JPS62292229A - Manufacture of easily opening property cover - Google Patents

Abstract

PURPOSE:To obtain a score protection type easily opening property cover which is not only excellent in its safety, rust resistance and corrosion resistance, but also excellent in its external appearance characteristic, by engraving and providing one line of score and performing the coating of a score cut end edge protective resin, and sticking and fixing an unsealing tab. CONSTITUTION:A score 8 is provided so as to reach the middle part in the thickness direction of a metallic material 2, and on the outside surface side of a can cover, a score cut end edge protective resin covered zone 12 consisting of elastomer is provided so as to cross the score 8. The resin covered zone 12 is filled to the inside of the unsealing score 8, and also, adheres closely to both its sides, as well. An unsealing tab 13 has a score push-tearing tip 14 in one end, and has a holding part and a supporting point part 16 which is positioned between them and joined to the cover, in the other end. The push- tearing tip 14 of the tab 13 is fixed by being brought to thermals adhesion through an opening part of a cover body and a thermoplastic resin adhesive agent layer 19, in a tongue piece-shaped supporting point part 16, so that its position coincides roughly with the score 8 of the cover body.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing an easy-to-open lid, and more specifically, it relates to a method for manufacturing an easy-to-open lid, and more specifically, to prevent damage caused by a broken score when opening the lid. The present invention relates to a method for producing an easy-to-open lid that has excellent protection and antirust properties for the score portion.

(Prior Art) Conventionally, as an easy-to-open wrapping for cans, what is generally called a full open can is known. This bag is equipped with an opening score that demarcates the part that should be opened, and an opening tab is provided in the part that should be opened, and when opening the bag, the score is sheared and the part that should be opened is It is removed from the surrounding area. There is a sharp cut edge around this removed part, and accidents often occur where fingers are injured by touching this edge.

Many proposals have been made to prevent the above-mentioned injuries by covering the sharp sheared edges formed by score cutting with a resin coating band applied to the binding in advance. Publication No. 54-20907 discloses that a cutting groove (score) for breaking is carved in the lid material by press working, a handle attachment part (opening tab) is integrally molded, a sealing agent is applied to the seaming part, A method for producing an easily openable container, which consists of preheating the lid plate, applying a heat-molten sensuous material over and around the kerf, and then covering the container body with the lid plate and tightening it. is listed.

(Problem to be Solved by the Invention) The opening tab of a conventional easy-open lid is fixed by riveting, and this process is generally performed in the order of bubble, bubble reform, button, score, and stake. This is essential for preventing damage to the score and positioning it, and for this reason, it was necessary to apply a protective resin to the score after the opening tab was attached.

However, since it is necessary to position the pressing tip (nose) of the opening tab above the score at the opening start point, it is not possible to provide an organic resin coating on the score section below this pressing tip. However, it was difficult to completely cover the entire score area. For this reason, the protection of the cut edge after the score is broken is incomplete, and problems such as rusting and pitting occur in the uncoated score portion.

In order to speed up the coating of resin coatings, it is necessary to increase the rotation speed of the lid or lining gun and finish the application in a short time. This results in uncoated areas in the shaded areas, which poses problems in terms of safety, rust prevention, and corrosion resistance of the score.

In addition, during the organic resin application process, resin is also applied to the tip of the opening tab, and when the rotation speed of the lid or lining is increased, some of the resin that collides with the tab is blown off and adheres to the chuck wall of the lid. This will have a negative impact on subsequent processes, especially the process of tightening the lid.

Furthermore, in the spin coating process described above, the distance between the gun nozzle tip and the lid must be at least equal to the thickness of the tab, but if the rotation speed of the lid or lining gun is increased,
The organic resin just before it adheres to the lid is scattered outward by centrifugal force,
The width of the organic resin coating band is no longer uniform, resulting in poor appearance and a significant reduction in commercial value.

Therefore, the present invention eliminates the above-mentioned drawbacks in the conventional manufacturing method of the conventional score-protected easy-open lid, and the entire score is completely covered with a protective resin coating band, which improves safety, rust prevention, and corrosion resistance. It is an object of the present invention to provide a method for manufacturing a score-protecting type easy-to-open lid that has excellent appearance characteristics.

