JP7600769B2 - Vehicle-mounted camera and its manufacturing method - Google Patents

Description

This disclosure relates to an on-board camera that is attached to the windshield of an automobile and a method for manufacturing the same.

Conventionally, vehicle-mounted cameras incorporating various modules are known, and highly reliable vehicle-mounted cameras are known in which the operation of the camera body is not affected even if the camera body heats up due to heat generated by these modules.

Patent document 1 (JP 2017-118445 A) discloses an in-vehicle camera in which a connection board has an upper part located above the main board and connected to the camera board, a lower part located below the main board and connected to the underside of the main board, and a bent part located between the upper and lower parts and intersecting with the outer periphery of the main board, and the upper part is connected to the camera board at its front end.

JP 2017-118445 A

However, the modules built into vehicle-mounted cameras contain a wide variety of precision instruments, and because these instruments are highly vulnerable to water vapor, dirt, and dust, the housing that covers the modules must be airtight.

In addition, in recent years, there has been a trend toward an increasing number and variety of modules incorporated into vehicle-mounted cameras, which has resulted in the camera body heating up more and more, creating a demand for vehicle-mounted cameras with high heat dissipation capabilities.

The objective of the present disclosure is to provide an in-vehicle camera that can achieve excellent airtightness and excellent heat dissipation, and a method for inexpensively manufacturing such an in-vehicle camera.

The present invention is based on the discovery that by providing a resin coating layer (primer layer) made of a specific material on the surface of a metal component, the bonding strength between the metal component and the resin component can be increased even when exposed to high temperatures exceeding 100°C.

This disclosure encompasses the following aspects:

[1] An in-vehicle camera comprising a metal member, a resin member, and one or more resin coating layers laminated on at least one of the metal member and the resin member,
the metal member is a first housing part,
the resin member is a second housing part,
the metal member and the resin member are joined via the resin coating layer,
at least one of the resin coating layers is formed from a cured product of an epoxy resin composition containing a composition (A) including a difunctional epoxy resin and a dihydric phenol compound, and a composition (B);
The composition (B) includes at least one combination selected from the following (B1) to (B3):
The surface of the metal member opposite to the surface on which the resin coating layer is laminated has an uneven shape.
(B1) A combination of an epoxy resin having a fluorene skeleton and a phenol compound having one or more selected from a fluorene skeleton, an imidazolidinone skeleton, and an aminotriazine skeleton. (B2) A combination of an epoxy resin having a biphenyl skeleton and a phenol compound having one or more selected from a fluorene skeleton, an imidazolidinone skeleton, and an aminotriazine skeleton. (B3) A combination of an allylphenol compound and a bismaleimide compound. [2] The vehicle-mounted camera according to the above [1], wherein the content of the composition (B) in the epoxy resin composition is 10 to 80 parts by mass relative to 100 parts by mass of the total content of the composition (A) and the composition (B).
[3] The vehicle-mounted camera according to [1] or [2] above, wherein the surface of the metal member has a surface that has been surface-treated with one or more treatments selected from a blasting treatment, a polishing treatment, an etching treatment, and a chemical conversion treatment.
[4] A functional group-containing layer is provided between the metal member and the resin coating layer and is laminated in contact with the metal member and the resin coating layer,
The vehicle-mounted camera according to any one of the above [1] to [3], wherein the functional group-containing layer has a structure derived from one or more functional groups selected from the following (C1) to (C7).
(C1) one or more functional groups selected from an amino group, a mercapto group, a (meth)acryloyl group, an epoxy group, and an isocyanato group derived from a silane coupling agent; (C2) a functional group generated by reacting an amino group derived from a silane coupling agent with an epoxy compound; (C3) a functional group generated by reacting a mercapto group derived from a silane coupling agent with one or more compounds selected from an epoxy compound, an isocyanate compound, an epoxy-modified (meth)acrylate compound, and an amino group-containing (meth)acrylate compound; (C4) a functional group generated by reacting a (meth)acryloyl group derived from a silane coupling agent with a thiol compound; (C5) a functional group generated by reacting an epoxy group derived from a silane coupling agent with one or more compounds selected from an amino compound, a thiol compound, and an amino group-containing (meth)acrylate compound; (C6) an isocyanato group derived from an isocyanate compound; (C7) a mercapto group derived from a thiol compound [5] The resin coating layer is a plurality of layers, and further includes a resin coating layer formed from a cured product of a curable resin,
The vehicle-mounted camera according to any one of the above [1] to [4], wherein the curable resin is one or more selected from an allyl-modified maleimide resin, a urethane resin, an epoxy resin, a vinyl ester resin, and an unsaturated polyester resin.
[6] The vehicle-mounted camera according to any one of [1] to [5] above, wherein the metal member includes an aluminum material, and the thermal conductivity of the aluminum material is 150 W/(m·K) or more.
[7] The vehicle-mounted camera according to any one of [1] to [6], wherein the metal member includes an aluminum extrusion material, and the aluminum extrusion material has a thermal conductivity of 180 W / (m · K) or more and a tensile strength of 150 MPa or more.
[8] The vehicle-mounted camera according to any one of [1] to [6], wherein the metal member includes an aluminum forging, and the aluminum forging has a thermal conductivity of 180 W / (m · K) or more and a tensile strength of 150 MPa or more.
[9] A method for manufacturing an in-vehicle camera according to any one of the above [1] to [8], comprising heating the resin coating layer and bonding the metal member and the resin member by pressing the metal member and the resin member together so that the heated resin coating layer is interposed between the metal member and the resin member.

The present disclosure makes it possible to provide an in-vehicle camera that can achieve excellent airtightness and excellent heat dissipation, and such an in-vehicle camera can be manufactured inexpensively.

FIG. 1 is a side view of a vehicle showing the position of an on-board camera (dotted line portion) in the vehicle. FIG. 2 is a perspective view showing the vehicle-mounted camera shown in FIG. FIG. 3 is a cross-sectional view taken along line AA' in FIG. FIG. 4 is a schematic cross-sectional view showing a state in which one resin coating layer is laminated on a metal member in a resin coating layer laminate of one embodiment. FIG. 5 is a schematic cross-sectional view showing a state in which a plurality of resin coating layers are laminated on a metal member in a resin coating layer laminate according to another embodiment. FIG. 6 is a schematic cross-sectional view of the resin coating layer laminate and the resin member bonded together.

Next, an embodiment of the present disclosure will be described below with reference to the drawings.

In this disclosure, unless otherwise specified in the text, the term "metal" is used to include both pure metals consisting of a single metallic element and alloys in which a pure metal is mixed with one or more other elements. For example, the term "aluminum" includes pure aluminum metal and its alloys.

In this disclosure, bonding means joining two objects together, with adhesion and welding being subordinate concepts. Adhesion means joining two adherends (things to be bonded) together using an organic material such as tape or adhesive (curable resin, thermoplastic resin, etc.). Welding means melting the surface of the adherend, such as thermoplastic resin, with heat, and joining the two together through molecular diffusion-induced entanglement and crystallization by contact pressure and cooling.

In this disclosure, "(meth)acryloyl" means acryloyl or methacryloyl. Similarly, "(meth)acrylic" means acrylic or methacrylic, and "(meth)acrylate" means acrylate or methacrylate.

In this disclosure, "room temperature" means typical room temperature within the range of 25±5°C.

[In-vehicle camera]
1 is a side view of a vehicle showing the position of an on-vehicle camera 10 (indicated by a dotted line) in the vehicle. As shown in the figure, the on-vehicle camera 10 is attached to both the front windshield and the rear windshield via brackets 11.

2 is a perspective view showing the vehicle-mounted camera 10 shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line A-A' in FIG. 2. As shown in FIG. 3, the vehicle-mounted camera 10 has a structure in which a connector 16, an electronic board 18, a module 20, and a thermally conductive sheet 22 are incorporated within an area surrounded by a first housing part 12 and a second housing part 14. The thermally conductive sheet 22 is not particularly limited as long as it is used for heat dissipation of semiconductors, and examples of the thermally conductive sheet 22 include a thermoplastic resin sheet, an elastomer sheet, a cured resin sheet, or an adhesive sheet in which a thermally conductive filler such as silica, alumina, boron nitride, aluminum nitride, silicon carbide, boron carbide, boron carbon nitride, graphite, carbon fiber, carbon nanotube, or alumina is dispersed in a binder such as silicone, acrylic resin, or epoxy resin.

The first housing part 12 is joined to the second housing part 14 on the vertical upper surface in Figs. 2 and 3. A heat sink area 12a having a vertically uneven shape is formed on the surface of the first housing part 12 opposite to the surface joined to the second housing part 14. The heat sink area 12a is an area that enhances heat dissipation by having a vertically uneven shape and securing a large surface area. In Fig. 3, the ratio of the surface area of the convex portion to the surface area of the first housing part when there is no convex portion (heat sink area 12a) can be 1% to 200%, and in such a case, the surface area of the heat sink area 12a can be efficiently increased to achieve particularly excellent heat dissipation.

Connectors 16 are connected to the two corners of the second part 14, and an electronic board 18 is fixed by these connectors 16. A module 20, such as a microcomputer, is connected to the vertically lower side of the electronic board 18, and a thermally conductive sheet 22 is interposed between the module 20 and the first housing part 12. The microcomputer here includes a unit that performs calculations necessary for autonomous driving using image data captured by a camera body (not shown).

In an in-vehicle camera 10 configured in this manner, heat generated in the module 20 can be dissipated through the thermally conductive sheet 22 to the first housing part 12, which is made of aluminum, for example, and can then be efficiently dissipated to the outside in the heat sink area 12a of the first housing part 12.

