromatic polyamide-based resin is inferior in film-forming property and stretchability to the aliphatic polyamide-based resin. Of the crystalline aromatic polyamide-based resin and the aliphatic polyamide-based resin because the film-forming property and the stretchability of the crystalline aromatic-polyamide-based resin are improved, and the cost of the crystalline aromatic polyamide-based resin is high. By using them together, it is possible to expect a reduction in the cost. That is, in the present invention, a crystalline aromatic polyamide-based resin and an aliphatic polyamide-based resin are used, both are coextruded and biaxially stretched, and a biaxially stretched co-extruded film composed of the both is obtained. It is desirable to manufacture sheets. In the above, the thickness of the resin layer made of the aliphatic polyamide resin is, for example, 5 to 100.
The μm position is preferably about 10 to 50 μm.

By the way, in the present invention, when a resin layer made of an aliphatic polyamide resin is laminated on one or both sides of a resin layer made of a crystalline aromatic polyamide resin, the total thickness is about 10 to 50 μm. It is more preferable that the thickness of the resin layer is 15 to 25 μm, and the thickness of the resin layer made of the crystalline aromatic polyamide resin is 1/10 to 1/3 of the total thickness of the aliphatic aromatic polyamide resin. The thickness of the resin layer made of polyamide resin is 9/10 to 2/3 of the total thickness.
Position is desirable.

Further, in the present invention, the material forming the heat-adhesive resin layer as the innermost layer may be any material that can be melted by heat and fused to each other, for example, low density polyethylene, medium density polyethylene. , High density polyethylene, linear low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-
Acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, polybutene polymer, acid-modified polyolefin resin, and other resin films Or a sheet can be used. The thickness of the film is 5 μm to 300 μm
And preferably about 10 μm to 100 μm.

Next, in the present invention, as the adhesive constituting the adhesive resin layer, for example, ethylene such as ethylene-methacrylic acid copolymer or ethylene-acrylic acid copolymer, and an unsaturated carboxylic acid are used. Copolymer, or acid-modified polyolefin resin obtained by modifying it with acid, ethylene-ethyl acrylate copolymer, ionomer resin,
Others can be used.

Further, in the present invention, the adhesive constituting the adhesive layer is, for example, a two-component curing type urethane adhesive, an acrylic adhesive, a polyester adhesive, or a polyamide which is used in dry laminating or the like. Adhesive,
A polyvinyl acetate adhesive, an epoxy adhesive, a rubber adhesive, etc. can be used. Alternatively, the adhesive or the like forming the adhesive resin layer can be used in the same manner.

Next, in the present invention, the support consisting mainly of paper is a basic material constituting a liquid paper container, and therefore is excellent in mechanical, physical, chemical, etc., and has rigidity and the like. It is possible to use various papers having the property of, for example, various paperboards, processed papers, coated papers, paper base materials such as acid resistant papers, thin papers, synthetic papers, and the like. . As the paper base material, for example, a basis weight of 7
It is possible to use one having a value of 0 to 300 g / cm ² .

Further, in the present invention, the same material as the above-mentioned material forming the heat-adhesive resin layer as the innermost layer can be used as the material forming the heat-adhesive resin layer as the outermost layer, Specifically, similar to the above, as long as they can be melted by heat and fused to each other, for example,
Low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer-resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene A film or sheet of a resin such as a methacrylic acid copolymer, an ethylene-propylene copolymer, a methylpentene polymer, a polybutene polymer, an acid-modified polyolefin resin, or the like can be used. The thickness of the film is 5 μm to 300
μm, preferably 10 μm to 100 μm. Thus, in the present invention, the heat-adhesive resin layer as the outermost layer as described above is obtained by punching out a blank plate for a paper container from a laminated material as described above, and then the ends of the upper and lower surfaces of the blank plate. Since the sleeve is manufactured by overlapping the edges and forming the welded portion by welding the polymerized end portions, the heat-adhesive resin layer forming the innermost layer and the material having the heat-adhesiveness are used. Therefore, the same material as the above-mentioned material constituting the heat-adhesive resin layer as the innermost layer is used, and a resin film or sheet that can be melted by heat and welded to each other is similarly used. It is preferable to use and laminate as the outermost layer.

