JPS63115736A - Metallic bonding structure - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention uses a polyamide-based primer coated fully flexible material! The present invention relates to a metal bonded structure bonded using Ii young agent, and more particularly to a bonded structure having resistance to bond failure due to 1Mi bonding, especially beer bonding. In particular, the present invention relates to a bonded rXa structure in which a tear tab for shearing the bound score is fixed to the tllN via an adhesive.

(Prior art) Conventionally, easy-to-open M used for cans containing beverages such as cola, beer, and juice has been developed by using an opening section divided by scores (partial cutting lines). A widely used method is to form a rivet in the opening part, fix a tension tab with the rivet, and pull the tab so that the score is broken and the opening part is removed. There is.

However, with this easy-to-open lid, the inner coating of the four lids is easily damaged due to harsh processing such as riveting.
For applications such as edible canning, in which corrosive contents are filled and harsh treatments such as heat sterilization are performed, satisfactory results in terms of corrosion resistance cannot be obtained.This tendency is due to the following: The four easy-to-open lids made of aluminum are especially written by w.j. Furthermore, contents with a high salt concentration cause pitting corrosion, and there is a problem of leakage of contents from through holes and contamination by bacteria.

Japanese Utility Model Publication No. 51-524 proposes an easy-to-open 4-lid in which an opening piece is adhesively fixed to an opening section defined by scores. Polyamides are also known to be excellent hot melt adhesives for bonding metals together.

(Problems to be Solved by the Invention) In this type of easy-to-open lid, by lifting the grip part of the opening piece upward, the adhesive part becomes a fulcrum, and the opening piece (
Shearing of the score is started by pushing the tip of the tab) into the score, and then shearing across the entire score is performed by pulling the tab, but in this case, the force necessary to tear the score is applied to the adhesive part The problem is that the bond acts as a moment and is likely to cause damage to the bonded portion.

In addition, the method of opening an easy-open lid varies depending on the purchaser of the can; for example, when pulling the tab without lifting the tab to a position almost perpendicular to the lid, A relatively large moment S acts on the adhesive fulcrum between the tab and the lid, making it easy for the adhesive fulcrum to break. Furthermore, if the tab is not pulled correctly in the tab direction, a moment will still act on the adhesive fulcrum, making it easy for the adhesive fulcrum to break.

Polyamide-based adhesives have large hydrogen bonds between molecular chains and particularly high cohesive fracture force among component polymers, and are also suitable for use in protective coatings, etc. applied to protect the metal material for the lid. Therefore, even when the aforementioned easy-to-open lid is opened, there is almost no risk that the polyamide adhesive layer at the adhesive fulcrum or the joint between the adhesive layer and the paint film will be destroyed. However, instead, it is recognized that peeling or destruction often occurs at the adhesion interface between the paint film and the metal material.The reason for this is that although the peeling force between the full flexure and the paint film is quite large,
Since almost no deformation (elongation) occurs between the two, it is presumed that stress concentration occurs in this part, leading to fracture.

Therefore, the present invention uses polyamide-based primer coated metal materials! In a metal bonded structure formed by bonding with a TCI agent, by allowing a certain degree of partial failure in the adhesive layer, failure between the primer and the metal material is prevented, thereby reducing overall adhesive failure, especially moment An object of the present invention is to provide an adhesive structure that prevents adhesive failure under conditions where

(Means for Solving the Problems) The present invention provides a metal adhesive structure in which primer-coated metal materials are bonded to each other using a polyamide adhesive. The number of carbon atoms is 6.
a linear aliphatic polyamide within the range of 1 to 15;
B) At least one group selected from the group consisting of carboxylic acid, carboxylic anhydride, carboxylate, carboxylic acid amide, and carboxylic ester bonded to the polymer chain =
and an olefin copolymer containing co groups at a concentration of 10 to 400 mmol/100 g of polymer, A:B=9
Using an adhesive layer containing a weight ratio of 4:6 to 85:35 in which polyamide (A) is present as a continuous phase and olefin copolymer (B) as a dispersed particle phase, and niboxy resin and phenol as a primer. 9 with resin
It is characterized by using a curable coating film containing an ffi ratio of 5:5 to 30:70.

(Function) In FIG. 1, which shows an enlarged cross-sectional structure of the adhesive structure of the present 9i, this adhesive structure shows the aforementioned adhesive fulcrum of the four lids and the opening piece tab in an enlarged manner, With the outside of the can facing up,
The inside of the can is shown facing down.

An adhesive primer layer 2 is provided on the outer surface of the metal element 21 lid l, and a protective coating film 3 is provided on the inner surface, while an adhesive primer layer 5 is provided on the inner surface of the metal opening tab 4.
Further, a protective coating film 6 is provided on the outer surface. Tj! Ir
11 and the opening tab 4 are joined by an adhesive layer 7 via adhesive primer layers 2 and 5 applied to their surfaces.

According to the present invention, as the adhesive primer layers 2 and 5, epoxy resin and phenolic resin are used in a ratio of 95=5 to 30:
A curable coating film was used in which the adhesive layer 7 contained a linear aliphatic polyamide and an olefin copolymer in a weight ratio of 94=6 to 65:35. In addition, a layer of a composition is used in which the polyamide is the continuous phase and the olefin copolymer is the dispersed phase.

