JP2013056441A - Conductive precoated aluminum alloy plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive precoated aluminum alloy plate which is excellent in ablation resistance, easy in mold workability, and displays excellent conductivity.SOLUTION: The conductive precoated aluminum alloy plate 1 consists of a substrate 2 consisting of aluminum or an aluminum alloy, a formed film 3 formed on one side or both sides thereof, and a conductive coat 4 formed thereon. The conductive coat 4 consists of a silicate, urethane resin, colloidal silica, surfactant and wax, and also the thickness T of the coat is ≥0.05 μm and ≤1.0 μm. The silicate is at least one selected from lithium silicate, sodium silicate, potassium silicate and ammonium silicate. The urethane resin is an aliphatic ester type or an aliphatic ester-ether type, and the glass transition point is ≥90°C and ≤150°C.

Description

  The present invention relates to a precoated aluminum alloy plate used for an electrical equipment casing or the like.

  A pre-coated aluminum alloy plate obtained by coating the surface of an aluminum alloy plate with a synthetic resin paint has excellent characteristics that it is excellent in corrosion resistance, is lightweight, and does not need to be coated after forming. For this reason, pre-coated aluminum alloy sheets are widely used as materials for housings of electronic devices such as home appliances and OA devices.

  Since electronic devices often generate electromagnetic waves, members used for a housing or the like are required to be conductive in order to suppress adverse effects due to the electromagnetic waves. When a general resin is coated on the surface of an aluminum alloy plate, it is charged and causes various electronic problems. For this reason, the synthetic resin paint (organic resin paint) has conductivity.

In recent years, with the globalization of parts manufacturing sites and the orientation of original combinations by end users, the number of cases transported in the state of parts has increased. These products may be rubbed or rubbed with the packaging material due to vibration during transportation or the like, and the surface may be abraded (ablated). Such scratches significantly deteriorate the commercial value.
Furthermore, higher performance, smaller and lighter devices, and safety for human bodies are becoming more important, and there is an increasing demand for suppressing electromagnetic waves from electronic devices. For this reason, the request | requirement of electroconductivity is stronger than before.

As a precoat aluminum alloy plate, for example, an aluminum plate having a resin film containing Zr has been proposed (see Patent Document 1).
Moreover, an aluminum plate having a coating film using a combination of colloidal silica and water glass or polyvinyl alcohol has been proposed (see Patent Document 2).
In addition, a metal plate having a glassy film made of a dry gel of silica particles containing wax on the surface has been proposed (see Patent Documents 3 and 4).

JP 2001-205730 A JP 2009-28991 A JP-A-8-196989 Japanese Patent Laid-Open No. 9-057188

  However, although a resin film containing Zr can exhibit high conductivity, it is difficult to meet the demand for higher conductivity in recent years. Moreover, in the coating film which employ | adopted the combination of colloidal silica, water glass, or polyvinyl alcohol, ablation resistance is inferior. In addition, a vitreous film composed of a dry gel of silica particles containing wax can exhibit good ablation resistance, but the metal plate surface is covered with vitreous, so that cracks occur in the processed part such as bending. May occur. And it becomes easy to generate | occur | produce corrosion in the cracked part. Further, there is a problem that when the film thickness is reduced, it becomes difficult to form a film.

  The present invention has been made in view of such a background, and provides a conductive pre-coated aluminum alloy plate that has excellent ablation resistance, can be easily formed, and can exhibit excellent conductivity. It is.

One aspect of the present invention comprises a substrate made of aluminum or an aluminum alloy, a chemical conversion film formed on one or both surfaces of the substrate, and a conductive coating film formed on the chemical conversion film.
The conductive coating film is composed of silicate, urethane resin, colloidal silica, surfactant, and wax, and has a film thickness T of 0.05 μm or more and 1.0 μm or less,
The silicate is at least one selected from lithium silicate, sodium silicate, potassium silicate, and ammonium silicate,
The urethane resin is an aliphatic ester type or an aliphatic ester-ether type, and has a glass transition point of 90 ° C. or more and 150 ° C. or less,
The colloidal silica has a primary particle size of 5 nm or more and 100 nm or less,
The surfactant has a dynamic surface tension of 43.8 mN / m or less at a temperature of 25 ° C. measured by the Wilfermy method,
The wax has a primary particle size of 0.05 μm or more and 6 μm or less, a softening point by a ring and ball method of 113 ° C. or more and 135 ° C. or less, and a penetration at a temperature of 25 ° C. of 3 mm or less by a hardness method. A conductive pre-coated aluminum alloy plate characterized in that (1).

  The conductive pre-coated aluminum alloy plate has the conductive coating film formed on the chemical conversion film. Therefore, the conductive pre-coated aluminum alloy plate has excellent ablation resistance, can be easily formed, and can exhibit excellent conductivity.

