JPH032754B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention exhibits excellent sealing performance for a long period not only for powder contents but also for liquid contents,
Boil sterilization or retort sterilization is possible,
This invention relates to a material for a sealed package that is easy to open.

Prior Art Conventionally, liquid or fluid contents such as alcoholic beverages, juices, dressings, mayonnaise, jams, etc. are stored in ceramic containers (herein simply referred to as glass containers) such as glass containers, and are held with metal or plastic screwdrivers. Although it is sealed by a cap, it has the disadvantage that it is very difficult to open and is expensive. Another method is to caulk an aluminum plate to the opening of the glass container and seal it, but this method is difficult to open and is also expensive.
Some glass containers for storing powders such as instant coffee and powdered cream are heat-sealed and sealed using a laminated material such as aluminum foil or paper that has been coated with a heat-sealing agent. When the container is used as a sealed package for a liquid or fluid, there is a drawback that the adhesive strength of the heat-sealed portion decreases significantly within a short period of time due to contact with the contents, resulting in peeling. Japanese Patent Publication No. 53-8273 discloses a technique of coating the open end surface of a glass container with silane as an adhesion aid layer, but this method also has problems.
That is, if the coating thickness of the adhesion auxiliary material is not sufficient, uniform heat sealing will be difficult due to unevenness of the opening of the glass container, variations in parallelism, etc., and if the coating thickness is made sufficiently large, the cost will be significant. It gets really expensive. Furthermore, after filling and sealing the contents in a glass container, boiling sterilization or retort sterilization is performed, but in this case as well, it is necessary to use a glass container and lid material that can sufficiently withstand sterilization treatment at high temperatures. At present, it is difficult to obtain a combination.

Purpose of the Invention Therefore, the purpose of the present invention is to exhibit excellent sealing properties even for liquid contents over a long period of time, to enable boiling sterilization at high temperatures, to be easy to open, and to maintain the sealability after opening. To provide a combination of a glass container and a lid material for a sealed package whose opening part of the glass container has a beautiful appearance.

Structure of the Invention As a result of various studies while keeping in mind the current state of the technology as described above, the present inventor formed a specific resin layer on the opening end surface of the glass container and the lid material, respectively.
When combining these two into a sealed package,
The present inventors have discovered that the above objects can be fully achieved, and have finally completed the present invention.

In the glass container and lid material constituting the sealed package material of the present invention, a resin layer consisting of (a) or (b) shown below is formed. In this case, one of the two resin layers is made up of (a), and the other one is made up of (b).

(A): An ionomer alone or a mixed resin of an ionomer and at least one selected from the group consisting of polyolefin, ethylene copolymer, styrene graft copolymer, polyester, acrylic resin, and epoxy resin.

More specific examples of these resins are as follows.

Ionomer...The anion part of the ionic bond (crosslinking) is 3 carbon atoms such as acrylic acid, methacrylic acid, ethacrylic acid, itaconic acid, maleic acid, etc.
~8 unsaturated carboxylic acids are used. The cation part includes Na ⁺ , K ⁺ , Mg ⁺⁺ , Zn ⁺⁺ , Li ⁺ ,
Cs ⁺ , Ag ⁺ , Cu ⁺ , Be ⁺⁺ , Ca ⁺⁺ , Sr ⁺⁺ , Ba ⁺⁺ ,
Cu ⁺⁺ , Cd ⁺⁺ , Sn ⁺⁺ , Pb ⁺⁺ , Fe ⁺⁺ , Co ⁺⁺ ,
Examples include mono- to trivalent metal ions such as Ni ⁺⁺ , Al ⁺⁺ , Sc ⁺⁺ , and Fe ⁺⁺ .

Polyolefin: polyethylene such as linear polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene,
Polybutene-1, polybutylene, polymethylpentene, etc.

Ethylene copolymer...ethylene-ethyl acrylate copolymer, ethylene-isobutyl acrylate copolymer, ethylene-acrylic acid copolymer,
Ethylene-methacrylic acid copolymer, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc.

Styrene graft copolymers: styrene-grafted polyethylene, styrene-grafted polypropylene, styrene-grafted ethylene-vinyl acetate, etc.

