JPH01279057A - Easily openable lid - Google Patents

Abstract

PURPOSE:To prevent the ribbon breakage at the time of opening, by locating the most protruding part of an inner peripheral side guiding weakened line outwardly from the center line, at approximately the same level as or outside of the most protrud ing part of an outer peripheral side guiding weakened line, in the right angle direction from the center line, when viewed outward from the center line. CONSTITUTION:The center line B of a band shaped part 9 protrudes at a right angle to the center line A of an opening piece 12, and then goes across the center line A. A grip 14, which is held by a human hand, is pulled downward along the center line A, and by its opening force, an inner peripheral side guiding weakened line 8 and an outer peripheral side guiding weakened line 7 are gradually sheared at the same horizontal level. When the shear of the weakened line has reached the most protruding part C in the opening starting direction for the inner peripheral side guiding weakened line 8, the part C is located at the same level as the most protruding part D at a right angle to the center line A of the outer peripheral side guiding weakened line 7, or C is located outside of D. Therefore, the working direction of the opening force is changed, and stress concentration to the C point is avoided, and thus the generation of ribbon breakage can be prevented.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an easy-to-open lid, and more specifically, to a full-oven type easy-to-open lid that prevents ribbon breakage and ensures full oven operation. This invention relates to an easy-to-open lid that can be opened easily.

(Prior Art) Conventionally, easy-to-open lids using laminates of metal foil and resin have been widely used as sealing lids for lightweight containers made of metal foil, resin, paper, or laminates thereof. ing. In this easy-to-open lid, a weakened line for opening is provided in the laminate to demarcate the portion to be opened, and a tearing piece is passed to the opening starting portion of the opening portion to break the weakened line, thereby making the seal unsealable. Is going.

Even in this type of easy-to-open lid, there is a demand for a so-called full oven lid in which an opening is formed over almost the entire surface of the lid.
As shown in Figure 5-1 of Publication No. 45, the planned opening portion is divided by the outer circumferential weakened line, and an outer circumferential introduction weakening line and an inner circumferential introduction weakening line are provided, and a band-shaped tear is made from the opening start point. A configuration is generally adopted in which the entire surface is opened after the opening is performed.

(Problems to be Solved by the Invention) However, with this type of fully open type easy-to-open lid, ribbon breakage often occurs when the lid is opened, making it difficult to open the entire lid. Here, ribbon breakage means that the band-shaped part divided by the outer peripheral side weakened line and the inner peripheral side weakened line receives concentration of opening force at the beginning of opening, and the ribbon breaks in the opening direction of the inner peripheral side weakened line. This refers to the phenomenon in which the area is cut off from the vicinity of the most protruding part. This ribbon breakage is a phenomenon that cannot be avoided with easy-open lids for cans made of aluminum sheets, and is a problem specific to lids made of a laminate of metal foil and resin.

Therefore, an object of the present invention is to prevent ribbon breakage in an easy-to-open lid for a metal foil-resin laminate of the type described above;
To provide a lid whose entire surface can be opened reliably and smoothly without failure.

(Means for solving the problem) According to the present invention, the lid body, the outer peripheral weakening line provided on the lid body,
The opening planned area is divided by the outer peripheral weakening line, the outer peripheral side introduced weakening line that reaches the outer peripheral weakened line provided in the opening planned area, the inner peripheral side introduced weakened line that does not reach the outer peripheral weakened line, the outer peripheral side introduced weakened line and the inner periphery. an unsealing start part and a band-shaped part separated by a side introduction weakening line;
and an opening piece coupled to an opening starting part, and the opening piece and the band-like part protrude so that the center line of the band-like part becomes convex in a direction perpendicular to the center line of the opening piece, and then the center line is The part of the inner peripheral side introduced weakening line that is arranged to cross the line and that projects most outwardly from the center line is at approximately the same level as the most protruding part of the outer peripheral side introduced weakening line in the direction perpendicular to the center line, or An easily openable lid is provided, which is characterized by being located outwardly.

(Function) The easy-to-open lid of the present invention has the following structural features regarding the arrangement of the opening piece and the strip.

