WO2010071150A1

WO2010071150A1 - Precoated aluminum plate

Info

Publication number: WO2010071150A1
Application number: PCT/JP2009/070974
Authority: WO
Inventors: 伸郎服部
Original assignee: 株式会社神戸製鋼所
Priority date: 2008-12-18
Filing date: 2009-12-16
Publication date: 2010-06-24
Also published as: MY161076A; TW201343968A; TW201038768A; CN102245380A; TWI494472B; TWI424086B

Abstract

A precoated aluminum plate (1) has a precoated film (3) on an aluminum plate (2), wherein the precoated film includes molecular cross-linked base resin (4) and particles (5), wherein said precoated film (3) includes 50% or more of gel fraction and has a surface roughness of 0.25 μm or more in the arithmetic average (Ra).

Description

Pre-coated aluminum plate

The present invention relates to a pre-coated aluminum sheet made of an aluminum sheet, which is mainly used for industrial electronic devices, consumer electronic devices, automobile electrical components and the like.

As housings (covers and the like) for consumer electronic devices such as optical disk drive devices assumed in Patent Document 1 and Patent Document 2, aluminum plates formed into a box shape by bending 90 degrees have been applied. . The technology for producing box-type housings by bending is to use a coiled plate, continuous molding with progressive molds is possible, and continuous molding technology using quick-drying press oil has been established. Therefore, a cleaning process after press molding is unnecessary, and it can be said that the method is excellent in productivity. However, on the other hand, since the case manufactured by bending always has a gap in the corner of the side wall, the following problems arise when the case needs to be sealed.

Examples of cases in which high sealing performance is required for the housing include, for example, automotive control electrical components installed in harsh environments such as engine rooms (control devices such as ECUs, hybrid and electric vehicle batteries, inverters, etc. In these cases, if the airtightness inside the housing cannot be maintained, moisture, oils, dust and the like may enter the housing and cause a failure. Aluminum plate molded products are also used for lithium ion batteries and electrolytic capacitor cases. However, in applications where liquids such as electrolytes are placed inside, as in these cases, in order to prevent liquid leakage, However, the case is required to have high sealing performance. Further, even in consumer electronic devices used in a room such as a home, it is expected that the electromagnetic wave shielding property can be improved by enhancing the sealing property of the cover. As described above, in order to manufacture a case with high hermeticity, a method of forming a box-type case without a gap by drawing rather than bending is advantageous. FIG. 3A is a schematic diagram of a box-shaped housing by bending, and FIG. 3B is a schematic diagram of a box-shaped housing by drawing.

Here, when applying a pre-coated aluminum plate to these cases, it is required that the pre-coated film not only follows the large deformation accompanying the drawing process, but also the pre-coated film. Examples of Patent Document 3 and Patent Document 4 are listed below as documents related to the invention assuming drawing.
As a pre-coated aluminum plate that assumes a large deformation of the pre-coated film associated with the drawing process, for example, Patent Document 3 discloses a gel fraction of the pre-coated film as an intermolecular cross-linked state of a thermosetting resin formed on the surface of the aluminum plate ( When the value of Gel Fraction) is compared before and after the heat treatment at 220 ° C., the value of the gel fraction after the heat treatment is continuously reduced from the value of the gel fraction before the heat treatment. The pre-coating satisfying high drawability by controlling the reduction rate from the value of the gel fraction before the heat treatment at the time of performing the heat treatment at 220 ° C. for 10 minutes to be less than 10%. An aluminum plate is disclosed.

As a technique other than the pre-coated aluminum material mentioned above, a film laminated aluminum plate obtained by laminating a thermoplastic resin film excellent in workability is used in the case of an electrolytic capacitor. The film-laminated aluminum plate has a characteristic that is advantageous for drawing because the resin molecules constituting the film are not cross-linked, and thus the film can be greatly deformed. Some of them have improved durability of cleaning chemicals with chlorinated solvents. For example, Patent Document 4 includes a thermoplastic resin film provided on the surface of an aluminum plate and a thermosetting resin coating layer provided on the surface of the thermoplastic resin film, thereby maintaining moldability. On the other hand, a resin-coated laminated aluminum plate for an electronic component case that prevents the discoloration of the resin coating layer has been disclosed. Further, it is described that a polyamide resin such as nylon or a saturated polyester resin such as PET is used as the thermoplastic resin film.
JP 2003-313684 A (paragraphs 0020 to 0050) Japanese Patent No. 4134237 (paragraphs 0024 to 0042) JP 2006-305841 A (paragraphs 0024 to 0051) Japanese Patent No. 4003915 (paragraphs 0017 to 0029)

However, the conventional technique has the following problems.
The inventions described in Patent Literature 1 and Patent Literature 2 are inventions that assume an optical disk drive as their application, and as described above, are considered to be inventions that presuppose that the housing is manufactured by bending. In the case of bending, as described above, it is considered that only molding with a quick-drying press oil is assumed. Therefore, it is considered that durability with a boiling chlorine-based cleaning chemical is not considered.

The invention described in Patent Document 3 assumes drawing. In the drawing process where the deformation amount of the aluminum plate is large, the continuous forming technique using the quick-drying press oil as described in the case of the bending process has not been sufficiently established. Therefore, many methods are still employed in which unnecessary pressing oil and abrasion powder are removed using a cleaning agent after molding using high-viscosity rust preventive oil or emulsion type wax. In such a method, it is not sufficient that the precoat film satisfies the moldability capable of following a large deformation, and the film is dissolved, peeled, discolored, and stuck to the chemical used in the cleaning process. The durability of the film in the cleaning process is indispensable. Here, in the cleaning process, when performing a harsh cleaning method such as immersing in a boiling liquid of a chlorinated solvent such as trichlene, the technique described in Patent Document 3 dissolves, peels off the film of the molded article, Discoloration, sticking, etc. may occur, causing appearance defects.

As described in Patent Document 4, a film laminate material made of a thermoplastic resin as a base resin and laminated on the surface of an aluminum plate uses a thermoplastic resin film. Naturally there is a limit. For example, when a polyamide-based thermoplastic resin typified by nylon is used as a base resin, it has good adhesion to an aluminum plate and has excellent moldability. There is a problem that the base resin is easily yellowed or browned. Furthermore, when a saturated polyester-based thermoplastic resin such as PET is used as the base resin, it has good adhesion to the aluminum plate, exhibits excellent moldability, and does not easily discolor the base resin even in high-temperature environments. However, since the base resin is easily hydrolyzed, it tends to be inferior in durability under a high-temperature and humid atmosphere.

In addition, when a polyolefin resin typified by polyethylene or polypropylene is used as a base resin, the base resin is basically composed of only carbon and hydrogen and does not contain nitrogen or oxygen. Therefore, there is no origin of functional groups and chemical bonds such as hydroxyl groups, carboxyl groups, ester bonds, isocyanate groups, urethane bonds, amino groups, and amide bonds, and the adhesiveness to the aluminum plate is poor.

Therefore, it is a pre-coated aluminum plate using a thermosetting resin with higher heat resistance and durability than the film laminate material, and it is washed during the process of washing and removing press oil and wear powder etc. in the cleaning agent after press molding. Precoated aluminum with excellent film durability in the cleaning process that can prevent surface abnormalities such as dissolution, peeling, discoloration, and sticking of the precoat film even when cleaning in a high-capacity boiling chlorine-based cleaning agent Development of the board is desired. Furthermore, in addition to the excellent durability of the coating film in the cleaning process, a precoated aluminum plate that has excellent formability in drawing and does not impair the beautiful gloss appearance of the aluminum plate is more desired.

The present invention has been made in view of the above problems, and in a precoated aluminum plate using a thermosetting resin, in a boiling chlorine-based cleaning agent, no dissolution, peeling, discoloration, sticking, etc. of the film occurs. It aims at providing the precoat aluminum plate excellent in the durability of the film | membrane in the washing | cleaning process.
Furthermore, as a more desirable form, pre-coated aluminum that has excellent durability of the film in the cleaning process, and has high formability comparable to that of a film laminate material and excellent appearance properties even when drawn. The purpose is to provide a board.

In addition, a thermosetting resin mainly composed of an epoxy resin that has excellent durability under a high-temperature and humid atmosphere is used to provide a pre-coated aluminum plate that has both high moldability and heat-resistant discoloration properties and excellent chemical resistance. For the purpose.

First solution

(1) The pre-coated aluminum plate according to the first solution is formed on the surface of the aluminum plate with a pre-coated film (hereinafter referred to as a film as appropriate) containing a base resin that has been cross-linked and formed with fine particles. The precoated aluminum plate is characterized in that the precoated film has a gel fraction of 50% or more and a surface roughness of 0.25 μm or more in terms of arithmetic average roughness (Ra). To do.

According to such a configuration, when the gel fraction of the precoat film is 50% or more, the crosslink density of the precoat film is increased, and the fine particles added to the precoat film are prevented from falling off during the cleaning process. Can do. In addition, chemical resistance, heat resistance, hydrolysis resistance and the like are improved, and durability of the film in the cleaning process is improved. Furthermore, by adding fine particles, the surface roughness (arithmetic average roughness (Ra)) of the precoat film is controlled, and when the surface roughness Ra is 0.25 μm or more, the surface roughness of the precoat film is reduced. It becomes sufficiently large, and sticking between the films in the boiling chlorine-based cleaning agent is suppressed.

(2) The fine particles are preferably inorganic fine particles or crosslinked organic fine particles.
According to such a configuration, the fine particles are not melted by heat when the base resin is subjected to a crosslinking reaction, and the surface roughness Ra of the precoat film can be easily controlled.

(3) The fine particles are preferably crosslinked spherical organic fine particles.
According to such a structure, the form of the convex part of a precoat film | membrane becomes smooth and the burden of the metal mold | die for press molding is reduced.

(4) The base resin is preferably a crosslinked polyester resin obtained by crosslinking a polyester resin having a glass transition temperature of 25 to 65 ° C. with a melamine curing agent or an isocyanate curing agent.
(5) The polyester resin preferably has a glass transition temperature of 35 to 60 ° C.
According to such a configuration, the film becomes moderately flexible, and the drawability of the precoated aluminum plate is improved.

