KR100196812B1 - Improved innerseal for a container and method of applying - Google Patents

Abstract

An easily removable innerseal for a container and method of application relates to an improved arrangement having a body portion (22) adapted for fitting over the upper rim of a container and a flexible element (24) attached to the body portion for a user to grip. The body portion is provided with a lower bonding layer, which includes a first bonding portion (26) and a second bonding portion (28) adhered to the first portion, and a layer (30) to prevent fluid from passing therethrough. The bonding force between the first and second bonding portions is designed to be weaker than the bonding force between the bonding layer and the container. In addition, the rupture strength of the first bonding portion is less than either of the bonding forces. As a result, the force required to remove the innerseal from the container is not dependent upon the amount of heat applied during sealing, because delamination will occur between the two bonding portions in an area over the container rim (14), leaving a residue of the first adhesive portion attached to the rim. By gripping the flexible element and pulling it upwardly, a user can remove the innerseal from the container without having to puncture or scrape the innerseal with a sharp object, which is frequently required to remove innerseals of the type commonly in use today. The method of application includes the steps of applying the body portion of the innerseal around the rim portion of a container and passing the container through an induction type heating station.

Description

[Name of invention]

Inner Seal for Containers

[Background of invention]

[Field of Invention]

The present invention relates to an inner seal of a container which is used in conjunction with a conventional cap having a threaded portion to provide a hermetically sealed closed seal to the container. In particular, the present invention relates to an inner seal that, when attached to a container as compared to an inner seal known to date, not only improves the sealability, ie, the sealing ability of the container, but also facilitates the removal of the inner seal from the container. will be.

[Description of the Prior Art]

A sealing lid developed in view of the industry's need to provide a hermetically sealed closed seal to a container such as food or medicine is to incorporate an inner seal bonded by an adhesive into a rim on top of the container. In order to effect such a sealing, the container filled with contents is capped and then passed through an electromagnetic field generated by an induction heating apparatus to melt the heat sealable polymer film coating by heating the foil layer in the inner seal. One such type of system that has been fully commercially successful is the trade name Safe-Gard, manufactured by 3M Corporation, St. Paul, Minn. Such a system provides a hermetic seal suitable for use in an intake article. Such seals are particularly effective for products that are good at preventing contamination, oxidation and / or moisture. However, it was difficult to effectively control the adhesive force for joining such an inner seal to the container because the sealing force depends on the magnitude of the induced power applied. Therefore, there has been a need to maintain precise control of the amount of power applied during sealing of such containers, and even if the range of the power is effectively controlled, the range of seal tightness has widened. Moreover, the amount of sealing force that can be used is limited by the fact that the end user is proportional to the amount of force required to remove the inner seal from the container. As a result, such a seal had to be drilled or cut with a sharp tool such as a knife. This problem is compounded by the mismatch of sealing force for each container and the limitation of the sealing force described above.

As described in Ullman et al. US Pat. No. 4,754,890, although internal seals with integral tabs formed for gripping purposes have been developed, they are now associated with a limited and unpredictable range of sealing forces. It could not effectively solve the basic problem of grip ability. For this reason, the importance of the present invention can be recognized.

The end user can be easily removed from the container without having to pierce or cut the seal, there is a consistent (constant) removal force that provides a strong seal between the inner seal and the container, regardless of the sealing force, and the need for precise control during the sealing process It is evident that the need for an inner seal for a container capable of eliminating the has remained unsatisfied for a long time in the prior art.

[Summary of invention]

According to the invention, a sealed container of the type provided with a safety inner seal comprises a container body with an upper rim, the inner seal comprising a body portion suitable for covering the upper rim, wherein the body portion allows fluid to pass through the body portion. A membrane structure for preventing and a structure for coupling the body portion to the upper rim of the container, the coupling structure having a first bonding portion coupled to the rim with a first bonding force and a second bonding force; And a second bonding portion adhered to the first coupling portion, wherein the second coupling force is smaller than the first coupling force, and the first coupling portion has a burst strength smaller than any of the first coupling force and the second coupling force. The gripping structure is attached around the outer surface of the body portion so that the seal structure is delaminated internally during removal from the container.

