JP2016078907A - Cup-state container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cup-state container formed by closing one end opening of a cylindrical trunk 2 with a bottom material 1, excellent in gas barrier property.SOLUTION: A bottom material is formed of a substrate 11 and a gas barrier layer 12, in which the gas barrier layer is a layer including a gas barrier composite structure formed by reaction of a polyvalent metal compound and a phosphorus compound. The composite structure is a composite structure in which metal atoms M and phosphorus atoms are bound by covalent bond expressed by M-O-P-O-M or M-O-(P-O-P)-O-M, when the polyvalent metal atom is expressed by M, in which plural phosphorus atoms P coordinate with the metal atom M as a center, and plural metal atoms M coordinate with the phosphorus atom P as a center. Therefore, the composite structure has a fine structure in which atoms are bound by covalent bond in a mesh-state, as the result, high gas barrier property is exhibited. In addition, the composite structure is excellent in resistance to bending or heat.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a cup-shaped container, and particularly to a cup-shaped container having gas barrier properties.

  As shown in FIGS. 1 and 2, the cup-shaped container rolls up the body sheet and joins both end portions thereof to produce the tubular body portion 2, and one end (lower end) of the tubular body portion. ) 2a is closed and covered with the bottom material 1. The bottom material 1 is bent at the lower edge and inserted into the lower end 2a of the cylindrical body, and the lower end 2a of the cylindrical body 2 is bent inward so as to wind up the bent portion 1a, and both are crimped. And fix. In FIG. 1, 2 c indicates a joint portion where both ends of the body portion sheet are joined, and x indicates a fixed portion where the bent portion 1 a and the tubular body lower end 2 a are fixed.

  Further, as shown in FIG. 1, after the upper end 2b of the cylindrical body portion is curled outward, the curled portion may be crushed to form a flange 2d. The flange 2d is used as a sealing portion when heat-sealing the lid material on the container opening (see Patent Document 1).

  By the way, gas barrier property may be calculated | required by a cup-shaped container according to the content to accommodate. In this case, both the bottom material 1 and the cylindrical body 2 need to have gas barrier properties. And in order to satisfy | fill this request | requirement of gas barrier property, the sheet | seat which has a metal vapor deposition layer and an inorganic vapor deposition layer has been utilized as the trunk | sheet part sheet | seat and the bottom material 1. FIG.

  However, as described above, when the lower end 2 a of the cylindrical body 2 is closed with the bottom material 1, it is necessary to bend the peripheral edge of the bottom material 1 downward. It is necessary to crimp together with the lower end 2a. At this time, due to damage applied to the periphery of the bottom material 1, there was a problem that a crack occurred in the vapor deposition layer and gas barrier properties were lowered.

  As the body sheet and bottom material 1 having gas barrier properties, a coating layer in which an inorganic layered substance (for example, montmorillonite, mica, layered talc, etc.) is dispersed in a resin (for example, polyvinyl alcohol resin, acrylic resin, etc.) Although what has is also known, gas barrier property may fall in the periphery of the bottom material 1 also in this case.

JP 2003-31636 A

  Then, this invention is a cup-shaped container comprised by closing the one end open part of a cylindrical trunk | drum with a bottom material, Comprising: It aims at providing the cup-shaped container excellent in gas barrier property.

That is, the invention according to claim 1 is a cup-shaped container configured by closing one end open part of the cylindrical body part with a bottom material,
The bottom material is configured to include a base material and a gas barrier layer, and the gas barrier layer is a layer including a gas barrier composite structure formed by a reaction between a polyvalent metal compound and a phosphorus compound. It is the cup-shaped container characterized.

  Next, the invention according to claim 2 is constructed by bending the bottom edge of the bottom material in the downward direction and crimping the lower end of the body portion to the bent portion, thereby closing the one end open portion of the body portion with the bottom material. It is a cup-shaped container of Claim 1 characterized by the above-mentioned.

  The invention according to claim 3 is the cup-shaped container according to claim 1 or 2, wherein the base material has a paper layer.

  The invention according to claim 4 is the cup-shaped container according to any one of claims 1 to 3, wherein the base material has a plastic layer.

  The invention according to claim 5 is the cup-shaped container according to any one of claims 1 to 4, wherein the cylindrical body portion has a gas barrier layer.

  The invention according to claim 6 is characterized in that the gas barrier layer of the cylindrical body is a layer including a gas barrier composite structure formed by a reaction between a polyvalent metal compound and a phosphorus compound. A cup-shaped container according to claim 5.