Next, in the present invention, the packaging container is usually subjected to severe physical and chemical conditions, so that the packaging material constituting the liquid paper container is required to have strict packaging suitability. Therefore, various conditions such as deformation prevention strength, drop impact strength, pinhole resistance, heat resistance, sealing performance, quality maintenance, workability, hygiene, etc. are required. In addition to the above materials, other materials satisfying the above conditions can be optionally used. Specifically, for example, low density polyethylene, medium density polyethylene, high density polyethylene, Linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer
Resin, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid or methacrylic acid copolymer, methylpentene polymer, polybutene-based resin, polyvinyl chloride-based resin, polyvinyl acetate-based resin, polyvinylidene chloride-based resin, chloride Vinyl-vinylidene chloride copolymer, poly (meth) acrylic resin, polyacrylonitrile resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin) ), Polyester resin, polyamide resin, polycarbonate resin, polyvinyl alcohol, saponification product of ethylene-vinyl acetate copolymer, fluorine resin, diene resin, polyacetal resin, polyurethane resin Known resins such as resins, nitrocellulose, etc. Beam or sheet - Select from them on any can be used. In addition, for example, a film such as cellophane, synthetic paper, or the like can be used. In the present invention, the above-mentioned film or sheet can be used in any of unstretched and uniaxially or biaxially stretched. The thickness is arbitrary, but can be selected from a range of several μm to 300 μm. Further, in the present invention, the film or sheet may be any film such as an extruded film, an inflation film, or a coating film.

Next, in the present invention, if necessary, a barrier film layer may be laminated, and as a material for the barrier film layer, light such as sunlight can be used. The property of blocking light, or water vapor,
It is possible to use a material having a property of not permeating water, gas, etc., which may be a single base material or a composite base material in which two or more base materials are combined. Specifically, for example, a film of a resin having an aluminum foil having a light-shielding property and a barrier property or a vapor deposition film thereof, a film of a resin having a vapor deposition film of an inorganic oxide such as silicon oxide or aluminum oxide having a barrier property. ,
Film or sheet of resin such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, etc. having a barrier property against water vapor, water, etc., gas barrier property Polyvinylidene chloride having, polyvinyl alcohol, a film or sheet of a resin such as saponified ethylene-vinyl acetate copolymer, a colorant such as a pigment to the resin, and kneaded with other desired additives. It is possible to use films or sheets of various colored resins having a light-shielding property which are formed into a film by using the above. These materials are
One kind or a combination of two or more kinds can be used. The thickness of the above-mentioned film or sheet is arbitrary, but is usually about 5 μm to 300 μm, and further,
10 μm to 100 μm is desirable. Further, in the above, as the aluminum foil, 5 μm to 30
Thickness of about 100 μm or 2000 for vapor deposition film of aluminum or inorganic oxide.
Å can be used. Examples of the resin film supporting the above-mentioned vapor-deposited film include a polyester film, a polyamide film, a polyolefin film, a polyvinyl chloride film, a polycarbonate film, a polyvinylidene chloride film, a polyvinyl alcohol film, and an ethylene-acetic acid film. Saponified vinyl copolymer films and the like can be used.

Next, in the above-mentioned present invention, a method for producing a laminated material using the above-mentioned materials will be explained. As such a method, an ordinary packaging material is laminated.
Method such as wet lamination method, dry lamination method, solventless dry lamination method, extrusion lamination method, T-die coextrusion molding method, coextrusion lamination method, etc. You can Thus, in the present invention, when performing the above-mentioned lamination, the film can be subjected to a pretreatment such as a corona treatment and an ozone treatment, if necessary. Type), polyethyleneimine type, polybutadiene type, organic titanium type anchor, etc.
Coating agent, or known anchor coating agent such as polyurethane-based, polyacrylic-based, polyester-based, epoxy-based, polyvinyl acetate-based, cellulose-based, etc. laminate adhesive, and the like Agents and the like can be used.

The liquid paper container according to the present invention, which is manufactured by using the above materials, has the oxygen barrier property, the water vapor barrier property, the flavor barrier property, etc. as the material constituting the laminated material. Since it contains a resin layer made of an excellent crystalline aromatic polyamide-based resin, for example, milk, lactic acid bacteria drink, liquid soup, fruit juice drink, barley tea, green tea, oolong tea,
It is suitable for filling and packaging various liquid beverages such as alcoholic beverages and the like.

[0022]

EXAMPLES The present invention will be described more specifically with reference to examples. Example 1 A low density polyethylene was extruded on both sides of an acid resistant paper having a basis weight of 310 g / m ² by an extrusion lamination method to obtain a thickness of 2
A 0 μm resin layer was formed to prepare a support for the paper container laminated base material. Next, a low-density polyethylene film having a thickness of 50 μm, an intermediate layer made of nylon MXD6 (trade name, manufactured by Mitsubishi Gas Chemical Co., Inc.), and both outer layers made of 6 nylon 6
A biaxially stretched co-extruded polyamide film (thickness: 15 μm, manufactured by Mitsubishi Kagaku Co., Ltd., trade name Super Neil) having a three-layer structure of nylon / nylon MXD6 / 6 nylon.
And were laminated by the dry lamination method. In the above dry lamination method, a two-component curing type urethane adhesive was used, and the coating amount was 5 g (dry) / m ² . Thereafter, the support and the laminated film were melt-extruded through an anchor coating agent with the polyethylene resin layer surface and the biaxially stretched co-pressed polyamide film surface facing each other, and the thickness was 20 μm. Was extruded from the low density polyethylene to produce a laminated material for a liquid paper container having the following layer structure from the outer surface to the inner surface. 20 μm / low density polyethylene resin layer / 310 g / m ²
・ Acid-resistant paper / 20 μm ・ Low-density polyethylene resin layer / 20
μm / low density polyethylene resin layer / 15 μm / biaxially stretched co-extruded polyamide film / adhesive layer / 50 μm / low density polyethylene film

