JP2013212692A - Heat dissipating resin coated aluminum material, and production process therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat dissipating resin coated aluminum material excellent in conductivity and bending workability as well as in heat dissipation, and to provide its production process.SOLUTION: There are provided: a heat dissipating resin coated aluminum material that includes an aluminum material, a chemical conversion coating formed on both sides of the aluminum material and a resin coating of 0.4-1.9 μm in thickness which is formed on at least one surface of the chemical conversion coating, wherein the resin coating includes a coating material comprising a polyester resin having a benzene ring in its molecule and being 21,000-28,000 in number average molecular weight, a melamine resin, carbon black having a mean particle size of 115-140 nm, nickel and a liquid wax, and a production process thereof.

Description

  The present invention is used for casings and heat sinks of electronic parts that emit heat internally, household electrical appliances, etc., in addition to heat dissipation, resin-coated aluminum material excellent in conductivity, bending workability, corrosion resistance, and its It relates to a manufacturing method.

  Due to the downsizing and high performance and integration of electronic components incorporated in electronic devices, the temperature inside electronic devices rises. In order to prevent malfunction and life reduction of the electronic device due to this, it is an important issue to efficiently exhaust heat to the outside of the electronic device casing. For such problems, it is known that forced air cooling using a fan is more effective than natural air cooling. Specifically, an opening is provided in the electronic device casing, and a fan provided around the opening is operated to discharge heat generated inside the electronic device to the outside.

  However, this method still has a problem that moisture, dust, and the like easily enter the inside from the outside, and an electronic circuit inside the electronic device may be short-circuited. Then, in order to prevent the temperature rise in an electronic device, using natural air cooling is examined. In order to increase the air cooling efficiency by natural air cooling, surface treatment having high heat dissipation is performed using a material having high thermal conductivity. Specifically, as disclosed in Patent Documents 1 and 2, an aluminum material is used as a heat radiating material, and a heat radiating resin film is provided on the surface thereof.

  On the other hand, by using a resin-coated aluminum material as a material for the electronic device casing, the weight of the electronic device can be reduced. Furthermore, since the electronic equipment casing is required to have a grounding property and an electromagnetic wave shielding property, a device for imparting conductivity to the resin-coated aluminum material has been devised. Specifically, a conductive substance is contained in the resin film. Electronic equipment casings are required to have high-performance conductivity. Simply adding a conductive material to the resin film results in high electrical resistance. In some cases, it is possible to cope with exposure. Therefore, application of a thin film resin-coated aluminum material in which the insulating resin film is reduced as much as possible has been studied.

  The thin film resin-coated aluminum material has a problem that water, which is a corrosion-causing substance existing in the resin film, easily reaches the surface of the aluminum material and is easily corroded. In particular, when a conductive material is contained in the resin film, the resin film becomes discontinuous, water easily passes through the resin film, and the aluminum material is easily corroded. Also, when resin-coated aluminum materials for electronic equipment casings are press-molded overseas, they may be stored in a coiled state in a hot and humid environment, and resin-coated aluminum materials for such applications Is required to have excellent corrosion resistance.

  The heat-dissipating resin-coated aluminum material disclosed in Patent Document 1 has high emissivity and excellent heat dissipation as described in the examples. However, since the film thickness is as thick as 10 μm, the electrical resistance value is high (for example, 700Ω), and in recent years, there remains a problem that the electrical conductivity required for the electronic device casing cannot be satisfied. Furthermore, improvement in bending workability and corrosion resistance for the heat-dissipating resin-coated aluminum material has been demanded.

JP 2004-160979 A

  In view of the above problems and demands, an object of the present invention is to provide a heat-dissipating resin-coated aluminum material excellent in conductivity, bending workability and corrosion resistance in addition to heat dissipation, and a method for producing the same.

In order to solve the above problems, the present invention has the following configuration.
The first invention is an aluminum material, a chemical conversion film formed on both surfaces of the aluminum material, and a resin film formed on at least one surface of the chemical conversion film and having a thickness of 0.4 to 1.9 μm. The resin film is formed from a paint containing a thermosetting resin, carbon black having an average particle diameter of 115 to 140 nm, a specific surface area of 6 to 28 m ² / g, and nickel, The heat-dissipating resin-coated aluminum material was characterized in that the area occupation ratio on the surface of the resin film was 40 to 90%.

  A second invention according to claim 1 is formed on at least one surface of an aluminum material, a chemical conversion film formed on both surfaces of the aluminum material, and the chemical conversion film, and has a thickness of 0.4 to 1.9 μm. A resin film having a benzene ring in the molecule and having a number average molecular weight of 21000 to 28000, a melamine resin, and an average particle diameter of 115 to 140 nm. The heat-dissipating resin-coated aluminum material is formed from a paint containing carbon black, nickel, and liquid wax.

  According to a second aspect of the present invention, in claim 2, the arithmetic average roughness of the resin film surface is Ra (μm), the contour curve average length is RSm (μm), and Ra / RSm is 0.058 or less.

In 2nd invention, in Claim 3, the surface energy of the said resin film surface was 60x10 < ^-3 > J / m < ² > or less. According to a fourth aspect of the present invention, in the paint, the melamine resin is 5 to 60 parts by weight and the carbon black is 15 to 35 parts by weight with respect to 100 parts by weight of the polyester resin. In terms of proportion, nickel was blended in a proportion of 30 to 100 parts by weight, and liquid wax was blended in a proportion of 1 to 15 parts by weight. Furthermore, in claim 5 of the second invention, the area occupancy of the carbon black on the surface of the resin film is 50 to 70%.

About the manufacturing method of 1st invention, in the manufacturing method of the heat radiation resin coating | coated aluminum material provided with the resin film formed on the at least one surface of an aluminum material, the process of performing a chemical conversion treatment on both surfaces of an aluminum material, A curable resin, carbon black having an average particle size of 115 to 140 nm, a specific surface area of 6 to 28 m ² / g, and a dispersant are added to an organic solvent, and these additives are dispersed to reduce the dispersed particle size to 10 μm or less. And a step of preparing a paint by further adding and dispersing nickel therein, a step of applying the paint to at least one surface of the aluminum material subjected to the chemical conversion treatment, and a maximum reached plate temperature of 180 to 300 ° C. A step of baking and curing the applied paint under a baking time of 15 to 80 seconds to form a resin film having a thickness of 0.4 to 1.9 μm. Mukoto was the manufacturing method of the heat radiating resin coated aluminum material according to claim.

  About the manufacturing method of 2nd invention, in Claim 6, in the manufacturing method of the heat dissipation resin covering aluminum material according to any one of claims 1-5, the process of performing chemical conversion treatment on both sides of an aluminum material, Carbon black having an average particle diameter of 115 to 140 nm and a dispersing agent are added to an organic solvent, and these additives are dispersed therein. The additive has a benzene ring in the molecule and has a number average molecular weight of 21000 to 28000. And adding a polyester resin having a melamine resin, a melamine resin, and a liquid wax to a dispersion particle size of 10 μm or less, further adding and dispersing nickel therein to prepare a paint, and performing the chemical conversion treatment. A step of applying the paint to at least one surface of the finished aluminum material, and a condition that a baking temperature is 20 to 80 seconds at a maximum reached plate temperature of 200 to 250 ° C. The applied coating by baking curing, and a step of forming a resin film having a thickness of 0.4～1.9Myuemu, the method for producing a heat radiation resin coated aluminum material which comprises a.

  In the first invention, carbon black having a specific average particle diameter and specific surface area is used, and further, a paint is prepared under specific dispersion conditions, and is applied and baked and hardened. The area occupancy on the surface of the black resin film can be in a specific range. Thereby, in addition to the heat dissipation of the resin-coated aluminum material, good conductivity and bending workability are obtained.

