JP7524557B2 - Packaging material for tube containers and tube containers - Google Patents

Description

The present invention relates to packaging materials for tube containers and tube containers.

Conventionally, tube containers are known that include packaging materials for tube containers having an outer sealant layer, a base layer, and an inner sealant layer, which are layered in this order from the outer surface to the inner surface. In addition, a pattern or the like is printed in advance on the base layer by a printing method such as gravure printing (for example, Patent Document 1).

JP 2001-301071 A

However, when a tube filled with ice cream or the like is removed from the freezer, the surface temperature of the tube is below freezing. When the user presses the body of the tube with their fingers to consume the drink, the fingers in contact with the body become extremely cold, making it impossible to continue to press the tube, which can interfere with the drink's ability to be consumed.

In addition, when the tube container is filled with soup or the like, it is placed in a heating chamber of a heating device to maintain the soup at a specified heating temperature. Therefore, when the tube container filled with soup or the like is removed from the heating chamber of the heating device, the surface temperature of the tube container is considerably high, and when the body of the tube container is pressed with the fingers of the hand to drink it, the pressure with the fingers cannot be continued, which can cause problems in drinking.

The present invention was made in light of these circumstances, and its purpose is to provide a packaging material for tube containers and a tube container that has an insulating structure that insulates the temperature of the contents, making it easy to hold in the hand.

That is, the present invention relates to a packaging material for tube containers having a pair of bonded ends, which comprises at least an outer sealant layer, a base layer, a heat insulating layer, and an inner sealant layer arranged in this order from the outer surface to the inner surface, and the heat insulating layer includes a foam layer.

The present invention also provides a tube container comprising a cylindrical body portion in which opposing ends of a packaging material for a tube container are overlapped and joined together, and a head member joined to one end of the cylindrical body portion.

According to the present invention, the body member for the tube container has a heat insulating structure, so that a tube container can be provided that can be held in the hand without feeling too cold or hot even when ice cream, soup, or other contents are inside the container body.

FIG. 1 is a side cross-sectional view showing a laminate of packaging materials for tube containers. FIG. 2 is a side cross-sectional view showing the heat insulating layer. FIG. 3 is a diagram showing a method for manufacturing a tube container. FIG. 4 is a diagram showing a method for manufacturing a tube container. FIG. 5 is a side cross-sectional view showing a packaged product including a tube container. FIG. 6 is a diagram showing a method for manufacturing a tube container.

The packaging material for tube containers and the tube containers according to the embodiments of the present invention will be described in more detail below with reference to the drawings, etc.

First, referring to Figures 3 to 5, we will describe a tube container 20 made using the packaging material 10 for tube containers according to the present invention.

The tube container 20 has a cylindrical body 21 containing the tube container packaging material 10, and a shoulder 13 and a mouth 14 made by applying resin to the cylindrical body 21 by compression molding. A cap 16 is attached to the mouth 14 of the tube container 20.

The tube container 20 having such a configuration is obtained through the following manufacturing process.

First, as shown in FIG. 3, a pair of bonded ends (hereinafter also referred to as both ends) 11, 11' of the tube container packaging material 10 according to the present invention are overlapped, and the outer and inner surfaces of the overlapped parts are heat-sealed and bonded together to form a heat-sealed part 12, thereby manufacturing a cylindrical body 21. Next, as shown in FIG. 4, the cylindrical body 21 is placed in a mold (not shown), and a shoulder 13 and a mouth 14 are formed at one opening 21A of the cylindrical body 21 by a normal method such as compression molding. In this way, the shoulder 13 and the mouth 14 are integrally molded at one opening 21A of the cylindrical body 21, and a tube container 20 is produced. Then, a cap 16 is attached to the mouth 14 of the tube container 20.

Next, as shown in FIG. 5, an appropriate amount of, for example, frozen dessert or other contents 17 is filled into the other opening 21B of the cylindrical body 21 of the tube container 20. After that, the other opening 21B is welded to form a bottom seal 18, and a packaged product 20A including the tube container 20 filled and packaged with the contents 17 is obtained.

Next, referring to Figures 1 and 2, we will describe the packaging material 10 for tube containers, which is used to make tube containers 20.

The packaging material 10 for tube containers according to the first embodiment shown in FIG. 1 includes an outer sealant layer 1, a base layer 2 having a printed layer 2a, a heat insulating layer 3, a gas barrier layer 4, and an inner sealant layer 5, which are arranged in this order from the outer surface to the inner surface.

The outer sealant layer 1 and the base layer 2 are joined by dry lamination (DL), the base layer 2 and the heat insulating layer 3 are joined by dry lamination (DL), the heat insulating layer 3 and the gas barrier layer 4 are joined by dry lamination (DL), and the gas barrier layer 4 and the inner sealant layer 5 are also joined by dry lamination (DL). The foamed layer 3a and the non-foamed layer 3b are joined by inflation film molding.

The heat insulating layer 3 shown in FIG. 2(a) contains a foamed layer 3a and a non-foamed layer 3b. The foamed layer 3a and the non-foamed layer 3b are laminated by inflation film molding.

