JP7322535B2 - Automobile back door and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to an openable back door provided at the rear part of the vehicle body of an automobile and a manufacturing method thereof.

In the present specification and claims, the term "aluminum" is used to mean both pure aluminum and aluminum alloys, unless otherwise specified.

An automobile called a hatchback type is equipped with an openable back door at its rear portion. This type of automobile is required to improve fuel efficiency by reducing the weight of the back door, but it is difficult to reduce the weight of the back door made of metal such as aluminum or iron. On the other hand, the resin back door may lack the rigidity required for the back door.

Patent Document 1 (Japanese Patent Application Laid-Open No. 2015-71375) discloses a back door consisting of an outer panel and an inner panel. In this back door, at least a part of the outer panel and/or the inner panel includes a metal/resin composite structure, and this structure includes a structure portion made of a resin material and a metal body portion made of aluminum or the like. , and a rib portion made of a resin material. The metal body portion is joined to the structural body portion, the rib portion is joined to the structural body portion and/or the metal body portion, and the rib portion increases the rigidity of the back door.

JP 2015-71375 A

When manufacturing a back door by joining an aluminum member and a resin member like the back door of Patent Document 1, both members must be strong in order to satisfy the strength (eg, rigidity) required for the back door. is preferably joined to.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned technical background, and its object is to provide a back door for automobiles which is provided with an aluminum member and a resin member, has a high joint strength between the two members, and is lightweight, and a method of manufacturing the same. It is in.

The present invention provides the following means.

1) An aluminum member in which one or more resin coating layers are laminated on at least a part of the surface of an aluminum base material, and a resin bonded to the surface of the aluminum member on the resin coating layer side of the aluminum base material. and
The resin coating layer is laminated on the surface-treated surface of the aluminum base,
At least one of the resin coating layers is formed from a resin composition containing an in-situ polymerizable phenoxy resin.

2) the resin coating layer has a plurality of layers, at least one layer of which is formed from a resin composition containing a thermosetting resin;
2. The automotive back door according to the preceding item 1, wherein the thermosetting resin is at least one selected from the group consisting of urethane resins, epoxy resins, vinyl ester resins and unsaturated polyester resins.

3) having a functional group adhesion layer between the surface-treated surface of the aluminum substrate and the resin coating layer;
3. The automotive back door according to the preceding item 1 or 2, wherein the functional group-adhering layer has a functional group introduced from at least one selected from the group consisting of silane coupling agents, isocyanate compounds and thiol compounds.

4) The automotive back door according to any one of the preceding items 1 to 3, wherein the surface treatment is at least one selected from the group consisting of blasting, polishing, etching and chemical conversion.

5) The automotive back door according to any one of the preceding items 1 to 4, wherein the coating layer is a primer layer.

6) The automobile according to any one of the preceding items 1 to 5, wherein the aluminum base material is made of an extruded aluminum profile of an A6000 series alloy, and has properties such as a tensile strength of 240 MPa or more and a Young's modulus of 65 GPa or more. for backdoor.

7) The automotive vehicle according to any one of the preceding items 1 to 5, wherein the aluminum base material is made of an aluminum forged material of an A4000 series alloy and has properties such as a tensile strength of 350 MPa or more and a Young's modulus of 70 GPa or more. back door.

8) comprising a resin inner panel arranged inside the vehicle body interior, a resin outer panel arranged outside the vehicle body, and an aluminum frame arranged between the two panels,
The frame is the aluminum member,
Each panel is the resin member,
At least a contact surface of the frame with each panel is a surface on the resin coating layer side,
8. The automotive back door according to any one of the preceding items 1 to 7, wherein each panel is joined to the contact surface of the frame.

9) A method for manufacturing an automobile back door according to any one of the preceding items 1 to 8, comprising:
When molding a resin member by injection molding, transfer molding, press molding, filament winding molding, or hand lay-up molding, the resin member is joined to the resin coating layer side of the aluminum substrate of the aluminum member. A method for manufacturing an automobile back door.

The present invention has the following effects.

In the above item 1, since the back door includes the aluminum member and the resin member, it is lighter than the back door made entirely of aluminum.

Furthermore, the resin member is bonded to the resin coating layer side surface of the aluminum base material of the aluminum member, and the resin coating layer is laminated on the surface-treated surface of the aluminum base material. Since at least one layer is formed from the resin composition containing the in-situ polymerization type phenoxy resin, the bonding strength between the aluminum member and the resin member is high.

In the above items 2 to 5, the bonding strength between the aluminum member and the resin member can be reliably increased.

In 6 above, since the aluminum base material has a high tensile strength and a high Young's modulus, the thickness of the back door can be reduced, which contributes to the weight reduction of the back door.

In item 7 above, since the aluminum base material has high tensile strength and high Young's modulus, the thickness of the back door can be reduced, which contributes to the weight reduction of the back door.

In the above item 8, since the frame is an aluminum member, the rigidity of the back door can be increased. Furthermore, since each panel is made of resin, the weight of the back door can be reduced.

In the above item 9, the number of manufacturing steps of the back door can be reduced.

FIG. 1 is a schematic front view of an automobile back door according to one embodiment of the present invention. FIG. 2 is an end view taken along the line AA in FIG. 1. FIG. FIG. 3 is a schematic perspective view showing a state in which the back door is separated into an inner panel, a frame and an outer panel. FIG. 4 is a schematic cross-sectional view showing a state in which an aluminum member (frame) is arranged in a mold when the first resin member (inner panel) is molded by injection molding. FIG. 5 is a schematic cross-sectional view showing a state in which the aluminum member (frame) is arranged in the mold when molding the second resin member (outer panel) by injection molding. FIG. 6 is a schematic cross-sectional view showing a state in which a resin coating layer is formed on the surface-treated surface of the aluminum base material of the aluminum member. FIG. 7 is a schematic cross-sectional view of a state in which the aluminum member and the resin member are joined together. FIG. 8 is a schematic cross-sectional view of a state in which the aluminum member and the resin member are joined via an adhesive layer.

Next, embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, an automobile back door 10 according to one embodiment of the present invention is used by opening and closing when loading and unloading luggage in the rear luggage compartment of a hatchback type automobile.

In addition, reference numeral "31" in FIG.

As shown in FIGS. 2 and 3, the back door 10 includes an inner panel 21 made of resin arranged inside the vehicle body (in detail, the cargo room of the vehicle body), and an outer panel 22 made of resin arranged outside the vehicle body. It has an aluminum frame 11 arranged between the panels 21 and 22, and has a sandwich structure in which the inner panel 21 and the outer panel 22 are integrated with the frame 11 sandwiched between the panels 21 and 22. ing. The overall shape of the frame 11 is substantially in the shape of a Japanese character.

In the back door 10, the aluminum member 1 constitutes the frame 11 described above, and the resin member 8 constitutes the panels 21 and 22 described above. Therefore, the frame 11 is made of the aluminum member 1 and the panels 21 and 22 are made of the resin member 8 .

Since the panels 21 and 22 of the back door 10 are made of the resin member 8 as described above, the weight of the back door 10 is reliably reduced.

Further, the back door 10 is connected to the vehicle body via a door hinge (not shown) provided at the upper end thereof, and when the back door 10 is opened, the back door 10 is supported by the door hinge in a cantilever manner. Therefore, the back door 10 is required to have high rigidity. Therefore, in order to supplement the rigidity of the back door 10, the frame 11 is sandwiched between both panels 21 and 22 of the back door 10. - 特許庁Furthermore, the frame 11 and the panels 21 and 22 are joined (adhered) to further increase the rigidity of the back door 10 . Therefore, the rigidity required for the back door 10 can be satisfied without necessarily forming a reinforcing rib on the frame 11 . Therefore, it is easy to manufacture the frame 11 .

Next, the configuration of each member of the back door 10 and the manufacturing method thereof will be described in detail. In addition, below, the frame 11 is also described as the "aluminum member 1", and each panel (the inner panel 21 and the outer panel 22) is also described as the "resin member 8". Furthermore, regarding the resin member 8, when distinguishing between the resin member 8 that constitutes the inner panel 21 and the resin member 8 that constitutes the outer panel 22, the former is referred to as the "first resin member 8A" and the latter as the "second resin member 8A". Also referred to as "member 8B".

[Aluminum member 1]
The aluminum member 1 (frame 11) has an aluminum substrate 2 and one or more resin coating layers 4 laminated on the surface of the aluminum substrate 2, as shown in FIG.