(6) The surface roughness of the precoat film is preferably an arithmetic average roughness (Ra) of 0.25 to 0.55 μm.
According to such a configuration, the irregular reflection of visible light on the surface of the precoat film is suppressed, and the precoat film is suppressed from being matted. Here, the matte state means that the gloss of the aluminum plate as the material is lost.

(7) In the precoat film, the proportion of the fine particles is preferably 1 to 50% by mass.
According to such a configuration, the surface roughness Ra of the precoat film can be easily set to 0.25 μm or more by setting the ratio of the fine particles to 1% by mass or more. On the other hand, when the proportion of the fine particles is 50% by mass or less, the fine particles can be easily fixed to the base resin.

(8) The particle diameter of the fine particles is preferably 1 to 50 μm.
According to such a configuration, considering that the film thickness that can be applied with a general roll coater is about 1 to 20 μm by setting the particle size of the fine particles to 1 μm or more, the target film of the precoat film Even in the case of a relatively thin film thickness of 1 μm, the surface roughness Ra of the precoat film can be easily set to 0.25 μm or more. On the other hand, by setting the ratio of the fine particles to 50% by mass or less, the fine particles can be easily fixed to the base resin even if the target film thickness is 20 μm.

(9) The precoat film preferably has a thickness of 1 to 20 μm.
In general, the thickness of the film that can be applied by one application operation is generally 1 to 20 μm. Therefore, workability and productivity can be improved with the above configuration.

Second solution

(10) The pre-coated aluminum plate according to the second solution is a pre-coated aluminum plate in which a pre-coated film is formed on the surface of the aluminum plate, and the pre-coated film is an epoxy resin and a non-yellowing type The isocyanate-based curing agent is made of a thermosetting resin that is cross-linked between molecules, and the gel fraction of the precoat film is 70% or more and 92% or less.

According to such a configuration, the precoat film is made of a thermosetting resin in which an epoxy resin is cross-linked between molecules, whereby durability in a high-temperature and humid atmosphere is improved. The precoat film is composed of a thermosetting resin in which an epoxy resin and a non-yellowing type isocyanate curing agent are cross-linked between molecules, and the gel fraction of the precoat film is 70% or more and 92% or less. The epoxy resin is flexible, has high drawability, is excellent in chemical resistance, and can avoid discoloration in a heat test.

(11) The gel fraction of the precoat film is preferably 70% or more and 85% or less.
According to such a configuration, the film can follow deep drawing with a larger amount of deformation by setting the gel fraction of the precoat film to 70% or more and 85% or less.

(12) The non-yellowing type isocyanate curing agent is preferably a block type isocyanate compound.
According to such a configuration, when the paint (resin solution) is stored at room temperature by using a block-type isocyanate compound as the non-yellowing type isocyanate curing agent, the isocyanate curing agent and the epoxy resin Can be prevented from reacting and curing, and since the curing reaction proceeds quickly in the heating process in the painting line, the paint storage life can be greatly extended while maintaining rapid bake curability. .

(13) The precoat film contains inorganic fine particles or fine particles which are crosslinked organic fine particles in the thermosetting resin serving as a base resin, and the surface roughness is an arithmetic average roughness (Ra). It is preferable that it is 0.25 μm or more.
According to such a configuration, the surface roughness (arithmetic average roughness (Ra)) of the precoat film is controlled by adding fine particles, and the surface roughness Ra is 0.25 μm or more, so The surface roughness of the film becomes sufficiently large, and adhesion between the films in the boiling chlorine-based cleaning agent is suppressed.

(14) The fine particles are preferably cross-linked spherical organic fine particles.
According to such a structure, the form of the convex part of a precoat film | membrane becomes smooth and the burden of the metal mold | die for press molding is reduced.

(15) The surface roughness of the precoat film is preferably an arithmetic average roughness (Ra) of 0.25 to 0.55 μm.
According to such a configuration, the irregular reflection of visible light on the surface of the precoat film is suppressed, and the precoat film is suppressed from being matted. Here, the matte state means that the gloss of the aluminum plate as the material is lost.

Effect of the first solution

According to the invention of the above constitution (1) in the first solution means, even when washing is performed in a harsh boiling chlorine-based cleaning agent, dissolution, peeling, discoloration, sticking, etc. of the film do not occur. It is possible to provide a pre-coated aluminum plate with excellent film durability in the cleaning process. Thereby, since the manufacturing process which can be selected spreads, the application field of a precoat aluminum plate spreads. In addition, since the basic chemical resistance of the film has been improved, not only the durability of the film in the cleaning process after press molding is improved, but also the solvent resistance and chemical resistance in the actual use environment are improved. .
According to the invention of the configuration (2) in the first solving means, the surface roughness Ra of the precoat film can be easily controlled, and a precoat film having a stable surface roughness Ra can be obtained.
According to the invention of the configuration (3) in the first solving means, the burden on the press molding die can be reduced, so that the life of the press molding die can be improved.

According to the inventions of the above constitutions (4) and (5) in the first solving means, the flexibility of the precoat film can be obtained moderately, and the drawability of the precoat aluminum plate can be improved. Therefore, it is possible to provide a precoated aluminum plate that can follow forming with large deformation such as drawing and ironing. As a result, it is possible to provide a casing with excellent hermeticity that is suitable for casings for industrial electronic devices, consumer electronic devices, and automobile electrical components. In addition, it is possible to provide a molded article having excellent heat discoloration resistance and hydrolysis resistance as compared with a film laminated aluminum plate.
According to the invention of the configuration (6) in the first solving means, it is possible to provide a molded product having a beautiful gloss appearance of the aluminum plate.

According to the inventions of the above constitutions (7) and (8) in the first solving means, considering that the film thickness that can be applied with a general roll coater is approximately 1 to 20 μm, the precoat film Even when the target film thickness is 1 μm and a relatively thin film thickness, the surface roughness Ra of the precoat film can be easily set to 0.25 μm or more. On the other hand, the fine particles can be easily fixed to the base resin even when the target film thickness is a relatively large film thickness of 20 μm.
According to the invention of the configuration (9) in the first solving means, workability and productivity can be improved.

Effect of the second solution

According to the invention of the configuration of the above (10) in the second solution means, it has excellent draw forming (working) properties, is excellent in durability under a high-temperature and humid atmosphere, has both chemical resistance, And the precoat aluminum plate which does not produce discoloration by a heat test can be provided. As a result, it is possible to supply a light and highly airtight casing that is excellent in reliability even in outdoor or in-vehicle environments at low cost and with excellent productivity.
According to the invention of the configuration of the above (11) in the second solving means, it is possible to provide a precoated aluminum plate having a further (further) excellent drawability. As a result, the degree of freedom in designing the shape of the hermetically sealed housing is increased, and various shapes of the housing can be obtained, and the applicable range of the housing is expanded.
According to the invention of the above constitution (12) in the second solving means, the shelf life of the paint forming the precoat film is improved. As a result, the risk that the paint will expire and become unusable is reduced, leading to a total cost reduction. In addition, since industrial waste is reduced, it leads to environmental improvement.

According to the invention of the above configuration (13) in the second solution means, even when washing is performed in a harsh boiling chlorine-based cleaning agent, dissolution, peeling, discoloration, sticking, etc. of the film do not occur. It is possible to provide a pre-coated aluminum plate with excellent film durability in the cleaning process. Thereby, since the manufacturing process which can be selected spreads, the application field of a precoat aluminum plate spreads. In addition, since the basic chemical resistance of the coating is improved, not only the durability of the coating is improved in the cleaning process after press molding, but also the chemical resistance in the actual use environment is improved. Furthermore, the surface roughness Ra of the precoat film can be easily controlled, and a precoat film having a stable surface roughness Ra can be obtained.
According to the invention of the above configuration (14) in the second solving means, the load on the press molding die can be reduced, so that the life of the press molding die can be improved.
According to the invention of the configuration (15) in the second solving means, it is possible to provide a molded product having a beautiful gloss appearance of the aluminum plate.

It is a fragmentary sectional view which shows typically the structure of the precoat aluminum plate which concerns on this invention. In an Example, it is a schematic diagram which shows the process of producing a bottomed cylindrical container by carrying out drawing processing and ironing of a test material. (A) is a schematic diagram which shows the box-type housing | casing by a bending process, (b) is a schematic diagram which shows the box-type housing | casing by a drawing process.

DESCRIPTION OF SYMBOLS 1 Precoat aluminum plate 2 Aluminum plate 3 Precoat film 4 Base resin 5 Fine particle

First embodiment

Hereinafter, the best mode of the precoated aluminum plate according to the present invention will be specifically described with reference to the drawings as appropriate.
In the drawings to be referred to, FIG. 1 is a partial cross-sectional view schematically showing a configuration of a precoated aluminum plate according to the present invention.

≪Pre-coated aluminum plate≫
As shown in FIG. 1, a precoated aluminum plate 1 has a surface of an aluminum plate 2 on which a precoat film 3 including an intermolecular cross-linked base resin 4 and fine particles 5 is formed. Here, the surface of the aluminum plate 2 means at least one surface of the aluminum plate 2. Each configuration will be described below.

<Aluminum plate>
The aluminum plate 2 referred to in the present invention is made of aluminum or an aluminum alloy, and the aluminum plate (aluminum plate or aluminum alloy plate) 2 used in the present invention is not particularly limited, and may be a product shape or a molding. The method can be selected based on the strength required at the time of use. In general, a non-heat treatment type aluminum plate, that is, a 1000 series industrial pure aluminum plate, a 3000 series Al—Mn alloy plate, and a 5000 series Al—Mg alloy plate can be preferably used. . In particular, when manufacturing a case having a deep container shape with an ironing process, aluminum plates such as A1050, A1100, A3003, and A3004 defined in JIS H4000 are recommended. Moreover, when producing a comparatively shallow container-shaped housing | casing, aluminum plates, such as A5052 and A5182, prescribed | regulated to JISH4000 are recommended. Various types of tempering (thermal refining) and plate thickness can be selected and used according to the purpose. Further, as will be described later, the aluminum plate 2 may be subjected to reactive base treatment, coating type base treatment, anodizing treatment, electrolytic etching treatment, degreasing treatment, and the like.