The first housing part 12 and the second housing part 14 are joined via a resin coating layer described below. The resin coating layer may be laminated on the first housing part 12, may be laminated on the second housing part 14, or may be laminated on both the first housing part 12 and the second housing part 14. Hereinafter, the first housing part 12 is also referred to as the "metal member 2," and the second housing part 14 is also referred to as the "resin member 5."

[Resin coating layer laminate 1]
In one embodiment, one or more resin coating layers are laminated on a metal member 2 to form a resin coating layer laminate 1. Fig. 4 shows a schematic cross-sectional view of the resin coating layer laminate 1 of one embodiment. The resin coating layer laminate 1 shown in Fig. 4 includes a metal member 2 and one or more resin coating layers 3 laminated on the metal member 2. At least one layer of the resin coating layer 3 is formed from a cured product of an epoxy resin composition containing a composition (A) containing a difunctional epoxy resin and a dihydric phenol compound, and a composition (B). The composition (B) is characterized by including at least one combination selected from the following (B1) to (B3).
(B1) A combination of an epoxy resin having a fluorene skeleton and a phenol compound having one or more skeletons selected from a fluorene skeleton, an imidazolidinone skeleton, and an aminotriazine skeleton. (B2) A combination of an epoxy resin having a biphenyl skeleton and a phenol compound having one or more skeletons selected from a fluorene skeleton, an imidazolidinone skeleton, and an aminotriazine skeleton. (B3) A combination of an allylphenol compound and a bismaleimide compound.

When the resin coating layer 3 of the resin coating layer laminate 1 is bonded to the resin member 5, it can maintain a high bonding strength between the metal member 2 and the resin member 5 even when exposed to high temperatures exceeding 100°C.

<Metal member 2>
The metal type of the metal member 2 is not particularly limited. Examples of metal types include aluminum, iron, titanium, magnesium, stainless steel, and copper. These metal types may be pure metals or alloys. Among these, aluminum is preferably used from the viewpoints of heat dissipation characteristics, light weight, and ease of processing. The application of aluminum will be described in detail below.

When aluminum is used for the metal member 2, the type of aluminum material for the metal member 2 is not limited, and examples include aluminum materials with an aluminum content of 50 mass% or more. The aluminum material is preferably an A1000 series alloy, an A6000 series alloy (e.g., A6061, A6063, A6082, A6110), an A4000 series alloy, etc. It is more preferable that the aluminum material is an A6063 aluminum alloy, which has high thermal conductivity and high strength.

The thermal conductivity of the aluminum material is preferably 150 W/(m·K) or more, and more preferably 180 W/(m·K) or more.

The metal member 2 preferably includes an aluminum extrusion or an aluminum forging. The aluminum extrusion preferably has a thermal conductivity of 180 W/(m·K) or more and a tensile strength of 150 MPa or more. The aluminum forging preferably has a thermal conductivity of 180 W/(m·K) or more and a tensile strength of 150 MPa or more. In these cases, since the metal member 2 has a high thermal conductivity (high thermal conductivity) and a high tensile strength (high strength), the strength of the metal member 2 can be increased, and the heat dissipation characteristics of the metal member 2 can be improved. The upper limit of the tensile strength is not limited, and is, for example, 450 MPa. The upper limit of the thermal conductivity is not limited, and is, for example, 250 W/(m·K). In this disclosure, the thermal conductivity and tensile strength are values at room temperature.

When the metal member 2 includes an aluminum extrusion material, the metal member 2 is preferably manufactured by the following method. Specifically, the steps of continuously casting a cast rod by supplying a molten aluminum material having a predetermined characteristic to a continuous casting device, homogenizing the cast rod, cutting the cast rod to a predetermined length to obtain a billet as an extrusion processing material, grinding the outer diameter of the billet, and hot extruding the billet to form an extrusion material with a predetermined cross-sectional shape are performed in this order. Next, the extrusion material is cut to a predetermined length, and predetermined processing such as grinding and deburring is performed on both cut end faces to obtain the metal member 2 including the aluminum extrusion material. When a high-strength alloy such as an A6000 series alloy or an A4000 series alloy is used as the metal member 2, it is preferable to apply high strength by T6 heat treatment (a combination of water-cooled quenching from solution treatment and age hardening treatment (tempering)) before processing the extrusion material.

When the metal member 2 includes an aluminum forging, the metal member 2 is preferably manufactured by the following method. Specifically, the steps of continuously casting a cast rod by supplying a molten aluminum material having a predetermined characteristic to a continuous casting device, obtaining a billet (raw material) by cutting the cast rod to a predetermined length, homogenizing the billet, surface-cutting the outer diameter of the billet, and hot die forging the billet to form a base material having a heat sink fin on a base plate as a forging material are performed in this order. When a high-strength alloy such as an A6000 series alloy or an A4000 series alloy is used as the metal member 2, a T6 heat treatment (a combination of water-cooled quenching from a solution treatment and age hardening treatment (tempering)) is subsequently performed. Next, welding grooves are machined (e.g., cutting) at predetermined locations (both ends, etc.) of the base material, and finishing is performed at predetermined locations (such as the surface to be joined with the resin member 5) of the base material by machining (e.g., cutting). A plurality of such preforms are produced and then joined by MIG welding, friction stir welding, etc. In this way, the metal member 2 including the aluminum forging is obtained. A plurality of such preforms may be produced and then joined by MIG welding, friction stir welding, etc.

<Resin coating layer 3>
In one embodiment, the resin coating layer 3 is laminated on the metal member 2. The resin coating layer 3 may be composed of one layer or multiple layers.

The resin coating layer 3 formed on the surface of the metal member 2 allows it to be bonded to the resin member 5 with high bonding strength. The resin coating layer 3 is also firmly adhered to the surface of the metal member 2, and can protect the surface of the metal member 2 from dirt, oxidation, and other deterioration.

At least one of the resin coating layers 3 is a layer (hereinafter also referred to as an "epoxy resin layer") formed from a cured product of an epoxy resin composition containing a composition (A) containing a bifunctional epoxy resin and a dihydric phenol compound, and a composition (B) shown below.

By curing the epoxy resin composition by in-situ polymerization, it is possible to form a resin coating layer 3 that has excellent adhesion to the metal member 2 and provides high bonding strength with the resin member 5 even when exposed to high temperatures exceeding 100°C.

Composition (A) is a resin composition that forms a so-called in-situ polymerized thermoplastic epoxy resin. The epoxy resin layer is formed by the reaction of an epoxy resin composition containing composition (A) and composition (B), and has a linear polymer structure, or a linear polymer structure in which a crosslinked structure is formed in part to the extent that the molecular miscibility with the thermoplastic resin is not impaired. Therefore, unlike curable resins that are entirely composed of a three-dimensional network with a crosslinked structure, the epoxy resin layer can form a resin coating layer 3 that has excellent molecular miscibility with the thermoplastic resin.

The epoxy resin layer may be formed in one layer or in two or more layers. When there are two or more layers, each epoxy resin layer may be formed from the same cured product of the epoxy resin composition, or may be formed from the cured products of different epoxy resin compositions.

The epoxy resin composition that forms the epoxy resin layer is composed of multiple compounds, and it is common technical knowledge for those skilled in the art that multiple functional groups can be involved and cause various complex reactions depending on the compounding ratio of these multiple compounds, reaction conditions, etc. For this reason, it is considered impossible or impractical to directly identify and comprehensively express the specific chemical structure or characteristics of the epoxy resin layer. Therefore, in the present disclosure, the epoxy resin layer is specified by the composition raw material that forms the epoxy resin layer, i.e., the composition of the epoxy resin composition.

In this disclosure, an epoxy resin composition "contains" composition (A) and composition (B) means that composition (A) and composition (B) are blended as composition raw materials for the epoxy resin composition. A composition that can fall into either composition (A) or composition (B) is considered to be composition (B).

(Composition (A))
The composition (A) contains a difunctional epoxy resin and a dihydric phenol compound.

Examples of bifunctional epoxy resins include bisphenol type epoxy resins "jER (registered trademark) 828", "jER (registered trademark) 834", "jER (registered trademark) 1001", "jER (registered trademark) 1004", and "jER (registered trademark) 1007"; and biphenyl type epoxy resin "jER (registered trademark) YX4000" (all manufactured by Mitsubishi Chemical Corporation). These bifunctional epoxy resins may be used alone or in combination of two or more types.

Examples of dihydric phenol compounds include bisphenol compounds such as bisphenol A, bisphenol F, and bisphenol S, and biphenol compounds such as 4,4'-biphenol. These dihydric phenol compounds may be used alone or in combination of two or more.

Examples of combinations of bifunctional epoxy resins and dihydric phenol compounds in composition (A) include bisphenol A type epoxy resin and bisphenol A, bisphenol A type epoxy resin and bisphenol F, bisphenol A type epoxy resin and bisphenol S, and biphenyl type epoxy resin and 4,4'-biphenol. Another example is the combined use of "EX-991L" and "WPE190" manufactured by Nagase ChemteX Corporation.

The blend ratio of the bifunctional epoxy resin and the bivalent phenol compound in composition (A) is preferably set so that the molar equivalent ratio of epoxy groups to hydroxyl groups is 0.7 to 1.5, taking into consideration the reactivity of both. The molar equivalent ratio of epoxy groups to hydroxyl groups is more preferably 0.8 to 1.4, and even more preferably 0.9 to 1.3.