  In the second invention, since a high molecular weight polyester-based resin is used as the thermosetting resin, the entangled structure of the resin increases, the liquid wax is fixed in the resin film, and the diffusion of moisture causing corrosion is caused. Due to the delay, the corrosion resistance is improved. In particular, the corrosion resistance after bending is improved. In addition to heat dissipation, good conductivity, bending workability and corrosion resistance can be obtained by dispersing nickel and coarse carbon black in a resin film obtained by curing high molecular weight polyester resin with melamine resin by an appropriate method. .

It is sectional drawing which shows typically the apparatus for evaluating the heat dissipation of the resin-coated aluminum material which concerns on this invention. It is a schematic diagram showing the spreading | diffusion of the water | moisture content in the powdery wax and liquid wax which exist in the resin film of the resin coating aluminum material which concerns on this invention.

A. Heat-dissipating resin-coated aluminum material according to the first invention The first invention according to the present invention is an aluminum material, a chemical conversion film formed on both surfaces thereof, and is formed on one surface of 0.4 to 1.9 μm. A heat-dissipating resin-coated aluminum material. The resin film is formed from a paint containing a thermosetting resin, carbon black having an average particle diameter of 115 to 140 nm and a specific surface area of 6 to 28 m ² / g, and nickel. The area occupation ratio of the carbon black on the resin film surface is 40 to 90%.

B. Aluminum material The material of the aluminum material is not particularly limited, but it is suitable to have sufficient strength to form and hold the case, and to have sufficient press formability during drawing and bending. Used for. Examples of such aluminum materials include 1000 series, 3000 series and 5000 series aluminum alloys. As the shape of the aluminum material, a plate material having a thickness of 0.1 to 2.5 mm is preferably used.

C. Chemical conversion film A chemical conversion film is formed on both surfaces of the aluminum material. Examples of the chemical conversion film include reaction type and coating type chemical conversion films. Either a reactive type or a coating type chemical conversion film may be used, and it is not particularly limited. It is preferable to use a reactive chemical conversion film having good adhesion to both the aluminum material and the resin film. As the reactive chemical conversion film, a film formed with a treatment liquid such as phosphate chromate, chromate chromate, zirconium phosphate, titanium phosphate or the like is preferably used. In particular, a phosphoric acid chromate film is preferable, and the corrosion resistance of the aluminum material can be greatly enhanced. The phosphate chromate film preferably has a Cr content of 10 to 50 mg / m ² . If the Cr content is less than 10 mg / m ² , the corrosion resistance may be inferior, and if it exceeds 50 mg / m ² , the corrosion resistance may be inferior.

D. Resin film D-1. Film thickness The film thickness of the resin film is 0.4 to 1.9 µm. When the film thickness is less than 0.4 μm, the heat dissipation is inferior. When the film thickness exceeds 1.9 μm, the convex portions on the surface of the aluminum material are covered with the resin film and are difficult to be exposed, resulting in poor conductivity. In addition, the film thickness said here is a thing after baking drying.

D-2. Structure of resin film D-2-1. Thermosetting resin The thermosetting resin used in the present invention is not particularly limited. For example, an epoxy resin, a fluorine resin, an acrylic resin, a polyester resin crosslinked with a melamine resin, or a polyester crosslinked with an isocyanate resin. A resin or the like can be used. Radiant heat from an electronic device is effective in improving heat dissipation by improving thermal radiation in an infrared region having a peak at a wavelength of 8 to 10 μm according to Planck's law. Therefore, in particular, by using a polyester resin crosslinked with a melamine resin, such heat dissipation can be improved. According to Kirchhoff's law, a material having high thermal emissivity and thermal absorption rate and having high infrared absorptivity can be said to be a material having high infrared emissivity.

A polyester resin crosslinked with a melamine resin will be described. As the polyester resin, alkyd resin, unsaturated polyester resin, modified alkyd resin and the like are used. The alkyd resin has a skeleton of a condensate of a polybasic acid such as phthalic anhydride and a polyhydric alcohol such as glycerin, which is modified with fatty acid fats and oils. Depending on the type and content of the fats and oils used, the oils are classified into short oil alkyd resins, medium oil alkyd resins, long oil alkyd resins and super long oil alkyd resins. An unsaturated polyester resin is synthesized by esterifying an unsaturated polybasic acid or a saturated polybasic acid and a glycol. As the polybasic acid, phthalic anhydride, isophthalic acid, terephthalic acid and adipic acid are used, and as the glycols, propylene glycol is often used. As the modified alkyd resin, those modified with a polymerizable monomer such as natural resin, phenol resin or styrene are used.

As the melamine-based resin, a methylated melamine-based resin, a butylated melamine-based resin, or the like is used, and a methylated melamine-based resin is preferable from the viewpoint of processability. The melamine resin has good infrared radiation (absorbability) in a wide infrared wavelength range, and is preferably blended in an amount of 10 to 50 parts by weight, more preferably 20 to 40 parts by weight with respect to 100 parts by weight of the polyester resin. Is done. When the blending ratio of the melamine-based resin is less than 10 parts by weight, the degree of crosslinking of the film becomes insufficient, and bending workability and other general physical properties of the coating film may be deteriorated. On the other hand, when the blending ratio of the melamine resin exceeds 50 parts by weight, the crosslinking reaction proceeds too much, the coating film becomes too hard, and the bending workability may be lowered.

D-2-2. Carbon black Carbon black is contained as an essential component for imparting heat dissipation to the resin film by infrared radiation. Carbon black is a substance of fine black powder produced by pyrolyzing a hydrocarbon raw material by a channel method, a furnace method, a thermal decomposition method, an acetylene method or the like. In the channel method, natural gas is mainly used as a raw material, which is incompletely combusted from a number of burner chips in the combustion chamber, and is made to collide with an iron channel at an appropriate height to deposit carbon black, which is collected. It is a method to do. The furnace method is a method in which a raw material is thermally decomposed in a state where oxygen is insufficient in a furnace lined with refractory bricks. The thermal decomposition method is a method in which the supply of air is completely cut off and heat is supplied from another to perform thermal decomposition. The acetylene method is a method by thermal decomposition of acetylene gas.

The method for producing carbon black used in the present invention is not particularly limited as long as carbon black having an average particle diameter of 115 to 140 nm and a specific surface area of 6 to 28 m ² / g can be obtained. If the average particle size is less than 115 nm, the concentration of carbon black in the resin film cannot be sufficiently increased, and heat dissipation is inferior. On the other hand, when the thickness exceeds 140 nm, carbon black having a large particle diameter is present around the nickel, so that discontinuous portions increase, and water easily penetrates into the resin film, resulting in poor corrosion resistance. The average particle size of carbon black is measured by electron microscopy.

The specific surface area is a physical quantity governed by the particle diameter and the number of pores, and what is used in the present invention is a nitrogen adsorption surface area measured by the BET method. The specific surface area decreases as the particle size increases and the number of pores decreases. On the other hand, the smaller the particle size and the larger the number of pores, the larger the specific surface area. When the specific surface area is less than 6 m ² / g, carbon black having a large particle diameter is present around the nickel, so that it becomes a starting point of cracking and bending workability is poor. On the other hand, when the specific surface area exceeds 28 m ² / g, the number of pores increases, so that carbon black tends to aggregate around nickel. As a result, the distribution state of carbon black in the resin film becomes non-uniform, and the bending workability is poor.

  The carbon black is preferably added in an amount of 15 to 35 parts by weight with respect to 100 parts by weight of the thermosetting resin. If it is less than 15 parts by weight, the absolute amount of the carbon black resin film is insufficient, and the heat dissipation may be inferior. On the other hand, if it exceeds 35 parts by weight, uniform film formation may not be obtained.

D-2-3. Area Occupancy Ratio of Carbon Black on Resin Film Surface The area occupancy ratio of carbon black on the resin film surface is 40 to 90%. If the area occupancy is less than 40%, the dispersion state of the carbon black is uneven and bending workability is poor. On the other hand, if it exceeds 90%, the carbon black aggregates around the nickel, and the distribution of the carbon black in the resin film becomes non-uniform, resulting in poor bending workability.