<Precoat film>
The precoat film 3 (film 3) includes a base resin 4 and fine particles 5 dispersed in the base resin 4, and is formed on the surface of the aluminum plate 2. This precoat film 3 has a gel fraction of 50% or more and a surface roughness of 0.25 μm or more in terms of arithmetic average roughness (Ra).

[Base resin]
The base resin 4 is a main component of the precoat film 3 and uses a conventionally known intercoat type resin used for a precoat aluminum plate or a precoat steel plate, and has a gel fraction of 50 as described later. The intermolecular cross-linking reaction is performed so as to be at least%.

There are film laminates that use thermoplastic resins as the base resin as those that do not undergo intermolecular crosslinking by thermosetting reaction, but as described in the above-mentioned prior art, those using thermoplastic resins as the base resin have various points. This creates a practical problem. However, if a resin that performs intermolecular crosslinking by thermosetting reaction or the like is selected as the base resin 4, this resin originally has a functional group for intermolecular crosslinking, and thus has excellent adhesion to the aluminum plate 2. . Moreover, by cross-linking, chemical resistance and heat resistance can be increased, and hydrolysis resistance can be improved.

The intermolecular cross-linking resin used for the base resin 4 can be selected according to the usage environment and application after pressing. For example, it is desirable to use an epoxy-based resin for the base resin 4 if the hardness and heat resistance of the coating 3 are required. For applications that require weather resistance, antifouling properties, etc., the base resin It is desirable to use a fluorine-based resin for 4. Furthermore, when the product shape is strict and is used after being molded into a complicated shape, it is desirable to use a polyester-based resin that forms a relatively flexible coating 3 as the base resin 4.

Here, when considering the product shape, as described above, in the case of forming into a box shape by bending, since continuous forming technology using quick-drying press oil has been established, sufficient cleaning If it is not an application that requires a state, a cleaning step after press molding is not necessarily required. In other words, it can be said that the shape of products molded using high-viscosity rust preventive oil or emulsion type wax that needs to be cleaned is often complex shapes such as deep-drawn shapes. . Therefore, it is considered that the durability of the coating 3 in the cleaning step in the precoated aluminum plate 1 is combined with a polyester resin capable of obtaining high moldability in a more desirable form.

As the polyester resin, it is desirable to use a saturated polyester resin obtained by condensation polymerization of a polyhydric alcohol and a polybasic acid. Among these, polyhydric alcohols include, for example, dihydric alcohols such as ethylene glycol, propylene glycol, neopentyl glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol, glycerin, trimethylolethane, Trihydric alcohols such as methylolpropane, and tetrahydric or higher alcohols can be used. Examples of polybasic acids include dibasic acids such as phthalic anhydride, isophthalic acid, terephthalic acid, adipic acid, and sebacic acid, tribasic acids such as trimellitic anhydride, and tetravalent or higher polybasic acids. A basic acid or the like can be used. These polyhydric alcohols and polybasic acids may be subjected to condensation polymerization by using one kind or two or more kinds at the same time. Moreover, the glass transition temperature of a polyester resin changes by combining these components.

The glass transition temperature is one of the transition temperatures of the resin. Generally, a resin at a temperature higher than the glass transition temperature is a soft rubber, and a resin at a temperature lower than the glass transition temperature is a hard glass. Therefore, in order for the film 3 to follow a process with large deformation such as deep drawing or ironing, it is theoretically necessary to set the glass transition temperature to the processing temperature or lower. However, in reality, the high molecular structure of macromolecular substances is not uniform, for example, because the molecular weight has a wide range and a branched structure is formed in the molecule. Absent. Therefore, the glass transition temperature is merely a representative value, and the transition gradually occurs in a temperature range having a certain width. In addition, the polyester resin has a relatively high elongation except for a part of the state (a state in which crystallization is promoted in a state of a thermoplastic resin that does not cause a cross-linking reaction) even if it is glassy below the glass transition temperature. Therefore, within a certain range, molding is possible even if a resin having a high glass transition temperature is used as the base resin 4. On the other hand, when the resin having an excessively low glass transition temperature is used as the base resin 4, the coating 3 becomes too soft and wrinkles are likely to enter.

In the present invention, when a polyester resin is used as the base resin 4, the glass transition temperature is preferably in the range of 25 to 65 ° C. If the glass transition temperature is less than 25 ° C., the film 3 becomes too soft and easily wrinkles. On the other hand, if it exceeds 65 ° C., the workability of the precoated aluminum plate 1 is reduced, and the formable shape is limited. The glass transition temperature is more preferably 35 to 60 ° C. By setting the glass transition temperature to 35 ° C. or higher, the flexibility of the film 3 can be made more appropriate, and by setting the glass transition temperature to 60 ° C. or lower, the workability of the precoated aluminum plate 1 can be easily improved. In addition, the glass transition temperature here means what was measured by DSC method.

Moreover, the crosslinking reaction does not occur only with the polyester resin. In order to cause the crosslinking reaction required in the present invention, a curing agent that reacts with the hydroxyl group or carboxyl group of the polyester resin is added, or a component having the same function as the curing agent is generated in the polyester resin itself. In addition, it is necessary to modify the polyester resin using a chemical reaction. Functional groups that react with these hydroxyl groups and carboxyl groups include isocyanate groups, amino groups, hydroxyl groups, carboxyl groups, etc., and can be easily crosslinked by adding a substance having three or more of these functional groups as a curing agent. It is possible to promote the reaction. Examples of such a curing agent include polyisocyanate compounds, melamine compounds, epoxy compounds, amino compounds, phenol compounds, urea compounds, and the like. In addition, when using polyester-type resin for the base resin 4 by this invention, it is desirable that the hardening | curing agent is a melamine type hardening | curing agent or an isocyanate type hardening | curing agent. These curing agents are advantageous in that they can be easily made into a paint, have both storability at room temperature and immediate reactivity at the baking temperature, and hardly cause discoloration by baking.

[Fine particles]
The fine particles 5 are for controlling the surface roughness Ra of the precoat film 3 in a predetermined manner, and are contained in the base resin 4 of the precoat film 3.
As a method for controlling the surface roughness without containing the fine particles 5 in the precoat film 3, a method of physically roughening the surface by blasting or the like after forming the precoat film, or a roll having unevenness A method of transferring the roughness of the roll by pressing the film onto the surface of the film is conceivable. However, the precoat film whose surface roughness Ra is adjusted by these methods has a problem that the unevenness of the film surface becomes smooth in the cleaning solvent, and the predetermined surface roughness in the precoat film cannot be maintained. As a result, the coating surfaces become smooth, and the coating surfaces tend to stick to each other in the boiling chlorine-based cleaning agent. However, in the precoat film 3 in which the fine particles 5 are contained in the base resin 4, the uneven shape of the film surface does not change before and after the solvent cleaning, and therefore, even in the cleaning process using the boiling chlorine-based cleaning agent, Sticking can be prevented.

The type, form, size, amount of addition, etc. of the fine particles 5 are not particularly limited as long as the surface roughness Ra of the precoat film 3 can be controlled within a predetermined range by containing the fine particles 5 in the base resin 4. Good. Thereby, sticking of the films 3 in the boiling chlorine-based cleaning agent can be prevented. However, the type of the fine particles 5 is desirably inorganic fine particles or crosslinked organic fine particles. The other fine particles 5 include thermoplastic fine particles that are not cross-linked. However, when thermoplastic fine particles are used, the fine particles 5 are melted by the heat generated when the base resin 4 is subjected to a cross-linking reaction. Is not stable, and it is likely to be difficult to control the surface roughness Ra of the precoat film 3. In the case of inorganic fine particles or crosslinked organic fine particles, the fine particles 5 are not melted by the heat when the base resin 4 of the precoat film 3 is subjected to a crosslinking reaction, so that the precoat film 3 having a stable (uniform) surface roughness Ra is formed. Obtainable.

When inorganic fine particles are used as the fine particles 5, the convex portions of the precoat film 3 become hard. Therefore, in order to improve the life of the press molding die, it is more desirable that the fine particles 5 are crosslinked organic fine particles. Furthermore, it can be said that when the shape of the fine particles 5 is spherical, the shape of the convex portion of the precoat film 3 when viewed microscopically becomes smooth, and therefore the influence on the mold life is small. Therefore, it is more desirable that the fine particles 5 are cross-linked spherical organic fine particles.

As such crosslinked spherical organic fine particles, for example, crosslinked urethane fine particles, crosslinked acrylic fine particles, silicone fine particles, crosslinked polystyrene fine particles and the like can be suitably used. As examples of crosslinked urethane fine particles, DAIMICBEAZ (registered trademark) (Daiichi Seika), Art Pearl (registered trademark) (Negami Kogyo), etc., manufactured by Dainichi Seika Co., Ltd. can be suitably used. Examples of crosslinked acrylic fine particles include TAFTIC (registered trademark) AR (Toyobo), Riosphere (LIOSPHERE (registered trademark)) manufactured by Toyobo, Art Pearl (ART, PEARL, registered trademark) (Negami Kogyo) Techpolymer (registered trademark) (Sekisui Plastics Industry) can be used suitably. Examples of silicone fine particles include silicone powder (Shin-Etsu Chemical) and TORAYFIL (registered trademark) (Toray Dow Corning). (Dow Corning)) and the like can be preferably used. Non-spherical organic fine particles include, for example, silicone rubber powder (X-52-875 (Shin-Etsu Silicone)), PTFE powder (KT-300M (Kitamura)), cellulose powder (KC Flock (registered trademark) (Nippon Paper Industries). Chemical)), flat polyethylene particles (Sumitomo Seika) and the like. Examples of the inorganic fine particles include nickel powder and talc powder, and examples of the non-crosslinked organic fine particles include thermoplastic urethane beads and polystyrene latex.

