JP4765299B2 - Inner seal material for high frequency seal - Google Patents

Description

  The present invention relates to an inner seal material that seals an opening of a container made of glass or the like that contains, for example, powdered and granular contents such as instant coffee and instant powder, and particularly performs high-frequency sealing. It relates to an inner seal material.

Generally, an inner seal material is used to protect the contents from quality deterioration due to moisture, oxidation, etc., in the container mouth portion for containing powdered and granular contents such as instant coffee, instant powder and seasonings. Yes.
This inner seal material consists of a laminate of reseal parts mainly made of elastic mount such as paperboard using virgin pulp and foamed plastic, and membrane parts mainly made of metal foil such as aluminum foil. When the cap is removed, the reseal part and the membrane part are separated from each other, the reseal part remains inside the cap, the membrane part remains at the container mouth, and the cap is again placed at the container mouth. When the cap is attached, the reseal portion is layered on the membrane portion, and plays a role of preventing re-entry of moisture, oxygen and the like into the container together with the cap.

  Conventionally, thin film was provided in the middle layer of the membrane for the adhesion of the membrane part to the container mouth, and emulsion adhesive or starch glue was used. Because there are problems such as paper smearing and difficult to remove cleanly, it is a thin film for sealing that can be easily and quickly adhered to the container mouth to improve this. A high frequency sealing method has been developed as a method for sealing the container mouth.

  This high frequency seal heats the metal layer itself by placing the metal layer contained in the inner seal material in a magnetic field, and seals using this heat.

  However, the membrane part of the conventional high-frequency seal type inner seal material is bonded to the inner surface of an aluminum foil with a thickness of 10 μm or more, extruded with a thermoplastic resin or hot melt agent, or coated. Are made.

  For this reason, since the whole aluminum foil is naturally heated at the time of high frequency sealing, the center part of the membrane part which does not participate in sealing will also be heated. The high frequency seal only needs to be able to heat only the peripheral edge of the membrane part in contact with the container mouth. Especially in the case of a combination of a container with poor adhesion and a membrane part, it is necessary to lengthen the oscillation time to raise the temperature of the adhesion surface or to increase the output. The temperature will rise.

  The problems of the temperature rise in the central part not related to the high-frequency seal are as follows: • Low sealant low molecular weight and easily volatile components due to temperature rise;・ Normally, the heat tends to be transferred from the peripheral part of the membrane to the central part during high frequency oscillation due to heat conduction, so the heat of the peripheral part necessary for sealing is taken away by the central part, resulting in poor energy efficiency. The point is mentioned.

The present invention has been made in view of the above-described problems related to the inner seal material that performs high-frequency sealing, and prevents the energy loss due to heat conduction and is a sealant material that may cause a strange odor to the contents due to heat generation at the center. It is an object of the present invention to provide an inner seal material for high-frequency sealing that suppresses generation of low molecular weight components and the like.

The invention of claim 1 of the present invention comprises a membrane part having at least a sealant layer and a reseal part having at least an elastic sheet layer, wherein the membrane part and the reseal part can be peeled , and the membrane part is a container and lowermost sealant layer in contact with the mouth portion, the inner seal member ing from a membrane substrate located thereon, the membrane substrate is a paper substrate, the side in contact with the sealant layer of the membrane substrate The conductive aluminum fine powder having a size of 5 × 10 ⁻² μm to 1 × 10 ² μm and an addition amount in the range of 20 to 90%, and a binder resin so as to overlap the periphery of the container An inner seal material for high-frequency seals , characterized in that a metal paste layer composed mainly of is printed on.

The invention of claim 2 of the present invention comprises a membrane part having at least a sealant layer and a reseal part having at least an elastic sheet layer, wherein the membrane part and the reseal part can be peeled, and the membrane part is a container In the inner seal material consisting of the lowermost sealant layer in contact with the mouth part and the membrane base material located on the lower sealant layer, the membrane base material has a piercing property that can be pierced with a finger or the like, and the sealant layer at a high frequency. A paper base material on which a metal paste layer for heat sealing can be printed, and a size of 5 × 10 ^{− in} the periphery of the membrane base material in contact with the sealant layer so as to overlap the container mouth Gold composed of ² μm to 1 × 10 ² μm , conductive aluminum fine powder in the range of 20 to 90% and binder resin as main materials An inner seal material for high-frequency seals , wherein a metal paste layer is applied by printing .

