JP2011173277A - Precoated aluminum sheet for electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precoated aluminum sheet for an electronic device which has excellent conductivity, lubricity, fingerprint-proof property and corrosion resistance and is friendly in environment. <P>SOLUTION: The precoated aluminum sheet 10 is obtained by forming a resin coating film 12 without providing a substrate treatment coating film containing chromium on at least one surface of an aluminum base sheet 11 having 0.3 to 0.5 μm arithmetic mean roughness Ra. The resin coating film 12 does not contain a metal element and contains an acrylic resin component, an urethane resin component, a silica component and a particulate lubricating component, wherein the content of the silica component occupied in the resin coating film 12 is >12 mass%, the content of the lubricating component contained in the resin coating film 12 is >8 mass%, the average film thickness of the resin coating film 12 is 0.15 to 1.0 μm and resistance measured by a specific method is ≤10 Ω. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a precoated aluminum plate that is molded and used as a case or a structural member of an electronic device.

  Aluminum plates (including aluminum alloy plates) have high strength and formability, and can be significantly reduced in weight compared to steel plates. Therefore, containers, foils, electrical products, automobile supplies, Furthermore, it is applied to various uses such as building materials.

  The molded product of the aluminum plate may be subjected to surface treatment for the purpose of improving the appearance and corrosion resistance in accordance with the intended use and environment. Here, as a method for performing the surface treatment, from the viewpoint of mass productivity, simplification of the manufacturing process, cost reduction, etc., a precoated aluminum plate in which a film is formed by performing a surface treatment on the aluminum plate before press forming is used. The precoat method is desirable.

  Furthermore, in recent years, such pre-coated aluminum sheets have various functions such as fingerprint resistance, scratch resistance, electrical conductivity (ground connection), heat dissipation, and thermal insulation in order to meet the diversification and upgrading of products and equipment. Functional pre-coated aluminum plates imparted with antibacterial, antifungal, hydrophilic, water repellency, lubricity, etc. have been developed and are widely used. Among these, precoated aluminum plates having electrical conductivity, fingerprint resistance, scratch resistance and lubricity are most widely used as precoated aluminum plates for electronic devices.

In Patent Document 1, an aluminum plate is coated with a resin containing a lubricant to form a resin film, thereby making fingerprints attached to the surface and fine wrinkles generated on the surface inconspicuous. A surface-treated aluminum plate excellent in scratching has been proposed.
According to the present invention, although the fingerprint resistance and wrinkle resistance of the aluminum plate are improved to some extent, the surface of the aluminum plate coated with the resin film serving as an insulator exhibits insulation properties. In the case where the ground is taken from the case or the structural member, a post-process such as providing a conducting portion by removing a part of the resin film and exposing a metal portion of the aluminum plate is required.

  Therefore, in order to solve the problem of ensuring conductivity on the surface of such a pre-coated aluminum plate, techniques for coating a resin film containing a conductive substance have been proposed in Patent Document 2 and Patent Document 3.

  However, in the method of coating the surface of the aluminum plate with the resin containing the conductive material in this way, it is necessary to uniformly disperse the particles of the conductive material in the resin, and it is formed on the surface of the aluminum plate. In the case where the contact between the particles of the conductive material is not sufficiently ensured in the formed resin film, or when the contact between the conductive material and the aluminum plate is not sufficiently ensured at the interface between the resin film and the aluminum plate, There arises a problem that desired conductivity cannot be obtained. Therefore, in order to obtain the desired conductivity, it is necessary to increase the component amount of the conductive material. However, if the amount of the conductive material component is increased, the resin film becomes hard and brittle, so that the resin film is likely to be cracked (peeled) when it is pressed on the aluminum plate on which the resin film is formed. Problems arise.

  In order to solve the problems of the invention in which the conductive material is added to the resin film, the present inventors pay attention to the relationship between the surface roughness of the aluminum plate and the average film thickness of the resin film in Patent Document 4. In addition, we are proposing a technology to ensure conductivity without using conductive materials. That is, in Patent Document 4, as shown in FIG. 5, a predetermined corrosion-resistant film 42 and a resin film having a predetermined average film thickness are formed on at least one surface of an aluminum base plate 41 having a predetermined centerline average roughness Ra. 43, and a pre-coated aluminum plate 40 for an electronic device is described in which the fine irregularities of the aluminum base plate 41 are exposed on the surface of the resin film 43 in a state of being covered with the corrosion-resistant film 42. In this way, other requirements are satisfied while improving high conductivity.

  The pre-coated aluminum plate for electronic equipment described in Patent Document 4 having the above-described structure is excellent in conductivity, fingerprint resistance, wrinkle resistance, and lubricity. Therefore, the cover of the optical disk drive, the frame of the liquid crystal panel, the liquid crystal It is used in various electronic devices such as the back panel of panels and the inner case of in-vehicle audio.

Japanese Patent Publication No. 6-70870 JP 7-313930 A Japanese Patent No. 3245696 Japanese Patent No. 4237975

  However, the corrosion-resistant film used in the precoated aluminum plate for electronic devices described in Patent Document 4 is a conventionally known corrosion-resistant film mainly composed of chromium (Cr) or zirconium (Zr), and the corrosion-resistant film is Cr. Patent Document 4 describes that a phosphoric acid chromate-treated film, a chromic acid chromate-treated film, a coating-type chromate-treated film, or the like can be used as appropriate.

  For example, the phosphate chromate treatment for forming a phosphate chromate treatment film is a treatment in which a chemical solution having hexavalent chromium and aluminum are chemically reacted, and hexavalent chromium is reduced to trivalent in the course of the reaction. The resulting chemical conversion film (corrosion resistance film) is known as a treatment not containing hexavalent chromium. In addition, the reaction solution containing hexavalent chromium used in chemicals has a so-called “closed system” design that does not allow wastewater or waste to flow out of the equipment, including the washing water. It is well known that this is a completed technology.

However, from the point of view of general consumers, it is difficult to think that the difference between trivalent chromium and hexavalent chromium is correctly understood, and the sound of the word “chromium” itself may reduce the image of the product. .
In recent years, in the field of electronic equipment, from the viewpoint of environmental protection, “EU Directive on Restriction of Use of Specific Hazardous Substances in Electronic and Electrical Equipment (RoHS Directive)” and “EU Directive on Waste Electrical and Electronic Products (WEEE Directive)” etc. Therefore, the raw material used is in a direction to be restricted, and hexavalent chromium corresponds to this.

As described above, the phosphate chromate-treated film does not contain hexavalent chromium, but contains trivalent chromium. If this is used as a product and discarded, it is no longer possible to control what kind of environment it will be exposed to after disposal. For this reason, it is difficult to say that there is no possibility that trivalent chromium is transformed into hexavalent chromium in a special environment.
In order to reach 100% from the safety of hexavalent chromium by stepping up to such a level, there is no other way than ensuring the predetermined performance without using chromium at all.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a chromium-containing ground treatment film typified by phosphoric acid chromate as well as excellent conductivity, lubricity, fingerprint resistance and wrinkle resistance. An object of the present invention is to provide an environment-friendly precoated aluminum plate for electronic equipment that has excellent corrosion resistance without being formed at all.