FIG. 2 of the accompanying drawings is an electronic W4 micrograph (magnification: 10,000 times) showing the cross-sectional structure of the adhesive layer used in the present invention.
In this photograph, the polyamide continuous phase appears black, and the olefin copolymer dispersed phase appears white.

In the present invention, when a VC adhesive layer having a structure in which polyamide is a continuous phase and an olefin copolymer is a dispersed phase is used, peeling failure between the brimer coating film and the metal material is suppressed in an adhesive peeling test. This is based on the knowledge that the overall toughness against adhesive failure is improved.

FIG. 3 of the attached drawings shows that the epoxy-phenolic primer of Example 1, which will be described later, is used as the primer coating.
In addition, as an adhesive, nylon 6.10 alone was used (sample A), and nylon 6.10 and ethylene vinyl acetate copolymer (copolymerization ratio 90/10.MI5) were used at 85:1.
5 to form a dispersed structure as shown in Figure 2 (Sample B), and nylon 6,1O and the above ethylene vinyl acetate copolymer were blended at the same weight ratio, but uniformly・Using the dispersed tissue (sample C),
After forming the adhesive fulcrum for the easy-to-open lid, apply and bake the lid inner surface repair paint, and then perform hot water treatment equivalent to retort sterilization assuming a commercial can, and then apply the adhesive fulcrum at a pulling speed of 200.
The results show the peeling force (Kg) and displacement ffl:(Cffi) in the 90 degree direction at /sec. In FIG. 3, the ultimate peel force of the rise is related to the initial opening force of the lid, and the fine value of the curve corresponds to the 90 degree peel work layer.

: From the results shown in Figure 53, the following can be seen. That is.

When nylon alone is used as the adhesive (sample A), the ultimate peeling force is extremely large, but it is clear that destruction occurs within a small amount of displacement. When we actually observe Sample A, we find that the failure is predominant at the adhesive interface between the primer coating and the metal. Therefore, in the case of Sample A, the location where stress is concentrated is at the interface between the primer coating and the metal. , it is shown that the adhesive fulcrum is still unsatisfactory in terms of toughness (90 degree peeling work). In addition, in the case of an adhesive layer (sample C) in which nylon and olefin copolymer are uniformly dispersed, although the amount of displacement is large, the final pulling force is quite low, and the adhesive layer has a large amount of displacement. It will be understood that breakage easily occurs. On the other hand, when an adhesive layer (sample B) in which polyamide is a continuous phase and an olefin copolymer is a dispersed phase is used according to the present invention, the ultimate peeling While maintaining the force at a relatively large level, it is possible to achieve a large amount of displacement at this level, and the 90 degree peeling work, that is, the toughness of the adhesive fulcrum, can be increased compared to Samples A and C. It turns out that it is possible.

This seems to indicate the following regarding the failure of the adhesive fulcrum: That is, the adhesive failure between the primer coating and the metal occurs with a force greater than the ultimate peeling force of Sample A, but in the adhesive structure of the present invention, as shown by curve B in FIG. The action only partially destroys the polyamide continuous phase in the adhesive layer, preventing breakdown between the primer coating and the metal, and still preventing the breakdown of the adhesive layer. Due to the increasing workload,
On the contrary, the adhesive fulcrum is prevented from being destroyed. In order to effectively use polyamide with a large cohesive force as a stress carrier, a heterogeneous distribution structure as shown in Figure 2 is essential.In a uniformly distributed structure like Sample C, the strength of the Pi adhesive layer itself is indispensable. This will lead to a decline.

In the polyamide used in the present invention, the average number of carbon atoms in the main chain of one amide group is related to the strength of intermolecular hydrogen bond,
In addition, if the average number of main chain carbon atoms per amide group is smaller than 6.1, which has a significant effect on the size of cohesive force, hardness, or affinity for water, the melting point becomes too high. Possible bonding temperatures tend to become too high, making bonding operations difficult, causing inconveniences such as scorching of the bonding primer and protective coating, and making it difficult to control cooling after bonding, resulting in the formation of crystals, which will be discussed later. It tends to be difficult to control the degree of
This polyamide is also extremely sensitive to wood,
The mechanical properties vary greatly depending on the moisture content.Furthermore, the moisture content tends to cause defects such as foaming in the adhesive, and the average number of carbon atoms in the main chain per amide group is 15.
．． If it exceeds 0, the cohesive force of the polyamide itself tends to decrease, resulting in a decrease in heat resistance, resulting in a decrease in adhesion to the score area when the correction paint is baked or during retort sterilization, and in severe cases, the adhesive fulcrum point Even l deviations occur. Furthermore, the adhesion to the primer coating also decreases.

It is also important that the olefin copolymer used in the present invention has a carboxylic acid, carboxylic anhydride, carboxylate, carboxylic acid amide, or carboxylic ester group bonded to one polymer chain; Olefin copolymers that do not contain polyamides lack dispersibility in polyamides, and even if they are dispersed, the bonding at one grain boundary is insufficient and the adhesive layer tends to become brittle. The concentration of the group is 10 to 400 mmol/10Qg
, especially 15 to 300 mmol/Zo.