D-2-4. Nickel is contained as an essential component for imparting conductivity to the nickel resin film. There are various kinds of nickel, such as sphere, chain, and scaly, and the nickel is not particularly limited, but the chain and scaly are particularly preferable from the viewpoints of workability and conductivity. Nickel used is a mixture of one or more of the above types.

  The average particle diameter of nickel is preferably 0.5 to 20 μm. When the average particle size is less than 0.5 μm, the conductivity is poor. In order to eliminate this, it is necessary to increase the amount of nickel, which increases the cost. On the other hand, when it exceeds 20 μm, it becomes a starting point of cracking and bending workability is lowered. The average particle diameter of nickel is measured by the fish-subsieve method. As for the addition amount of nickel, 30-100 weight part is preferable with respect to 100 weight part of thermosetting resins. If it is less than 30 parts by weight, the conductivity is inferior. On the other hand, if it exceeds 100 parts by weight, film formation becomes difficult.

E. Manufacturing method of heat-dissipating resin-coated aluminum material E-1. Chemical conversion treatment step Before the resin film is formed on the surface of the aluminum material, chemical conversion treatment is performed on both surfaces thereof. The chemical conversion treatment is performed by spraying a predetermined chemical conversion treatment liquid on the aluminum material or immersing the aluminum material in the treatment liquid at a predetermined temperature for a predetermined time. Commercially available chemical conversion treatment solutions such as phosphate chromate, chromate chromate, zirconium phosphate, and titanium phosphate can be used.

  Before the chemical conversion treatment, in order to remove dirt on the surface of the aluminum material or to adjust the surface properties, the aluminum plate is acid-treated (washed) with sulfuric acid, nitric acid, phosphoric acid, etc., or caustic soda, It is desirable to perform alkali treatment (washing) with sodium phosphate, sodium silicate, or the like. Surface treatment by such cleaning is also performed by spraying a predetermined surface treatment liquid on the aluminum plate or immersing the aluminum plate in the treatment liquid at a predetermined temperature for a predetermined time.

E-2. Paint preparation step The thermosetting resin and carbon black are added to an organic solvent, and a dispersant is further added to prepare a dispersion solution. And the additive in a dispersion solution is disperse | distributed so that a dispersion particle size may be 10 micrometers or less. The dispersion time may be selected as appropriate, but usually 30 to 180 minutes is preferable. Next, nickel is further added to and dispersed in the dispersion solution to prepare a coating material.

  Organic solvents include benzene, toluene, methyl alcohol, ethyl alcohol, ethyl acetate, butyl acetate, cellosolve, butyl cellosolve, 1,4-dioxane, tetrahydrofuran, cyclohexane, isophorone, isobutyl alcohol, xylene, ethylbenzene, methyl ethyl ketone, diacetone alcohol, Ethylene glycol monobutyl ether, high boiling aromatic naphtha, etc. are used. 50 to 600 g of the total amount of the thermosetting resin and carbon black is dispersed in 1 liter of an organic solvent.

  As the dispersant, an anionic compound, a cationic compound, a nonionic compound, a polymer compound, or the like is used. As the anionic compound, a sulfate-based compound, a sulfonate-based compound, a phosphate-based compound, or the like is used. Examples of the cationic compound include amines, amine salts, ammonium salts, and the like. Nonionic compounds include esters, ethers, phenols and the like. As the polymer compound, there are many types including various polymers singly or as a mixture. The dispersant is added in an amount of 2 to 40 parts by weight with respect to 100 parts by weight of the total amount of the thermosetting resin and carbon black.

  The dispersion method of the additive in the dispersion solution and the dispersion method of the nickel added to the dispersion solution include a stirring-type dispersion device, a high-speed rotary shearing-type dispersion device, a mill-type dispersion device, and a high-pressure jet dispersion. A method using an apparatus or an ultrasonic dispersion apparatus is used. It is preferable to use a stirring type dispersing device, a high-speed rotational shearing type dispersing device, a mill type dispersing device, and a high-pressure jet type dispersing device.

  The agitation type dispersion device stirs the paint using propeller blades, turbine blades, paddle blades, toothed disk blades, etc., and the carbon black due to the solvent velocity gradient near the blades or the collision of carbon black with the blades. Is dispersed. A high-speed rotary shear type dispersion device rotates a stirring blade at a high speed, and a fixed ring is provided on the outer side of the stirring blade to realize a high shear field in the gap between the blade and the fixed ring. It is to prevent. The carbon black is moderately dispersed by passing through the gap between the wing and the fixing.

  Examples of the mill type dispersion device include a ball mill, a bead mill, a colloid mill, and a roll mill. In the ball mill, a large number of hard balls in the rotating container move, and carbon black is dispersed by collision between the hard balls generated at that time. In the bead mill, hard balls placed in a multistage stirring tank move, and carbon black is dispersed by collision between the hard balls generated at that time. In the colloid mill, one of the upper and lower two disks (grinding stones) is rotated, and carbon black is dispersed by a high shear field formed by the disk gap. In the roll mill, carbon black is dispersed by a shear field generated in a gap between rotating cylindrical rolls. In a high-pressure injection type dispersion apparatus, carbon black is dispersed by applying high pressure to a suspension and injecting the suspension onto a fixed plate at an outlet at high speed.

  If the dispersion time is less than 30 minutes, the carbon black may not be uniformly dispersed, and in that case, the bending workability is poor. If it exceeds 180 minutes, the thermosetting resin may be deteriorated, and in that case, the bending workability is inferior. When the dispersed particle size exceeds 10 μm, the carbon black forms an aggregate and the bending workability is inferior.

  The paint may contain an appropriate amount of wax, leveling agent, anti-waxing agent, matting agent, etc., if necessary.

E-3. Application process The paint is applied to one surface of the chemically treated aluminum material. As a coating method, a roll coating method is preferable. In the roll coat method, the paint is usually stored in a pan, and the paint is picked up from the pan by a pick-up roll and transferred to an applicator roll. The paint is then transferred to the material. The material is conveyed using a backup roll. The nip pressure and the paint viscosity between the pick-up roll and the applicator roll are appropriately adjusted so that the film thickness after baking and drying is 0.4 to 1.9 μm.

E-4. Step of forming resin film by baking and curing The applied paint is baked and cured under the conditions that the maximum plate temperature is 180 to 300 ° C. and the baking time is 15 to 80 seconds. A hot stove is preferably used for baking. By adjusting the temperature in the hot air furnace and the time for passing through the furnace, the bake hardening condition is achieved. When the maximum plate temperature is less than 180 ° C. or the baking time is less than 15 seconds, the thermosetting resin is not sufficiently cured and the bending workability is poor. On the other hand, when the maximum plate temperature exceeds 300 ° C. or the baking time exceeds 80 seconds, the thermosetting resin starts to deteriorate and the bending workability is poor.

F. Heat-dissipating resin-coated aluminum material according to the second invention Next, a second invention according to the present invention is formed on an aluminum material, a chemical conversion film formed on both surfaces thereof, and one surface thereof. A heat-dissipating resin-coated aluminum material provided with a resin film having a thickness of 1.9 μm. The resin film has a benzene ring in the molecule and a polyester resin having a number average molecular weight of 21000 to 28000, a melamine resin, carbon black having an average particle diameter of 115 to 140 nm, nickel, It is formed from a paint containing liquid wax. In the following, differences from the first invention will be described in detail. About the film thickness of an aluminum material, a chemical conversion film, and a resin film, it is the same as 1st invention.