Polyester: Linear copolymerized polyester resin is mainly used. This is because 95 to 50 mol% of the acid component is terephthalic acid residue, and the glycol component is
20 to 70 mol% consists of ethylene glycol residues, and the remaining 5 to 50 mol% of the acid components are adipic acid, sabacasic acid, other aliphatic dibasic acids, isophthalic acid, orthophthalic acid, diphenyldicarboxylic acid. The remaining 80 to 30 mol% of the glycol component consists of residues of aromatic dibasic acids such as 1,2-
It consists of glycol residues such as propylene glycol, 1,3-propylene glycol, dipropylene glycol, and neopentyl glycol.

Acrylic resin...polymethyl methacrylate,
polyethyl methacrylate, polyacrylate,
Methyl methacrylate-α-methylstyrene copolymer, etc.

Epoxy resin: Epoxy resins with a molecular weight of about 400 to 10,000 containing so-called epoxy resin curing agents such as amines, polyamides, acid anhydrides, phenolic resins, butylated melamine formaldehyde resins, butylated urea formaldehyde resins, etc. are preferred.

(b) Polyethylene alone or polyethylene and at least one member selected from the group consisting of polyolefin (excluding polyethylene that is the same as the polyethylene), ethylene copolymer, styrene graft copolymer, polyester, acrylic resin, and epoxy resin. mixed resin.

Specific examples of resin (b) are the same as in (a).

According to the research of the present inventor, the diameter of the glass container,
Although it varies depending on the width of the heat-sealed part, the structure of the lid material, etc., it is possible to easily open the container and to make the appearance of the opening of the glass container beautiful after opening by breaking the interface between both resin layers. The adhesive strength after 90° peeling is about 0.8 to 3.0 kg/15 mm width, preferably 1.0
~2.5Kg/15mm width is desirable. Generally, in order to reduce the adhesive strength between an ionomer and polyethylene, polypropylene, polyester, acrylic resin, or
It is effective to mix epoxy resin, etc., and conversely, in order to improve the adhesive strength between the ionomer and polyethylene, polyethylene for one or both of the two,
Mixtures of ethylene copolymers, styrene graft copolymers, etc. are effective.

In addition, in order to improve heat resistance during boil sterilization (usually at 80 to 95°C for about 30 minutes), ionomers include polyethylene such as linear polyethylene, low density polyethylene, medium density polyethylene, and high density polyethylene, polypropylene, It is effective to add polyester, acrylic resin, epoxy resin, etc., and to polyethylene, it is effective to add polyethylene, polypropylene, etc. that are different from the polyethylene.

Therefore, if you consider the ease of opening, the beauty of the opening of the glass container after opening, the heat resistance during boil sterilization, etc., when adding and mixing other resins to ionomer or polyethylene, it is necessary to It is suitable that the amount of solids is up to about 80% by weight of the total resin weight, more preferably about 10 to 60% by weight.

In addition, in order to improve the adhesion of the resin layer itself consisting of (a) or (b) above to the glass container, about 0.1 to 20% by weight of a silane coupling agent (both as solid content) is added to the resin layer. May be added. Such silane coupling agents include γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyl-
Tris-β-methoxyethoxysilane, γ-methacryloxypropyltrimethoxysilane, β-
3,4-epoxycyclohexylethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-
Examples include mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-β-aminoethoxy-γ-aminopropyltrimethoxysilane. Alternatively, the above-mentioned silane coupling agent layer may be formed as a primer layer to a thickness of 0.1 to 1 μm on the upper end surface of the opening of the glass container, and the resin layer consisting of (a) or (b) above may be formed thereon. good.

The present invention will be described in more detail below with reference to embodiments of the present invention shown in the drawings.

In FIG. 1, a resin layer 3 is provided on the upper end surface of the opening of the glass container body 1. As shown in FIG. The resin layer 3
The thickness is determined by taking into account the unevenness of the upper end surface of the opening, variations in parallelism, etc., but even under optimal conditions, it is required to be 1 μm or more, and preferably 3 to 10 μm.
degree. However, if the upper end surface of the opening has large irregularities, the thickness may be approximately 400 μm.
Although it is possible to use a thickness greater than this, no particular improvement in effectiveness is observed.