Explanatory drawing which shows the cross-section of the electroconductive precoat aluminum alloy plate in an Example. Explanatory drawing which shows the evaluation method of ablation resistance in an Example. Explanatory drawing which shows the state which pinched | interposed the electroconductive precoat aluminum alloy plate between the dice | dies and wrinkle holding | suppressing of a press work machine, and made the punch contact | abut the electroconductive precoat aluminum alloy plate in an Example. Explanatory drawing which shows a mode that a conductive precoat aluminum alloy plate is bent in a U-shape with the press processing machine in an Example. Explanatory drawing which shows the electroconductive precoat aluminum alloy plate by which the convex part was processed in the reverse U shape in the Example, and the convex part was partially formed. In the Example, it is a photograph of the sliding part of the aluminum alloy plate showing the evaluation result of the ablation resistance, and is an explanatory view (a) showing a photograph when no flaw is seen at all, when the sliding part is lightly discolored Explanatory drawing (b) showing a photograph of the above, explanatory drawing (c) showing a photograph when peeling of the coating film is seen in less than 50% of the sliding portion, coating film in the sliding portion of 50% or more and less than 75% Explanatory drawing (d) which shows the photograph when peeling of a film is seen, and explanatory drawing (e) which shows the photograph when peeling of a coating film is seen in 75% or more of sliding parts.

Next, a preferred embodiment of the present invention will be described.
The conductive precoated aluminum alloy plate includes a substrate made of aluminum or an aluminum alloy, a chemical conversion film formed on one or both surfaces of the substrate, and a conductive coating film formed on the chemical conversion film.
As the substrate, for example, a metal plate made of various aluminum alloys such as pure aluminum or 5000 series aluminum can be used.

  The chemical conversion film is a film that improves the adhesion between the substrate and the conductive coating film. For example, a chemical conversion film made of phosphate chromate, zirconium phosphate, zirconium oxide, chromate chromate, or the like can be formed.

The conductive coating film contains a silicate, a urethane resin, colloidal silica, a surfactant, and a wax.
Hereinafter, each component which comprises a conductive coating film is demonstrated.

(Silicate)
The silicate is at least one or more selected from lithium salts, sodium salts, potassium salts, and ammonium salts. From the viewpoint of film forming property, a lithium salt is preferable, and from the viewpoint of corrosion resistance, an ammonium salt is preferable.

When the silicate is lithium silicate, the SiO ₂ / Li ₂ O molar ratio in the silicate is preferably 3.5 to 7.5 (Claim 7).
When the SiO ₂ / Li ₂ O molar ratio is less than 3.5, silicic acid is likely to precipitate and film formation may be difficult. On the other hand, if the molar ratio of SiO ₂ / Li ₂ O exceeds 7.5, the drying property may be increased and it may be difficult to obtain a smooth coating film. The molar ratio of SiO ₂ / Li ₂ O in the silicate is more preferably 3.5 to 4.5.

When the silicate is sodium silicate, the SiO ₂ / Na ₂ O molar ratio in the silicate is preferably 0.5 to 4.0 (claim 8).
When the SiO ₂ / Na ₂ O molar ratio is less than 0.5, silicic acid is likely to precipitate and film formation may be difficult.
On the other hand, if the molar ratio of SiO ₂ / Na ₂ O exceeds 4.0, the drying property becomes high and it may be difficult to obtain a smooth coating film. The molar ratio of SiO ₂ / Na ₂ O in the silicate is more preferably 2.4 to 3.9.

When the silicate is potassium silicate, the molar ratio of SiO ₂ / K ₂ O in the silicate is preferably 1.8 to 3.7 (Claim 9).
When the molar ratio of SiO ₂ / K ₂ O is less than 1.8, silicic acid is likely to precipitate, and film formation may be difficult. On the other hand, when the molar ratio of SiO ₂ / K ₂ O exceeds 4.0, there is a possibility that the drying property becomes high and it becomes difficult to obtain a smooth coating film. The SiO ₂ / K ₂ O molar ratio in the silicate is more preferably 2.7 to 3.7.

When the silicate is ammonium silicate, the SiO ₂ / NH ₃ molar ratio in the silicate is preferably 24 to 57 (claim 10).
When the SiO ₂ / NH ₃ molar ratio is less than 24, silicic acid is likely to precipitate and film formation may be difficult. On the other hand, when the molar ratio of SiO ₂ / NH ₃ exceeds 57, there is a possibility that the drying property becomes high and it becomes difficult to obtain a smooth coating film. The SiO ₂ / NH ₃ molar ratio in the silicate is more preferably 28-42.

(Urethane resin)
The urethane resin preferably has a glass transition point of 90 ° C. or higher and 150 ° C. or lower.
When the glass transition point is less than 90 ° C., the hardness of the conductive coating film is lowered, and the press workability may be lowered. on the other hand,
When the glass transition point exceeds 150 ° C., the flexibility of the conductive coating film is lost and the workability may be lowered.
The glass transition point of the urethane resin can be adjusted to a desired value by selecting the molecular weight and the main skeleton used for the urethane resin.

Moreover, as a kind of urethane resin, an aliphatic ester type or ether-ester type urethane resin is preferable from a viewpoint of film forming property. A urethane resin having an aromatic ester skeleton is not preferable because it has low affinity with silicate and film formation becomes difficult.
The urethane resin is obtained by polymerizing a polyfunctional isocyanate, a polyhydric alcohol, and a bifunctional active hydrogen-containing compound having an acidic group or the like by a known method.

  Examples of the polyvalent isocyanate include ethylene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane-1,4-diisocyanate, and 4,4′-dicyclohexylmethane diisocyanate. Furthermore, mixtures of these can be used.

