JPH0329664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to an easy-to-open heat-sealed lid, and more particularly to a heat-sealed lid that has improved opening performance, drop impact resistance, and easy tab attachment. The present invention relates to an easy-to-open heat-sealed lid with a novel tab attachment structure.

(Prior Art) The present inventors have previously developed an easy-to-open heat-sealable lid for sealing the container body by forming a heat-sealing portion with the container body, the lid having at least an inner surface layered with a heat-sealable resin layer. A score for dividing the part to be opened is provided inside the part of the lid to be heat-sealed in a suitable manner in the middle of the thickness direction of the lid, and a score for opening is provided on the outer surface side of the lid and within the score division part. We proposed a container lid made by gluing a tab. Although this container lid is easy to open and has a high degree of sealing reliability, there are still problems to be solved in terms of attachment of the opening tab and opening performance.

(Problem to be Solved by the Invention) That is, in this heat seal lid, the tearing tip of the opening tab is pushed into the opening start part of the score to form a cut in the score, and then the opening tab is pulled. This requires a two-step motion in which the opening tab is pulled from the beginning and the opening tab is pulled from the beginning, or the opening tab may peel off from the lid. Easy to occur. Furthermore, although the heat-seal lid body is made of a relatively thin flexible material, the opening tab must be made of a material with some degree of rigidity in order to open the lid by pushing as described above. First, because the two materials are poorly matched, there are drawbacks such as a decrease in mechanical properties such as impact resistance of the portion where the opening is to be made, difficulty in installation, and poor appearance.

It is therefore an object of the present invention to provide improved aperture performance;
An object of the present invention is to provide an easily openable heat-sealed lid having a novel tab attachment structure that is resistant to drop impact and allows for easy tab attachment operations.

Another object of the present invention is to provide an easy-to-open heat-sealed lid that can be opened by tearing the score with a single operation of pulling the opening tab.

Still another object of the present invention is to provide an easy-to-open heat-sealed lid in which the opening tab is firmly held without coming off from the lid material, and opening can be easily initiated by cutting the score. It is in.

Still another object of the present invention is to provide an easy-to-open heat-sealed lid that is suitably used for covering and sealing plastic containers or laminated containers made of aluminum foil, paper, and/or plastic.

(Means for Solving the Problems) According to the present invention, there is provided an easy-open heat-sealable lid for sealing the container body by forming a heat-sealing portion with the container body, and the lid is heat-sealed at least on the inner surface side. It is a flexible lid made of a flexible resin layer, and a score defining a portion to be opened is provided inside the portion of the lid to be heat-sealed so as to reach halfway in the thickness direction of the lid, and the outer surface of the lid is Adhere a flexible opening tab to the side and within the score compartment, near the opening start of the score compartment and on the inside surface of the lid, such that one end thereof is located at the opening start of the score. A backing material that is more rigid than the opening tab and is made of the same type of resin as the heat-sealable resin layer is adhered, and the opening tab adhesive part and the backing material are each adhered in a sandwich pattern with the lid material in between. An easy-to-open heat-sealable lid is provided.

The present invention also provides an easy-to-open heat-sealable lid for sealing the container body by forming a heat-sealing portion with the container body, the lid being a flexible lid having at least an inner surface made of a heat-sealable resin layer. and
A score defining a portion to be opened is provided inside the portion of the lid to be heat-sealed so as to reach halfway in the thickness direction of the lid, and a small portion passing through the lid is provided near the opening start portion of the score portion. A backing made of the same type of resin as the heat-sealable resin layer is provided with a hole, on the inner surface of the lid and within the score compartment, one end of which is located at the beginning of the opening of the score and completely closes the small hole. The adhesive material is adhered, and a flexible opening tab is adhered to the outer surface of the lid and in close contact with the lining material inside the small hole, making the lining material more rigid than the opening tab. An easy-to-open heat seal lid is provided.