  As described above, according to the first and second aspects of the present invention, the membrane part is composed of the lowermost sealant layer in contact with the container mouth part and the membrane base material positioned thereon, and the membrane base material. Since the metal paste layer is applied to the peripheral edge of the side in contact with the sealant layer so as to overlap the container mouth part, the inner seal material is placed on the container mouth part so that the sealant layer is in contact with the container mouth part. When high frequency sealing is performed, the inner seal material is tightly sealed to the container mouth.

According to the invention of claim 1, wherein the metal paste layer is composed of a conductive aluminum fine powder and a binder resin as a main material, the size of the conductive fine aluminum powder is 5 × 10 ^-2 [mu] m to Since it is in the range of 1 × 10 ² μm, it is easy to produce and obtain a fine powder, the coating property is good, and the inner seal material can be produced relatively easily.

Moreover, according to invention of Claim 1, 2 of this invention, since the addition amount of the metal fine powder which comprises a metal paste layer is the range of 20-90%, when a high frequency is transmitted, it heats moderately, Liquefaction and paste can be made easily.

According to the invention of claim 1, wherein the present invention, as the conductive metal fine powder before Symbol metal paste layer, the use of the aluminum fine powder, there is a cost, hygiene benefits.

  As described above, according to the present invention, it is possible to provide an inner seal material with less off-flavor and less energy loss.

The present invention will be described in detail below based on one embodiment.
The inner seal material (1) of the present invention includes, for example, as shown in FIG. 1, a membrane portion (10) having at least a sealant layer (11), and a reseal portion (20) having at least an elastic sheet layer (21). Consists of.

  More specifically, for example, the membrane part (10) comprises a lowermost sealant layer (11) in contact with the container mouth part (2) and a membrane base material (12) located thereon, A metal paste layer (13) is coated on the periphery of the base (12) on the side in contact with the sealant layer (11) so as to overlap the container mouth (2).

  The reseal portion (20) has a configuration in which an adhesive layer (22) and a release layer (23) are sequentially provided below the uppermost elastic sheet layer (21).

  With such a configuration, the inner seal material (1) of the present invention can peel the membrane part (10) and the reseal part (20) between the membrane substrate (12) and the release layer (23). Is formed.

  The sealant material for forming the sealant layer (11) must be capable of high-frequency sealing with the container mouth (2), and polyethylene, polypropylene, ethylene / vinyl acetate copolymer, wax, etc. are used alone or in combination. A combination of the above can be preferably used. Furthermore, for the purpose of improving adhesiveness, a tackifier such as rosin or terpene may be added to the above substance.

Since the membrane substrate (12) remains in the mouth of the container as a membrane, it must be pierced with a finger or the like, so that the piercing strength is weak and a metal powder paste such as an aluminum paste can be printed. It will be necessary.
For example, high-quality paper or bleached kraft paper can be preferably used to satisfy such conditions. The basis weight is preferably up to about 100 g / m ² due to the problem of piercing. Moreover, in order to improve coatability with an aluminum paste etc., you may apply | coat a sealing agent like a clay coat to the paper surface.

  The metal paste layer (13) is applied by printing a metal paste obtained by mixing conductive metal fine powder and a binder resin on the periphery of the membrane substrate (12) so as to overlap the container mouth. Examples of the conductive metal include silver, aluminum, and copper. Aluminum is desirable from the viewpoint of cost and hygiene, but other metals may be used depending on the required quality.

The size of the conductive metal fine powder is preferably in the range of 5 × 10 ⁻² μm to 1 × 10 ² μm. If the size is less than 5 × 10 ⁻² μm, the production of fine powder becomes extremely difficult and the cost increases. On the other hand, when the size is 1 × 10 ² μm or more, the coating property is deteriorated and the production is impossible.

  The metal addition amount is preferably about 20% to 90%. If it is less than 20%, it does not heat even if high frequency is oscillated, and if it is 90% or more, it is difficult to liquefy and paste and it cannot be applied to the membrane substrate.

  Although it does not specifically limit as binder resin, For example, acrylic resin, nitrified cotton resin, urethane resin, alkyd resin, urea resin, phenol resin, etc. can be used preferably. In order to improve the dispersibility of the metal fine powder, a dispersant and other additives may be added.