■ From the most protruding part of the inner circumferential introduction weakening line in the opening starting direction to the opening starting part side, the entire center line of the band-shaped part is
It is located closer to the outer peripheral introduction weakening line than the center line of the unsealing piece.

■ The outer peripheral side introduction weakening line bulges in a convex direction toward the outer peripheral side introduction weakening line when viewed from the center line of the opening piece in a direction perpendicular to the opening start direction.

■ The most protruding part of the inner weakened line in the opening direction is at approximately the same level as the most protruding part of the outer weakened line in the direction perpendicular to the opening direction, or is positioned outwards. do.

According to the present invention, these features make it possible to prevent the ribbon from breaking during opening and to smoothly and reliably open the entire lid. This will be explained below.

FIGS. 1 and 2 show typical examples of the easy-to-open lid of the present invention.
In the figure, this lid body 1 includes a metal foil 2 and a resin film 3.
It is formed from a laminate of. An outer peripheral weakening line 4 is engraved on the lid body 1, and an opening portion 5 is provided inwardly from the outer peripheral weakening line 4, and a heat-sealing peripheral edge portion 6 is provided outwardly from the opening portion 5. In the planned opening portion 5, there is a weakened line 4 on the outer periphery from approximately the center of the lid.
An outer peripheral side introduced weakened line 7 that reaches the outer peripheral weakened line 4 and an inner peripheral side introduced weakened line 8 that does not reach the outer peripheral weakened line 4 are provided, and the belt-shaped portion 9 is divided by both introduced weakened lines 7 and 8. In this specific example,
The inner peripheral side introduction weakening line 8 has a diameter smaller than the outer peripheral weakening line 4 and has a circumferential extension (weakening line) 10 concentric therewith.

An unsealing start portion 11 is provided at the starting ends of both lead-in weakening lines 7 and 8. In this specific example, the unsealing initiation part 11 consists of a small hole punched in the shape of a "<" character. An unsealing piece 12 is provided to cover the "<"-shaped small hole from the outside, and an inner adhesive material 13 is provided to cover the "<"-shaped small hole from one side.
is provided, and the small hole 11 is sealed by fusing the unsealing piece 12 and the inner patch 13. A grip portion 14 is formed at the end of the opening piece 12 .

Further, the end portion of the band-shaped portion 9 and the opening piece 12 are bonded together by means such as thermal bonding.

The opening piece 12 has a center line A, and the direction of this center line A is the opening start direction. On the other hand, the strip portion 9 has a center line B,
This center line B can be defined as a curved line or a straight line obtained by connecting the midpoints of line segments in the direction across the strip.

From FIG. 1, the center line B of the strip 9 once protrudes so as to be convex in a direction perpendicular to the center line A of the opening piece 12, and then
It will be understood that the arrangement is such that it crosses the center line A.

Further, referring to FIG. 1, the inner peripheral side introduction weakening line 8 includes:
There is a part C that most protrudes outward from the centerline A, and there is also a part C that protrudes the most in the direction perpendicular to the centerline A on the outer peripheral side introduction weakening line 7, but in the present invention, both of these parts are When viewed in the outward direction of A, the arrangement relationship is such that C is at the same level as D, or C is located further outward than D. On the other hand, the conventional general shape of the weakening line is as shown in FIG. 9, for example, in which the center line B of the strip is perpendicular to the center line A of the opening piece It does not protrude convexly, does not cross the center line A, and the part C that protrudes most outward from the center line of the inner weakened line is perpendicular to the center line of the outer weakened line. The shape of the line of weakness is such that it is located inward from the most protruding part in the direction of the center line.

Examining the process of cutting the weakened line in FIG. 9, it can be seen that the process is as described above. That is, the grip part 14 pinched by a human hand is pulled downward in the figure along the center line A of the opening piece, and the opening force causes the inner peripheral side introduction weakening line 8 and the outer peripheral side introduction weakening line 7 to move downward in the figure. They are sequentially cut at the same horizontal line position in . When the cutting of the weakening line reaches the most protruding part C in the opening start direction of the inner peripheral side introduction weakening line 8, if the direction in which the opening force acts does not change and it continues to act in the opening start direction, 0 A "ribbon break" occurs in which the unsealing force is concentrated at a point and the strip 9 is cut from the zero point.