Example 2 Low-density polyethylene was extruded on both sides of acid-resistant paper having a basis weight of 280 g / m ² and extruded by the lamination method to obtain a thickness of 2
A 0 μm resin layer was formed to prepare a support for the paper container laminated base material. Next, a low-density polyethylene film having a thickness of 50 μm, an intermediate layer made of nylon MXD6 (trade name, manufactured by Mitsubishi Gas Chemical Co., Inc.), and both outer layers made of 6 nylon 6
A biaxially stretched co-extruded polyamide film (thickness: 15 μm, manufactured by Mitsubishi Kagaku Co., Ltd., trade name Super Neil) having a three-layer structure of nylon / nylon MXD6 / 6 nylon.
And were laminated by extrusion lamination using low-density polyethylene having a thickness of 20 μm melt-extruded through an anchor coating agent. Thereafter, the support and the laminated film were melt-extruded through an anchor coating agent with the polyethylene resin layer surface and the biaxially stretched co-pressed polyamide film surface facing each other, and the thickness was 20 μm.
Was extruded from the low density polyethylene to produce a laminated material for a liquid paper container having the following layer structure from the outer surface to the inner surface. 20 μm / low density polyethylene resin layer / 280 g / m ²
・ Acid-resistant paper / 20 μm ・ Low-density polyethylene resin layer / 20
μm / low density polyethylene resin layer / 15 μm / biaxially stretched co-extruded polyamide film / 20 μm / low density polyethylene layer / 50 μm / low density polyethylene film

Comparative Example 1 In Example 1 above, 6 nylon / nylon MXD was used.
Instead of the biaxially stretched co-extruded polyamide film having a thickness of 15 μm, which has a three-layer structure of 6/6 nylon, a thickness of 15 μm is used.
A liquid paper container having the following layer structure from the outer surface to the inner surface was performed in the same manner as in Example 1 except that a silicide film of a biaxially stretched ethylene-vinyl acetate copolymer having a thickness of μm was used. Laminated material was manufactured. 20 μm / low density polyethylene resin layer / 310 g / m ²
・ Acid-resistant paper / 20 μm ・ Low-density polyethylene resin layer / 20
μm low density polyethylene resin layer / 15 μm biaxially oriented ethylene-vinyl acetate copolymer silicide film / adhesive layer / 50 μm low density polyethylene film

Comparative Example 2 In the above Example 1, 6 nylon / nylon MXD
Instead of the biaxially stretched co-extruded polyamide film having a thickness of 15 μm, which has a three-layer structure of 6/6 nylon, a thickness of 15 μm is used.
A biaxially stretched 6-nylon film of μm was used, and otherwise the same as in Example 1 above, to produce a laminated material for a liquid paper container having the following layer structure from the outer surface to the inner surface. 20 μm / low density polyethylene resin layer / 310 g / m ²
・ Acid-resistant paper / 20 μm ・ Low-density polyethylene resin layer / 20
μm / low density polyethylene resin layer / 15 μm / biaxially stretched 6 nylon film / adhesive layer / 50 μm / low density polyethylene film

Experimental Example 1 The oxygen permeability of the laminated materials for liquid paper containers produced in the above Examples 1 and 2 and Comparative Examples 1 and 2 was measured. The oxygen permeability is 23 ° C., relative humidity 0%: 40 ° C., relative humidity 90 using an oxygen permeability measuring instrument [Oxtran, model name] manufactured by Modern Control Co., Ltd.
% Was measured under two conditions. The results are shown in Table 1 below.

[0027]

[Table 1] In the above, the room temperature / low humidity condition was 23 ° C./relative humidity 0%, and the high temperature / high humidity condition was 40 ° C./90% relative humidity.

As shown in Table 1 above, regarding the oxygen permeability, the laminated materials for liquid paper containers according to Examples 1 and 2 were first tested under any conditions of room temperature / low humidity and high temperature / high humidity. Even below, it is superior to the laminated material for liquid paper containers according to Comparative Example 2, and is the same as the laminated material for liquid paper containers according to Comparative Example 1 under normal temperature / low humidity conditions. It was excellent under high temperature / high humidity conditions.