Specifically, the resin coating layer 4 is laminated on the surface-treated surface of the aluminum substrate 2, and at least one layer of the resin coating layer 4 is formed from a resin composition containing an in-situ polymerizable phenoxy resin. there is

The surface-treated surface of the aluminum base material 2 is, as shown in FIG. Specifically, it is a contact surface 11 a of the frame 11 with the inner panel 21 and a contact surface 11 b of the frame 11 with the outer panel 22 . In the present invention, the surface-treated surface of the aluminum substrate 2 may be, for example, the entire surface of the aluminum substrate 2 .

In the aluminum member 1 , the resin coating layer 4 is laminated on the aluminum substrate 2 , so that the aluminum substrate 2 is provided with excellent bondability (adhesiveness) to the resin member 8 . Therefore, the resin coating layer 4 is the primer layer 5 of the aluminum substrate 2 .

Here, the primer layer 5 is interposed between the aluminum base material 2 and the resin member 8 when the aluminum member 1 and the resin member 8 are bonded, and the bondability of the aluminum base material 2 to the resin member 8 ( It means that it is a layer that improves adhesion).

The aluminum member 1 will be further detailed.

As shown in FIG. 6, the aluminum member 1 is provided with the functional group adhesion layer 3 on the surface of the surface treatment portion 2a formed on the surface of the aluminum base material 2, and the surface of the functional group adhesion layer 3 is coated with a resin. It comprises a structure in which a layer 4 is formed. Therefore, the functional group adhering layer 3 is formed between the surface-treated portion 2 a of the aluminum substrate 2 and the resin coating layer 4 .

In the present invention, the functional group adhering layer 3 may not necessarily be formed between the surface-treated portion 2a of the aluminum substrate 2 and the resin coating layer 4. That is, the resin coating layer 4 may be directly laminated on the surface of the surface-treated portion 2a of the aluminum base material 2 .

<Aluminum base material 2>
The type of aluminum material of the aluminum base material 2 is not limited, and for example, the aluminum content is 50% by mass or more. A6110), A4000 series alloys, A1000 series alloys, A390 series alloys, etc., and the aluminum material is more preferably an aluminum alloy having a Si content of 10 to 14% by mass.

In particular, the aluminum substrate 2 is made of an extruded aluminum profile of an A6000 series alloy, and preferably has properties such as a tensile strength of 240 MPa or more and a Young's modulus of 65 GPa or more. In this case, since the aluminum base material 2 has high tensile strength (high strength) and high Young's modulus (high rigidity), the thickness of the back door 10 can be reduced, so that the weight of the back door 10 can be reduced. contribute to The upper limit of tensile strength is not limited, and is, for example, 400 MPa. The upper limit of Young's modulus is not limited, and is, for example, 70 GPa.

Further, it is preferable that the aluminum base material 2 is made of an aluminum forged material of an A4000 series alloy and has properties such as a tensile strength of 350 MPa or more and a Young's modulus of 70 GPa or more. In this case, since the aluminum base material 2 has a very high tensile strength (high strength) and a very high Young's modulus (high rigidity), the thickness of the back door 10 can be further reduced. This greatly contributes to weight reduction of the back door 10 . The upper limit of tensile strength is not limited, and is, for example, 480 MPa. The upper limit of Young's modulus is not limited, and is, for example, 80 GPa.

When the aluminum base material 2 is made of aluminum forging, the aluminum base material 2 is preferably manufactured by the following method.

That is, in a preferred method for manufacturing the aluminum base material 2, a step of continuously casting a cast rod by supplying molten metal of an aluminum material having predetermined characteristics to a continuous casting apparatus, and cutting the cast rod into predetermined lengths. A process of obtaining a billet (raw material) by homogenizing the billet, a process of chamfering the outer diameter of the billet, and hot die forging the billet to obtain a roughly flat plate bar shape as a forging material. The step of forming the material is performed in the order of this description. Next, welding groove processing is applied to predetermined locations (both ends, etc.) of the cast material by machining (e.g., cutting), and predetermined locations of the cast material (surfaces to be joined with the resin member 8, etc.) ) is finished by machining (eg, cutting). A plurality of such preforms are produced, and these are joined by MIG welding, friction stir welding, or the like so as to form a substantially Japanese letter shape. As a result, the aluminum base material 2 made of the forged aluminum material is obtained.

<Surface treatment (part)>
A surface-treated portion 2 a is formed at least on the surface of the aluminum base material 2 to be bonded to the resin member 8 . Note that the surface-treated portion 2 a is regarded as part of the aluminum base material 2 .

Examples of the surface treatment include cleaning/degreasing treatment with a solvent or the like, blasting treatment, polishing treatment, etching treatment, chemical conversion treatment (eg, boehmite treatment, zirconium treatment), and the like. Treatment is preferred. Only one type of these treatments may be used, or two or more types may be applied. As specific methods for these surface treatments, known methods can be used.

The surface treatment is to clean the surface of the aluminum substrate 2 and to roughen the surface of the aluminum substrate 2 by forming fine irregularities for the purpose of anchoring effect. Therefore, the surface treatment can improve the bondability (adhesion) between the surface of the aluminum base material 2 and the resin coating layer 4 , and can also contribute to the improvement of the bondability with the resin member 8 .

Therefore, when manufacturing the aluminum member 1 , the surface treatment of the aluminum base 2 is performed before forming the resin coating layer 4 . As the surface treatment, at least one selected from the group consisting of blasting, polishing, etching and chemical conversion is particularly preferable.

[Cleaning and degreasing]
Examples of the cleaning or degreasing treatment with a solvent or the like include a method of degreasing the surface of the aluminum base material 2 by cleaning or wiping with an organic solvent such as acetone or toluene. A cleaning or degreasing treatment is preferably performed before any other surface treatment.

[Blasting]
Examples of blasting include shot blasting and sandblasting.

[Polishing]
Examples of the polishing treatment include buffing using an abrasive cloth, roll polishing using abrasive paper (sandpaper), electropolishing, and the like.

[Etching process]
Examples of the etching treatment include chemical etching treatments such as an alkali method, a phosphoric acid-sulfuric acid method, a fluoride method, a chromic acid-sulfuric acid method, and an iron salt method, and electrochemical etching treatments such as an electrolytic etching method. mentioned.

In particular, the etching treatment is preferably an alkali method using an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution, and more preferably a caustic soda method using an aqueous sodium hydroxide solution.

As the alkali method, for example, the aluminum substrate 2 is immersed in an aqueous solution (etching solution) of sodium hydroxide or potassium hydroxide having a concentration of 3 to 20% by mass at 20 to 70° C. for 1 to 15 minutes. can be done. As additives, a chelating agent, an oxidizing agent, a phosphate, or the like may be added to the etching solution. After the immersion, it is preferable to neutralize (desmut) with a 5 to 20 mass % nitric acid aqueous solution or the like, wash with water, and dry.

[Chemical treatment]
The chemical conversion treatment is to form a chemical conversion coating mainly on the surface of the aluminum base material 2 as the surface treated portion 2a.

Examples of the chemical conversion treatment include boehmite treatment and zirconium treatment, with boehmite treatment being particularly preferred.

In the boehmite treatment, a boehmite film is formed on the surface of the aluminum base material 2 by subjecting the aluminum base material 2 to a hot water treatment. As a reaction accelerator, ammonia, triethanolamine, or the like may be added to water. In particular, it is preferable to immerse the aluminum substrate 2 in hot water of 90 to 100° C. containing triethanolamine at a concentration of 0.1 to 5.0% by mass for 3 seconds to 5 minutes.

In the zirconium treatment, a film of a zirconium compound is formed on the surface of the aluminum substrate 2 by immersing the aluminum substrate 2 in a solution containing a zirconium salt such as zirconium phosphate. In particular, the aluminum substrate 2 is immersed for 0.5 to 3 minutes in a chemical agent for zirconium treatment (for example, "Palcoat 3762", "Palcoat 3796", etc. manufactured by Nihon Parkerizing Co., Ltd.) at 45 to 70°C. It is preferable to Zirconium treatment is preferably performed after etching treatment by the caustic soda method.

<Functional group adhesion layer 3>
The functional group adhering layer 3 is laminated between the surface-treated surface of the aluminum substrate 2 and the resin coating layer 4 in contact with both. The functional group-adhering layer 3 is preferably a layer having a functional group introduced from at least one selected from the group consisting of silane coupling agents, isocyanate compounds and thiol compounds.