With the conventional shape of the weakening line, ribbon breakage is likely to occur due to this process, but by improving the shape of the weakening line in the present invention as described above, the opening force acts on the ribbon for the following reasons. It is believed that by changing the direction, stress concentration at the zero point is avoided, and ribbon breakage is prevented.

In FIG. 3, which shows the state in which the lid of the present invention is being opened, the opening force is applied by a human hand in the outward direction of the center line A of the opening piece, but this force is applied to the inner peripheral side with respect to the weakening line. It acts as a force that attempts to cut the lead-in weakened line 8 and the outer peripheral side lead-in weakened line 7.

Among the combined forces applied to these lines of weakness, the forces effective for cutting the lines of weakness are a shearing force in the thickness direction and a tensile force in the direction normal to the lines of weakness that acts within the lid surface.

When the opening force acts away from the cutting point of the weakening line, the farther the cutting point of the weakening line is from the center line A, and the closer the angle between the center line A and the tangent at the cutting point of the weakening line is to a right angle. The tensile force component in the composite force becomes larger.

In FIG. 1, as described in the structural feature (■), the center line B of the strip portion 9 is closer to the opening start portion than the portion C.
Since the entire opening piece is located closer to the outer circumferential introduced weakened line 7 than the center line A of the opening piece, the outer circumferential introduced weakened line 7 is always located farther from the center line A than the inner circumferential introduced weakened line 8. In addition, as described in the structural feature ■■, the shape of the outer peripheral side introduction weakening line 7 is convexly bulged outward in the direction perpendicular to the center line A.
In addition, since part C is located at approximately the same level as part C when looking outward from center line A, or is located outwardly, in the initial stage of opening until part C is reached as shown in FIG. The tensile force component in the composite force acting on the cutting point of the line 7 is always larger than the tensile force component acting on the inner peripheral side introduced weakening line 8.

When the weakening line is cut, an inertial force as a reaction is transmitted to the hand of the person applying the opening force, but the direction is the normal direction of the outer peripheral side introduced weakening line 7 toward the center line A side.

In addition, as the cutting of the weakening line approaches the level of part C, the tensile component of the composite force acting on the outer peripheral side introduced weakening line 7 tends to decrease, so the inertial force is not canceled out and, for example, as shown in FIG. In this case, a rotational force is generated that cuts the strip 9 clockwise. On the other hand, when the level of the part C is exceeded, the direction of the outer peripheral side introduction weakening line 7 changes toward the center line A, and at the same time, near the level of the part C, the inner peripheral side introduction weakening line 8 changes to the center line A of the opening piece. Since it changes away from the outer peripheral side introduction weakened line 7 due to the above-mentioned rotational force, the outer peripheral side introduction weakened line 7 is cut before the inner peripheral side introduction weakened line 8, and the band-shaped part 9 is opened smoothly in a clockwise direction. Therefore, it is considered that the unsealing force is not concentrated on the 0 point that is most protruding in the unsealing start direction, and ribbon breakage is prevented. (Preferred Embodiment of the Invention) The lid shown in FIGS.
The part C that most protrudes outward from the center line (opening start direction)
This is an example in which the most protruding portion of the outer peripheral side introduction weakening line 7 in the direction perpendicular to the center line is at approximately the same level.

Of course, in the easy-to-open lid of the present invention, as shown in FIG. It may be located further outward from the center line than the most protruding portion in the right angle direction.

In the easy-open lid explained so far, the center line A of the opening piece is located at the lid body 1.
However, as shown in FIG. 5, it goes without saying that the opening piece center line A may be offset from the center of the lid body 1.

In the present invention, the arrangement of the outer peripheral side introduced weakened line 7 and the inner peripheral side introduced weakened line 8 can be variously changed within the above-mentioned limited range. For example, the inner peripheral side introduction weakening line 8 is the opening piece center line A
As shown in FIG.
(Fig. 1), or may be provided so as not to protrude toward the outer peripheral side introduction weakening line 7 side, but to be in contact with the opening piece center line A (Fig. 1).

