JPH072196Y2 - Multi-layer container with excellent storability of contents - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a multi-layer container which is excellent in preventing discoloration and deterioration of contents such as foods. More specifically, by providing a partially coated surface on the inner surface of the container, tin elution amount can be controlled and molded. TECHNICAL FIELD The present invention relates to a multi-layer container in which the container is prevented from becoming dirty.

[0002]

2. Description of the Related Art Conventionally, a so-called container with a peelable seal lid has been known as a container having both sealing property and easy opening property. This peelable container is a heat-seal lid that consists of a flanged container formed by drawing a laminated body in which a thermoplastic resin film is laminated on both sides of a metal foil, and a flexible substrate in which a thermoplastic resin film is laminated on both sides of a metal foil. The foodstuffs are usually filled with food as the contents, and the heat-sealing lid is sealed and then heat sterilization is performed.

Even if the container having excellent sealing property and gas barrier property is sterilized by heating after filling the contents, if the storage period becomes long, oxygen remaining in the container after sealing, oxygen existing in food or food There is a problem that the active enzyme causes the food to be discolored or the flavor (flavor) is impaired by oxidation.

As a solution to such a problem, the present inventors have proposed a container having an exposed tin layer on the inner surface of the container (Japanese Patent Application No. 1-116190, Japanese Patent Application No. 2-5).
2675). In these devices, the tin layer exposed on the inner surface of the container captures residual oxygen and the like in the container to prevent discoloration and deterioration of the contents.

[0005]

Although the above-mentioned container is sufficiently satisfactory in terms of the storability of the contents, since the tin layer is exposed, the inner tin layer is scraped off by a punch during drawing. Stains may occur. Further, depending on the exposed amount of the tin layer, there may be a case where more than the amount of tin necessary for capturing the residual oxygen and the like is eluted, and these points are not yet sufficiently satisfactory.

Therefore, the object of the present invention is to prevent contamination during molding and elution of more than necessary amount of tin, and at the same time, to provide a sealing property and an easy opening property which are excellent in preventing discoloration and deterioration of the contents. In order to provide a multi-layer container having.

[0007]

According to the present invention, a laminate of a thermoplastic resin film and a tin foil is formed, and the resin film is formed by drawing so that the outer surface side and the tin foil foil are on the inner surface side and the bottom portion, respectively. A seamless container with a flange, the tin layer of which is exposed on the inner surface, a flexible lid composed of a laminate of a gas barrier substrate and a resin protective layer covering the inner and outer surfaces thereof, a flange upper surface and an inner lid surface. In a multi-layer container comprising a seal portion formed by heat sealing via an acid-modified olefin resin layer interposed between, the flanged seamless container has a portion corresponding to the inner surface of the flange and the side wall portion of the acid-modified olefin. Make sure that the inner wall of the cup side wall is completely covered with the acid-modified olefin resin in a laminate blank that has been pre-coated with resin in a donut shape and the portion corresponding to the inner surface of the bottom is unpainted. Excellent multilayer container storage stability of those formed by drawing contents are provided.

[0008]

[Operation] In the multi-layer container of the present invention, the seamless container with a flange is pre-painted with an acid-modified olefin resin on the portions corresponding to the inner surfaces of the flange portion and the side wall portion, and the portion corresponding to the inner surface of the bottom portion is unpainted. It is characterized in that it is drawn from a laminate blank.

That is, in the present invention, by exposing a certain amount of tin layer on the inner surface of the container, residual oxygen in the container and active enzymes contained in the content are captured by the reducing action of tin, and It is possible to prevent the oxidative deterioration of the. Therefore, the flavor (flavor) retention of the contents is extremely good, and even if there is a risk that the tin foil may be corroded by the ingredients depending on the food, the elution of iron can prevent the elution of iron, so the flavor retention is maintained. Can be held satisfactorily.

As described above, when the exposed area of tin on the inner surface of the container is large, the elution of tin exceeds the required amount, which is not preferable, but in the present invention, the exposed layer of tin is formed only on the portion corresponding to the bottom of the inner surface of the container. Since the amount is limited, the amount of tin eluted can be adjusted to the amount required for the reducing action.

In drawing forming for forming a laminated body blank into a container, it is the portion corresponding to the inner surface of the side wall of the container that is rubbed by the movement of the punch. In the present invention, this portion is acid-modified olefin. Since the resin is pre-painted, the tin layer is not scraped off by the punch, and the container and the punch are prevented from being soiled.