The heat insulating layer 3 shown in FIG. 2(b) has a foamed layer 3a disposed between a non-foamed layer 3b and a non-foamed layer 3c. The foamed layer 3a and the non-foamed layers 3b and 3c are laminated by inflation film molding.

In this specification, the terms "outer surface" and "inner surface" refer to the "outer surface" and "inner surface" when a tube container 20 is produced using the tube container packaging material 10. Note that the above-mentioned Figs. 1 and 2 show examples of the tube container packaging material according to the present invention, and the present invention is not limited thereto.

Next, we will describe the materials that make up each part of the tube container packaging material 10.

The insulating layer 3 may be any layer that insulates the temperature of the contents of the tube container. Specifically, the foam layer 3a functions as the insulating layer.

In this embodiment, the foam layer 3a can be made of, for example, a foamed polyolefin resin as the base polymer.

The polyolefin resin is, for example, a homopolymer or copolymer of an olefin such as ethylene or propylene. Examples of such polymers include polyethylenes such as high density polyethylene (HDPE), medium density polyethylene (MDPE), high pressure low density polyethylene (LDPE), linear low density polyethylene (LLDPE), copolymers mainly made of ethylene such as ethylene-vinyl acetate copolymer and ethylene-acrylic acid copolymer, polypropylenes such as propylene homopolymer (PP) and propylene-ethylene copolymer, and other resins. Polyethylene, polypropylene, and mixtures of polyethylene and polypropylene are preferred. This is because the use of such polyolefin resins makes it easier to form bubbles.

Examples of blowing agents that foam the base polymer include organic chemical blowing agents that generate nitrogen gas, such as azo compounds such as azodicarbonamide, barium azocarboxylate, and azobisisobutyronitrile, nitroso compounds such as N,N'-dinitrosopentamethylenetetramine, hydrazine compounds such as hydrazocarbonamide, and hydrazide compounds such as p-toluenesulfonylhydrazide, inorganic chemical blowing agents that generate carbon dioxide gas, such as sodium bicarbonate, ammonium carbonate, and ammonium bicarbonate, and propane, n-butane, i-butane, n-pentane, and the like. Examples of physical blowing agents include lower aliphatic hydrocarbon compounds such as ethane, i-pentane, and hexane, alicyclic hydrocarbon compounds such as cyclobutane and cyclopentane, aromatic hydrocarbon compounds such as benzene, toluene, and xylene, lower aliphatic monohydric alcohol compounds such as methanol and ethanol, lower aliphatic ketone compounds such as acetone and methyl ethyl ketone, and low-boiling halogenated hydrocarbon compounds such as chloromethyl, chloroethyl, and 1-chloro-1,1-difluoroethane; and physical blowing agents made of gases such as argon gas, helium gas, freon gas, carbon dioxide gas, and nitrogen gas.

Among these foaming agents, carbon dioxide gas and nitrogen gas are preferred because they are non-toxic and suitable for food applications.

Furthermore, the foam layer 3a can contain resins other than polyolefin-based resins, such as ethylene-propylene rubber, elastomer resins such as styrene-based thermoplastic elastomers, adhesive resins such as modified polyolefins, and polyester-based biodegradable resins such as polylactic acid.

In addition, optional ingredients such as starches, lubricants, pigments, antistatic agents, rust inhibitors, antibacterial agents, oxygen scavengers, and bulking agents can be blended into the foam layer 3a as needed, provided that the objective of the present invention is not impaired.

The amount of foaming agent in the foam layer 3a can be determined taking into consideration the type of polyolefin resin and the desired foaming rate, and is preferably 0.01 to 2.0% by mass, and more preferably 0.03 to 1.5% by mass.

The expansion ratio of the foam layer 3a is preferably 1.1 to 5 times, more preferably 2 to 4 times, and even more preferably 2.5 to 3.5 times. If the expansion ratio of the foam layer is less than 1.1 times, air bubbles are difficult to form, and if the expansion ratio exceeds 5 times, it is difficult to form uniform air bubbles. If the expansion ratio is 1.1 to 5 times, air bubbles are easily formed and the void ratio and bulk density of the foam layer are easily controlled. Here, the expansion ratio is a value calculated by the formula (resin density of the foam layer before expansion) / (film density of the foam layer after expansion).

The thickness of the foam layer 3a can be determined according to the application of the tube container, and is preferably 50 to 200 μm, more preferably 60 to 180 μm, for example. If the thickness of the foam layer 3a is 50 μm or more, sufficient heat insulating effect is ensured, and if it is 200 μm or less, flexibility of the tube container is ensured.

The porosity of the foamed layer 3a is preferably 30 to 70 volume %, more preferably 35 to 65 volume %, and further preferably 40 to 60 volume %. If the porosity is within the above range, the contents such as ice cream will not feel very cold even if they are placed in the container body.
Here, the void ratio is the proportion of air bubbles that are in communication with the outside of the foam layer, and can be calculated by the formula: void ratio (volume %) = (total volume of air bubbles in the foam layer) ÷ (apparent volume of the foam layer) × 100.