It is also important that the concentration is within the above range; if this concentration is lower than the above range, the above-mentioned drawbacks are likely to occur; if it is higher than the above range, dispersion in the polyamide will become difficult. There is a tendency for thermal decomposition and foaming to occur during kneading.

Polyamide (A) and olefin copolymer (B) A:
It is also important to use a weight ratio of B=94:6 to 65:35, especially 91:9 to 70:30, and if the amount of olefin copolymer is less than the above range, polyamide may be used alone. The same drawbacks as in the case where the amount is above the above range appear, and when the amount is more than the above range, the mechanical strength of the adhesive layer tends to decrease, and the adhesive force with the primer layer also tends to decrease.

In the adhesive layer used in the present invention, the median minor axis of the dispersed particles and phase (olefin copolymer) is 0.05 to 10.
JL, especially 0.5 to 81L, is desirable for the purpose of the present invention.In the adhesive layer used in the present invention, since it has the above-mentioned dispersion M1m, the olefin copolymer phase and polyamide phase are Since the contact interface is extremely large, the strain that tends to remain in the adhesive layer during the adhesive cycle of hot melting and cooling solidification is easily summed up at the contact interface between the two M, and as a result, over time A bonded structure without deterioration in adhesive strength can be obtained.

The primer coating film having the above composition used in the present invention has particularly excellent adhesion to metals, exhibits excellent adhesion to the polyamide-olefin copolymer blend layer mentioned above, and is resistant to metals. It is also excellent in that it imparts corrosive properties. If the epoxy resin component exceeds the above range, interfacial peeling with the adhesive will easily occur, while if the phenol resin component exceeds the above range, interfacial peeling with the metal will tend to occur, and the primer coating IF2 will become brittle. There are also trends.

(Operations and Effects of the Invention) According to the present invention, when bonding primer-coated metal materials using a polyamide adhesive, stress concentration occurs at the adhesion interface between the primer coating film and the metal material, and this portion is prevented from being destroyed. Circulation is to prevent this and increase the toughness of the entire joint against adhesive failure. By applying this adhesive structure to the adhesive fulcrum between the wrapper and the opening tab, an adhesive fulcrum with excellent peeling resistance is provided even when a moment is applied, and the lid material becomes 'I! Although it is made of a rigid metal material that is used to fasten and secure it to the I-shell, it effectively prevents the joint fulcrum from breaking when opening, and has the advantage that it can be opened stably even after a long period of time. achieved.

(Description of Preferred Embodiments of the Invention) Structure of the Lid As shown in FIGS. 1, 4 and 5, the easy-to-open wrapper of the present invention is made of a rigid metal material 1 provided with a primer coating 2.

This lid member 1 includes a circumferential groove portion 8 on the outer periphery and a panel portion 10 connected to the groove portion via an annular rim portion 9. 1!
The first portion 8 is provided with a layer 11 of sealing compound which is sealingly engaged with the can body flange (not shown) during double seaming. Inside the annular rim portion 9 there is a portion 13 to be opened, which is defined by a score 12 . This opening portion 13 may substantially coincide with most of the panel portion 10, or a portion of the panel portion 10 may be the opening portion. As shown in , it is provided so as to reach the middle of the metal material 1 in the thickness direction, and the shearing is easily performed when the package is opened by a mechanism described in detail below.

According to the invention, this opening portion 13 is also provided with an opening tab 4 in a particular arrangement as described below. This opening tab 4 has a score tearing tip 14 at one end, a gripping part (ring) 15 at the other end, and a fulcrum part 16 located between these parts and joined to the lid. In this embodiment, the fulcrum portion 16 has a generally U-shaped cut 17 in the tab between the tip 14 and the ring 15.
The connecting portion 18 is provided between the tip 14 and the tip 14, and is formed into a tongue shape. Opening tab 4
The tearing tip 14 is placed at the tongue-shaped fulcrum portion 16 so that its position almost coincides with the score 12 of the lid.
It is thermally bonded to the opening portion 13 of the lid via the polyamide adhesive layer 7.

In various aspects of the present invention, when the ring 15 of the opening tab 4 is picked up with a finger and lifted upward, this force is applied to the fulcrum part 1.
6 to the tearing tip 14 as a downward force, and at the same time a downward tearing force is applied to the score 12, the adhesive layer 7 between the fulcrum part 16 and the opening part 13 is peeled off. According to the present invention, the above-mentioned specific polyamide-olefin copolymer blend adhesive is used as the adhesive layer 7, so that it can withstand the above-mentioned peeling force. Then, by pulling the opening tab 4 at an angle of approximately 90 degrees with respect to Ml, the score 12 is sheared from the position where the cut was made.

Metal materials for the Moxibustion J Mugi cover include light metal plates such as aluminum and various surface-treated steel plates such as zinc, tin, etc. on the surface of steel plates.
Any metal material can be used that is plated with chromium, aluminum, etc., or has a chemical conversion treatment film of chromic acid, phosphoric acid, etc. formed on the surface, and has pressure deformation resistance and rigidity that can withstand seaming. . The thickness of the material is generally 0.10 to 0.40 mm.