Since the layer having the functional group is formed between the surface-treated surface of the aluminum substrate 2 and the resin coating layer 4, the chemical bond formed by the reaction of the functional group causes the aluminum substrate 2 to The effect of improving the bondability between the surface of and the resin coating layer 4 can be obtained, and it can also contribute to the improvement of the bondability with the resin member 8 .

Therefore, when manufacturing the aluminum member 1, before forming the resin coating layer 4, the surface-treated surface of the aluminum substrate 2 is coated with at least one selected from the group consisting of silane coupling agents, isocyanate compounds and thiol compounds. It is preferable to form the functional group adhesion layer 3 on the surface-treated surface of the aluminum substrate 2 by treating with seeds.

Since the surface-treated portion 2a is formed on the aluminum base material 2, the synergistic effect of the anchor effect due to the fine unevenness of the surface-treated portion 2a and the chemical bond formed by the reaction of the functional group of the functional group adhesion layer 3 is formed. As a result, the bondability between the surface of the aluminum base material 2 and the resin coating layer 4 and the bondability with the resin member 8 can be improved.

A method for forming the functional group-adhering layer 3 using a silane coupling agent, an isocyanate compound, or a thiol compound is not particularly limited, but examples thereof include a spray coating method and an immersion method. Specifically, the aluminum substrate 2 is immersed in a solution of a silane coupling agent or the like having a concentration of 5 to 50% by mass at room temperature to 100° C. for 1 minute to 5 days, and then at room temperature to 100° C. for 1 minute to 5 days. It can be carried out by a method such as time drying.

〔Silane coupling agent〕
As the silane coupling agent, for example, a known agent used for surface treatment of glass fibers can be used. A silanol group produced by hydrolyzing a silane coupling agent or a silanol group obtained by oligomerization of the silanol group reacts with and bonds with a hydroxyl group present on the surface-treated surface of the aluminum substrate 2 to form a resin coating layer 4. A functional group based on the structure of the silane coupling agent capable of chemically bonding with the resin member 8 can be imparted (introduced) to the aluminum substrate 2 .

Examples of the silane coupling agent include, but are not limited to, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyl. dimethoxysilane, 3-glycidoxypropylmethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltri Methoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N -2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3 -triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminopropyltrimethoxysilane hydrochloride, tris -(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, dithioltriazinepropyltriethoxysilane and the like. These may be used individually by 1 type, or may use 2 or more types together.

[Isocyanate compound]
According to the isocyanate compound, the isocyanate group in the isocyanate compound reacts with and bonds with the hydroxyl groups present on the surface-treated surface of the aluminum base material 2, so that it can chemically bond with the resin coating layer 4 and the resin member 8. A functional group based on the structure of the isocyanate compound can be imparted (introduced) to the aluminum substrate 2 .

The isocyanate compound is not particularly limited. 2-isocyanate ethyl methacrylate (e.g., Showa Denko KK "Karenzu MOI (registered trademark)"), which is an isocyanate compound having a radical reactive group, 2-isocyanate ethyl acrylate (e.g., Showa Denko KK "Karenzu AOI ( registered trademark)”, the same “AOI-VM (registered trademark)”), 1,1-(bisacryloyloxyethyl) ethyl isocyanate (for example, “Karenzu BEI (registered trademark)” manufactured by Showa Denko K.K.) and the like. .

[thiol compound]
According to the thiol compound, the mercapto group (thiol group) in the thiol compound reacts with and bonds with the hydroxyl group present on the surface-treated surface of the aluminum substrate 2, thereby forming the resin coating layer 4 and the resin member 8. A functional group based on the structure of the thiol compound that can chemically bond with can be imparted (introduced) to the aluminum substrate 2 .

The thiol compound is not particularly limited, but for example, pentaerythritol tetrakis (3-mercaptopropionate) (eg, "QX40" manufactured by Mitsubishi Chemical Corporation, "QE-340M" manufactured by Toray Fine Chemicals Co., Ltd.) ), ether-based primary thiol (e.g., Cognis "Cup Cure 3-800"), 1,4-bis (3-mercaptobutyryloxy) butane (e.g., Showa Denko K.K. "Karenzu MT ( registered trademark) BD1”), pentaerythritol tetrakis (3-mercaptobutyrate) (for example, Showa Denko Co., Ltd. “Kalenz MT (registered trademark) PE1”), 1,3,5-tris(3-mercaptobutyloxyethyl )-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (eg, “Karenzu MT (registered trademark) NR1” manufactured by Showa Denko KK) and the like.

<Resin coating layer 4>
The resin coating layer 4 is laminated on the surface-treated surface of the aluminum substrate 2 , that is, on the surface of the surface-treated portion 2 a of the aluminum substrate 2 . Alternatively, it may be laminated on the surface of the functional group adhesion layer 3 as described above.

Moreover, the resin coating layer 4 may be composed of a single layer, or may be composed of a plurality of layers of two or more layers.

The resin coating layer 4 is formed on the surface-treated surface of the aluminum substrate 2 with excellent bondability (adhesiveness), protects the surface of the aluminum substrate 2, and protects the surface of the aluminum substrate 2. Deterioration such as adhesion of dirt and oxidation can be suppressed.

Moreover, the resin coating layer 4 can provide the surface of the aluminum base material 2 with excellent bondability with the resin member 8 . Furthermore, with the surface of the aluminum base 2 protected as described above, it is also possible to obtain the aluminum member 1 capable of maintaining excellent bondability over a long period of several months.

As described above, in the aluminum member 1, the resin coating layer 4 can provide the aluminum substrate 2 with excellent bondability to the resin member 8. Therefore, the resin coating layer 4 serves as a primer for the aluminum substrate 2 as described above. layer 5;

(On-site polymerization type phenoxy resin)
At least one layer of the resin coating layer 4 is a layer formed from a resin composition containing an in-situ polymerizable phenoxy resin (hereinafter also referred to as an in-situ polymerizable phenoxy resin layer).

In-situ polymerizable phenoxy resins are resins that are also called thermoplastic epoxy resins, in-situ curable phenoxy resins, in-situ curable epoxy resins, etc. A bifunctional epoxy resin and a bifunctional phenol compound undergo a polyaddition reaction in the presence of a catalyst. to form a thermoplastic structure, ie a linear polymer structure. That is, unlike a thermosetting resin that forms a three-dimensional network with a crosslinked structure, it is possible to form a resin coating layer 4 having thermoplasticity.

Since the in-situ polymerization type phenoxy resin has such characteristics, it is possible to form the resin coating layer 4 having excellent bonding properties with the aluminum substrate 2 by in-situ polymerization, and the resin coating The layer 4 can be made excellent in bondability with the resin member 8 .

Therefore, when manufacturing the aluminum member 1, at least one layer of the resin coating layer 4 is formed by subjecting the resin composition containing the in-situ polymerization type phenoxy resin to a polyaddition reaction on the surface-treated surface of the aluminum base material 2. preferably formed.

The polyaddition reaction of the resin composition containing the in-situ polymerizable phenoxy resin is preferably carried out on the surface of the functional group-attached layer 3, and may also be carried out on the surface of the resin coating layer 4 other than the in-situ polymerizable phenoxy resin layer. is also preferred. The resin coating layer including the in-situ polymerizable phenoxy resin layer formed in this manner has excellent bondability with the aluminum substrate 2 and excellent bondability with the resin member 8 .

A coating method for forming the resin coating layer 4 with the resin composition is not particularly limited, but examples thereof include a spray coating method and an immersion method.

In order to allow the polyaddition reaction of the in-situ polymerizable phenoxy resin to proceed sufficiently and form the desired resin coating layer 4, the resin composition may contain a solvent and, if necessary, an additive such as a coloring agent. good. In this case, among the components other than the solvent of the resin composition, it is preferable that the in-situ polymerization type phenoxy resin is the main component. The main component means that the content of the in-situ polymerizable phenoxy resin is 50 to 100% by mass. This content is preferably 60% by mass or more, and more preferably 80% by mass or more.

A combination of a bifunctional epoxy resin and a bifunctional phenolic compound is preferred as the polyaddition-reactive compound for obtaining the in-situ polymerizable phenoxy resin.

Bifunctional epoxy resins include bisphenol-type epoxy resins, biphenyl-type epoxy resins, and the like. Among these, one type may be used alone, or two or more types may be used in combination. Specifically, Mitsubishi Chemical Corporation "jER (registered trademark) 828", "jER (registered trademark) 834", "jER (registered trademark) 1001", "jER (registered trademark) 1004", "jER (registered trademark) YX-4000" and the like.