The bulk density of the foam layer 3a is preferably 0.20 to 0.60 g/cm ³ , more preferably 0.30 to 0.55 g/cm ³ , and further preferably 0.30 to 0.45 g/cm ^3. If the bulk density is within the above range, the heat insulating effect and the effect of suppressing the sensible temperature are improved.

The heat insulating layer 3 may further include non-foamed layers 3b and 3c.
The non-foamed layers 3b and 3c are non-foamed resin layers made of a resin containing a thermoplastic resin and cover the foamed layer 3a. The non-foamed layers 3b and 3c may be made of the same material or different materials as long as they are made of a resin containing a thermoplastic resin.

The thermoplastic resin is not particularly limited, and examples thereof include polyethylenes such as high density polyethylene (HDPE), medium density polyethylene (MDPE), high pressure low density polyethylene (LDPE), linear low density polyethylene (LLDPE), etc.; copolymers mainly composed of ethylene such as ethylene-vinyl acetate copolymer and ethylene-acrylic acid copolymer; polypropylenes such as propylene homopolymers and propylene-ethylene copolymers; polyesters such as polyethylene terephthalate; and polyamides. Among these, polyethylene is preferred, and linear low density polyethylene is more preferred, since low temperature heat sealability and heat seal strength are required when used as a tube container.

The thickness of the non-foamed layer 3b can be determined taking into consideration the use of the tube container and the thickness of the foamed layer 3a, and is preferably 15 to 60 μm, and more preferably 20 to 50 μm. If the thickness of the non-foamed layer 3b is 15 μm or more, the non-foamed layer can be prevented from opening following the formation of the openings in the foamed layer 3a, and if it is 60 μm or less, the flexibility of the tube container can be ensured.

The manufacturing method of the heat insulating layer 3 of this embodiment may, for example, be a method of co-extruding a foamable mixture and a non-foamable mixture, foaming the foamable mixture to form a foamed layer 3a, while forming non-foamed layers 3b, 3c made of the non-foamable mixture on one or both sides of the foamed layer. The foamable mixture is a resin mixture containing a polyolefin resin and a foaming agent, and the non-foamable mixture is a resin mixture containing a thermoplastic resin.

In addition, it is preferable to apply inflation film molding to form the foamed layer 3a and the non-foamed layers 3b and 3c. Examples of inflation film molding include multi-layer inflation film molding using a circular die.

The outer sealant layer 1 and the inner sealant layer 5 may contain, for example, polyethylene (PE). Specifically, the outer sealant layer 1 and the inner sealant layer 5 may be made of the following materials:

The outer sealant layer 1 and the inner sealant layer 5 may be any layer that can be melted and fused to each other by heat, and may be, for example, one or more of low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene (PP), ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, acid-modified polyolefin resins obtained by modifying polyolefin resins such as polyethylene or polypropylene with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, and others, polyvinyl acetate resins, polyester resins, polystyrene resins, and others.

In this embodiment, the outer sealant layer 1 and the inner sealant layer 5 are, for example, mainly composed of one or more of the above resins, to which desired additives are optionally added to prepare a resin composition, and then the resin composition prepared above can be used to mold a film or sheet, for example, using the T-die method, the inflation method, or other molding methods.

The materials for the outer sealant layer 1 and the inner sealant layer 5 may contain, for example, an antiblocking agent, a lubricant (such as a fatty acid amide), an antistatic agent, a flame retardant, an inorganic or organic filler, etc.

In this embodiment, the thickness of the outer sealant layer 1 and the inner sealant layer 5 is preferably 10 μm or more and 200 μm or less, and more preferably 30 μm or more and 180 μm or less.

The base layer 2 can be made of any material that has the strength, toughness, and heat resistance required to be the basic material that constitutes the tube container.

Materials that can be used to form the base layer 2 include, for example, polyester resins, polyamide resins, polyaramid resins, polyolefin resins, polycarbonate resins, polyacetal resins, fluorine resins, and other tough resin films or sheets, and the like.

Among the above, polyester resins, particularly polyethylene terephthalate (PET) resins, are preferred in terms of forming a printing layer. Here, polyethylene terephthalate resins refer to pure polyethylene terephthalate resins and various modified polyethylene terephthalate resins.

The substrate layer 2 may be an unstretched film or a uniaxially or biaxially stretched film. Among these, in this embodiment, a biaxially stretched polyester resin film is preferred because it is excellent for forming a printing layer.

In this embodiment, the thickness of the base layer 2 is preferably 10 μm or more and 25 μm or less.

The printing layer 2a is used to form a pattern or other design on the body of the tube container.

The printing layer 2a can be formed on the above-mentioned base layer 2 by a printing method such as gravure printing, letterpress printing, screen printing, transfer printing, flexographic printing, or inkjet printing.

There are no particular limitations on the design, and examples include letters, figures, symbols, patterns, etc.

It is preferable that the printing layer 2a is formed on one or both sides of the base layer 2, rather than on the outermost surface, to prevent damage to the pattern layer due to external impact.