In the present invention, the bottom material includes a base material and a gas barrier layer, and the gas barrier layer is a gas barrier composite structure formed by a reaction between a polyvalent metal compound and a phosphorus compound. It is a layer that contains. In such a composite structure, when the polyvalent metal atom is represented by M, the metal atom M and the phosphorus atom are M—O—P—O—M or M—O— (P—O—P) _n —O. A composite structure bonded by a covalent bond represented by -M. Moreover, since the metal atom M is a polyvalent metal atom, a large number of phosphorus atoms P are coordinated around the metal atom M. On the other hand, since the phosphorus atom P is also a polyvalent atom, the phosphorus atom P is centered. A number of metal atoms M coordinate. For this reason, the composite structure becomes a dense structure covalently bonded in a network shape, and as a result, exhibits a high gas barrier property. In addition, since this composite structure is excellent in resistance to bending and heat, the periphery of the bottom material provided with the gas barrier layer containing the composite structure is bent, and the bent portion is crimped together with the body portion. High gas barrier properties can be maintained. For this reason, it can be set as a cup-shaped container excellent in gas barrier property.

FIG. 1A is a perspective view showing an example of a cup-shaped container, and FIG. 1B is a sectional view thereof. FIG. 2 is a cross-sectional view showing the cup-shaped container assembly process. FIGS. 3A and 3B are cross-sectional views showing examples of the bottom material of the present invention. FIG. 4 is a cross-sectional view showing an example of a bottom material according to a comparative example.

  Next, the present invention will be described based on specific examples. As shown in FIG.1 and FIG.2, the cup-shaped container of this invention uses the bottom material 1 and the cylindrical trunk | drum 2 as an essential component. The cylindrical trunk | drum 2 can be produced by rolling up the trunk | drum sheet | seat and joining the both ends. And the cup-shaped container of this invention can be manufactured by closing the one end open part of this cylindrical trunk | drum 2 with the bottom material 1. FIG. As can be seen from FIG. 1 and FIG. 2, the peripheral edge of the bottom member 1 is bent downward and inserted into the lower end 2 a of the cylindrical body 2, and the lower end 2 a of the cylindrical body 2 is moved so that the bent portion 1 a is wound. The bottom end material 1 can be closed with the one end open portion of the body portion 2 by bending the inside and pressing and fixing both. And if necessary, after curling the upper end of the cylindrical trunk | drum 2 outside, this curled part can also be crushed and it can also be set as the flange 2d. The flange 2d can be used when a lid (not shown) is heat sealed to seal the cup-shaped container.

  The cup-shaped container of the present invention is characterized by the layer structure of the bottom material 1. That is, the bottom material 1 includes a base material 11 and a gas barrier layer 12, and the gas barrier layer 12 includes a specific composite structure. The substrate 11 preferably has a paper layer 111. As shown in FIGS. 3A and 3B, the substrate 11 may have a plastic layer 112 in addition to the paper layer 111. Further, the bottom material 1 may have other layers in addition to the base material 11 and the gas barrier layer 12. In any case, the gas barrier layer 12 is used by being arranged on the inner surface side of the cup-shaped container with respect to the base material 11. The bottom material 1 of FIG. 3A uses a sheet in which a plastic layer 112 is laminated on the outer surface side of a paper layer 111 as a base material 11, and a gas barrier layer 12 and a resin layer 13 are arranged in this order on the inner surface side. Laminated. 3B uses a sheet in which a plastic layer 112 is laminated on the outer surface side of the paper layer 11 as the base material 11, and the resin layer 14, the gas barrier layer 12, The resin layer 13 is laminated in this order. The resin layer 13 exposed on the inner surface of the cup-shaped container is preferably composed of a material that can be heat-sealed with the cylindrical body 2. For example, low density polyethylene, medium density polyethylene, and linear low density polyethylene.

By the way, the composite structure needs to be a gas barrier composite structure formed by a reaction between a polyvalent metal compound and a phosphorus compound. A gas barrier layer containing such a gas barrier composite structure is prepared by mixing a solution or dispersion containing a polyvalent metal compound with a solution containing a phosphorus compound to form a coating solution, and applying the coating solution to a substrate. After drying and removing the solvent, these polyvalent metal compounds and phosphorus compounds can be reacted to form. When a polyvalent metal atom is represented by M, this reaction causes a bond represented by M—O—P—O—M or M—O— (P—O—P) between the metal atom M and the phosphorus atom. A bond represented by _n- OM is generated. In the formula, n arbitrarily represents an integer. As described above, this composite structure has a high gas barrier property and is excellent in bending resistance and heat resistance. Therefore, even if the periphery of the bottom material 1 including the gas barrier layer including the composite structure is bent, Even if the bent portion 1a is pressure-bonded together with the lower end 2a of the body portion 2, high gas barrier properties can be maintained.