According to a second aspect of the present invention, there is provided a method of forming a sealed container of the type comprising a safety inner seal, the method comprising: providing a container body having an upper rim, and disposing an inner seal of the aforementioned structure on the upper rim; And passing the container and the inner seal through the heating station, wherein the inner seal is sealed to the container body to form a tight and effective seal.

Various advantages and novel features which characterize the invention are also disclosed in the claims, in particular attached later to form part of the invention. However, in order to provide a better understanding of the present invention, the advantages of the present invention, and the objects obtained by using the present invention, reference should be made to the drawings that form part of the present invention and the accompanying detailed description. In the following, preferred embodiments of the present invention are illustrated and described.

[Brief Description of Drawings]

1 is a perspective view of a sealed container constructed according to the first embodiment of the present invention.

2 is a partial cross-sectional view of the inner seal of the container shown in FIG. 1,

3 is a cross-sectional side view of an inner seal constructed in accordance with a second embodiment of the present invention,

4 is a cross-sectional view of the inner seal shown in FIG.

5 is a cross-sectional view of the container of FIG. 1 showing the process of removing the inner seal from the container,

6 is a graph showing the relationship between the sealing force versus the opening force between the known sealing structure and the present invention,

7 is a perspective view of a work station for attaching and sealing an inner seal according to the invention.

Detailed description of the invention

Throughout the drawings, the same reference numerals indicate corresponding structures.

Referring to FIG. 1, in a container 10 having a neck 12 and a rim 14, a raised helical screw 16 is formed on the surface of the neck 12. As is well known in the neck portion may be covered with a suitable sealing cap (lid) with a screw coupled with the screw 16.

A sealing structure 18 is provided for engaging the aperture formed in the container 10 by the rim 14. The sealing structure 18 includes a removable inner seal 20 having a circular body portion 22 and a flexible tab portion 24, as shown in FIG. The main body portion 22 is sized to span the entire region of the container hole and the rim 14. The tab portion 24 shown as an example of the gripping means is connected to the outer periphery (edge) of the body portion 22, as shown in FIG. 1, in the preferred embodiment the same as the body portion 22, In addition, a layer extending from the main body portion is formed of a layered material.

In all the embodiments below, the sealing layer or the bonding layer commonly includes a first bonding portion and a second bonding portion. The first coupling portion is attached to the rim 14 of the container with the first coupling force, and is attached to the second coupling portion with a second coupling force smaller than the first coupling force. The first coupling portion has a burst strength smaller than either of the first coupling force or the second coupling force. The sealing layer is bonded to the rest of the body portion with a third bonding force greater than the second bonding force.

2 is a partial cross-sectional view of the layers that gather together to form the inner seal 20. A first joining portion, such as a sealing layer 26 made of a sealable material by heating, is provided on the bottom surface of the inner seal 20 and joined to the upper rim 14 of the container 10. In a preferred embodiment, the sealing layer 26 is formed of a multilayer polymer film such as polyethylene or polyester and has a thickness of 0.5-4 mils (0.0127-0,102 mm). Most preferred sealing layer 26 is approximately 1 mil (0.0254 mm) thick. Alternatively, the sealing layer 26 may be formed of polypropylene, ethylene vinyl acetate copolymer (EVA) or similar heat sealable materials having relatively low tensile and shear strengths. On the top surface of the sealing layer 26 a second bond, such as a layer 28 of pressure sensitive adhesive, ie a pressure sensitive adhesive (PSA), is laminated. For example, layer 28 may be formed of Adcote 503 A, available from Morton Norwich Products, Inc., Chicago, Illinois.

Sealing layer 26 is bonded to layer 30 of fluid impermeable material by layer 28 of adhesive. In a preferred embodiment, the layer 30 is formed of metallic foil. It is also most desirable to form the layer 30 from aluminum foil having a thickness of between 1-2 mils (0.0254-0.051 mm).