(Means for Solving the Problem) The score-protected easy-opening lid is manufactured in the following process order: molding the lid material into a lid, and forming at least one score that demarcates the part to be opened in the mirror lid. a step of engraving, and a step of applying a resin coating for protecting the cut edge of the score, which also serves as rust prevention, so as to completely cover the score and straddle the score, prior to fixing the opening tab; It has been found that the second object can be achieved by performing the step of adhesively fixing the opening tab to the part to be opened so that the tip of the mold is positioned on the coated score or in the vicinity thereof.

(Function) According to the present invention, by attaching and fixing the opening tab to the lid by adhesive, each process of rivet formation (valve, valve reform, button and stake) is unnecessary, and the opening tab Since the strictness of positioning is relaxed, it is possible to separate the score engraving process and the opening tab fixing process, and an organic resin coating is applied between the score engraving process and the opening tab fixing process. It becomes possible to provide a band application process.

Furthermore, since the organic resin coating band is applied prior to fixing the opening tab, it is possible to form a complete coating band with uniform thickness and width over the entire circumference of the score.

In addition, when the lid or lining gun rotates at high speed to speed up the coating process, since there are no tabs, there is no shadow from the tabs, which maintains the integrity of the coating and improves the application process. This also eliminates the possibility of the organic resin being flicked off by the tab. Furthermore, since there are no tabs, the distance between the lining gun/nozzle and the lid can be made sufficiently close, making it possible to form an organic resin coating band within the intended pattern and dimensions.

(Actions and Effects of the Invention) According to the present invention, due to the above-mentioned effects, the entire score is completely covered with the protective resin coating band, and the score is excellent in safety, rust prevention, and corrosion resistance, and also has excellent appearance characteristics. A protective easy-open lid can be provided. In addition, 1. E-readable easy-opening lids can be manufactured at high speed and with a reduced number of steps.

(Preferred embodiment of the invention) In FIG. 1 showing the top surface of the lid obtained in the first step, FIG. 2 showing its side cross section, and FIG. As shown in FIG. 3, it has a cross-sectional structure consisting of a metal material 2, an outer protective coating 3a applied to the entire outer surface thereof, and an inner protective coating 1113b applied to the entire inner surface thereof.

This lid 1 has a circumferential groove portion 4 on the outer periphery and an annular rim portion (
A sealing compound layer 7 is provided in the groove 4 to be sealed with the can body flange (not shown) during double seaming with the can body flange (not shown). It is provided. Inside the annular rim portion 5 there is a portion 9 to be opened, demarcated by scores 8 . This opening portion 9 may substantially coincide with most of the panel portion 6, or a portion of the panel portion 6 may be the opening portion. As shown in the enlarged sectional view of FIG. 3, the score 8 is provided so as to reach the middle of the metal material 2 in the thickness direction. Although the score 8 is broken when the package is opened, a second varnished core 10 may be provided inside and/or on the outside of the score 8 for opening in order to reduce the residual thickness of the score 8.

In the specific example shown in the drawings, a second varnished core 10 is provided inside the score 8 that partitions the opening portion 9, and a rim portion or step portion 11 is further provided inside at a smaller interval than the second varnished core. .

The molding and score imprinting on the lid shown in FIGS. 1 to 3 can be performed using a press apparatus for wrap-around molding that is known per se. The sealing compound layer 7 is formed by applying an aqueous latex or solution of the sealing compound to the groove of the rotating lid through a lining nozzle and drying it. It should be understood that this step of applying the sealing compound can be performed at any stage, such as between the first and second steps, between the second and third steps, or after the third step. .

In FIG. 4 showing the top surface of the lid obtained in the second step, FIG. A resin coating band 12 made of elastomer for protecting the cut edge of the score is provided. This resin coating band 12 is provided over the entire circumference of the score 8, and as clearly shown in FIG. It is provided with a relatively wide width so as to completely cover the varnish core lO and the rim portion 11. Further, the resin coating band 12 is filled inside the opening score 8 and is also in close contact with both sides of the opening score 8.
It will be understood that the coating also functions as a rust-preventing and anti-corrosion coating for the varnish core lO.

The protective resin coating band shown in FIGS. 4 to 6 is applied using a lining gun as shown in FIGS. It is formed by applying it to the lid and solidifying the resin.