(Function) In the easy-to-open heat-sealable lid of the present invention, a lid material whose at least the inner surface is made of a heat-sealable resin layer is used, and a portion of the lid to be opened is defined inside the portion of the lid that is to be heat-sealed. The score is provided so as to reach halfway in the thickness direction of the lid, but the opening tab provided on the outer surface of the lid and within the score compartment is a flexible opening tab, and is used in combination with this opening tab. A feature is that the backing material is rigid and made of the same type of resin as the heat-sealable resin layer.

That is, in the present invention, a flexible material similar to the lid material or a flexible material rather than the lid material can be used as the opening tab, thereby matching the characteristics of the lid material and the tab. , an easy-to-open heat-sealed lid with good drop impact resistance and good appearance characteristics can be obtained.

The problem with using a flexible tab as the opening tab is that since both the tab and the lid are flexible, there is no fixed point of force for opening, making opening difficult. In the present invention, the backing material provided near the opening start part of the score section and on the inner surface side of the lid is made of the same type of resin as the heat-sealable resin layer of the lid material. By making this backing material more rigid than the opening tab, even if both the tab and the lid are flexible, the point of action can be increased. Fixed near the opening start part,
The opening operation can be performed smoothly.

In the lid of the first aspect of the present invention, since the lid material is not provided with any openings such as holes, the lid has the advantage of being a heat-sealed lid with particularly excellent sealing performance (sealing reliability). It is.

In the lid of the second aspect of the present invention, a small hole passing through the lid is provided, and this small hole is covered with a backing material made of the same type of resin as the heat-sealable resin layer on the inner surface of the lid. Since the periphery is heat-sealed with this backing material, high sealing reliability can be obtained.

(Example) The present invention will be described in detail below based on specific examples shown in the accompanying drawings.

FIG. 1 showing an example of the heat seal lid of the present invention;
2 and 3, the heat seal lid 1 of the present invention is roughly divided into a lid material 2 and an opening tab 3. As shown in FIG. In the specific example shown in this drawing, the lid material 2 is composed of a laminate of a base 4 such as a metal foil and a heat-sealable resin layer 5 applied to the inner surface of the base (the side that becomes the inner surface when it is packaged). It's on. The lid member 2 consists of a peripheral portion 6 to be heat-sealed and a center panel portion 7, and a rim portion 8 may be formed between the two.

The center panel portion 7 of the lid member 2 is provided with a score 10 that defines a portion 9 to be opened. As shown in an enlarged view in FIG. 3, the score 10 is provided so as to reach from the outside of the lid member 2 to the middle of the base body 4 in the thickness direction.

The opening tab 3 is attached to the gripping ring 11 (Fig. 1).
and a base 12 for attachment to the lid material, and a third
As shown in the figure, an adhesive layer 13 is applied to the outer surface of the lid 2 and to the portion to be opened, that is, the score section 9.
Glued through.

In the specific example shown in FIGS. 1 to 3, the score section 9 has a water droplet shape, and the portion 14 with a large curvature becomes the opening start portion.

In the present invention, the inner adhesive material 15 is adhered to the inner surface of the lid material 2 and in the vicinity of the opening starting portion 14 of the score section 9. An important feature of this inner patch 15 is that it is made of a more rigid material than the opening tab 2, and that one end 16 thereof is positioned so as to substantially overlap the score of the opening opening 14.

That is, according to the present invention, as described above, the opening tab 3 is provided on the outer surface of the portion 9 to be opened, and the inner lining material 15, which is more rigid than the tab, is provided on the inner surface of the opening tab 3 in the shape of a sanderch. Because of the adhesive structure, when the gripping ring 11 of the tab 3 is grasped and pulled upward, the rigid inner lining material 15 is also lifted upward, and the edge 16 of this inner lining material 15 touches the opening starting part 14. It is easy to bite into the thin part of the score and make cuts in the score. Therefore, it is possible to open the package with a single motion.