The printing layer 2a may be an ink composition obtained by adding one or more of the following as the main component: one or more of ordinary ink vehicles; if necessary, one or more of plasticizers, stabilizers, antioxidants, light stabilizers, UV absorbers, curing agents, crosslinking agents, lubricants, antistatic agents, fillers, and other additives; and further adding colorants such as dyes and pigments; and thoroughly kneading the mixture with a solvent, diluent, etc. to prepare an ink composition. Examples of such ink vehicles include linseed oil, tung oil, soybean oil, hydrocarbon oil, rosin, rosin ester, rosin-modified resin, shellac, alkyd resin, phenolic resin, maleic acid resin, natural resin, hydrocarbon resin, polyvinyl chloride resin, polyacetic acid resin, polystyrene resin, polyvinyl butyral resin, acrylic or methacrylic resin, polyamide resin, polyester resin, polyurethane resin, epoxy resin, urea resin, melamine resin, aminoalkyd resin, nitrocellulose, ethyl cellulose, chlorinated rubber, cyclized rubber, and others, which can be used alone or in combination of two or more.

In addition, before printing, the substrate layer 2 can be subjected to a surface treatment such as a primer treatment or a corona treatment to improve ink adhesion.

Materials for the primer layer include, for example, non-curing or curing primer coating agents such as chlorinated polypropylene, ethyl-vinyl acetate, styrene-maleic acid, isocyanate, polyolefin, organic titanate, polyethyleneimine, polybutadiene, polyester, and acrylic.

The primer layer can be formed by coating using roll coating, gravure coating, knife coating, dip coating, spray coating, or other coating methods, drying the coating film to remove the solvent and diluent, and then performing aging treatment, etc., as necessary.

The gas barrier layer 4 is a layer that prevents the permeation of oxygen gas, water vapor, etc.

The gas barrier layer 4 may have a vapor deposition layer. The vapor deposition layer is preferably a layer made of one or more types of material selected from the group consisting of an aluminum vapor deposition film, an aluminum oxide vapor deposition film, and a silicon oxide vapor deposition film.

The deposition layer can be formed on the substrate film using the above-mentioned metal or inorganic oxide as a raw material, for example, by using a physical vapor deposition method (Physical Vapor Deposition method, PVD method) such as vacuum deposition method, sputtering method, ion plating method, cluster ion beam method, or a chemical vapor deposition method (Chemical Vapor Deposition method, CVD method) such as plasma chemical vapor deposition method, thermal chemical vapor deposition method, photochemical vapor deposition method, etc.

More specifically, in the above-mentioned PVD method, for example, a winding-type deposition machine is used, and the resin film coming off the unwinding roll in a vacuum chamber is placed in a deposition chamber, where the deposition source heated in a crucible is evaporated, and if necessary, a deposition layer is formed through a mask on the resin film on a cooled coating drum while oxygen or the like is blown out from an oxygen outlet, and then the resin film with the deposition layer formed thereon is wound up on a take-up roll, thereby producing a resin film having a deposition layer according to the present invention.

On the other hand, in the above-mentioned CVD method, a resin film on which a deposition layer of silicon oxide is formed by plasma can be produced by introducing a mixed gas of, for example, an organic silicon compound as a monomer gas, oxygen gas, and an inert gas supplied from a vapor deposition raw material volatilization supply device onto the surface of the resin film unwound from a winding roll arranged in the deposition chamber, on the peripheral surface of the electrode drum. In the present invention, the resin film having the above-mentioned inorganic oxide deposition layer prevents oxygen gas or water vapor, etc., contained in the tube container 20 from passing through, and functions as a barrier layer against these.

In the above, in order to obtain sufficient barrier properties, the thickness of the vapor-deposited layer is preferably from 5 to 300 nm, more preferably from 10 to 200 nm, and even more preferably from 10 to 100 nm.
More specifically, in the above PVD method, the thickness of the vapor-deposited layer made of aluminum oxide is preferably 20 to 100 nm, and more preferably about 30 to 50 nm.
In the above CVD method, the thickness of the vapor-deposited layer made of silicon oxide is preferably 5 to 50 nm, and more preferably 10 to 30 nm.
In the above, in the case of the deposition layer 60 made of a metal oxide or an inorganic oxide, if the thickness of the deposition layer exceeds 200 nm, cracks or the like are likely to occur in the deposition layer, and there is a risk that the barrier properties will decrease due to warping, and there are problems such as high material costs, which are undesirable. Also, if the thickness is less than 10 nm, it is undesirable because it becomes difficult to exhibit oxygen barrier properties.

In this embodiment, the gas barrier layer 4 may have a barrier coat layer below or above the deposition layer, thereby improving the oxygen barrier property and water vapor barrier property for the contents of the tube container.
When the resin film has a vapor-deposited film, the barrier coat layer may be provided on or under the vapor-deposited film.

In this embodiment, the barrier coat layer contains a barrier resin such as an ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol, polyacrylonitrile, polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide (MXD6), polyester, polyurethane, and (meth)acrylic resin. Among these, polyvinyl alcohol is preferred from the viewpoints of the oil barrier, oxygen barrier, and water vapor barrier properties of the contents of the tube container 20.
Furthermore, when the vapor-deposited film is made of an inorganic oxide, the occurrence of cracks in the vapor-deposited film can be effectively prevented by including polyvinyl alcohol in the barrier coat layer.