(Composition (B))
The composition (B) includes at least one combination selected from the following (B1) to (B3).
(B1) A combination of an epoxy resin having a fluorene skeleton and a phenol compound having one or more skeletons selected from a fluorene skeleton, an imidazolidinone skeleton, and an aminotriazine skeleton. (B2) A combination of an epoxy resin having a biphenyl skeleton and a phenol compound having one or more skeletons selected from a fluorene skeleton, an imidazolidinone skeleton, and an aminotriazine skeleton. (B3) A combination of an allylphenol compound and a bismaleimide compound.

(B1) and (B2) are a combination that constitutes an epoxy resin composition different from composition (A), and (B3) is a combination that forms an allyl-modified maleimide resin.

By using at least one of (B1) to (B3) in combination with composition (A) to form an epoxy resin composition, it is possible to form a resin coating layer 3 that exhibits high bonding strength with the resin member 5 even when exposed to high temperatures exceeding 100°C. In other words, (B1) to (B3) are components that improve the heat resistance of the epoxy resin.

The blend ratio of the epoxy resin and the phenolic compound in (B1) is preferably set so that the molar equivalent ratio of epoxy groups to hydroxyl groups is 0.7 to 1.5, taking into consideration the reactivity of the two. The molar equivalent ratio of epoxy groups to hydroxyl groups is more preferably 0.8 to 1.4, and even more preferably 0.9 to 1.3.

The ratio of the epoxy resin to the phenolic compound in (B2) is the same as that in (B1) above.

The blending ratio of the allylphenol compound and the bismaleimide compound in (B3) is preferably set so that the molar equivalent ratio of maleimide groups to allyl groups is 0.7 to 1.5. The molar equivalent ratio of maleimide groups to allyl groups is more preferably 0.8 to 1.4, and even more preferably 0.9 to 1.3.

The content of composition (B) in the epoxy resin composition is preferably 10 to 80 parts by mass, more preferably 10 to 70 parts by mass, and even more preferably 20 to 65 parts by mass, per 100 parts by mass of the total content of composition (A) and composition (B).

By including composition (B) in the epoxy resin composition at a content within the above range, it is possible to form a resin coating layer 3 that has good heat resistance while maintaining molecular compatibility with the thermoplastic resin.

In this disclosure, the content of composition (A) and/or composition (B) refers to the blended amount of composition (A) and/or composition (B), and does not include the amount of the solvent described below.

From the viewpoint of forming an epoxy resin layer having molecular compatibility with thermoplastic resins and heat resistance, the total content of composition (A) and composition (B) in 100% by mass of the epoxy resin composition (excluding the solvent) is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, and even more preferably 80 to 100% by mass.

The epoxy resin having a fluorene structure in (B1) is preferably a bifunctional epoxy resin. Examples of epoxy resins having a fluorene structure include "OGSOL (registered trademark) PG-100", "OGSOL (registered trademark) CG-500", "OGSOL (registered trademark) EG-200", and "OGSOL (registered trademark) EG-280" (all manufactured by Osaka Gas Chemicals Co., Ltd.). These epoxy resins having a fluorene structure may be used alone or in combination of two or more types.

The phenolic compounds having a fluorene structure in (B1) and (B2) are preferably divalent phenolic compounds. Examples of phenolic compounds having a fluorene structure include "BPF" (bisphenol fluorene; 9,9-bis(4-hydroxyphenyl)fluorene), "BPEF" (bisphenoxyethanol fluorene; 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene), and "BCF" (biscresol fluorene); 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (all manufactured by Osaka Gas Chemicals Co., Ltd.). These phenolic compounds having a fluorene structure may be used alone or in combination of two or more kinds.

An example of the phenolic compounds having an imidazolidinone skeleton in (B1) and (B2) is "TAM-005" (manufactured by Aica Kogyo Co., Ltd.), which is derived from a novolac-type phenolic resin. These phenolic compounds having an imidazolidinone skeleton may be used alone or in combination of two or more kinds.

Examples of the phenolic compounds having an aminotriazine skeleton in (B1) and (B2) include novolak-type phenolic resins modified with melamine, benzoguanamine, etc., such as "Phenolite (registered trademark) LA-7052", "Phenolite (registered trademark) LA-7054", "Phenolite (registered trademark) LA-7751", "Phenolite (registered trademark) LA-1356", and "Phenolite (registered trademark) LA-3018-50P" (all manufactured by DIC Corporation). These phenolic compounds having an aminotriazine skeleton may be used alone or in combination of two or more kinds.

Examples of the epoxy resin having a biphenyl skeleton in (B2) include "jER (registered trademark) YX-4000", "jER (registered trademark) YX-4000H", "jER (registered trademark) YL6121HA", and "jER (registered trademark) YL6677" (all manufactured by Mitsubishi Chemical Corporation), as well as "NC-3000", "NC-3000-L", "NC-3000-H", "NC-3000-FH-75M", "NC-3100", and "CER-3000-L" (all manufactured by Nippon Kayaku Co., Ltd.). These epoxy resins having a biphenyl skeleton may be used alone or in combination of two or more kinds.

Examples of the allylphenol compound in (B3) include "APG low viscosity allylphenol resin", "LVA low volatility allylphenol resin", "FTC-AE low polarity allyl ether phenol resin", and "FATC low polarity multifunctional allylphenol resin" (all manufactured by Gun-ei Chemical Industry Co., Ltd.) derived from novolac type phenol resin. These allylphenol compounds may be used alone or in combination of two or more kinds.

Examples of the bismaleimide compounds in (B3) include 4,4'-diphenylmethane bismaleimide "BMI-1000", "BMI-1000H", "BMI-1100", and "BMI-1100H"; m-phenylene bismaleimide "BMI-3000" and "BMI-3000H"; bisphenol A diphenyl ether bismaleimide "BMI-4000"; 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide "BMI-5000"; and 1,6'-bismaleimide-(2,2,4-trimethyl)hexane "BMI-TMH" (all manufactured by Daiwa Chemical Industry Co., Ltd.). These bismaleimide compounds may be used alone or in combination of two or more.

A catalyst may be added to the epoxy resin composition to promote the polyaddition reaction. Examples of suitable catalysts include tertiary amines such as triethylamine and 2,4,6-tris(dimethylaminomethyl)phenol; and phosphorus compounds such as triphenylphosphine.

The catalyst may be contained in either composition (A) or composition (B), or in both composition (A) and composition (B).

When a catalyst is added, the amount of the catalyst used is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, and even more preferably 0.1 to 2 parts by mass, per 100 parts by mass of the total raw material compounds that form the epoxy resin, from the viewpoint of appropriately promoting the polyaddition reaction.

Composition (A) and/or composition (B) may contain a solvent from the viewpoints of ease of mixing these compositions and ease of coating the epoxy resin composition. As the solvent, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, tetrahydrofuran, cyclohexane, n-hexane, ethanol, and methanol are preferably used from the viewpoints of solubility of composition (A) and/or composition (B) and suppression of residues after the polyaddition reaction of the epoxy resin composition.

Composition (A) and/or composition (B) may contain additives such as colorants as necessary to form the desired resin coating layer 3. In this case, the total amount of raw material compounds forming the epoxy resin is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more, based on 100% by mass of the epoxy resin composition (excluding the solvent).

The resin coating layer laminate 1 is preferably manufactured by reacting an epoxy resin composition containing composition (A) and composition (B) on the surface of the metal member 2 to form one or more layers of the resin coating layer 3.

By forming an epoxy resin layer by reacting an epoxy resin composition on the surface of the metal member 2, a resin coating layer laminate 1 can be obtained in which the resin coating layer 3 is firmly adhered to the surface of the metal member 2.

The method for coating the surface of the metal member 2 with the epoxy resin composition is not particularly limited, but examples include a spray coating method and a dipping method.

The heating temperature when reacting the coated epoxy resin composition to form an epoxy resin layer depends on the type of compound to be reacted, but from the viewpoints of ease of operation in on-site polymerization and production efficiency of the resin coating layer laminate 1, it is preferably 120 to 200°C, more preferably 120 to 180°C, and even more preferably 130 to 170°C. From the same viewpoint, the heating time is preferably 5 to 90 minutes, more preferably 10 to 80 minutes, and even more preferably 15 to 60 minutes.

When the epoxy resin composition contains a solvent, it is preferable to coat the epoxy resin composition, then dry it as appropriate to volatilize the solvent, and then heat it to cause the reaction.

(Curable Resin Layer)
When the resin coating layer 3 is composed of a plurality of layers, it may further include, in addition to the epoxy resin layer, a resin coating layer formed from a cured product of a resin composition containing a curable resin (hereinafter, also referred to as a "curable resin layer") Examples of the curable resin include allyl-modified maleimide resin, urethane resin, epoxy resin, vinyl ester resin, and unsaturated polyester resin.

The curable resin layer may be formed from one of these resins, or from a mixture of two or more of them. The curable resin layer may be composed of two or more layers, and each layer may be formed from a resin composition containing a different type of curable resin.

The resin coating layer 3 has a laminated structure of an epoxy resin layer and a curable resin layer, so that the resin coating layer 3 can be endowed with various properties such as strength and impact resistance based on the curable resin.

The order in which the curable resin layer and the epoxy resin layer are stacked is not particularly limited, but from the viewpoint of bonding the metal member 2 and the resin member 5 with high bonding strength, it is preferable to stack them so that the outermost surface of the resin coating layer 3 is the epoxy resin layer.

The method for coating the resin composition containing the curable resin is not particularly limited, but examples include spray coating and dipping.