Moreover, according to the present invention, shearing of the score is started by lifting the relatively rigid inner lining material 15, so there is no need to use a rigid material as the opening tab 3, and the same as the lid material 2. It is possible to use a flexible material or a flexible material rather than the lid material 2, and by this, the characteristics of the lid material and the tab can be matched, and the drop impact resistance and appearance characteristics can be made good. can.

In the present invention, the opening tab 3 must be gripped in a direction opposite to the opening direction (shearing direction of the score 10) with reference to the attachment base 12 to the lid material in order to enable opening to be started by the mechanism described above. ring 11
must be located.

The heat seal lid of the embodiment shown in FIGS. 1 to 3 is
Since the lid material 2 is not provided with openings such as holes, it has particularly excellent sealing performance (sealing reliability).

In FIGS. 4, 5, and 6 showing particularly preferred embodiments of the present invention, a small hole 17 is provided in the vicinity of the opening starting portion 14 of the score section 9. As shown in FIG. 6, the inner patch material 15 is placed on the inner surface of the lid material 2 so that the small hole 17 is completely closed and one end 16 of the inner patch material 15 substantially overlaps the score of the opening starting portion 14. Glue it to the side.

In the specific examples shown in these drawings, the inner lining material 1
5 is made of heat-sealable resin;
Further, it has a considerably larger size than the small hole 17, is well bonded via the inner surface material 5 around the small hole, and is provided so as to bite into the small hole 17.

The opening tab 3 is made of a laminate of a substrate 18 made of, for example, metal foil or metal-deposited mylar film, and a heat-sealing resin layer 19, and is provided on the outer surface of the lid 2 to cover the small hole 17 and to form a small hole. It is adhered so as to firmly adhere to the lining material 15 in the hole.

In this aspect of the present invention, since the opening tab 3 and the inner lining material 15 are directly joined through the small hole 17, the opening tab 3 can be fixed and connected to the lid material 2 extremely reliably. In addition to being strongly implemented,
A secondary advantage is also achieved in that the planned opening portion 9 is lifted upward while being held between the tab 3 and the inner lining material 15, and the opening can be started more reliably and easily. .

In the present invention, a light metal such as aluminum foil is preferably used as the base 4 of the lid 2, but it is of course possible to use iron foil, steel foil, tin foil, etc. In terms of heat sterilization resistance, these metal foils can be pretreated with alumite treatment, boehmite treatment, chemical treatment with phosphoric acid and/or chromic acid, chemical conversion treatment, etc. to form a surface treatment layer. desirable.

The metal foil needs to have some rigidity so that it can be torn with a score, and from this point of view it is desirable to have a thickness of 50μ or more, particularly 80μ or more. The upper limit of the thickness of the metal foil is desirably 200 μm or less, particularly 150 μm or less, from the viewpoint of economy and prevention of damage to fingers etc. when opening the package.

It is important that the score 10 provided on a substrate such as metal foil remains midway in the thickness direction of the metal foil from the viewpoint of gas barrier properties, pressure resistance, drop impact resistance, etc. The depth is in the range of 3/10 to 7/10, especially 2/5 to 3/5, of the thickness of the metal foil from the viewpoint of the above characteristics and ease of opening, and the thickness of the metal foil remaining in the score area is Preferably, the thickness is 20μ or more, particularly 30μ or more.

As the heat-sealable inner material 5, any heat-sealable thermoplastic resin can be used, such as low-, medium- or high-density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-butene-1. Olefin resins such as copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, acid-modified polyethylene or polypropylene, ionically crosslinked olefin copolymers; nylon 11, nylon 12, nylon
13, nylon 6/6, 6 copolymer, nylon 6/
Nylon resins such as 12 copolymers; thermoplastic polyesters such as polybutylene terephthalate, polybutylene terephthalate/isophthalate, and polyethylene/butylene terephthalate/isophthalate are used.

If there is no thermal adhesiveness between the base 4 and the inner material 5, for example if the inner material is made of polyethylene or polypropylene, use a thermosetting adhesive such as an epoxy resin or isocyanate adhesive, or an acid-modified olefin adhesive to bond them together. Laminated and bonded using thermoplastic adhesive such as resin.