The glass container of the present invention of the type shown in FIG. 1 can be obtained by applying the above-mentioned resin (a) or (b) to the open end surface of the glass container, for example, during the slow cooling process of the glass container immediately after molding.
Temperature suitable for each resin, e.g. about 80~250℃,
It is manufactured by baking preferably at about 100 to 200°C for about 5 seconds to 10 minutes, preferably about 10 seconds to 5 minutes. Alternatively, a glass container at room temperature after molding may be heated to preferably about 80 to 100°C, the resin resin (a) or (b) may be applied to the open end surface of the container, and then baked in the same manner as described above. good.

FIG. 2 shows a glass according to the invention in which a silane coupling agent layer 5 is provided as a primer layer on the upper end surface of the opening of the glass container body 1, and a resin layer 3 made of resin (a) or (b) is formed thereon. Indicates the container. In this way, the adhesion between the resin layer 3 and the glass container body 1 is further strengthened.

In the glass container of the present invention having the type shown in FIG. 2, for example, during the slow cooling process of the glass container after molding, about 50% of the silane coupling agent is applied to the open end surface of the glass container.
Apply ~10% solution, dry at 100 to 200℃ for 5 to 60 seconds if necessary, and then apply the above resin (a) or (b).
and apply at a temperature suitable for each resin, e.g.
It is manufactured by baking at ~250°C, preferably about 100~200°C for about 5 seconds to 10 minutes, preferably about 10 seconds to 5 minutes. Alternatively, a molded glass container at room temperature is preferably heated to about 80 to 100°C, and the silane coupling agent is applied and dried, and the resin (a) or (b) is applied and baked under the same conditions as above. You can also do that.

Application of resin, silane coupling agent, or a mixture of both to the open end surface of a glass container is as follows:
For example, this can be easily carried out by bringing a sponge roll, rubber roll, sponge sheet, etc. impregnated with these materials into contact with the open end surface.

The base material of the lid material itself for sealing the above-mentioned glass container to form a predetermined sealed package is aluminum foil, which is similar to that used as the base material of the lid material of conventional sealed packages for powder. Plastic film, paper, or a laminate thereof may be used, and although detailed description thereof will not be given, an example thereof is as follows. As shown in FIG. 3, the lid material is made of aluminum foil, polyester film, paper, and laminates of these materials, as well as laminates of aluminum foil and polyolefin film such as polyethylene, and polyester film.
A resin layer 9 similar to the resin layer 3 of the glass container is provided on a base material 7 such as a laminate of polyolefin film such as polyethylene. However, when either one of both resin layers is resin (a), the other is resin (b). The thickness of the resin layer 9 is desirably 4 .mu.m or more in order to obtain a uniform seal, and for economical reasons, the upper limit is preferably about 60 .mu.m. The resin layer 9 may be formed directly on the base material 7, but a film of resin (a) or (b) may be formed by, for example, a dry lamination method using a urethane adhesive, or an organic titanate or urethane anchor coating agent. The substrate 7 may be bonded to the base material 7 by a polyethylene extrusion lamination method using a polyethylene extrusion lamination method or the like. In addition, as for the lid material, printing layer 1 is added as usual.
1. An overcoat 13 etc. can be provided as necessary.

Incidentally, the glass container used in the present invention may be coated with a metal oxide film in a conventional manner. That is, in the normal glass container manufacturing process, the diameter of the glass container exiting the forming station,
i.e. 300 ml in a glass container at the hot end.
By spraying a solution of a metal compound such as tin tetrachloride at a temperature of ~600°C, an extremely thin film of metal oxide such as tin oxide is formed into the network structure of the glass, improving the mechanical strength of the glass container. and improved chemical stability. According to research conducted by the present inventors, it has been found that the presence of such a metal oxide film does not have any effect on the performance of the sealed package.

In order to manufacture the sealed package of the present invention, the above-mentioned glass container is sterilized, filled with contents, and then the lid material is heat-sealed in a conventional manner at 170°C to 220°C for 1 second. Just do it. When filling the contents following the resin drying process described above,
It can also be used to sterilize glass containers. Filling methods include aseptic filling, jam at about 90-95℃,
A hot pack method for filling with alcohol or the like can be arbitrarily adopted. When a hot pack method is adopted following the drying process, it is possible to reduce the increase in internal pressure due to the expansion of air in the head space after packaging, thereby reducing sealing defects. or,
When the hot pack method is employed, the effect of lowering the heat sealing temperature and shortening the heat sealing time is also achieved. The glass container and the lid can be heat-sealed by a known heating method such as heating with a hot plate or high-frequency induction heating. The sealed package after heat sealing is subjected to high temperature sterilization treatment such as boiling sterilization, if necessary.

