JP2011156825A - Aluminum resin-coated material, manufacturing method thereof and hybrid material laminate made up of aluminum resin-coated material and steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid material laminate which shows excellent bonding strength and galvanic corrosion by making a mechanical clinching of an aluminum resin-coated material having excellent strength, moldability and corrosion resistance, with a steel. <P>SOLUTION: The aluminum resin-coated material is composed of an aluminum material and a coat with a dry thickness of 0.5 to 10 μm formed on the surface of the aluminum material. The coat contains: an aqueous urethane resin; 1 to 10 pts.wt. of silica having an average particle diameter of 0.01 to 0.05 μm based on 100 pts.wt. of the solid content of the aqueous urethane resin; and 1 to 30 pts.wt. of a lubricant having an average particle diameter of 0.1 to 0.5 μm based on 100 pts.wt. of the solid content of the water urethane resin. In addition, the concentration of silica which is present in the coating film of up to 0.1 μm inclusive in the thickness direction from the interface of the coat with the aluminum material, is higher than the concentration of the silica which is present on the surface side of the coat. Also, the hybrid material laminate consisting of the aluminum resin-coated material and the steel and the methods for manufacturing the aluminum resin-coated material and the hybrid material laminate are provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an aluminum resin coating material used for a dissimilar material laminate of dissimilar metal members of an aluminum material and a steel material in the transportation field of automobiles, railway vehicles, etc., machine parts, building structures, etc., and the dissimilar material laminate, and these It relates to the manufacturing method.

  Aluminum materials and aluminum alloy materials (hereinafter collectively referred to as “aluminum materials”) have good corrosion resistance and are lightweight, so that beverage can materials, building materials, home appliance materials including electric and electronic parts, and automobile materials It is widely applied to such uses. In particular, in the field of automobile materials, in order to reduce the weight of the vehicle body, vehicle members such as an aluminum roof panel formed of an aluminum material or an aluminum alloy material are used. When joining a vehicle member made of aluminum, which is a dissimilar metal, and a steel vehicle member, joining by a welding method using conventional equipment such as a resistance spot welder generates a brittle intermetallic compound at the joint interface, There was a problem that the joint strength was low and the reliability was lacking.

  Therefore, in order to ensure the bonding strength between different metal members by bonding by fusion welding, a technique for bonding different metal members via a transition piece has been developed. However, since the transition piece is expensive, implementation is difficult in terms of cost. A method of mechanically joining dissimilar metal members using a self-piercing rivet (SPR) has also been put into practical use. However, this also has a problem in terms of cost because the rivet is expensive.

  Therefore, a technique for mechanically joining dissimilar metal members by mechanical clinch joining by plastic deformation of an aluminum alloy material has attracted attention. Mechanical clinch joining has the advantages of low cost, dissimilar metal joining, short joining time, and no contact part due to melting of dissimilar metals, so that members can be easily replaced. FIG. 4 shows a schematic diagram of a cross section in which an aluminum material and a steel material are TOX joined, and FIG. 5 shows a schematic diagram of a cross section in which the aluminum material and a steel material are TOG-L-LOC joined. In both figures, 1 indicates an aluminum material, 2 indicates a steel material, and 6 indicates a joint surface.

  However, when dissimilar metals are joined together in this way, electrolytic corrosion is caused by an electrolyte such as rainwater that has entered a minute gap at the contact point between the two metals. This electric corrosion not only deteriorates the appearance of the car body but also causes the intrusion of rainwater into the passenger compartment. For this reason, there has been used means for joining both materials with an electrical insulating sealing agent that has excellent weather resistance and prevents the occurrence of electrolytic corrosion so that different metals do not directly contact in an electrolytic corrosion environment.

  Patent Document 1 describes that a plated steel plate frequently used as an automobile material is mechanically caulked and joined. In this caulking joining, there is a problem that galling is likely to occur in a punch as a processing jig, the die life is short, and it is difficult to form an interlock in which an aluminum material is caulked on a high-strength steel plate. Also, when the panel rigidity is small, as in the case of joining an aluminum roof to a steel vehicle body, the panel (vehicle use) is caused by the difference in thermal expansion coefficient and the curing shrinkage of the sealant between two different metal parts for vehicles. Member) There was also a problem that local distortion occurred on the outer surface.

  Therefore, an attempt has been made to mechanically join an insulating film or tape between different kinds of metal members without going through a thermosetting process, but when the joining portion changes two-dimensionally or three-dimensionally. However, there was a problem that a film or a tape could not follow the shape of the joint surface. Furthermore, even if the joining portion has a primary shape, the work of attaching a film or tape to the joining portion is complicated and there is a problem that the working efficiency is lowered.

  Patent Document 2 describes a joining structure of dissimilar metals having a coating film adhesion with an aluminum material or a non-adhesive insulating seal layer. Aluminum materials and steel materials are different in physical properties such as melting point and linear expansion coefficient, so metallurgical joining (melt joining such as spot welding) is not adopted, and mechanical joining is adopted. However, in the dissimilar metal joining by the mechanical joining, there is a problem that it is difficult to form a joint part having a complicated shape such as caulking and interlocking.