The reinforcement layer, ie the reinforcement layer 34, is laminated to the layer 30 by a layer 32 of laminated adhesive, which may be formed, for example, of Adcote 503 A. In a preferred embodiment the reinforcement layer 34 is formed by polyester with a thickness between 0.5-20 mils (0.0127-0.508 mm). Preferably, the thickness is between 2-4 mils (0.051-0.101 mm). Alternatively, the reinforcement layer 34 may be formed of paper, polyethylene, a polymer foam (foam) type sheet material, or an equivalent material having a relatively high strength against tearing. An example of a paper suitable as the reinforcing layer 34 is 80 1b. Bleached kraft paper from Sorg Paper Co., Middleton, Ohio. The weight of this paper is 80 lbs per rim, ie 130 g / m ² . As a second alternative, the reinforcement layer 34 is a registered trade name Tyvek manufactured by DuPont. It can be made from a class of materials known as nonwoven fabrics, such as. In a preferred embodiment, the various layers of the inner seal described above with reference to FIG. 2 extend through both the body portion 22 and the tab portion 24 of the inner seal 20.

Two configurations of the inner seal which proved to be a structure according to the embodiment of FIG. 2 and are actually satisfactory are described below.

Example 1

In a configuration suitable for use in a container 10 formed of polyester or polyvinyl chloride, the sealing layer 26 is formed from a 50 OL-2 Mylar brand film, which is a top layer of 0.4 mils (0.01 mm) thick. And a lower layer bonded to the upper layer with a thickness of 0.1 mils (0.002 mm). The top and bottom layers are both made of polyester, and the bottom layer is formed to have a lower melting point than the top layer for sealability (sealing ability). In this configuration, the adhesive layer 28 is formed of an Adcote 503A adhesive, and the layer 30 is formed of an aluminum foil having a thickness of approximately 1 mil (0.025 mm). Reinforcing layer 34 is an adhesive layer (having a thickness of approximately 32 is formed into a polyacrylic ester film 2mils (0.05mm) formed of Adcote 503A adhesive spread to a coating weight (77.4-117.2mg / 200cm ²⁾ of from 0.925 to 1.4 grains per 24inch ² Is bonded to the layer 30. In this configuration, it was found that a layer delimination occurs in the sealing layer 26 when the inner seal is removed from the container.

Example 2

In this configuration, the sealing layer 26 is formed of Mylar 50-OL2 film having a total thickness of approximately 0.5 mils (0.0127 mm) and formed by the method described with respect to Example 1. Layer 30 is formed of aluminum foil approximately 1 mil (0.025 mm) thick and bonded to layer 26 by layer 28 formed of Adcote 503A adhesive. Reinforcing layer 34 is formed by a polyethylene foam having a thickness of about 5mil (0.127mm), this is an adhesive layer as Adcote 503A adhesive spread to a coating weight (77.4-117.2mg / 200cm ²⁾ of from 0.925 to 1.4 grains per 24inch ² ( 32 to the layer 30. Also in this structure, it discovered that layer peeling generate | occur | produced in the sealing layer 26, while opening an inner seal.

3 is a partial cross-sectional view of a second embodiment of an inner seal 48 constructed in accordance with the present invention. The inner seal 48 includes a first bond portion embodied as a sealing layer 26, a fluid impermeable layer 30, an adhesive layer 32 and a reinforcing layer 34, each of which is shown in FIG. Corresponding to each layer described above with respect to the embodiment. However, the inner seal 48 includes a second bonding portion embodied as an adhesive layer 52 and an adhesive primer layer 50, which together layer the foil layer 30 to the sealing layer 26. To be bonded. Adhesive layer 52, for example, the coating weight of approximately 1-2 grains per 24inch ² (83.7-167.4mg / 200cm ²⁾ is preferred trademark Creighton (Kraton spreading 1107 adhesive. The primer layer 50 is provided to adhere the fluid impermeable layer 30 more strongly than the adhesion layer 52 to the sealing layer 26. By doing so, the inner seal 48 is constrained to delaminate along the interface between the adhesive layer 52 and the sealing layer 26 when removed from the container 10. The primer layer 50 is preferably formed of a chlorinated polyolefin such as CP343-1 primer manufactured by Eastman Chemical Corporation, Kingsport, Tenn.

The following describes examples of two inner seals 48 that have been manufactured and proven satisfactory.