Although there is no restriction | limiting in particular about the compounding ratio of the microparticles | fine-particles, If the ratio occupied to the precoat film 3 is less than 1 mass%, it is difficult to make surface roughness Ra 0.25 micrometer or more, and the boiling chlorine type | system | group cleaning agent was used. In the cleaning process, the surfaces of the precoat film 3 are easily adhered to each other. On the other hand, when it exceeds 50 mass%, it becomes difficult to fix the fine particles 5 to the base resin 4. Therefore, the blending ratio is desirably 1 to 50% by mass. In addition, it is more desirable that the content is 3 to 30% by mass, and it is possible to suppress the appearance of the film 3 from being matted and to prevent the beautiful gloss appearance of the aluminum plate 2 as a material from being disturbed. More desirably, the content is 3 to 10% by mass.

The particle diameter of the fine particles 5 is not particularly limited, but considering that the film thickness that can be applied with a general roll coater is approximately 1 to 20 μm, the precoat film 3 is used when the average particle diameter is less than 1 μm. Even when the target film thickness is relatively thin as 1 μm, it is difficult to make the surface roughness Ra 0.25 μm or more. On the other hand, when the average particle diameter exceeds 50 μm, it is difficult to fix the fine particles 5 to the base resin 4 even when the target film thickness is 20 μm and a relatively thick film thickness. Therefore, the average particle size is desirably 1 to 50 μm. In view of suppressing the appearance of the coating 3 from being matted and not disturbing the beautiful gloss appearance of the aluminum plate 2 as a material, the average particle size is desirably 1 to 30 μm. More desirably, it is 2 to 10 μm. Here, the average particle diameter is an integrated volume 50% particle diameter measured with a laser diffraction particle size distribution measuring instrument or the like in a state where the fine particles 5 are dispersed in water.

[Gel fraction of precoat film: 50% or more]
In the present invention, the gel fraction of the precoat film 3 is 50% or more. Here, since the precoat film 3 contains the fine particles 5 in addition to the base resin 4 as an essential component, it is difficult to measure the gel fraction of the base resin 4 only in a strict sense. Therefore, in the present invention, the gel fraction of the precoat film 3 is substituted and defined by this gel fraction.
If the gel fraction of the precoat film 3 is 50% or more, the crosslink density of the film 3 is high, and the fine particles 5 added to the precoat film 3 can be prevented from falling off in the washing step. Moreover, the film 3 excellent in chemical resistance, heat resistance and hydrolyzability can be obtained. As a result, dissolution, peeling, discoloration, sticking, etc. of the film 3 in the boiling chlorine-based cleaning agent can be prevented. . In order to improve these effects, the gel fraction is desirably 65% or more. Furthermore, if the gel fraction is 75% or more, chemical resistance, heat resistance, hydrolyzability, durability of the film in the cleaning process, and the like are further increased, which is more desirable. In addition, since it is thought that a gel fraction is so large that it is so preferable, the upper limit of a gel fraction does not need to prescribe | regulate in particular. In order to set the gel fraction to 50% or more, it is desirable that the baking temperature when baking the coating film is about 150 to 285 ° C.

The gel fraction can be measured by a method according to JIS K6796 (however, the extraction solvent is not xylene but 2-butanone). That is, the test material of the precoated aluminum plate 1 is immersed for 60 minutes in boiling 2-butanone (MEK), and the change in mass of the precoated aluminum plate 1 before and after immersion is measured. Thereafter, the mass change of only the precoat film 3 is calculated by measuring the mass of the aluminum plate 2 in which only the precoat film 3 is completely dissolved, and it is assumed that the component that has not eluted into the MEK has undergone a crosslinking reaction. The ratio is calculated as a gel fraction.

[Surface roughness of precoat film]
The surface of the precoat film 3 needs to be formed so that the surface roughness is 0.25 μm or more in terms of arithmetic average roughness (Ra). A feature of the precoated aluminum plate 1 of the present invention is that the precoat film 3 is not dissolved, peeled, discolored, or stuck even in a cleaning process using a boiling chlorine-based cleaning agent. About the adhesion between each other, the surface roughness between the coatings 3 facing each other greatly affects. That is, when the surface roughness Ra is less than 0.25 μm, the surface of the film 3 becomes smooth. Therefore, when the films 3 face each other and are washed with a boiling chlorine-based cleaning agent, a slight tackiness between the films 3 is slight. (tackiness) begins to occur. Furthermore, when the surface roughness Ra is less than 0.15 μm, the surface of the precoat film 3 becomes smoother. Therefore, when the films 3 face each other and are washed with a boiling chlorine-based cleaning agent, the films 3 are strongly bonded to each other. It sticks. As described above, the adhesion between the coatings 3 in the cleaning process is greatly related to the smoothness of the surface of the precoat coating 3, and the larger the surface roughness Ra, the more the contact between the coating surfaces when viewed microscopically. Since the area is small, the sticking between the coatings 3 is suppressed.

Since it is considered that the larger the surface roughness Ra is, the higher the surface roughness Ra is, from the viewpoint of suppressing the adhesion between the coating films 3, the upper limit value of the surface roughness Ra does not need to be specified. However, when the surface roughness Ra is increased, visible light is likely to be irregularly reflected on the surface of the coating 3, and the surface of the coating 3 has a matte appearance. The surface roughness Ra of the precoat film 3 is 0.55 μm or less in order to suppress the appearance of the film 3 from being matted and to not disturb the beautiful glossy appearance of the aluminum plate 2 as a material. It is desirable that The surface roughness Ra can be controlled by appropriately adjusting the particle diameter, blending ratio, film thickness and the like of the fine particles 5. The surface roughness of the precoat film 3 is measured using, for example, a surface roughness measuring device (Surfcoder SE-30D manufactured by Kosaka Laboratory Ltd.), and the direction of the probe perpendicular to the rolling direction of each aluminum plate 2. And measuring the arithmetic average roughness (Ra) described in JIS B0601.

[Others]
The precoat film 3 can contain a colorant and additives imparting various functions without departing from the scope of the present invention.
For example, in order to further improve moldability, for example, lubrication of polyethylene wax, carnauba wax, microcrystalline wax, lanolin, TEFLON (registered trademark) wax, silicone wax, graphite lubricant, molybdenum lubricant, etc. One or more agents can be added. In addition, in order to provide conductivity for the purpose of securing the earth required by electronic devices, etc., as the conductive fine particles, for example, metal fine particles including nickel fine particles, metal oxide fine particles, conductive carbon, graphite, etc. 1 type (s) or 2 or more types can be added. Furthermore, when it is desired to improve heat dissipation, one or more heat dissipation additives such as metal oxides such as carbon, graphite, and titanium oxide, and ceramic powder can be added. And when antifouling property is requested | required, you may add a fluorine-type compound and a silicone type compound.
As will be described later, the thickness of the precoat film 3 is preferably 1 to 20 μm from the viewpoint of workability and productivity.

Although the best embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be changed without departing from the scope of the present invention.
For example, a surface treatment film (not shown) may be provided on the surface of the aluminum plate 2 by surface treatment.

<Pretreatment>
The surface of the aluminum plate 2 is preferably subjected to a ground treatment in order to improve the adhesion with the precoat film 3. As a desirable base treatment, a conventionally known reactive type base coat and coating type base coat containing Cr, Zr or Ti can be used. That is, a phosphoric acid chromate film, a chromate chromate film, a zirconium phosphate film, a zirconium oxide film, a titanium phosphate film, a coating type chromate film, a coating type zirconium film, and the like can be used as appropriate. Organic-inorganic hybrid-type ground treatment coatings obtained by combining these coatings with organic components may also be used. In recent years, there has been a tendency to dislike hexavalent chromium from the trend of environmental measures, and phosphate chromate films that do not contain hexavalent chromium, zirconium phosphate films, zirconium oxide films, titanium phosphate films, coated zirconium films, etc. It is desirable to use it.

In the present invention, as the film thickness of the base treatment film, the amount of Cr, Zr or Ti contained in the base treatment film component to the aluminum plate 2 (metal Cr, metal Zr or metal Ti equivalent value) is, for example, Since the conventional fluorescent X-ray method can be used for comparatively simple and quantitative measurement, the quality control of the precoated aluminum plate 1 can be performed without hindering productivity. The adhesion amount of the base treatment film is preferably 10 to 50 mg / m ² in terms of metal Cr, metal Zr or metal Ti. If the adhesion amount is less than 10 mg / m ² , the entire surface of the aluminum plate 2 cannot be uniformly coated, and the corrosion resistance is lowered. Moreover, when it exceeds 50 mg / m < ² >, when the precoat aluminum plate 1 is shape | molded, it will become easy to produce a crack in the membrane | film | coat itself of a surface treatment.

If productivity is not taken into consideration, the surface of the aluminum plate 2 can be subjected to a conventionally known treatment such as anodizing treatment or electrolytic etching treatment. When these treatments are performed, fine irregularities are formed on the surface of the aluminum plate 2, so that the adhesion of the precoat film 3 is greatly improved.

Furthermore, when it is desired to use a simple method without requiring much corrosion resistance, a method of only degreasing the surface of the aluminum plate 2 may be used. As a method of degreasing, conventionally known methods such as degreasing with an organic drug, degreasing with a surfactant drug, degreasing with an alkaline drug, degreasing with an acid drug, and the like can be used. However, in the case of organic chemicals and surfactant chemicals, the degreasing ability is slightly inferior, and therefore degreasing with an alkaline chemical or an acid chemical is more productive. The degreasing ability of alkaline chemicals can be controlled by the main component, concentration, and processing temperature of the alkali used.However, if the degreasing ability is increased, a lot of smut is generated, so that subsequent washing with water is sufficient. Otherwise, the adhesion of the precoat film 3 may be lowered. In addition, when a variety containing a large amount of magnesium as an additive element is used for the aluminum plate 2, magnesium may remain on the surface and the adhesion of the precoat film 3 may be reduced with an alkaline chemical. Therefore, in this case, it is desirable to use or use an acid drug.