The resin composition may contain a solvent from the viewpoint of ease of mixing and coating. The resin composition may contain additives such as colorants as necessary to form the desired resin coating layer 3. In this case, the total of the raw material compounds forming the curable resin is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more in 100% by mass of the resin composition (excluding the solvent).

In this disclosure, a curable resin means a resin that cures by crosslinking, and is not limited to heat-curing types, but also includes room temperature curing types and light-curing types. Light-curing types can be cured in a short time by irradiation with visible light or ultraviolet light. Light-curing types may be used in combination with heat-curing types and/or room temperature curing types. Examples of light-curing types include vinyl ester resins such as "Lipoxy (registered trademark) LC-760" and "Lipoxy (registered trademark) LC-720" (both manufactured by Showa Denko KK).

[Allyl-modified maleimide resin]
The allyl-modified maleimide resin is a reaction product obtained by combining an allyl compound with a bismaleimide compound. Allyl-modified maleimide resins are known as highly heat-resistant resins, and some have a glass transition temperature of 250° C. or higher. For this reason, the use of allyl-modified maleimide resins is effective in increasing the heat resistance of the resin coating layer 3.

The allyl compound may be, for example, the same as the allylphenol compound in (B3) described above. The bismaleimide compound may be, for example, the same as the bismaleimide compound in (B3) described above. A curable resin layer can be formed by curing a composition containing a combination of these allyl compounds and bismaleimide compounds, for example, using a peroxide catalyst.

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

Examples of one-component urethane resins include oil-modified types (cured by oxidative polymerization of unsaturated fatty acid groups), moisture-cured types (cured by reaction of isocyanato groups with water in the air), block types (cured by reaction of hydroxyl groups with isocyanato groups regenerated by dissociation of the blocking agent by heating), and lacquer types (cured by evaporation of the solvent and drying). Among these, moisture-cured one-component urethane resins are preferably used from the viewpoint of ease of handling. Specific examples of moisture-cured one-component urethane resins include "UM-50P" (manufactured by Showa Denko KK).

Two-component urethane resins include, for example, catalyst-curing types (which cure when isocyanato groups react with water in the air in the presence of a catalyst) and polyol-curing types (which cure when isocyanato groups react with hydroxyl groups of a polyol compound).

Examples of polyol compounds in polyol curing types include polyester polyols, polyether polyols, and phenolic resins.

Examples of isocyanate compounds having an isocyanato group in the polyol curing type include aliphatic isocyanates such as hexamethylene diisocyanate (HDI), tetramethylene diisocyanate, and dimer acid diisocyanate; aromatic isocyanates such as 2,4- or 2,6-tolylene diisocyanate (TDI) or mixtures thereof, p-phenylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate (MDI) or its polynuclear mixture, polymeric MDI; and alicyclic isocyanates such as isophorone diisocyanate (IPDI).

The blend ratio of the polyol compound to the isocyanate compound in the polyol-curing type two-component urethane resin is preferably set so that the molar equivalent ratio of hydroxyl groups to isocyanato groups is 0.7 to 1.5.

Examples of urethane catalysts used in two-component urethane resins include amine catalysts such as triethylenediamine, tetramethylguanidine, N,N,N',N'-tetramethylhexane-1,6-diamine, dimethyletheramine, N,N,N',N",N"-pentamethyldipropylene-triamine, N-methylmorpholine, bis(2-dimethylaminoethyl)ether, dimethylaminoethoxyethanol, and triethylamine; and organotin catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dibutyltin thiocarboxylate, and dibutyltin dimaleate.

In the case of polyol curing type, it is generally preferable to mix 0.01 to 10 parts by mass of urethane catalyst per 100 parts by mass of polyol compound.

[Epoxy resin]
Epoxy resin is a resin having two or more epoxy groups in one molecule. Examples of prepolymers of epoxy resin before curing include ether-based bisphenol-type epoxy resins, novolac-type epoxy resins, polyphenol-type epoxy resins, aliphatic-type epoxy resins, ester-based aromatic epoxy resins, cyclic aliphatic epoxy resins, and ether-ester-based epoxy resins. Among these, bisphenol A-type epoxy resins are preferably used. These epoxy resins may be used alone or in combination of two or more.

Examples of bisphenol A type epoxy resins include "jER (registered trademark) 828" and "jER (registered trademark) 1001" (both manufactured by Mitsubishi Chemical Corporation).

An example of a novolac type epoxy resin is "D.E.N. (registered trademark) 438 (registered trademark)" (manufactured by The Dow Chemical Company).

Examples of hardeners used for epoxy resins include known hardeners such as aliphatic amines, aromatic amines, acid anhydrides, phenolic resins, thiols, imidazoles, and cationic catalysts. By using a hardener in combination with a long-chain aliphatic amine and/or thiols, a resin coating layer 3 with high elongation and excellent impact resistance can be formed.

Thiols in the curing agent include the same compounds as those exemplified as the thiol compounds used in forming the functional group-containing layer described below. Among these, pentaerythritol tetrakis (3-mercaptobutyrate) "Karenz MT (registered trademark) PE1" (manufactured by Showa Denko K.K.) is preferred from the viewpoint of the elongation rate and impact resistance of the resin coating layer 3.

[Vinyl ester resin]
Vinyl ester resins are prepared by dissolving a vinyl ester compound in a polymerizable monomer such as styrene. Vinyl ester resins are also called epoxy (meth)acrylate resins, but in the present disclosure, vinyl ester resins also include urethane (meth)acrylate resins.

As vinyl ester resins, for example, those described in "Polyester Resin Handbook" (published by Nikkan Kogyo Shimbun, 1988) and "Paint Terminology Dictionary" (published by the Color Materials Association, 1993) can be used. Specific examples of vinyl ester resins include "Lipoxy (registered trademark) R-802", "Lipoxy (registered trademark) R-804", and "Lipoxy (registered trademark) R-806" (all manufactured by Showa Denko KK).

An example of the urethane (meth)acrylate resin is a radical polymerizable unsaturated group-containing oligomer obtained by reacting an isocyanate compound with a polyol compound, followed by a reaction with a hydroxyl group-containing (meth)acrylic monomer and, if necessary, a hydroxyl group-containing allyl ether monomer. A specific example of the urethane (meth)acrylate resin is "Lipoxy (registered trademark) R-6545" (manufactured by Showa Denko KK).

Vinyl ester resins can be cured by radical polymerization through heating in the presence of a catalyst such as an organic peroxide. The organic peroxides are not particularly limited, but examples include ketone peroxides, peroxyketals, hydroperoxides, diallyl peroxides, diacyl peroxides, peroxy esters, and peroxydicarbonates. By combining these organic peroxides with cobalt metal salts, etc., curing at room temperature is also possible.

The cobalt metal salt is not particularly limited, but examples thereof include cobalt naphthenate, cobalt octylate, and cobalt hydroxide. Among these, cobalt naphthenate and cobalt octylate are preferred.

[Unsaturated polyester resin]
The unsaturated polyester resin is prepared by dissolving an unsaturated polyester, which is a condensation product of an esterification reaction between a polyol compound, an unsaturated polybasic acid, and, if necessary, a saturated polybasic acid, in a polymerizable monomer such as styrene.

As the unsaturated polyester resin, for example, those described in "Polyester Resin Handbook" (published by Nikkan Kogyo Shimbun, 1988) and "Paint Terminology Dictionary" (published by the Color Materials Association, 1993) can be used. Specific examples of unsaturated polyester resins include "Rigolac (registered trademark)" (manufactured by Showa Denko KK).

Unsaturated polyester resins can be cured by radical polymerization through heating in the presence of a catalyst, similar to that of vinyl ester resins.

<Surface treatment>
The metal member 2 preferably has a surface that has been surface-treated.

The resin coating layer 3 is formed on the surface-treated surface of the metal member 2, which makes it easier for it to adhere firmly to the metal member 2.

Surface treatments include, for example, cleaning or degreasing with a solvent or the like, blasting, polishing, etching, and chemical conversion treatment. These surface treatments may be used alone or in combination of two or more. Among these, surface treatments by blasting, polishing, etching, or chemical conversion treatment are preferred.

The surface treatment is performed for the purpose of improving the adhesion of the resin coating layer 3 to the surface of the metal member 2 by cleaning the surface of the metal member 2, generating hydroxyl groups on the surface, or by creating fine irregularities (roughening) on the surface to create an anchor effect.

The surface properties of the metal member 2 that has been surface-treated in the above-mentioned manner may change from those immediately after the surface treatment due to the formation of the resin coating layer 3 on the surface-treated surface. For this reason, it is considered impossible or impractical to specify and express the surface properties of the surface-treated metal member 2 in the resin coating layer laminate 1. Therefore, in this disclosure, the surface of the surface-treated metal member 2 is specified by the method of surface treatment.

The surface treatment can be carried out by a known method. Specific examples of the method include the following:

[Cleaning or degreasing treatment]
Examples of the cleaning or degreasing treatment using a solvent or the like include cleaning the surface of the metal member 2 with an organic solvent such as acetone or toluene, or wiping to degrease the surface.

[Blast treatment]
The blasting treatment includes, for example, shot blasting and sand blasting.

[Polishing process]
Examples of the polishing treatment include buff polishing using an abrasive cloth, roll polishing using abrasive paper (sandpaper), and electrolytic polishing.

[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.

When the metal member 2 contains aluminum, the etching process is preferably an alkaline 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.