The content of the barrier resin in the barrier coat layer is preferably 50% by mass or more and 95% by mass or less, and more preferably 75% by mass or more and 90% by mass or less. By making the content of the barrier resin in the barrier coat layer 50% by mass or more, the oxygen barrier property and water vapor barrier property can be further improved.

The thickness of the barrier coat layer is preferably 0.01 μm or more and 10 μm or less, and more preferably 0.1 μm or more and 5 μm or less.
By setting the thickness of the barrier coat layer to 0.01 μm or more, the oxygen barrier property and water vapor barrier property for the contents of the tube container can be further improved.

The barrier coat layer can be formed by dissolving or dispersing the above-mentioned materials in water or a suitable solvent, applying the solution, and drying the solution. The barrier coat layer can also be formed by applying a commercially available barrier coat agent and drying the solution.

In another embodiment, the barrier coat layer is a barrier coating film containing at least one resin composition such as a hydrolysate of a metal alkoxide or a hydrolysis condensate of a metal alkoxide obtained by polycondensing a mixture of a metal alkoxide and a water-soluble polymer by a sol-gel method in the presence of a sol-gel catalyst, water, an organic solvent, and the like.
When the gas barrier layer 4 comprises a vapor-deposited film made of an inorganic oxide, the occurrence of cracks in the vapor-deposited film can be effectively prevented by providing the barrier coat layer of the above-mentioned form so as to be adjacent to the vapor-deposited film.

In one embodiment, the metal alkoxide is represented by the following general formula:
R ¹ _n M(OR ² ) _m
(In the formula, R ¹ and R ² each represent an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the atomic valence of M.)

As the metal atom M, for example, silicon, zirconium, titanium, aluminum, etc. can be used.
Examples of the organic group represented by R ¹ and R ² include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and an i-butyl group.

Examples of metal alkoxides satisfying the above general formula include tetramethoxysilane (Si( _OCH3 ) _{4 )} , tetraethoxysilane (mass %) Si( _{OC2H5 ) 4} ), tetrapropoxysilane (Si( _OC3H7 ) ₄ ), and _{tetrabutoxysilane} (Si( _OC4H9 ) ₄ ).

It is also preferable to use a silane coupling agent together with the metal alkoxide.
As the silane coupling agent, a known organoalkoxysilane containing an organic reactive group can be used, and in particular, an organoalkoxysilane having an epoxy group is preferred. Examples of organoalkoxysilane having an epoxy group include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

Two or more of the above silane coupling agents may be used, and it is preferable to use the silane coupling agent in an amount within the range of about 1 to 20 parts by mass per 100 parts by mass of the total amount of the alkoxide.

As water-soluble polymers, polyvinyl alcohol and ethylene-vinyl alcohol copolymers are preferred, and from the viewpoint of the oil barrier properties, oxygen barrier properties, water vapor barrier properties, water resistance and weather resistance of the contents, it is preferable to use these in combination.

The content of the water-soluble polymer in the barrier coating film is preferably 5 parts by mass or more and 500 parts by mass or less based on 100 parts by mass of the metal alkoxide.
By setting the content of the water-soluble polymer in the barrier coating film to 5 parts by mass or more per 100 parts by mass of the metal alkoxide, the oil barrier property, oxygen barrier property, and water vapor barrier property of the contents of the tube container can be further improved. Also, by setting the content of the water-soluble polymer in the barrier coating film to 500 parts by mass or less per 100 parts by mass of the metal alkoxide, the film formability of the barrier coating film can be improved.

The thickness of the barrier coating film is preferably 0.01 μm or more and 100 μm or less, and more preferably 0.1 μm or more and 50 μm or less, so that the oxygen barrier property and water vapor barrier property of the contents of the tube container 20 can be further improved.
By making the thickness of the barrier coating film 0.01 μm or more, the oxygen barrier property and water vapor barrier property of the contents of the tube container can be improved. Furthermore, when the barrier coating film is provided adjacent to a vapor deposition film made of an inorganic oxide, the occurrence of cracks in the vapor deposition film can be prevented.

The barrier coating film can be formed by applying a composition containing the above-mentioned materials by a conventionally known means such as roll coating using a gravure roll coater or the like, spray coating, dipping, brushing, bar coating, or an applicator, and then polycondensing the composition by a sol-gel method.
The sol-gel catalyst is preferably an acid or an amine compound. As the amine compound, a tertiary amine that is substantially insoluble in water and soluble in an organic solvent is preferable, and examples thereof include N,N-dimethylbenzylamine, tripropylamine, tributylamine, and tripentylamine. Among these, N,N-dimethylbenzylamine is preferable.
The sol-gel catalyst is preferably used in an amount of 0.01 part by mass to 1.0 part by mass, and more preferably 0.03 part by mass to 0.3 part by mass, per 100 parts by mass of the metal alkoxide.
By using the sol-gel catalyst in an amount of 0.01 part by mass or more per 100 parts by mass of the metal alkoxide, the catalytic effect can be improved.
Furthermore, by setting the amount of the sol-gel catalyst to 1.0 part by mass or less per 100 parts by mass of the metal alkoxide, the thickness of the formed barrier coating film can be made uniform.