≪Pre-coated aluminum sheet manufacturing method≫
Next, an example of the manufacturing method of the precoat aluminum plate 1 is demonstrated with reference to FIG. 1 suitably.
The method for producing the pre-coated aluminum plate 1 is not particularly limited, and a coating material containing a resin, a curing agent, and fine particles 5 as a base resin 4 is applied onto the aluminum plate 2 by a conventionally known method. Then, it can be obtained by causing a crosslinking reaction by heating. In order to set the gel fraction in the film 3 to 50% or more, it is desirable that the baking temperature when baking the paint is about 150 to 285 ° C.

Here, the coating may be applied by any means such as brush, roll coater, curtain flow coater, roller curtain coater, electrostatic coating machine, blade coater, die coater, etc. It is desirable to use a roll coater in which the coating amount is uniform and the operation is simple. When coating with a roll coater, the film thickness of the precoat film 3 is controlled by appropriately adjusting the conveyance speed of the aluminum plate 2, the rotation direction and rotation speed of the roll, the pressing pressure between the rolls (nip pressure), and the like. In general, the thickness of the coating 3 that can be applied by one coating operation is generally 1 to 20 μm. Therefore, the thickness of the precoat film 3 is desirably 1 to 20 μm in consideration of workability and productivity.

Second embodiment

≪Pre-coated aluminum plate≫
As shown in FIG. 1, a precoated aluminum plate 1 according to the present invention is a precoated aluminum plate 1 having a precoat film 3 formed on the (outermost) surface of an aluminum plate 2. The resin and the non-yellowing type isocyanate curing agent are composed of a thermosetting resin (base resin) 4 in which intermolecular crosslinking is performed, and the gel fraction is 70% or more and 92% or less. Although the fine particles 5 are not essential components (configuration) of the present invention, they are illustrated because they are preferably included in the precoat film 3. Here, the surface of the aluminum plate 2 means at least one surface of the aluminum plate 2. Each configuration will be described below.

<Aluminum plate>
Since it is the same as that of 1st Embodiment, description is abbreviate | omitted.

<Precoat film>
The precoat film 3 (film 3) comprises a thermosetting resin (base resin) 4 in which an epoxy resin (epoxy resin) and a non-yellowing type isocyanate curing agent are intermolecularly crosslinked, and the surface of the aluminum plate 2 Formed. The gel fraction of the precoat film 3 is 70% or more and 92% or less. In the base resin 4, a form containing fine particles 5 described later is desirable.

[Base resin]
The base resin (thermosetting resin) 4 is a main component of the precoat film 3, an epoxy resin (epoxy) as a main agent, and a non-yellowing type isocyanate curing agent (isocyanate (no yellowing) as a curing agent. )), And the intermolecular crosslinking reaction is performed so that the gel fraction is 70% or more and 92% or less. In addition, the mixing (blending) ratio of the epoxy resin and the non-yellowing type isocyanate curing agent is appropriately set depending on the type of the epoxy resin to be used.

There is a film laminate material that uses a thermoplastic resin as a base resin as a material that does not undergo intermolecular crosslinking by a thermosetting reaction. However, as described in the prior art, a material that uses a thermoplastic resin as a base resin is heat resistant. A problem arises. There is also a pre-coating material that uses a polyester-based thermosetting resin as a thermosetting resin with excellent drawability (processing), but as described in the above-mentioned prior art, it is also durable in a high-temperature and humid atmosphere. There are challenges. However, when a thermosetting resin obtained by using an epoxy resin and a non-yellowing type isocyanate curing agent and having an intermolecular cross-linking reaction at a predetermined gel fraction is selected as the base resin 4, this resin is originally intermolecular. Since it has a functional group for crosslinking, the adhesiveness with the aluminum plate 2 is excellent. Moreover, since the crosslinking reaction is carried out while controlling the gel fraction, chemical resistance and heat resistance are improved while maintaining drawability. Moreover, since it does not have an ester group that is easily hydrolyzed, durability under a high-temperature and humid atmosphere is also improved.

The epoxy resin (epoxy resin) used for the base resin 4 is a general term for resins having an epoxy group in which two carbon atoms and one oxygen atom are bonded in a triangular shape, and includes bisphenol A and epichlorohydrin. A typical example is a bisphenol A type epoxy resin having a repeating unit. In addition, bisphenol F type epoxy resin with reduced viscosity using bisphenol F instead of bisphenol A, a flame retardant epoxy resin obtained by reacting bisphenol A with bromine, a heat resistant epoxy resin based on a novolac resin, Alicyclic epoxy resins, etc. are known, and any epoxy resin of the present invention, including modified epoxy resins that have been chemically modified, may be used as long as it can be made into a paint. In view of the ease of coating, the balance between paint life and reactivity, price, safety, etc., it is preferable to use an epoxy resin having a basic skeleton of bisphenol A type or bisphenol F type or a modified product thereof.

Since the glass transition temperature is the same as that of the first embodiment, description thereof is omitted. However, in order to control (control) such a glass transition temperature, the above-described bisphenol A type or bisphenol F type is used as a basic skeleton, and a method of modifying the molecular structure by a chemical reaction is taken. Since there is no particular limitation on the modification method, the modified epoxy resin subjected to modification can be used freely.

Epoxy resin has a higher glass transition temperature than polyester resin. This is advantageous for ensuring heat resistance and the like. The glass transition temperature of the epoxy resin has been reported up to about 200 ° C., but if it is used for a precoat material premised on press molding, a glass transition temperature of 120 ° C. or higher is not very realistic ( Processability is reduced, and the shape that can be formed is limited). In the epoxy resin used in the present invention, the glass transition temperature is desirably 80 ° C. or lower. In addition, the glass transition temperature here means what was measured by DSC method.

Since the epoxy resin has an epoxy group, the epoxy group can be thermoset by a chemical reaction. Further, bisphenol A type and bisphenol F type epoxy resins have a hydroxyl group in the molecule in addition to the epoxy group. Therefore, by adding a curing agent that reacts with these functional groups (hydroxyl groups), or by modifying the epoxy resin using a chemical reaction so that a component that acts like a curing agent is generated in the epoxy resin itself. By doing, an epoxy resin can be heat-hardened (thermosetting reaction), and a thermosetting resin can be obtained.
As epoxy resin curing agents, phenolic curing agents and amine (urea, melamine) curing agents including urea (urea) and melamine are generally used. In the present invention, the non-yellowing type is used. The isocyanate curing agent is used. When a phenolic curing agent is used, the phenolic hydroxyl group of the phenolic compound is known to react with an epoxy group, and it is easy to obtain a soft film having a large network in which the ends of the epoxy resin have reacted. As a result, a film having excellent moldability can be obtained, but there are problems that phenol is easily yellowed and chemical resistance is inferior. When a urea-based curing agent is used, yellowing such as phenol can be avoided, but the obtained film is hard and it is difficult to obtain excellent moldability. Moreover, about melamine type hardening | curing agent, hardening reactivity is very low. As a method of improving the reactivity of this melamine curing agent, it is possible to use an acid catalyst together, but depending on the conditions, the curing reactivity may become too high, or it may turn yellow. difficult.

The isocyanate curing agent used in the present invention is a non-yellowing type. Isocyanates (compounds) are classified into toluene diisocyanate (TDI), methylene bisphenyl diisocyanate (MDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI) depending on the structure. being classified. The TDI system and the MDI system are easily yellowed (standard type), while the XDI system, the IPDI system, and the HDI system are hardly yellowed and are non-yellowing types. Polyisocyanates obtained by modifying these non-yellowing types with polyhydric alcohols are also included in the isocyanate curing agents that can be used in the present invention.

The non-yellowing type isocyanate curing agent is desirably a block type isocyanate compound. The block type here means that the active isocyanate group of the isocyanate compound is stabilized by a blocking agent such as an active hydrogen compound, and the reactivity is low at room temperature. This blocking isocyanate compound has reactivity due to dissociation of the blocking agent due to heating such as baking treatment, and regeneration of the active isocyanate group.
Blocking agents for blocked isocyanate groups include alcohols such as methanol, ethanol, n-propanol and tert-butanol, phenols such as phenol, m-cresol, isooctylphenol and resorcinol, ε-caprolactams, oximes, Examples include active methylene compounds such as acetylacetone, methyl ethyl ketone, and ethylene chlorohydrin, and sodium sulfite.

[Gel fraction of precoat film: 70% or more and 92% or less]
In the present invention, the gel fraction of the precoat film 3 is 70% or more and 92% or less. Here, when the precoat film 3 includes the fine particles 5 in the base resin 4, it is difficult to measure the gel fraction of the base resin 4 in a strict sense. Therefore, in the present invention, the gel fraction of the precoat film 3 is substituted and defined by this gel fraction.
When the gel fraction of the precoat film 3 is 70% or more, the crosslink density of the film 3 is increased, and the film 3 having excellent chemical resistance and heat resistance can be obtained. Moreover, since it can prevent that the film | membrane 3 hardens | cures too much if a gel fraction shall be 92% or less, the film | membrane 3 excellent in the drawability can be obtained. Furthermore, by setting the gel fraction of the film 3 to 85% or less, a further (further) excellent deep drawability can be obtained, which is more desirable. Thus, in order to make the gel fraction 70% or more and 92% or less, the baking temperature when baking the coating film is desirably about 200 to 285 ° C. in terms of the material reaching temperature.

The gel fraction can be measured by a conformable method according to JIS K6796 (however, the extraction solvent is not xylene but 2-butanone is used). That is, the specimen of the precoated aluminum plate 1 is dunk for 60 minutes in boiling 2-butanone (MEK), and the change in mass of the precoated aluminum plate 1 before and after immersion is measured. Thereafter, the mass change of only the precoat film 3 is calculated by measuring the mass of the aluminum plate 2 in which only the precoat film 3 is completely dissolved, and it is assumed that the component that has not eluted into the MEK has undergone a crosslinking reaction. The ratio is calculated as a gel fraction.