  Any element can be used as the polyvalent metal element as long as it can react with two or more molecules of the phosphorus compound. It may be a metalloid element. For example, elements such as magnesium, calcium, zinc, aluminum, silicon, titanium, and zirconium. Among these, aluminum is desirable.

  As the compound of these metal elements, any compound can be used as long as it can form a composite structure by reacting with a phosphorus compound. Generally, it is a compound having a hydroxyl group. The metal compound may be supplied in the form of a solution dissolved in a solvent, or may be supplied in the form of a dispersion in which fine particles of the metal compound are dispersed in a solvent.

  For example, aluminum nitrate can be supplied as a metal compound in the form of an aqueous solution thereof.

Alternatively, the metal oxide fine particles may be dispersed in water or an aqueous solvent and supplied in the form of a dispersion. Desirably, it is a dispersion of aluminum oxide fine particles. In general, metal oxide fine particles have a hydroxyl group on the surface, and the presence of this hydroxyl group reacts with the phosphorus compound to form the bond. The metal oxide fine particles can be synthesized, for example, by hydrolyzing a compound in which a hydrolyzable characteristic group is bonded to a metal atom, and condensing the hydrolyzable organism. Examples of the compound that can be used as the raw material include aluminum chloride, aluminum triethoxide, and aluminum isopropoxide. In order to improve the gas barrier properties, it is desirable that the metal oxide fine particles have an average particle size in the range of 1 to 100 nm.

  Next, as the phosphorus compound, any phosphorus compound can be used as long as it can react with a polyvalent metal compound to form the bond. Typical examples are phosphoric acid compounds and derivatives thereof. For example, phosphoric acid, polyphosphoric acid, phosphorous acid, phosphonic acid and the like. As polyphosphoric acid, pyrophosphoric acid, triphosphoric acid, or polyphosphoric acid condensed with 4 or more phosphoric acids can be used. Moreover, as a derivative | guide_body of a phosphoric acid type compound, the salt, ester (for example, trimethyl phosphate), or a halide may be sufficient, and a dehydration thing (for example, phosphorus pentoxide) and a halide can be illustrated.

  The phosphorus compound can be supplied in the form of a solution. For example, an aqueous solution using water as a solvent. It can also be supplied in the form of a solution of a hydrophilic organic solvent. For example, a lower alcohol solution.

  As described above, the solution or dispersion of the polyvalent metal compound and the solution of the phosphorus compound can be mixed to form a coating solution. Other components can also be added to this coating solution. For example, polymer compounds, metal complexes, clay compounds, crosslinking agents, plasticizers, antioxidants, ultraviolet absorbers, flame retardants, and the like. Examples of the polymer compound include polyvinyl alcohol, partially saponified polyvinyl acetate, polyhydroxyethyl (meth) acrylate, polysaccharides (eg, starch), acrylic polymers (eg, polyacrylic acid, polymethacrylic acid, Acrylic acid-methacrylic acid copolymer) and salts thereof, ethylene-vinyl alcohol copolymer, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride alternating copolymer Saponified ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, and the like.

  The coating film obtained by applying this coating solution, removing the solvent and drying is subjected to, for example, heat treatment to react the polyvalent metal compound with the phosphorus compound to form the bond, and according to the present invention. A gas barrier layer 12 including a gas barrier composite structure can be formed. The thickness of the coating film may be 0.1 μm or more. For example, it is 0.2 μm or more. Further, it may be 4.0 μm or less. Preferably it is 2.0 micrometers or less.

  Next, the heat treatment temperature is desirably 110 ° C. or higher, and more desirably 140 ° C. or higher. If the heat treatment temperature is low, the time required to produce sufficient bonds is lengthened and productivity is lowered. The heat treatment time may be 5 to 300 seconds. This heat treatment can be performed by, for example, an oven.

  In addition, even if reaction of a polyvalent metal compound and a phosphorus compound is inadequate by this heat processing, both can fully react by heating the bottom material 1 at the time of cup molding. For example, when crimping the bent portion 1a at the periphery of the bottom material to the lower end 2a of the body, by applying hot air of 200 to 300 ° C. to the bottom material 1 prior to the crimping, the resin layer on the surface is melted simultaneously, The reaction can be promoted. In this case, the bent portion 1a and the lower end 2a of the bottom material periphery can be heat-sealed to each other.