The composition may further contain an acid, which is used as a catalyst in the sol-gel process, mainly for the hydrolysis of alkoxides, silane coupling agents, etc.
The acid may be a mineral acid such as sulfuric acid, hydrochloric acid, or nitric acid, or an organic acid such as acetic acid, tartaric acid, etc. The amount of the acid used is preferably 0.001 mol or more and 0.05 mol or less based on the total molar amount of the alkoxide and the alkoxide portion (e.g., silicate portion) of the silane coupling agent.
By using an amount of the acid that is 0.001 mole or more based on the total mole amount of the alkoxide and the alkoxide portion (eg, silicate portion) of the silane coupling agent, the catalytic effect can be improved.
Furthermore, by making the amount of the alkoxide not more than 0.05 moles relative to the total molar amount of the alkoxide and the alkoxide portion (eg, silicate portion) of the silane coupling agent, the thickness of the formed gas barrier coating film can be made uniform.

The composition preferably contains water in an amount of 0.1 mol or more and 100 mol or less, more preferably 0.8 mol or more and 2 mol or less, per mol of the total molar amount of the alkoxides.
By making the water content 0.1 mole or more per mole of the total molar amount of the alkoxides, the oil barrier property, oxygen barrier property and water vapor barrier property of the contents of the tube container 20 of the present invention can be improved.
Furthermore, by making the content of water 100 moles or more per mole of the total molar amount of the alkoxides, the hydrolysis reaction can be carried out quickly.

The composition may also contain an organic solvent. Examples of the organic solvent that can be used include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butanol.

Hereinafter, one embodiment of the method for forming a barrier coating film will be described.
First, a composition is prepared by mixing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and optionally a silane coupling agent, etc. A polycondensation reaction gradually proceeds in the composition.
Next, the composition is applied onto a substrate by the above-mentioned conventionally known method and dried. This drying process further advances the polycondensation reaction between the alkoxide and the water-soluble polymer (and the silane coupling agent, if the composition contains a silane coupling agent) to form a composite polymer layer.
Finally, the composition is heated at a temperature of 20 to 250° C., preferably 50 to 220° C., for 1 second to 10 minutes to form a gas barrier coating film.

The substrate layer that supports the deposited thin film can be made of the same material as substrate layer 2 described above.

The adhesive layer 8 is a layer for adhering the outer sealant layer 1, the base material layer 2, the heat insulating layer 3, the gas barrier layer 4, the inner sealant layer 5, etc. This adhesive layer can be appropriately selected depending on the resin that constitutes the layers to be adhered.

As the adhesive layer 8, any of the following can be used: anchor coating agents such as isocyanate-based (urethane-based), polyethyleneimine-based, polybutadiene-based, and organic titanium-based, or anchor coating agents such as polyurethane-based, polyacrylic-based, polyester-based, epoxy-based, polyvinyl acetate-based, cellulose-based, and other laminating adhesives, laminating adhesives, etc.

As the adhesive layer 8, for example, polyethylene, polypropylene, linear low-density polyethylene, ethylene-vinyl alcohol, ethylene-methacrylic acid copolymer, ethylene-acrylic acid copolymer, ionomer, maleic anhydride modified polyolefin resin, etc. can be suitably used.

In this embodiment, the thickness of the adhesive layer 8 is preferably 3 μm or more and 60 μm or less.

The outer sealant layer 1, the base layer 2, the heat insulating layer 3, the gas barrier layer 4, the inner sealant layer 5, etc. can be laminated by any method, such as wet lamination, dry lamination, solventless dry lamination, extrusion lamination, T-die co-extrusion molding, co-extrusion lamination, inflation, or any other method. When carrying out the above-mentioned lamination, if necessary, the film can be subjected to pretreatment, such as corona treatment or ozone treatment.

The packaging material 10 for tube containers may also have an intermediate layer between the gas barrier layer 4 and the inner sealant layer 5, if necessary. The intermediate layer is provided to adjust the thickness of the laminate sheet of the body tube. An olefin resin may be used for the intermediate layer. More specifically, it is preferable to use a polyethylene film such as low density polyethylene, linear low density polyethylene, or medium density polyethylene as the intermediate layer. The thickness of the intermediate layer is preferably, for example, 50 μm or more and 200 μm or less.

Next, we will explain the head member 40 of the tube container 20.

The head member 40 has a mouth portion 14 and a shoulder portion 13 provided below the mouth portion 14.

The mouth portion 14 has a threaded portion that is screwed into the cap 16.

The shoulder portion 13 has a shape in which the diameter gradually increases from the mouth portion 14 side toward the body portion 21 side. The shoulder portion 13 has a circular horizontal cross section.

The head member 40 is made of a resin material such as high-density polyethylene (HDPE). In addition to the high-density polyethylene, the head member 40 of the tube container 20 may also be made of an ethylene-α-olefin copolymer polymerized using a metallocene catalyst.