[Fine particles]
The fine particles 5 are for controlling the surface roughness Ra of the precoat film 3 in a predetermined manner, and are desirably contained in the base resin 4 of the precoat film 3.
Since the method for controlling the surface roughness without containing the fine particles 5 in the precoat film 3 is the same as in the first embodiment, the description thereof is omitted.

Since the type, form, size, addition amount, blending ratio, and particle size of the fine particles 5 are the same as those in the first embodiment, description thereof is omitted. Further, the crosslinked spherical organic fine particles constituting the fine particles are also the same as those in the first embodiment, and the description thereof is omitted.

[Surface roughness of precoat film]
The surface roughness of the precoat film 3 is the same as that of the first embodiment, and thus the description thereof will be omitted. However, in the cleaning process using the boiling chlorine-based cleaning agent, the adhesion between the precoat films 3 is the opposite film 3. The surface roughness between each other greatly affects.

[Others]
Since it is the same as that of 1st Embodiment, description is abbreviate | omitted.

<Pretreatment>
Since it is the same as that of 1st Embodiment, description is abbreviate | omitted.

≪Pre-coated aluminum sheet manufacturing method≫
Next, an example of the manufacturing method of the precoat aluminum plate 1 is demonstrated.
The manufacturing method of the precoated aluminum plate 1 is not particularly limited, and the resin (epoxy resin) that is the base of the base resin 4, the curing agent (non-yellowing type isocyanate curing agent), and preferably the fine particles 5 are added. The coating material to be contained can be obtained by applying a crosslinking reaction by heating after coating on the aluminum plate 2 by a conventionally known method. In order to set the gel fraction in the film 3 to 70% or more and 92% or less, it is desirable that the baking temperature when baking the paint is about 200 to 285 ° C.

Here, the application of the paint is the same as in the first embodiment, and thus the description thereof is omitted. However, it may be performed using a bar coater.

First embodiment

Next, the pre-coated aluminum plate of the present invention will be specifically described by comparing an example that satisfies the requirements of the present invention with a comparative example that does not satisfy the requirements of the present invention.

[First embodiment]
In the first example, the durability of the film in the cleaning step, which is an essential object of the present invention, was examined for the precoated aluminum plate in the present invention.

In the study of the precoated aluminum plate according to the present invention, the aluminum plate used as a material was a 0.3 mm thick material having an alloy number of A1100-H24. This was degreased with a weak alkaline degreasing agent, and then subjected to a phosphoric acid chromate treatment as a base treatment. The condition of the phosphoric acid chromate treatment was 20 mg / m ² in terms of chromium adhesion. The mechanical properties of the aluminum plate used were a tensile strength of 130 MPa, a proof stress of 120 MPa, and an elongation of 8%. Next, on one side of an aluminum plate that has been subjected to a phosphoric acid chromate treatment, a paint containing various resin-based paints shown in Tables 1 and 2 and fine particles shown in Table 1 is added so that the dry film thickness becomes 6 μm. After coating with a bar coater, a precoat film was formed by baking the paint so that the baking temperature was in the range of 150 to 285 ° C., and used as a test material. In addition, no. In No. 20, after the bar coater coating and baking are completed, a stainless steel surface plate with a surface roughness Ra of about 0.5 μm is layered on the coating surface, and lightly sandwiched for 10 minutes with a hot press heated at 40 ° C. As a result, the surface roughness of the surface plate was transferred.

Here, the base resin of the paint shown in Tables 1 and 2 is polyester melamine is a polyester resin blended with a melamine curing agent, polyester isocyanate is a polyester resin blended with an isocyanate curing agent, epoxy Urea is an epoxy resin blended with a urea curing agent, epoxy phenol is an epoxy resin blended with a phenol curing agent, and epoxy acrylic is an intramolecular cross-linked acrylic modified epoxy resin. is there. Further, the glass transition temperatures shown in Tables 1 and 2 are glass transition temperatures in the respective resins.

As for the fine particles shown in Tables 1 and 2, crosslinked acrylic beads and crosslinked urethane beads are crosslinked organic fine particles, nickel powder and talc powder are inorganic fine particles, and thermoplastic urethane beads and polystyrene latex are uncrosslinked organic fine particles. is there. The blending ratio was the mass% of the fine particles in the mass of the dry precoat film including the base resin and the fine particles.

For the specimens manufactured as described above, the gel fraction and surface roughness Ra of the precoat film were measured.

(Measurement of gel fraction)
A test material (piece) obtained by cutting the test material into 10 cm × 10 cm was used, and the gel fraction of the film was measured. After the test material was dried at 80 ° C. for 60 minutes, the initial mass (a) was measured, and then the test material was immersed in boiled MEK for 60 minutes to elute uncrosslinked components, and then 150 The remaining MEK in the film was dried at 60 ° C. for 60 minutes, and the mass (b) after extraction was measured. Finally, the film was completely dissolved in fuming nitric acid, and the mass (c) of the aluminum plate alone was measured. Here, since (a)-(c) is the mass of the original precoat film only, and (b)-(c) can be regarded as a crosslinked film mass, the gel fraction expressed by the following formula is It represents the degree of crosslinking.
(Gel fraction) = ((b)-(c) / (a)-(c)) × 100 (unit%)

(Measurement of surface roughness Ra)
The surface roughness of the precoat film is measured by using a surface roughness measuring instrument (Surfcoder SE-30D manufactured by Kosaka Laboratory Ltd.) and scanning the probe in a direction perpendicular to the rolling direction of each aluminum plate. The arithmetic average roughness (Ra) described in B0601 was measured.

Next, the durability of the film in the cleaning process, which is an essential object of the present invention (hereinafter referred to as “cleaning process durability”), was examined for the specimen.

(Washing process durability)
Trichrene was used as a chlorine-based cleaning agent and boiled. The coated surfaces of the test materials were sandwiched between clips so as to face each other, dipped in boiling tricyclen for 10 minutes, and then taken out to confirm the appearance. Those having no surface abnormality such as dissolution of the film, peeling of the film, discoloration of the film, and adhesion between the films were judged to have good cleaning process durability (◯) and those having surface abnormality to be defective (×).
These results are shown in Table 1. In Table 1, those not satisfying the configuration of the present invention are underlined, and those not containing fine particles are indicated by “−”.

As shown in Table 1, no. Nos. 1 to 16 satisfy the constitution of the present invention, and all of them were free from surface abnormalities such as dissolution of the film, peeling of the film, discoloration of the film, and adhesion between the films, and the cleaning process durability was good. .
On the other hand, no. No. 17 contained no fine particles, and the surface roughness did not satisfy the scope of the present invention, so that the films were stuck to each other (denoted as stuck in the table), and the cleaning process durability was poor. No. In No. 18, since the surface roughness did not satisfy the range of the present invention, the films were stuck to each other and the cleaning process durability was poor. No. No. 19, since the gel fraction of the film did not satisfy the scope of the present invention, the films adhered to each other and the color of the film changed to white (denoted as whitening in the table). No. No. 20, although the surface roughness satisfies the scope of the present invention before immersion in boiling trichrene, it does not contain fine particles, so the unevenness of the coating surface becomes smooth during immersion in boiling trichrene, Sticking occurred.

Thus, it can be seen that, if the configuration of the present invention is satisfied, a precoated aluminum plate having excellent durability of the coating film in the cleaning process is obtained.

[Second Embodiment]
In the second example, the drawability and appearance properties were examined in order to investigate a more desirable form of the precoated aluminum plate in the present invention. Since these characteristics are only desirable characteristics for the present invention, even if these characteristics are not satisfied, those satisfying the cleaning process durability of the first embodiment are the minimum of the present invention. The purpose is to reach.
Since the preparation method of the test material, the gel fraction of the precoat film, the measurement of the surface roughness Ra, and the like are the same as those in the first example, description thereof is omitted here.

(Drawing formability)
FIG. 2 is a schematic diagram showing a process for producing a bottomed cylindrical container by drawing and ironing a test material. The drawability of the test material was examined by the process shown in FIG. First, after blanking a cylindrical blank, drawing was performed. Next, a 12 mmφ × 15 mmL cylindrical drawn product (intermediate molded product) was obtained by redrawing. The result of evaluating the film state of the intermediate molded product obtained at this time was defined as shallow drawability in Table 2. Next, iron was added to the intermediate molded product so that the reduction rate of the thickness of the cylindrical side wall portion was 20%, trimmed and processed into a cylindrical container shape having a final 10 mmφ × 20 mmL to obtain a final molded product. The result of evaluating the film state of the final molded product obtained at this time was defined as deep drawability in Table 2. The press oil used was an aqueous emulsion wax mainly composed of a fatty acid ester and a surfactant. The processing was performed only at room temperature (35 ° C.).

The evaluation of the film state is that for the shallow drawability, when the precoat film is not peeled off from the aluminum plate, the shallow drawability is good (◯), and when it is peeled, the shallow drawability is poor (×). Judgment was made regarding the deep drawability, when the precoat film was not peeled off from the aluminum plate, the deep drawability was good (○), and when it was peeled, the deep drawability was judged as poor (×). . And both the shallow drawability and the deep drawability were judged to be good when the precoat film was not peeled off from the aluminum plate. Moreover, although the shallow drawability was good, it was judged that the drawability was slightly inferior for those having poor deep drawability.

(Appearance properties)
The appearance of the precoat film after bar coating and baking was visually observed. When the matte state, unevenness, yellow discoloration, etc. did not occur, the appearance properties were judged as good (◯). In addition, if any of these occurred, the appearance properties were judged to be slightly inferior, and in Table 2, those with strong matting properties (whether matting was strong or not) The matte property was described as “matte △”, the product with unevenness (uneven), the “smooth ×”, and the product with slightly yellowish discoloration as “yellow discoloration Δ”. Here, the appearance property is based on the beautiful gloss appearance of the aluminum plate as a material, and is a standard different from the discoloration of the film in the cleaning process durability.
These results are shown in Table 2. In Table 2, those not satisfying the preferred configuration of the present invention are underlined, and those not containing fine particles are indicated by “−”.