JP 2001-099113 A Japanese Patent Laid-Open No. 2002-284045

  An object of this invention is to provide the aluminum resin coating material which has the outstanding moldability and corrosion resistance. It is another object of the present invention to provide a dissimilar material laminate in which contact corrosion due to dissimilar metals is suppressed and the bonding strength and bondability are excellent by mechanical clinch joining of the aluminum resin coating material and the steel material.

  When the present inventors join a steel material with an aluminum material on which a coating film containing resin, silica, and lubricant as essential constituents is joined to form a laminated body, the thickness from the interface with the aluminum material When the concentration of silica existing up to 0.1 μm in the direction is higher than the concentration of silica existing on the surface side, the corrosion resistance of the coating film between the aluminum material and the steel material improves both electrical insulation properties And it discovered that the contact corrosion of a dissimilar material laminated body was suppressed. It has been found that excellent bonding strength can be obtained by suppressing such contact corrosion. Furthermore, since the silica concentration was low on the coating film surface side, it was also found that the lubricity of the coating film was not impaired, and as a result, excellent bondability with the steel material was obtained.

  The present invention includes, in claim 1, an aluminum material made of aluminum or an aluminum alloy, and a coating film formed on at least one surface of the aluminum material and having a dry thickness of 0.5 to 10 μm. An aqueous urethane resin having an average particle diameter of 0.01 to 0.05 μm, 1 to 10 parts by weight of silica with respect to 100 parts by weight of the solid content of the aqueous urethane resin, and 0.1 to 0.5 μm In a coating film having an average particle size of 1 to 30 parts by weight of a lubricant with respect to 100 parts by weight of the solid content of the water-based urethane resin, up to 0.1 μm in the thickness direction from the interface with the aluminum material The aluminum resin coating material is characterized in that the concentration of silica present in is higher than the concentration of silica present on the surface side.

  According to the present invention, in claim 2, the concentration of the lubricant present in the coating film having a depth of 0.1 μm in the depth direction from the coating film surface is set higher than the concentration of the lubricant present in the coating film deeper than that. did. In claim 3, the silica contained in the coating film is calcium ion exchanged silica.

  According to a fourth aspect of the present invention, the aluminum resin coating material according to claim 1 and the steel material are stacked so that the coating film of the aluminum resin coating material is in contact with the steel material, and the punch side is an aluminum resin coating material. The side was arranged as a steel material, and the aluminum resin coating material and the steel material were joined by mechanical clinching to obtain a dissimilar material laminate.

  Further, according to the present invention, in claim 5, the aluminum resin coating material according to claim 3 and the steel material are stacked so that the coating film of the aluminum resin coating material is in contact with the steel material, and the punch side is an aluminum resin coating material. The side was arranged as a steel material, and the aluminum resin coating material and the steel material were joined by mechanical clinching to obtain a dissimilar material laminate.

  The present invention according to claim 6 has an aqueous urethane resin and an average particle diameter of 0.01 to 0.05 μm on at least one surface of an aluminum material made of aluminum or an aluminum alloy, and has a solid content of 100 of the aqueous urethane resin. 1 to 10 parts by weight of silica with respect to parts by weight, 1 to 30 parts by weight of lubricant having an average particle size of 0.1 to 0.5 μm and 100 parts by weight of the solid content of the aqueous urethane resin; An aluminum resin coating material characterized in that a coating film having a thickness of 0.5 to 10 μm is formed by a drying process including a heating and holding process in which a water-based paint is applied and held at 60 to 80 ° C. for 5 to 20 seconds. It was set as the manufacturing method. In claim 7, the silica contained in the coating film is calcium ion exchanged silica.

  By this invention, the aluminum resin coating material excellent in a moldability and corrosion resistance is provided. This dissimilar laminate with mechanically clinch-bonded aluminum resin coating material and steel can suppress the contact corrosion of dissimilar metals due to the insulating effect of the coating film, resulting in excellent bonding strength and even better bonding properties Is granted.

It is a graph which shows the GDS measurement result of the element in the aluminum resin coating material which concerns on this invention. It is a schematic diagram showing distribution of the polyethylene wax in the aluminum resin coating material which concerns on this invention. It is explanatory drawing which shows the manufacturing method of the dissimilar-material laminated body which concerns on this invention. It is the schematic diagram of the cross section which carried out TOX joining of the aluminum material and steel. It is a schematic diagram of the cross section which carried out TOG-L-LOC joining of the aluminum material and steel.

Hereinafter, the present invention will be described in detail for each element.
(1) Aluminum resin coating material The aluminum resin coating material according to the present invention has an aqueous urethane resin, silica, and a lubricant as essential constituent elements on at least one surface of an aluminum material made of aluminum or an aluminum alloy. A coating having a dry thickness of 10 μm is provided.

A. Aluminum material As the aluminum material used in the present invention, a pure aluminum material and an aluminum alloy material containing one or more of iron, copper, manganese, silicon, magnesium, zinc, chromium, nickel and the like can be used. . Although the thickness of an aluminum material is not specifically limited, A 0.1-3 mm thing is used suitably.