Effect of the invention According to the present invention, the following effects can be obtained.

(i) Sealing takes place at low temperatures and within a short time.

(ii) Since the seal portion has good water resistance, it can be used for a long period of time as a sealed package for containing liquid and fluid substances. Furthermore, uniform sealing is possible regardless of the unevenness of the glass container.

(iii) The bond between the resin and the glass container obtained in the present invention has a high strength that cannot be obtained by short-time thermocompression bonding such as heat sealing, and has excellent water resistance. Moreover, this can be done in the slow cooling process that is part of the glass container manufacturing process.
The cost is also extremely low.

(iv) When filling the contents and heat-sealing with a lid material following the formation of a resin layer on the opening end of the glass container, the heat generated during drying of the resin layer may
The glass container is sterilized at the same time, and as the glass container is heated, the heat-sealing temperature and heat-sealing time are reduced.

(v) Since the seal formed between the glass container and the lid of the present invention has excellent heat resistance, the sealed package can be easily subjected to high temperature sterilization treatment such as boil sterilization.

(vi) When opening a sealed package, breakage occurs at the interface between the resin layer on the glass container side and the resin layer on the lid side, so opening is easy and the appearance of the opening of the glass container is smooth and beautiful.

Example 1 A liquid composition prepared by adding 1% (based on the solid weight of the ionomer) of γ-aminopropyltriethoxysilane to an ionomer emulsion (solid content 30%) containing Na as a cation was poured onto the open end of a glass container. By applying it to the surface and baking it at 180℃ for 30 seconds,
An ionomer layer with a thickness of 5 to 6 μm was formed.

On the other hand, on the other side of the aluminum foil with a thickness of 50 μm, which has a printing layer and an overcoat layer on one side,
A 40 μm low-density polyethylene film, medium-density polyethylene film, or high-density polyethylene film was bonded together via a urethane adhesive to form a lid material.

Next, water was poured into the glass container, a lid material was placed on the top of the glass container so that the ionomer layer and the polyethylene layer were in contact, and the temperature was 200°C x 1 second x 4Kg/cm ²
Heat sealing was performed under the following conditions to obtain a sealed package.

The obtained sealed package was left in an inverted position at room temperature for 6 months, but in all cases no decrease in adhesive strength or any water leakage due to this was observed.

Furthermore, when the obtained package was opened by hand,
In all cases, opening was easy, and the breakage occurred at the interface between both resin layers, so the appearance of the opening of the glass container was smooth, transparent, and beautiful.

Example 2 A glass container was prepared in the same manner as in Example 1.

On the other hand, the thickness with an overcoat layer on the top surface
A urethane anchor coat is applied to the other side of the 50 μm aluminum foil, and 15 μm low density polyethylene (MI 7) is extrusion coated on top of that, and then low density polyethylene (30% by weight)/styrene grafted polyethylene ( A lid material was prepared by extrusion coating a blend resin consisting of 50% by weight)/ethylene-propylene rubber (20% by weight) to a thickness of 20 μm.

Example 1 using the obtained glass container and lid material
A sealed package was prepared in the same manner as in Example 1, and the durability, unsealability, and appearance after opening were evaluated in the same manner as in Example 1, and the results were found to be as good as in Example 1.

Comparative Example 1 A glass container was prepared in the same manner as in Example 1.

The lid material is thick enough to have an overcoat layer on one side.
This was obtained by bonding a 40 μm thick ionomer film to the other side of a 50 μm aluminum foil via a urethane adhesive.

When a sealed package was prepared in the same manner as in Example 1 using the obtained glass container and lid material, it was difficult to open the package because the adhesive strength of the seal portion was too high. Furthermore, when the package was forcibly opened, fragments of the ionomer film remained at the opening of the glass container, giving it an unsightly appearance.