In particular, it is desirable that the opening tab is within the range of 0.12 to 0.35 mm.
In particular aluminum is used.

The lid material of the present invention is suitable for metal materials that are difficult to rivet, such as chromate-surface-treated steel sheets, especially electrolytic chromate-treated steel sheets, chromate-treated nickel-plated steel sheets, chromate-treated films, tin alloy-plated steel sheets, chromate-treated films and nickel alloy-plated steel sheets. It is suitably applied to steel plates, chromate treated film/tin/nickel alloy plated steel plates, and chromate treated aluminum plated steel plates.

Electrochromic acid treated steel sheets consist of a metallic chromium layer on a cold rolled steel substrate and a non-metallic chromium layer thereon. The thickness of the metallic chromium layer is determined by the balance between corrosion resistance and workability, and the amount is preferably 30 to 300 + * g/m2, particularly 50 to 250 mg/mz (1) aVJJ. The thickness of the nonmetallic chromium layer is related to coating adhesion and close peel strength, and is expressed as a chromium amount of 4 to 40 II g per layer 2, especially 7 to 30 m.
It is desirable that it be in the range of g/ls2.

Primer The primer coating film used in the present invention is used for the purpose of promoting adhesion and protecting the underlying metal, and contains a phenol resin and an epoxy resin in the above-mentioned quantitative ratio. As the phenol resin, a resol type phenol aldehyde resin obtained by condensing various phenols and formaldehyde in the presence of a salt-based catalyst is used. Phenols include trifunctional phenols represented by carbolic acid, difunctional phenols represented by p-cresol, and bisphenol A.
Polynuclear phenols represented by polynuclear phenols are used alone or in combination of two or more types, but a phenol resin particularly suitable for the purpose of the present invention is represented by the following formula 1 formula %, where M2 is contained in the phenol aldehyde resin. M3 is the number of moles of trifunctional monohydric phenol in 100 g of total phenol components, M4 is the number of moles of trifunctional monohydric phenol in 100 g of total phenol components, - The functional index (1,F,) defined by the number of moles of 1.5 to 2.5
, especially in the range of 1.8 to 2.8. In addition, the number of methylol groups per phenol nucleus is 0 on average.
．． 05 to 0.40, particularly 0.07 to 0.30, and the number average molecular weight is generally 200 to 80.
0, particularly in the range of 230 to 600.

As an epoxy resin, the epoxy equivalent obtained by condensation of bisphenol A and epihalohydrin is 600 to 6.
000, especially epoxy resins in the range of 900 to 4000 are preferably used.

Epoxy resins and phenolic resins are used in the form of a mixture or in a precondensed form to paint metal materials, and after being applied to the metal materials, they are baked at 140 to 280 degrees Celsius for 1 to 20 minutes. It is best used for post-adhesion.

The thickness of the primer coating is not particularly limited as long as the above-mentioned purpose is achieved, but generally speaking, it is between 0.2 and 3.
0 Bm, preferably in the range of 1 to 20 pm.

In the present invention, the first condition is to use a polyamide in which the average main chain carbon number of the amide group 14i is in the range of 8.1 to 15.0, particularly 7.0 to 14.0. The polyamides may be homopolyamides, copolyamides or blends thereof having ω-aminocarboxylate and/or diamine-dicarboxylic acid salts as starting monomer components; examples of suitable polyamides are given in Table A below. It is as follows.

Of course, in the case of copolyamide or blended polyamide compositions, the total! There is no problem in containing ω-aminocaproic acid units, hexamethylene adipamide units, etc., provided that the I component satisfies the above-mentioned restrictions.

The polyamide used in the present invention contains 100cc of 98% sulfuric acid.
The specific viscosity (ηγ) measured at 20°C at a concentration of 1 gram of polyamide is preferably in the range of 1.8 to 3.5. The mechanical properties are poor, and the joint strength is not sufficient. Further, polyamides with specific viscosity values higher than the range of the present invention are not preferred because the melt viscosity of the adhesive becomes too high during melt adhesion, and adhesion is required at a temperature considerably higher than the melting point.

Part A: The olefin copolymer used in the present invention contains groups of carboxylic acid, carboxylic anhydride, carboxylic acid salt, carboxylic acid 7amide, or carboxylic acid ester that are frequently bonded to each other. Such olefin copolymers can be obtained by copolymerizing an ethylenically unsaturated monolayer containing the above groups with olefins, or by modifying polyolefins by means such as graft polymerization or block copolymerization. It will be done.

Suitable examples of the carboxylic acid derivative group-containing ethylenically unsaturated monomers mentioned above are as follows.

i) Carboxylic acid or carboxylic acid anhydride.

Acrylic acid, methacrylic acid, fumaric acid, maleic anhydride, itaconic anhydride, crotonic acid, tetrahydrophthalic anhydride.

ii) Carboxylic acid amide Acrylamide, methacrylamide, maleimide.

iii) Carboxylic acid esters Vinyl esters such as vinyl acetate and vinyl propionate, ethyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 3-hydroxypropyl (meth)acrylate, N-ethylaminoethyl (meth) (Meth)acrylates such as acrylate.

Suitable examples of olefin copolymers are as follows.

Ethylene random copolymers such as ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, and ethylene-ethyl acrylate copolymer.