Bifunctional phenol compounds include bisphenol, biphenol and the like. Among these, one type may be used alone, or two or more types may be used in combination.

Combinations of these include bisphenol A type epoxy resin and bisphenol A, bisphenol A type epoxy resin and bisphenol F, biphenyl type epoxy resin and 4,4'-biphenol, and the like. Also, for example, a combination of "WPE190" and "EX-991L" manufactured by Nagase ChemteX Corporation can be mentioned.

Suitable catalysts for the polyaddition reaction of the in-situ polymerization type phenoxy resin include, for example, tertiary amines such as triethylamine and 2,4,6-tris(dimethylaminomethyl)phenol; phosphorous compounds such as triphenylphosphine; used for

The polyaddition reaction is preferably carried out by heating at 120 to 200° C. for 5 to 90 minutes, depending on the type of reaction compound. Specifically, the in-situ polymerization type phenoxy resin layer can be formed by coating the resin composition, appropriately volatilizing the solvent, and then performing a polyaddition reaction by heating.

(Thermosetting resin)
When the resin coating layer 4 is composed of multiple layers, at least one of the layers is preferably a layer formed from a resin composition containing a thermosetting resin (hereinafter also referred to as a thermosetting resin layer). . Thermosetting resins include urethane resins, epoxy resins, vinyl ester resins, unsaturated polyester resins, and the like.

Each layer of the thermosetting resin layer may be formed of one of these resins alone, or may be formed of a mixture of two or more of these resins. Alternatively, two or more layers may be different types of thermosetting resin layers.

The resin coating layer 4 has a laminated structure of an in-situ polymerization type phenoxy resin layer and a thermosetting resin layer, so that the resin coating layer has various properties such as strength and impact resistance based on the thermosetting resin. It is possible to configure the aluminum member 1 coated with.

The order of lamination of the thermosetting resin layer and the on-site polymerization type phenoxy resin layer is not particularly limited, but from the viewpoint of obtaining excellent bonding with the resin member 8, the on-site polymerization type phenoxy resin layer is used. , the outermost surface of the resin coating layer 4 is preferably laminated.

A coating method for forming at least one layer of the resin coating layer 4 with a resin composition containing a thermosetting resin is not particularly limited, but examples thereof include a spray coating method and an immersion method.

The resin composition may contain a solvent and, if necessary, an additive such as a coloring agent in order to allow the curing reaction of the thermosetting resin to proceed sufficiently to form a desired resin coating layer. In this case, it is preferable that the thermosetting resin is the main component among the components other than the solvent of the resin composition. A main component means that the content of the thermosetting resin is 50 to 100% by mass. This content is preferably 60% by mass or more, and more preferably 80% by mass or more.

In addition, the thermosetting resin referred to in the present invention broadly means a cross-linkable resin, and is not limited to the heat-curing type, and includes room-temperature curing type and light-curing type. The photo-curing type can be cured in a short time by irradiation with visible light or ultraviolet rays. The photo-curing type may be used in combination with the heat-curing type and/or the room temperature-curing type. Examples of the photo-curing type include vinyl ester resins such as “Lipoxy (registered trademark) LC-760” and “Lipoxy (registered trademark) LC-720” manufactured by Showa Denko K.K.

[Urethane resin]
A urethane resin is usually a resin obtained by a reaction between an isocyanato group and a hydroxyl group, and is preferably a urethane resin that corresponds to what is defined in ASTM D16 as "a coating material containing polyisocyanate with a non-volatile content of 10 wt% or more in a vehicle". . The urethane resin may be of a one-component type or a two-component type.

One-liquid type urethane resins include oil-modified type (cured by oxidation polymerization of unsaturated fatty acid groups), moisture-cured type (cured by reaction of isocyanato group with water in the air), block type (blocking agent is dissociated and regenerated by heating and cures by reacting with hydroxyl groups), lacquer type (cures by evaporation of the solvent and drying), and the like. Among these, moisture-curable one-liquid urethane resins are preferably used from the viewpoint of ease of handling and the like. Specifically, "UM-50P" manufactured by Showa Denko K.K.

Two-component urethane resins include catalyst-curing type (which cures by reacting isocyanato groups with water in the air in the presence of a catalyst), and polyol-curing type (which cures by reaction between isocyanato groups and hydroxyl groups of polyol compounds). what to do), etc.

Polyester polyols, polyether polyols, phenol resins, and the like are examples of polyol compounds in the polyol curing type.

Further, the isocyanate compound having an isocyanato group in the polyol curing type includes aliphatic isocyanates such as hexamethylene diisocyanate (HDI), tetramethylene diisocyanate, and dimer acid diisocyanate; 2,4- or 2,6-tolylene diisocyanate (TDI). or mixtures thereof, p-phenylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate (MDI) and aromatic isocyanates such as polymeric MDI which is a polynuclear mixture thereof; alicyclic isocyanates such as isophorone diisocyanate (IPDI), etc. .

As for the compounding ratio of the polyol compound and the isocyanate compound in the polyol-curable two-component urethane resin, the hydroxyl group/isocyanate group molar equivalent ratio is preferably in the range of 0.7 to 1.5.

Urethane catalysts used in two-component urethane resins include triethylenediamine, tetramethylguanidine, N,N,N',N'-tetramethylhexane-1,6-diamine, dimethyl etheramine, N,N,N ',N'',N''-Pentamethyldipropylene-triamine, N-methylmorpholine, bis(2-dimethylaminoethyl)ether, dimethylaminoethoxyethanol, triethylamine and other amine-based catalysts; dibutyltin diacetate, dibutyl Organotin-based catalysts such as tin dilaurate, dibutyltinthiocarboxylate, and dibutyltin dimaleate are included.

In the polyol curing type, it is generally preferable to blend 0.01 to 10 parts by mass of the urethanization catalyst with respect to 100 parts by mass of the polyol compound.

〔Epoxy resin〕
Epoxy resins are resins having at least two epoxy groups in one molecule.

Prepolymers of epoxy resins before curing include ether-based bisphenol-type epoxy resins, novolac-type epoxy resins, polyphenol-type epoxy resins, aliphatic-type epoxy resins, ester-type aromatic epoxy resins, cycloaliphatic epoxy resins, ether-type epoxy resins, Ester-based epoxy resins and the like can be mentioned, and among these, bisphenol A-type epoxy resins are preferably used. Among these, one type may be used alone, or two or more types may be used in combination.

Specific examples of the bisphenol A epoxy resin include "jER (registered trademark) 828" and "jER (registered trademark) 1001" manufactured by Mitsubishi Chemical Corporation.

Specific examples of the novolak-type epoxy resin include "D.E.N. (registered trademark) 438 (registered trademark)" manufactured by The Dow Chemical Company.

Curing agents used for epoxy resins include known curing agents such as aliphatic amines, aromatic amines, acid anhydrides, phenol resins, thiols, imidazoles, and cationic catalysts. When the curing agent is used in combination with a long-chain aliphatic amine and/or thiols, effects such as high elongation and excellent impact resistance can be obtained.

Specific examples of thiols include the same compounds as those exemplified as the thiol compounds in the surface treatment described above. Among these, pentaerythritol tetrakis(3-mercaptobutyrate) (for example, "Karenzu MT (registered trademark) PE1" manufactured by Showa Denko KK) is preferable from the viewpoint of elongation and impact resistance.

[Vinyl ester resin]
A vinyl ester resin is obtained by dissolving a vinyl ester compound in a polymerizable monomer (such as styrene). Also called epoxy (meth)acrylate resin, vinyl ester resin includes urethane (meth)acrylate resin.

As the vinyl ester resin, those described in "Polyester Resin Handbook" (Nikkan Kogyo Shimbun, 1988), "Paint Glossary" (Shikizai Kyokai, 1993), etc. can also be used. Specific examples include "Lipoxy (registered trademark) R-802", "Lipoxy (registered trademark) R-804", and "Lipoxy (registered trademark) R-806" manufactured by Showa Denko K.K. .

The urethane (meth)acrylate resin is obtained, for example, by reacting an isocyanate compound with a polyol compound and then reacting with a hydroxyl group-containing (meth)acrylic monomer (and, if necessary, a hydroxyl group-containing allyl ether monomer). Radically polymerizable unsaturated group-containing oligomers can be mentioned. Specific examples include "Lipoxy (registered trademark) R-6545" manufactured by Showa Denko K.K.