  In applying the present invention, since the oil adhering to the surface of the aluminum material in the manufacturing process may adversely affect the formation of the coating film, degreasing treatment with an alkaline aqueous solution and / or an acidic aqueous solution is performed for the purpose of removing them. It is preferable to carry out. Further, when the oxide film present on the surface of the aluminum material is thick, the bonding strength with other members is impaired due to the cohesive failure of the oxide film. As a method for removing the oxide film, a cleaning treatment using an alkaline aqueous solution and / or an acidic aqueous solution may be mentioned. Sodium hydroxide, potassium hydroxide, or the like is used as the alkaline aqueous solution used for the degreasing treatment or cleaning treatment, and sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid, a mixed solution of nitric acid and hydrofluoric acid, or the like is used as the acidic aqueous solution. In these degreasing treatments and cleaning treatments, a method performed as a normal aluminum treatment method is used, and a commercially available treatment solution may be used.

B. Coating Film The coating film according to the present invention is obtained by applying an aqueous urethane resin, silica and a lubricant as essential components, and applying and drying an aqueous coating containing these on an aluminum substrate. The coating thickness is 0.5 to 10 μm in the dry state. If the thickness is less than 0.5 μm, the coating film is too thin and galling occurs during molding, so that the moldability cannot be satisfied. On the other hand, when the thickness exceeds 10 μm, peeling powder is generated from the dried coating film, which not only lacks moldability but also lacks strength and corrosion resistance. In addition, the maintenance frequency of the mold is increased and the working environment is deteriorated.

B-1. Aqueous Urethane Resin The aqueous urethane resin used in the present invention refers to a water-soluble polymer urethane and an aqueous emulsion resin of urethane resin.

  The urethane resin can be obtained by polymerizing a polyfunctional isocyanate, a polyhydric alcohol, a bifunctional active hydrogen-containing compound having an acidic group and the like by a conventionally known method. The polyvalent isocyanate is not particularly limited. For example, ethylene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane-1,4-diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, p-xylylene diisocyanate, 1 , 4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, 1,5-naphthylene diisocyanate, etc. Can be mentioned. Furthermore, mixtures of these can be used.

  The polyhydric alcohol is not particularly limited, and those conventionally known as polyurethane emulsion synthesis raw materials can be used. For example, ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, neo Examples include pentyl glycol, cyclohexanedimethanol, glycerol, trimethylolpropane, pentaerythritol, polyester polyol, polyester polyamide polyol, polyether polyol, polythioether polyol, polycarbonate polyol, polyacetal polyol, polyolefin polyol, polysiloxane polyol, and the like. .

  The bifunctional active hydrogen-containing compound having an acidic group is not particularly limited, and those conventionally known as synthetic raw materials for anionic polyurethane emulsions can be used. For example, 2.2-dimethylolpropanoic acid can be used. 2.2-dimethylolbutanoic acid, lysine cystine, 3,5-diaminobenzoic acid and the like.

  The method for synthesizing the aqueous resin used in the present invention is not particularly limited, and those synthesized by industrially used methods can be used. The aqueous urethane resin according to the present invention can be used after neutralizing with sodium hydroxide, potassium hydroxide or the like.

  In addition to the urethane resin, an acrylic resin, a polyester resin, a polyvinyl alcohol resin, or the like may be added as long as the performance is not deteriorated. The aqueous urethane resin is dissolved or dispersed in water using a homogenizer, a mixer or the like to form an aqueous paint.

B-2. Silica In the present invention, silica is added to the coating film for the purpose of improving the strength, moldability and corrosion resistance of the coating film. In the present invention, the silica contained in the coating film is 1 to 10 parts by weight, preferably 3 to 7 parts by weight, based on 100 parts by weight of the solid content of the aqueous urethane resin. The average particle diameter of silica is 0.01 to 0.05 μm, preferably 0.01 to 0.03 μm. If the amount of silica is less than 1 part by weight, sufficient strength and corrosion resistance cannot be obtained. On the other hand, if it exceeds 10 parts by weight, the coating film becomes brittle, and sufficient strength and corrosion resistance cannot be obtained. In addition, since galling is likely to occur during molding, the moldability is also poor. If the average particle size is less than 0.01 μm, sufficient strength and corrosion resistance cannot be obtained, and if it exceeds 0.05 μm, the coating film becomes brittle, and sufficient strength and corrosion resistance cannot be obtained. In addition, since galling is likely to occur during molding, the moldability is also poor.

  As the silica, colloidal silica or fumed silica can be used. Examples of colloidal silica include Snowtex O, Snowtex OS, Snowtex OXS, Snowtex OUP, Snowtex AK, Snowtex O40, Snowtex OL, Snowtex OL40, Snowtex OZL manufactured by Nissan Chemical Industries, Ltd. , Snowtex XS, Snowtex S, Snowtex NXS, Snowtex NS, Snowtex N, Snowtex QAS-25, Snowtex LSS-35, Snowtex LSS-45, Snowtex LSS-75, Catalyst Kasei Kogyo Co., Ltd. ) Cataloid S, Cataloid SI-350, Cataloid SI-40, Cataloid SA, Cataloid SN, Adelite AT-20-50, Adelite AT-20N, Adelite AT-300, manufactured by Asahi Denka Kogyo Co., Ltd. Delight AT-300S, can be used ADELITE AT20Q like.