Ionically crosslinked olefin copolymers, such as ethylene or propylene and acrylic acid or methacrylic acid, are copolymerized with these ester monomers if necessary, and alkali metal ions such as sodium and potassium, alkaline earth metal ions such as magnesium, etc. A copolymer formed by ionic crosslinking with , zinc ions, organic cations, etc.

Polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-
A copolymer made by grafting maleic anhydride, acrylic acid, methacrylic acid, (meth)acrylate, (meth)acrylamide, etc. onto a backbone polymer such as vinyl acetate copolymer.

Of course, these copolymers should contain CO groups based on carboxylic acid or derivatives thereof in the concentrations mentioned above, i.e. from 10 to 400 mmol per 100 grams of copolymer. Of course, the above-mentioned copolymer may have the above-mentioned concentration as a whole; for example, it may be a blend of two or more olefin copolymers having different CO group concentrations.

It may also be a blend of an unmodified olefin polymer and a modified olefin copolymer.

The olefin copolymer used should have a molecular weight sufficient to form a film, have a melting point in the range of 40 to 200°C, especially 60 to 180°C, and have a melt flow rate (MI) of 0. 5 to 300, especially 0
．． It is advantageous for the dispersion structure of the present invention to be within the range of 7 to 150.

Although it is essential to use the polyamide and olefin copolymer in the above-mentioned ratio in order to obtain the dispersion structure defined in the present invention, this alone is not sufficient, and the degree of melt cross-contamination of both resins is also essential. You need 1 piece of 2g. The degree of crosstalk varies depending on the melting point and functional group concentration of the resin.
Although it cannot be generally specified, it is generally desirable to dry blend the two resins and then knead them using a metering type screw and form them into a film. Unless the length is made extremely short, the dispersion of both resins becomes homogeneous and it is difficult to obtain the dispersed structure of the present invention.

This adhesive contains antioxidants, heat stabilizers, ultraviolet absorbers, viscosity modifiers, plasticizers, core materials, = a fine particles, fillers, organic lubricants, pigments, synthetic rubber latex particles, etc. for its adhesive performance. 20% by weight of the entire resin composition unless it significantly impairs
It can be added as an additive within a range not exceeding .

1 construction 1 shame Easy opening of the present invention! When manufacturing lids.

First, on at least one side of the metal material mentioned above, a primer coating is applied in the form of an organic solvent solution, an aqueous dispersion, or an aqueous solution by means such as spray coating, roller coating, dip coating, electrostatic coating, electrophoretic coating, etc., A coating film is formed by drying or baking. In this case, it is also possible to laminate a thermoplastic resin film on the side different from the side on which the adhesion fulcrum is formed using an adhesive, if necessary.

This painted or painted laminate plate is punched out to a predetermined size of 1 m, and then press-formed into a predetermined shape.Score processing is performed at the same time or in a separate process. The thickness is 1/8 to 1/2 of the base plate thickness, and the absolute thickness is 0.2 to 0.
．． It is desirable to have an 8-layer set, especially one in the range of 0.3 to 0.8 layers.

Prior to or after this scoring process, a sealing compound composition made of a synthetic rubber latex such as styrene-butadiene rubber latex, a tackifier, and a filler is applied to the circumferential groove of the binding and dried. and form a compound layer.

A layer of the above-mentioned blend adhesive may be provided on the fulcrum part of the separately manufactured opening tab, or a fin of blend adhesive may be provided on the part where the opening tab of the attachment is to be provided.
establish. Of course, it is also possible to do both. The adhesive layer can be formed by any method other than applying an adhesive film cut to a predetermined size, such as applying the adhesive in the form of powder, melt, suspension, or solution. can.

The thickness of the adhesive resin is suitably in the range from 3 to 150 lumens, in particular from 10 to 1100 mm.

Next, the opening tab is positioned on the wrapping, and the thermoplastic resin placed between the fulcrum part of the tab and the W1 lid is melted and then cooled and solidified to complete the adhesion between the two. In addition, prior to this, the vicinity of the score may be lined with a resin such as rubber or plastisol in order to prevent injuries when the lid is opened.

In the case of edible canning, it is desirable to submerge the entire circumference close to the original rim, as shown in the attached drawing, in a so-called full oven format. It is also possible to provide a part of the shape with an arbitrary shape such as a raindrop shape or a semicircular shape. In addition, in order to repair damage to the covering material during scoring on the inner surface of the lid, paint is further applied and baked as necessary.

The adhesive structure of the present invention is most effective as an approach fulcrum for the above-mentioned easy-to-open lid, but this advantage can be applied to other adhesive applications, for example, when a complex directional component force such as a peeling force is applied to the adhesive surface. It should be understood that the same effect can be achieved even when used for bonding between metal materials.

The following examples specifically explain the effects of the present invention. In each example, the following adhesive properties are described for metal bonded structures made of materials for each test number. Tie properties (I) and adhesion to a lid as an application example (II) were evaluated.