Experimental Example 2 Next, the laminated materials for liquid paper containers prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were used. First, these laminated materials for liquid paper containers were punched out. Was used to prepare a ruled blank sheet, and then side-sealed using a frame processing machine to prepare a sleeve. Next, each of the sleeves manufactured above was mounted in a filling machine, the bottom was heat-sealed by hot air treatment, and then 900 m of distilled water was supplied from the mouth of the top.
1 was filled, and the top was then heat-sealed by hot air treatment to prepare each 1000 ml volume gel-bel top type liquid container package. Next, each of the container containers for liquids produced above was dropped vertically from the height of 90 cm to the container floor on the concrete floor surface, and the strength of the paper container was measured according to the liquid leakage state to determine the container strength. Tested. The results are shown in Table 2 below.

[0030]

[Table 2] In the above, the container strength was defined as the number of leaked containers / the number of tested containers.

As shown in Table 2, the liquid container package manufactured by using the laminated material for liquid paper containers according to Examples 1 and 2 showed almost no liquid leakage in the drop test.
The liquid container packages manufactured by using the laminated material for liquid paper containers according to Comparative Examples 1 and 2 were confirmed to have liquid leakage in a drop test. This is because the liquid container packages manufactured by using the laminated material for liquid paper containers according to Comparative Examples 1 and 2 have poor heat resistance as compared with those of Examples 1 and 2, and therefore, thermal pinhos are used during container molding. -It is considered that this is due to the occurrence of

[0032]

As is apparent from the above description, the present invention provides a crystalline aromatic polyamide resin having high strength and elastic modulus, excellent heat resistance, chemical resistance, etc., and low water absorption,
Focusing on having low moisture permeability, gas barrier property, etc., in order to utilize the characteristics possessed by it, it is composed of a laminated material containing a heat-adhesive resin layer as the innermost layer and further including a paper-based support. In the liquid paper container, between the innermost layer and the support, a laminated material containing a resin layer of a crystalline aromatic polyamide resin is manufactured, and further, by using the laminated material,
According to the standard method, a blank plate capable of manufacturing a paper container was manufactured, and then a liquid paper container was manufactured by box-making using this, which was excellent in barrier properties against oxygen, water vapor, etc., and also excellent in heat resistance. Has the suitability for filling and packaging the contents,
It is possible to produce an extremely good packaged product which is excellent in its storability and suitable for the environment.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of a laminated material that constitutes a liquid paper container according to the present invention.

FIG. 2 is a schematic perspective view showing an example of the configuration of a liquid paper container according to the present invention manufactured using the laminated material shown in FIG.

FIG. 3 is a schematic cross-sectional view showing a layer structure of a polyamide resin layer having a two-layer structure in which a resin layer made of an aliphatic polyamide resin is laminated on one surface of a resin layer made of a crystalline aromatic polyamide resin. is there.

FIG. 4 is a schematic cross-sectional view showing a layer structure of a polyamide resin layer having a three-layer structure in which a resin layer made of an aliphatic polyamide resin is laminated on both sides of a resin layer made of a crystalline aromatic polyamide resin. is there.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat-adhesive resin layer 1'Heat-adhesive resin layer 2 Adhesive resin layer 3 Resin layer made of crystalline aromatic polyamide-based resin 31 Resin layer made of aliphatic polyamide-based resin 3a Polyamide-based resin layer composed of 2 layers 3b Polyamide resin layer consisting of 3 layers 4 Adhesive layer 5 Support consisting mainly of paper 6 Welding part 7 Sleeve 8 Bottom part 9 Contents 10 Top part

Claims (5)

[Claims] 1. A liquid paper container comprising a heat-adhesive resin layer as an innermost layer and further comprising a support mainly composed of paper, wherein a crystalline material is provided between the innermost layer and the support. A liquid paper container comprising a laminated material including a resin layer made of an aromatic polyamide resin. 2. The liquid paper container according to claim 1, wherein the resin layer made of a crystalline aromatic polyamide resin is biaxially stretched. 3. A resin layer made of a crystalline aromatic polyamide resin comprises a polyamide resin layer composed of two or three layers in which a resin layer made of an aliphatic polyamide resin is laminated on one side or both sides thereof. The liquid paper container according to claim 1 or 2, characterized in that. 4. The liquid paper container according to claim 3, wherein the polyamide resin layer having a two-layer or three-layer structure is a laminate of coextrusion films. 5. The liquid paper container according to claim 4, wherein the laminate of the co-extrusion film is biaxially stretched.