The alkali method can be carried out, for example, by immersing the aluminum material in an aqueous solution of sodium hydroxide or potassium hydroxide with a concentration of 3 to 20% by mass at 20 to 70°C for 1 to 15 minutes. Additives such as chelating agents, oxidizing agents, and phosphates may also be added. After immersion, it is preferable to neutralize (de-smut) the material with an aqueous solution of nitric acid with a concentration of 5 to 20% by mass, rinse with water, and dry it.

[Chemical conversion treatment]
The chemical conversion treatment is mainly for forming a chemical conversion film on the surface of the metal member 2. When the metal member 2 contains aluminum, examples of the chemical conversion treatment include boehmite treatment and zirconium treatment, with boehmite treatment being preferred. The chemical conversion treatment is preferably carried out after the etching treatment.

The boehmite treatment is carried out, for example, by treating an aluminum material with hot water at about 90 to 100°C, and a boehmite (aluminum hydrate oxide) film is formed on the surface of the aluminum material. Ammonia, triethanolamine, etc. may be added to the water as a reaction accelerator. For example, the boehmite treatment can be carried out by immersing the aluminum material in hot water at 90 to 100°C containing triethanolamine at a concentration of 0.1 to 5.0 mass% for 3 seconds to 5 minutes. In the boehmite treatment, it is preferable to bake the material after the treatment with hot water in order to form a good boehmite film.

Zirconium treatment is carried out, for example, by immersing the aluminum material in a liquid containing a zirconium salt such as zirconium phosphate, and a coating of a zirconium compound is formed on the surface of the aluminum material. For example, zirconium treatment can be carried out by immersing the aluminum material in a 45-70°C solution of a zirconium treatment chemical conversion agent such as "Palcoat 3762" or "Palcoat 3796" (both manufactured by Nihon Parkerizing Co., Ltd.) for 0.5-3 minutes.

When performing a surface treatment on the metal member 2 containing aluminum, the surface treatment is preferably one or more selected from an etching treatment and a boehmite treatment.

<Functional Group-Containing Layer 4>
Fig. 5 shows a schematic cross-sectional view of a resin coating layer laminate 1 according to another embodiment. The resin coating layer laminate 1 shown in Fig. 5 has a functional group-containing layer 4 laminated between a metal member 2 and a resin coating layer 3 in contact with both of them. The functional group-containing layer 4 has a structure derived from one or more functional groups selected from the following (C1) to (C7).
(C1) one or more functional groups selected from an amino group, a mercapto group, a (meth)acryloyl group, an epoxy group, and an isocyanato group derived from a silane coupling agent; (C2) a functional group formed by the reaction of an amino group derived from a silane coupling agent with an epoxy compound; (C3) a functional group formed by the reaction of a mercapto group derived from a silane coupling agent with one or more compounds selected from an epoxy compound, an isocyanate compound, an epoxy-modified (meth)acrylate compound, and an amino group-containing (meth)acrylate compound; (C4) a functional group formed by the reaction of a (meth)acryloyl group derived from a silane coupling agent with a thiol compound; (C5) a functional group formed by the reaction of an epoxy group derived from a silane coupling agent with one or more compounds selected from an amino compound, a thiol compound, and an amino group-containing (meth)acrylate compound; (C6) an isocyanato group derived from an isocyanate compound; (C7) a mercapto group derived from a thiol compound.

The structure derived from the functional groups in the functional group-containing layer 4 chemically bonds with the metal member 2 and the resin coating layer 3 that are laminated in contact with the functional group-containing layer 4, thereby firmly adhering the metal member 2 and the resin coating layer 3. It is believed that the functional group-containing layer 4 can also contribute to improving the bonding strength between the surface of the resin coating layer 3 side of the resin coating layer laminate 1 and the resin member 5.

The fact that the functional group-containing layer 4 has a structure derived from the functional groups (C1) to (C7) may be confirmed by analysis immediately after the functional group-containing layer 4 is formed on the surface of the metal member 2. However, in the resin coating layer laminate 1, these structures derived from the functional groups are chemically bonded to the resin coating layer 3 and changed, making it impossible or impractical to confirm the presence of the functional groups or structures in the functional group-containing layer 4. For this reason, in the present disclosure, the configuration of the functional group-containing layer 4 is specified based on the functional groups possessed by the silane coupling agent and/or other compounds capable of generating the structures derived from the functional groups (C1) to (C7).

The functional group-containing layer 4 is preferably laminated on the surface of the metal member 2 that has been subjected to the above-mentioned surface treatment. In other words, the metal member 2 is preferably surface-treated before the functional group-containing layer 4 is formed. This allows the metal member 2 and the resin coating layer 3 to be firmly bonded together by a synergistic effect of the surface treatment and the chemical bond caused by the functional group-containing layer 4. The above-mentioned synergistic effect may also improve the bonding strength between the resin coating layer 3 and the resin member 5.

The functional group-containing layer 4 can be formed by treating the surface of the metal member 2 with one or more compounds selected from the following (c1) to (c7) before forming the resin coating layer 3:
(c1) a silane coupling agent having one or more functional groups selected from an amino group, a mercapto group, a (meth)acryloyl group, an epoxy group, and an isocyanato group; (c2) a combination of a silane coupling agent having an amino group and an epoxy compound; (c3) a combination of a silane coupling agent having a mercapto group and one or more compounds selected from an epoxy compound, an isocyanate compound, an epoxy-modified (meth)acrylate compound, and an amino group-containing (meth)acrylate compound; (c4) a combination of a silane coupling agent having a (meth)acryloyl group and a thiol compound; (c5) a combination of a silane coupling agent having an epoxy group and one or more compounds selected from an amino compound, a thiol compound, and an amino group-containing (meth)acrylate compound; (c6) an isocyanate compound; and (c7) a thiol compound.

(c1) to (c7) correspond to the functional groups (C1) to (C7) formed from them, respectively. That is, the treatment with (c1) forms a functional group-containing layer 4 into which the functional group of (C1) is introduced, and the treatment with (c2) forms a functional group-containing layer 4 into which the functional group of (C2) is introduced. The same applies to the treatments with (c3) to (c7).

For example, in the treatment with (c2), when a bifunctional epoxy compound is reacted with an amino group, an epoxy group, which is a functional group possessed by the bifunctional epoxy compound, is introduced to the terminal. Similarly, in the treatment with (c3), when a polyfunctional isocyanate compound is reacted with a mercapto group, an isocyanato group, which is a functional group possessed by the polyfunctional isocyanate compound, is introduced to the terminal.

The method for forming the functional group-containing layer 4 is not particularly limited, but it can be formed by coating the surface of the metal member 2 with the silane coupling agent and/or other compounds shown in (c1) to (c7) by a known coating method such as spray coating or immersion. For example, the metal member 2 can be immersed in a solution of a silane coupling agent or the like with a concentration of 5 to 50 mass % at room temperature to 100°C for 1 minute to 5 days, and then dried at room temperature to 100°C for 1 minute to 5 hours.

[Silane coupling agent]
As the silane coupling agent in (c1) to (c5), for example, a known one used in the surface treatment of glass fiber can be used. The silanol group generated by hydrolysis of the silane coupling agent, or the silanol group of the oligomerized product generated by condensation of the silanol group, bonds with the surface of the metal member 2, particularly with the hydroxyl group generated by the surface treatment, thereby introducing functional groups derived from the silane coupling agent, such as amino groups, mercapto groups, (meth)acryloyl groups, epoxy groups, and isocyanato groups, onto the surface of the metal member 2. These functional groups contribute to the formation of chemical bonds with the compound forming the resin coating layer 3.

These functional groups can generate functional groups that have chemical affinity with the compound that forms the resin coating layer 3 by reacting with the functional groups of a compound other than the silane coupling agent used to form the functional group-containing layer 4. For this reason, in each of the treatments (c2) to (c5), it is preferable to treat the surface of the metal member 2 with a silane coupling agent, and then with a compound that is to be combined with the silane coupling agent.

In this way, the silane coupling agent is preferably used as a compound that forms the functional group-containing layer 4 in order to firmly bond the metal member 2 and the resin coating layer 3 through the functional group-containing layer 4.

The silane coupling agent used has one or more functional groups selected from an amino group, a mercapto group, a (meth)acryloyl group, an epoxy group, and an isocyanato group. These silane coupling agents may be used alone or in combination of two or more.

Examples of silane coupling agents having an amino group include 3-aminopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 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, and N-(vinylbenzyl)-2-aminopropyltrimethoxysilane hydrochloride.

Examples of silane coupling agents having a mercapto group include 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane.

Examples of silane coupling agents having a (meth)acryloyl group include 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, and 3-(meth)acryloxypropyltriethoxysilane.

Examples of silane coupling agents having an epoxy group include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane.

An example of a silane coupling agent having an isocyanato group is 3-isocyanatopropyltriethoxysilane.

[Thiol compounds]
The thiol compound in (c4), (c5) or (c7) is a compound other than a silane coupling agent. The mercapto group of the thiol compound is easily bonded to the surface of the metal member 2, particularly to the hydroxyl group generated by the surface treatment. In addition, when used in combination with a silane coupling agent, the mercapto group of the thiol compound reacts with a functional group such as a (meth)acryloyl group or an epoxy group derived from the silane coupling agent, and can generate a functional group that has chemical affinity with the compound that forms the resin coating layer 3 on the surface of the metal member 2. For this reason, the thiol compound is preferably used as a compound that forms the functional group-containing layer 4 in order to firmly bond the metal member 2 and the resin coating layer 3 through the functional group-containing layer 4.