In FIG. 7 showing the top surface of the lid obtained in the third step, FIG. 8 showing a side cross section thereof, and FIG. 9 showing an enlarged cross section of the main part, this opening tab 13 has a score stamping tip at one end. 14, it has a grip part (ring) 15 at the other end and a fulcrum part 16 located between them and joined to the lid. In this embodiment, the fulcrum portion 16 includes a generally U-shaped cut 1 in the tab between the tip 14 and the ring 15.
7 is formed into a tongue shape with a connecting portion 18 between the fulcrum portion 16 and the tip 14. The tearing tip 14 of the opening tab 13 is attached to the opening portion 9 of the lid and the thermoplastic resin adhesive at the tongue-shaped fulcrum portion 16 so that its position almost matches the score 8 of the lid. It is fixed by thermal bonding via layer 19.

The lid body shown in FIGS. 7 to 9 is produced by pressing the lid body 1 and the fulcrum portion 16 of the opening tab 13 under conditions where the adhesive layer 19 located between them is in a molten state, and then applying heat. It is obtained by cooling and solidifying adhesive 7919 under pressure. In this process, the adhesive layer 19 is heated and melted in a very short time by applying high-frequency induction heating to the corresponding part of the lid, while the heat is melted by continuing to press with the power cut off. Heat dissipation causes cooling and solidification of the adhesive within a relatively short period of time.

When opening the binding shown in FIGS. 7 to 9, when the ring 15 of the opening tab 13 is picked up with a finger and lifted upward, this force is directed downward to the mold tip 14 via the fulcrum portion 16. A downward pressing force is applied to the score 8, and shearing of the score 8 begins.0 Next, by further lifting the opening tab 13, the opening portion 9 is also lifted upward, and the score 8 As the shearing progresses further,
The opening portion is removed. In FIG. 10 illustrating this stage during opening, it can be seen that at the time of shear opening with a score of 8, there is a step between the opening portion 9 and its outer peripheral portion 20. The aforementioned varnish core lO and rim part 1
1 has the function of engaging with the resin coating band 12 to prevent the coating band 12 from being pulled and moved in the radial direction and fixing it. Due to the step formed between the portion 9 and its outer circumferential portion 20, peeling progresses between the portion 22 and the outer circumferential portion 20 that protrudes outward from the cut edge 21 of the opening portion of the covering band 12. , and it will be appreciated that this protruding portion 22 acts as a protector to prevent finger contact with the cutting edge 21.

The metal material forming the binding may be a laminate of a surface-treated steel plate, an aluminum plate, or a metal foil such as aluminum foil and a resin film, but in the present invention, a rigid and sharp cut edge is easily formed. Surface-treated steel sheets that are particularly useful for easy-open end caps made of surface-treated steel sheets include electrolytic chromic acid treated steel sheets (TFS), tin-plated steel sheets (tinplate), nickel-plated steel sheets, tin-nickel alloy plated steel sheets, and aluminum-plated steel sheets. Examples of metal materials include, but are not limited to, steel plates, etc. Generally, metal materials have a 0. lO~0.40
A layer having a thickness of 0.12 to 0.35 mm is particularly preferable.

As the protective coating, any known protective coating that exhibits excellent adhesion to the metal materials mentioned above may be used. Examples of this paint include thermosetting or thermoplastic resin paints, such as modified epoxy paints such as phenol-epoxy paints, amino-epoxy paints, and epoxy-ester paints; for example, vinyl chloride-vinyl acetate copolymers, vinyl chloride-acetic acid copolymers, etc. Vinyl or modified vinyl paints such as partially saponified vinyl copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, epoxy-modified, epoxyamino-modified, or epoxyphenol-modified vinyl resin paints; acrylic resin paints; Oil-based paints; alkyd paints; polyester paints; synthetic rubber-based paints such as styrene-butadiene copolymers, etc. are used.

Typical primer paints with excellent adhesion and corrosion resistance are phenol-epoxy paints made of resol-type phenol-aldehyde resins derived from various phenols and forlarbite, and bisphenol-type epoxy resins. In particular, it is a paint containing a phenol resin and an epoxy resin in a weight ratio of 90:10 to 5:95. This paint also has excellent workability, and has the advantage that even when subjected to score processing, the score processed portion (back side of the score) has good corrosion resistance. This type of paint also has excellent adhesion to the polyamide adhesive used to fix the tab.