  The pre-coated aluminum plate for electronic equipment according to the present invention that has solved the above problems is provided with an undercoat film containing chromium on at least one surface of an aluminum base plate having an arithmetic average roughness Ra of 0.3 μm or more and 0.5 μm or less. A pre-coated aluminum plate for an electronic device on which a resin film is formed, wherein the resin film does not include a metal element, and includes an acrylic resin component, a urethane resin component, a silica component, and a particulate lubricating component, The content of the silica component in the resin film exceeds 12% by mass, the content of the lubricating component contained in the resin film exceeds 8% by mass, and the average film thickness of the resin film is 0.15 μm or more. A spherical terminal having a radius of 10 mm at a tip of 0 μm or less is pressed against the aluminum base plate on which the resin film is formed with a load of 0.4 N. It is characterized in that the resistance value between the aluminum workpieces and the spherical terminal is 10Ω or less at the time (claim 1).

The pre-coated aluminum plate for electronic equipment according to the present invention does not form a chromium-containing ground treatment film, and regulates the arithmetic average roughness Ra of the aluminum base plate and the average film thickness of the resin film within specific ranges, respectively. Therefore, the fine protrusions of the aluminum base plate protruded higher than the average height of the resin film, and the film thickness of the resin film covering the protrusions was almost the same as that of the case of forming the ground treatment film of the prior art. Stay around. Therefore, excellent conductivity can be ensured such that the resistance value measured by the above method is 10Ω or less.
In addition, the precoated aluminum plate for electronic equipment according to the present invention defines the resin component for forming the resin film as described above, and includes a silica component and a lubricating component having a predetermined content as essential components, thereby providing electronic equipment. As well as ensuring the corrosion resistance required for use, lubricity, fingerprint resistance and scratch resistance are ensured. Furthermore, since the resin film does not contain a base treatment film containing chromium and does not contain chromium or other metal elements, an environment-friendly pre-coated aluminum plate for electronic devices is realized.

In the precoated aluminum plate for electronic equipment according to the present invention, it is preferable that no base treatment film is provided between the aluminum base plate and the resin film.
Thus, if it is set as the structure which does not provide any base-treatment film including the base-treatment film which does not contain chromium between an aluminum base plate and a resin film, it will be used for the process of forming a base-treatment film, and a base-treatment film formation. Since a chemical | medical agent is abbreviate | omitted, the equipment structure which manufactures the precoat aluminum plate for electronic devices of this invention can be simplified significantly, the precoat aluminum plate for electrical devices which can be reduced in cost and productivity was embodied.

In the precoated aluminum plate for electronic equipment according to the present invention, the particle diameter of the lubricating component contained in the resin film is preferably 2.5 μm or less.
In this way, even when the film thickness of the resin film formed on the precoated aluminum plate for electronic equipment according to the present invention is reduced to the vicinity of the lower limit, the lubricating component does not easily fall off, so that high conductivity is achieved. A pre-coated aluminum plate for electronic equipment that maintains a higher lubricity while maintaining it is realized.

The resin film of the precoated aluminum plate for electronic equipment according to the present invention preferably further contains 1% by mass to 30% by mass of optical property adjusting fine particles having an average particle size of 0.3 μm or more and 15 μm or less (Claim 4). .
In this way, a pre-coated aluminum plate for electronic equipment with further improved fingerprint resistance by further optimizing the optical characteristics of the surface is realized.

In the precoated aluminum plate for electronic equipment according to the present invention, the chromium content as an alloying additive element contained in the aluminum base plate is preferably less than 0.1% by mass (Claim 5).
In this way, since not only the resin film and the base treatment film but also the aluminum plate itself does not contain chromium, a pre-coated aluminum plate for electronic equipment that is more environmentally friendly can be realized.

According to the pre-coated aluminum plate for electronic equipment according to the present invention, the arithmetic average roughness Ra of the aluminum base plate and the average film thickness of the resin film are regulated within specific ranges, respectively, and further the components of the resin film are optimized. Therefore, it has excellent conductivity, lubricity, fingerprint resistance, scratch resistance and corrosion resistance.
Moreover, according to the precoat aluminum plate for electronic devices which concerns on this invention, since a resin film and a base-treatment film do not contain chromium, it is environmentally friendly.

It is a principal part expanded sectional view which shows typically the structure of the precoat aluminum plate for electronic devices which concerns on this invention. It is a schematic diagram which shows typically the method of measuring the resistance value of the precoat aluminum plate for electronic devices. It is a principal part expanded sectional view which shows typically the structure of the other example of the precoat aluminum plate for electronic devices which concerns on this invention. It is a schematic diagram which shows typically the shear bending test method which measures the abrasion resistance of the precoat aluminum plate for electronic devices. It is a principal part expanded sectional view which shows typically the structure of the precoat aluminum plate for electronic devices which concerns on a prior art.

Hereinafter, the precoated aluminum plate for electronic equipment according to the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, the precoat aluminum plate 10 for electronic devices which concerns on this invention has the aluminum base plate 11 and the resin film 12 formed in the at least single side | surface of this aluminum base plate 11. As shown in FIG. In addition, between this aluminum base plate 11 and the resin film 12, the chemical conversion film (base-treatment film | membrane) containing chromium like the phosphoric acid chromate used at least generally is not formed. However, as shown in FIG. 3, it is permissible to form this between the aluminum base plate 11 and the resin film 12 if it is a base treatment film that does not contain chromium.

The resin film 12 formed on the surface of the aluminum base plate 11 does not contain a metal element, includes an acrylic resin component, a urethane resin component, a silica component, and a particulate lubricating component. The content exceeds 12% by mass, and the content of the lubricating component contained in the resin film 12 exceeds 8% by mass.
In addition, since the fine unevenness | corrugation is formed in the surface of the aluminum base plate 11, the above-mentioned resin film 12 is formed relatively thick about the uneven | corrugated recessed part of the surface of the aluminum base plate 11, and about a convex part, It is formed relatively thin, and the average film thickness is 0.15 μm or more and 1.0 μm or less.
Since the precoated aluminum plate 10 for electronic equipment according to the present invention has such a resin film 12, a spherical terminal 23 (see FIG. 2) having a radius of 10 mm at the tip is formed of an aluminum element on which the resin film 12 is formed. When pressed against the plate 11 with a load of 0.4 N, the resistance value between the spherical terminal 23 and the aluminum base plate 11 can be 10Ω or less.