In the easy-open container lid of the present invention, the outer peripheral side introduced weakening line 7
The distance aβ between the part and the center line A of the unsealing piece has a ratio of 11/Ft of 0.35 to O, aO, especially 0.50 to 0.70, where R is the radius of the outer peripheral weakening line. , and the distance @m between the portion C of the inner peripheral side introduction weakening line 8 and the opening piece center line A is such that the m/R ratio is 0.05 to 0.45, particularly 0.10 to 0.35, and m /IL ratio is 0.05 to 0.
70, particularly 0.20 to 0.55.

Also, the distance between the part and part C in the direction of the opening piece center line A @n
The ratio of n/R is preferably from 0 to 40, particularly from 0 to 30.

In the easy-to-open lid of the present invention, the opening piece can also be fixed to the lid body with rivets. In FIGS. 7 and 8 showing this aspect, the starting ends of the outer peripheral side introduced weakened line 7 and the inner peripheral side introduced weakened line 8 are connected to each other to form a large curvature portion 15. A small hole 11' is provided at the center of the hole. The rivet 16 of the opening piece 12 is inserted into this small hole 11', and the end 17 is expanded, and the lid 1
The unsealing piece 12 is fixed and sealed by being fused and bonded to the resin layer 3 of.

Lid Constituent Materials and Manufacturing Method In the present invention, light metal foil such as aluminum foil is preferably used as the metal foil for the laminate, but it is of course possible to use iron foil, steel foil, tin foil, etc. . These metal foils are anodized, boehmite treated, phosphoric acid and/or
Alternatively, it is desirable from the viewpoint of heat sterilization resistance that the material be pretreated with chemical treatment such as chromic acid or chemical conversion treatment.

The metal foil needs to have some stiffness so that it can be torn at the score, and from this point of view, 30
It is desirable to have a thickness of μm or more, particularly 50 μm or more. The upper limit of the thickness of the metal foil is 200 μm or less from the viewpoint of economy and prevention of damage to fingers etc. when opening the package.
In particular, it is desirable that the thickness be 150 μm or less.

As the resin of the laminate, resin having heat sealability,
For example, low-1 medium or high-density polyethylene, tactical polypropylene, propylene-ethylene copolymer, propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate. Olefin resins such as copolymers and eitzmer are used. These resins generally have a thickness of 5 to 10
The thickness is preferably 0 μm, particularly in the range of 10 to 70 μm.

The resin and metal foil can be laminated using, for example, a urethane adhesive, an epoxy adhesive, or an acid-modified olefin resin adhesive.

The laminate can have the above-described layer structure of two or more layers, and for example, a paper layer or a resin protective layer can be provided on the surface of the metal foil. As the resin protective layer, high-strength plastic films such as biaxially oriented polyester film, biaxially oriented polypropylene film, and biaxially oriented nylon film, epoxy-phenol paint, epoxy-urea paint, epoxy-melamine paint, and vinyl paint can be used. , acrylic paint, epoxy-acrylic paint, etc. are used.

The laminate is press-formed (draw-formed) and formed into a lid by punching, forming a peripheral curled portion, and drawing a panel portion, and then engraving and perforating a score on the metal foil.

“Alternatively, the laminate can be first perforated and scored, then the opening piece and inner liner can be attached, and then punched out and formed into a lid.” The score on the metal foil is From the viewpoint of gas barrier properties, pressure resistance, drop impact resistance, etc., it is important that the metal foil stays in the middle of its thickness, and its depth is determined by the above properties and ease of opening. 3 of the thickness of metal foil from the standpoint of
It is preferable that the thickness of the metal foil is in the range of /1o to 7/10, particularly 215 to 315, and the thickness of the metal foil remaining in the score portion is 10 μm or more, particularly 20 μm or more.

The opening piece may be a tab-type one made of a laminate with a layer structure similar to that described for the lid, or a rivet-attached opening piece molded from an olefin resin similar to the inner surface material of the lid. used.

It is advantageous to use a thermal bonding method such as heat fusion to fix the unsealing piece, but it goes without saying that bonding and fixing can also be carried out using an adhesive or the like.