In the present invention, in addition to the above, ion-exchange colloidal silica in which the surface of the colloidal silica is substituted with cations such as calcium, zinc, cobalt, lead, strontium, lithium, barium, and manganese can be used. Ion exchange colloidal silica, which exchanges silicon ions in colloidal silica, releases metal ions such as substituted calcium from the silica surface in a corrosive environment, and the released metal ions protect the aluminum material surface to prevent rust. It is thought that appears. In the present invention, it is preferable to use such ion exchange colloidal silica, particularly calcium ion exchange colloidal silica, from the viewpoint of corrosion resistance. The calcium content of the calcium ion exchange colloidal silica is preferably in the range of 2 to 15%. Examples of calcium ion exchange colloidal silica include SHIELDEX (W.
R. Grace & Co. , Fuji Syria Chemical, etc.).

  A characteristic of the coating film is that there is a distribution in the silica concentration in the coating film. In FIG. 1, the GDS measurement result of each element in an aluminum resin coating material is shown. Corresponding to the sputtering time of 2.6 s is the surface where the substrate of the aluminum material 1 is exposed, that is, the interface I between the aluminum material 1 and the coating film 3. In the figure, the right side from the interface I is the aluminum material 1, and the left side is the coating film 3. The surface of the coating film 3 corresponds to the sputtering time of 0 s. The concentration of silica existing from the interface I to 0.1 μm on the coating film side (L in the figure) is higher than the concentration of silica existing on the coating film surface side. When silica is unevenly distributed on the surface of the coating film, good moldability with little galling can be obtained without impairing lubricity. Further, in a portion where a large amount of a predetermined portion of silica exists from the interface I with the aluminum material 1, a dense structure is formed, and the coating strength and corrosion resistance are increased.

B-3. Lubricant The lubricant added to the lubricating film in the present invention has an average particle size of 0.1 to 0.5 μm. As such a lubricant, it is preferable to use at least one of a polyolefin wax and a fluororesin. Examples of the polyolefin wax include polyethylene wax, polypropylene wax, modified polyethylene, and the like, or a mixture thereof. Examples of the fluororesin include polytetrafluoroethylene (PTFE), polyhexafluoropolyprene, polyvinylidene fluoride, and the like, or a mixture thereof. As the polyolefin wax and fluororesin, those that are stably dispersed in water are used. In addition, lubricating substances that are incompatible with aqueous urethane resins, such as microcrystalline, lanolin, carnauba, fatty acids, fatty acid esters, and aliphatic alcohols, are added to polyolefin-based waxes and fluororesins within a range that does not degrade the performance of the coating film. May be used.

  When the average particle size of the lubricant is less than 0.1 μm, the friction coefficient cannot be sufficiently reduced, and the formability of the coating film cannot be satisfied. On the other hand, when the average particle size exceeds 0.5 μm, the detachment from the lubricating film increases, resulting in poor coating strength, corrosion resistance and moldability. The addition amount of the lubricant is 1 to 30 parts by weight with respect to 100 parts by weight of the solid content of the aqueous urethane resin. If it is less than 1 part by weight, sufficient moldability cannot be obtained, and if it exceeds 30 parts by weight, the strength of the coating film is reduced, and the moldability and corrosion resistance due to the desorption of the lubricant are also lacking.

  In the coating film used in the present invention, it is preferable that a distribution exists in the lubricant concentration in the coating film. A schematic representation of the lubricant concentration in the coating film by SEM photograph is shown in FIG. As shown in FIG. 2, the concentration of the lubricant 7 existing in the coating film 3 from the surface 31 of the coating film 3 to 0.1 μm in the depth direction (M in the figure) is increased in the coating film deeper than that. The concentration is higher than the concentration of the existing lubricant 7. The presence of a large amount of lubricant 7 on the coating film surface 31 side improves the lubrication performance of the coating film. As a result, better moldability with less galling can be obtained.

  The coating film used in the present invention is formed using an aqueous paint in which the water-based urethane resin, silica, and lubricant are dissolved or dispersed in a solvent. Although a density | concentration is selected suitably, 60-70g is preferable with respect to 1 liter of solvent about water-based urethane resin. Water-based paints include metal oxides, conductive additives, surfactants, thickeners, antifoaming agents, leveling agents, dispersants, drying agents, stabilizers, antiskinning agents, antifungal agents, preservatives, An antifreezing agent or the like can be added according to the purpose within a range not deteriorating the coating film performance. The solvent of the paint is mainly water, but for the purpose of improving the paintability, alcohol, ketone, cellosolve-based aqueous organic solvent may be added as necessary so long as the coating film performance is not impaired.

C. Next, a method for producing the aluminum resin coating material of the present invention will be described.
The aluminum resin coating material of the present invention is a heating method in which an aqueous paint containing a water-based urethane resin, silica, and lubricant in a predetermined composition is applied to an aluminum material, and then held at a reaching plate temperature of 60 to 80 ° C. for 5 to 20 seconds. It can produce by forming a coating film by making it dry in the drying process including a holding process. As a method for applying the water-based paint, a roll coating method, a roll squeeze method, an air knife method, a chemicoater method, a dipping method, a spray method, a bar coating method, or the like can be used. It is preferable to apply a roll coater method which is excellent in the uniformity of the coating film and has good productivity.