In the container of the present invention, since the acid-modified olefin resin is also applied to the flange portion where the lid is to be sealed, the container is excellent in heat sealing property, sealing property and easy opening property. It is possible. Furthermore, since the container body is made of a laminate obtained by laminating a resin film on a tin foil having excellent gas barrier properties, and the lid is also made of a gas barrier substrate having protective resin layers on the inner and outer surfaces,
The container body is also excellent in gas barrier property, and also in this respect, excellent preservability of the contents is secured.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described with reference to the accompanying drawings. In FIG. 1 and FIG. 2 (“FIG. 2” is an AA cross section of FIG. 1) showing a plan view and a side sectional view of an example of the multilayer container of the present invention, the container body 1 has a bottom portion 3. , Side wall 4
And flange portion 5, and is seamlessly formed by drawing. In this container body 1, the upper surface of the flange portion 5 and the inner surface of the lid body 2 are joined together to form a seal portion 7, which is hermetically sealed.

In FIG. 3 and FIG. 4 which are enlarged views of the B portion (side wall portion) and C portion (bottom portion) of FIG. 2, the side wall portion 4 of the container body 1 is the inner surface side of the container. It is composed of an acid-modified olefin resin 6, a tin foil 9 serving as an intermediate layer, and a thermoplastic resin film 10 on the outer surface side. In the bottom portion 3, from the tin foil foil 9 serving as the inner surface side of the container and the thermoplastic resin film 10 on the outer surface side. Made of In the tin foil 9 shown in the figure, the tin layers 12 are provided on both surfaces of the steel layer 11, but it is also possible to use one having a tin layer on only one side of the steel layer 11.

In "FIG. 5" which is an enlarged view of the portion D (flange portion) of "FIG. 2", the lid 2 has a gas barrier substrate 13 and a resin protective layer for covering the inner and outer surfaces thereof as shown in the figure. It is made of a laminate of 14 and 15 and is flexible. The flange portion 5 of the container body 1 has a laminated structure that is continuous from the side wall portion 4. The upper surface side to be joined to the lid body 2 is an acid-modified olefin resin 6, the tin foil 9 as an intermediate layer, and the outer surface side is a thermoplastic resin film. It consists of 10. The inner surface protective resin layer 14 of the lid 2 is joined to the container flange portion by heat sealing via the acid-modified olefin resin layer 6 to form the seal portion 7.

(Molding of Container Main Body) In molding the container main body in which the tin layer of the tin foil is exposed only at the bottom as described above, as shown in FIG. 6, a thermoplastic resin film on the outer surface side of the container is used. The tin-foil laminate blank 16 is coated with the acid-modified olefin resin 6 in a donut shape on the tin foil side in advance so as to correspond to the side wall portion and the flange portion of the container, and the coated laminate blank is subjected to drawing. By doing so, it can be easily molded. A laminated body blank is usually prepared by applying a bonding primer to a laminated surface of a thermoplastic resin film and drying it, and heating a tin foil by heating and pressing it through a laminating roll and then cooling. Further, the seamless container formed by drawing is subjected to flange processing, the peripheral edge portion of the flange is curled in the next step, and the curled portion is further lowered from the sealing surface.

(Tin Plate Foil) The tin plate foil 9 is not limited to the one shown in the figure in which both surfaces of the steel layer 11 are provided with the tin layers 12, but one having a tin layer on only one side of the steel layer 11 is used. You can also In this case, the thermoplastic resin film serving as the outer surface layer of the container is applied to the steel layer side.

The thickness of the tin foil is preferably 20 to 200 μm, particularly preferably 35 to 150 μm. The tin layer covering the steel layer is tin 2.5 to 25 g / m
Those in the range of ^ 2 can be preferably used.

(Thermoplastic resin film) The thermoplastic resin film used on the outer surface side of the container body is
Olefin resin such as polypropylene, polyethylene, propylene-ethylene copolymer, propylene-ethylene-butene copolymer, ethylene-1-butene copolymer, ethylene-acrylate copolymer, polyolefin / ionomer; polyethylene terephthalate, polytetra Methylene terephthalate, polyethylene terephthalate /
Polyester resin such as isophthalate copolymer, polyethylene / butylene terephthalate copolymer, polyethylene naphthoate; nylon 6, nylon 6,6, nylon 6 / nylon 6,6 copolymer, nylon 12, nylon 11, nylon 6, Polyamide resins such as 6 / nylon 610 copolymer and nylon 6 / nylon 11 copolymer.

Any of crystalline, partially crystalline and amorphous materials can be used, but crystalline and partially crystalline materials can be preferably used. It is also possible to contain pigments, colorants, light and heat stabilizers, flame retardants, lubricants and the like.

Particularly preferred resin films in terms of performance and economy are polypropylene film and polyester film. The thickness of the thermoplastic resin film is preferably 5 to 100 μm, particularly preferably 15 to 80 μm.