Example 3

In this configuration, the sealing layer 26 was formed of a polyethylene film having a thickness of approximately 1 mil (0.025 mm). Adhesive layer 52 is registered trademark Creton It was formed with 1107 adhesive and spread to approximately 1 grain coating weight (83.7 mg / 200 cm ² ). The primer layer 50 was formed of Eastman's CP 343-1 primer. Layer 30 is formed of aluminum foil, 24inch an adhesive layer 32 as Adcote 503A adhesive spread to a coating weight (77.4-117.2mg / 200cm ²⁾ of from 0.925 to 1.4 per grain ² having a thickness of about 1mil (0.025mm) To layer 34 by means of The reinforcement layer 34 was formed of a polyester film having a thickness of approximately 2 mils (0.05 mm).

Example 4

In this configuration, the sealing layer 26 was formed from a polyethylene film having a thickness of approximately 1 mil (0.025 mm), and the sealing layer 26 was spread out at approximately 1 grain of coating weight (83.7 mg / 200 cm ² ). Creton The adhesive layer 52 formed of 1107 and the primer layer 50 formed of Eastman's CP 343-1 primer were bonded to a layer 30 made of aluminum foil having a thickness of approximately 1 mil (0.025 mm). The reinforcement layer 34 was formed of a sheet of kraft paper of 80 1b./rim (130 g / m ² ) having a thickness of approximately 6 mils (0.152 mm), and the reinforcement layer 34 was formed in Example 1 Spread to the coating weight described above and bonded to layer 30 by an adhesive coating of Adcote 503A.

4 and 5, the removal of the inner seals 20, 48 from the container 10 will be described. The inner seal 20 is sealed to the rim 14 of the container 10 in the manner described below. As shown in FIG. 4, the tab portion 24 is grasped and pulled upward to remove the inner seals 20 and 48 from the position around the rim. Since the adhesive layer is bonded to the sealing layer with a bonding force less than the bonding force between the sealing layer and the container rim, this operation initially seals the adhesive layer 52 of the portion of the inner seal 20 covered over the rim 14. The layer is peeled off from (26). In FIG. 5, this peeled portion is shown as the strip surface 38. At this time, the portion of the sealing material, ie, the peeling layer 36, remains adhered to the rim 14. Since the tear strength of the sealing layer 26 is less than the above-mentioned coupling forces, if the tab portion 24 is pulled further upward, the sealing layer 26 is ruptured and then the body portion 22 is completely removed from the container 10. It is gradually torn along the inner edge of the rim 14 until it is removed. The release layer 36 of the sealing material remains adhered to the rim 14 and does not prevent the removal of the sealing material from the container 10.

In the case of the inner seal 20, layer peeling occurs in the sealing layer 26 when the tab portion 24 is caught and pulled up. When forming the sealing layer 26 using a 50 OL-2 Mylar brand film, the layer is peeled along the interface between two layers of polyester in the film, except that a predetermined amount is separated into the lower layer during layer peeling. Was found to occur. For example, layer peeling occurs initially at the interface, slightly off to the lower layer of polyester, and then back to the interface layer. The stripped area to adhere to the rim 14 is shown in FIG. 5 as the strip surface 38. In the case of the inner seal 48, the release layer 36, which is part of the seal material, remains adhered to the rim 14. As the tab portion 24 is pulled upwards, the sealing layer 26 ruptures and then gradually tears around the inner edge of the rim 14 until the body portion 22 is completely removed from the container 10. All.

Since the layer peeling does not occur directly between the sealing layer 26 and the rim 14, but occurs inside the inner seals 20, 48, during the sealing process as in the case of the known inner seal structure. It is not necessary to maintain precisely the amount of heat that must be applied to the sealing layer 26.

FIG. 6 is a graph showing the advantages of the present invention over the construction of the prior art, where curve 54 is a trademark Vitel for power set in an induction heating station used to melt an adhesive layer in a container. It exhibits the force required to open a conventional inner seal with a single amorphous polyester adhesive layer such as PE 100. Trademark Vitel PE 100 is available from Goodyear Tire & Rubber Company in Akron, Ohio. Curve 56 represents the force required to open the inner seal made according to Example 1, which was described with respect to the inner seal 20.