  In the heating and holding process of holding at a reaching plate temperature of 60 to 80 ° C. for 5 to 20 seconds, aluminum ions are dissolved from the aluminum material into the paint on the aluminum material, and gelation of silica is promoted by the aluminum ions. At this time, a water-based urethane resin is also taken into the gelled silica together with aluminum ions to form a dense coating film structure. And, by completely drying the coating film while maintaining this dense structure, a coating film having excellent adhesion with an aluminum material, high moldability with little galling, and excellent corrosion resistance can be obtained. can get.

  As the solvent evaporates, the viscosity of the paint increases, convection of the solvent is suppressed, and the desired distribution state of silica is easily maintained. Since the specific gravity of silica is greater than that of the resin coating film, it is held at a reaching plate temperature of 60 to 80 ° C. for 5 to 20 seconds, so that the resin settles near the aluminum material interface before solidifying by drying, and much in this part. It will be unevenly distributed. Thereby, since the presence of silica can be reduced on the surface side of the coating film, good moldability in which galling is suppressed can be obtained without impairing lubricity. On the other hand, in the region from the interface with the deeper aluminum material of the coating film to 0.1 μm, a dense structure rich in silica is formed, and excellent adhesion with the aluminum material, sufficient strength, Excellent corrosion resistance that does not allow moisture to penetrate is imparted to the coating film. In the coating film formed in this way, the concentration of silica existing from the aluminum material interface to 0.1 μm is higher than the concentration of silica existing on the surface side.

  It is preferable that a large amount of the lubricant having a small surface energy and not compatible with the water-based paint is unevenly distributed on the surface side in such a manner that the lubricant is extruded to the surface side of the coating film as the silica gels. Thereby, the lubricity can be further improved. Similarly to silica, evaporation of the solvent increases the viscosity of the paint, suppresses convection of the solvent, and makes it easier to maintain the desired distribution of the lubricant. Thus, it is preferable to make the concentration of the lubricant present in the coating film from the surface of the coating film to the depth of 0.1 μm in the depth direction higher than the concentration of the lubricant present in the coating film deeper than that. .

  In the heating and holding process of the drying step, if the ultimate plate temperature is less than 60 ° C., the solvent evaporates before the elution of aluminum ions necessary for the uneven distribution of silica occurs, the viscosity of the paint increases, and the uneven distribution of silica occurs. The structure of the coating film is fixed while it is insufficient. As a result, the silica concentration on the coating film surface cannot be reduced, the lubricity is impaired, and the moldability is inferior. When the ultimate plate temperature exceeds 80 ° C., the solvent is evaporated too early, and the distribution is fixed before the uneven distribution of silica sufficiently proceeds. As a result, a reduction in the silica concentration on the coating film surface cannot be achieved, and the lubricity is impaired and sufficient moldability cannot be obtained. Further, when the ultimate plate temperature exceeds 80 ° C., the distribution is fixed before the uneven distribution of the lubricant sufficiently proceeds. As a result, a state where a large amount of lubricant is present on the coating film surface cannot be achieved, which is not preferable from the viewpoint of improving lubricity.

  If the holding time is less than 5 seconds in the heating and holding process, the viscosity of the paint increases due to the solvent evaporating before the elution of aluminum ions necessary for the uneven distribution of silica occurs, and the uneven distribution of silica remains insufficient. The structure of the coating film is fixed. As a result, the silica concentration on the coating film surface cannot be reduced, the lubricity is impaired, and the moldability is inferior. When the heating and holding time exceeds 20 seconds, the distribution in the coating film does not change even if the holding time is longer than this. Therefore, the upper limit is set to 20 seconds from the viewpoint of productivity.

  After the heating and holding process in the drying process, it is preferable to provide a drying process in which the ultimate plate temperature is 100 ° C. or higher and is 1 second or longer. When the ultimate plate temperature is less than 100 ° C. and the drying time is less than 1 second, drying may be insufficient. As a result, corrosion may progress due to moisture in the coating film, resulting in poor corrosion resistance. The upper limit of the ultimate plate temperature is not particularly defined, but it is preferably 250 ° C. or lower because the desired coating film performance cannot be obtained at a high temperature at which the components constituting the coating film are altered. When the drying time exceeds 5 minutes, there is no particular change even after drying for a longer time, and the upper limit is preferably 5 minutes from the viewpoint of productivity. In the heating and holding process and the drying process, a hot air drying furnace, an induction heating furnace, an infrared furnace, or the like can be used.

(Steel)
As the steel material used in the present invention, a steel material containing one or more of iron and carbon, silicon, manganese, phosphorus, sulfur and the like can be used. Although the thickness of steel materials is not specifically limited, A thing of 0.6-1 mm is used suitably. In applying this invention, you may use in the state in which the antirust oil was apply | coated in order to prevent the oil component adhering to the surface of steel materials in the manufacturing process, or the rusting of steel materials. Further, a plated steel sheet provided with various plating layers such as zinc plating, alloyed hot dip galvanizing, and aluminum plating may be used.

(Dissimilar laminate)
The dissimilar material laminate according to the present invention is obtained by stacking the above-described aluminum resin coating material and steel material so that the coating film of the aluminum resin coating material is in contact with the steel material, and joining them by mechanical clinch.