  Moreover, as a polyhydric alcohol, what is known as a well-known raw material for polyurethane emulsion synthesis can be used. For example, ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, neopentyl glycol, cyclohexanedimethanol, glycerol, trimethylolpropane, pentaerythritol, polyester polyol, polyester polyamide polyol, polyether polyol, polythioethylene Examples include terpolyol, polycarbonate polyol, polyacetal polyol, polyolefin polyol, and polysiloxane polyol.

  Moreover, what is conventionally known as a synthetic raw material of an anionic polyurethane emulsion can be used as a bifunctional active hydrogen containing compound which has an acidic group. Examples thereof include 2,2-dimethylolpropanoic acid, 2,2-dimethylolbutanoic acid, lysine, cystine, 3,5-diaminobenzoic acid and the like.

  The method for synthesizing the urethane resin is not particularly limited, and those synthesized by an industrially used method can be used. Further, the urethane resin can be used after neutralizing with sodium hydroxide or potassium hydroxide.

Examples of commercially available aliphatic ester urethane resins include Adekabon titer HUX-232 and HUX-350 manufactured by ADEKA.
Examples of commercially available aliphatic ester-ether urethane resins include Adekabon titer HUX-350 and HUX-522 manufactured by ADEKA.

It is preferable that the said conductive coating film contains 5 mass parts or more and 100 mass parts or less of urethane resin with respect to 100 mass parts of solid content of a silicate (Claim 2).
In this case, coating film peeling at the time of shaping | molding can be prevented further, and workability can be improved more. In this case, the ablation resistance can be further improved.

(Colloidal silica)
Colloidal silica has a primary particle diameter of 5 nm or more and 100 nm or less.
When the primary particle size is less than 5 nm, the electrical resistance increases, and the effect of improving the conductivity due to the addition of colloidal silica may be reduced. On the other hand, when the thickness exceeds 100 nm, it becomes difficult to form a conductive coating film with a uniform thickness when forming the conductive coating film, and a part where the conductive coating film is not partially formed is generated. There is a possibility that the coating film is easily peeled off. Moreover, there exists a possibility that the electrical resistance of an electroconductive coating film may become large and electroconductivity may fall.

Each particle in a dispersed state before aggregation is referred to as a primary particle, and the primary particle diameter is the diameter of the primary particle. The particles after aggregation are called secondary particles, and the diameter of the secondary particles is called secondary particle diameter.
The primary particle size of the colloidal silica can be obtained by drying the colloidal silica, obtaining the specific surface area using the BET method (specific surface area measurement method), and calculating backward from the weight and density. Specifically, the total specific surface area of the total amount of colloidal silica to be used can be determined by the BET method, and the primary particle diameter (average value) can be calculated from the total weight and density.

Colloidal silica in the conductive coating when the total amount of the silicate, the urethane resin and the thickener as a selective component described later is 100 parts by mass (dry weight) in the conductive coating. The content of is preferably 1 part by mass or more and 60 parts by mass or less.
In this case, the conductivity can be further improved. Moreover, even if it adds colloidal silica exceeding 60 mass parts, the addition effect will be saturated. As for content of colloidal silica, it is more preferable that the dry weight of a conductive coating film is 5 to 40 mass parts with respect to 100 mass parts. The colloidal silica content is the content when the total amount of silicate, urethane resin and thickener in the conductive coating film is 100 parts by mass (dry weight). When the conductive coating does not contain a thickener as a selective component, it is the content when the total amount of silicate and urethane resin in the conductive coating is 100 parts by mass (dry weight). .

  A commercially available product can be used as the colloidal silica. Specific examples include Snowtex N, Snowtex CM, Snowtex 20L, Snowtex YL, Snowtex ZL, etc., manufactured by Nissan Chemical Co., Ltd.

(wax)
The wax preferably has a primary particle size of 0.05 μm or more and 6 μm or less.
If the primary particle system of the wax is less than 0.05 μm, the effect of adding the wax may be difficult to obtain. On the other hand, when the thickness exceeds 6 μm, the wax may drop off during press forming of the conductive precoated aluminum alloy plate. More preferably, the primary particle diameter of the wax is 0.5 to 3 μm.

  The primary particle diameter of the wax can be measured by a Coulter counter method. The primary particle size of the wax means the particle size at an integrated value of 50% in the particle size distribution obtained by the Coulter counter method.

The wax preferably has a softening point of 113 ° C. or more and 135 ° C. or less by the ring and ball method.
The wax having a softening point of less than 113 ° C may be melted when the conductive coating is baked. As a result, the lubricity of the conductive coating film may be insufficient. In addition, the wax having a softening point exceeding 135 ° C. may cause insufficient fusion with the conductive coating film, causing the inner wax to fall off, resulting in insufficient lubrication.
The softening point of the wax can be defined according to a method (ring ball method) defined in JIS K 2207 (1980).

The wax preferably has a penetration of 3 mm or less by a hardness method at a temperature of 25 ° C. The wax having a penetration of more than 3 mm is easily deformed and may be deformed when the coil is wound after coating and baking, and sufficient lubricity may not be obtained. The penetration of the wax by a hardness method at a temperature of 25 ° C. is more preferably 1 mm or less.
The penetration of wax can be measured by the method defined in JIS K 2207 (1980).