In experiments on the opening force used to generate the data shown in FIG. 6, a 4 oz. (118.3 ml) 43.410 finish threaded polyester bottle was used with a 43410 finish polypropylene cap. Bottles were used by Setco Inc., Anaheim, CA, and caps were used by Tubed Products Inc., Istamton, Maine. Each inner seal tested was folded into the cap with the tab folded between the cap and the inner seal and the heat sealable side of the inner seal facing the open end of the cap. The cap was tightened to 20 inches-pounds (230.59-m) by a spring torque tester from Owens Illinois Grass, Toledo, Ohio. The inner seal was bound to the bottle with a Lepel high frequency induction device (Model NO. T-2.5-1KC-AP-BW) from Repel High Frequency Laboratories, New York, NY. The power setting of the induction device was variable and is indicated as a percentage in FIG. 6 to determine the effect on the opening (removal) force.

After joining the inner seal, the bottle, cap and inner seal were cooled and the cans removed. Fold NO.898 filament tape, commercially available from 3M, St. Paul, Minn., In half, with the adhesive side contacting each other, and bonding the adhesive side to the opposite side of the tab of the inner seal, respectively. I was. The bottle was then clamped to the lower jaw of an Instron Model 1123 tensile tester so that the bottle was vertical. Filament tape was clamped to the upper jaw of the Instron tester. As each jaw of the Instron was removed, the inner seal was removed from the bottle and the level of force reached at the time of separation was recorded.

Comparing curves 54 and 56, it is clear that in order to keep the opening force within the desired range, the present invention can use a much larger range of power settings than would have been possible for the inner seal of the prior art. Can be. Therefore, it is possible to maintain a higher level of quality control with respect to the opening force of the container sealed with the inner seal according to the present invention.

Referring to FIG. 7, a preferred process for attaching the inner seals 20 and 48 to a container is described below. As shown in FIG. 7, first, the inner seals 20 and 48 are disposed in the openings (holes) in the container 10 so that their circumferential edges cover the rim 14. This may be done directly, or the cap member may be arranged such that the inner seal 20, 48 is pressed against the rim 14 after arranging the inner seal 20, 48 in the threaded cap member in a known manner. You may screw to the screw 16 of the neck 12. This process at the attachment station 40 is schematically illustrated in FIG. After attaching the inner seals 20, 48 to the vessel 10, the assembly is transferred to a heat seal station 42 including an induction heater 44 by a conveyor 46 or the like. The assembly of the bottle 10 and the inner seal 20 heats the layer 30 of metallic foil as it passes through the induction heater 44, which in turn adheres the layer 26 to the rim 14. And effectively seal the inner seal 20 to the neck 12 of the container 10. The amount of heat applied to the inner seal 20 is greater than the force present between the layer 26 and the pressure sensitive adhesive layer 52 for the reasons described above and to ensure proper sealing of the container 10. Should be sufficient to melt and bond to the rim 14.

Although various features and advantages of the present invention have been described above along with the detailed aspects of the functions and structures of the present invention, these are only examples, and sufficient scope is indicated by the broad general meaning of the terms expressed in the appended claims. It should be understood that various changes can be made in the aspects of the shape, size, and arrangement of the respective parts within the spirit of the present invention.

Claims (4)

An inner seal for use in a vessel with a hole formed by an upper rim, the inner seal having a body portion with an upper surface overlaid on the upper run of the vessel, the body portion being capable of (i) allowing fluid to pass through the body portion. A layer of fluid impermeable material to prevent, (b) a bonding layer for coupling the body portion to the upper rim of the container, the first coupling portion coupled to the upper rim with a first coupling force, and one side of the fluid impermeability A bonding layer bonded to the layer of permeable material and opposite the face having a second coupling portion coupled to the first coupling portion with a second coupling force less than the first coupling force, and (c) removing the inner seal from the container. A gripping means attached to an outer circumferential edge of the body portion for removal by the user during removal, wherein the bonding layer is smaller than any of the first and second bonding forces. Those made of a material having a heat seal strength of the inner as claimed. The method of claim 1, wherein the first bonding portion comprises a heat sealable film layer consisting mainly of a material consisting of polyester, polypropylene, polyethylene, ethylene vinyl acetate copolymer and also laminates or brands thereof, And the second bonding portion comprises a pressure sensitive adhesive layer. 2. The inner seal as claimed in claim 1, wherein said graphing means and said body portion are formed of a conventional layer material extending continuously. The container body of claim 1, wherein the upper body has a top rim that defines a hole. The inner seal is coupled to the upper rim with the first coupling force.