The thiol compound is not particularly limited, but examples thereof include pentaerythritol tetrakis(3-mercaptopropionate) "jER Cure (registered trademark) QX40" (manufactured by Mitsubishi Chemical Corporation), "Polythiol (registered trademark) QE-340M" (manufactured by Toray Fine Chemicals Co., Ltd.); ether-based primary thiol compound "Cup Cure (registered trademark) 3-800" (manufactured by Cognis); 1,4-bis(3-mercaptobutyryloxy)butane "Karenz MT (registered trademark) BD1" (manufactured by Showa Denko K.K.); pentaerythritol tetrakis(3-mercaptobutyrate) "Karenz MT (registered trademark) PE1" (manufactured by Showa Denko K.K.); and 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione "Karenz MT (registered trademark) NR1" (manufactured by Showa Denko K.K.). These thiol compounds may be used alone or in combination of two or more.

[Isocyanate Compound]
The isocyanate compound in (c3) or (c6) is a compound other than a silane coupling agent. The isocyanate group of the isocyanate compound is likely to bond with the surface of the metal member 2, particularly with the hydroxyl group generated by the surface treatment. In addition, when used in combination with a silane coupling agent, it can react with a functional group such as a mercapto group derived from the silane coupling agent to generate a functional group that has chemical affinity with the compound that forms the resin coating layer 3 on the surface of the metal member 2. For this reason, the isocyanate compound is preferably used as a compound that forms the functional group-containing layer 4 in order to firmly bond the metal member 2 and the resin coating layer 3 through the functional group-containing layer 4.

The isocyanate compound is not particularly limited, but examples thereof include polyfunctional isocyanates such as diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), and isophorone diisocyanate (IPDI); and isocyanate compounds having a radical reactive group such as 2-isocyanatoethyl methacrylate "Karenz MOI (registered trademark)", 2-isocyanatoethyl acrylate "Karenz AOI (registered trademark)" and "AOI-VM (registered trademark)", and 1,1-(bisacryloyloxyethyl)ethyl isocyanate "Karenz BEI (registered trademark)" (all manufactured by Showa Denko KK). The isocyanate compounds may be used alone or in combination of two or more kinds.

[Epoxy Compound]
The epoxy compound in (c2) or (c3) is a compound other than a silane coupling agent. The epoxy group of the epoxy compound reacts with a functional group such as an amino group or a mercapto group derived from the silane coupling agent to generate a functional group having chemical affinity with the compound forming the resin coating layer 3 on the surface of the metal member 2. For this reason, the epoxy compound is preferably used as a compound forming the functional group-containing layer 4 in order to firmly bond the metal member 2 and the resin coating layer 3 via the functional group-containing layer 4.

As the epoxy compound, known epoxy compounds can be used, and polyfunctional epoxy compounds and compounds having an alkenyl group in addition to an epoxy group are preferred. Examples of epoxy compounds include allyl glycidyl ether, 1,6-hexanediol diglycidyl ether, and bifunctional epoxy resins. The epoxy compound may be an alicyclic epoxy compound. Examples of alicyclic epoxy compounds include 1,2-epoxy-4-vinylcyclohexane "Celloxide (registered trademark) 2000" and 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate "Celloxide (registered trademark) 2021P" (both manufactured by Daicel Corporation). These epoxy compounds may be used alone or in combination of two or more kinds.

[Amino Compounds]
The amino compound in (c5) is a compound other than a silane coupling agent. The amino group of the amino compound can react with a functional group such as an epoxy group derived from the silane coupling agent to generate a functional group that has chemical affinity with the compound that forms the resin coating layer 3 on the surface of the metal member 2. For this reason, the amino compound is preferably used as a compound that forms the functional group-containing layer 4 in order to firmly bond the metal member 2 and the resin coating layer 3 through the functional group-containing layer 4.

As the amino compound, known amino compounds can be used, and amino compounds having two or more amino groups in one molecule and compounds having an alkenyl group in addition to an amino group (including an amide group) are preferred. Examples of amino compounds include ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-diaminobutane, hexamethylenediamine, 2,5-dimethyl-2,5-hexanediamine, 2,2,4-trimethylhexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, 4-aminomethyloctamethylenediamine, 3,3'-iminobis(propylamine), 3,3'-methyl ... Examples of such amino compounds include bis(propylamine), bis(3-aminopropyl)ether, 1,2-bis(3-aminopropyloxy)ethane, menthene diamine, isophorone diamine, bisaminomethylnorbornane, bis(4-aminocyclohexyl)methane, bis(4-amino-3-methylcyclohexyl)methane, 1,3-diaminocyclohexane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, and aminoethylpiperazine. These amino compounds may be used alone or in combination of two or more.

[Epoxy-modified (meth)acrylate compound]
The epoxy-modified (meth)acrylate compound in (c3) is a compound other than the silane coupling agent, and has an epoxy group and a (meth)acryloyl group. Therefore, by reacting with a functional group such as a mercapto group derived from the silane coupling agent, a functional group having chemical affinity with the compound forming the resin coating layer 3 on the surface of the metal member 2 can be generated. Therefore, the epoxy-modified (meth)acrylate compound is preferably used as a compound forming the functional group-containing layer 4 in order to firmly bond the metal member 2 and the resin coating layer 3 through the functional group-containing layer 4.

Examples of epoxy-modified (meth)acrylate compounds include glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl methacrylate "Cyclomer (registered trademark) M100", and compounds in which a portion of the multifunctional epoxy compounds in (c2) and (c3) described above has been (meth)acryloylated. These epoxy-modified (meth)acrylate compounds may be used alone or in combination of two or more kinds.

[Amino group-containing (meth)acrylate compound]
The amino group-containing (meth)acrylate compound in (c3) or (c5) is a compound other than a silane coupling agent, and has an amino group and a (meth)acryloyl group. Therefore, by reacting with a functional group such as a mercapto group or an epoxy group derived from the silane coupling agent, a functional group having chemical affinity with the compound forming the resin coating layer 3 on the surface of the metal member 2 can be generated. Therefore, the amino group-containing (meth)acrylate compound is preferably used as a compound forming the functional group-containing layer 4 in order to firmly bond the metal member 2 and the resin coating layer 3 through the functional group-containing layer 4.

Examples of amino group-containing (meth)acrylate compounds include (meth)acrylamide and compounds in which a part of the amino compound having two or more amino groups in one molecule in (c5) above is (meth)acryloylated. These amino group-containing (meth)acrylate compounds may be used alone or in combination of two or more kinds.

[In-vehicle camera 10 (metal-resin joint)]
Fig. 6 is a schematic cross-sectional view of a state in which a metal member 2 and a resin member 5 are bonded via a resin coating layer 3, and is a diagram showing, for example, a circled portion X in Fig. 3. In a vehicle-mounted camera (metal-resin bonded body) 10 shown in Fig. 6, a surface of the resin coating layer laminate 1 (a laminate of the resin coating layer 3 and the first housing part 12) on the resin coating layer 3 side is bonded to a resin member 5 (14).

The resin coating layer 3 exhibits high bonding strength with the resin member 5 even when exposed to high temperatures exceeding 100°C, so the vehicle-mounted camera 10 in which the metal member 2 and the resin member 5 are bonded via the resin coating layer 3 is firmly bonded, and thermal deterioration of the joint is suppressed. In particular, when a resin member 5 with excellent heat resistance is bonded, a vehicle-mounted camera 10 with excellent heat resistance can be obtained.

As shown in FIG. 6, in the vehicle-mounted camera 10, the metal member 2 (first housing part 12) of the resin coating layer laminate 1 and the resin member 5 (second housing part 14) are joined via the resin coating layer 3 (included in the resin coating layer laminate 1), and the resin coating layer 3 and the resin member 5 are welded together.

In the vehicle-mounted camera 10 of this embodiment, when the housing parts 12, 14 that make up the housing are assembled and joined, they are joined via the resin coating layer 3 without using a mechanical joining method such as screwing, so excellent airtightness can be achieved. In addition, by not using a mechanical joining method such as screwing, weight reduction can also be achieved.

As described above with reference to FIG. 3, the vehicle-mounted camera 10 of this embodiment can dissipate heat generated in the module 20 via the thermally conductive sheet 22 to the first housing part 12, which is made of aluminum, for example, and can then efficiently dissipate the heat to the outside in the heat sink area 12a of the first housing part 12, thereby achieving excellent heat dissipation.

Furthermore, unlike cases in which the housing parts 12, 14, which are molded separately, are bonded together using an adhesive, the vehicle-mounted camera 10 of this embodiment is manufactured by the above-mentioned method without going through multiple steps (frame treatment of the resin surface, surface treatment such as plasma treatment, primer coating, adhesive application, adhesive curing, etc.), and therefore can be manufactured inexpensively.

As a result, this embodiment can provide an in-vehicle camera that can achieve excellent airtightness and excellent heat dissipation, and can be manufactured at low cost.

<Resin member 5>
The resin member 5 to be bonded to the metal member 2 is not particularly limited and may be a general synthetic resin. Since the resin coating layer 3 exhibits high bonding strength with the resin member 5 even when exposed to high temperatures exceeding 100° C. and suppresses thermal deterioration of the bonded portion between the metal member 2 and the resin member 5, a heat-resistant resin is preferably used in order to obtain an on-board camera 10 having excellent heat resistance and a particularly strong bonding strength.