  In addition, the description regarding the precoat aluminum plate 10 for electronic devices which concerns on the above-mentioned this invention, the structure of the precoat aluminum plate 10 for electronic devices which concerns on this invention shown in FIG. 1, and the precoat for electronic devices which concerns on the prior art shown in FIG. As can be seen from a comparison with the configuration of the aluminum plate 40, the resin film 12 of the precoat aluminum plate 10 for electronic equipment according to the present invention is the corrosion resistant film 42 and the resin film 43 of the precoat aluminum plate 40 for electronic equipment according to the prior art. And has a unified structure and role. Therefore, as will be described in detail later, it is not hindered to provide the base treatment film 13 not containing chromium as shown in FIG.

  Hereinafter, each structural requirement of the precoat aluminum plate 10 for electronic devices which concerns on this invention is demonstrated.

[Aluminum base plate]
The aluminum base plate 11 that can be used in the present invention is made of aluminum or an aluminum alloy, and the type that can be used is not particularly limited, and is based on the product shape, molding method, strength required at the time of use, and the like. Can be arbitrarily selected. In general, a non-heat-treatable 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 ironing, aluminum plates such as A1050, A1100, A3003, and A3004 defined in JISH4000 are recommended. Further, when a relatively shallow container-shaped case is manufactured or when a case mainly made of bending is manufactured, aluminum plates such as A5052 and A5182 defined in JISH4000 are recommended. Various types of tempering and plate thickness can be selected and used according to the purpose.

  In addition, it is most preferable that the aluminum base plate 11 does not contain chromium, but when it contains chromium, the content is preferably less than 0.1% by mass. The reason specified in this way is not a problem in performance, but in order to make the product more friendly to the environment, it does not actively add chromium except for chromium components inevitably mixed with recycled metal. This is to stand in a position. Moreover, if this level of chromium content is not allowed, not only the excellent recyclability that is an advantage of aluminum alloys is impaired, but only new bullion can be used every time, so a great deal of energy and resources are required. On the contrary, it becomes a product that is not environmentally friendly.

  From this point of view, among the above-described aluminum alloys, A5052 has a chromium content of 0.15 to 0.35 mass% in the alloy, and chromium must be positively added as an alloy component. Corresponds to alloys that must not be. The use of such an alloy is not desirable for the present invention, so it is desirable to use an alternative alloy with similar performance if possible. For example, as an alternative alloy of A5052, 5K52 (contains about 2.5 mass% magnesium equivalent to A5052, does not actively contain chromium, and adds about 0.45 mass% manganese instead of chromium. Kobe Steel Co., Ltd.) can be used for the aluminum base plate.

(Arithmetic average roughness Ra of aluminum base plate: 0.3 μm or more and 0.5 μm or less)
The arithmetic average roughness Ra of the aluminum base plate 11 includes various properties such as conductivity, corrosion resistance, fingerprint resistance, and scratch resistance in the precoated aluminum plate 10 for electronic equipment of the present invention, as well as the average film thickness of the resin film 12 to be described later. It is an important parameter that contributes to the development of properties.

When the arithmetic average roughness Ra of the aluminum base plate 11 is less than 0.3 μm, the glossiness of the surface of the precoated aluminum plate 10 for electronic equipment becomes excessively large, and fingerprints adhering to the surface and the fineness generated on the surface A wrinkle becomes conspicuous, and is inferior to fingerprint resistance and wrinkle resistance. Further, in this case, the height of the convex portion of the base of the aluminum base plate 11 having fine irregularities described above is lowered, and as a result, the film thickness of the resin film 12 covering the convex portion is increased, so that the desired conductive It is difficult to ensure the property.
On the other hand, when the arithmetic average roughness Ra of the aluminum base plate 11 exceeds 0.5 μm, the height of the convex portion of the aluminum base plate 11 becomes too high, so that the top of the convex portion is easily exposed from the resin film 12. As a result, since the exposed surface of the aluminum base plate 11 is worn by the mold, the scratch resistance is lowered and the lubricity is also lowered. Moreover, if a convex part is exposed from the resin film 12, corrosion will generate | occur | produce from there and will spread to circumference | surroundings, and corrosion resistance will fall.
That is, by defining the arithmetic average roughness Ra of the aluminum base plate 11 in the range of 0.3 μm or more and 0.5 μm or less, it is possible to provide excellent conductivity, fingerprint resistance, scratch resistance and corrosion resistance. .

  In addition, as a method of adjusting the arithmetic average roughness Ra of the aluminum base plate 11 within the above-described range, for example, cold rolling is performed using a rolling roll whose surface roughness is appropriately set in the rolling process of the aluminum base plate 11. The final (finishing) rolling method, the method of etching the surface of the aluminum base plate 11 after the rolling under appropriate conditions, the blasting method of hitting fine particles, and the like.

  In the present invention, the aluminum base plate is formed on the aluminum base plate 11 in which the arithmetic average roughness Ra is adjusted in this way and the fine irregularities are formed, so that the resin film 12 specifying the components and the average film thickness is formed. The film thickness of the resin film 12 covering the 11 minute projections does not become too thick and does not become too thin. Therefore, it is possible to obtain the precoated aluminum plate 10 for electronic equipment that has the desired conductivity, lubricity, fingerprint resistance, and wrinkle resistance, and has improved corrosion resistance.

  In addition, it is permissible to form this between the aluminum base plate 11 and the resin film 12 as long as it does not contain chromium. However, if no ground treatment film is formed, a ground treatment film is formed. Since the chemicals used for forming the process and the base treatment film can be omitted, it is possible to greatly simplify the equipment configuration for producing the precoated aluminum plate 10 for electronic equipment of the present invention, and to reduce the cost. Productivity can be increased.

[Resin film]
(Constituent components of resin film: including acrylic resin component, urethane resin component, silica component and particulate lubricating component)
As described above, the resin film 12 used in the precoated aluminum plate 10 for electronic equipment of the present invention needs to contain an acrylic resin component, a urethane resin component, a silica component, and a particulate lubricating component as constituent components.

  Since the acrylic resin component and the urethane resin component are used in combination as the resin component, not only the concave portions on the surface of the aluminum base plate 11 having fine irregularities but also the convex portions can be covered with a thin film. Thus, the precoated aluminum plate 10 having good fingerprint resistance can be obtained.

  Here, the content ratio of the acrylic resin component and the urethane resin component in only the resin component is a mass ratio, and the acrylic resin component: urethane resin component is preferably 5:95 to 95: 5, and more preferably 10:90 to 90: 10 and more desirably 50:50 to 85:15. When the acrylic resin component is larger than 95: 5, the corrosion resistance is inferior. On the other hand, when the urethane resin component is larger than 5:95, the corrosion resistance and the scratch resistance become inferior.

  As described above, the silica component and the lubricating component are dispersed in the resin component using both the acrylic resin component and the urethane resin component, and as described above, not only the recesses on the surface of the aluminum base plate 11 having fine unevenness, but also the protrusions are thinly and uniformly covered. Therefore, compared with resin films using other resin components, the effect of improving the corrosion resistance and lubricity is great. In particular, since the effect of improving the corrosion resistance is remarkably increased, for example, a base treatment film 42 such as a phosphate chromate treatment film that has been imparted with corrosion resistance by the conventional precoated aluminum plate 40 for electronic equipment (see FIG. 5) is used. Even if it is thin film thickness (average film thickness) like this invention, high corrosion resistance can be ensured now.