G. Resin film G-1. Structure of resin film G-1-1. Thermosetting resin In the thermosetting resin of the second invention, a polyester resin having a benzene ring in the molecule and having a number average molecular weight of 21000 to 28000 is cured by crosslinking with a melamine resin. Is used. The polyester resin crosslinked with the melamine resin will be described in detail below. The presence of a benzene ring in the molecule of the polyester resin can impart hydrophobicity to the resin film. As a result, even if water permeates, it repels it, thereby improving the corrosion resistance. Polyester resins are synthesized by reacting polybasic acids and polyhydric alcohols, and since they have a benzene ring in the molecule, polybasic acids include benzene-1,2-dicarboxylic acid, benzene-1,3. -Dicarboxylic acid, benzene-1,4-dicarboxylic acid, etc. are used. As the polyhydric alcohol, propylene glycol or the like is used. The number average molecular weight of the polyester resin obtained by synthesis is preferably 21000 to 28000. Such a high molecular weight polyester resin generally has a drawback that the crosslinking point is reduced because the number of crosslinking points is reduced, and the strength of the resin film tends to be insufficient. In the present invention, such a high molecular weight polyester resin is used. In order to compensate for the disadvantage, the resin film is formed into a thin film and, as will be described later, nickel is added as an essential constituent of the resin film. The film is designed to exhibit sufficient performance as a scratch resistance of the film.

Since such a high molecular weight polyester-based resin is used, the entangled structure of the resin is increased, and water and oxygen that cause corrosion are difficult to permeate and the corrosion resistance is improved. In particular, the corrosion resistance after bending is improved. Moreover, since there are few low molecular weight components, workability is also improved. Thus, in this invention, since high molecular weight polyester-type resin is used, there is no resin film crack after bending. In addition, the thickness of the resin film at the bent part is thinner than other parts, but because the entanglement structure of the resin is large, water and oxygen that cause corrosion are difficult to permeate, so the corrosion resistance is improved. . When the number average molecular weight of the polyester resin is less than 21,000, the corrosion resistance after bending may be inferior. On the other hand, if it exceeds 28000, the viscosity of the paint increases and the appearance of the paint may be poor.

As the melamine-based resin, methylated melamine resin, butylated melamine resin and the like are used, and methylated melamine resin is preferable from the viewpoint of processability. The melamine-based resin has good infrared radiation (absorptivity) in a wide infrared wavelength range, and is preferably blended at a rate of 5 to 60 parts by weight with respect to 100 parts by weight of the polyester resin. More preferably, it is blended. If the blending ratio of the melamine-based resin is less than 5 parts by weight, the degree of crosslinking of the resin film may be insufficient and the corrosion resistance may be inferior. On the other hand, when the blending ratio of the melamine resin exceeds 60 parts by weight, self-crosslinking of the melamine resin proceeds and water tends to penetrate between the polyester resin and the corrosion resistance may be inferior.

G-1-2. Carbon Black There is no particular limitation on the method for producing carbon black used in the present invention, as long as carbon black having an average particle diameter of 115 to 140 nm can be obtained. Unlike the carbon black used in the first invention, there is no restriction on the specific surface area. The average particle diameter is in the above range as in the first invention. The amount of carbon black added to the thermosetting resin is also 15 to 35 parts by weight with respect to 100 parts by weight of the thermosetting resin, as in the first invention. The reason why this range is preferable is the same as in the first invention. It is. The average particle diameter is also measured as in the first invention.

G-1-3. Unlike the first invention, the area occupation ratio of the carbon black on the resin film surface is not limited. However, if the area occupancy is less than 50%, preferably 50 to 70%, heat dissipation and corrosion resistance may be inferior. On the other hand, if it exceeds 70%, the conductivity may be inferior.

G-1-4. Nickel The nickel to be added is the same as that used in the first invention with respect to the type, average particle diameter, and amount added to the thermosetting resin.

G-1-5. Liquid wax Liquid wax is contained as an essential component for imparting lubricity to the resin film. The liquid wax has a melting point of room temperature or lower, and monohydric alcohol fatty acid ester, methyl laurate, methyl myristate, etc. are used. The liquid wax exists in the resin film in a liquid state, and when it exists at the interface between the resin film and the chemical conversion film, the adhesion of the resin film is lowered and the corrosion resistance is lowered. Thus, the liquid wax present at the interface between the resin film and the chemical conversion film causes corrosion. In the present invention, since a high molecular weight polyester-based resin is used as the thermosetting resin, the intermolecular force acts strongly and the entanglement of the resin increases. As a result, the liquid wax is held not in the interface between the resin film and the chemical conversion film but in the entangled resin film, so that the adhesion of the resin film does not deteriorate.

  Moisture can also cause corrosion. Since the specific gravity of water is 1 and the specific gravity of the resin film is 1.2 to 1.3, water is unevenly distributed on the upper side of the resin film. However, in the resin film used in the present invention, the thermosetting resin is intertwined in a chain shape. In such an entangled structure, when a certain amount of time elapses, moisture diffuses in the resin film and then also in the chemical conversion film and reaches the surface of the aluminum material. This moisture can cause corrosion of the aluminum material. In the present invention, liquid wax is present in the resin film. As shown in FIG. 2 (b), when moisture approaches the liquid wax 5, the moisture does not diffuse in the liquid wax having no orientation in the crystal structure, but diffuses as D2 along the vicinity of the surface of the liquid wax 5. To do. In contrast, general-purpose powdery waxes have a directional crystal structure such as a lamellar structure. In this case, as shown in FIG. 2A, water diffuses in the powdery wax 4 as D1. The liquid wax is present in the resin film in a size of about 0.6 μm, and the powdery wax is also about the same size on average. Then, since the liquid wax has a longer moisture diffusion distance than the powder wax, it takes a long time for the moisture to reach the aluminum surface. As a result, the corrosion resistance is improved when the liquid wax is contained as compared with the powder wax.

  Since powder wax is easily melted and particles are fused, the particle size distribution in the resin film tends to exist more on the larger diameter side than liquid wax. Therefore, the density in the resin film is reduced even with the same blending amount as the liquid wax. As a result, moisture easily diffuses in the powdery wax with many gaps, and the corrosion resistance decreases. This is remarkable in the corrosion resistance after bending. Since the resin film is stretched by bending, the resin film thickness near the apex of the bent portion becomes thinner than that after baking and drying. In the case of powdery wax, the wax itself is deformed together with the resin film, and is sometimes cut. Since the gap portion where water diffuses increases due to such deformation or cutting of the wax, moisture caused by corrosion is easily diffused. On the other hand, the liquid wax itself deforms with the deformation of the resin film, but since it is liquid, it is difficult to be cut and the continuity is easily maintained. As a result, compared to powdered wax, moisture is less likely to diffuse therein and corrosion resistance is improved.

  The liquid wax is preferably added in an amount of 1 to 15 parts by weight with respect to 100 parts by weight of the thermosetting resin. If it is less than 1 part by weight, the lubricity and corrosion resistance of the resin film may be inferior, and if it exceeds 15 parts by weight, the conductivity may be inferior.

H. Ra / RSm
In the second invention, Ra / RSm is preferably 0.058 or less, where Ra (μm) is the arithmetic mean roughness of the resin film surface and RSm (μm) is the average contour curve length. Ra and RSm are determined by analyzing the surface of the resin film with a laser microscope, for example, in accordance with JISB0601. Here, the Ra / RSm index represents the distribution of convex portions on the surface of the resin film, and the smaller the height of the convex portions and the smaller the interval between the convex portions, the smaller the value. Since the film thickness of the resin film used in the present invention is thin, nickel having a large average particle diameter forms a convex portion. When Ra / RSm is 0.058 or less, since nickel is appropriately dispersed in the resin film, carbon black is sufficiently present in the resin film, and the heat dissipation is excellent. On the other hand, when Ra / RSm exceeds 0.058, a large amount of nickel is distributed in the resin film and the resin content is reduced, resulting in poor heat dissipation. Ra is preferably 0.4 to 1.2 μm or less, and RSm is preferably 10.4 to 13.0 μm.

I. Surface energy The surface energy of the resin film surface is preferably 60 × 10 ⁻³ J / m ² or less. When it exceeds 60 × 10 ⁻³ J / m ² , lubricity may be insufficient and workability may be inferior.

J. et al. Production method of heat-dissipating resin-coated aluminum material The chemical conversion treatment step and the cleaning of acid and alkali are the same as in the first invention.

