JP4541638B2 - Aluminum alloy coated plate for can lid - Google Patents

Description

【００３０】
次に，上記１４種類の供試材を用いて，実際に缶成形用のプレス装置によってプレス試験を行った。そして，供試材をフィードさせるときのブロッキングによるフィード不良の発生状況，供試材のプレス時における塗膜剥離の状況，搬送ラインのワックスの堆積状況を調査した。
プレス装置としては，入り側から順に，板を挟んで送るためのフィードロール−蓋加工金型−フィードロール−シアーを備えた連続加工装置を用いた。そして，連続プレス回数は１０万回とした。
【００３１】
調査結果を表１に併記する。
また，評価基準は次のとおりとした。
＜フィード性＞
○：加工部がすべて等間隔で良好な場合。
△：加工部が等間隔でない場合があるが，隣り合う加工部が重ならない場合。
×：隣り合う加工部が１回でも重なる場合。
【００３２】
＜潤滑性＞
○：加工部に全くキズのない場合。
△：加工部にキズがあるが，アルミニウム合金の基板は露出していない場合。
×：加工部にキズがあり，アルミニウム合金基板が露出しており，塗膜剥離の前兆が現れている場合。
【００３３】
＜ワックス堆積＞
○：加工金型にほとんど堆積しない場合。
△：加工金型にワックスが堆積するが，アルミニウム合金基板にキズが発生しない場合。
×：加工金型にワックスが堆積し，アルミニウム合金基板にキズが発生する場合。
【００３４】
＜総合評価＞
◎：すべての評価において○の場合。
○：△が１つ，○が２つの場合。
△：△が２つ，○が１つの場合。
×：１つでも×がある場合。
【００３５】
表１から知られるごとく，インナーワックス含有量あるいはアウターワックス付着量が上記の所定の範囲を下回る供試材１，２，３は，いずれも加工部にキズが入りアルミニウム合金よりなる基板が露出した。
インナーワックス含有量あるいはアウターワックス付着量が上記の所定の範囲を上回る供試材１１，１３，１４は，いずれもワックス堆積が発生した。
【００３６】
これに対し，インナーワックス含有量およびアウターワックス付着量が共に上記所定の範囲内の供試材４，５，６，７，９，１０は，潤滑性，ワックス堆積とも△のレベル以上であり，量産可能なレベルであった。
但し，アウターワックス中へのインナーワックス混合比率が３０％以上の供試材８，１２，１４はフィード性が劣る結果となった。
【００３７】
【発明の効果】
以上のように，本発明によれば，アウターワックスとインナーワックスの両者を施した塗装板であって，プレス加工時の塗膜密着性に優れ，ワックス堆積も未然に防止し，かつプレス加工時のブロッキングをも未然に防止することでフィード不良を解消しうる成形性に優れた缶蓋用アルミニウム合金塗装板を提供することができる。[0001]
【Technical field】
The present invention relates to an aluminum alloy coated plate for can lids, which is formed by applying a water-based or solvent-based paint as a precoat layer and has excellent formability.
[0002]
[Prior art]
Aluminum alloy coated sheets are generally manufactured by hot rolling (hot rolling)-cold rolling (cold rolling), or hot rolling-cold rolling-intermediate annealing-cold rolling, followed by a surface treatment-coating treatment (pre-coating). And having a substrate made of an aluminum alloy plate, a base formed on one or both sides of the substrate, and a precoat layer made of a water-based or solvent-based paint formed thereon.
[0003]
Aluminum alloy coated plates for can lids are pressed without applying a lubricant when forming into can lids. Therefore, it is necessary to impart lubricity to the aluminum alloy coated plate itself before forming.
As a method for imparting lubricity to the coated plate, a method using an outer wax which is a wax additionally applied to the surface of the precoat layer and a method using an inner wax which is a wax previously contained in the paint constituting the precoat There are two types.
[0004]
In the case of press working with high surface pressure, such as can lid molding, the outer wax may be out of wax, that is, the outer wax film on the coated surface cannot be retained, resulting in a problem that the oil film is cut and defective molding occurs. is there.
In recent years, inner wax has been frequently used as an alternative to outer wax in order to solve the problems associated with outer wax such as the above-mentioned wax breakage.
[0005]
Examples of the coating plate containing the inner wax include, for example, a method of controlling the temperature to 110 ° C. or less after 5 seconds and 180 ° C. or less after 10 seconds (see Patent Document 1), and the surface roughness of the aluminum alloy plate. In which the thickness is limited in relation to the plate thickness (see Patent Document 2), a method of controlling the temperature rising rate during baking at a coating amount of 40 to 200 mg / dm ² to 5 to 20 ° C./sec (Patent Document) 3), a composition comprising an aqueous dispersion of a wax aqueous dispersion and a modified epoxy resin using a resin having a limited acid value and number average molecular weight as an emulsifier (see Patent Document 4), and particles of organic lubricating particles on the surface of the coating film There are those having a diameter of 10 μm or less, a distribution density of 50 pieces / mm ² or more, an area ratio of 0.25% or more, and a coating thickness of 0.5 to 15 μm (see Patent Document 5).