(Resin film component: Does not contain metal elements)
The present invention aims to provide an environmentally friendly pre-coated aluminum plate 10 for electronic equipment, so that a base treatment film containing chromium is not provided, but other metal elements as well as chromium are contained in the resin film 12. By not including it, the precoat aluminum plate 10 for electronic devices that is more environmentally friendly can be provided. For example, as a rust preventive pigment (rust preventive pigment) often added for the purpose of improving the corrosion resistance, there are a lead rust preventive pigment, a zinc rust preventive pigment, and a phosphoric acid rust preventive pigment. Examples of lead-based anticorrosive pigments include red lead, lead suboxide, basic lead chromate, lead cyanamide, calcium leadate, and basic lead sulfate, and contain Pb, Cr, and Ca. Zinc-based rust preventive pigments contain Zn, and phosphoric acid-based rust preventive pigments include zinc phosphate, magnesium phosphate, sodium polyphosphate, zinc calcium phosphate, aluminum tripolyphosphate, and aluminum phosphomolybdate. Zn, Mg, Na, K, Al, and Mo are contained. In addition, as coloring pigments that are often added for the purpose of coloring, there are white pigments such as titanium oxide, zinc oxide pigments, iron oxide pigments, etc., but these contain Ti, Zn, Fe, The extender pigment includes calcium carbonate, barium sulfate, alumina, kaolin, talc, bentonite, mica, and the like, and contains Ca, Ba, Al, Mg, and Na. Furthermore, there are nickel powder, aluminum powder, stainless steel powder, zinc powder, cadmium yellow, cobalt violet, molybdate orange, etc. as conductive paints. These include Ni, Al, Fe, Zn, Cd, Co, and Mo. Contained.
Therefore, the resin film 12 must not contain rust preventive pigments, colored pigments, and conductive paints containing these metal elements. However, as will be described later, the resin film 12 does not contain corrosion resistance and conductivity. However, since sufficient performance can be exhibited, there is no problem with not containing them.

(Silica component content in the resin film: more than 12% by mass)
The silica component dramatically improves the corrosion resistance. Therefore, by containing this in excess of a certain amount, it becomes possible to provide the precoated aluminum plate 10 for electronic equipment with corrosion resistance that cannot be obtained with only the acrylic resin component and the urethane resin component.
When the content of the silica component is 12% by mass or less, the corrosion resistance decreases. Therefore, the corrosion resistance is reduced as compared with the conventional pre-coated aluminum plate 40 (see FIG. 5) for electronic equipment using a chromium-containing base treatment film (corrosion-resistant film 42 (see FIG. 5)) such as a phosphate chromate-treated film. End up. The content of the silica component is preferably 15% by mass or more.
Further, considering the fluidity of the resin during coating, the content of the silica component is preferably 50% by mass or less.

(Lubricating component content in resin film: more than 8% by mass)
As the name suggests, the lubricating component plays a role of improving lubricity and improving moldability.
When the content of the lubricating component is 8% by mass or less, sufficient lubricity cannot be obtained. Therefore, the amount of generated abrasion powder increases during continuous pressing, and the resin film is easily peeled off. Cause a malfunction. Therefore, the content of the lubricating component needs to exceed 8% by mass. The content of the lubricating component is desirably 12% by mass or more.
Moreover, since the film forming property of the resin film tends to be lowered and the scratch resistance tends to be lowered when the content of the lubricating component is increased, the content of the lubricating component is desirably 30% by mass or less.

(Preferred particle size of lubricating component: 2.5 μm or less)
As described above, the lubricating component is in the form of particles. The particle size is desirably 2.5 μm or less. When the particle diameter of the lubricating component exceeds 2.5 μm, the lubricating component easily falls off the resin film when the average film thickness defined in the present invention is near the lower limit. The particle diameter of the lubricating component used in the present invention is more preferably 0.6 μm or less. In order to enhance the lubricity and effectively exert the effect of improving the moldability, the particle size of the lubricating component is desirably 0.1 μm or more.

  As a lubricating component, for example, polyethylene wax, polyalkylene wax, microcrystalline wax, fluorine wax, lanolin wax, carnauba wax, paraffin wax, graphite, from the viewpoint of appropriately balancing moldability improvement and economy. At least one selected from among them can be used.

(Desired component: optical property adjusting fine particles)
In the precoated aluminum plate 10 for electronic equipment of the present invention, it is desirable to add optical property adjusting fine particles. In the present invention, since it contains fine particles such as silica component and lubricating component, it originally has excellent fingerprint resistance. However, by adding optical property adjusting fine particles, the optical properties of the surface are further optimized and fingerprint resistance is improved. The precoat aluminum plate 10 for electronic devices with further improved properties can be realized.

  Examples of such optical property adjusting fine particles include various organic fine particles such as acrylic resin fine particles, nylon resin fine particles, urethane resin fine particles, polyolefin resin fine particles, fluororesin fine particles, and glass fine particles. At least one selected from inorganic fine particles such as, for example, can be used.

(Preferred particle size of optical property adjusting fine particles: 0.3 μm to 15 μm)
When the optical property adjusting fine particles are added, the particle size of the optical property adjusting fine particles is preferably 0.3 μm or more and 15 μm or less. If the particle size of the optical property adjusting fine particles is less than 0.3 μm, the effect of improving the optical property is hardly obtained, so there is no point in adding this. On the other hand, when the particle diameter of the optical property adjusting fine particles exceeds 15 μm, the fine particles easily fall off from the resin film 12. Since the lower the chemical activity, such as fluororesin beads and polyolefin resin beads, the easier it is to drop from the resin film 12, the particle diameter is more preferably 5 μm or less. Further, assuming that the average film thickness defined in the present invention is near the lower limit, the particle diameter is more preferably 2.5 μm or less.

(A desirable component amount of the optical property adjusting fine particles: 1% by mass or more and 30% by mass or less)
In addition, when the optical property adjusting fine particles are added, the component amount of the optical property adjusting fine particles is preferably 1% by mass or more and 30% by mass or less. If the component amount of the optical property adjusting fine particles is less than 1% by mass, the effect of improving the optical property is hardly obtained, so there is no point in adding this. On the other hand, when the component amount of the optical property adjusting fine particles exceeds 30% by mass, the number of the fine particles in the resin film 12 becomes too large, so that the fine particles are formed between the electrode and the aluminum base plate 11 when securing conductivity. In order to prevent the two from approaching each other in between, the conductivity decreases. Therefore, the component amount of the optical property adjusting fine particles is more preferably 10% by mass or less.