The outer side of the metal foil substrate can optionally be provided with a protective coating, which may include any coating consisting of thermosetting and thermoplastic resins; for example modified phenol-epoxy coatings, amino-epoxy coatings, etc. Epoxy paint; for example, vinyl chloride-vinyl acetate copolymer, partially saponified vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, epoxy modified, epoxy amino modified, or epoxy phenol modified −
Vinyl or modified vinyl paints such as vinyl resin paints;
Acrylic resin paint; synthetic rubber paint such as styrene-butadiene copolymer is used. Furthermore, nitrocellulose-based varnishes can also be used effectively.

The lid material in the present invention can be made of various materials in addition to the metal foil laminate described above.
For example, this lid material can be made of a metal-deposited biaxially stretched polyester film as a base, and for applications requiring transparency, saponified ethylene-vinyl acetate copolymer, high nitrile resin, A high gas barrier resin such as a vinyl chloride resin or a vinylidene chloride resin, or a laminate of these high gas barrier resins and a high strength plastic film such as a biaxially oriented polyester film can be used as the substrate.

Furthermore, the lid material may naturally be made of a single layer of the heat-sealable resin as exemplified above.

The lid material can be easily obtained by stamping the various materials described above into a predetermined shape using a press die or the like, and simultaneously engaging the die with a score die attached to the press die. Drilling of the small holes can be done simultaneously with the pressing or separately. When the lid material is a material that does not contain metal foil, score processing is easily performed by heating the score to the softening temperature of the resin.

An advantage of the present invention is that the opening tab 3 can be formed of a material that matches the lid material 2. For example, metal foil, plastic film, metal-deposited plastic film, metal foil can be used, depending on the material constituting the lid material. /Plastic film laminate any material may be used. These can be punched to a predetermined shape to form opening tabs. Of course, the opening tab can also be formed by injection molding plastic.

The inner surface material 15 is formed from the same type of resin as the heat-sealable resin described above. Since this inner surface material 15 is made of plastic, it has excellent corrosion resistance even when it comes into contact with the contents, and furthermore, it can form a strong adhesive bond with the inner surface layer 5 by heat sealing.

The thickness of the inner lining material 15 is sufficient to provide the necessary rigidity for score shearing when opening is started, and it also varies depending on the material of the inner lining material 15 and the thickness and material of the lid material or opening tab. However, it is generally preferred to have a thickness at the end 16 of 0.3 to 5 mm, particularly 0.8 to 3 mm.

The opening tab 3 and the inner lining material 15 may be attached to the lid material 2 by any means as long as they are firmly adhered. For example, these may be bonded using a separate adhesive, or may be bonded by a means called heat fusion. Heat fusion uses high frequency induction heating,
This can be carried out by means such as thermal conduction heating, dielectric heating, infrared heating, and ultrasonic heating.

In the specific example shown in FIGS. 1 to 3, the opening tab 3
is bonded to the lid material 2 via the adhesive layer 13,
This adhesive layer 13 can be made of the heat-sealing resin described above or the thermosetting adhesive described above. Of course, if the opening tab 3 itself is provided with a heat-sealable resin layer, it will be obvious that the adhesive layer 13 may be omitted.

In the embodiment shown in FIGS. 4 to 6, an inner patch material 15 made of a heat-sealable resin is heat-sealed around the small hole 17 of the lid material 2 by means such as ultrasonic irradiation. Next, an unsealing tab 3 is applied, and adhesion to the lid material 2 and inner patch material 15 is performed by means such as high-frequency induction heating. In this case, it is particularly desirable that the resins 5, 16, and 19 be made of the same type of material from the viewpoint of adhesion and sealing properties.