Next, the cylindrical body 21 will be described. The body 21 of the tube container 20 shown in Figure 3 has a generally cylindrical shape. This cylindrical body 21 is composed of a laminated tube container packaging material 10 (see Figures 1, 2(a), and 2(b)), and is obtained by rolling this tube container packaging material 10 into a cylindrical shape, overlapping opposing ends, and joining them together, for example, by heat sealing. Therefore, the body 21 has a heat seal section 12 in which laminate sheets are joined together along its longitudinal direction.

The thickness of the body 21 is preferably, for example, 300 μm or more and 500 μm or less, and more preferably 350 μm or more and 450 μm or less. By making the thickness of the body 300 μm or more, a predetermined strength can be maintained in the body of the tube container 20. This allows the body to maintain its independence and shape retention when the tube container 20 is placed upside down. In addition, by making the thickness of the body 350 μm or less, the manufacturing cost of the tube container packaging material 10 can be reduced, and moldability can be ensured when the head member is molded by compression molding.

Examples of heat sealing (welding) methods used in manufacturing the cylindrical body 21 of the tube container 20 include bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, and flame sealing.

In addition, in this embodiment, the head member 40 of the tube container 20 is joined to the cylindrical body 21 by thermal welding when the head member 40 is molded by compression molding. However, this is not limited to this, and the head member of the tube container 20 may also be joined to the cylindrical body by injection molding.

Next, referring to FIG. 6, a method for manufacturing the above-mentioned tube container 20 using compression molding will be described.

As shown in FIG. 6(a), this cylindrical body (body 21) is inserted into a mandrel 72, and a die 71 for compression molding the head member 40 is attached to one end of the mandrel 72. That is, the cylindrical body (body 21), which has been molded into a cylindrical shape in advance, is inserted into the mandrel 72, whose tip serves as a core for compression molding the head member 40, and is then advanced to a predetermined position into the cavity of the die 71 for molding the head member 40.

Then, the head member 40 is compression molded by supplying molten resin from a resin supply device into the mold 71. In this case, the head member 40 is molded by inserting the opening 21A at one end of the body 21 into the mold 71, and at the same time, the body tube 50 is fused integrally to the head member 40. The integrated head member 40 and body 21 are then removed from the mold 71 and mandrel 72 to obtain the tube container 20 shown in FIG. 6(b).

When manufacturing a tube container with a cap, the cap 16 is prepared in parallel with the production of the tube container 20. In this case, the cap 16 is produced by injection molding using, for example, an injection molding machine (not shown). The cap 16 is then screwed onto the mouth of the head member 40 of the tube container 20, thereby obtaining the tube container with a cap shown in FIG. 4.

In the present invention, the contents to be packed are filled into the opening at the bottom end of the tube container 20 manufactured as described above before it is completed, and then the opening is heat sealed to form a bottom weld, thereby producing the tube package (packaged product) 20A shown in Figure 5.

In the above, the contents to be filled and packaged can include, for example, frozen desserts such as ice cream and sherbet, soups, liquid foods such as nursing care foods, and others.

Next, we will explain a specific example of the above embodiment.

Example 1
First, a method for manufacturing the tube container will be described. The heat insulating layer 3 constituting the cylindrical body was a co-extruded inflation film (product name: Hanic, manufactured by Nichisei Chemical Industry Co., Ltd.) consisting of a foamed layer 3a (100 μm) with low density polyethylene as the base polymer and a non-foamed layer 3b (30 μm) made of linear low density polyethylene.

Next, a pattern printed layer 2a was formed by using a polyurethane-based gravure ink on the back surface of a 12 μm-thick biaxially oriented polyethylene terephthalate film for the base layer 2 constituting the trunk portion. Next, 4 g/m ² of a polyurethane-based adhesive for dry lamination was applied to the surface of the pattern printed layer 2a by a roll coating method, and after drying, the layer was laminated on the foamed layer side of the heat insulating layer 3. Next, a 12 μm-thick biaxially oriented polyethylene terephthalate film on which a 40 nm-thick aluminum vapor deposition film was formed was laminated as a gas barrier layer 4 on the non-foamed layer side of the heat insulating layer 3, and 4 g/m ² of a dry lamination adhesive was applied to the vapor deposition surface by a roll coating method, and after drying, a 180 μm-thick corona-treated linear low-density polyethylene (LDPE) film was laminated as an inner sealant layer 5 to obtain a laminated film.
Then, 4 g/ ^m2 of polyurethane adhesive for dry lamination was applied to the surface of the biaxially oriented polyethylene terephthalate film and dried, after which a 130 μm-thick low-density polyethylene resin (LDPE) film was laminated for the outer sealant layer 1 to obtain a raw sheet of laminate for forming the body portion having the following layer structure.

Outer sealant layer LDPE film (130μm) / Adhesive layer DL adhesive / Base layer PET film (12μm) / Picture print layer / Adhesive layer DL adhesive / Non-foamed layer LDPE (30μm) / Foamed layer (100μm) / Adhesive layer DL adhesive / Barrier layer silica-deposited PET film (12μm) / Adhesive layer DL adhesive / Inner sealant layer LDPE film (180μm)

Using the tube container packaging material 10 obtained above, one side edge portion and the other side edge portion were overlapped using a mandrel to form a cylindrical shape, and the back layer and front layer of the laminate at the overlapping portion were welded by a thermal welding method to obtain a cylindrical molded body.