(Average film thickness of resin film: 0.15 μm to 1.0 μm)
The resin film 12 formed on the aluminum base plate 11 is provided for imparting desired lubricity, corrosion resistance, fingerprint resistance and wrinkle resistance to the precoated aluminum plate 10 for electronic equipment according to the present invention. It is. In the present invention, by defining the average film thickness of the resin film 12 within a specific range of 0.15 μm or more and 1.0 μm or less, the desired conductivity can be obtained in addition to lubricity, corrosion resistance, fingerprint resistance, and scratch resistance. Is embodied.

If the average film thickness of the resin film 12 is less than 0.15 μm, the convex portions of the aluminum base plate 11 cannot be sufficiently covered, so that sufficient corrosion resistance may not be obtained. In addition, since the resin film 12 formed in the concave portion of the aluminum base plate 11 is thin, the silica component and the lubricating component are also reduced, and therefore, the fingerprint resistance and wrinkle resistance are inferior, and the lubricity is not sufficient. The molding process becomes difficult.
On the other hand, if the average film thickness of the resin film 12 exceeds 1.0 μm, the aluminum element 11 may be roughened so that the surface roughness (arithmetic average roughness Ra) of the aluminum base plate 11 is close to the upper limit defined in the present invention. Since the resin film 12 covering the convex portion of the plate 11 is too thick, it is difficult to ensure desired conductivity.

(Method for forming resin film)
For example, the resin film 12 is formed by continuously applying a liquid film-forming agent containing the resin component defined in the present invention to one or both surfaces of the coiled aluminum base plate 11 by a roll coating method, It can be formed by passing through a continuous oven formed in a single or plural series and baking. In this way, the precoated aluminum plate 10 for electronic equipment can be manufactured continuously and quickly, which is preferable in terms of productivity.
At this time, since the resin film 12 is initially in a liquid state when applied on the surface of the aluminum base plate 11, the resin film 12 covers the convex portions on the surface of the aluminum base plate 11 while being preferentially filled into the concave portions. Cover the recesses thickly. Then, a hard resin film 12 having a thin film thickness is formed on the convex portion by a baking process performed subsequently, and a hard resin film 12 having a thick film thickness is formed on the concave portion. It can be made to have a film thickness.
The average film thickness of the resin film 12 can be determined relatively easily from the area of the portion where the resin film 12 is formed and the amount of the resin.

[Performance of pre-coated aluminum sheet for electronic equipment]
(Resistance value: 10Ω or less)
In the precoated aluminum plate 10 for electronic equipment according to the present invention, it is necessary that the resistance value measured by a method as described later be 10Ω or less. If the resistance value is 10Ω or less, it is possible to ground directly from the resin film 12 of the precoated aluminum plate 10 for electronic equipment. Moreover, electromagnetic wave noise can be sufficiently removed. Therefore, when the electronic device is a drive device such as an optical disk drive, and the precoated aluminum plate 10 for electronic device according to the present invention is used for a structural member such as a case and a chassis of the drive device, a writing or reproduction error is induced. When the electronic device is a liquid crystal panel and the precoated aluminum plate 10 for an electronic device according to the present invention is used as a structural member such as a fixing frame and a back cover of the liquid crystal panel, image noise is generated. It becomes difficult.
On the other hand, if the resistance value exceeds 10Ω, it is impossible to ground directly from the resin film 12 and to sufficiently remove electromagnetic noise.

  In the present invention, the arithmetic average roughness Ra of the aluminum base plate 11 is set within a specific range (0.3 μm or more and 0.5 μm or less) defined in the present invention, and the average film thickness of the resin film 12 is defined in the present invention. By making it within a specific range (0.15 μm or more and 1.0 μm or less), the resistance value measured by a specific method is set to 10Ω or less. That is, in the pre-coated aluminum plate 10 for electronic equipment according to the present invention, the aluminum base plate is formed by appropriately forming the resin film 12 on the aluminum base plate 11 having the arithmetic average roughness Ra within a specific range. 11 fine convex portions protruded higher than the average height of the resin film 12. Thus, in the convex part which protruded higher than the average height of the resin film 12, the film thickness of the resin film 12 is substantially the same as that of the conventional coating ground treatment film (corrosion resistant film 42 (see FIG. 5)). Since the thickness remains, the resistance value can be 10Ω or less, and the conductivity can be ensured.

However, the arithmetic average roughness Ra of the aluminum base plate 11 is within a specific range (0.3 μm or more and 0.5 μm or less) and the average film thickness of the resin film 12 is within a specific range (0.05 μm or more and 1.0 μm or less). However, even if it is a necessary condition for satisfying the condition that the resistance value is 10Ω or less, it is not a sufficient condition. Even if these conditions are satisfied, the resistance value may not be 10Ω or less. For example, when the arithmetic average roughness Ra of the aluminum base plate 11 is near the lower limit and the average film thickness of the resin film 12 is near the upper limit, the unevenness of the aluminum base plate 11 is small and the film thickness is large. It is easy to become.
Therefore, the present invention requires that the resistance value measured by a specific method described later is 10Ω or less.

As a specific example, Comparative Example C3 of Japanese Patent Application Laid-Open No. 2004-68042 describes an example in which an aluminum alloy plate having a surface roughness of 0.4 μm is used and a coating is applied by 0.62 μm.
This satisfies the requirements of the present invention for both the surface roughness Ra of the aluminum base plate 11 and the coating amount (average film thickness) of the coating film, but the resistance value is 23Ω and does not satisfy the requirements of the present invention. . Although it is necessary to consider the influence of the difference in measurement method, in Comparative Example C3, the load when measuring the resistance value is 100 g, and the electrode is applied with a force stronger than 0.4 N (≈40 gf) of the present application. Since it is pressed against the test piece, the measurement method should measure a lower resistance value than the method specified in the present invention, but only a high resistance value that does not satisfy the requirements of the present invention can be obtained. Results are disclosed.
As can be seen from this example, the arithmetic average roughness Ra of the aluminum base plate 11 is within the range of 0.3 μm to 0.5 μm and the average film thickness of the resin film 12 is 0.15 μm to 1.0 μm. In the present invention, since it is not a sufficient condition even if it is a necessary condition for satisfying the requirement that the resistance value measured by a specific method described below is 10 Ω or less, it is determined by the specific method described later in the present invention. Only those that have been confirmed to satisfy the requirement that the measured resistance value is 10Ω or less are considered as the present invention.