[0006]
However, in the aluminum alloy coated plate for can lids, simply adding an inner wax to the coating film may cause defects such as scratches or peeling of the coating film during can lid molding, and further improvements can be made. It was desired.
[0007]
In addition, there is a technique in which various problems at the time of can lid molding are solved by adjusting the application state of the outer wax instead of the above-described method of containing the inner wax (see Patent Document 6). However, it is difficult to reliably eliminate various problems during can lid molding simply by adjusting the application state of the outer wax.
[0008]
[Patent Document 1]
JP 11-244778 A,
[Patent Document 2]
JP 11-285753 A,
[Patent Document 3]
JP 11-319705 A,
[Patent Document 4]
JP-A-11-343455,
[Patent Document 5]
JP 2000-176372 A,
[Patent Document 6]
Japanese Examined Patent Publication No. 6-9716 [0009]
[Problems to be solved]
The present invention has been made in view of such conventional problems, and it is intended to provide an aluminum alloy coated plate for can lids that can prevent peeling of the coating film on the inner wax-containing coated coating plate and has excellent formability. To do.
[0010]
[Means for solving problems]
The present invention relates to an aluminum alloy coated plate for a can lid having a substrate made of an aluminum alloy plate and a precoat layer made of a water-based or solvent-based paint formed on one or both sides of the substrate,
The precoat layer contains 0.1 to 10 parts by weight of inner wax per side with respect to 100 parts by weight of the solid content of the paint, and 5 to 70 mg of outer wax is formed on the surface of the precoat layer. / M ² applied ,
As the inner wax, plant wax, animal wax (excluding lanolin), mineral wax, and synthetic wax are used alone or a mixture thereof.
The mixing ratio of the inner wax to the outer wax is 0.2% or more and less than 30% .
[0011]
In the present invention, as described above, the precoat layer contains the inner wax, and the predetermined amount of the outer wax is applied to the surface of the precoat layer. Thereby, the subject mentioned above can be solved reliably.
That is, if the pre-coat layer only contains the inner wax, the wax distribution on the surface of the paint film (pre-coat layer) becomes uneven, resulting in uneven lubricity, and the paint film is scratched or peeled off when the lid is processed. In some cases, the outer wax is further applied to the surface of the precoat layer to compensate for uneven wax distribution in the case of using only the inner wax, and uniform lubrication performance can be obtained over the entire surface, thereby preventing scratches and coating film peeling. In order to surely exhibit this effect, an outer wax is further applied to the surface of the precoat layer containing the inner wax, and the content of the inner wax is limited to the predetermined range. Therefore, it is necessary to limit the coating amount of the outer wax to the predetermined range.
[0012]
That is, the precoat layer contains 0.1 to 10 parts by weight of inner wax per side with respect to 100 parts by weight of the solid content of the paint. When the content of the inner wax is less than 0.1 parts by weight, the surface of the coated plate is insufficiently lubricated, and even if there is an outer wax, scratches and peeling of the coating are likely to occur during the lid processing. The plate may be constricted or break. On the other hand, when the amount exceeds 10 parts by weight, the phenomenon that the inner wax is mixed into the outer wax as described later becomes prominent, and the mixing amount becomes too large. This not only saturates the above effect due to the presence of both the inner wax and the outer wax, but also causes the wax to accumulate on the transport path of the lid processing line, resulting in trouble in transport. More preferably, the content of the inner wax is 0.1 to 6 parts by weight.
[0013]
An outer wax of 5 to 70 mg / m ^{2 is} applied to the surface of the precoat layer. When the amount of outer wax applied is less than 5 mg / m ² , the above effects due to the presence of both inner wax and outer wax are hardly obtained, and scratches and peeling of the coating only occur during lid processing. This makes it difficult to control the film thickness uniformly in the actual production line. On the other hand, if it exceeds 70 mg / m ² , the above effect due to the presence of both the inner wax and the outer wax is not only saturated, but the outer wax accumulates on the transport path of the lid processing line, and the transport is defective. I will give you. More preferably, the coating amount of the outer wax is 5 to 50 mg / m ² .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
As the outer wax in the present invention, for example, petroleum waxes such as paraffin and petrolatum, and vegetable waxes such as palm oil are often used, but various known waxes can be used as long as they can be used as outer waxes. it can. These can be used alone or as a mixture.