When the total amount of the silicate, the urethane resin, and the thickener, which is a selective component described later, is 100 parts by mass (dry weight) in the conductive coating film, the wax in the conductive coating film The content is preferably 0.05 parts by mass or more and 25 parts by mass or less (Claim 6).
In this case, ablation property and moldability can be further improved. In addition, the contact angle of oil and moisture can be reduced, and fingerprint resistance can be further improved. The content of the wax is a content when the total amount of the silicate, the urethane resin, and the thickener in the conductive coating film is 100 parts by mass (dry weight). When the coating film does not contain a thickener as a selective component, the content is the total amount of the silicate and the urethane resin in the conductive coating film being 100 parts by mass (dry weight).

  Examples of the wax that can be used include polyethylene and microclostaline. Among these, it is preferable to use polyethylene wax.

(Surfactant)
The surfactant preferably has a dynamic surface tension of 43.8 mN / m or less at a temperature of 25 ° C. measured by the Wilfermy method.
When the dynamic surface tension of the surfactant exceeds 43.8 mN / m, the foaming force increases and there is a possibility that a coating film defect is generated.

  Surfactants include, for example, higher alcohols that have little effect on the emulsion structure in paints, nonionic surfactants in which ethylene oxide is added to polyhydric alcohols, or a portion of ethylene oxide in the polyhydric alcohol ethylene oxide adducts. A nonionic surfactant substituted with can be used.

Examples of commercially available polyoxyethylene type nonionic surfactants include New Coal NT-7, New Coal NT-9, New Coal 1006, New Coal 1008, and New Coal 1525 manufactured by Nippon Emulsifier Co., Ltd. .
Examples of commercially available polyoxyethylene polyoxypropylene type nonionic surfactants include, for example, Neugen SDX-60, Neugen SDX-70 manufactured by Daiichi Kogyo Seiyaku, Neoscore AS-0349 manufactured by Toho Chemical Co., Ltd., Pepol AS -053X, Pepol AS-054C, Toho Polyol MEB-142, Toho Polyol MEB-145, Toho Polyol MEB-147, Neo Solvent NSG-E, New Call 2303-Y, New Call 2303-YM manufactured by Nippon Emulsifier Co., Ltd. New call 2304-Y, New call 2306-Y, New call 2308-Y, New call 2314-Y, New call 2306-HY, New call 2308-HY, New call 1008-F1, New call 1902-Y, New Le 1308FA (90), and the like DMH-40.

The conductive coating is formed by applying and curing a conductive paint, and the conductive paint contains 0.05 to 5 parts by mass of the surfactant with respect to 100 parts by mass of the conductive paint. (Claim 3).
When the content is less than 0.05 parts by mass, it may be difficult to form a coating film with a uniform thickness. On the other hand, even if added over 5 parts by mass, the effect of addition is saturated.

(Other)
Moreover, it is preferable that the said electrically conductive coating material contains a thickener. In this case, paintability can be improved.
As the thickener, for example, a thixotropic thickener can be used.
Examples of commercially available thixotropic thickeners include, for example, Rheojic 250H, Rheojic 252L, Rheodig 835L, Rheogic 830L, Rheogic 305H, and Rheogic 306L manufactured by Nippon Pure Chemical Industries.

Moreover, as said thickener, water-soluble acrylic can be used, for example.
Examples of commercially available water-soluble acrylics include Jurimer AT-210, AT-510, AT-613, AC-10L, and AC-20L manufactured by Nippon Pure Chemical Industries.

The content of the thickener in the conductive paint is preferably 100 parts by mass or less with respect to 100 parts by mass of the solid content of silicate.
When a thickener exceeds 100 mass parts, the softness | flexibility of the said conductive coating film is lost and there exists a possibility that workability may fall. The content of the thickener is more preferably 50 parts by mass or less. The content of the thickener can be 0 parts by mass.

The conductive coating film preferably has a film thickness T of 0.05 μm or more and 1.0 μm or less.
When the film thickness T is less than 0.05 μm, fingerprint resistance may be reduced. On the other hand, if the thickness exceeds 1.0 μm, the electrical resistance may increase and the conductivity may decrease. The film thickness T of the conductive coating film is more preferably 0.05 μm or more and 0.5 μm or less.

Moreover, in the said conductive precoat aluminum alloy plate, when the electrical resistance of the 20 surface parts from which the said conductive coating film differs is measured by the acicular electrode method, there exists electrical conduction in 10 or more surface parts. And it is preferable that the average value of the electrical resistance of the 20 surface parts is 10Ω or less (claim 11).
In this case, the said electroconductive precoat aluminum alloy plate can be utilized suitably for various uses which require electroconductivity.

The needle electrode method is a load in which a pure copper needle having a spherical needle tip of φ0.2 mm is placed on the surface of the conductive coating film, and the needle tip does not penetrate the conductive coating film. Is applied to the needle, and in this state, the electrical resistance value of the conductive coating film at the portion where the needle tip is in contact is established by conducting between the substrate exposed by removing the film and the needle. It is.
Further, the 20 different locations are 20 locations that are evenly distributed 30 mm inside from the end of the A4 plate sample.

When there are less than 10 sites with electrical continuity in the 20 different surface sites, there may be a portion with poor electromagnetic shielding properties.
Moreover, when the average value of the electrical resistance of the 20 different surface portions exceeds 10Ω, there is a possibility that a portion with poor electromagnetic shielding properties may occur.