(Drawing formability)
As shown in Table 2, no. Nos. 1 to 7 and 9 to 13 had better drawability because more desirable base resins were used. On the other hand, no. In No. 8, since the glass transition temperature of the polyester resin was too high, the shallow drawability was good, but the deep drawability was poor and the drawability was slightly inferior. No. 14, no. Since No. 15 used an epoxy resin, the shallow drawability was good, but the deep drawability was poor and the drawability was slightly inferior. No. No. 16 used an intramolecular cross-linked acrylic modified epoxy resin, and although the shallow drawability was good, the deep drawability was poor and the drawability was slightly inferior.

(Appearance properties)
As shown in Table 2, no. Nos. 1, 3, 4, 6 to 9, 12, 14, and 16 have a desirable surface roughness because the surface roughness of the film is in a desirable range and more desirable fine particles are used. . On the other hand, no. 2, no. 5, no. 10, no. 11, no. Since the surface roughness of the film 13 was not in a desirable range, the appearance was strong or slightly strong. No. No. 11 used organic fine particles that were not crosslinked as fine particles, so that the surface roughness varied depending on the location, and the appearance was uneven as a whole. In addition, No. No. 15 uses epoxy phenol, but when epoxy phenol is used, yellowing of the film tends to occur. In No. 15, the appearance of the film turned yellow.

As described above, it can be seen that a more desirable configuration within the range satisfying the configuration of the present invention results in a precoated aluminum plate having excellent formability and appearance properties in addition to excellent durability of the film in the cleaning process. .

Although clear data has not been obtained this time, when inorganic fine particles are used as the fine particles, the convex portions of the precoat film become hard, and it is sufficiently expected to reduce the life of the press molding die. Similarly, when the particle shape is spherical, the shape of the convex portion of the precoat film is smooth when viewed microscopically, so there is no irrationality in considering that the influence on the mold life is small.

From the above results, in the precoated aluminum plate, the precoat film formed on the surface of the aluminum plate contains a base resin cross-linked between the molecules and fine particles, and the gel fraction of the precoat film is 50% or more, By using a thermosetting resin, which is the object of the present invention, with a surface roughness Ra of 0.25 μm or more, a precoated aluminum plate excellent in the durability of the film in a cleaning process in a boiling chlorine-based cleaning agent and You can see that you can.
Furthermore, it can be seen that by using a more desirable base resin, it is possible to obtain a precoated aluminum plate having high formability comparable to that of the film laminate material in addition to the achievement of the object. Further, by using more desirable fine particles and setting the surface roughness Ra in a more desirable range, in addition to achieving the above object, a precoated aluminum plate that does not interfere with the beautiful gloss appearance of the aluminum plate that is the material is used. You can see that

Second embodiment

[First embodiment]
In the first embodiment, the pre-coated aluminum plate of the present invention has the essential purpose (essential performance) of the present invention, durability in a high-temperature wet environment (high-temperature wet durability), chemical resistance, heat discoloration resistance, aperture The moldability was examined.

In the examination of the pre-coated aluminum plate according to the present invention, the aluminum plate used as a material is the same as that in the first embodiment, and the description thereof is omitted. However, a coating material in which various main agents (resin system) shown in Table 3 and various curing agents are blended on one side of an aluminum plate subjected to phosphoric acid chromate treatment is applied to a bar coater (bar coater) so that the dry film thickness becomes 6 μm. After coating, a precoat film having a changed gel fraction was formed by baking the paint so that the baking temperature was in the range of 150 to 285 ° C., and used as a test material. Moreover, the glass transition temperature shown in Table 3 is a glass transition temperature in each said resin system.

The gel fraction of the precoat film was measured for the specimen prepared as described above.

(Measurement of gel fraction)
Since it is the same as that of 1st Embodiment, description is abbreviate | omitted.

Next, each test material was examined for durability under a high temperature wet environment (high temperature wet durability), chemical resistance, heat discoloration resistance, and drawability, which are essential objects of the present invention.

(High temperature wet (environmental) durability)
A flat plate test material cut out from the test material was used and left in a constant temperature and humidity chamber set to a temperature of 85 ° C. and a humidity of 85% RH for 1000 hours, and then the appearance of the film was visually confirmed. As a result, a film having no abnormalities was evaluated as good (◯), and a film having abnormal appearance such as discoloration, peeling, swelling, and cracking was defined as an abnormal appearance (×).

(chemical resistance)
A flat test material cut out from the test material was used, immersed in cyclic ester γ-butyllactone at room temperature for 10 minutes, and the appearance of the film was visually confirmed. As a result, a film having no abnormalities was evaluated as good (◯), and a film having abnormal appearance such as discoloration, peeling, swelling, and cracking was defined as an abnormal appearance (×).

(Heat-resistant discoloration)
A flat test material cut out from the test material was used and left in a box-type heating tank set at a temperature of 270 ° C. for 1 minute, and then the appearance of the film was visually confirmed. As a result, a film having no abnormalities was evaluated as good (◯), and a film having abnormal appearance such as discoloration, peeling, swelling, and cracking was defined as an abnormal appearance (×).

(Drawing formability)
FIG. 2 is a schematic diagram showing a process for producing a bottomed cylindrical container by drawing and ironing a test material. The drawability of the test material was examined by the process shown in FIG. First, drawing was performed after cylindrical blank punching (blanking). Next, a 12 mmφ × 15 mmL cylindrical drawn product (intermediate molded product) was obtained by redrawing. The result of evaluating the film state of the intermediate molded product obtained at this time was defined as shallow drawability in Table 3. Next, the intermediate molded product was ironed so that the reduction rate of the thickness of the cylindrical side wall portion was 20%, trimmed, and processed into a final 10 mmφ × 20 mmL cylindrical container shape to obtain the final molded product. . The result of evaluating the film state of the final molded product obtained at this time was defined as the deep drawability in Table 3. The press oil used was an aqueous emulsion wax mainly composed of a fatty acid ester and a surfactant. The processing was performed at room temperature (35 ° C.).

For the evaluation of the film state, the shallow drawability, which is an essential performance of the present invention, is that when the precoat film is not peeled off from the aluminum plate, the shallow drawability is good (O), and when the peel is peeled off, the shallow drawability is formed. Judgment was poor (×). In addition, only the specimens that had good shallow drawability (O) were confirmed to have the desired deep drawing formability. As a result, the precoat film was not peeled off from the aluminum plate and the deep drawability was good. In the case where it was present, the moldability was particularly good (◎), and when it was peeled off, it was regarded as defective (Δ).

Table 3 shows the results of durability (high temperature wet durability), chemical resistance, heat discoloration resistance, and drawability in a high temperature wet environment. In addition, the underline in Table 3 indicates that the requirements defined in the present invention are not satisfied.

(High temperature wet (environmental) durability)
As shown in Table 3, a polyester resin was used as the resin system of the base resin. In all of Nos. 17 to 22, abnormalities such as whitening, cracking, and swelling occurred in the appearance of the film. Among the test materials using an epoxy resin as the resin system of the base resin, No. 1 using a melamine-based curing agent as the curing agent. In No. 10, the coating melted and the appearance was abnormal. In addition, this No. No. 10 had a gel fraction of 0, and the epoxy resin and the melamine meter curing agent did not react at all. Each of the test materials other than the above seven types had good durability in a high temperature and humid environment.
From the above, in order to ensure durability in a high-temperature and humid environment, the main agent (resin system) used for the base resin needs to be an epoxy resin. Moreover, since it is necessary to react to some extent with a hardening | curing agent, a melamine type hardening | curing agent is not suitable as a hardening | curing agent.

(chemical resistance)
As shown in Table 3, the gel fraction of the base resin was less than 70%, No. As for 5, 7, 10, 11, 13, 15, 17, 19, and 21, all abnormalities such as whitening and dissolution occurred in the appearance of the film. Further, among the test materials having a gel fraction of 70% or more, No. 1 in which an epoxy resin and a phenolic curing agent were reacted. In No. 14, whitening occurred in the appearance of the film. Each of the test materials other than the above 10 types had good chemical resistance.
From the above, in order to ensure chemical resistance, the gel fraction of the film (base resin) needs to satisfy 70% or more. Also, phenolic curing agents are not suitable as curing agents.

(Heat-resistant discoloration)
As shown in Table 3, a phenolic curing agent was used as the curing agent. Nos. 13 and 14 and a standard type isocyanate curing agent that is not a non-yellowing type were used as curing agents. For No. 9, yellowing of the film was observed. Each of the sample materials other than the above three types had good heat discoloration.
From the above, it is important to select a curing agent in order to ensure heat discoloration, and a phenolic curing agent is not suitable, and when the curing agent is an isocyanate curing agent, no yellowing occurs. It is necessary to select the type.

(Drawing formability)
As shown in Table 3, in each test material in which an epoxy resin and an isocyanate curing agent (non-yellowing) were combined, the gel fraction exceeded 92%. For 6 and 8, film peeling occurred. In addition, no. For 11 and 12, film peeling occurred. In addition, the acrylic modified self-processed epoxy resin also has a high gel fraction. For 16, peeling of the film occurred. Each of the test materials other than the above five types had good shallow drawability.
From the above, the drawability (shallow drawability) is affected by the type (combination) of the main resin (system) and the curing agent, and the crosslinking reaction between the main agent (resin system) and the curing agent. It turns out that the influence of the gel fraction which shows a grade is also large. In particular, when the main agent (resin type) is an epoxy resin and the curing agent is an isocyanate type curing agent (no yellowing), it is important that the gel fraction is 92% or less. Also, urea curing agents are not suitable as the curing agent.