J-1. Paint preparation step The carbon black and the dispersant are added to an organic solvent to prepare a dispersion solution. Then, the additive in the dispersion solution is dispersed. 2 to 35 g of a dispersant and 5 to 100 g of carbon black are dispersed in 1 liter of an organic solvent. The dispersion time may be selected as appropriate, but usually 30 to 180 minutes is preferable. Next, the above-described polyester resin, melamine resin, and liquid wax are added and dispersed in this dispersion solution so that the dispersed particle size is 10 μm or less. The addition amount of the polyester resin is based on the aforementioned weight ratio with the carbon black in the dispersion solution, and the addition amount of the melamine resin and the liquid wax is based on the weight ratio of the aforementioned polyester resin. The dispersion time may be selected as appropriate, but usually 30 to 180 minutes is preferable. Nickel is further added to this dispersion solution, and this is dispersed to prepare a coating material. The amount of nickel added is based on the aforementioned weight ratio with the polyester resin in the dispersion. The dispersion time may also be selected as appropriate, but usually 30 to 180 minutes is preferable. In addition, the same thing as 1st invention is used for a dispersing agent and an organic solvent. Further, the dispersion apparatus and dispersion conditions used for dispersion are the same as in the first invention. If necessary, a leveling agent, an anti-bacterial agent, a matting agent and the like may be contained.
The disadvantages when the dispersion time is less than 30 minutes or exceeds 180 minutes, and when the dispersion particle size exceeds 10 μm are the same as in the first invention.

J-2. Application process and resin film formation process by baking and curing The application process is the same as in the first invention. In the process of forming the resin film by baking and curing, the applied paint is baked and cured under the conditions that the maximum plate temperature is 200 to 250 ° C. and the baking time is 20 to 80 seconds. As in the first invention, a hot stove is suitably used for baking. By adjusting the temperature of the hot air furnace and the time for passing through the inside of the furnace, the bake hardening condition is achieved. When the maximum plate temperature is less than 200 ° C. or the baking time is less than 20 seconds, the thermosetting resin is not sufficiently cured. As a result, water easily diffuses in the resin film, resulting in poor corrosion resistance. On the other hand, when the maximum plate temperature exceeds 250 ° C. or the baking time exceeds 80 seconds, the thermosetting resin is deteriorated and the entangled structure of the resin cannot be sufficiently obtained. As a result, water easily diffuses in the resin film, resulting in poor corrosion resistance. In order to reliably achieve the state in which the liquid wax is contained in the resin film, it is preferable that the maximum attainment plate temperature is 10 ° C. or lower than the boiling point of the liquid wax.

Below, the 1st invention concerning the present invention is explained in detail based on an example and a comparative example.
(Examples 1-6 and Comparative Examples 1-6)
100 parts by weight of thermosetting resin in which 20 parts by weight of melamine resin (methylated melamine resin) is blended with 100 parts by weight of polyester resin (alkyd resin), and 25 parts by weight of carbon black shown in Table 1 are used as an organic solvent. (To a mixed solvent of toluene and cyclohexanone). Further, 10 parts by weight of a dispersant (nonionic compound) was added thereto. The amount of the organic solvent was 1 liter with respect to a total amount of 125 g of the thermosetting resin and carbon black. The solution thus prepared was stirred for 80 minutes with a stirring type dispersing device equipped with a propeller blade. The dispersion particle size of the obtained dispersion solution was 8 μm. Furthermore, 40 parts by weight of nickel (scale-like) was added to 100 parts by weight of the thermosetting resin, and stirred with a stirrer equipped with a toothed disk blade to prepare a coating material.

  As the aluminum material, an aluminum plate (material: JIS A5052) having a thickness of 0.6 mm was used. The both surfaces were degreased with a commercially available aluminum degreasing agent and washed with water. Next, chemical conversion treatment was performed on both surfaces of the aluminum plate with a commercially available phosphoric acid chromate treatment solution. Then, it applied to one surface of the aluminum plate which carried out the chemical conversion treatment of the said coating material by the roll coat system, and baked with the hot air oven, and produced the resin coating aluminum material. As for the baking conditions, the maximum plate temperature was 240 ° C. and the baking time was 50 seconds.

(Example 7)
100 parts by weight of a thermosetting resin in which 20 parts by weight of a melamine resin (methylated melamine resin) is blended with 100 parts by weight of a polyester resin (alkyd resin), and 20 parts by weight of carbon black shown in Table 1 are used as an organic solvent. (To a mixed solvent of toluene and cyclohexanone). Further, 12 parts by weight of a dispersant (nonionic compound) was added thereto. The amount of the organic solvent was 1 liter with respect to a total amount of 135 g of the thermosetting resin and carbon black. The solution thus prepared was stirred for 40 minutes with a stirring type dispersion apparatus equipped with a propeller blade. The dispersion particle size of the obtained dispersion solution was 9 μm. Furthermore, 30 parts by weight of nickel (scale-like) was added to 100 parts by weight of the thermosetting resin, and stirred with a stirrer equipped with a toothed disk blade to prepare a coating material.

  As the aluminum material, an aluminum plate (material: JIS A5052) having a thickness of 0.6 mm was used. The both surfaces were degreased with a commercially available aluminum degreasing agent and washed with water. Next, chemical conversion treatment was performed on both surfaces of the aluminum plate with a commercially available phosphoric acid chromate treatment solution. Then, it applied to one surface of the aluminum plate which carried out the chemical conversion treatment of the said coating material by the roll coat system, and baked with the hot air oven, and produced the resin coating aluminum material. The baking conditions were a maximum reached plate temperature of 182 ° C. and a baking time of 78 seconds.

(Invention Example 8)
100 parts by weight of thermosetting resin in which 20 parts by weight of melamine resin (methylated melamine resin) is blended with 100 parts by weight of polyester resin (alkyd resin) and 30 parts by weight of carbon black shown in Table 1 (To a mixed solvent of toluene and cyclohexanone). Further, 13 parts by weight of a dispersant (nonionic compound) was added thereto. The amount of the organic solvent was 1 liter with respect to a total amount of 127 g of the thermosetting resin and carbon black. The solution thus prepared was stirred for 160 minutes with a stirring type dispersion apparatus equipped with a propeller blade. The dispersion particle size of the obtained dispersion solution was 5 μm. Further, 80 parts by weight of nickel (scale-like) was added to 100 parts by weight of the thermosetting resin, and the mixture was stirred with a stirrer equipped with a toothed disk blade to prepare a paint.

  As the aluminum material, an aluminum plate (material: JIS A5052) having a thickness of 0.6 mm was used. The both surfaces were degreased with a commercially available aluminum degreasing agent and washed with water. Next, chemical conversion treatment was performed on both surfaces of the aluminum plate with a commercially available phosphoric acid chromate treatment solution. Then, it applied to one surface of the aluminum plate which carried out the chemical conversion treatment of the said coating material by the roll coat system, and baked with the hot air oven, and produced the resin coating aluminum material. The baking conditions were a maximum reached plate temperature of 296 ° C. and a baking time of 16 seconds.

(Comparative Example 7)
100 parts by weight of a thermosetting resin in which 20 parts by weight of a melamine resin (methylated melamine resin) is blended with 100 parts by weight of a polyester resin (alkyd resin), and 20 parts by weight of carbon black shown in Table 1 are used as an organic solvent. (To a mixed solvent of toluene and cyclohexanone). Further, 11 parts by weight of a dispersant (nonionic compound) was added thereto. The amount of the organic solvent was 1 liter with respect to a total amount of 134 g of the thermosetting resin and carbon black. The solution thus prepared was stirred for 10 minutes with a stirring type dispersion apparatus equipped with a propeller blade. The dispersion particle size of the obtained dispersion solution was 12 μm. Further, 50 parts by weight of nickel (scale-like) was added to 100 parts by weight of the thermosetting resin, and the mixture was stirred with a stirrer equipped with a toothed disk blade to prepare a paint.