The lid of the present invention can be used for metal cans, plastic containers, metal foil containers, metal foil/plastic composite containers, paper/
The present invention can be advantageously used for sealing various containers such as plastic composite containers, paper/metal foil/plastic composite containers, etc. In particular, the present invention is useful for sealing easily buckling containers to which double seaming cannot be applied, hot filling, It is advantageous for sealing packaging containers that require heat sterilization, etc., and is particularly useful for vacuum forming plastic cups, plug assist forming, pressure forming uniaxially or biaxially stretched plastic cups, drawing forming metal foil containers, etc. Alternatively, it can be suitably used as a heat seal lid for a side seam container made of flexible material.

In FIGS. 7 and 8 showing an example of the above-mentioned preferred application, the container body 20 is filled with the contents hot or cold, the atmosphere is replaced with water vapor, nitrogen, etc. as necessary, and then the container body 20 is covered with a lid. The body 1 is covered with a heat sealant resin film layer 5 on the lid side of the flange 21.
Heat sealing is performed by overlapping the two so that they face each other and heating the flange part under pressure.
This heating temperature is higher than the melting point of the film layer 5, and the pressurization is generally carried out under a pressure of 1 to 10 kg/cm ³ gauge. This heat sealing operation can be easily performed using a heat sealing means known per se, such as a heat seal bar or high frequency induction heating.

The container main body 20 shown in this specific example has a paper substrate 22 and an aluminum foil 23, as shown in the enlarged cross-sectional view of FIG.
are joined via the heat sealant layer 24,
A heat sealant inner surface material 25 is provided on the inner surface.
It is made of a laminate with a heat sealant outer material 26 provided on the outer surface, allowing good heat sealing with the lid of the present invention.

The heat-sealed portion formed using the lid of the present invention can withstand sterilization operations such as hot filling, boiling water sterilization, and retort sterilization, and has a high degree of sealing reliability. It has the advantage that foods can be stored stably for a long period of time, and can be opened easily and reliably.

The excellent effects of the present invention will be explained with the following examples.

Example 1 A laminated material made of 100μ soft aluminum and 50μ low density polyethylene film bonded via acid-modified polyethylene resin was punched out and formed by press to form a flange with an outer diameter of 60mm, a panel with a diameter of 52.3mm, and a depth of 52.3mm. 5
A lid body of mm was obtained. A score defining a water droplet-shaped drinking spout was provided in the center panel of the lid to a depth of 50 μm in the thickness direction of the aluminum foil. Next, an opening tab was attached using nylon adhesive to the outer surface of the lid and to the score section to be opened. The opening tab is made of 12μ biaxially stretched polyester film and 50μ
It has a gripping ring made of laminated aluminum foil. Next, a high-density polyethylene inner patch having a thickness of 2 mm and a diameter of 6 mm was welded to the inner surface of the lid and near the opening start of the score compartment.

The thus produced lid was made by filling a paper cup with an inner surface made of polyethylene with orange juice and thermally bonding it to the flange curl part. When the gripping ring of the opening tab was pulled upward, the opening was easy with an initial opening force of 1.1 kg and a tear opening force of 0.9 kg. There were no feather rings on the cut, and the cut was clean.

Example 2 A lid body provided with a water droplet-shaped score was created from the same materials as in Example 1 and in the same manner. A small hole of 4 mm size was formed using a punch cutter near the opening start part of the score section of this lid, and the hole was completely closed and one end of the hole was placed at a position where it substantially overlapped with the score of the opening start part. The same inner patch material as in Example 1 was heat-sealed to the inner surface of the lid. The inner patch material was placed so as to fit into the small hole.

Next, a 12μ biaxially stretched polyester film,
An opening tab made of three layers of 50μ aluminum foil and 50μ low-density polyethylene film is placed on the outer surface of the lid to cover the small hole, and the low-density polyethylene surface is tightly attached to the lining material inside the small hole. was glued.
When the lid thus obtained was attached to a container similar to that in Example 1 and the opening property was tested, the initial opening force was 1.2.
Kg, tear opening force: 0.9 kg, it was easy to open.
Also, the opening was in good condition with no feather ring or the like.