The elastic sheet layer (21) constituting the reseal portion (20) becomes a packing when the consumer re-seals after opening the inner seal material, and an elastic mount or foam can be preferably used.
The board is preferably a paperboard having a thickness of 0.3 mm or more using 100% virgin pulp. As the foam, a foamed sheet of a thermoplastic resin such as polyethylene, polypropylene or urethane can be used. At the time of use, each may be used alone or in combination of two or more. Moreover, you may stick a film (not shown) to the interface with the contact bonding layer (22) mentioned later.

  The adhesive layer (22) is not limited as long as it adheres a release layer (23) and an elastic sheet layer (21), which will be described later, but it can be used as an extruder laminate using wax, polyethylene, polypropylene, or the like. It is formed on the elastic sheet layer (21) by a technique such as dry lamination or wet lamination.

  The release layer (23) is not particularly limited as long as the strength is controlled so that the membrane part (10) and the reseal part (20) can be easily peeled when the consumer first opens the cap. As a method often used, there are methods using “point coating of peeling varnish + adhesive varnish” and “weakly controlled anchor coating agent”.

FIG. 2 is an explanatory cross-sectional view showing a state in which the inner seal material thus produced is mounted inside the cap and the cap is attached to the container mouth. In the figure, (3) is a cap, (4) is a container body, (5) is a rib projecting on the inner side of the cap, (6) is a thread on the outer surface of the container mouth, and (7) is the cap side. This is the thread on the inside of the part.
When the cap (3) is attached to the container mouth, the inner sealing material (1) inside the cap (3) is brought into contact with the tip of the container mouth by the elasticity of the elastic sheet layer (21), and a magnetic field by the high frequency induction heating method. By letting it pass through, the tip of the container mouth and the sealant layer (11) of the inner seal material (1) are completely bonded.

  Next, when the cap (3) is removed, as shown in FIG. 3, peeling occurs between the peeling layer (23) and the membrane substrate (12), and the reseal portion (20) is built in the cap (3). The membrane part (10) remains in the container mouth part (2).

  Hereinafter, the present invention will be described in detail by way of examples.

Prepare high-quality paper with a basis weight of 60 g / m ² as the membrane substrate (12), and in the order of sealing varnish (all solid), release varnish (all solid), and heat seal varnish (point) on the outer surface of this fine paper Printing was performed by a printing method to form a release layer (23).

Further, an aluminum paste was applied on the back surface so as to have a thickness after drying of 25 μm in accordance with the size of the container mouth portion (2) to form an aluminum paste layer as a metal paste layer (13).
The aluminum fine powder in the aluminum paste had a size of 1 μm to 3 μm, an aluminum content of 60%, 20% acrylic resin, and the remaining 20% solvent component.

  Further, on the side of the membrane substrate (12) on which the metal paste layer (13) is formed, a hot melt resin in which a rosin tackifier is added to an ethylene / vinyl acetate copolymer is applied to a thickness of 30 μm. A layer (11) was formed to produce a membrane part (10).

A stretched polyethylene as an adhesive layer (22) is bonded to the release layer (23) side of the membrane part (10) by sand-poly processing, and a basis weight of 600 g as an elastic sheet layer (21) is further formed thereon by a wax lamination method. A re-sealed part (20) was formed on the membrane part (10) by laminating with a board made of 100% virgin pulp of / m ² .

  Finally, it was punched into a circle having a diameter of 51 mm to obtain an inner seal material (1) of Example 1.

  Layer structure of [outer side] polypropylene resin base layer (thickness 20 μm) / polyethylene resin (thickness 10 μm) 20% ethylene / vinyl acetate copolymer [inner side] as sealant layer (11) in contact with the container mouth The same material and method as in Example 1 were used except that an easy peel material having a thickness of 30 μm was bonded to fine paper as a membrane substrate (12) coated with a metal paste layer on the periphery by a dry laminating method. Thus, the inner seal material (1) of Example 2 was obtained.

As a comparative example, an aluminum foil having a thickness of 20 μm was prepared as a membrane substrate, and a release layer was formed on the outer surface using the same material and method as in Example 1. Further, a hot melt resin as a sealant layer was applied to the inner surface using the same material and method as in Example 1 to produce a membrane part.
Next, a reseal part was produced on the release layer side of the membrane part using the same material and method as in Example 1. Finally, in the same manner as in Example 1, it was punched into a circle having a diameter of 51 mm to obtain an inner seal material of Example 3.