  As the aluminum material, an aluminum plate (material: JIS A5052) having a thickness of 0.6 mm was used. The both surfaces were degreased with a commercially available aluminum degreasing agent and washed with water. Next, chemical conversion treatment was performed on both surfaces of the aluminum plate with a commercially available phosphoric acid chromate treatment solution. Then, it applied to one surface of the aluminum plate which carried out the chemical conversion treatment of the said coating material by the roll coat system, and baked with the hot air oven, and produced the resin coating aluminum material. The baking conditions were a maximum reached plate temperature of 170 ° C. and a baking time of 10 seconds.

(Comparative Example 8)
100 parts by weight of thermosetting resin in which 20 parts by weight of melamine resin (methylated melamine resin) is blended with 100 parts by weight of polyester resin (alkyd resin) and 30 parts by weight of carbon black shown in Table 1 (To a mixed solvent of toluene and cyclohexanone). Further, 14 parts by weight of a dispersant (nonionic compound) was added thereto. The amount of the organic solvent was 1 liter with respect to a total amount of 133 g of the thermosetting resin and carbon black. The solution thus prepared was stirred for 200 minutes with a stirring type dispersion apparatus equipped with a propeller blade. The dispersion particle size of the obtained dispersion solution was 4 μm. Further, 50 parts by weight of nickel (scale-like) was added to 100 parts by weight of the thermosetting resin, and the mixture was stirred with a stirrer equipped with a toothed disk blade to prepare a paint.

  As the aluminum material, an aluminum plate (material: JIS A5052) having a thickness of 0.6 mm was used. The both surfaces were degreased with a commercially available aluminum degreasing agent and washed with water. Next, chemical conversion treatment was performed on both surfaces of the aluminum plate with a commercially available phosphoric acid chromate treatment solution. Then, it applied to one surface of the aluminum plate which carried out the chemical conversion treatment of the said coating material by the roll coat system, and baked with the hot air oven, and produced the resin coating aluminum material. The baking conditions were a maximum reached plate temperature of 320 ° C. and a baking time of 95 seconds.

The average particle size of carbon black was measured by electron microscopy, and the average particle size of nickel was measured by Fish-Subsieve method. The specific surface area of carbon black was measured by the BET method using nitrogen adsorption. Moreover, as a result of measuring the film amount of the chemical film formed by the above-described method using a fluorescent X-ray analyzer, the chromium amount was 30 mg / m ² .

  The area occupation ratio of carbon black on the surface of the resin film was measured with a scanning electron microscope. In the secondary electron image obtained at a magnification of 1000 times that of a scanning electron microscope, the area where carbon black was present was calculated by subjecting the same visual field to elemental analysis and performing image processing on the portion where carbon was strongly detected. The average area occupancy obtained by measuring 10 fields of view was determined.

  Table 1 shows the resin film thickness, the average particle diameter of carbon black, the specific surface area, and the area occupancy rate for the samples of the resin-coated aluminum materials produced in Invention Examples 1-8 and Comparative Examples 1-8. Furthermore, Table 1 also shows the results of evaluation of bending workability, conductivity, and heat dissipation by the following methods. In the evaluation results, ○, ○ △, and Δ were accepted, and x was rejected.

<Bending workability>
For the bending workability, 180 ° 2T bending or 3T bending was performed with the resin film surface of the sample facing outside, and cracking of the resin film was visually observed. The evaluation criteria for cracks are as follows.
○: No resin film cracked △: Small resin film cracked but usable ×: Large resin film cracked not usable

Furthermore, after observing the crack, the cellophane tape was brought into close contact with the bent portion of the resin film, and the degree of peeling of the resin film when the tape was abruptly peeled was observed as adhesion. The evaluation criteria for adhesion are as follows.
○: No peeling ×: With peeling

<Conductivity>
For electrical conductivity, an electric resistance value was measured by bringing a silver probe (diameter 5 mm, tip 2.5R) into contact with the resin film surface of the sample under a load of 80 g by a four-terminal method. The evaluation criteria for conductivity are as follows.
○: 4Ω or less ○ △: Over 4Ω, 6Ω or less △: Over 6Ω, 10Ω or less ×: Over 10Ω

<Heat dissipation>
The heat dissipation was evaluated by preparing a casing using a resin-coated aluminum material and measuring the casing surface temperature. As shown in FIG. 1, a housing 3 having a bottom surface of 150 mm × 150 mm and a height of 100 mm was prepared with the resin film on the outside. A 60 W bulb was installed as the light source 2 in the housing 3 and was energized to emit light and generate heat, and the temperature of the surface of the housing 3 when the temperature inside the housing 3 reached a steady state was measured. The evaluation criteria for heat dissipation are as follows.
○: Steady-state temperature is 30 ° C. or less Δ: Steady-state temperature exceeds 30 ° C., 35 ° C. or less X: Steady-state temperature exceeds 35 ° C.

  In Examples 1 to 8, bending workability, conductivity, and heat dissipation were all acceptable. In each evaluation, ○, ○ △, and Δ were accepted, and x was rejected.

On the other hand, in the comparative example 1, since the resin film thickness was too thin, heat dissipation was disqualified.
In Comparative Example 2, the resin film thickness was too thick and the conductivity was not acceptable.
In Comparative Example 3, since the average particle size of the carbon black was too small, the heat dissipation was not acceptable.
In Comparative Example 4, since the average particle size of the carbon black was too large, the bending workability was not acceptable.
In Comparative Example 5, since the specific surface area of the carbon black was too small and the area occupation ratio exceeded 90%, the bending workability was not acceptable.
In Comparative Example 6, since the specific surface area of carbon black was too large and the area occupation ratio was less than 40%, the bending workability was unacceptable.
In Comparative Example 7, the maximum reachable temperature was too low, the baking time was too short, and the area occupancy was less than 40%.
In Comparative Example 8, since the maximum temperature reached was too high and the baking time was too long and the area occupancy was less than 40%, the bending workability was not acceptable.

Next, the second invention according to the present invention will be described in detail based on examples and comparative examples.
(Examples 9 to 19 and Comparative Examples 9 to 12)
25 parts by weight of carbon black shown in Table 2 (based on 100 parts by weight of a thermosetting resin described later) and 5 parts by weight of a dispersant (nonionic compound) (based on 100 parts by weight of a thermosetting resin described later) were mixed with an organic solvent (toluene). And a cyclohexanone mixed solvent), and the mixture was stirred for 85 minutes with a stirring type dispersion apparatus equipped with a propeller blade. Next, thermosetting in which a melamine resin (methylated melamine resin) is blended with a polyester resin having a benzene ring derived from benzene-1,2-dicarboxylic acid and having a molecular weight shown in Table 2 in this dispersion solution. 100 parts by weight of a conductive resin and 12 parts by weight of methyl laurate as a liquid wax were blended, and the mixture was stirred for 80 minutes with a stirring type dispersing device equipped with a propeller blade. Here, it mix | blended with the weight ratio of polyester-type tree: melamine-type resin = 100: 30. The dispersion particle size of the obtained dispersion solution was 8 μm. To this dispersion solution, 30 parts by weight of nickel (scale-like) was further added with respect to 100 parts by weight of the thermosetting resin, and the mixture was stirred for 75 minutes with a stirrer equipped with a toothed disk blade to prepare a paint. The amount of the organic solvent was 1 liter with respect to 137 g of the total amount of the thermosetting resin, carbon black and liquid wax. Regarding the liquid wax, methyl myristate was used instead of methyl laurate in Example 17, isopropyl myristate was used instead of methyl laurate in Example 18, and 100 weight of thermosetting resin was used in Example 19. 5 parts by weight of methyl laurate was blended with respect to parts.

As the aluminum material, an aluminum plate (material: JIS A5052) having a thickness of 0.6 mm was used. The both surfaces were degreased with a commercially available aluminum degreasing agent and washed with water. Next, chemical conversion treatment was performed on both surfaces of the aluminum plate with a commercially available phosphoric acid chromate treatment solution. Then, it applied to one surface of the aluminum plate which carried out the chemical conversion treatment of the said coating material by the roll coat system, and baked with the hot air oven, and produced the resin coating aluminum material. The baking conditions were a maximum temperature of 230 ° C. and a baking time of 50 seconds. Only in Example 16, the maximum reached plate temperature was 240 ° C., and the baking time was 60 seconds. The average particle diameter of carbon black and nickel and the specific surface area of carbon black were measured in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 8. Further, as a result of the fluorescent X-ray analysis of the coating amount of the chemical conversion coating, the chromium amount was 30 mg / m ² as in Example 1.