Next, as the body portion sheet constituting the cylindrical body portion 2, it is desirable to use a sheet in which paper is used as a base material and a gas barrier layer is laminated on the base material. As the gas barrier layer, a layer containing a gas barrier composite structure formed by a reaction between a valent metal compound and a phosphorus compound can be used as in the case of the gas barrier layer of the bottom material. In addition, a metal foil or a metal vapor deposition layer or an inorganic vapor deposition layer can also be used as a gas barrier layer. Moreover, you may have another layer. Desirably, it is a trunk | sheet part sheet | seat which has a heat-sealable resin layer on both front and back.

  In addition, the cup-shaped container of this invention can heat-seal and seal a lid | cover material by forming the flange part 2d around an upper surface opening part. Of course, it is desirable to use a lid having a gas barrier property.

Example 1
In this example, a laminated sheet having the layer configuration of FIG. 3A is used for both the bottom material and the body portion. Therefore, the manufacturing process will be described later.

First, MC cup base paper (single-side coated paper, basis weight 260 g / m ² ) manufactured by Oji F-Tech Co., Ltd. was used as the paper 111. After the coated surface was subjected to corona discharge treatment, a coating solution containing aluminum oxide fine particles and a phosphorus compound was applied and dried. The application amount is 0.4 g / m ² . Further, the coating method is gravure coating, and the coating plate is a diagonal plate with 150 lines / inch and a depth of 55 μm. Next, heating was performed in an oven at 140 ° C. for about 30 seconds to cause the aluminum oxide fine particles contained in the coating film to react with the phosphorus compound, thereby forming the gas barrier layer 12 including the gas barrier composite structure.

  Next, a low-density polyethylene resin was melt-extruded and coated to a thickness of 30 μm on the gas barrier layer 12 to form an inner surface side resin layer 13. Moreover, after printing on the paper 111, this ink film was covered, the low density polyethylene resin was melt-extruded and coated to a thickness of 20 μm, and the outer surface side resin layer 112 was obtained.

  Next, the laminated body obtained in this way was used as a body portion sheet, and this was rolled up and joined at both end portions thereof to produce a tubular body portion 2. The joint 2c was subjected to a known sky hemming process so that the end face of the paper was not exposed on the inner surface of the cup-shaped container.

  The same laminated sheet was used as the bottom material 1. And after bending a periphery downward, it inserts in the lower end 2a of the cylindrical trunk | drum 2, hot air is applied to both the bottom material 1 and the cylindrical trunk | drum lower end 2a, the surface polyethylene resin 13 is fuse | melted, and it bends. The lower end 2a of the cylindrical body part 2 was bent inward so as to involve the part 1a, and both were heat-sealed and fixed.

  And after curling the upper end of the cylindrical trunk | drum 2 outside, this curled part was crushed and the flange 2d was formed.

  The oxygen permeability of the cup-shaped container thus obtained was measured by the Mocon method and found to be 0.004 cc / pg / day.

  In addition, this cup-shaped container is filled with a gel that turns blue when exposed to oxygen, and a gas barrier lid is heat-sealed and sealed in the opening, and then left for one week to check for the presence or absence of a portion that changes color. Examined. The gel is a mixture of agar powder with sucrose fatty acid ester, caustic soda, methylene blue, and D-glucose. As a result, it was not possible to observe the portion that turned blue, including the fixed portion x between the body portion 2 and the bottom material 1.

(Example 2)
In this example, a sheet having the layer configuration of FIG. 3B is used for both the bottom material 1 and the body 2. The manufacturing process will be described later.

First, a cup base paper (basis weight 250 g / m ² ) manufactured by Daishowa Paperboard Co., Ltd. was used as the paper 111. Then, using a twin extrusion laminator, low-density polyethylene was melt-extruded and coated on both sides. The polyethylene layer 112 located on the outer surface side of the cup-shaped container has a thickness of 20 μm, and the polyethylene layer 14 located on the opposite side thereof has a thickness of 17 μm.

Next, after the surface of the polyethylene layer 14 having a thickness of 17 μm was subjected to a corona discharge treatment, a coating solution containing aluminum oxide fine particles and a phosphorus compound was applied and dried. The coating amount is 0.3 g / m ² . Further, the coating method is gravure coating, and the coating plate is a hatched plate with 200 lines / inch and a depth of 30 μm. Next, it heated for about 30 seconds in 110 degreeC oven, the aluminum oxide microparticles and phosphorus compound which were contained in the coating film were made to react, and the gas barrier layer 12 containing a gas barrier composite structure was formed.