A vinyl ester resin can be cured by radical polymerization by heating in the presence of a catalyst such as an organic peroxide.

Examples of organic peroxides include, but are not limited to, ketone peroxides, peroxyketals, hydroperoxides, diallyl peroxides, diacyl peroxides, peroxyesters, peroxy and dicarbonates. By combining these with a cobalt metal salt or the like, curing at room temperature is also possible.

Examples of the cobalt metal salt include, but are not particularly limited to, cobalt naphthenate, cobalt octylate, cobalt hydroxide, and the like. Among these, cobalt naphthenate and/or cobalt octylate are preferred.

[Unsaturated polyester resin]
Unsaturated polyester resin is a condensation product (unsaturated polyester) obtained by an esterification reaction between a polyol compound and an unsaturated polybasic acid (and saturated polybasic acid if necessary) and a polymerizable monomer (such as styrene). dissolved in

As the unsaturated polyester resin, those described in "Polyester Resin Handbook" (Nikkan Kogyo Shimbun, 1988), "Paint Glossary" (Shikizai Kyokai, 1993), etc. can also be used. , and, more specifically, "Rigolac (registered trademark)" manufactured by Showa Denko K.K.

Unsaturated polyester resins can be cured by radical polymerization by heating in the presence of catalysts as for vinyl ester resins.

[Backdoor 10]
As shown in FIG. 7, in the back door 10, the surface 4a of the aluminum substrate 2 of the aluminum member 1 on the side of the resin coating layer 4 and the resin member 8 are joined. The resin coating layer 4 is the primer layer 5 of the aluminum substrate 2 as described above.

In this embodiment, more specifically, the surface 4a of the aluminum base material 2 of the aluminum member 1 on the side of the resin coating layer 4 and the resin member 8 are joined so as to be in direct contact with each other.

As described above, since the surface 4a on the side of the resin coating layer 4 has excellent bondability with the resin member 8, the back door 10 in which the aluminum member 1 and the resin member 8 are bonded with high bonding strength can be manufactured. be able to.

The thickness of the resin coating layer 4 (thickness after drying) depends on the type of resin of the resin member 8 and the bonding area, but excellent bondability with the resin member 8 on the surface 4a on the resin coating layer 4 side is obtained. From the point of view, it is preferably 1 μm to 10 mm, more preferably 2 μm to 8 mm, still more preferably 3 μm to 5 mm.

Specifically, when the aluminum member 1 and the carbon fiber reinforced resin member (CFRP member) as the resin member 8 are joined and integrated, the aluminum member 1 and the glass fiber reinforced resin member (GFRP member) as the resin member 8 are , the thickness of the resin coating layer 4 is preferably 0.1 to 10 mm, more preferably 0.2 to 8 mm, still more preferably 0.5 to 5 mm.

The type of resin of the resin member 8 is not limited, and general synthetic resin such as polypropylene may be used. Examples thereof include resins such as polycarbonate resins, polyester resins, modified polyphenylene ether resins, and polyetherimide resins, which are used in automobile parts. Also, the resin of the resin member 8 may be a resin containing reinforcing fibers (eg, carbon fiber, glass fiber). Examples of such resins include carbon fiber reinforced resins (CFRP), glass fiber reinforced resins (GFRP), and sheet molding compounds such as sheet molding compounds (SMC) and bulk molding compounds (BMC). be done.

SMC is a mixture of unsaturated polyester resin and / or vinyl ester resin, polymerizable unsaturated monomer, curing agent, low shrinkage agent and filler, etc. It is a sheet-shaped molded product obtained by impregnating a fiber).

As a method for manufacturing the back door 10, there is a method in which the aluminum member 1 and the resin member 8 which are separately produced are joined (adhered) to be integrated.

In particular, as a method of manufacturing the back door 10, a method of forming the resin member 8 and at the same time joining the aluminum member 1 and the resin member 8 together is preferable. Specifically, when molding the resin member 8 by a method such as an injection molding method (including an insert molding method), a transfer molding method, a press molding method, a filament winding molding method, a hand layup molding method, the aluminum member 1 By bonding the resin member 8 to the resin coating layer 4 side surface 4a of the aluminum base material 2, the aluminum member 1 and the resin member 8 are integrated, thereby obtaining the back door 10. In this case, the number of manufacturing steps of the back door 10 can be reduced.

Specifically, as shown in FIG. 4, the first resin member 8A (that is, the resin member 8 that constitutes the inner panel 21) and the second resin member 8B (that is, the resin member 8 that constitutes the outer panel 22) are In the case of molding by injection molding, for example, the aluminum member 1 (that is, the frame 11) is arranged in the injection molding die 40A, and the resin of the first resin member 8A is injected into the mold 40A by an injection device (not shown). By injecting (its injection direction 45A) into the cavity 41A, the first resin member 8A is molded, and at the same time, the aluminum member 1 and the first resin member 8A are joined.

After that, as shown in FIG. 5, the aluminum member 1 to which the first resin member 8A is joined is placed in an injection molding die 40B, and the resin of the second resin member 8B is injected into the metal by an injection device (not shown). The second resin member 8B is molded by injecting (its injection direction 45B) into the cavity 41B of the mold 40B, and at the same time the aluminum member 1 and the second resin member 8B are joined. The back door 10 is manufactured by the above method.

In Figures 4 and 5, reference numerals "44A" and "44B" are knock-out pins for ejecting the product from the mold.

In the present invention, in the method for manufacturing the back door 10 described above, the second resin member 8B may be molded after the first resin member 8A is molded as described above. The first resin member 8A may be molded after the resin member 8B is molded.

Next, another embodiment of the invention will be described below.

As shown in FIG. 8 , in the back door 10 , the surface 4 a of the aluminum base 2 of the aluminum member 1 on the side of the resin coating layer 4 and the resin member 8 may be joined together via an adhesive layer 7 . .

As described above, depending on the type of resin of the resin member 8, the back door 10 in which the aluminum member 1 and the resin member 8 are joined with higher joint strength can be obtained by using an adhesive.

The adhesive for the adhesive layer 7 is appropriately selected according to the type of resin of the resin member 8. For example, known adhesives such as epoxy resin, urethane resin, and vinyl ester resin may be used. can.

Depending on the heating temperature during bonding (adhesion), the back door 10 may be thermally deformed due to the difference in thermal expansion coefficient between the aluminum base material 2 and the resin member 8 in the process of cooling to room temperature after bonding (adhesion). is more likely to occur. From the viewpoint of suppressing and alleviating such thermal deformation, the thickness of the adhesive layer 7 is set so that the total thickness of the resin coating layer 4 and the adhesive layer 7 is 4 μm or more. It is desirable to provide a portion having a large elongation rate between the base 8 and the base 8 with a predetermined thickness. The above-mentioned total thickness may be determined by considering physical properties such as the elongation rate of the resin coating layer 4 and the adhesive layer 7 when the temperature changes during bonding (temperature changes from heating temperature during bonding to room temperature cooling). preferable. A preferred upper limit for the total thickness is 10 mm.

Here, when the aluminum member 1 and the resin member 8 are joined together, the layer that joins the two members 1 and 8 is called a joint layer, and the thickness thereof is called the thickness of the joint layer. Therefore, when the adhesive layer 7 is formed on the surface 4a of the aluminum member 1 on the side of the resin coating layer 4, both layers 4 and 7 of the resin coating layer 4 and the adhesive layer 7 are bonding layers. The combined thickness of layers 4 and 10 is the thickness of the bonding layer. Further, when the adhesive layer 7 is not formed on the surface 4a of the aluminum member 1 on the side of the resin coating layer 4, the resin coating layer 4 is the bonding layer, and the thickness of the resin coating layer 4 is the thickness of the bonding layer. is.

Although several embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist of the present invention.

For example, in the above-described embodiment, the number of resin members joined to the aluminum member is two, but in the present invention, the number of resin members is not limited to two. It may be one or plural.

Practical test examples and comparative test examples related to the present invention are shown below. However, the present invention is not limited to the following practical test examples.

<Test Example 1>
An aluminum plate as an aluminum substrate was molded by hot die forging. Therefore, the aluminum plate is made of forged material. Then, the surface of the aluminum plate was smoothed by machining.

The aluminum material of the aluminum plate is an aluminum alloy "AHS (registered trademark)-1" manufactured by Showa Denko K.K. Fe: 0.23% by mass, Cu: 2.0% by mass, Mg: 0.6% by mass, and the balance being Al and unavoidable impurities. , and its Young's modulus was 78 GPa.