The conductive pre-coated aluminum alloy plate can be suitably used for, for example, an electric equipment casing or an electronic equipment casing by press-forming the conductive pre-coated aluminum alloy sheet.
Examples of the electrical device casing or the electronic device casing include, for example, a personal computer body, a casing of an electronic device such as a CD-ROM, a DVD, and a PDA, a casing of an electric device such as a television, FDD, MD, There are various other things such as the shutter part of a storage medium case such as MO.

Example 1
Next, the electroconductive precoat aluminum alloy plate of an Example and a comparative example is demonstrated.
In this example, as shown in Tables 2 to 9 described later, 38 types of precoated aluminum alloy plates (Sample 1 to Sample 38) were produced, and various performance evaluation tests were performed.

The structure of the conductive precoated aluminum alloy plate according to the example is shown in FIG.
The precoated aluminum alloy plate 1 includes a substrate 2 made of an aluminum alloy, a chemical conversion film 3 formed on one surface thereof, and a conductive coating film 4 formed on the chemical conversion film 3.
The conductive coating film 4 is made of silicate, urethane resin, colloidal silica, surfactant, and wax, and has a film thickness T of 0.05 μm or more and 1.0 μm or less.

  In the conductive coating film 4, the silicate is at least one selected from lithium silicate, sodium silicate, potassium silicate, and ammonium silicate. The urethane resin is an aliphatic ester type or an aliphatic ester-ether type, and has a glass transition point of 90 ° C. or higher and 150 ° C. or lower. Colloidal silica has a primary particle diameter of 5 nm or more and 100 nm or less. The surfactant has a dynamic surface tension of 43.8 mN / m or less at a temperature of 25 ° C. measured by the Wilfermy method. The wax has a primary particle size of 0.05 μm or more and 6 μm or less, a softening point by the ring and ball method of 113 ° C. or more and 135 ° C. or less, and a penetration at a temperature of 25 ° C. of 3 mm or less by the hardness method.

  In the conductive pre-coated aluminum alloy plate of each sample (sample 1 to sample 38) produced in this example, the type of chemical conversion film, silicate constituting the conductive film, urethane resin, colloidal silica, wax, surface activity The type and blending ratio of the agent and other configurations were changed for each sample as shown in Tables 2 to 7 described later.

In producing each sample, first, a 5052-H34 material having a plate thickness of 1.0 mm was prepared as the substrate 2 made of an aluminum alloy plate. The surface roughness Ra of the substrate 2 is Ra = 0.3 μm.
Next, a chemical conversion treatment for forming a chemical conversion film 3 was performed on the substrate 2. Table 1 shows the four types of chemical conversion treatments (ad) adopted in this example.
In the chemical conversion treatment a, a reactive chromate film is formed by phosphoric acid chromate treatment so that the chromium amount becomes 20 mg / m ² . Specifically, the chemical conversion treatment was performed by immersing the sample in the chemical conversion treatment solution, and then dried in an atmosphere of about 100 ° C.

In the chemical conversion treatment b, a reactive non-chromate film is formed by zirconium treatment so that the amount of zirconium becomes 20 mg / m ² . The treatment method is the same as the chemical conversion treatment a.
The chemical conversion treatment c is a product in which a coating type chromate film is formed by a coating type chromate treatment so that the chromium amount becomes 20 mg / m ² . Specifically, after the substrate was degreased, a treating agent was applied by a bar coating method and then dried in an atmosphere at about 100 ° C.
In the chemical conversion treatment d, a coating-type non-chromate film is formed by coating-type zirconium treatment so that the amount of zirconium is 20 mg / m ² . The treatment method is the same as the chemical conversion treatment c.

Next, the conductive coating film 4 was formed on the chemical conversion film 3 by baking a conductive paint.
The conductive paint is made by mixing various components such as silicate, urethane resin, colloidal silica, inner wax, surfactant, and thickener so as to have a blending ratio shown in Tables 2 to 7 in solid content. The adjusted conductive paint was prepared using butyl cellosolve and deionized water as solvents. At this time, it adjusted with deionized water so that solid content might be 5 mass%.

As the silicate, lithium silicate, sodium silicate, potassium silicate, or ammonium silicate was used.
Specifically, “lithium silicate 35” manufactured by Nippon Chemical Industry Co., Ltd. was used as the lithium silicate having a SiO ₂ / Li ₂ O molar ratio of 3.6. As the lithium silicate having a SiO ₂ / Li ₂ O molar ratio of 7.5, “lithium silicate 75” manufactured by Nippon Chemical Industry Co., Ltd. was used. In addition, as lithium silicate having a SiO ₂ / Li ₂ O molar ratio of 8.5, “Lithium silicate 75” manufactured by Nippon Chemical Industry Co., Ltd. is used so that the molar ratio is 8.5. What added the acid was used.

Moreover, as sodium silicate, the molar ratio of SiO ₂ / Na ₂ O is “J sodium silicate 3” manufactured by Nippon Chemical Industry Co., Ltd. with a molar ratio of 3.2, and the molar ratio of SiO ₂ / Na ₂ O is 0. .9 “Non-metasilicate sodium hydrate” manufactured by Nippon Chemical Industry Co., Ltd. or “30% liquid manufactured by Nippon Chemical Industry Co., Ltd.” having a SiO ₂ / Na ₂ O molar ratio of 0.5. "Ortho" was used.
As potassium silicate, “A potassium silicate” manufactured by Nippon Chemical Industry Co., Ltd. having a SiO ₂ / K ₂ O molar ratio of 3.0 was used.
As the ammonium silicate, “Silica Doll 30B” manufactured by Nippon Chemical Industry Co., Ltd. having a SiO ₂ / NH ₃ molar ratio of 34 was used.