The lid of the invention can be used for any container, e.g. paper-plastic
It is advantageously used as a heat seal lid for sealing aluminum foil composite containers, metal cans, wide mouth bottles, plastic cup containers, metal foil containers, metal foil/plastic composite containers, etc. by heat sealing. In particular, the present invention is advantageous for sealing easily buckling containers to which double seaming can be applied, and packaging containers that require treatments such as hot filling and heat sterilization. It is suitably used as a heat seal lid for a cup, a uniaxially or biaxially stretched plastic cup made by plug assist molding, pressure forming, etc., a metal foil container made by drawing molding, etc. The most typical examples of such uses include containers made of aluminum foil or steel foil with heat-sealable resin film layers on their inner and outer surfaces, and composite cans and cup-shaped containers made of paper and metal foil. One example is the cover for this.

(Effects of the Invention) According to the present invention, the lid body, the outer peripheral weakening line provided on the lid body,
The opening planned area is divided by the outer peripheral weakening line, the outer peripheral side introduced weakening line that reaches the outer peripheral weakened line provided in the opening planned area, the inner peripheral side introduced weakened line that does not reach the outer peripheral weakened line, the outer peripheral side introduced weakened line and the inner periphery. an unsealing start part and a band-shaped part separated by a side introduction weakening line;
and an easy-to-open lid consisting of a tear piece connected to an opening start part, after the tear piece and the strip are protruded so that the center line of the strip is convex in a direction perpendicular to the center line of the tear flap. It is arranged to cross the center line, and the part of the inner peripheral side introduced weakening line that most protrudes outward from the center line is approximately the same as the most protruding part of the outer peripheral side introduced weakened line in the direction perpendicular to the center line. By positioning them at the same level or outward, rotational force is applied to the strip that is being cut, and stress is prevented from concentrating on the most protruding part of the weakened line on the inner peripheral side, thereby preventing ribbon breakage. This makes it possible to open the entire surface of the lid reliably and smoothly without failure.

(Example) Example 1 A soft aluminum foil with a thickness of 50 μm is prepared, the outer surface of which is coated with an epoxy/phenol paint with heat-sealing properties, and the inner surface of the aluminum foil is painted with a thickness of 65 μm.
A lid material was manufactured by extruding and laminating a polypropylene film of 1.5 m.

The lid material was punched out to a diameter of 80 mm to create a disc, and a small hole in the shape of a "<" was punched in the center of the disc. To connect to the tip of the "<"-shaped small hole, a weakened line was engraved on the surface side of the lid material by press processing so that the remaining thickness of the weakened line was approximately 20 μm. A lid body having a shape as shown in Fig. 1 was created.

The shape of the weakened line is such that the most protruding part of the inner weakened line in the opening direction is located at approximately the same level as the most protruded part of the outer weakened line in the direction perpendicular to the opening direction. It looks like it will.

A soft aluminum foil with a thickness of 9 μm is prepared, and a biaxially stretched polyester with a thickness of 12 μm is pasted on one side of the aluminum foil using an adhesive, and a polypropylene film with a thickness of 50 μm is extruded and laminated on the other side. ,
It will now be 20mm wide.

An opening strip having a length of 35IIffl was cut. In addition, a polypropylene film with a thickness of 50 μm was prepared, and an inner lining material with a diameter of 18 ml was made from it. "<" of the lid body
Place the unsealing piece on the outer surface of the lid in such a way as to cover the small hole in the shape of a ``.'' At the same time, place the inner material on the inner surface of the lid while covering the small hole, with a heat-resistant rubber plate with a thickness of 1 mm.
In addition, the opening pieces are placed facing each other with a heating plate heated to 200°C, and the outer surface of the lid body and the opening piece are attached in such a manner that they form a peelable seal. Heat sealing was completed to form a tight seal between the inner lining material and the inner lining material.

By this heat sealing, the opening piece was joined to the opening initiation part, and an easy-open container lid according to the present invention as shown in FIG. 1 was created.