Then, the head member 40 was integrally molded with this cylindrical molded body by compression molding to obtain the tube container according to Example 1 of the present invention. The head member 40 was made of high-density polyethylene (HDPE) to produce the tube container 20.

In parallel with the production of the tube container 20, the cap 16 was produced by injection molding. The resulting cap 16 was then screwed onto the mouth portion 14 of the head member 40 of the tube container to produce a tube container with a cap.

This tube container with a cap is a tube container suitable for storing contents such as frozen desserts such as ice cream and sherbet by providing an insulating layer including a foam layer on the outer surface of the tube container packaging material 10, and when the body of the tube container is pressed with the fingers of the hand, the fingers do not become extremely cold and the ice dessert can be removed from the opening.
Furthermore, by providing the non-foamed layer on the printed layer side, the surface was made smooth, and the appearance (appearance of the printing) of the tube container was excellent.

Example 2
A tube container 20 was produced by obtaining a tube container packaging material 10 in the same manner as in Example 1, except that a layer structure of a foamed layer 3a (60 μm) having low density polyethylene as a base polymer and non-foamed layers 3b and 3c (20 μm) made of linear low density polyethylene and a co-extruded inflation film (product name: MS-624CX, manufactured by Idemitsu Unitech Co., Ltd.) of non-foamed layer (20 μm)/foamed layer LDPE (60 μm)/non-foamed layer (20 μm) were used as the heat insulating layer 3. The layer structure of the tube container packaging material 10 is as follows.

Outer sealant layer LDPE film (130μm) / Base material layer PET film (12μm) / Picture print layer / Adhesive layer DL adhesive / Non-foamed layer (20μm) / Foamed layer LDPE (60μm) / Non-foamed layer (20μm) / Adhesive layer DL adhesive / Barrier layer silica-deposited PET film (12μm) / Adhesive layer DL adhesive / Inner sealant layer LDPE film (180μm)

(Comparative Example 1)
A laminate for a tubular container was obtained and a tubular container was produced in the same manner as in Example 1, except that the heat insulating layer of Example 1 was not provided. The layer structure of the laminate for a tubular container was as follows.

Outer sealant layer LDPE film (130 μm) / Base material layer PET film (12 μm) / Picture print layer / Adhesive layer DL adhesive / Barrier layer silica vapor deposition PET film (12 μm) / Adhesive layer DL adhesive / Inner sealant layer LDPE film (180 μm)

[Surface temperature and finger measurement]
The tube containers obtained in Examples 1 and 2 and Comparative Example 1 were filled with water and stored in a freezer with an internal temperature of -30°C for 24 hours. The surface temperature of the body of the tube container immediately after removal from the freezer and the finger temperature when holding the tube container in the hand were measured at room temperature (25°C) for 1 minute using a thermography Thermo Shot 30W (manufactured by NEC Avio Infrared Technology).

<Evaluation criteria>
Products that had an effect of suppressing the perceived temperature were given a result of "〇" (good), and products that did not have an effect of suppressing the perceived temperature were given a result of "×" (bad).
It was decided.

As shown in Table 1, the tube containers produced in Examples 1 and 2 had a surface temperature of 8°C or higher 60 seconds after being removed from the freezer, and a finger temperature of 18°C or higher. The tube container produced in Comparative Example 1 had a surface temperature of 8°C or lower 60 seconds after being removed from the freezer, and a finger temperature of 15°C or lower.

In other words, the tube containers of Examples 1 and 2 had superior insulation properties compared to Comparative Example 1.

1 Outer sealant layer 2 Base material layer 2a Printed layer 3 Heat insulating layer 3a Foamed layer 3b Non-foamed layer 3c Non-foamed layer 4 Gas barrier layer 5 Inner sealant layer 8 Adhesive layer 10 Tube container packaging material 11, 11' Pair of bonded ends 12 Heat seal portion 13 Shoulder portion 14 Mouth portion 16 Cap 17 Contents 18 Bottom seal portion 20 Tube container 20A Packaged product 21 Cylindrical body portion (body portion)
21A Opening 40 Head member 71 Mold 72 Mandrel

Claims (5)

A packaging material for a tube container having a pair of bonded ends,
The insulating sheet includes at least an outer sealant layer, a base layer, a printed layer, a heat insulating layer, and an inner sealant layer, which are arranged in this order from the outer surface to the inner surface,
The insulating layer includes a foam layer,
The porosity of the foam layer is 30% by volume or more and 70% by volume or less,
The heat insulating layer further includes a non-foamed layer on the base layer side,
The packaging material for tube containers has a thickness of 300 μm or more and 500 μm or less . 2. The packaging material for tube containers according to claim 1 , wherein the heat insulating layer comprises a non-foamed layer on one or both sides of the foamed layer. The packaging material for tube containers according to claim 1 or 2 , wherein the base layer is printed. The packaging material for a tube container according to claim 1 , further comprising a gas barrier layer. A cylindrical body portion formed by overlapping and joining opposing ends of the packaging material for tube containers according to any one of claims 1 to 4 ,
A tube container comprising a head member joined to one end of the cylindrical body portion.