FIG. 2 is a diagram schematically showing a method of measuring the resistance value of the precoated aluminum plate for electronic equipment according to the present invention. This measurement method is a measurement method using the same method and the same conditions as those disclosed in Patent Document 4, Japanese Patent Application Laid-Open No. 2005-297290, Japanese Patent Application Laid-Open No. 2002-206178, and the like.
The resistance value measuring method in the present invention is such that one terminal 21 of the tester 20 is in direct conductive contact with an aluminum base plate exposed by polishing a part of a resin film of a pre-coated aluminum plate for electronic equipment with sandpaper, The other terminal 22 of the tester 20 is passed through a brass spherical terminal 23 whose tip is formed in a substantially spherical shape with a radius of 10 mm from the top of the resin film of the pre-coated aluminum plate for electronic equipment to the measurement location at 0.4 N ( Measured by a one-point contact method performed by contacting with a load of ≈40 gf). Note that the terminal 21 of the tester 20 (the terminal opposite to the spherical terminal 23) must be in direct contact with the aluminum base plate of the pre-coated aluminum plate for electronic equipment, so it is in direct contact with the portion where the resin film is polished and removed with sandpaper or the like. Let Further, since the natural oxide films on the surfaces of the terminal 21 and the spherical terminal 23 also cause variations in the measured resistance value, the surfaces of the terminal 21 and the spherical terminal 23 are previously sandpaper or the like before measuring the resistance value. It is desirable to sufficiently remove the natural oxide film by polishing with. Further, in order to eliminate the influence of the internal resistance of the tester 20 at the time of measuring the resistance value, before the resistance value is measured, the tip of the terminal 21 and the tip of the spherical terminal 23 are brought into contact with each other. It is desirable to perform point correction, use the most sensitive range of the tester 20, and use the value when the display of the tester 20 is stabilized as the measurement value. In order to sufficiently ensure the reliability of the resistance value, the measurement of the resistance value is measured at a random position at least 10 places, preferably 50 places, for one electronic device pre-coated aluminum plate, It is desirable to adopt the average value as the resistance value defined in the present invention.

[Undercoat film]
The role of the base treatment film formed on a general pre-coated aluminum plate is to improve the corrosion resistance while improving the adhesion between the resin film and the aluminum base plate. For this purpose, an inorganic single film or an inorganic / organic composite film containing Cr or Zr is often used. Of these, a trivalent chromium phosphate chromate-treated film is often used as a base-treated film. However, since the resin film 12 of the present invention has the role of the ground treatment film as described above, it is not always necessary to provide the ground treatment film. One of the objects of the present invention is to provide an environmentally friendly pre-coated aluminum plate 10 for electronic equipment, and in particular, a conventionally known phosphoric acid chromate-treated film, chromate-chromated film, and coating-type chromate-treated film. It is unacceptable to provide a base treatment film containing chromium. Therefore, when a base treatment film is formed in order to further improve the adhesion between the resin film 12 and the aluminum base plate 11 and the corrosion resistance, it is allowed to form the base treatment film if it does not contain chromium. be able to.

In the case of forming a base treatment film not containing chromium, the precoated aluminum plate 10 ′ for electronic equipment according to the present invention has a configuration as shown in FIG. 3, for example.
As shown in FIG. 3, the precoat aluminum plate 10 ′ for electronic equipment includes an aluminum base plate 11, a resin film 12 formed on at least one surface of the aluminum base plate 11, and a space between the aluminum base plate 11 and the resin film 12. Thus, a base treatment film 13 containing no chromium is formed.

  Examples of such a base treatment film 13 include a zirconium phosphate (PZr) treatment film and a titanium phosphate (PTi) treatment film. Of course, it is needless to say that the ground treatment film 13 should not contain environmentally hazardous substances other than chromium, for example, substances whose use is restricted by RoHS or WEEE.

The pre-coated aluminum plate 10 for an electronic device according to the present invention described above can be understood as follows.
The precoated aluminum plate 10 for an electronic device according to the present invention is a precoated aluminum for an electronic device in which a resin film 12 is formed on at least one surface of an aluminum base plate 11 having a center line average roughness Ra of 0.3 μm or more and 0.5 μm or less. A base treatment film (corresponding to the corrosion-resistant film 42 in FIG. 5) is not formed between the aluminum base plate 11 and the resin film 12, and the resin film 12 does not contain a metal element and is an acrylic resin. Component, urethane resin component, silica component, and particulate lubricant component, the silica component content in the resin film 12 exceeds 12 mass%, and the lubricant component content in the resin film 12 is 8 mass% %, The average film thickness of the resin film 12 is 0.15 μm or more and 1.0 μm or less, and the spherical terminal 23 (see FIG. 2) having a radius of 10 mm at the tip portion Resistance of at 10Ω or less between the spherical terminal 23 and the aluminum workpiece 11 at the time when pressed with a load of 0.4N with respect to the aluminum workpieces 11 formed a film 12 (see FIG. 1).
It is also possible to provide a base treatment film 13 (see FIG. 4) that does not contain chromium between the aluminum base plate 11 and the resin film 12.

According to the precoat aluminum plate 10 for electronic devices which concerns on this invention demonstrated above, there exist the following effects.
(1) According to the pre-coated aluminum plate 10 for electronic equipment according to the present invention, the arithmetic average roughness Ra of the aluminum base plate 11 and the average film thickness of the resin film 12 are specified within a specific range, and the resin component, silica component The content and the content of lubricating components were defined. Thereby, the convex part of the aluminum base plate 11 having fine irregularities protrudes higher than the average height of the resin film 12, and the film thickness of the resin film 12 covering the convex part is the coating surface treatment of the prior art. The film is almost the same as the film (corrosion-resistant film 42 (see FIG. 5)), and the conductivity, fingerprint resistance, and scratch resistance can be maintained at the same level as in the prior art. In particular, by defining the resin component of the resin film 12 as a specific one, excellent corrosion resistance can be ensured without forming a base treatment film containing chromium (corrosion resistance film 42 (see FIG. 5)). . Moreover, since the base-treatment film | membrane containing chromium is not formed, the precoat aluminum plate 10 for electronic devices of this invention is more environmentally friendly than the precoat aluminum plate for electronic devices of a prior art.

(2) According to the pre-coated aluminum plate 10 for electronic equipment according to the present invention, the base including the base treatment film not containing chromium as well as the base treatment film containing chromium is provided between the aluminum base plate 11 and the resin film 12. Since no treatment film is provided, the step of forming the base treatment film and the chemical used for the formation of the base treatment film can be omitted, so that the equipment configuration for producing the precoated aluminum plate 10 for electronic equipment of the present invention is provided. It can be greatly simplified, cost can be reduced and productivity can be increased.

(3) According to the precoated aluminum plate 10 for electronic equipment according to the present invention, since the particle diameter of the lubricating component contained in the resin film 12 is 2.5 μm or less, the film thickness of the resin film 12 is Even when it is near the lower limit of the above-described range, it is possible to make it difficult for the lubricating component to fall off, so it is possible to ensure higher lubricity while maintaining high conductivity.

(4) According to the precoated aluminum plate 10 for electronic equipment according to the present invention, the resin film 12 contains 1% by mass to 30% by mass of optical property adjusting fine particles having an average particle size of 0.3 μm to 15 μm. Therefore, the optical characteristics of the surface can be further optimized and the fingerprint resistance can be further improved.

(5) According to the precoat aluminum plate 10 for electronic equipment according to the present invention, the aluminum base plate 11 used for the precoat aluminum plate has a chromium content of 0.001 as an additive element for alloy contained in the aluminum base plate 11. Since it is less than 1% by mass, it can be made more environmentally friendly.