Examples of heat-resistant resins include resins used in automobile parts, such as polyetherimide resin, polybutylene terephthalate resin, polyphenylene sulfone resin, glass fiber reinforced polyphenylene terephthalate, and glass fiber reinforced nylon. For example, carbon fiber-containing sheet molding compound (SMC), bulk molding compound (BMC), and other molded products such as carbon fiber-reinforced plastic (CFRP) and glass fiber reinforced plastic (GFRP) can also be used. SMC is a sheet-like molded product obtained by impregnating a mixture of unsaturated polyester resin and/or vinyl ester resin, polymerizable unsaturated monomer, hardener, low shrinkage agent, filler, etc., into reinforcing fibers such as carbon fiber.

The thickness of the resin coating layer 3 in the vehicle-mounted camera 10 depends on the material of the resin member 5 to be joined with the resin coating layer 3 and the contact area of the joint, but from the viewpoint of sufficient joint strength and heat resistance, it is preferably 1 μm to 10 mm, more preferably 10 μm to 2 mm, and even more preferably 20 μm to 500 μm.

The resin coating layer 3 has a stress relaxation effect that suppresses thermal deformation of the vehicle-mounted camera 10 or separation of the metal member 2 and the resin member 5 caused by the difference in thermal expansion coefficient between the metal member 2 and the resin member 5, even when exposed to high temperatures exceeding 100°C. This suppresses thermal deterioration of the joints of the vehicle-mounted camera 10.

[Method of manufacturing the vehicle-mounted camera 10]
A method for manufacturing the vehicle-mounted camera 10 (metal-resin bonded body) of one embodiment includes a method for bonding the resin member 5 to the resin coating layer 3 of the resin coating layer laminate 1 by at least one method selected from the group consisting of hot air welding, hot plate welding, ultrasonic welding, vibration welding, electromagnetic induction method, high frequency method, laser method, hot plate welding, and heat pressing. The resin member 5 can be produced separately from the resin coating layer laminate 1.

Another embodiment of the manufacturing method for the vehicle-mounted camera 10 (metal-resin bonded body) includes a method in which a resin member 5 is molded on top of the resin coating layer 3 of the resin coating layer laminate 1 by injection molding, press molding, filament winding molding, hand layup molding, transfer molding, or the like, and in the process, the surface of the resin coating layer laminate 1 facing the resin coating layer 3 is bonded to the resin member 5.

From the viewpoints of reducing the demands on the manufacturing equipment, simplifying the manufacturing process, and allowing freedom in designing the resin member, it is advantageous to manufacture the vehicle-mounted camera 10 (metal-resin bonded body) by a heat press method. Specifically, the vehicle-mounted camera 10 can be manufactured by heating the resin coating layer 3 and pressing the metal member 2 and the resin member 5 together so that the heated resin coating layer 3 is interposed between them. The heating temperature of the resin coating layer 3 depends on the melting point or softening point of the resin to be bonded, and is preferably 100°C to 350°C. For example, when the resin is nylon 6, the heating temperature is preferably 230°C. For a resin coating layer 3 that has a melting point, the heating temperature is preferably the melting point ±5°C, and for a resin coating layer 3 that has a softening point, the heating temperature is preferably the softening point ±15°C. The pressure during pressing is preferably 0.005 MPa to 10 MPa.

In another embodiment, the resin coating layer laminate 1' may be formed by having one or more resin coating layers 3' laminated on the resin member 5 instead of the metal member 2. The resin coating layer 3' can be formed on the surface of the resin member 5 using the same material as the resin coating layer 3 described above. In this embodiment, the epoxy resin layer is preferably formed so as to be in direct contact with the resin member 5. Therefore, when the resin coating layer 3' is made of multiple layers, it is preferable to laminate other layers, such as a curable resin layer, on the epoxy resin layer after forming the epoxy resin layer on the resin member 5. In this embodiment, the bonding between the metal member 2 and the resin member 5 can be carried out by replacing the above-mentioned "metal member 2" with the "resin member 5" in this embodiment, the above-mentioned "resin member 5" with the "metal member 2" in this embodiment, and the above-mentioned "resin coating layer laminate 1" with the "resin coating layer laminate 1'".

In yet another embodiment, the resin coating layer laminates 1 and 1' are formed by laminating the above-mentioned resin coating layers 3 and 3' on the metal member 2 and the resin member 5, respectively, and the resin coating layer 3 of the resin coating layer laminate 1 and the resin coating layer 3' of the resin coating layer laminate 1' are welded. As a result, the metal member 2 and the resin member 5 are joined via the resin coating layers 3, 3'. In this embodiment, the vehicle-mounted camera 10 (metal-resin joint) can be manufactured by welding the resin coating layer 3 of the resin coating laminate 1 and the resin coating layer 3' of the resin coating laminate 1' using at least one method selected from the group consisting of hot air welding, hot plate welding, ultrasonic welding, vibration welding, electromagnetic induction method, high frequency method, laser method, hot plate welding, and heat pressing, preferably heat pressing.

The manufacturing method of this embodiment is characterized by the joining of the metal member 2 and the resin member 5, but in the above explanation, the first housing part 12 shown in FIG. 3 is used as the metal member 2, and the second housing part 14 shown in the same figure is used as the resin member 5. However, the resin member 5 is not limited to the second housing part 14, and also includes, for example, a resin member mounted on the first housing part 12 (for example, a resin positioning pin or a resin bracket member that holds various sensors).

Although several embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

The following are examples of tests and comparative tests related to the present invention, but the present invention is not limited to these examples.

Details of the main raw materials used in the following practical test examples and comparative test examples are shown below.

[Metal Members]
Aluminum plate: Aluminum alloy; Al-Mg-Si system A6063, 18 mm x 45 mm, thickness 1.5 mm
・Iron plate: 18mm x 45mm, thickness 1.5mm
SUS304 plate: Stainless steel SUS304 (Cr-Ni type), 18 mm x 45 mm, thickness 1.5 mm
・Copper plate: 18mm x 45mm, thickness 1.5mm

[Silane coupling agent]
KBM-903: 3-aminopropyltrimethoxysilane, "KBM-903" manufactured by Shin-Etsu Chemical Co., Ltd.
KBM-503: 3-methacryloxypropyltrimethoxysilane, "KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.

[Composition (A)]
<Difunctional Epoxy Resin>
jER1007: "jER (registered trademark) 1007" manufactured by Mitsubishi Chemical Corporation
<Dihydric phenol compound>
・BPS: Bisphenol S

[Composition (B)]
PG-100: Epoxy resin having a fluorene skeleton, "OGSOL (registered trademark) PG-100" manufactured by Osaka Gas Chemicals Co., Ltd.
TAM-005: Phenolic compound having an imidazolidinone skeleton, novolac-type phenolic resin "TAM-005" manufactured by Aica Kogyo Co., Ltd.
NC-3000: Epoxy resin having a biphenyl skeleton, "NC-3000" manufactured by Nippon Kayaku Co., Ltd.
APG: Allylphenol compound, "APG low viscosity allylphenol resin" manufactured by Gun-ei Chemical Industry Co., Ltd.
BMI-1000: 4,4'-diphenylmethane bismaleimide, "BMI-1000" manufactured by Daiwa Chemical Industry Co., Ltd.
BPEF: Bisphenoxyethanol fluorene, "BPEF" manufactured by Osaka Gas Chemicals Co., Ltd.

[Resin member]
PEI: Polyetherimide resin, "Ultem (registered trademark) 1000" manufactured by SABIC Japan LLC
PBT: polybutylene terephthalate resin, SABIC Japan LLC "Valox (registered trademark) 507", containing 30% by mass of glass fiber PPS: polyphenylene ether resin, DIC Corporation "FZ-2140", containing 40% by mass of glass fiber

[Production of resin coating layer laminate]
By carrying out each step shown in the following production example, a resin coating layer laminate in which a resin coating layer was laminated on the surface of a metal member was produced.

<Production Example 1>
(Surface treatment process)
An aluminum plate as a metal member was etched by immersing it in a 5% by mass aqueous sodium hydroxide solution for 1.5 minutes, neutralizing it with a 5% by mass aqueous nitric acid solution, rinsing it with water, and drying it. The aluminum plate after the etching process was boiled in pure water for 10 minutes and then baked at 250° C. for 10 minutes to perform a boehmite treatment.

(Functional group-containing layer formation step)
2 g of a silane coupling agent KBM-903 was dissolved in 1000 g of industrial ethanol. The obtained silane coupling agent solution was heated to 70° C., and the aluminum plate after the boehmite treatment was immersed in the silane coupling agent solution for 20 minutes. Thereafter, the aluminum plate was taken out and dried at room temperature for 1 hour to form a functional group-containing layer on the boehmite-treated surface.

(Resin coating layer forming process)
100 g of epoxy resin jER1007, 6.2 g of bisphenol S, and 0.4 g of triethylamine were dissolved in 197 g of acetone to obtain a composition (A).

100 g of epoxy resin PG-100 having a fluorene skeleton, 61.9 g of phenolic compound TAM-005 having an imidazolidinone skeleton, and 1.3 g of triethylamine were dissolved in 300 g of acetone to obtain composition (B1-1).

A resin composition in which composition (A) and composition (B1-1) were mixed in a mass ratio of 40/60 excluding acetone was spray-coated onto the surface of the functional group-containing layer of the aluminum plate so that the thickness after drying would be 70 μm. After leaving it in air (relative humidity 50%) at room temperature for 30 minutes to volatilize the solvent, it was left in a 150°C oven for 30 minutes to react, and then cooled to room temperature to form a resin coating layer, thereby obtaining a resin coating layer laminate E1.