Another typical example of a wI-retaining paint with excellent adhesion and corrosion resistance is a vinyl chloride copolymer resin paint having a polar group. This paint contains polar groups such as carboxyl groups, acid anhydride groups, and epoxy groups at a concentration of 50 to 2000 mmol per 100 g of resin, and contains polar groups such as acrylic acid, methacrylic acid, maleic anhydride, acrylic acid, or methacrylic acid. It is a paint containing a resin obtained by copolymerizing acid hydroxy-propyl or ethyl ester, glycidyl acrylate (methacrylate), etc. with vinyl chloride, optionally with other comonomers such as vinyl acetate.

Hydroxyl groups can also be supplied by saponifying vinyl acetate units in the copolymer, and epoxy groups can also be supplied by modifying the copolymer with an epoxy resin or epoxyphenol paint.

Of course, these coating films may have a single layer structure, or may have a multilayer structure such as a combination of a base coat and a top coat.

Furthermore, it is of course possible to print on the base coat and apply a finishing varnish thereon.

The thickness of the coating film is not particularly limited as long as the above-mentioned purpose is achieved, but generally speaking, it is preferably in the range of 0.2 to 30 pm, particularly 1 to 20 pm.

The opening tab may be made of the same kind of material as the material constituting the binding or a different kind of material. For example, it may be formed from a light metal plate such as aluminum or an aluminum alloy, or it may be formed from a surface-treated steel plate. Further, it may be made of a plastic material as long as it has sufficient rigidity.

When fixing the opening tab with a thermoplastic adhesive, a resin containing an amide repeating unit and/or an ester repeating unit is preferable, and a resin having a melting point or softening point in the range of 50 to 300°C, particularly 80 to 270°C is used. Polyamides, copolyesters, or blends of two or more thereof are used.

An opening score of 8 means that the residual thickness in the score part is 178 to 1/2 of the thickness of the base plate, and the absolute thickness is 0.2 to 0.
．． It is desirable that the thickness be 9 layers, particularly in the range of 0.3 to 0.8 layers.

On the other hand, the second varnish core, which serves as the binding-resin coating band engagement mechanism,
The dimensions should be such that it is possible to fill the resin and hold the two together, and the width of the opening of the score is 0.03 mm or more, preferably 0.05 mm or more, and more preferably 0.0 mm.
It is desirable that the fog layer is 7 or more, and the taper angle of the score is in the range of 150 degrees or less, especially 135 degrees or less.
In addition, the step dimension of the rim part or step part that becomes the engagement mechanism is 0.
．． 10 to 1.00mm, especially 0.15 to 0.80■
It is desirable that the angle be within the range of about 100 degrees, and the angle made with respect to the horizontal plane is preferably 20 to 90 degrees, particularly 30 to 85 degrees.

As the resin coating band, there are many elastomers such as soft vinyl chloride resin, ethylene-vinyl acetate copolymer, styrene-butadiene block copolymer, thermoplastic elastomer such as polyurethane, as well as ethylene-propylene rubber, ethylene-propylene rubber, and ethylene-propylene rubber. Rubbers such as propylene-diene rubber, styrene-butadiene rubber, nitrile-butadiene rubber, polybutadiene, polyisoprene, butyl rubber may also be used. The adhesive strength (A) per unit width of the resin coating can be controlled within a certain range by, for example, adding a tackifier. Tackifiers include coumaron resin, phenol,
Terpene resins, petroleum hydrocarbon resins, rosin derivatives, etc. can be used. Furthermore, the strength T) per unit width of the resin coating can be controlled within a certain range by selecting the tensile strength and thickness of the resin coating band.

In the present invention, the resin coating band used is expressed by the following formula 2% (1
) In the formula, A is the adhesive strength per unit width (cm) between the resin coating band and the lid, T is the strength per unit width (0 layer) of the resin coating, and C is a constant (900). In the case of a resin coating that satisfies the following, it is necessary to prevent the resin coating from breaking while ensuring that the coating is fixed to the area to be opened and removed from the area around the end cap when opening the package. It is preferable because it can be carried out.

These resins are applied to the surface of the binding in the form of a solution, latex, plastisol, organosol, etc. In order to reliably fill the score, the viscosity of the coating liquid must be 40,000.
It is desirable to set it to less than cps.

The thickness of the resin coating is generally 0.00 on average in the width direction.
5 to 0.5 mm, particularly preferably 0.01 to 0.30 mm, and from the point of view of the protective effect, the outward protrusion dimension from score 8 should be 0.005 to 3 mm, especially 0.01 mm.
It is desirable that the thickness be in the range of 01 to 2■ layers.