Example 3 An ionomer emulsion (solid content 30%) containing Na as a cation and an emulsion (solid content 40%) mixture (1:1 as solids)
By applying and baking at 230℃ for 20 seconds,
A resin layer with a thickness of 4 μm was formed.

On the other hand, a 40-μm-thick medium-density polyethylene film was bonded to the other side of the 50-μm-thick aluminum foil with an overcoat layer formed on one side via a urethane adhesive to obtain a lid material.

After filling the glass container with sea cucumber tsukudani heated to 60 to 70°C, the lid material was placed on the glass container and heat-sealed at 200°C x 1 second x 4 kg/cm ² . Next, the obtained sealed package is heated to 80 to 90°C.
sterilized by boiling in hot water for 30 minutes.

The adhesiveness and sealability of the sealed portion of the sealed package after cooling were good, the package was easy to open, and the appearance of the opening of the glass container was excellent.

Furthermore, when the sealed package obtained in this example was left in an inverted state for 6 months, no decrease in adhesive strength or deterioration in sealing performance was observed.

Comparative Example 2 A solution prepared by adding 1 part by weight of γ-aminopropyltriethoxysilane to 100 parts by weight of an ionomer emulsion with a solid content of 39% was applied to the heat-sealed surface of the opening of a glass container, and the mixture was heated at 180°C for 30 seconds. It was baked to form a resin layer with a thickness of 10 μm.

On the other hand, a lid material was prepared by laminating a 50-μm-thick aluminum foil with a printing layer and an overcoat layer on one side and a 50-μm-thick ionomer film with a urethane adhesive interposed on the other side.

Next, hot water at 60 to 70°C was poured into the glass container, a lid material was placed on the open end of the glass container so that the ionomer layers were in contact with each other, and at a temperature of 200°C,
A sealed package was heat-sealed by applying a pressure of 3 kg/cm ² for 1 second.

Then, the obtained sealed package was sterilized by boiling at 80 to 90°C for 30 minutes.

After cooling, the sealing portion of the sealed package was partially damaged due to internal pressure stress during boiling, and water leaked.

Furthermore, it was difficult to open this sealed package, and furthermore, ionomer remained at the opening of the glass container after opening, giving it an unsightly appearance.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one example of the glass container according to the present invention, FIG. 2 is a cross-sectional view showing another example of the glass container, and FIG. 3 is a cross-sectional view showing an example of the lid material according to the present invention. It is. 1...Glass container body, 3...Resin layer, 5...
Silane coupling agent layer, 7... base material of lid material,
9...Resin layer of lid material, 11...Printed layer of lid material, 1
3...Overcoat for lid material.

Claims (1)

[Claims] 1. (i) A glass container with a resin layer A formed on the open end surface, and (ii) A resin layer B formed on one side of a base material made of aluminum foil, plastic film, paper, or a laminate of these. A sealing material for a sealed package consisting of a combination of a lid material and a lid material, characterized in that the resin layers A and B are different and are composed of either one of the following (a) and (b). Packaging material: (a) Ionomer alone or a mixed resin of the ionomer and at least one selected from the group consisting of polyolefin, ethylene copolymer, styrene graft copolymer, polyester, acrylic resin, and epoxy resin; ) Polyethylene alone or a mixture of polyethylene and at least one selected from the group consisting of polyolefin (excluding polyethylene of the same type as the polyethylene), ethylene copolymer, styrene graft copolymer, polyester, acrylic resin, and epoxy resin resin. 2. (i) A glass container in which a silane coupling agent layer and a resin layer A are sequentially formed on the open end surface, and (ii) A resin layer B is formed on one side of a base material made of aluminum foil, plastic film, paper, or a laminate of these. A material for a sealed package consisting of a combination with a formed lid material, in which the resin layers A and B are different, and the following (a) and
Materials for sealed packages characterized by being composed of any one of (B): (B) Ionomer alone or ionomer and polyolefin, ethylene copolymer, styrene graft copolymer, polyester, acrylic resin, and epoxy (b) polyethylene alone or polyethylene and polyolefin (excluding polyethylene of the same type as the polyethylene), ethylene copolymer, styrene graft copolymer, polyester, A mixed resin with at least one selected from the group consisting of acrylic resin and epoxy resin.