The precoat aluminum plate 10 for an electronic device according to the present invention can be suitably used for various electronic device cases and structural members such as a case and chassis of an optical disk drive device, a fixing frame for a liquid crystal panel, and a back cover.
Furthermore, since the precoated aluminum plate 10 for electronic equipment according to the present invention has excellent lubricity, it is excellent in formability, and quality defects occur in press molding in the process of producing a molded article for electronic equipment. The rate can be reduced and the product yield can be improved. Thereby, this invention can reduce the whole cost of the molded article for electronic devices, As a result, it contributes greatly to the cost reduction of electronic device products.

  Next, the precoated aluminum plate for electronic devices according to the present invention will be described more specifically by comparing an example that satisfies the requirements defined in the present invention with a comparative example that does not satisfy the requirements.

Precoated aluminum plates of Examples 1 to 23 and Comparative Examples 1 to 14 were produced as follows.
First, an aluminum ingot having a composition of A5182 defined in JISH4000 was melted and the alloy components were adjusted, and then a slab for rolling was manufactured by casting. The segregation layer on the surface of the slab is chamfered and subjected to a homogenization process, followed by a hot rolling process, a cold rolling process, and a heat treatment process to obtain an aluminum base plate (plate thickness: 0.5 mm, alloy type: A5182- H34) was produced. In the final (finishing) step of the cold rolling, an aluminum element having various surface roughnesses (arithmetic average roughness) shown in Tables 1 and 2 by appropriately changing the surface roughness of the rolling rolls. A board was produced.

  Then, the manufactured aluminum base plate was degreased using the commercially available weak alkaline degreasing liquid for aluminum, and it was set as the coating pretreatment. Next, as shown in Tables 1 and 2, the base treatment using zirconium phosphate (PZr) was performed in Example 4 as the coating base, and the base treatment using titanium phosphate (PTi) was used in Example 5. In Comparative Examples 3 and 4, the base treatment using phosphoric acid chromate (PCr) was performed, but for Examples 1 to 3 and 6 to 23 and Comparative Examples 1, 2 and 5 to 14, normally, No pretreatment such as phosphoric acid chromate used as a precoating aluminum plate was applied. In addition, the comparative example 4 is an Example equivalent product of patent document 4 (patent 4237975 gazette).

  Next, on the surfaces of these aluminum base plates, the resin components shown in Table 1 and Table 2, the content of silica components (% by mass), the content of lubricating components (% by mass), the particle size (μm) of the lubricating components, A film-forming agent having the kind of optical property adjusting fine particles, the particle size (μm) of the optical property adjusting fine particles, and the amount (% by mass) of the optical property adjusting fine particles is applied by a roll coat method and baked at a heating temperature of 230 ° C. for 30 seconds. Thus, a resin film having an average film thickness (μm) shown in Table 1 and Table 2 was formed and used as precoated aluminum plates for electronic devices of Examples 1 to 23 and Comparative Examples 1 to 14 (hereinafter simply referred to as “Examples”). 1 ”,“ Comparative Example 1 ”, etc.).

Polyethylene wax was used as a lubricating component in Examples 1 to 23 and Comparative Examples 1 to 14.
Moreover, in the resin component of Table 1 and Table 2, A represents an acrylic resin, U represents a urethane resin, P represents a polyester resin, E represents an epoxy resin, and numerical values shown in parentheses represent a composition ratio.
In the types of optical property adjusting particles in Table 1, A represents acrylic resin fine particles, P represents polyethylene resin fine particles (polyolefin type), and G represents glass fine particles.

In addition, the surface roughness (arithmetic average roughness Ra) of the aluminum base plate is in a direction perpendicular to the rolling direction of the aluminum base plate using a surface roughness measuring machine (Surfcoder SE-30D, manufactured by Kosaka Laboratory Ltd.). The measurement was performed by scanning and calculating the arithmetic average roughness Ra (JIS B0601).
Moreover, about the manufactured Examples 1-23 and Comparative Examples 1-14, electroconductivity (resistance value (ohm)), lubricity (friction coefficient), fingerprint resistance (color difference ((DELTA) E)), wrinkle resistance, corrosion resistance (Rating number (RT No.)) was evaluated. These were measured and evaluated as follows.

<Conductivity>
As for conductivity, an LCR meter (4263B manufactured by HEWLETT PACKARD) is used as the tester 20, and as shown in FIG. 2, one terminal 21 of the tester 20 is sanded with a part of the resin film of the pre-coated aluminum plate for electronic equipment. The aluminum base plate exposed by polishing with paper is brought into direct conductive contact, and the other terminal 22 of the tester 20 is formed into a spherical terminal 23 (this spherical terminal 23 is formed in a substantially spherical shape with a tip portion having a radius of 10 mm. The measurement point was measured by applying a current of 0.4 N (≈40 gf) from the top of the resin film of the precoated aluminum plate for electronic equipment to the measurement location via a measuring rod made of brass. In the measurement, the surfaces of the terminal 21 and the spherical terminal 23 were previously polished with sandpaper, and zero point correction was performed in a state where the tip portion of the terminal 21 and the tip portion of the spherical terminal 23 were in contact with each other. This measurement was performed while randomly changing the position of the spherical terminal 23 to calculate an average value. When the average resistance value passed 10Ω or less, it exceeded 10Ω.

<Lubricity>
The lubricity was randomly selected on the surface of each pre-coated aluminum plate for electronic equipment by the Bowden-Leben method (steel ball φ3 / 16 inch (4.7625 mm), load 2N (200 gf), sliding speed 200 mm / min). The friction coefficient at three locations was measured and the average value was calculated.
If the average value of the friction coefficient is 0.2 or less, there is no particular problem in the molding usually performed in various electronic devices, and if it is 0.1 or less, it can be evaluated that it is particularly good. And the case of exceeding 0.2 was regarded as rejected.

<Fingerprint resistance>
For fingerprint resistance, the color difference (ΔE) before and after the fingerprint adheres by touching the surfaces of Examples 1 to 23 and Comparative Examples 1 to 14 with a spectrocolorimeter (CM-600d) manufactured by Konica Minolta. Measured using.
If the color difference ΔE value is 0.5 or less, the fingerprint attached to the surface could hardly be confirmed with the naked eye, so it was accepted, and if it exceeded 0.5, the fingerprint attached to the surface was confirmed with the naked eye. Was rejected.

<Wear resistance>
The scratch resistance was evaluated by a shear bending test method. That is, as shown in FIG. 4, the test piece of Examples 1-23 and Comparative Examples 1-14 is pinched | interposed with the upper metal mold | die 31 and the lower metal mold | die 32, and the punch 33 has the surface which formed the resin film of the test piece. We tried to reproduce the wrinkles that occur during the molding process by pressing by bending so as to slide. The interval (die interval) generated between the lower die 32 and the punch 33 was an interval obtained by adding 10% clearance to the plate thickness of the test piece used.
The sliding surface of the bent test piece is visually observed, and it is digitized by assigning a score of 0 (inferior) to 5 (excellent) depending on the degree of bending flaw on each test piece. Evaluation was performed. The same experiment was performed 5 times, and those having an average value of 2 or more points were accepted, and those having an average value less than 2 were rejected.