(Example) The present invention will be further specifically explained using a first example.

Evaluations of Examples and Comparative Examples were performed as follows.

1. Condition of organic resin coating band 1-1. Coverage on score After obtaining an organic resin coating band by applying organic resin on the outer surface of the lid around the score, a score of 3 is obtained when the entire score length is completely covered, and a score of 3 is given when the entire score length is not covered. Those whose ratio to the score length was 99 to 95% were given a score of 2, and those whose ratio was less than 95% were given a score of 1.

1-2. Uniformity of the coating band The width of the organic resin coating band obtained in 1-1 was measured over the entire length,
(Minimum width of covering band) ÷ (maximum weight of covering band) is 1 to 0.7
Score 3 for the range 0. Score 2 for the range 0.89 to 0.50.
．． A range of less than 0.50 was evaluated as a score of 1.

2. Rust state of score section in actual can 2-1. Immediately after heat sterilization, the lid with the organic resin coating band was wrapped around the can body of a No. 3 tuna can filled with bonito seasoning using a conventional method, and after heat sterilization at 116°C for 90 minutes, the state of rust was determined by the score on the outside of the lid. When observed with a stereomicroscope, if there is no rust on the score part, a score of 3 is given, and if the ratio of rust to the score length is 99-95%, a score of 2 is given.
．． A sample with this ratio of less than 95% was given a score of 1.

2-2 The heat-sterilized cans obtained in 2-1 were stored at room temperature for one year, and then evaluated in the same manner as in 2-1.

3. Safety Open the lid provided with the organic resin coating band and observe the organic resin band on the cut end surface of the open piece with the naked eye. If the cut end surface is completely covered with the organic resin band, score 3. The ratio of the length of the uncoated cut end face to the total cut end face length is 99~
A score of 2 was given for 95%, and a score of 1 was given for a percentage of less than 95%.

Example 1 Epoxy was applied to both sides of a commercially available electrolytically chromic acid treated steel plate (thickness: 0.20 mm) in which the amount of metallic chromium was 100 g/@2 and the amount of chromium in the non-metallic chromium layer was 15 g/@2. A phenol-based paint was applied to a dry thickness of 571 m, and baked at 210°C for 10 minutes. This coated electrolytic chromic acid treated steel plate was cured to a diameter of 211 using a press, and then a sealing compound was applied to the curled part using a conventional method.
The score was processed to have a circular score with a residual thickness of 45 ILm.

Using a nozzle lining device, apply vinyl chloride plastisol compound (viscosity 2000 cp5) around the outer score of the lid obtained in this manner at a rotation speed of 800 RPM and a distance of about 1 layer between the nozzle tip and the lid. 60 shoes/
After coating the lid in a thick layer, it was heated at 150° C. for 2 minutes.

An aluminum alloy tab coated with an epoxy-phenol primer on both sides was adhered to the lid thus obtained using a nylon adhesive at 220°C. The inner surface of this lid is coated with epoxy-phenol paint to a thickness of 60 mm after drying.
It was spray-painted so as to give mg/lid and baked at 200° C. for 4 minutes.

Regarding the easy-to-open adhesive obtained in this way, the condition of the organic resin coating band, the rusting condition of the score part in the actual can, and the safety were evaluated. The results are shown in Table 1.

Examples 2, 3.4 In Examples 2.3 and 4, the thickness of the salt pea plastisol compound was 100 g/lid, 140 g/lid, and 140 g/lid, respectively.
An easy-to-open lid was manufactured in the same manner as in Example 1 except that the ratio was changed to 200+g/lid, and each evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 After performing score processing in the same manner as in Example 1, an aluminum alloy tab was joined to the lid using rivets in a conventional manner.

The distance between the nozzle tip and the lid obtained in this way is approximately 3cm.
A PVC-plastisol compound was applied, dried, and an epoxy-phenol paint was sprayed and baked in the same manner as in Example 1, except for changing to a sheet, and then various evaluations were performed. The results are shown in Table 1.

Comparative Examples 2.3 and 4 In Comparative Examples 2.3 and 4, the thickness of the PVC plastisol compound was 100 mg/lid and 140 IIg/
Each evaluation was performed in the same manner as Comparative Example 1 except that the lid was changed to a 200 mgl lid. The results are shown in Table 1.