(Acid-modified olefin resin) The acid-modified olefin resin provided on the inner surfaces of the side wall portion and the flange portion of the container body is an olefin resin graft-modified with an acid or an acid anhydride or a dispersion of this modified olefin resin. An organic paint layer can be mentioned.

Specifically, olefin resins such as polypropylene, propylene-ethylene copolymer, polyethylene, etc., and ethylene-based resins such as maleic anhydride, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, etc. An unsaturated carboxylic acid or an anhydride thereof is graft-polymerized, and a carboxyl group-based carbonyl group concentration of 5 to 700 mmol / 100 g resin, particularly 10 to 500 mmol / 100 g resin can be preferably used. .

The acid-modified olefin resin is usually applied to the tin foil side of the laminate of the thermoplastic resin and the tin foil, which is the outer surface side of the container, in the form of an organosol by coating and drying, or a resin film. Can be heat-fused for coating, or hot-melt resin can be fusion-coated for coating.

The thickness of the acid-modified olefin resin is 1 to 20.
It is about μm. Further, the acid-modified olefin resin is used as an epoxy-phenol resin-based coating, an epoxy-amino resin-based coating, an epoxy-acrylic resin-based coating, an epoxy-
It is also possible to use one dispersed in a vinyl resin-based paint. In this case, the acid-modified olefin resin is preferably used in an amount of 2 to 50% by weight, particularly 1 to 20% by weight based on the solid content of the primer.

(Lid) The gas barrier substrate used for the material of the lid is a metal foil such as aluminum foil, steel foil, tin foil, and stainless steel foil,
Saponified ethylene-vinyl acetate copolymer, polyvinylidene chloride copolymer, m-xylylene adipamide (MXD
6 Nylon), SELARPA (a product of DuPont, trade name), polyacrylonitrile, liquid crystal polyester, aramid (whole aromatic aromatic nylon), and the like, which are excellent in gas barrier properties.

When the lid is required to be transparent, a resin film is used. The thickness of the gas barrier substrate varies depending on the material and purpose of use, but is usually 5 to 50 μm.
Used.

As the protective resin layer coating the inner and outer surfaces of the gas barrier substrate, a heat sealable thermoplastic resin is used. For example, the same as the above-mentioned thermoplastic resin and acid-modified olefin resin or a combination thereof can be used.

Further, as the protective resin layer on the outer surface side, a coating film such as paint or printing paint can be used. Examples of the coating film include phenol formaldehyde resin, furan-formaldehyde resin, xylene-formaldehyde resin, ketone-formaldehyde resin, urea formaldehyde resin, melamine-formaldehyde resin, alkyd resin, unsaturated polyester resin, epoxy resin, bismaleimide resin. , Thermoallyl paints such as triallyl cyanurate resin, thermosetting acrylic resin, silicone resin, oily resin; or vinyl chloride-vinyl acetate copolymer,
Vinyl chloride-vinyl acetate copolymer partially saponified product, vinyl chloride-maleic acid copolymer, vinyl chloride-maleic acid-
Examples thereof include thermoplastic resin coatings such as vinyl acetate copolymers, acrylic polymers, and saturated polyester resins.
These resin paints may be used alone or in combination of two or more.

The coating of the resin protective layer on the gas barrier substrate is carried out by laminating a resin film, and an adhesive primer can be used if necessary. When coating with a paint, the protective layer is formed by heating and drying after coating.

The lid is made by punching out a laminate having a gas barrier substrate and a resin protective layer covering the inner and outer surfaces thereof into a predetermined shape and size. Further, a so-called easy open lid can be obtained by using a metal foil for the gas barrier substrate of the lid and performing score processing and attachment processing of the opening tab on the metal foil.

To seal the lid and the container body, after filling the container body with the contents, cover the lid body and heat the acid-modified olefin resin to a temperature above its softening point with a heat sealing device such as high frequency induction heating. By heating and heat sealing, a seal portion is formed by adhesively bonding the inner surface of the lid and the upper surface of the flange portion through the acid-modified olefin resin,
The multi-layer container of the present invention is formed.

[0033]

EFFECTS OF THE INVENTION According to the present invention, a laminate blank in which the inner surface of the flange and the side wall of the container body is pre-painted with an acid-modified olefin resin and the inner surface of the bottom is unpainted. It is possible to prevent stains and elution of tin in excess of the required amount during molding by forming by drawing, while the reducing action of tin exposed at the bottom of the container reduces residual oxygen and contents in the container. It is possible to prevent the oxidative deterioration of the content by trapping the active enzyme and the like contained in the, and thus it is possible to provide a multi-layer container having an extremely excellent flavor (flavor) retention of the content.