<Corrosion resistance>
Corrosion resistance was evaluated by conducting a test according to the neutral salt spray test defined in JISZ2271. That is, a 5 mass% sodium chloride aqueous solution was used as a spray liquid sprayed on the stretch test sample, the spray environment temperature was 35 ° C., the spray amount was 80 cm ² , and the amount was 1.5 ml per hour. The maximum test time was 100 hours.
Corresponding to the rating number method that quantifies the degree of corrosion based on the corrosion area ratio, the corrosion that occurred in the stretched test sample was quantified, and the rating number (RT No.) is 9.0 or more And those with a rating number below 9.0 were rejected.

  These evaluation results are shown in Tables 3 and 4.

(result)
From the contents shown in Tables 1 to 4, the following became clear.
(Influence of surface roughness of aluminum base plate (arithmetic mean roughness Ra))
In Comparative Example 1, the arithmetic average roughness Ra was less than the lower limit value of the range defined in the present invention, so that the fingerprint resistance and wrinkle resistance did not satisfy the acceptance criteria. In Comparative Example 2, the arithmetic average roughness Ra exceeded the upper limit value regulated by the present invention, so that the lubricity, scratch resistance and corrosion resistance did not satisfy the acceptance criteria.

(Influence of average film thickness of resin film)
In Comparative Example 5, since the average film thickness of the resin film was less than the lower limit of the range defined in the present invention, the fingerprint resistance, wrinkle resistance and corrosion resistance did not satisfy the acceptance criteria. Moreover, since the average film thickness of the resin film exceeded the upper limit of the range prescribed | regulated by this invention, the comparative example 6 resulted in a resistance value not satisfy | filling an acceptance | permission standard.

(Influence of resin component of resin film)
Since Comparative Example 7 uses only acrylic resin, Comparative Example 8 uses only urethane resin, Comparative Example 9 uses only polyester resin, and Comparative Example 10 Since only the epoxy resin was used, the corrosion resistance did not satisfy the acceptance criteria. Moreover, about the comparative example 8, since only the urethane resin was used, the result which does not satisfy an acceptance standard also with respect to a rust resistance.

  In addition, about the Example 1 which used the acrylic resin component and the urethane resin component together as a resin component, and the Examples 18-23, the ratio of an acrylic resin component and a urethane resin component, and the corrosion resistance result were compared. As a result, in Example 23 where the acrylic resin component: urethane resin component was 5:95 and the acrylic resin component: urethane resin component was 95: 5 in Example 1, the rating number was 9, Resin component: Example 22 with 10:90 urethane resin component, Example 21 with acrylic resin component: 15:85 urethane resin component, and Example 18 with acrylic resin component: 90:10 urethane resin component are rated numbers In Example 20 in which the acrylic resin component: urethane resin component was 50:50 and in Example 19 in which the acrylic resin component: urethane resin component = 85: 15, the rating number was 9 More desirable result with .5.

(Influence of silica content of resin film)
In Comparative Examples 11 and 12, since the content of the silica component was less than the lower limit value of the range defined in the present invention, the corrosion resistance did not satisfy the acceptance criteria.

(Influence of the content of the lubricating component of the resin film)
In Comparative Example 13, since the content of the lubricating component was less than the lower limit value of the range defined in the present invention, the lubricity did not satisfy the acceptance criteria.

  On the other hand, the surface roughness (arithmetic average roughness Ra), the average film thickness, the resin component in the resin film, the content of the silica component, and the content of the lubricating component all satisfy the range defined in the present invention. In Examples 1 to 17, there were no problems in all of the conductivity, lubricity, fingerprint resistance, scratch resistance and corrosion resistance.

  For Comparative Example 14, the surface roughness (arithmetic average roughness Ra), average film thickness, resin component in the resin film, content of the silica component, and content of the lubricating component are all included in the present invention. However, only the electrical conductivity did not satisfy the acceptance criteria of the present invention. This is probably because the arithmetic average roughness Ra is near the lower limit and the average film thickness is near the upper limit. Therefore, although the various parameters defined in the present invention are necessary conditions to ensure conductivity, it can be said that they are not sufficient conditions. Therefore, the desired effects of the present invention, that is, conductivity, lubricity, resistance to resistance. In order to surely exhibit the effect of excellent fingerprint property, scratch resistance and corrosion resistance, it is necessary to specify that the resistance value measured by a specific method is 10Ω or less.

  Comparative Examples 3 and 4 satisfy all of the acceptance criteria of the present invention in terms of the effect to be obtained, but since the ground treatment film contains chromium, the comparative examples that do not satisfy the criteria of the present invention are included in the meaning of the present invention. Positioned.

  As described above, the pre-coated aluminum plate for electronic equipment according to the present invention has been described by the detailed description of the invention. However, the gist of the present invention is not limited to the above-described contents, and is appropriately within the scope based on the technical idea of the present invention. It should be understood that such a range is included in the technical idea of the present invention.

10, 10 'Pre-coated aluminum plate for electronic equipment 11 Aluminum base plate 12 Resin coating 13 Base treatment coating containing no chromium

Claims (5)

A pre-coated aluminum plate for electronic equipment in which a resin film is formed on at least one surface of an aluminum base plate having an arithmetic average roughness Ra of 0.3 μm or more and 0.5 μm or less without providing a base treatment film containing chromium. ,
The resin film does not include a metal element, and includes an acrylic resin component, a urethane resin component, a silica component, and a particulate lubricating component,
The content of the silica component in the resin film exceeds 12% by mass,
The content of the lubricating component contained in the resin film exceeds 8% by mass,
The average film thickness of the resin film is 0.15 μm or more and 1.0 μm or less,
The resistance value between the spherical terminal and the aluminum base plate when a spherical terminal having a radius of 10 mm is pressed with a load of 0.4 N against the aluminum base plate on which the resin film is formed is 10Ω or less. A precoated aluminum plate for electronic equipment, which is characterized in that   2. The precoated aluminum plate for electronic equipment according to claim 1, wherein no base treatment film is provided between the aluminum base plate and the resin film.   3. The precoated aluminum plate for electronic equipment according to claim 1, wherein a particle diameter of the lubricating component contained in the resin film is 2.5 μm or less.   4. The resin film according to claim 1, further comprising 1% by mass or more and 30% by mass or less of optical property adjusting fine particles having an average particle size of 0.3 μm or more and 15 μm or less. Pre-coated aluminum plate for electronic equipment.   5. The precoated aluminum for an electronic device according to claim 1, wherein a chromium content as an additive element for the alloy contained in the aluminum base plate is less than 0.1% by mass. Board.

Images