D. Mechanical clinch joining The mechanical clinch joining used in the present invention is a method of mechanically joining dissimilar metal members made of an aluminum material and a steel material by clinching by plastic deformation of an aluminum alloy material. There are no material restrictions and it is a simple joining method, and spot clinching joining, TOX joining, TOG-L-LOC joining, etc. are used. In this joining method, a plurality of plate-like materials are stacked, a die is placed on the back, and the punch is locally pushed by a punch to mechanically clinch the upper and lower laminated materials. The energy consumption required for joining is low, and the generation of harmful gases and other environmental pollution are also low. Moreover, since it can be applied not only to various coating materials but also to materials having different materials and thicknesses, it is widely used in fields such as automobiles, home appliances, and building materials.

E. Laminated structure The dissimilar material laminate according to the present invention is produced by mechanical clinch joining of an aluminum resin coating material and a steel material. As shown in FIG. 3, the aluminum resin coating material 1 and the steel material 2 are stacked so that the coating film 3 is in contact with the steel material 2 (FIG. 3- (a)), the aluminum resin coating material 1 is placed on the punch 4 side, and the die 5 Place steel on the side. Next, the punch 4 is pushed in from above, and the aluminum resin coating material 1 and the steel material 2 are deformed between the die 5 (FIG. 3B). Finally, joining is completed by pulling up the punch 4 (FIG. 3- (c)). The presence of the coating film 3 formed in advance on the aluminum resin coating material 1 on the joining surface 6 does not impair the lubricity at the time of joining because there is little silica on the surface. This facilitates caulking formation during mechanical clinching bonding, and increases the bonding strength. Moreover, the contact corrosion (electric corrosion) which generate | occur | produces when a dissimilar metal contacts is suppressed by the electrical insulation based on the corrosion resistance of the coating film which exists in a joint surface. That is, even if the surface portion of the coating follows the caulking shape of the joint, a predetermined portion from the interface between the aluminum material and the coating has a densely formed silica-rich portion. The material is coated so that the electrical insulation between the aluminum material and the steel material is maintained, and galvanic corrosion is suppressed. In addition, by making a lot of lubricants unevenly distributed on the surface of the coating film, it becomes easier for the aluminum material to follow a complicated joint caulking shape.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, a present Example is only an example and does not limit this invention.

Examples 1-34 and Comparative Examples 1-13
As the aluminum material, an A6022 aluminum alloy plate having a thickness of 1.2 mm was used. Before applying the resin coating to the aluminum alloy plate, the following A1 to A3 were washed to obtain test materials.
Adekabon titer-HUX320 (manufactured by ADEKA Corporation) was used as the water-based urethane resin of the water-based paint, and the following were used as the silica. Moreover, polyethylene wax and PTFE were used for the lubricant. Silica and lubricant were added in amounts shown in Tables 1 and 2. The addition amounts shown in Tables 1 and 2 are parts by weight with respect to 100 parts by weight of the solid content of the aqueous urethane resin. Water was used as a solvent for the aqueous paint, and an aqueous paint was prepared by dissolving or dispersing an aqueous urethane resin, silica and a lubricant in water. The amount of water in the coating was appropriately selected so that the coating thicknesses shown in Tables 1 and 2 were obtained.

  The water-based paint thus prepared was applied to both sides of the test material with a bar coater, and a coating film was formed on one side through a drying process consisting of a heating and holding process in a hot air drying furnace and a drying process. A sample of an aluminum resin coated plate was prepared. Tables 1 and 2 show the conditions of the heating and holding process and the drying process in the drying process.

  As the steel plate, a cold-rolled rolled plate (SPCC) having a thickness of 1.0 mm was used. The aluminum alloy resin-coated plate and the steel plate produced as described above were processed into a tensile test specimen shape and a corrosion resistance test specimen shape, respectively. Mechanical clinch was performed by superimposing the aluminum alloy resin-coated plate processed into the shape of a test piece for a tensile test and the steel plate so that the coating film was in contact with the steel plate. A dissimilar material laminate was prepared using TOX bonding (Tox-Rix presso technique) as a mechanical clinch method. Similarly, for the aluminum alloy resin-coated plate and steel plate processed into the corrosion resistance test piece shape, a dissimilar material laminate was produced using TOX bonding.

The method for cleaning the aluminum plate is described below.
A1: 40 ° C immersion in a commercially available alkaline degreasing agent (sodium hydroxide type) for 10 seconds + 40 ° C,
Immerse in 10% nitric acid for 10 seconds A2: Immerse in 40% at 5 ° C, 5% aqueous sodium hydroxide solution A3: Immerse in 10% nitric acid at 40 ° C for 10 seconds

The silica used is shown below.
B1: AEROSIL200 (dry silica, manufactured by Nippon Aerosil Co., Ltd.)
B2: SHIELDEX (calcium ion exchange silica, manufactured by WR Grace)

A sample of the aluminum alloy resin coated plate prepared as described above was measured and evaluated as follows.
1) Coating film stability The coating film stability was evaluated as an index representing the adhesion and strength of an aluminum alloy resin-coated plate. A cellophane tape was affixed to the coating film formed on the aluminum material, and the presence or absence of release powder adhered to the peeled cellophane tape was visually confirmed. Evaluation was made according to the following criteria.
○: No adhesion of release powder ×: Adhesion of release powder ○ was accepted and x was rejected.