The dimensions of the aluminum plate were 100 mm in length, 25 mm in width and 1.6 mm in thickness.

(Surface treatment process)
An aluminum plate (that is, an aluminum substrate) is immersed in an aqueous sodium hydroxide solution with a concentration of 5% by mass for 1.5 minutes, neutralized with an aqueous nitric acid solution with a concentration of 5% by mass, washed with water, and dried to perform an etching treatment. did

Next, the aluminum plate after the etching treatment is boiled for 3 minutes in an aqueous solution containing 0.3% by mass of triethanolamine to perform a boehmite treatment. A boehmite film having

(Functional group adhesion layer forming step)
Next, 3-methacryloxypropyltrimethoxysilane (“KBM-503” manufactured by Shin-Etsu Silicone Co., Ltd.; silane coupling agent) 2.48 g (0.01 mol) was dissolved in 1000 g of industrial ethanol at 80 ° C. The boehmite-treated aluminum plate was immersed in the solution containing the coupling agent for 3 minutes. After that, the aluminum plate was taken out and dried to form a functional group adhering layer on the surface of the boehmite film (surface treatment portion).

(Resin coating layer forming step)
Next, a one-component urethane resin (“UM-50P” manufactured by Showa Denko K.K.) was applied to the surface of the functional group adhesion layer of the aluminum plate by a spray method so that the thickness after drying was 15 μm. . Then, the solvent was volatilized and cured by leaving it in the air at normal temperature for 24 hours to form a first resin coating layer (thermosetting resin layer).

Furthermore, on the surface of the thermosetting resin layer, 100 g of epoxy resin (“jER (registered trademark) 1004” manufactured by Mitsubishi Chemical Corporation), 12.6 g of bisphenol A, and 0.45 g of triethylamine are dissolved in 209 g of acetone. The in-situ polymerization type phenoxy resin composition was applied by a spray method so that the thickness after drying was 10 μm. After the solvent is volatilized by leaving it in the air at normal temperature for 30 minutes, it is left in a furnace at 150° C. for 30 minutes for a polyaddition reaction and allowed to cool to normal temperature, thereby forming the second layer resin. A coating layer (in-situ polymerization type phenoxy resin layer) was formed.

A plate having a resin coating layer consisting of two layers, a 15 μm thick thermosetting resin layer and a 10 μm thick in-situ polymerizable phenoxy resin layer, formed on the surface of the functional group adhesion layer of the aluminum plate by the above method. A shaped aluminum member was produced.

(Joining process)
Next, the aluminum member is placed in a mold for injection molding, and a bulk molding compound (BMC) (“Rigolac (registered trademark) RNC-980” manufactured by Showa Denko Co., Ltd.) is applied to the surface of the resin coating layer of the aluminum member. ) is injection-molded by an injection molding machine (“α-S100iA” manufactured by Fanuc Corporation; mold temperature 160 ° C., molding pressure 100 MPa, molding time 3 minutes) to form an aluminum member and resin The members were joined together to produce an aluminum-resin joined body A.

In joined body A, the dimensions of the resin member were 45 mm in length, 10 mm in width and 3 mm in thickness, and the length of the joint between the aluminum member and the resin member was 5 mm.

Also, the aluminum member was stored in the air at room temperature for 3 months, and then the aluminum member and the resin member were joined in the same manner as described above, whereby an aluminum-resin joined body B was produced.

<Comparative Test Example 1>
An aluminum member (without a resin coating layer) was prepared by sequentially performing a surface treatment step and a functional group adhesion layer forming step in the same manner as in Test Example 1. Then, an attempt was made to join the aluminum member and the resin member by injection-molding a plate-shaped resin member made of BMC in the same manner as in Example 1 on the surface of the functional group adhesion layer of the aluminum member. After molding the resin member, when both members were removed from the mold, the aluminum member and the resin member were not joined and the resin member fell off.

<Test Example 2>
(Surface treatment process)
The same aluminum plate as in Experimental Example 1 was prepared. Then, the aluminum plate was subjected to a surface treatment step in the same manner as in Experimental Example 1, thereby forming a surface-treated portion (boehmite film having surface unevenness) on the surface of the aluminum plate.

(Functional group adhesion layer forming step)
Next, instead of 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Silicone Co., Ltd. "KBM-5103"; silane cup A functional group adhering layer was formed in the same manner as in Experimental Example 1, except that 2.34 g (0.01 mol) of ring agent) was used.

(Resin coating layer forming step)
Next, a visible light-curable vinyl ester resin (“Lipoxy (registered trademark) LC-720” manufactured by Showa Denko KK) was applied to the surface of the functional group adhesion layer of the aluminum plate so that the thickness after drying was 15 μm. After coating the surface of the aluminum plate by a spray method, the first resin coating layer (thermal A curable resin (photocurable type) layer) was formed.

Furthermore, on the surface of the thermosetting resin layer, 100 g of epoxy resin (“jER (registered trademark) 1004” manufactured by Mitsubishi Chemical Corporation), 12.6 g of bisphenol A, and 0.45 g of triethylamine are dissolved in 209 g of acetone. The in-situ polymerization type phenoxy resin composition was applied by a spray method so that the thickness after drying was 10 μm. After the solvent is volatilized by leaving it in the air at normal temperature for 30 minutes, it is left in a furnace at 150° C. for 30 minutes for a polyaddition reaction and allowed to cool to normal temperature, thereby forming the second layer resin. A coating layer (in-situ polymerization type phenoxy resin layer) was formed.

By the above method, a plate-shaped resin coating layer consisting of two layers of a thermosetting resin layer with a thickness of 15 μm and an in-situ polymerization type phenoxy resin with a thickness of 10 μm was formed on the surface of the functional group adhesion layer of the aluminum plate. An aluminum member was produced.

(Adhesive layer forming step)
Next, on the surface of the resin coating layer of the aluminum member, a room-temperature curing adhesive was applied in a layered manner so as to have a thickness of 30 μm. Then, the adhesive layer was cured by being left in the air at room temperature for 24 hours.

In addition, as the room temperature curing adhesive, 100 g of bisphenol A type epoxy resin (“jER (registered trademark) 828” manufactured by Mitsubishi Chemical Corporation), pentaerythritol tetrakis (3-mercaptobutyrate) (manufactured by Showa Denko K.K. “Karenzu MT (Registered Trademark) PE1”; curing agent) and 10 g of 2,4,6-tris(dimethylaminomethyl)phenol were mixed to prepare a room-temperature curing adhesive.

(Joining process)
Next, on the surface of the adhesive layer of the aluminum member, by injection molding a plate-shaped resin member made of BMC in the same manner as in Example 1, the aluminum member and the resin member are joined, thereby aluminum-resin joining. Body A was produced.

Also, the aluminum member was stored in the air at room temperature for 3 months, and then the aluminum member and the resin member were joined in the same manner as described above, whereby an aluminum-resin joined body B was produced.

<Comparative Test Example 2>
An aluminum member (without a resin coating layer) was prepared by sequentially performing the surface treatment step and the functional group adhesion layer forming step in the same manner as in Test Example 2. On the surface of the functional group adhering layer of this aluminum member, a room temperature curing adhesive was applied in a layered manner in the same manner as in Example 2. Then, the adhesive layer was cured by being left in the air at room temperature for 24 hours. Next, the aluminum member and the resin member were joined in the same manner as in Example 2, thereby producing an aluminum-resin joined body A.

Also, an aluminum member (without a resin coating layer) was stored in air at room temperature for 3 months, and then the aluminum member and the resin member were joined in the same manner as described above, thereby producing an aluminum-resin joined body B.

[Evaluation of bonding properties]
After leaving the aluminum-resin bonded bodies prepared in Examples 1 and 2 and Comparative Test Examples 2 above at room temperature for 1 day, a tensile tester (manufactured by Shimadzu Corporation) was used in accordance with ISO 19095 1-4. A tensile shear bonding strength test was performed using a testing machine Autograph "AG-IS"; load cell 10 kN, tensile speed 10 mm/min, temperature 23° C., 50% RH) to measure bonding strength. These results are shown in Table 1.

The meanings of the symbols in the "joining strength evaluation" column in Table 1 are as follows.

○: Bonding strength is 20 MPa or more ×: Bonding strength is less than 20 MPa -: The aluminum member and the resin member are not bonded.

<Test Example 3>
(Surface treatment process)
The same aluminum plate as in Experimental Example 1 was prepared. Then, the aluminum plate was subjected to a surface treatment step in the same manner as in Experimental Example 1, thereby forming a surface-treated portion (boehmite film having surface unevenness) on the surface of the aluminum plate.