Adhesive test plate thickness 0.22I1m, amount of non-metallic chromium on the surface 15B/m
2. Epoxy-phenol paint (the exact ratio and composition of epoxy resin and phenol resin are as described in each example below) on both sides of a regular tin-free steel (TFS) plate containing 100 mg/■2 of metallic chromium. (slightly different) was applied to a thickness of 5 gm after baking, and heated at 210°C for 1
Baking was performed for 0 minutes.

A test piece with a width of 5 II 11 and a length of 10 cm was cut out from this painted plate, each adhesive film with a width of 7 H was sandwiched between the two test pieces, and then bonded using high frequency heating. The bonding temperature is the melting point of each adhesive +30 for the entire bonding surface.
The goal was to achieve a temperature of ℃. Some of these adhesive pieces were heated in an oven for 4 minutes at 20°C below the melting point of each adhesive in order to investigate the effect of post-heating applied during baking and curing of paint when repairing damage to the score processed area on lids, etc. A portion was treated with hot water equivalent to retort sterilization at 116° C. for 90 minutes, and a portion was placed in water at 90° C. for one week.

To evaluate the adhesion, a T-peel test was performed on five test pieces each after heating in an oven at the initial stage of adhesion, after retorting, and after aging in hot water at 90°C. For the T peel test, an Instron type tensile testing machine was used, and the tensile speed was 200 m.
m/sin was measured at room temperature, and the arithmetic mean value of the average values of each measurement value was used as the result.

■ Lid adhesion test As a specific application example of the metal adhesive structure of the present invention, Fig. 4
．． As shown in 5! An adhesive structure in which a tear tab for shearing the lid score was fixed to the wrapper via an adhesive was tested for adhesive performance. The lid for this purpose was created as follows.

In other words, the same epoxy used in the previous test was applied to both sides of a regular tin-free steel (TFS) plate with a thickness of 0.20+sm, a surface non-metallic chromium content of 15g/m2, and a metal chromium of 100+g/m2.・Apply phenolic paint to a thickness of 5 gm after baking.

Baking was performed at 210°C for 10 minutes. This painted TFS plate was formed into a lid for diameter 211 using a press, and then a sealing compound was applied to the curled part by a conventional method and dried. Score processing was performed so that the steel plate thickness was 0.23. On the other hand, an aluminum coil with a thickness of 0.48 (9508
2) Apply epoxy phenol paint (the weight ratio of epoxy resin and phenol aldehyde resin is 75) to the adhesive side of the material.
= 25 (using bisphenol A as the raw material for phenol aldehyde resin) and epoxy area paint on the opposite side, each of which was kneaded into a coil to a thickness of 5 gm after baking, and then slit into a width of 30 m. On the other hand, a thickness of 45 to 50 g consisting of the composition shown in each test behavior below.
A microslit film having a width of 81 layers was laminated by high-frequency induction heating and then press-molded into a tab having the shape shown in FIGS. 4 and 5. The tabs prepared in this way are heated at least 30°C higher than the melting point of each of the 16 adhesives using high-frequency heating, so that the distance from the score to the adhesive fulcrum is 6 feet. I glued it. In this case, the width of the adhesive layer at the adhesive fulcrum was approximately 71 m, and the area of the adhesive portion was approximately 40 m+*2.

Next, after each tab was glued, an epoxy/phenol paint was applied to the scored parts of the inner and outer surfaces of the lid, and after baking in an oven for 4 minutes at a temperature of -20°C, the melting point of each adhesive, the following 1. The cavitation strength and lid opening ability described in Section 2 were evaluated.

1. Turbid strength After adhering the tab under predetermined bonding conditions, baking in a predetermined oven, and further performing retort sterilization equivalent to heat sterilization, the peel strength of this lid was measured by the following method. In other words, after lifting the tab and performing the initial opening of the score part and raising the tab vertically to the lid panel surface, place the tab ring perpendicular to the lid panel surface so that the adhesive part is at a 90° angle. A tensile test was conducted. The tensile test was carried out using an Instron type tensile tester at a tensile speed of 200 mm/sin at room temperature to evaluate the initial strength and peeling work. Peeling work was determined by integrating the area within the peeling strength curve on the chart using an automatic integrator and converting the result to 1 cm 2 of adhesive area. Each sample was measured five times, and the arithmetic mean value of these measurements was taken as the measured value.

2. Openability of the lid: ■ Immediately after adhesion; ■ After applying correction paint to the inside and outside of the lid and baking in the specified oven.
Furthermore, after double-sealing this lid to the 211-diameter flange can, filling the contents with dressing tuna, and sealing the flat lid, retort sterilization was performed for 90 minutes at 116°C. Twenty panelists were asked to open 5 cans each after a period of 10 months, and a total of 100 cans were opened. As a result, the number of cases in which the tab could not be opened in the middle of opening due to detachment is shown in four cases, and the number in parentheses indicates the number of cases in which the initial opening could not be completed among these opening defects.

Example 1 Each adhesive film is shown in Table 1! A composition consisting of 1 composition and a blend ratio was created. During film formation, Itll-1
, 1-3, the resin chips of both components were dry blended in advance, and in Nb1-4, the resin chips of the blue component were blended in advance.
After being kneaded into pellets using a axial extruder, each mixture was kneaded and formed into a film using an extruder equipped with a metering type screw. Further, in No. 1-5, film formation was carried out under the conditions that the melt-kneading temperature was lowered by 20°C than the standard temperature and the discharge rate was also 100% faster.