Similarly, as a comparative example, a release layer was formed on the outer surface of a high-quality paper having a basis weight of 60 g / m ² , which is a membrane substrate, using the same material and method as in Example 1. On the back surface, the aluminum paste used in Example 1 was applied to a total thickness of 25 μm to form an aluminum paste layer. On top of that, the easy peel material used in Example 2 was bonded together by a dry laminating method, a sealant layer was formed, and a membrane part was produced. Subsequent steps were performed in the same manner as in Example 1, and the inner seal material of Example 4 was obtained.

The inner seal material of Examples 1 to 4 thus produced was set on a cap, tightened with a tightening torque of 294 N · m, heated at a high frequency of 45 KHz for 1.0 seconds and 1.5 seconds, and the following: Evaluation was performed. The results are shown in Table 1.
・ Sealing property: Opened by hand and visually confirmed that there are no unbonded parts. ・ Puncture strength: Measures the strength when the seal surface peels off by sending air into the container.
Fixed / Odor… Welded using an empty bottle, opened immediately and the odor in the bottle is sensually
Evaluated (ranked), from the best, ◎ → ○ → △ → ×
・ Finger piercing property… Seal and seal only the membrane part, and a hole can be easily drilled with a finger.
Sensory test and puncture strength… The puncture strength is measured numerically with a needle with a tip of φ1, R0.5

表１の結果からわかるように、実施例１と実施例２のインナーシール材では、発振時間が短くても接着性、臭気とも問題がなく、比較例である実施例３、実施例４のインナーシール材では、発振時間を増やすと接着性はよくなるが臭気に影響が出ることが判る。

As can be seen from the results in Table 1, the inner seal materials of Example 1 and Example 2 have no problem in adhesion and odor even when the oscillation time is short, and the inner seals of Examples 3 and 4 are comparative examples. It can be seen that when the oscillation time is increased, the sealing material improves the adhesion but affects the odor.

One Example of the inner-seal material of this invention is shown, (a) is sectional explanatory drawing, (b) is plane explanatory drawing. It is a section explanatory view showing the state where the inner seal material concerning one example of the present invention was loaded in the cap, and this cap was crowned on the container mouth. FIG. 3 is an explanatory cross-sectional view showing a state in which when the cap is removed from the container body from the state shown in FIG. 2, the reseal part remains in the cap and the membrane part remains in the container mouth part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inner seal material 2 ... Container mouth part 3 ... Cap 4 ... Container body 5 ... Rib projected inside cap side part 6 ... Thread on outer side of container mouth part 7 ... Cap side part Inner thread 10 ··· Membrane portion 11 ··· Sealant layer 12 ··· Membrane substrate 13 · · · Metal paste layer 20 · · · Reseal portion 21 · · · Elastic sheet layer 22 · · · Adhesive layer 23 · · · Release layer

Claims (2)

It comprises a membrane part having at least a sealant layer and a reseal part having at least an elastic sheet layer, and the membrane part and the reseal part are detachable , and the membrane part is a lowermost sealant layer in contact with a container mouth part. in the inner seal member ing from a membrane substrate located thereon, the membrane substrate is a paper substrate, the periphery of the side in contact with the sealant layer of the membrane substrate, overlaps the container mouth portion As described above, a metal paste layer composed mainly of conductive aluminum fine powder having a size of 5 × 10 ⁻² μm to 1 × 10 ² μm and an addition amount of 20 to 90% and a binder resin. An inner seal material for high-frequency seals , characterized in that is coated by printing . It comprises a membrane part having at least a sealant layer and a reseal part having at least an elastic sheet layer, and the membrane part and the reseal part are detachable, and the membrane part is a lowermost sealant layer in contact with a container mouth part. In the inner seal material consisting of the membrane base material located above, the membrane base material has a piercing property that can be pierced with a finger and the like, and a metal paste layer is printed for heat-sealing the sealant layer at a high frequency. A possible paper base material, the size of which is 5 × 10 ⁻² μm to 1 × 10 ² μm added to the periphery of the membrane base material in contact with the sealant layer so as to overlap the container mouth A metal paste layer composed mainly of conductive aluminum fine powder in an amount of 20 to 90% and binder resin is printed and applied. RF sealing inner sealing element, characterized in that is.

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