(Functional group adhesion layer forming step)
Next, 2 g of 3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Silicone Co., Ltd. "KBM-903"; silane coupling agent) was dissolved in 1000 g of industrial ethanol at 70° C. in a silane coupling agent-containing solution. The treated aluminum plate was immersed for 3 minutes. After that, the aluminum plate was taken out and dried to form a functional group adhering layer on the surface of the boehmite film (surface treatment portion).

(Resin coating layer forming step)
Next, an in situ polymerization type phenoxy resin composition prepared by dissolving 100 g of an epoxy resin (“jER (registered trademark) 1001” manufactured by Mitsubishi Chemical Corporation), 24 g of bisphenol A, and 0.4 g of triethylamine in 250 g of acetone, It was applied to the surface of the functional group adhering layer of the aluminum plate by a spray method so that the thickness after drying was 10 μm. After the solvent is volatilized by leaving it in the air at room temperature for 30 minutes, it is left in a furnace at 150° C. for 30 minutes for a polyaddition reaction and allowed to cool to room temperature, thereby forming the first layer resin. A coating layer (in-situ polymerization type phenoxy resin layer) was formed.

Furthermore, on the surface of the in-situ polymerization type phenoxy resin layer, 100 g of a vinyl ester resin (“Lipoxy (registered trademark) R-6540” manufactured by Showa Denko Co., Ltd.; tensile elongation of 20%), 0.5 g of cobalt octylate, and an organic peroxide A thermosetting resin composition prepared by mixing 1.5 g of an oxide catalyst (manufactured by Kayaku Akzo Co., Ltd., "Hardener 328E") is applied by a spray method and cured at room temperature by repeating the operation several times. , a second resin coating layer (thermosetting resin (normal temperature curing type) layer) having a thickness of 2 mm was formed.

By the above method, a plate having a resin coating layer consisting of two layers, a 10 μm-thick in-situ polymerizable phenoxy resin layer and a 2 mm-thick thermosetting resin layer, formed on the surface of the functional group-attached layer of the aluminum plate. A shaped aluminum member was produced.

(Adhesive layer forming step)
Next, on the surface of the resin coating layer of the aluminum member, a room-temperature curing adhesive was applied in a layered manner so as to have a thickness of 20 μm. Then, the adhesive layer was cured by being left in the air at room temperature for 24 hours.

In addition, as the room temperature curing adhesive, 100 g of bisphenol A type epoxy resin (“jER (registered trademark) 828” manufactured by Mitsubishi Chemical Corporation), pentaerythritol tetrakis (3-mercaptobutyrate) (manufactured by Showa Denko K.K. “Karenzu MT (Registered Trademark) PE1”; curing agent) and 10 g of 2,4,6-tris(dimethylaminomethyl)phenol were mixed to prepare a room-temperature curing adhesive.

(Joining process)
Next, on the surface of the adhesive layer of the aluminum member, by injection molding a plate-shaped resin member made of BMC in the same manner as in Example 1, the aluminum member and the resin member are joined, thereby aluminum-resin joining. made the body.

<Comparative Test Example 3>
An aluminum member (without a resin coating layer) was prepared by sequentially performing a surface treatment step and a functional group adhesion layer forming step in the same manner as in Test Example 3. On the surface of the functional group adhering layer of this aluminum member, a room temperature curing adhesive was applied in a layered manner in the same manner as in Example 3. Then, the adhesive layer was cured by being left in the air at room temperature for 24 hours. Next, the aluminum member and the resin member were joined in the same manner as in Example 3, thereby producing an aluminum-resin joined body.

<Test Example 4>
(Surface treatment process)
The same aluminum plate as in Experimental Example 1 was prepared. Then, the aluminum plate was immersed in an aqueous sodium hydroxide solution with a concentration of 5% by mass for 1.5 minutes, neutralized with an aqueous nitric acid solution with a concentration of 5% by mass, washed with water, and dried to perform an etching treatment. .

Next, the aluminum plate after the etching treatment is boiled in pure water for 10 minutes and then baked at 250° C. for 10 minutes to perform boehmite treatment. A boehmite film having a

(Functional group adhesion layer forming step)
Next, 2 g of 3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Silicone Co., Ltd. "KBM-903"; silane coupling agent) was dissolved in 1000 g of industrial ethanol at 70° C. in a silane coupling agent-containing solution. The treated aluminum plate was immersed for 20 minutes. After that, the aluminum plate was taken out and dried to form a functional group adhering layer on the surface of the boehmite film (surface treatment portion).

(Resin coating layer forming step)
Next, an in situ polymerization type phenoxy resin composition prepared by dissolving 100 g of an epoxy resin (“jER (registered trademark) 1001” manufactured by Mitsubishi Chemical Corporation), 24 g of bisphenol A, and 0.4 g of triethylamine in 250 g of acetone, It was applied to the surface of the functional group adhering layer of the aluminum plate by a spray method so that the thickness after drying was 90 μm. Then, after volatilizing the solvent by leaving it in the air at room temperature for 30 minutes, it is left in a furnace at 150 ° C. for 30 minutes to perform a polyaddition reaction, and allowed to cool to room temperature. A polymerized phenoxy resin layer) was formed.

By the above method, a plate-shaped aluminum member was produced in which a resin coating layer of an in-situ polymerizable phenoxy resin layer having a thickness of 90 μm was formed on the surface of the functional group-adhering layer of the aluminum plate.

(Joining process)
Next, the aluminum member is placed in an injection mold, and a plate made of polycarbonate resin (PC resin) ("LEXAN (registered trademark) 121R-111" manufactured by SABIC) is applied to the surface of the resin coating layer of the aluminum member. An injection molding machine ("SE100V" manufactured by Sumitomo Heavy Industries, Ltd.; cylinder temperature 300 ° C., tool temperature 110 ° C., injection speed 10 mm / sec, peak / holding pressure 100/80 [MPa / MPa]). The aluminum member and the resin member were joined by injection molding, thereby producing an aluminum-resin joined body.

<Comparative Test Example 4>
An aluminum member (without a resin coating layer) was prepared by sequentially performing the surface treatment step and the functional group-imparting layer forming step in the same manner as in Test Example 4. Then, on the surface of the functional group adhesion layer of the aluminum member, a plate-shaped resin member made of PC resin was injection-molded in the same manner as in Example 4 to try to join the aluminum member and the resin member. The member and the resin member were not joined at all.

<Test Example 5>
An aluminum plate was prepared by sequentially performing a surface treatment step and a functional group adhesion layer forming step in the same manner as in Test Example 4.

(Resin coating layer forming step)
Next, on the surface of the functional group adhesion layer of the aluminum plate, bisphenol A type epoxy resin (“jER (registered trademark) 828” manufactured by Mitsubishi Chemical Corporation) 100 g, pentaerythritol tetrakis (3-mercaptobutyrate) (Showa Denko K.K.) A curable resin composition obtained by dissolving 70 g of Karenz MT (registered trademark) PE1 (manufactured by the company; curing agent) and 10 g of 2,4,6-tris(dimethylaminomethyl)phenol in 344 g of acetone, after drying The coating was applied by a spray method so as to have a thickness of 5 μm. Then, the solvent was volatilized and cured by leaving it in the air at room temperature for 30 minutes to form a first resin coating layer (thermosetting resin layer).

Furthermore, on the surface of the thermosetting resin layer, an in-situ curable phenoxy resin layer having a thickness of 80 μm was formed by the same method as in Example 4 to form a second resin coating layer.

A plate having a resin coating layer consisting of two layers, a thermosetting resin layer with a thickness of 5 μm and an in-situ polymerizable phenoxy resin layer with a thickness of 80 μm, formed on the surface of the functional group-attached layer of the aluminum plate by the above method. A shaped aluminum member was produced.

(Joining process)
Next, on the surface of the resin coating layer (in-situ polymerization type phenoxy resin layer) of the aluminum member, a plate-shaped resin member made of PC resin was injection-molded in the same manner as in Experimental Example 4, thereby separating the aluminum member and the resin member. The aluminum-resin composite was produced by bonding.

<Comparative Test Example 5>
An aluminum plate was prepared by sequentially performing a surface treatment step and a functional group adhesion layer forming step in the same manner as in Test Example 4.