  Also, as the urethane resin, ADEKA Bontiter HUX-350 (ether urethane resin, glass transition point 140 ° C.) manufactured by ADEKA, Adekabon Titer HUX-232 (aliphatic ester urethane resin, glass transition manufactured by ADEKA) Adekabon titer HUX-522 (aliphatic ester-based urethane resin, glass transition point 150 ° C) manufactured by ADEKA, or Adekabon titer HUX-320 (aromatic ester-based urethane resin, glass manufactured by ADEKA) Transition point 120 ° C.) was used.

  Further, as colloidal silica, SNOWTEX YL (primary particle diameter 80 nm), SNOWTEX ZL (primary particle diameter 100 nm), SNOWTEX MP2040 (primary particle diameter 200 nm), SNOWTEX S (primary particle diameter) manufactured by Nissan Chemical Co., Ltd. 8 nm) or Snowtex XS (primary particle size 4 nm).

As the wax, polyethylene wax “W900”, “W500”, or “W4005” manufactured by Mitsui Chemicals, Inc. was used.
“W900” has a primary particle diameter of 0.6 μm, a softening point by the ring and ball method of 132 ° C., and a penetration by the hardness method at a temperature of 25 ° C. of less than 1 mm.
“W500” has a primary particle diameter of 0.6 μm, a softening point by the ring and ball method of 113 ° C., and a penetration by the hardness method at a temperature of 25 ° C. of 10 mm.
“W4005” has a primary particle diameter of 0.6 μm, a softening point by the ring and ball method of 110 ° C., and a penetration by the hardness method at a temperature of 25 ° C. of 3 mm.

  Further, as a surfactant, a surfactant “EOPO-” manufactured by Nippon Emulsifier Co., Ltd., which is a polyoxyethylene polypropylene type nonionic surfactant having a dynamic surface tension (Wilfermy method) of 40.3 mN / m. 1 ", surfactant" EO-1 "manufactured by Nippon Emulsifier Co., Ltd., which is a polyoxyethylene type nonionic surfactant having a dynamic surface tension (Wilfermy method) of 37.2 mN / m, or dynamic A surfactant “EO-2” manufactured by Nippon Emulsifier Co., Ltd., which is a polyoxyethylene type nonionic surfactant having a surface tension (Wilfermy method) of 46.3 mN / m, was used.

  As a thickener, Nippon Pure Chemical Industries Ltd. acrylic resin “Jurimer AT613” was used.

  As a method for applying the conductive layer coating material, there are various methods described above. In this example, the coating method was performed by a bar coating method. A conductive paint whose compounding components were adjusted so as to obtain conductive coating films having the structures shown in Tables 2 to 7 described later was applied on the chemical conversion film. Then, the baking process which hold | maintains for 40 second in the atmosphere from which the surface temperature of a board | substrate becomes about 200 degreeC was performed, and the electroconductive coating material was hardened. Thereby, the conductive coating film 4 of the structure shown in Tables 2-7 was formed on the chemical conversion film 3, and the electroconductive precoat aluminum alloy plate 1 was produced (refer FIG. 1).

  In Tables 2-7, for the conductive precoated aluminum alloy plates (Samples 1 to 38) of each sample, the type of chemical conversion film, the type of silicate, the molar ratio of silicate to salt in the silicate, silicate Addition amount (parts by mass), type of urethane resin, glass transition point of urethane resin (° C.), addition amount of urethane resin to 100 parts by mass of silicate (parts by mass), type of colloidal silica, primary particles of colloidal silica Diameter, addition amount (parts by mass) of colloidal silica to 100 parts by mass (dry weight) of the total amount of silicate, urethane resin and thickener in the conductive coating, type of wax, silicic acid in the conductive coating Addition amount (mass part) of wax with respect to 100 parts by mass (dry weight) of the total amount of salt, urethane resin and thickener, type of surfactant, inclusion of surfactant in 100 parts by mass of conductive paint The amount (parts by weight), indicating the type of thickener, the content of the thickener with respect to 100 parts by weight silicate in the conductive paint (parts by weight), and the conductive coating film having a film thickness of the ([mu] m).

  In addition, the conductive precoated aluminum alloy plate of each sample was evaluated for ablation resistance, conductivity, press workability, and fingerprint resistance.