(Example 20)
30 parts by weight of carbon black shown in Table 2 (based on 100 parts by weight of a thermosetting resin described later) and 5 parts by weight of a dispersant (nonionic compound) (based on 100 parts by weight of a thermosetting resin described later) were mixed with an organic solvent (toluene). And a cyclohexanone mixed solvent), and the mixture was stirred for 40 minutes with a stirring type dispersion apparatus equipped with a propeller blade. Next, thermosetting in which a melamine resin (methylated melamine resin) is blended with a polyester resin having a benzene ring derived from benzene-1,2-dicarboxylic acid and having a molecular weight shown in Table 2 in this dispersion solution. 100 parts by weight of the conductive resin and 12 parts by weight of methyl laurate as a liquid wax were mixed, and the mixture was stirred for 45 minutes with a stirring type dispersion apparatus equipped with a propeller blade. Here, it mix | blended with the weight ratio of polyester-type tree: melamine-type resin = 100: 30. The dispersion particle size of the obtained dispersion solution was 9 μm. To this dispersion solution, 80 parts by weight of nickel (scale-like) was further added with respect to 100 parts by weight of the thermosetting resin, and stirred for 50 minutes with a stirrer equipped with a toothed disk blade to prepare a coating material. The amount of the organic solvent was 1 liter with respect to 137 g of the total amount of the thermosetting resin, carbon black and liquid wax.

As the aluminum material, an aluminum plate (material: JIS A5052) having a thickness of 0.6 mm was used. The both surfaces were degreased with a commercially available aluminum degreasing agent and washed with water. Next, chemical conversion treatment was performed on both surfaces of the aluminum plate with a commercially available phosphoric acid chromate treatment solution. Then, it applied to one surface of the aluminum plate which carried out the chemical conversion treatment of the said coating material by the roll coat system, and baked with the hot air oven, and produced the resin coating aluminum material. As for the baking conditions, the maximum reached plate temperature was 200 ° C., and the baking time was 70 seconds. The average particle diameter of carbon black and nickel and the specific surface area of carbon black were measured in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 8. Further, as a result of the fluorescent X-ray analysis of the coating amount of the chemical conversion coating, the chromium amount was 30 mg / m ² as in Example 1.

(Example 21)
20 parts by weight of carbon black shown in Table 2 (based on 100 parts by weight of a thermosetting resin described later) and 5 parts by weight of a dispersant (nonionic compound) (based on 100 parts by weight of a thermosetting resin described later) were mixed with an organic solvent (toluene). And a cyclohexanone mixed solvent), and the mixture was stirred for 160 minutes with a stirring type dispersion apparatus equipped with a propeller blade. Next, thermosetting in which a melamine resin (methylated melamine resin) is blended with a polyester resin having a benzene ring derived from benzene-1,2-dicarboxylic acid and having a molecular weight shown in Table 2 in this dispersion solution. 100 parts by weight of the conductive resin and 12 parts by weight of methyl laurate as a liquid wax were mixed, and the mixture was stirred for 155 minutes with a stirring type dispersion apparatus equipped with a propeller blade. Here, it mix | blended with the weight ratio of polyester-type tree: melamine-type resin = 100: 30. The dispersion particle size of the obtained dispersion solution was 5 μm. To this dispersion solution, 40 parts by weight of nickel (scale-like) was further added with respect to 100 parts by weight of the thermosetting resin, and stirred for 150 minutes with a stirrer equipped with a toothed disk blade to prepare a paint. The amount of the organic solvent was 1 liter with respect to 137 g of the total amount of the thermosetting resin, carbon black and liquid wax.

As the aluminum material, an aluminum plate (material: JIS A5052) having a thickness of 0.6 mm was used. The both surfaces were degreased with a commercially available aluminum degreasing agent and washed with water. Next, chemical conversion treatment was performed on both surfaces of the aluminum plate with a commercially available phosphoric acid chromate treatment solution. Then, it applied to one surface of the aluminum plate which carried out the chemical conversion treatment of the said coating material by the roll coat system, and baked with the hot air oven, and produced the resin coating aluminum material. The baking conditions were a maximum reached plate temperature of 235 ° C. and a baking time of 50 seconds. The average particle diameter of carbon black and nickel and the specific surface area of carbon black were measured in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 8. Further, as a result of the fluorescent X-ray analysis of the coating amount of the chemical conversion coating, the chromium amount was 30 mg / m ² as in Example 1.

(Comparative Example 13)
20 parts by weight of carbon black shown in Table 2 (based on 100 parts by weight of a thermosetting resin described later) and 5 parts by weight of a dispersant (nonionic compound) (based on 100 parts by weight of a thermosetting resin described later) were mixed with an organic solvent (toluene). And a cyclohexanone mixed solvent), and the mixture was stirred for 10 minutes by a stirring type dispersion apparatus equipped with a propeller blade. Next, thermosetting in which a melamine resin (methylated melamine resin) is blended with a polyester resin having a benzene ring derived from benzene-1,2-dicarboxylic acid and having a molecular weight shown in Table 2 in this dispersion solution. 100 parts by weight of a conductive resin and 12 parts by weight of methyl laurate as a liquid wax were blended, and the mixture was stirred for 12 minutes with a stirring type dispersion apparatus equipped with a propeller blade. Here, it mix | blended with the weight ratio of polyester-type tree: melamine-type resin = 100: 30. The dispersion particle size of the obtained dispersion solution was 15 μm. To this dispersion solution, 50 parts by weight of nickel (scale-like) was further added with respect to 100 parts by weight of the thermosetting resin, and stirred for 13 minutes with a stirrer equipped with a toothed disk blade to prepare a coating material. The amount of the organic solvent was 1 liter with respect to 137 g of the total amount of the thermosetting resin, carbon black and liquid wax.

As the aluminum material, an aluminum plate (material: JIS A5052) having a thickness of 0.6 mm was used. The both surfaces were degreased with a commercially available aluminum degreasing agent and washed with water. Next, chemical conversion treatment was performed on both surfaces of the aluminum plate with a commercially available phosphoric acid chromate treatment solution. Then, it applied to one surface of the aluminum plate which carried out the chemical conversion treatment of the said coating material by the roll coat system, and baked with the hot air oven, and produced the resin coating aluminum material. The baking conditions were a maximum reached plate temperature of 170 ° C. and a baking time of 10 seconds. The average particle diameter of carbon black and nickel and the specific surface area of carbon black were measured in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 8. Further, as a result of the fluorescent X-ray analysis of the coating amount of the chemical conversion coating, the chromium amount was 30 mg / m ² as in Example 1.

(Comparative Example 14)
30 parts by weight of carbon black shown in Table 2 (based on 100 parts by weight of a thermosetting resin described later) and 5 parts by weight of a dispersant (nonionic compound) (based on 100 parts by weight of a thermosetting resin described later) were mixed with an organic solvent (toluene). And a cyclohexanone mixed solvent), and the mixture was stirred for 210 minutes with a stirring type dispersion apparatus equipped with a propeller blade. Next, thermosetting in which a melamine resin (methylated melamine resin) is blended with a polyester resin having a benzene ring derived from benzene-1,2-dicarboxylic acid and having a molecular weight shown in Table 2 in this dispersion solution. 100 parts by weight of the conductive resin and 12 parts by weight of polyethylene wax which is a powdery wax instead of the liquid wax were blended, and the mixture was stirred for 215 minutes with a stirring type dispersion apparatus equipped with a propeller blade. Here, it mix | blended with the weight ratio of polyester-type tree: melamine-type resin = 100: 30. The dispersion particle size of the obtained dispersion solution was 4 μm. To this dispersion solution, 50 parts by weight of nickel (scale-like) was further added with respect to 100 parts by weight of the thermosetting resin, and stirred for 220 minutes with a stirrer equipped with a toothed disk blade to prepare a coating material. The amount of the organic solvent was 1 liter with respect to 137 g of the total amount of the thermosetting resin, carbon black and liquid wax.