Approximately 80mm thick is made by deep drawing a laminate made by extruding and laminating polypropylene on the inner and outer surfaces of a 75μm thick steel foil.
After hot filling corn soup into a cylindrical cup-shaped container having an internal volume of cc, the easy-open container lid of this example was heat-sealed to the container. After sterilizing it in a retort at 115°C for 50 minutes, the unsealability was evaluated when the unsealed piece was held in the hand and opened in the direction of the center line of the unsealed piece (intensity of occurrence of ribbon breakage).
are shown in Table 1.

Example 2 An easy-open container lid according to the present invention as shown in FIG. 4 was prepared using the same materials and procedures as in Example 1. The shape of the weakened line is such that the most protruding part of the inner peripheral weakened line in the opening start direction is further outward when viewed in the opening start direction than the most protruded part of the outer peripheral side weakened line in the direction perpendicular to the opening start direction. It seems to be located.

Openability evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 A disk with a diameter of 80 mm was punched out from the same lid material as in Example 1 by press working, and a diameter of 4ffII1 was stamped in the center of the disk.
A small circular hole of No. 1 was punched by press working.

The same weakening lines as in Example 1 were carved on the outer surface of the disc, except for the weakening lines near the circular small holes, to create a lid as shown in FIG. 7. A polypropylene opening piece having a cylindrical rivet part with a diameter of 3.9 mm and a length of 4 mm that can be fitted into the small circular hole and a ring part into which the index finger can be inserted is made by injection molding, and the lid body is After fitting the rivet part of the unsealing piece from the outer surface of the lid, the head of the rivet protruding from the inner surface of the lid is crushed with a hot plate heated to 200°C and welded to the polypropylene on the inner surface. Figure 3
An easy-to-open container lid according to the present invention as shown in FIG.

Openability evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 Using the same materials and the same procedure as in Example 1, an easy-open container lid as shown in FIG. 9 was prepared.

Openability evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

From the above results, it can be seen that ribbon breakage is improved in the ribbon according to the present invention compared to the comparative example.

Chapter 1 Table

[Brief explanation of the drawing]

FIG. 1 is a top view of an example of the easy-to-open lid of the present invention, FIG. 2 is a sectional view taken along line II-II of the lid in FIG. 1, and FIG. 3 is a state in which the lid is being opened in FIG. FIG. 4, FIG. 5, and FIG. 6 are top views showing several examples of the arrangement of lead-in weakening lines in the easy-to-open lid of the present invention, and FIG. FIG. 8 is a top view showing another aspect of the unsealing initiation part of the unsealable lid, FIG. 8 is a cross-sectional view taken along the line ■-■ of the lid in FIG. 7, and FIG. 9 is an example of the lid other than the present invention. FIG. 1 is a lid, 2 is a metal foil, 3 is a resin, 4 is an outer peripheral weakened line, 5 is an opening planned area, 6 is a peripheral edge for heat sealing, 7 is an outer peripheral side lead-in weakened line, 8 is an inner peripheral side lead-in weakened line, 9 is a band-shaped part, 10 is an extension of the inner peripheral side introduction weakening line, 11 is an opening start part, 12 is an opening piece, A is an opening piece center line, B is a belt-shaped part center line, C is an inner peripheral side introduction weakening line , D indicates the most protruding part in the direction A, and D indicates the most protruding part in the direction perpendicular to A of the weakened line introduced on the outer peripheral side.

Claims (1)

[Claims] (1) Lid body, outer peripheral weakened line provided on the lid body, planned opening area divided by the peripheral weakened line, outer peripheral side introduction weakened line that reaches the outer peripheral weakened line provided in the planned opening area, and reaches the outer peripheral weakened line. It consists of an opening start part and a band-shaped part, which are divided by an inner peripheral side introduced weakened line, an outer peripheral side introduced weakened line and an inner peripheral side introduced weakened line, and a tear piece connected to the opening start part, and the opening piece and the belt-shaped The part is arranged so that the center line of the strip protrudes in a direction perpendicular to the center line of the opening piece, and then crosses the center line, and extends outward from the center line of the weakened line introduced on the inner peripheral side. An easy-to-open lid characterized in that the most protruding part is located at approximately the same level as the most protruding part in the direction perpendicular to the center line of the outer peripheral side introduction weakening line or located outward from the center line.