[0015]
The inner wax may be a plant wax such as carnauba, an animal wax such as lanolin, a mineral wax such as microcrystalline, or a synthetic wax such as polyethylene. If the inner wax can be used as an inner wax, Various known waxes can be applied. These can be used alone or as a mixture.
[0016]
Examples of the water-based paint that can be used for the precoat layer include an epoxy acrylic resin.
Examples of the solvent-based paint that can be used for the precoat layer include an epoxy phenol resin, a vinyl organosol resin, an epoxy urea resin, a thermosetting vinyl resin, and a polyester resin.
Moreover, as an aluminum alloy plate used as the said board | substrate, various aluminum alloy plates for can lids, such as an Al-Mg type alloy and an Al-Mn type alloy, are applicable, for example.
[0017]
Next, in the present invention, the mixing ratio of the inner wax to the outer wax is 0.2% or more and less than 30% .
When molding a coated plate of the present invention with both inner wax and outer wax on a can lid, this is a phenomenon where the coated plate or molded product adheres to the parts of the press (roll, guide, etc. with which the coated plate contacts) Blocking may occur, resulting in poor feeding of painted plates and molded products. When feed failure occurs, double strikes occur in the press, resulting in burrs and debris on the coated plate. Therefore, in this case, it is necessary to stop the press once and clean it, which significantly reduces the production efficiency.
[0018]
On the other hand, although not an example in which both the inner wax and the outer wax are applied, the application state of the outer wax described in Patent Document 6 described above is adjusted as a technique for solving the mold separation failure which is a kind of the blocking. How to do is known.
That is, when the outer wax is applied, the coated plate is heated to a temperature equal to or higher than the melting point of the outer wax (for example, about 60 ° C. for paraffin wax), the outer wax is applied, and when the outer wax is wound up into a coil shape, It is necessary to perform the winding operation while maintaining the temperature of the coated plate at a temperature higher than the melting point of the wax. Under this premise, there is a method in which a constant amount of paraffin wax as an outer wax is applied to a continuously coated Al—Mg alloy plate and then wound at a temperature of 60 to 120 ° C. while being held at 60 to 150 ° C. Proposed.
[0019]
However, in actuality, blocking cannot be reliably prevented by the above method alone, and the occurrence of feed failure due to blocking has not been solved.
[0020]
That is, in the past, as described above, it was considered that the coating plate or molded product adhered to the mold due to the coating amount and distribution of the outer wax.
However, in the case of a coated plate with both outer wax and inner wax, the present inventors have conducted intensive research. As a result, the inner wax is mixed into the outer wax, and the mixing ratio of the inner wax becomes 30% or more. This led to the elucidation that the outer wax became sticky.
And because the outer wax was sticky, the coated plate and molded product were likely to adhere to the rolls and guides that are parts of the press machine, causing the feed plate and molded product to have poor feed. It turned out.
[0021]
The above mixing ratio means that the weight per unit area of the outer wax is A (mg / m ² ), and the weight per unit area of the inner wax mixed in the outer wax is B (mg / m ² ). B ÷ (A + B) × 100 (%).
[0022]
As described above, the content and coating amount of the inner wax and outer wax are limited to the specific range, and the mixing ratio of the inner wax to the outer wax is limited to less than 30% as described above. It was found that time blocking can be surely prevented. As a result, the production efficiency of the can lid can be dramatically improved.
[0023]
In order to make the mixing ratio less than 30%, the inner wax content and the outer wax coating amount are controlled to the above predetermined amounts, and if necessary, production conditions such as winding tension after painting and baking in the line There is a way to control.
[0024]
【Example】
The aluminum alloy coated plate for can lids according to the embodiment of the present invention will be described more specifically.
In this example, 14 types of test materials with different amounts of outer wax and inner wax were prepared, and the mixing ratios were also made different. A press test was conducted to investigate the situation.
[0025]
First, as a substrate made of an aluminum alloy plate, an aluminum alloy coil of material A5182, grade H19, plate thickness of 0.25 mm is prepared, and the substrate is coated, uncoated, and coated on the continuous coating line. Wax was applied, and it was wound around the coil again.
[0026]
As the base treatment, a general chromate treatment was performed on both surfaces of the substrate under the condition of about 20 mg / m ² .
As the coating process, when the substrate is molded into a can lid, about 100 mg / dm ^{2 of} vinyl chloride organosol resin is provided on the inner surface of the substrate, and about 45 mg of epoxy urea resin is formed on the outer surface of the can lid. After coating / baking / dm ² , outer wax was applied to both sides. Each resin on both sides was made to contain a predetermined amount of carnauba as an inner wax. A predetermined amount of paraffin was applied as the outer wax.