(Effects of the Invention) In the present invention, a flexible material similar to the lid material or a flexible material rather than the lid material can be used as the opening tab, and thereby the characteristics of the lid material and the characteristics of the tab can be adjusted. By matching, it is possible to create an easy-to-open heat-sealed lid with good drop impact resistance and appearance characteristics. By forming the heat-sealable resin layer with the same type of resin, this backing material can be firmly adhered to the lid material, and this backing material is more rigid than the opening tab. As a result, even if both the tab and the lid are flexible, the point of force applied is fixed near the opening start portion, and the opening operation can be performed smoothly.

Further, in the lid of the first aspect of the present invention, since the lid material is not provided with any openings such as holes, the lid has the advantage of being a heat-sealed lid with particularly excellent sealing performance (sealing reliability). On the other hand, in the lid of the second aspect of the present invention, a small hole passing through the lid is provided, and this small hole is covered with a backing material made of the same type of resin as the heat-sealable resin layer on the inner surface of the lid. Moreover, since the periphery is heat-sealed with this backing material, high sealing reliability can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the easy-open heat seal lid of the present invention, FIG. 2 is a side view of the easy open heat seal lid of FIG. 1, and FIG. 3 is the score of FIG. 2. FIG. 4 is a plan view of an easy-to-open heat-sealed lid that is a preferred example of the present invention, and FIG. 5 is a side view of the easy-to-open heat-sealed lid shown in FIG. 6 is a partial enlarged cross-sectional view of the score portion in FIG. 5, FIG. 7 is a diagram showing the case where the easy-to-open container lid of the present invention is applied to a container, and FIG. 8 is a side wall of the container in FIG. 7. An enlarged cross-sectional view is shown. 1 is a heat-sealable lid, 2 is a lid material, 3 is an opening tab, 4 is a base body, 5 is a heat-sealable resin layer, 6 is a peripheral portion to be heat-sealed, 7 is a center panel portion, 8 is a rim portion, 9 is the part to be opened, 10 is the score, 11 is the gripping ring, 12 is the mounting base,
13 is an adhesive layer, 15 is an inner patch material, 17 is a small hole, 1
8 is a substrate, 19 is a heat-sealable resin layer, 20 is a container body, 21 is a flange, 22 is a paper substrate, 23
24 is an aluminum foil, 24 is a heat sealant layer, 25 is a heat sealant inner surface material, and 26 is a heat sealant outer surface material.

Claims (1)

[Scope of Claims] 1. An easily openable heat-sealable lid for sealing the container body by forming a heat-sealing portion with the container body, the lid being a flexible lid whose at least inner surface is made of a heat-sealable resin layer. A score defining a part to be opened is provided inside the part of the lid to be heat-sealed so as to reach halfway in the thickness direction of the lid, and a flexible material is provided on the outer surface side of the lid and within the score division part. Glue a plastic opening tab near the opening start part of the score compartment and on the inner surface side of the lid, with one end of the opening tab being more rigid than the opening tab and above the opening tab, so that one end thereof is located at the opening start part of the score. An easy-to-open product characterized by a backing material made of the same type of resin as the heat-sealable resin layer being adhered, and the adhesive part of the opening tab and the backing material being adhered to each other in a sandwich-like pattern with the lid material in between. Heat seal lid. 2. An easily openable heat-sealable lid for sealing the container body by forming a heat-sealing portion with the container body, the lid being a flexible lid consisting of a heat-sealable resin layer at least on the inner surface side, A score defining a portion to be opened is provided inside the portion to be heat-sealed so as to reach halfway in the thickness direction of the lid, and a small hole passing through the lid is provided near the opening start portion of the score portion. A backing material made of the same type of resin as the heat-sealable resin layer is placed on the inner surface of the lid and within the score compartment so that one end of the backing material is located at the beginning of the opening of the score and completely closes the small hole. A flexible opening tab is adhered to the outer surface of the lid and in close contact with the lining material inside the small hole, and the lining material is made more rigid than the opening tab. Easy-to-open heat seal lid.