2) Distribution of silica component in coating film A sample of an aluminum alloy resin coated plate was cut into 100 mm × 100 mm. As the distribution of silica in the depth direction in the coating film on the sample, the silicon atom distribution was measured using GD-OES. The measurement results were classified according to the following criteria a and b. The GD-OES apparatus used JY5000RF by Horiba, Ltd., and measured with an anode diameter of 4 mm. As measurement conditions, the argon gas atmosphere pressure was 600 Pa, the output was 30 W, the detection wavelength of silicon atoms was 0.288 μm, and the acceleration voltage of the photomultiplier tube for determining the detection sensitivity of silicon atoms was 999 V. After the measurement, the depth of the hole dug by sputtering was divided by the sputtering time to obtain the sputtering rate, and the sputtering time was converted to the coating film depth.
a: The concentration of silicon atoms present in the coating film from the interface with the aluminum material to 0.1 μm is higher than the concentration of silica present on the surface side b: From the interface with the aluminum material to 0.1 μm The concentration of silicon atoms present in the paint film is less than the concentration of silica present on the surface side.

3) Joining strength The aluminum alloy resin-coated plate and the steel plate were cut into 100 mm × 30 mm and lapped at a portion of 40 mm × 30 mm. Using “FKS-1-0701” manufactured by Tox-Rix Pressotechnics Co., Ltd., punch part number “10.200.2298379”, die part number “14.00.2558052”, molding speed 60 strokes / minute Then, TOX bonding was performed on the laminated portion with the aluminum alloy resin coating material on the punch side and the steel side on the die side, a 160 mm × 30 mm dissimilar material laminate test piece was prepared, and the tensile shear strength of the test piece was measured. Evaluation was made according to the following criteria.
○: Tensile shear strength ≧ 1500 N
Δ: 1500 N> tensile shear strength ≧ 1000 N
X: Tensile shear strength <1000 N
○ was accepted and Δ and × were rejected.

4) Corrosion resistance test An aluminum resin coated plate and a steel plate are cut into 150 mm × 60 mm, wrapped 150 mm × 30 mm, and “FKS-1-0701” manufactured by Tox-Rix Pressotechnics Co., Ltd. is used. 200.298379 ", die part number" 14.00.2558052 ", molding speed 60 strokes / min, punch side with aluminum resin coating material, die side with steel material, and TOX joining to the laminated part, 150mm x 90mm dissimilar material A laminate test piece was prepared. Next, after chemical conversion treatment and electrodeposition coating treatment were applied to this, the edge of the test piece was sealed with white paint (manufactured by Nippon Paint), and this test piece was subjected to a cycle corrosion test (0.5%) in accordance with SAE-J2334. 30 cycles of NaCl + 0.1% CaCl ₂ + 0.075% NaHCO _{3 in} a 25 ° C. aqueous solution → 60 ° C., drying at 50% RH or less → 50 ° C., wet at 98% RH or more) The corrosion resistance was evaluated by measuring the maximum corrosion depth of the aluminum material. Evaluation was made according to the following criteria.
A: Less than 0.1 mm B: 0.1 mm or more and less than 0.2 mm X: 0.2 mm or more A and B were accepted and x was rejected.

  Tables 3 and 4 show the results of evaluation of coating film stability and coating film structure (distribution of silica components in the lubricating coating film) for the aluminum alloy resin-coated plate, and bonding strength and corrosion resistance of the dissimilar material laminate. .

  In Examples 1-34, the coating film stability about an aluminum alloy resin coating board was a pass, and the coating-film structure was also favorable. Moreover, the joint strength and corrosion resistance of the dissimilar material laminate were also acceptable.