Next, the deep drawability (working) property was confirmed about each test material with favorable shallow drawability. As shown in Table 3, with respect to each test material in which an epoxy resin and an isocyanate curing agent (no yellowing) are combined, the gel fraction exceeds 85%. In 2 and 4, the film peeled off during deep drawing (test). In addition, No. of acrylic modified self-crosslinking epoxy resin. 15 and No. 15 using polyester resin. No. 22 was peeled off in the deep drawing test. As a result, it was No. which combined the epoxy resin and the isocyanate curing agent that satisfied the deep drawability. Nos. 1, 3, 5, 7, and 9 were combined with an epoxy resin and a melamine curing agent. No. 10, a combination of epoxy resin and phenolic curing agent. No. 13 and No. 14 using polyester resin. There were a total of 13 types of 5 types from 17 to 21.
In particular, when the main agent (resin) is an epoxy resin and the curing agent is an isocyanate curing agent (no yellowing), excellent deep drawability is obtained when the gel fraction is 85% or less. I understood it.

(Summary)
As shown in Table 3, those that satisfy all four essential performances of durability under high temperature and humidity (high temperature wet durability), chemical resistance, heat discoloration resistance, and drawability (shallow drawability) , No. There were four types of 1-4.
Therefore, as a constitution of the precoat film of the precoat aluminum plate, the epoxy resin and the non-yellowing type isocyanate curing agent are combined and reacted so that the gel fraction becomes 70% or more and 92% or less. Then it turned out to be essential.
Further, No. 1 which satisfies the deep drawing formability, which is a desirable performance. 1 and No. The composition of the pre-coated aluminum plate is a combination of an epoxy resin and a non-yellowing type isocyanate curing agent, and reacts so that the gel fraction is 70% or more and 85% or less. It has been found desirable in the present invention.

[Second Embodiment]
In the second example, the paint life, which is a desirable object of the present invention, was examined for a paint containing an epoxy resin and a non-yellowing type isocyanate curing agent used when producing the precoated aluminum plate in the present invention. In addition, since the paint life is only a desirable characteristic for the present invention, even if these characteristics are not satisfied, those satisfying the results of the first embodiment can achieve the minimum object of the present invention. It is.

Mixing block type isocyanate curing agent or non-blocking type isocyanate curing agent with commercially available bisphenol A type or bisphenol F type epoxy resin (including modified epoxy resin), diluting solvent for viscosity adjustment As a sample material, a paint was prepared by mixing toluene.
The mixing ratio of the epoxy resin and the isocyanate curing agent was fixed at a ratio of 5: 1 in terms of solid content weight. The viscosity adjusting diluent was adjusted so that the initial viscosity immediately after the bath was # 4 Ford cup viscosity of 100 seconds (within ± 5 seconds).

(Paint life)
The test material paint thus prepared (initial make-up of electrolytic bath) was placed in a sealed container and stored at room temperature for 7 days and 3 months. (Paint life) was determined. Here, if the viscosity of the paint (ford cup) is within 150 seconds, it was judged that there was a lifetime.

Table 4 shows the results for paint life. In addition, the underline in Table 4 indicates that the requirements defined in the present invention are not satisfied.

(Paint life)
As shown in Table 4, sample No. using a non-blocking type as the isocyanate curing agent. In 1, 3, 5, 7, and 9, all were solidified so that the viscosity of the paint could not be measured after 7 days, and the paint life was not sufficient. On the other hand, the test material No. using a block type isocyanate curing agent. 2, 4, 6, 8, and 10 all showed a slight increase (in seconds) at the stage after 3 months, and it was found to be reusable.

[Third embodiment]
In the third example, the durability of the precoated aluminum plate was investigated in order to investigate a more desirable form of the precoated aluminum plate in the present invention. The durability of the cleaning process is only a desirable characteristic for the present invention. Therefore, even if these characteristics are not satisfied, those satisfying the results of the first embodiment are the minimum object of the present invention. To reach.

The type, quality, mechanical properties of the aluminum plate used as the material, the pretreatment method and the conditions before coating are the same as in the first embodiment. A coating containing various fine particles (particle type, particle diameter μm) shown in Table 5 on a base resin made of an epoxy resin having a glass transition temperature of 77 ° C. and a non-yellowing type isocyanate curing agent on this aluminum plate was dried. After coating with a bar coater so as to be 6 μm, a precoat film was formed by baking so that the gel fraction was 80 ± 5%, and used as a test material.
In addition, No. 11 and no. No. 13 is a test material not containing fine particles. No. 13, after the bar coater coating and baking were completed, a stainless steel surface plate with a surface roughness Ra of about 0.5 μm was layered on the coated surface, and lightly sandwiched with a hot press heated at 40 ° C. for 10 minutes. The surface roughness of the board was transferred.
Further, for the fine particles shown in Table 5, crosslinked acrylic (bead) and crosslinked urethane (bead) are crosslinked organic fine particles, nickel powder and talc powder are inorganic fine particles, and thermoplastic urethane (beads) are not crosslinked. Organic fine particles. The blending ratio was the mass% of the fine particles in the mass of the dry precoat film including the base resin and the fine particles.

For the specimens manufactured as described above, the gel fraction and surface roughness Ra of the precoat film were measured. The method for measuring the gel fraction was the same as in the first example.

(Measurement of surface roughness Ra)
As for the surface roughness of the precoat film, a surface roughness measuring device (Surfcoder SE-30D manufactured by Kosaka Laboratory Co., Ltd.) was used, and the probe was scanned in a direction perpendicular to the rolling direction of each aluminum plate. JIS B0601 The arithmetic average roughness (Ra) described in 1 was measured.

Next, the test material was examined for film durability (cleaning process durability) at the time of boiling tricyclene cleaning, which is a desirable object of the present invention, and other appearance properties.

(Washing process durability)
Trichrene was used as a chlorine-based cleaning agent and boiled. The coated surfaces of each test material were sandwiched between clips so as to face each other, immersed in the boiling trichrene for 10 minutes, and then taken out to confirm the appearance. A film having no surface abnormality such as dissolution, peeling, discoloration, and adhesion between films was judged to be defective (x) if it had good cleaning process durability (◯) and surface abnormality (such as adhesion).

(Appearance properties)
The appearance of the precoat film after bar coating and baking was visually observed. When the matte state, unevenness, yellow discoloration, etc. did not occur, the appearance properties were judged as good (◯). Moreover, it was judged that the appearance property was slightly inferior (x) when any of these occurred.

Table 5 shows the results of cleaning process durability and appearance properties. In addition, the underline in Table 5 indicates that the requirements defined in the present invention are not satisfied.

(Washing process durability)
As shown in Table 5, no. In all of Nos. 1 to 10, since the surface roughness Ra was set to 0.25 μm or more by adding fine particles into the film, the cleaning process durability was good.
On the other hand, no. No. 11 contained no fine particles, and the surface roughness did not satisfy the scope of the present invention, so that the films were stuck together, and the durability of the cleaning process was poor. No. In No. 12, since the surface roughness did not satisfy the range of the present invention, the films were stuck to each other, and the durability of the cleaning process was poor. No. No. 13, although the surface roughness satisfies the scope of the present invention before immersion in boiling trichrene, since it does not contain fine particles, the unevenness of the coating surface becomes smooth during immersion in boiling trichrene, and the coatings stick to each other. occured.

(Appearance properties)
No. with good washing process durability. Nos. 1 to 10 are organic fine particles in which the fine particles are not crosslinked. No. 8 had a non-uniform appearance (non-uniform appearance) because the fine particles melted in the baking process after bar coater coating. In addition, this No. 8 and no. In the five types 2, 5, 7, and 10, the surface roughness Ra exceeded 0.55 μm, so the matteness of the film was strong (matte) and the luster of the aluminum material was impaired.

The precoated aluminum plate according to the present invention has been described in detail with reference to the best mode and examples, but the gist of the present invention is not limited to the above-described contents, and the scope of the right is claimed. Must be interpreted based on the description. Needless to say, the contents of the present invention can be modified and changed based on the above description.

Claims

A precoated aluminum plate having a precoat film formed on the surface of the aluminum plate,
The precoat film is composed of a base resin cross-linked between molecules and fine particles,
The precoat film has a gel fraction of 50% or more and a surface roughness of 0.25 μm or more in terms of arithmetic average roughness (Ra).
2. The precoated aluminum plate according to claim 1, wherein the fine particles are crosslinked organic fine particles.
3. The precoated aluminum plate according to claim 2, wherein the fine particles are spherical.
2. The precoated aluminum plate according to claim 1, wherein the base resin is a crosslinked polyester obtained by crosslinking a polyester resin having a glass transition temperature of 25 to 65 ° C. with a melamine curing agent or an isocyanate curing agent. A precoated aluminum plate, which is a resin.
2. The precoated aluminum plate according to claim 1, wherein the polyester resin has a glass transition temperature of 35 to 60 ° C.
2. The precoated aluminum plate according to claim 1, wherein the surface roughness of the precoat film is an arithmetic average roughness (Ra) of 0.25 to 0.55 μm.
2. The precoated aluminum plate according to claim 1, wherein the proportion of the fine particles in the precoat film is 1 to 50% by mass.
2. The precoated aluminum plate according to claim 1, wherein the fine particles have a particle diameter of 1 to 50 μm.
2. The precoated aluminum plate according to claim 1, wherein the precoat film has a thickness of 1 to 20 μm.
A precoated aluminum plate having a precoated film formed on the surface of the aluminum plate,
The precoat film is composed of a thermosetting resin in which an epoxy resin and a non-yellowing type isocyanate curing agent are intermolecularly crosslinked,
The precoated aluminum plate, wherein the gel fraction of the precoat film is 70% or more and 92% or less.
The precoated aluminum plate according to claim 10, wherein the gel fraction of the precoated film is 70% or more and 85% or less.
11. The precoated aluminum plate according to claim 10, wherein the non-yellowing type isocyanate curing agent is a block type isocyanate compound.
The precoated aluminum plate according to claim 10, wherein the precoat film includes inorganic fine particles or fine particles which are crosslinked organic fine particles in the thermosetting resin serving as a base resin, and has a surface roughness. The arithmetic average roughness (Ra) is 0.25 μm or more, and a pre-coated aluminum plate.
14. The precoated aluminum plate according to claim 13, wherein the fine particles are cross-linked spherical organic fine particles.
14. The precoated aluminum plate according to claim 13, wherein the surface roughness of the precoat film is an arithmetic average roughness (Ra) of 0.25 to 0.55 μm.