(Resin coating layer forming step)
Next, on the surface of the functional group adhesion layer of the aluminum plate, the first resin coating layer (thermosetting resin layer) was formed in the same manner as in Example 5, but on the surface of this thermosetting resin layer A second resin coating layer (that is, an in-situ polymerizable phenoxy resin layer) was not formed.

(Joining process)
Next, on the surface of the resin coating layer (thermosetting resin layer) of the aluminum member, a plate-shaped resin member made of PC resin was injection-molded in the same manner as in Example 4, thereby forming a bond between the aluminum member and the resin member. When an attempt was made to join, the aluminum member and the resin member were not joined at all.

[Evaluation of bonding properties]
The aluminum-resin joints produced in Examples 3 to 5 and Comparative Examples 3 to 5 were subjected to a tensile shear joint strength test under the same test conditions and method as above to measure the joint strength. These results are shown in Table 2. In addition, the meaning of the code|symbol in the "bonding-strength evaluation" column in Table 2 is the same as that of Table 1.

<Test Example 6>
The same aluminum plate as in Experimental Example 1 was prepared. Then, the aluminum plate was immersed in an aqueous sodium hydroxide solution with a concentration of 5% by mass for 1.5 minutes, neutralized with an aqueous nitric acid solution with a concentration of 5% by mass, washed with water, and dried to perform an etching treatment. .

Next, the aluminum plate after the etching treatment is boiled for 3 minutes in an aqueous solution containing 0.3% by mass of triethanolamine to perform a boehmite treatment. A boehmite film having

(Functional group adhesion layer forming step)
Next, 4 g of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Silicone Co., Ltd. "KBM-603"; silane coupling agent) was dissolved in 1000 g of industrial ethanol at 70°C. The boehmite-treated aluminum plate was immersed in the coupling agent-containing aqueous solution for 20 minutes. After that, the aluminum plate was taken out and dried to form a functional group adhering layer on the surface of the boehmite film (surface treatment portion).

(Resin coating layer forming step)
Next, an in situ polymerization type phenoxy resin composition obtained by dissolving 100 g of an epoxy resin ("jER (registered trademark) 828" manufactured by Mitsubishi Chemical Corporation), 61.6 g of bisphenol A, and 0.6 g of triethylamine in 300 g of acetone. was applied to the surface of the functional group-adhering layer of the aluminum plate by a spray method so that the thickness after drying was 3 μm. Then, after volatilizing the solvent by leaving it in the air at room temperature for 30 minutes, it is left in a furnace at 150 ° C. for 30 minutes to perform a polyaddition reaction, and allowed to cool to room temperature. A polymerized phenoxy resin layer) was formed.

By the above method, a plate-shaped aluminum member was produced in which a resin coating layer of a 3 μm-thick in-situ polymerizable phenoxy resin layer was formed on the surface of the functional group-adhering layer of the aluminum plate.

(Adhesive layer forming step and bonding step)
Next, on the surface of the resin coating layer of the aluminum member, a two-liquid type urethane adhesive was applied in a layer so that the thickness after drying was 2 μm. Then, the adhesive layer was cured by being left in the air at room temperature for 24 hours. In addition, as a two-component urethane adhesive, "Vinylol (registered trademark) OLY-5438-6" manufactured by Showa Denko K.K. An adhesive obtained by mixing 10 g of "Shokubaieki B" (trademark) was used.

(Joining process)
Next, the aluminum member is placed in a transfer molding die, and a plate-shaped resin member made of PBT-GF30 is formed on the surface of the adhesive layer of the aluminum member by a transfer molding method, whereby the aluminum member and the resin are formed. The members were bonded together to produce an aluminum-resin bonded body. PBT-GF30 is polybutylene terephthalate containing 30% glass fiber (that is, glass fiber reinforced polybutylene terephthalate).

<Comparative Test Example 6>
An aluminum member (without a resin coating layer) was prepared by sequentially performing a surface treatment step and a functional group adhesion layer forming step in the same manner as in Test Example 6. On the surface of the functional group adhesion layer of this aluminum member, a two-liquid type urethane-based adhesive was applied in layers in the same manner as in Example 6. Then, the adhesive layer was cured by being left in the air at room temperature for 24 hours. Next, the aluminum member and the resin member were joined in the same manner as in Example 6, thereby producing an aluminum-resin joined body.

[Evaluation of bonding properties]
The aluminum-resin joints produced in Example 6 of the above practical test and Example 6 of the comparative test were subjected to a tensile shear joint strength test under the same test conditions and method as above to measure the joint strength. These results are shown in Table 3. In addition, the meaning of the code|symbol in the "bonding-strength evaluation" column in Table 3 is the same as that of Table 1.

As can be seen from the evaluation results in Tables 1 to 3 above, all of the aluminum-resin bonded bodies of Examples 1 to 6 had high bonding strength.

Also, as the aluminum base material, an aluminum plate made of another aluminum material was molded by hot die forging, and then the surface of the aluminum plate was smoothed by machining. The aluminum material of the aluminum plate is Si: 0.6% by mass, Fe: 0.25% by mass, Cu: 0.3% by mass, Mg: 1.0% by mass, and the balance is Al and unavoidable impurities. have.

Next, the aluminum plate and the resin member were bonded in the same manner as in Examples 1 to 6, thereby producing an aluminum-resin bonded body. Then, these bonded bodies were subjected to a tensile shear bonding strength test under the same test conditions and method as above to measure the bonding strength. As a result, all of these bonded bodies had high bonding strength.

Therefore, according to the present invention, it is considered possible to manufacture a back door in which an aluminum member and a resin member are firmly joined.

INDUSTRIAL APPLICABILITY The present invention is applicable, for example, to a back door for a hatchback type automobile and a manufacturing method thereof.

1: Aluminum member 2: Aluminum substrate 2a: Surface treatment layer 3: Functional group adhesion layer 4: Resin coating layer 5: Primer layer 7: Adhesive layer 8: Resin member 8A: First resin member 8B: Second resin member 10: Back door 11: Frame 21: Inner panel 22: Outer panel

Claims (8)

An aluminum member in which a plurality of resin coating layers are laminated on at least a part of the surface of an aluminum base material, and a resin member bonded to the surface of the aluminum base material on the resin coating layer side of the aluminum member. ,
The resin coating layer is laminated on the surface-treated surface of the aluminum base,
At least one layer of the resin coating layer is an automotive back door formed from a resin composition containing an in-situ polymerizable phenoxy resin,
At least one layer other than the layer formed from the resin composition containing the in-situ polymerizable phenoxy resin in the resin coating layer is formed from a resin composition containing a thermosetting resin,
The in-situ polymerizable phenoxy resin has a thermoplastic structure formed by a polyaddition reaction of a bifunctional epoxy resin and a bifunctional phenol compound in the presence of a catalyst,
The automotive back door, wherein the thermosetting resin is at least one selected from the group consisting of urethane resins , vinyl ester resins and unsaturated polyester resins. Having a functional group attachment layer between the surface-treated surface of the aluminum substrate and the resin coating layer,
2. The automotive back door according to claim 1, wherein said functional group-adhering layer has a functional group introduced from at least one selected from the group consisting of silane coupling agents, isocyanate compounds and thiol compounds. 3. The back door for automobiles according to claim 1, wherein said surface treatment is at least one selected from the group consisting of blasting, polishing, etching and chemical conversion. The automotive back door according to any one of claims 1 to 3, wherein the resin coating layer is a primer layer. The automobile according to any one of claims 1 to 4, wherein the aluminum base material is made of an extruded aluminum profile of an A6000 series alloy, and has properties such as a tensile strength of 240 MPa or more and a Young's modulus of 65 GPa or more. back door. The automobile back according to any one of claims 1 to 4, wherein the aluminum base material is made of an aluminum forged material of an A4000 series alloy, and has properties such as a tensile strength of 350 MPa or more and a Young's modulus of 70 GPa or more. door. A resin inner panel arranged inside the vehicle body interior, a resin outer panel arranged outside the vehicle body, and an aluminum frame arranged between the two panels,
The frame is the aluminum member,
Each panel is the resin member,
At least a contact surface of the frame with each panel is a surface on the resin coating layer side,
7. The automotive back door according to any one of claims 1 to 6, wherein each panel is joined to the contact surface of the frame. A method for manufacturing an automobile back door according to any one of claims 1 to 7,
When molding a resin member by injection molding, transfer molding, press molding, filament winding molding, or hand lay-up molding, the resin member is joined to the resin coating layer side of the aluminum substrate of the aluminum member. A method for manufacturing an automobile back door.

Images