"Ablation resistance"
Ablation resistance was determined by a reciprocating friction test shown in FIG.
Specifically, first, a wrapping film 79 was attached to the tip of the pressing jig 75 of the reciprocating friction tester 7 with a double-sided tape via a cushion material 78. As the cushion material 78, a “cotton seagull” made by Chiyoda Co., Ltd. was used, and the wrapping film 79 was a wrapping film # 4000 made by Sumitomo 3M. Next, the conductive precoated aluminum alloy plate 1 of each sample was placed on the sample stage 70 of the reciprocating friction tester 7 and fixed. Next, the wrapping film 79 attached to the pressing jig 75 was brought into contact with the surface 19 on the side where the conductive coating film was formed in the conductive precoated aluminum alloy plate 1. Then, with a load of 1 kg applied to the conductive precoated aluminum alloy plate 1 by the pressing jig 75, the sample table 70 on which the aluminum alloy plate 1 is placed is placed in the horizontal directions 71 and 72 in a 10 mm width and a speed of 20 mm / s. And slid 100 times. The sliding part in the aluminum alloy plate 1 was read with a scanner under the condition of 24 bit color and 300 dpi, and the degree of scratching of the sliding part was evaluated as follows. The results are shown in Tables 8 and 9. In addition, an example of the photograph of the sliding part of the aluminum alloy plate read with the scanner is shown to Fig.6 (a)-(e).
FIG. 6A shows an example in the case where the evaluation of the ablation resistance is the following five points, and FIG. 6B shows an example in the case where the evaluation of the ablation resistance is the following four points. ) Is an example when the ablation resistance evaluation is the following three points, FIG. 6D is an example when the ablation resistance evaluation is the following two points, and FIG. 6E is an ablation resistance evaluation. This is an example when the evaluation of the property is the following one point.

(Evaluation criteria)
5 points: when no flaws are observed at all 4 points: when the sliding portion is lightly discolored 3 points: when peeling of the coating film is observed at less than 50% of the sliding portion 2 points: 50% of the sliding portion When the peeling of the coating film is seen in less than 75% 1 point: When the peeling of the coating film is seen in 75% or more of the sliding part

"Conductivity"
The conductivity was evaluated by measuring the electrical resistance values of 20 surface portions with different conductive layers by the needle electrode method. In the needle electrode method, a pure copper needle having a spherical needle tip of φ0.2 mm is placed on the surface of the conductive coating, and a load is applied to the needle so that the needle tip does not penetrate the conductive coating. In this state, the electrical resistance value of the conductive coating film at the portion in contact with the needle tip is measured by conducting between the substrate exposed by removing the film and the needle. In this example, the load applied to the needle was uniformly set to 10 g. Of the 20 surface sites, the number of sites where the electrical resistance value could be measured and the average electrical resistance value at that time were determined. The results are shown in Tables 8 and 9.

<Press workability>
As shown in FIGS. 3 to 5, the press workability is evaluated by pressing the conductive pre-coated aluminum alloy plate 1 of each sample to form a convex portion 18 that partially protrudes toward the conductive coating film forming side. This was done by observing the occurrence of flaws on the surface of the conductive precoated aluminum alloy plate 1 after processing.
Specifically, as shown in FIG. 3, the conductive pre-coated aluminum alloy plate 1 of each sample is used as a die 101 of a press machine 100 (Ericsen test machine) and a load F ₃ (F ₃ = 3. 5kN). The die 101 is provided with a hole through which a punch 103 (40 mm square, R: 5 mm) passes. Then, as shown in FIG. 4, the punch 103 is brought into contact with the surface 16 opposite to the conductive coating forming surface 15 of the conductive precoated aluminum alloy plate 1, and the punch 103 is pushed into the hole of the die 101, The conductive precoated aluminum alloy plate 1 was projected in an inverted U shape on the side where the conductive coating film 4 was formed. The processing conditions were pressing load: 3.5 kN, processing speed: 120 mm / min, and temperature: room temperature. For processing, highly refined mineral oil was used as a lubricant.
Thus, as shown in FIG. 5, the convex part 18 which protrudes partially to the coating-film layer formation side was formed in the electroconductive precoat aluminum alloy plate 1. As shown in FIG.
And the surface of the electroconductive precoat aluminum alloy plate after press work was observed visually, the extent of a flaw was confirmed, and it evaluated based on the following evaluation criteria. The results are shown in Tables 8 and 9 below.

(Evaluation criteria)
5 points: When scratches are not seen in the coating layer of the bending portion and the sliding portion of the mold 4 points: The coating layer of the bending portion and the sliding portion of the mold has a width of less than 0.1 mm and a length of 0. Scratches of less than 5 mm are seen, but width of 0.1 mm or more and length of 0.5 mm or more are not seen 3 points: width of 0.1 mm or more on the coating layer of the bent part and the mold sliding part Scratches with a length of less than 0.2 mm and a length of 0.5 mm or more and less than 1 mm are seen, but no scratches with a width of 0.2 mm or more and a length of 1 mm or more are seen. Scratches with a width of 0.2 mm or more and less than 0.3 mm and a length of 1 mm or more and less than 2 mm can be seen in the film, but no scratches with a width of 0.3 mm or more and a length of 2 mm or more are found 1 point: bending part and mold When a scratch with a width of 0.3 mm or more and a length of 2 mm or more is seen in the coating film of the sliding part

"Fingerprint resistance"
Fingerprint resistance is obtained by cutting each sample into an area of 50 mm × 50 mm, applying 10 mg / dm ² of petrolatum to half of the area, pulling the whole up once in ethanol, and then lifting the remaining area of petrolatum. Was visually observed.
There are 5 grades, 5 points when there is no remaining, 4 points when remaining at a rate of less than 1/10, 3 points when remaining at a rate of 1/10 or more and less than 1/8, 1 / The case where it remained in the ratio of 8 or more and less than 1/4 was made 2 points, and the case where it remained ¼ or more was made 1 point. The results are shown in Tables 8 and 9 below.