Example 5 Phosphoric chromic acid treatment (chromium amount is 20011 g/dm2
) commercially available aluminum plate (Q, 25 m thick, 5
An epoxy-phenol paint was applied to both sides of the 052 material to a thickness of 5 pm after drying, and baked at 210°C for 10 minutes.

This coated aluminum plate was cured to a diameter of 211 using a press, and then a sealing compound was applied to the curled portion by a conventional method and dried. Next, add a diameter of 5mm to the outside of the lid.
Score processing was performed on a circle of 8 meals so that the score remaining thickness was 80 #Lm.

Using a spray gun, apply 60 mg of PVC-organosol (viscosity 150 cps) around the score area on the outer surface of the lid obtained in this way under the conditions that the rotation speed of the lid is 40 ORPM and the distance between the spray gun nozzle tip and the lid is about 11 layers. After coating the lid in a thick layer, it was heated at 150°C for 2 minutes.

An aluminum alloy tab coated with an epoxy-phenolic brimer on both sides was adhered to the lid thus obtained using a nylon adhesive at 220°C.

Spray coat the inner surface of this lid with epoxy-phenol paint to a thickness of 605 g/lid after drying.
Baking was performed at 0° C. for 4 minutes.

The easy-to-open binding thus obtained was subjected to the same evaluations as in Example 1. The results are shown in Table 1.

Examples 6, 7.8 In Examples 6, 7, and 8, the thickness of the PVC organosol was 100 mgl, 140 mg/M, and 20 D, respectively.
An easy-to-open lid was manufactured in the same manner as in Example 5 except that the lid was changed to rag/lid, and the same evaluations as in Example 5 were performed.

The results are shown in Table 1.

Comparative Example 5 In Comparative Example 5, score processing was performed in the same manner as in Example 5, and then an aluminum alloy tab was joined to the lid using a rivet using a conventional method.

PVC organosol was applied to the thus obtained lid in the same manner as in Example 5, except that the distance between the tip of the spray gun nozzle and the lid was changed to about 3 cm, dried, and then sprayed with epoxy-phenol paint. After painting and baking, various evaluations were performed. The results are shown in Table 1.

From Examples 1 to 8 and Comparative Examples 1 to 8, the method of joining the tabs after providing the organic resin coating band around the score part is more effective than the method of joining the tabs and then providing the organic resin coating band. It can be seen that not only an easy-to-open lid that is excellent in the condition of the band, the state of rust on the score portion, and safety when opening is obtained, but also excellent in high-speed productivity.

[Brief explanation of drawings]

FIG. 1 is a top view of the lid obtained in the first step of the present invention, and FIG. 2 is a sectional view of FIG. 1. 3 is an enlarged sectional view of the main part of FIG. 2, FIG. 4 is a top view of the lid obtained in the second step of the present invention, FIG. 5 is a side sectional view of FIG. 4, and FIG. FIG. 5 is an enlarged sectional view of the main parts of FIG. 5, FIG. 7 is a top view of the lid obtained in the third step of the present invention, FIG. 8 is a side sectional view of FIG. 7, and FIG. 9 is the main part of FIG. 8. An enlarged cross-sectional view. FIG. 10 is a diagram illustrating a stage in the middle of opening. l is attached, 2 is metal material, 3a is outer surface protection coating, 3b
is an inner surface protective coating film, 4 is a circumferential groove portion on the outer periphery, 5 is an annular rim portion, 6 is a panel portion, 7 is a sealing compound layer, 8
is the score, 9 is the part to be opened, 10 is the varnished core, 11 is the rim part or the entire step, 12 is the resin coating band for protecting the cut edge, 13 is the opening tab, 14 is the tip for stamping the score, 15 is a grip part (ring), 16 is a fulcrum part, 17 is a U
18 is a connection part, 19 is a thermoplastic resin adhesive layer, 20 is an outer periphery, 21 is a cut edge, and 22 is an outwardly projecting part.

Claims (1)

[Claims] (1) Forming the lid material into a lid and carving at least one score on the lid to define the part to be opened; and prior to fixing the opening tab, completely covering the score and A process of coating the score with a resin for protecting the cut edge of the score, which also serves as rust prevention, so as to straddle the score, and inserting an opening tab so that the tearing tip is positioned on or near the coated score. 1. A method for manufacturing an easily openable lid, comprising the step of adhesively fixing the lid to a portion to be opened.