The dispersion structure of the cross section of these films was observed using a transmission electron microscope using an ultrathin section method. In order to capture a clearer dispersed structure, the phosphotungstic acid staining method was also used. 0inA is a structure in which the granular phase of polyolefin is dispersed in a continuous nylon resin phase, and A is a structure in which the dispersed structure is mostly dispersed. A homogeneous structure that is rarely observed, 0 and A, indicates a structure in which both the polyolefin phase and the nylon resin phase are continuous phases, and the presence of the polyolefin granular phase is unclear.

In evaluating the performance of these 16 adhesives, we used epoxy resin and phenol formaldehyde resin as primers.
Using a phenol formaldehyde resin with an f1M ratio of 85:15 and made from bisphenol A and p-cresol as raw materials, the test was conducted after obtaining a painted board for adhesion testing and a worn painted board according to the method described above. did.

The evaluation results are summarized in Table 1, and according to this, when the adhesive is made only of nylon resin, even if good initial strength or good strength is obtained after heating in an oven, the adhesive strength after retorting or aging in hot water There was a significant decrease in the strength of (
(Not-2, 1-3), and even when polyolefin is contained but no dispersed structure is formed, a similar decrease in strength is noticeable (Not-4) Furthermore, the dispersed structure of the polyolefin phase is disturbed, resulting in granular dispersion. In the case of non-structures, the strength generally showed a tendency to be low. These differences in adhesion correspond well to the peel strength and opening properties of the lid.
With Nb1-2.1-4, opening failure occurred in the actual can test, and Nb1-2.
With o1-5, opening failure occurred even in the initial stage of adhesion, and N
The difference in performance between b1-1 and the present invention was obvious.

Example 2 Nylon 610 was used as the polyamide resin component of the adhesive, and ionomer resin (ethylene acrylic acid copolymer total flex salt, −〇 = 0 group concentration 155 millimorph 100 g polymer, MI = 0.7) was used as the polyamide resin component of the adhesive. 1 table 2
With the blend ratio shown in Example 1 above. A film was produced in the same manner as in the case of N01-1.

The dispersion structure changes when the content of ionomer resin is low (No.
2-1) The granular dispersion structure was unclear and showed a homogeneous structure, whereas when the content was high (Nb2-8.2-9), the polyolefin phase also showed a tendency to become a continuous phase.

In evaluating the performance of these adhesives, we used epoxy resin and phenol formaldehyde resin as primers.
1ffi ratio is 80:20. Tests were conducted according to the method described above using a phenol formaldehyde resin made from bisphenol A and m-cresol.

The evaluation results are listed in Table 2, and when the content of the ionomer resin is low, the tendency is similar to that of the case of only nylon resin in Example 1, and the adhesion after retorting or aging in hot water is still poor. It's not enough.

Even in actual can tests with lids, opening defects may occur.

On the other hand, when the content of ionomer resin increases, the initial adhesive strength and especially the approach strength after open heating tend to decrease, resulting in a decrease in adhesiveness due to a decrease in the heat resistance or hot water resistance of the adhesive itself, and thus The ability to open the lid was also significantly impaired.

Example 3 For adhesive compositions in which the polyamide resin component has a different unit amide group dust average main chain carbon number, the polyolefin component maleic anhydride modified polypropylene c-c=o
xc degree 230 mmol/long ball combination, MI=3.5
) and their blend ratio was fixed at 80:20, and the relationship between the unit amide Oshima sumo unit master button size prime number and adhesiveness was investigated. The adhesive film was formed using the component chips shown in Table 3 in the same manner as in Example 1, Not-1.

In each case, the dispersed structure was such that a granular phase of polyolefin resin was dispersed in a continuous phase of polyamide resin.

Regarding the property IF '4 value of these adhesives, the weight ratio of epoxy resin and phenol formaldehyde resin as a brimer is 75:25. A phenol formaldehyde resin made from bisphenol A and 0-cresol was used, and a coated board was prepared and tested according to the method described above.

The evaluation results are listed in Table 3, and the unit amide 2! When nylon 6, which has an average main chain carbon number of 6, is used, only low adhesive strength is obtained, and interfacial delamination between the brimer and the plate tends to be dominant, and the opening of the lid is also poor. Even if an initial opening was made to some extent, there were many cases where the tab came off when the score part was sheared, resulting in failure to open (NO3-1)
In addition, even when nylon 66 is copolymerized with nylon 6, although the adhesion property is slightly improved, no improvement effect is observed, and the adhesion property between the brimer and the board decreases due to oven heating or retort treatment, etc. On the other hand, a blend of nylon 12 and dimer acid polyamide with an average main chain carbon number of 15 or more (16.5) per amide group was used. When used as a component, the heat resistance and hot water resistance of the adhesive itself are insufficient, resulting in a noticeable decrease in adhesive properties during oven heating, retort processing, etc., and also due to a decrease in the cohesive force of the adhesive itself. However, since a sufficiently high initial peel strength was not obtained in the lid, initial opening at the time of opening tended to be extremely difficult (No. 3-8).