  As is known from Tables 1 to 9, the conductive coating film is composed of silicate, urethane resin, colloidal silica, surfactant, and wax, and the film thickness T is 0.05 μm or more and 1. The silicate is at least one selected from lithium silicate, sodium silicate, potassium silicate, and ammonium silicate, and the urethane resin is an aliphatic ester type or an aliphatic ester-ether type. The glass transition point is 90 ° C. or higher and 150 ° C. or lower, the colloidal silica has a primary particle size of 5 nm or more and 100 nm or less, and the surfactant is a dynamic at a temperature of 25 ° C. measured by the Wilfermy method. The surface tension is 43.8 mN / m or less, the wax has a primary particle diameter of 0.05 μm or more and 6 μm or less, and a softening point by ring and ball method is 113. The conductive pre-coated aluminum alloy sheet, which is not less than 135 ° C. and has a penetration of 3 mm or less at a temperature of 25 ° C., has excellent ablation resistance, can be easily formed, and exhibits excellent conductivity. can do.

DESCRIPTION OF SYMBOLS 1 Conductive precoat aluminum alloy plate 2 Board | substrate 3 Chemical conversion film 4 Conductive coating film

Claims (11)

A substrate made of aluminum or an aluminum alloy, a chemical conversion film formed on one or both surfaces of the substrate, and a conductive coating film formed on the chemical conversion film,
The conductive coating film is composed of silicate, urethane resin, colloidal silica, surfactant, and wax, and has a film thickness T of 0.05 μm or more and 1.0 μm or less,
The silicate is at least one selected from lithium silicate, sodium silicate, potassium silicate, and ammonium silicate,
The urethane resin is an aliphatic ester type or an aliphatic ester-ether type, and has a glass transition point of 90 ° C. or more and 150 ° C. or less,
The colloidal silica has a primary particle size of 5 nm or more and 100 nm or less,
The surfactant has a dynamic surface tension of 43.8 mN / m or less at a temperature of 25 ° C. measured by the Wilfermy method,
The wax has a primary particle size of 0.05 μm or more and 6 μm or less, a softening point by a ring and ball method of 113 ° C. or more and 135 ° C. or less, and a penetration at a temperature of 25 ° C. of 3 mm or less by a hardness method. A conductive precoated aluminum alloy plate characterized by   The electroconductive precoat aluminum alloy plate of Claim 1 WHEREIN: The said electroconductive coating film contains 5 mass parts or more and 100 mass parts or less of the said urethane resin with respect to 100 mass parts of solid content of the said silicate. Conductive pre-coated aluminum alloy plate   3. The conductive precoated aluminum alloy plate according to claim 1, wherein the conductive coating film is formed by applying and curing a conductive paint, and the conductive paint is the interface with respect to 100 parts by mass of the conductive paint. An electroconductive precoated aluminum alloy plate comprising 0.05 parts by mass or more and 5 parts by mass or less of an activator.   The electroconductive precoat aluminum alloy plate of any one of Claims 1-3 WHEREIN: The said electroconductive coating film apply | coats and hardens | cures an electroconductive paint, The said electroconductive paint is solid content of silicate 100. A conductive precoated aluminum alloy plate comprising 100 parts by mass or less (including 0 parts by mass) of a thickener with respect to parts by mass.   The conductive precoated aluminum alloy plate according to claim 4, wherein the total amount of the silicate, the urethane resin, and the thickener in the conductive coating film is 100 parts by mass (dry weight). Content of the said colloidal silica in an electroconductive coating film is 1 to 60 mass parts, The electroconductive precoat aluminum alloy plate characterized by the above-mentioned.   The conductive precoated aluminum alloy plate according to claim 4 or 5, wherein the total amount of the silicate, the urethane resin, and the thickener in the conductive coating film is 100 parts by mass (dry weight). The conductive precoated aluminum alloy sheet, wherein the content of the wax in the conductive coating film is 0.05 parts by mass or more and 25 parts by mass or less. The conductive precoated aluminum alloy sheet according to any one of claims 1 to 6, wherein the silicate is lithium silicate, and a molar ratio of SiO ₂ / Li ₂ O in the silicate is 3. A conductive precoated aluminum alloy plate, characterized by being from 5 to 7.5. In conductive precoat aluminum alloy plate according to claim 1, said silicate is a sodium silicate, the molar ratio of SiO ₂ / Na ₂ O in the silicate is 0 A conductive pre-coated aluminum alloy plate, characterized in that it is from 5 to 4.0. The conductive precoated aluminum alloy sheet according to any one of claims 1 to 6, wherein the silicate is potassium silicate, and the molar ratio of SiO ₂ / K ₂ O in the silicate is 1. A conductive pre-coated aluminum alloy plate, characterized in that it is .8 to 3.7. In conductive precoat aluminum alloy plate according to claim 1, said silicate is an ammonium silicate, the molar ratio of SiO ₂ / NH ₃ in the silicate is 24 to 57. A conductive precoated aluminum alloy plate characterized by being 57.   In the electroconductive precoat aluminum alloy plate of any one of Claims 1-10, when measuring the electrical resistance of 20 surface parts from which the said electroconductive coating film differs by the acicular electrode method, 10 or more places A conductive precoated aluminum alloy plate characterized in that the electrical continuity is present at the surface portion and the average value of electrical resistance at the 20 surface portions is 10Ω or less.