As the aluminum material, an aluminum plate (material: JIS A5052) having a thickness of 0.6 mm was used. The both surfaces were degreased with a commercially available aluminum degreasing agent and washed with water. Next, chemical conversion treatment was performed on both surfaces of the aluminum plate with a commercially available phosphoric acid chromate treatment solution. Then, it applied to one surface of the aluminum plate which carried out the chemical conversion treatment of the said coating material by the roll coat system, and baked with the hot air oven, and produced the resin coating aluminum material. The baking conditions were a maximum reached plate temperature of 320 ° C. and a baking time of 95 seconds. The average particle diameter of carbon black and nickel and the specific surface area of carbon black were measured in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 8. Further, as a result of the fluorescent X-ray analysis of the coating amount of the chemical conversion coating, the chromium amount was 30 mg / m ² as in Example 1.

(Comparative Example 15)
Carbon black having an average particle size of 120 nm and a specific surface area of 14 m ² / g (based on 100 parts by weight of thermosetting resin described later) and 5 parts by weight of a dispersant (nonionic compound) (described later thermosetting) The resin was added to an organic solvent (mixed solvent of toluene and cyclohexanone) and stirred for 80 minutes with a stirring type dispersion device equipped with a propeller blade. Next, 100 parts by weight of a thermosetting resin in which a melamine resin (methylated melamine resin) is blended with a polyester resin having no benzene ring in the molecule and a molecular weight of 38,000, 12 parts by weight of methyl laurate was blended as a wax, and the mixture was stirred for 85 minutes with a stirring type dispersing device equipped with a propeller blade. Here, it mix | blended with the weight ratio of polyester-type tree: melamine-type resin = 100: 30. The dispersion particle size of the obtained dispersion solution was 7 μm. To this dispersion solution, 45 parts by weight of nickel (scale-like) with respect to 100 parts by weight of the thermosetting resin was further added and stirred for 90 minutes with a stirrer equipped with a toothed disk blade to prepare a coating material. The amount of the organic solvent was 1 liter with respect to 137 g of the total amount of the thermosetting resin, carbon black and liquid wax.

  As the aluminum material, an aluminum plate (material: JIS A5052) having a thickness of 0.6 mm was used. The both surfaces were degreased with a commercially available aluminum degreasing agent and washed with water. Next, chemical conversion treatment was performed on both surfaces of the aluminum plate with a commercially available phosphoric acid chromate treatment solution. Then, it applied to one surface of the aluminum plate which carried out the chemical conversion treatment of the said coating material by the roll-coating system, and baked with the hot air oven, but the coating external appearance was inferior and the uniform resin-coated aluminum material was not able to be produced.

  Table 2 shows the resin film thickness, the average particle diameter of carbon black, the specific surface area, Ra / RSm, and the surface energy of the resin-coated aluminum material samples prepared in Examples 9 to 21 and Comparative Examples 9 to 15. Ra and RSm were measured with a stylus type roughness meter, and Ra / RSm was calculated. The surface energy was calculated by dropping pure water and diiodomethane onto the surface of the resin film and determining the contact angle. Furthermore, bending workability, conductivity, and heat dissipation were evaluated in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 8, and corrosion resistance was further evaluated by the following method. In all the evaluation results, ○, ○ △, and Δ were accepted, and x was rejected. The results are also shown in Table 2.

<Corrosion resistance>
A 180 ° 2T bend was performed with the resin film of the sample outside, a salt spray test 100 h was performed, and the degree of corrosion of the bent portion was visually observed. The evaluation criteria are as follows.
○: Corrosion is not observed ○ △: Slight corrosion is observed △: Corrosion is observed in half of the area ×: Corrosion is observed on the entire surface

  In Examples 9 to 21, bending workability, conductivity, heat dissipation, and corrosion resistance were all acceptable.

In Comparative Example 9, since the resin film thickness was too thin, the corrosion resistance and heat dissipation were inferior.
In Comparative Example 10, the number average molecular weight of the polyester-based resin was too small, so that the corrosion resistance was inferior.
In Comparative Example 11, the heat dissipation was inferior because the average particle size of the carbon black was too small.
In Comparative Example 12, since the average particle size of carbon black was too large, bending workability and corrosion resistance were inferior.
In Comparative Example 13, the resin film thickness was too thick and the average particle size of carbon black was too large. Furthermore, the maximum temperature reached was too low and the baking time was too short. As a result, bending workability, conductivity, and corrosion resistance were inferior.
In Comparative Example 14, the resin film thickness was too thick, the average particle size of carbon black was too large, and polyethylene wax was used instead of liquid wax. Furthermore, the maximum temperature reached was too high and the baking time was too long. As a result, bending workability, conductivity, and corrosion resistance were inferior.
In Comparative Example 15, since a polyester resin having no benzene ring in the molecule and having a number average molecular weight too large was used, a uniform resin-coated aluminum material could not be obtained, and evaluation could not be performed.

  According to the present invention, for example, a heat-dissipating resin-coated aluminum material having excellent conductivity, bending workability, and corrosion resistance, in addition to heat dissipation, used for housings and heat sinks of electronic parts, home appliances and the like that generate heat internally. Can be provided.

DESCRIPTION OF SYMBOLS 1 ... Resin-coated aluminum material 2 ... Light source 3 ... Housing 4 ... Powdered wax 5 ... Liquid wax D1 ... Water diffusion direction in powdered wax D2 ... Liquid Direction of water diffusion near the surface of the wax

Claims (6)

An aluminum material, a chemical film formed on both surfaces of the aluminum material, and a resin film formed on at least one surface of the chemical film and having a thickness of 0.4 to 1.9 μm,
The resin film includes a polyester resin having a benzene ring in the molecule and a number average molecular weight of 21000 to 28000, a melamine resin, carbon black having an average particle diameter of 115 to 140 nm, nickel, A heat-dissipating resin-coated aluminum material formed from a paint containing liquid wax.   The heat-dissipating resin-coated aluminum material according to claim 1, wherein Ra / μm is 0.058 or less, where Ra (μm) is the arithmetic average roughness of the resin film surface, RSm (μm) is the contour curve average length. . The surface energy of the resin film surface is 60 × 10 -3 ^{J /} m ² or less, the heat dissipation resin coated aluminum material according to claim 1 or 2.   In the paint, the proportion of melamine resin is 5 to 60 parts by weight, carbon black is 15 to 35 parts by weight, and nickel is 30 to 100 parts by weight with respect to 100 parts by weight of the polyester resin. The heat-dissipating resin-coated aluminum material according to any one of claims 1 to 3, wherein the liquid wax is blended at a ratio of 1 to 15 parts by weight.   The heat-dissipating resin-coated aluminum material according to any one of claims 1 to 4, wherein an area occupation ratio of carbon black on the surface of the resin film is 50 to 70%. In the manufacturing method of the heat radiation resin covering aluminum material according to any one of claims 1 to 5,
A process of chemical conversion treatment on both sides of the aluminum material;
Carbon black having an average particle diameter of 115 to 140 nm and a dispersing agent are added to an organic solvent, and these additives are dispersed therein. The additive has a benzene ring in the molecule and has a number average molecular weight of 21000 to 28000. A step of preparing a paint by further adding and dispersing nickel to a dispersed particle size of 10 μm or less by adding and dispersing a polyester-based resin, a melamine-based resin, and a liquid wax;
Applying the paint to at least one surface of the aluminum material subjected to the chemical conversion treatment;
A step of forming a resin film having a thickness of 0.4 to 1.9 μm by baking and curing the applied paint under conditions where the maximum plate temperature is 200 to 250 ° C. and the baking time is 20 to 80 seconds. A method for producing a heat-dissipating resin-coated aluminum material.

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