[0027]
Next, the outer wax adhesion amount of the resin on the lid inner surface side and the lid outer surface side and the mixing ratio of the inner wax in the outer wax on the coated plate obtained by winding the coil after coating were measured. The results are shown in Table 1. PHR in Table 1 is an abbreviation for PER HUNDRED REGIN, and is a unit widely used as the content (parts by weight) of the inner wax with respect to 100 parts by weight of the solid content of the resin.
[0028]
The measuring method of the outer wax adhesion amount and the mixing ratio of the inner wax into the outer wax is as follows.
Wash and collect the outer wax adhering to one side (surface) with a certain amount of hexane. Paraffin wax used as an outer wax dissolves in hexane and can be almost recovered. Moreover, the inner wax mixed in the outer wax is also collected together with the outer wax. The hexane containing the outer wax and inner wax thus recovered was heated to 80 ° C. and concentrated, and then the outer wax and inner wax were dissolved or dispersed in carbon tetrachloride and analyzed by gas chromatogram.
[0029]
[Table 1]

[0030]
Next, a press test was actually performed by using a press for can molding using the above 14 kinds of test materials. Then, the occurrence of feed failure due to blocking when feeding the test material, the state of coating film peeling during pressing of the test material, and the state of wax accumulation on the transport line were investigated.
As the pressing device, a continuous processing device provided with a feed roll, a lid processing mold, a feed roll, and a shear for sandwiching and feeding the plates in order from the entry side was used. The number of continuous presses was 100,000.
[0031]
The survey results are also shown in Table 1.
The evaluation criteria were as follows.
<Feed properties>
○: When all the processed parts are good at regular intervals.
Δ: Processed parts may not be equally spaced, but adjacent processed parts do not overlap.
X: When adjacent processed parts overlap even once.
[0032]
<Lubricity>
○: When there is no scratch in the processed part.
Δ: The processed part is scratched, but the aluminum alloy substrate is not exposed.
×: When there is a scratch in the processed part, the aluminum alloy substrate is exposed, and a sign of coating film peeling appears.
[0033]
<Wax accumulation>
○: Almost no deposit on the processing mold.
Δ: Wax accumulates on the working mold, but the aluminum alloy substrate is not scratched.
×: When wax accumulates on the processing mold and scratches occur on the aluminum alloy substrate.
[0034]
<Comprehensive evaluation>
A: In the case of ○ in all evaluations.
○: When Δ is one and ○ is two.
Δ: When Δ is two and ○ is one.
X: When there is even one x.
[0035]
As is known from Table 1, the test materials 1, 2, and 3 in which the inner wax content or the outer wax adhesion amount is lower than the above-described predetermined range, both of which are scratched in the processed portion and the substrate made of an aluminum alloy is exposed. .
In each of the test materials 11, 13, and 14 in which the inner wax content or the outer wax adhesion amount exceeded the predetermined range, wax deposition occurred.
[0036]
On the other hand, the specimens 4, 5, 6, 7, 9, and 10 in which the inner wax content and the outer wax adhesion amount are both within the above predetermined range are both above the level of Δ for both lubricity and wax accumulation, It was a level that could be mass-produced.
However, the test materials 8, 12, and 14 in which the mixing ratio of the inner wax into the outer wax was 30% or more resulted in poor feedability.
[0037]
【The invention's effect】
As described above, according to the present invention, a coated plate provided with both an outer wax and an inner wax, which is excellent in coating film adhesion at the time of pressing, prevents wax accumulation, and at the time of pressing. It is possible to provide an aluminum alloy coated plate for can lids that is excellent in formability that can eliminate poor feeding by preventing the blocking of the above.

Claims (3)

In an aluminum alloy coated plate for a can lid, comprising: a substrate made of an aluminum alloy plate; and a precoat layer made of a water-based or solvent-based paint formed on one or both sides of the substrate,
The precoat layer contains 0.1 to 10 parts by weight of inner wax per side with respect to 100 parts by weight of the solid content of the paint, and 5 to 70 mg of outer wax is present on the surface of the precoat layer. / M ² applied ,
As the inner wax, plant wax, animal wax (excluding lanolin), mineral wax, and synthetic wax are used alone or a mixture thereof,
An aluminum alloy coated plate for a can lid, wherein the mixing ratio of the inner wax to the outer wax is 0.2% or more and less than 30% .   2. The aluminum alloy coated plate for a can lid according to claim 1, wherein the inner wax is one of carnauba, microcrystalline, and polyethylene, or a mixture thereof.   3. An aluminum alloy coated plate for a can lid according to claim 1, wherein said outer wax is made of paraffin, petrolatum, and palm oil alone or a mixture thereof.