  Then, a low density polyethylene resin was melt-extruded and coated to a thickness of 30 μm on the gas barrier layer 12 to form an inner surface side resin layer 13.

  Next, a cup-shaped container was produced in the same manner as in Example 1 using the laminated sheet thus obtained as the body sheet and the bottom material 1. The oxygen transmission rate by the Mocon method was 0.004 cc / pg / day.

  Further, as in Example 1, after filling and sealing a gel that turns blue when exposed to oxygen, the gel was left for one week and examined for the presence or absence of the part that changed color. The portion that changed to blue, including x, could not be observed.

(Comparative example)
In this example, a laminated sheet having the layer configuration of FIG. 4 is used for both the bottom material and the body portion. That is, this laminated sheet uses a vapor-deposited laminated film 16 in which a vapor-deposited film 161 is first formed by forming a silicon oxide vapor-deposited film on a polyester film, and a low-density polyethylene layer is laminated on the front and back. Note that one of the front and back low-density polyethylene layers is the inner surface side resin layer 13 and the other is the intermediate layer 162. And this vapor deposition laminated film 16 and paper 111 are laminated | stacked through the polyethylene layer 15, and the outer surface side resin layer 14 is laminated | stacked on the opposite side (outer surface side) of the paper 111, and is comprised. The manufacturing process will be described below.

  That is, first, low-density polyethylene was melt-extruded and coated on both surfaces of the vapor deposition film 161 to form the inner surface side resin layer 13 and the intermediate layer 162. The inner surface side resin layer 13 has a thickness of 30 μm, and the intermediate layer 162 has a thickness of 15 μm.

Next, MC cup base paper (single-side coated paper, basis weight 260 g / m ² ) manufactured by Oji F-Tech Co., Ltd. was used as the paper 111. Then, low-density polyethylene was melt-extruded and coated between the paper 111 and the intermediate layer 172 of the vapor-deposited laminated film 16, and the paper 111 and the vapor-deposited laminated film 16 were adhered by the molten polyethylene 15. Then, a low density polyethylene resin was melt-extruded and coated to a thickness of 20 μm on the outer surface side of the paper 111 to form the outer surface side resin layer 112.

  Next, a cup-shaped container was produced in the same manner as in Example 1 using the laminated sheet thus obtained as the body sheet and the bottom material 1. The oxygen permeability by the Mocon method was 0.010 cc / pg / day, indicating oxygen permeability several times that of Examples 1 and 2.

Next, in order to search for the cause of the high oxygen permeability in this way, as in Example 1, the gel that turns blue when exposed to oxygen is filled, sealed, and left for one week, where the color change occurs. When the presence or absence was examined, the fixing portion x between the trunk portion and the bottom material locally turned blue. From this result, it can be inferred that the silicon oxide vapor-deposited film is cracked in the fixed portion x, and the oxygen barrier property is lowered due to the crack.

DESCRIPTION OF SYMBOLS 1: Bottom material 11: Base material 111: Paper 112: Resin layer 12 Gas barrier layer 13: Resin layer 14: Resin layer 1a: Bending part 2: Cylindrical trunk | drum 2a: trunk | drum lower end 2b: trunk | drum upper end 2c: Joining part 2d: Flange x: Fixing part of bottom material and cylindrical body part

Claims (6)

In a cup-shaped container configured by closing one end open part of the cylindrical body part with a bottom material,
The bottom material is configured to include a base material and a gas barrier layer, and the gas barrier layer is a layer including a gas barrier composite structure formed by a reaction between a polyvalent metal compound and a phosphorus compound. Characteristic cup-shaped container.   2. The structure according to claim 1, wherein a bottom end of the body portion is closed with a bottom material by bending the periphery of the bottom material downward and crimping the lower end of the body portion to the bent portion. Cup-shaped container.   The cup-shaped container according to claim 1 or 2, wherein the substrate has a paper layer.   The cup-shaped container according to any one of claims 1 to 3, wherein the substrate has a plastic layer.   The cup-shaped container according to claim 1, wherein the cylindrical body portion has a gas barrier layer.   6. The cup-shaped container according to claim 5, wherein the gas barrier layer of the cylindrical body is a layer containing a gas barrier composite structure formed by a reaction between a polyvalent metal compound and a phosphorus compound.