In Comparative Example 1, since the coating thickness was too thin, caulking due to TOX bonding was difficult to form, and the coating stability of the aluminum alloy resin coated plate was poor. As a result, the bonding strength and corrosion resistance of the dissimilar material laminate were also inferior.
In Comparative Example 2, since the coating film thickness was too thick, the coating film was cracked and the coating film dropped out significantly, and the coating stability of the aluminum alloy resin coated plate was inferior. Thereby, a metal contact part occurred locally and the corrosion resistance of the dissimilar material laminated body was inferior.
In Comparative Example 3, since the silica particle size in the coating film was too large, the coating film dropped out significantly, and the coating film was cracked, and the coating stability of the aluminum alloy resin coated plate was poor. Thereby, the joining strength and corrosion resistance of the dissimilar material laminate were inferior.
In Comparative Example 4, since the silica content in the coating film was too small, the coating film stability of the aluminum alloy resin coated plate was poor. Thereby, the corrosion resistance of the dissimilar material laminate was inferior.
In comparative example 5, since there was too much silica content in a coating film, the coating film became weak and the coating-film stability of the aluminum alloy resin coating board was inferior. As a result, cracks occurred in the coating film at the joint, and the joint strength and corrosion resistance of the dissimilar material laminate were inferior.
In Comparative Example 6, since the particle size of the lubricant was too small, sufficient caulking could not be performed, and the coating stability of the aluminum alloy resin coated plate was poor. Thereby, the joining strength of the dissimilar material laminate was inferior.
In Comparative Example 7, since the lubricant particle size was too large, the coating film dropped out significantly and cracks occurred in the coating film, and the coating stability of the aluminum alloy resin coated plate was inferior. Thereby, the joining strength and corrosion resistance of the dissimilar material laminate were inferior.
In Comparative Example 8, since the amount of lubricant added was too small, sufficient caulking was not possible, and the coating stability of the aluminum alloy resin coated plate was poor. Thereby, the joining strength of the dissimilar material laminate was inferior.
In Comparative Example 9, since the amount of lubricant added was too large, the strength of the coating film was reduced, and the coating film stability of the aluminum alloy resin coated plate was inferior. Thereby, the joining strength of the dissimilar material laminate was also inferior.
In Comparative Example 10, since the temperature in the heating and holding process of the coating film was too low, the silica concentration on the coating film surface was higher than near the interface with the aluminum material. Thereby, the coating-film stability of the aluminum alloy resin coating board was inferior. Then, cracks were generated in the coating film, and the invasion of moisture into the coating film caused dissimilar metal contact corrosion. As a result, the bonding strength and corrosion resistance of the dissimilar material laminate were inferior.
In Comparative Example 11, since the holding time was short, the silica concentration on the coating film surface was higher than that near the interface with the aluminum material. Thereby, the coating-film stability of the aluminum alloy resin coating board was inferior. Then, cracks were generated in the coating film, and the invasion of moisture into the coating film caused dissimilar metal contact corrosion. As a result, the bonding strength and corrosion resistance of the dissimilar material laminate were inferior.
In Comparative Example 12, since the particle size of the silica in the coating film was too small, the coating film stability of the aluminum alloy resin coated plate was inferior. Thereby, the corrosion resistance of the dissimilar material laminate was inferior.
In Comparative Example 13, since the temperature in the heating and holding process of the coating film was too high, the silica concentration on the coating film surface was higher than near the interface with the aluminum material. The coating stability of the aluminum alloy resin coated plate was poor. Then, cracks were generated in the coating film, and the invasion of moisture into the coating film caused dissimilar metal contact corrosion. As a result, the bonding strength and corrosion resistance of the dissimilar material laminate were inferior.

  An aluminum resin coating material having excellent coating film stability, moldability and corrosion resistance can be provided. Furthermore, the aluminum resin coating material and the steel material are mechanically clinched to provide a dissimilar material laminate in which contact corrosion due to dissimilar metals is suppressed and which has excellent bonding strength and bondability.

1 ... Aluminum resin coating material, aluminum material 2 ... Steel material 3 ... Coating film 31 ... Coating film surface 4 ... Punch 5 ... Die 6 ... Joint surface 7 ... Lubricant I ... Coating with aluminum material Interface with the film L …… Part from the interface to the surface of the coating up to 1 μm M …… Part from the surface of the coating to the depth of 1 μm

Claims (7)

  An aluminum material made of aluminum or an aluminum alloy; and a coating film formed on at least one surface of the aluminum material and having a dry thickness of 0.5 to 10 μm. 1 to 10 parts by weight of silica having an average particle diameter of 01 to 0.05 μm and 100 parts by weight of the solid content of the aqueous urethane resin, and the aqueous particle having an average particle diameter of 0.1 to 0.5 μm 1 to 30 parts by weight of a lubricant with respect to 100 parts by weight of the solid content of the urethane resin, and the concentration of silica present in the coating film from the interface with the aluminum material to 0.1 μm in the thickness direction, An aluminum resin coating material characterized by being higher than the concentration of silica present on the surface side.   The concentration of a lubricant present in a coating film having a depth of 0.1 μm from the surface of the coating film to a depth of 0.1 μm is higher than the concentration of a lubricant present in a coating film deeper than that. Aluminum resin coating material.   The aluminum resin coating material according to claim 1 or 2, wherein the silica is calcium ion exchange colloidal silica.   The aluminum resin coating material and the steel material according to claim 1 or 2 are stacked so that the coating film of the aluminum resin coating material is in contact with the steel material, the punch side is disposed as the aluminum resin coating material, and the die side is disposed as the steel material, A dissimilar material laminate in which an aluminum resin coating material and a steel material are joined by mechanical clinch.   The aluminum resin coating material according to claim 3 and a steel material are stacked such that the coating film of the aluminum resin coating material is in contact with the steel material, the punch side is disposed as the aluminum resin coating material, and the die side is disposed as the steel material, and the aluminum resin is disposed. A dissimilar material laminate in which a coating material and a steel material are joined by mechanical clinch.   An aqueous urethane resin and an average particle diameter of 0.01 to 0.05 μm on at least one surface of an aluminum material made of aluminum or an aluminum alloy, and 1 to 10 relative to 100 parts by weight of the solid content of the aqueous urethane resin Applying an aqueous paint containing 1 part by weight of silica and 1 to 30 parts by weight of a lubricant with respect to 100 parts by weight of the solid content of the aqueous urethane resin having an average particle size of 0.1 to 0.5 µm, A method for producing an aluminum resin coating material, comprising forming a coating film having a thickness of 0.5 to 10 µm by a drying step including a heating and holding step of holding at 60 to 80 ° C for 5 to 20 seconds.   The manufacturing method of the aluminum resin coating material of Claim 6 whose said silica is a calcium ion exchange colloidal silica.

Images