Example 4 Nylon 1 was used as the polyamide resin component in the adhesive composition.
2 and using various polyolefin resin components with different carbonyl group concentrations, the relationship between the carbonyl group concentration of the polyolefin resin and the dispersed structure and the relationship between this and adhesiveness were investigated. No4-2~4-4
Now, in Nos. 4-5 to 4-9, the raw resin of No. 4-1 has a different grafting rate with maleic anhydride.
Metal salt resins of ethylene-methacrylic acid copolymers with varying copolymerization ratios were used as polyolefin resin components. In addition, for NO4-1 to 4 to 4, MI=30 to 80. N
For o4-5 to 4-9-t', those having an MI of 0.7 to 2.5 were used. From these resins, a blend ratio of 85:
15, Example 1. An adhesive film was obtained in the same manner as in the case of No. 1-1.

Except for Nos. 4-9, in which a homogeneous structure was dominant, the polyolefin resin phase generally showed a structure dispersed in the polyamide resin phase, but when low-density polyethylene with a carbonyl group concentration of almost zero was used ( Nb4-1),
It was found that the polyolefin resin had to have a certain concentration or more of carbonyl groups in order to obtain a good granular dispersion structure with significant blocking of the polyolefin phase and almost no Pro7 King. Furthermore, when the carbonyl group concentration of the polyolefin resin becomes extremely high, it tends to form a homogeneous phase with the polyamide resin, and foaming due to the decomposition of the resin increases during film formation, resulting in a decrease in film formability (Work 4-9). )
.

In evaluating the performance of these adhesives, the weight ratio of epoxy resin and phenol formaldehyde resin was 80:20 as a primer. p-cresol as phenol formaldehyde resin! A coated plate was prepared and tested using a phosphoric acid chromic acid treated aluminum plate (5082 material) with a thickness of 0.35 mm as the plate material, unlike the method described above.

The evaluation results are listed in Table 4, and the difference in the dispersion structure of the polyolefin resin phase is directly reflected in the adhesiveness, and when the degree of blocking of the polyolefin resin is large, the cohesive force of the adhesive film decreases, resulting in high adhesive strength. Regarding the opening property of 1M, it becomes difficult to obtain the opening property of 1M due to the decrease in peel strength, and there is a tendency for tab misalignment and tab detachment to occur frequently. On the other hand, when the carbonyl group concentration of the polyolefin resin increased and a homogeneous phase was formed with the polyamide resin, the hot water resistance of the adhesive tended to decrease.

Example 5 Nylon 610 and 8 of ethylene vinyl acetate copolymer (copolymerization ratio 9515, MI = 21) as +J127 agent
A film made of a blend composition of 5:15 and produced in the same manner as in the previous section was used. This adhesive film had a typical polyolefin particulate dispersion structure.

As primers, primers were used in which the weight ratios of epoxy resin and phenol formaldehyde resin were varied as shown in Table 5. Here, a phenol formaldehyde resin made from bisphenol A and p-cresol is used, and in case 5-1.5-2 where the content of phenol formaldehyde resin is low, phosphoric acid is used as a curing accelerator, based on the total paint solids content. 3 pHR was added to.

Using these paints, predetermined painted boards for adhesion testing and worn painted boards were obtained, and then tests were conducted.

As shown in the evaluation results in Table 5, the content of epoxy and phenol in the primer significantly affects the adhesion. I understand the basics. In other words, if the epoxy content is high, even if the primer has high strength at the initial stage of adhesion or after heat treatment, the adhesion between the primer and the metal material surface will be significantly reduced when placed in a retort or hot water. Even when this was used as an adhesive structure for a lid, the openings often became defective due to the decrease in adhesion during heat sterilization. On the other hand, when the phenol ratio in the primer, that is, the content of phenol formaldehyde resin, increased, it became difficult to obtain high adhesive strength, and the opening property with the lid was significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of the adhesion fulcrum between the binding and the opening tab in the easy-to-open binding for a rolled-up can as a metal structure of the present invention; FIG. 2 is an enlarged view of the adhesive structure Electron m in cross section of adhesive layer in object
It is a microscopic photograph. Figure 3 shows the adhesive fulcrum at 9 when using a typical adhesive.
4 is a graph plotting the relationship between the peeling force in the 0 degree direction and the amount of displacement; FIG. The figure is a sectional view taken along line AA' of the binding in FIG. 4.゛

Claims (1)

[Claims] (1) A metal adhesive structure formed by bonding primer-coated metal materials to each other with a polyamide adhesive, where the adhesive has (A) an average main chain carbon number of 6 per amide group;
．． a linear aliphatic polyamide within the range of 1 to 15;
(B) 10 to 400 mmol of at least one group selected from the group consisting of carboxylic acid, carboxylic acid anhydride, carboxylic acid salt, carboxylic acid amide, and carboxylic acid ester bonded to the polymer chain as =CO group; /100g of polymer at a concentration of A:B=
The adhesive layer contains polyamide (A) as a continuous phase and olefin copolymer (B) as a dispersed particle phase, and the primer contains epoxy resin and phenolic resin in a weight ratio of 94:6 to 65:35. 1. A metal adhesive structure characterized by being a curable coating film containing the following in a weight ratio of 95:5 to 30:70.