[0034]

[Example] Example 1 Tin foil (tin plating amount: 11 g / m ^ 2, thickness: 75 μm)
A maleic anhydride-modified polypropylene-ethylene copolymer (average carbonyl group concentration 40 meq / 100 g polymer, melting point 170 ° C., MI50) was dispersed in an epoxyphenol paint for 10 phr to obtain an outer diameter of 130 m.
m and an inner diameter of 50 mm were applied in a donut shape and heated and baked. Then on the backside tin foil of the primer,
Laminate a polypropylene film containing titanium white (thickness 40 μm) via a urethane resin primer,
Then, aging was performed at 50 ° C. to prepare a resin film laminated tin foil having a donut-shaped primer layer on one surface. Using this as a material, a seamless cup-shaped container with a flange having a resin film side as an outer surface, a center unpainted portion of a donut-shaped primer as an inner surface bottom portion, and a diameter of 50 mm was continuously prepared using a press molding machine. (Container A).

Similarly, on the surface to be the inner surface of the container, the outer diameter is 130 mm and the diameter of the unpainted portion is 70, 90, respectively.
The primer was applied in a donut shape so that it was 100 mm, which was larger than the diameter of the bottom surface of the container, and an unpainted portion was formed on the side wall of the container. This material was used to continuously produce containers with a bottom diameter of 50 mm (container B,
C, D).

The contents were filled with mushrooms and a seasoning liquid consisting of salt, citric acid and ascorbic acid, and a lid member made of polypropylene / adhesive / aluminum foil / adhesive / polypropylene was heat-sealed. Heat sterilize this mushroom-containing container at 115 ° C for 45 minutes,
Then, after storing at 35 ° C., the storability of the contents and the amount of tin in the contents were measured at regular intervals. In addition, the results of examining the stains on the container and punch during container production are also shown.

As is clear from the table, all containers were excellent in terms of storage stability of the contents, but as the side wall of the container was covered with the primer, the tin elution amount decreased and the molding punch,
The container is also clean.

[0038]

[Table 1] * Number of products produced until stains occur

Example 2 In the same manner as in Example 1, an organosol of polypropylene-maleic anhydride-ethylene copolymer (solid content: 10) was used.
%) Outer diameter 130 mm, inner diameter 50 mm and 100 mm
From the doughnut-shaped resin film-laminated tin foil, a seamless cup-shaped container with a flange in which the central unpainted portion of the donut-shaped primer was the inner bottom was continuously prepared using a press molding machine (containers E and F). Similarly, mushrooms and seasonings were filled and sterilized at 115 ° C. for 45 minutes. The storability of the contents and the amount of tin elution were measured at regular intervals. Table 2 also shows the results of examining the stains on the container and the punch at the time of container production.

[0040]

[Table 2] * Number of products produced until stains occur

[Brief description of drawings]

FIG. 1 is a plan view of an example of a multi-layer container of the present invention.

FIG. 2 is an AA cross section of “FIG. 1”.

FIG. 3 is an enlarged view of portion B of “FIG. 2”.

FIG. 4 is an enlarged view of a portion C of “FIG. 2”.

FIG. 5 is an enlarged view of a portion D of “FIG. 2”.

FIG. 6 is a view showing a laminated body blank for producing the container body of the present invention.

[Explanation of sign]

1 is a container main body, 2 is a lid, 3 is a bottom part, 4 is a side wall part, 5 is a flange part, 6 is an acid-modified olefin resin layer, 9 is a tin foil, 10 is a thermoplastic resin film, and 12 is a tin layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Yunori Yamaguchi 5-7-37, Aizawa, Seya-ku, Yokohama-shi, Kanagawa (56) References

Claims (1)

[Scope of utility model registration request] 1. A flange comprising a laminate of a thermoplastic resin film and a tin foil, wherein the resin film is drawn so that the outer surface side and the tin foil are on the inner surface side, and the tin layer is exposed on the inner surface of the bottom portion. A seamless container, a flexible lid composed of a laminated body of a gas barrier substrate and a resin protective layer covering the inner and outer surfaces thereof, and an acid-modified olefin resin layer interposed between the upper surface of the flange and the inner surface of the lid. In a multi-layer container consisting of a seal portion formed by heat sealing via
In the seamless container with a flange, a portion corresponding to the inner surface of the flange and the side wall portion is previously coated with an acid-modified olefin resin in a donut shape, and a portion corresponding to the inner surface of the bottom portion is unpainted. A multi-layer container which is formed by drawing so that the inner surface is completely covered with the acid-modified olefin resin and which has excellent storage stability of the contents.