<Production Example C1>
A comparative resin coating layer laminate C1 was produced in the same manner as in Production Example 1, except that the resin composition used in the resin coating layer forming step was only the composition (A).

<Production Example 2>
(Surface treatment process)
As the metal member, an iron plate was polished with #100 sandpaper and then degreased with acetone.

(Resin coating layer forming process)
100 g of epoxy resin NC-3000 having a biphenyl skeleton, 91.9 g of phenol compound TAM-005 having an imidazolidinone skeleton, and 1.54 g of triethylamine were dissolved in 356.5 g of acetone to obtain a composition (B2).

A resin composition prepared by blending composition (A) and composition (B2) prepared in Production Example 1 in a mass ratio of 50/50 (excluding acetone) was spray-applied to the polished surface of an iron plate so that the thickness after drying would be 50 μm. After leaving it in air (relative humidity 50%) at room temperature for 30 minutes to evaporate the solvent, it was left in a 150°C oven for 30 minutes to react, and then cooled to room temperature to form a resin coating layer, thereby obtaining a resin coating layer laminate E2.

<Production Example C2>
A comparative resin coating layer laminate C2 was produced in the same manner as in Production Example 2, except that the resin composition used in the resin coating layer forming step was only the composition (A).

<Production Example 3>
(Surface treatment process)
As the metal member, a SUS304 plate was polished with #100 sandpaper and then degreased with acetone.

(Functional group-containing layer formation step)
2 g of a silane coupling agent KBM-503 was dissolved in 1000 g of industrial ethanol. The obtained silane coupling agent solution was heated to 70° C., and the polished SUS304 plate was immersed in the silane coupling agent solution for 20 minutes. Thereafter, the SUS304 plate was taken out and dried at room temperature for 1 hour to form a functional group-containing layer on the surface of the SUS304 plate.

(Resin coating layer forming process)
100 g of the allylphenol compound APG and 100 g of the bismaleimide compound BMI-1000 were dissolved in 371 g of acetone to obtain a composition (B3).

A resin composition prepared by blending composition (A) and composition (B3) prepared in Manufacturing Example 1 in a mass ratio of 70/30 (excluding acetone) was spray-coated onto the surface of the functional group-containing layer of a SUS304 plate so that the thickness after drying was 50 μm. After leaving it in air (relative humidity 50%) at room temperature for 30 minutes to evaporate the solvent, it was left in a 150°C oven for 30 minutes to react, and then cooled to room temperature to form a resin coating layer, thereby obtaining a resin coating layer laminate E3.

<Production Example C3>
A comparative resin coating layer laminate C3 was produced in the same manner as in Production Example 3, except that the resin composition used in the resin coating layer forming step was only the composition (A).

<Production Example 4>
(Surface treatment process)
As the metal member, a copper plate was polished with #1000 sandpaper and then degreased with acetone.

(Functional group-containing layer formation step)
2 g of a silane coupling agent KBM-903 was dissolved in 1000 g of industrial ethanol. The obtained silane coupling agent solution was heated to 70° C., and the copper plate after the polishing treatment was immersed in the silane coupling agent solution for 20 minutes. The copper plate was then taken out and dried to form a functional group-containing layer on the surface of the copper plate.

(Resin coating layer forming process)
100 g of the epoxy resin PG-100 having a fluorene skeleton, 84.3 g of the phenol compound BPEF having a fluorene skeleton, and 1.4 g of triethylamine were dissolved in 342 g of acetone to obtain a composition (B1-2).

A resin composition prepared by blending composition (A) and composition (B1-2) prepared in Manufacturing Example 1 in a mass ratio of 60/40 (excluding acetone) was spray-coated onto the surface of the functional group-containing layer of the copper plate so that the thickness after drying was 50 μm. After leaving it in air (relative humidity 50%) at room temperature for 30 minutes to evaporate the solvent, it was left in a 150°C oven for 30 minutes to react, and then cooled to room temperature to form a resin coating layer, thereby obtaining resin coating layer laminate E4.

[Production of Metal-Resin Joint]
The produced resin coating layer laminate or comparative resin coating layer laminate was bonded to various resin members by the methods shown in the following Working Test Examples and Comparative Test Examples, thereby producing metal-resin bonded bodies in which the surface of the resin coating layer laminate on the resin coating layer side was bonded to a resin member.

The metal-resin joint was manufactured as a test piece conforming to ISO19095 (resin member width 10 mm x length 45 mm x thickness 3 mm, joint length between resin member and metal member 5 mm, width 10 mm) for use in the joint strength evaluation test described below.

<Test Example 1>
A resin member PEI (width 10 mm × length 45 mm × thickness 3 mm) was produced by injection molding PEI using an injection molding machine (Sumitomo Heavy Industries, Ltd. "SE100V", cylinder temperature 370°C, tool temperature 150°C, injection speed 14 mm/sec, peak/holding pressure 160/140 [MPa/MPa]).

The resin coating layer of the resin coating layer laminate E1 obtained in Manufacturing Example 1 was heated to 225°C, and the surface of the resin coating layer laminate E1 on the resin coating layer side and the resin member PEI were overlapped so that the joint overlapped length was 5 mm and width was 10 mm, and then pressure was applied to 0.1 MPa to press them together, thereby producing a metal-resin joint.

Comparative Test Example 1
Using the comparative resin coating layer laminate C1 obtained in Production Example C1, the same operation as in Experimental Test Example 1 was carried out to produce a metal-resin bonded body.

<Test Example 2>
A resin member PBT (width 10 mm × length 45 mm × thickness 3 mm) was produced by injection molding PBT using an injection molding machine (Sumitomo Heavy Industries, Ltd. "SE100V", cylinder temperature 245°C, tool temperature 80°C, injection speed 10 mm/sec, peak/holding pressure 100/80 [MPa/MPa]).

The resin coating layer of the resin coating layer laminate E2 obtained in Manufacturing Example 2 was heated to 225°C, and the surface of the resin coating layer side of the resin coating layer laminate E2 and the resin member PBT were overlapped so that the joint overlap length was 5 mm and width was 10 mm, and then pressure was applied to 0.1 MPa to press them together, thereby producing a metal-resin joint.

Comparative Test Example 2
Using the comparative resin coating layer laminate C2 obtained in Production Example C2, the same operation as in Experimental Test Example 2 was carried out to produce a metal-resin joint body.

<Test Example 3>
A resin part PPS (width 10 mm × length 45 mm × thickness 3 mm) was produced by injection molding PPS using an injection molding machine (Sumitomo Heavy Industries, Ltd. "SE100V", cylinder temperature 310° C., tool temperature 150° C., injection speed 14 mm/sec, peak/holding pressure 160/140 [MPa/MPa]).

The resin coating layer of the resin coating layer laminate E3 obtained in Manufacturing Example 3 was heated to 290°C, and the surface of the resin coating layer side of the resin coating layer laminate E3 and the resin member PPS were overlapped so that the joint overlap length was 5 mm and width was 10 mm, and then pressure was applied to 0.1 MPa to press them together, thereby producing a metal-resin joint.

Comparative Test Example 3
Using the comparative resin coating layer laminate C3 produced in Production Example C3, the same operation as in Experimental Test Example 3 was carried out to produce a metal-resin joint body.

<Test Example 4>
A resin member PEI was pressure-bonded to the surface of the resin coating layer side of the resin coating layer laminate E4 obtained in Production Example 4 in the same manner as in Experimental Test Example 1, thereby producing a metal-resin bonded body.

[Bonding strength evaluation]
For each test piece of the metal-resin bonded body produced in the above-mentioned Working Test Example and Comparative Test Example, after leaving it for one day at each temperature shown in the following Table 1 within a range of 23 to 160° C., the tensile shear strength (bonding strength) was measured using a tensile tester (Universal testing machine autograph “AG-IS” manufactured by Shimadzu Corporation, load cell 10 kN, tensile speed 10 mm/min, measurement temperature 23° C., 50% RH) according to a method in accordance with ISO 19095-1 to 4.

These measurement results are shown in Table 1. If the test piece's joint peeled off during exposure to high temperatures exceeding 130°C, making measurement impossible, this is indicated by a "-" in the tensile shear strength column in Table 1.

As is clear from Table 1, since the resin coating layer is formed from an epoxy resin composition containing composition (A) and composition (B), it was found that the metal-resin bonded body retains high tensile shear strength (bonding strength) even after being exposed to high temperatures exceeding 100°C, and thermal deterioration of the bonded portion between the metal member and the resin member is suppressed. In particular, in practical test examples 1 and 4, it was confirmed that the tensile shear strength was high, at 15 MPa or more, even at 150°C.

These results show that the resin coating layer disclosed herein can suppress thermal deterioration of the joint of the metal-resin joint and improve heat resistance.

The present invention can be used for vehicle-mounted cameras and their manufacturing methods.

REFERENCE SIGNS LIST 1 resin coating layer laminate 2 metal member 3 resin coating layer 4 functional group-containing layer 5 resin member 10 vehicle-mounted camera (metal-resin joint)
REFERENCE SIGNS LIST 11 bracket 12 first housing part 12a heat sink area 14 second housing part 16 connector 18 electronic board 20 module 22 thermally conductive sheet X circled area

Claims (9)

A vehicle-mounted camera including a metal member, a resin member, and one or more resin coating layers laminated on at least one of the metal member and the resin member,
the metal member is a first housing part,
the resin member is a second housing part,
the metal member and the resin member are joined via the resin coating layer,
at least one of the resin coating layers is formed from a cured product of an epoxy resin composition containing a composition (A) including a difunctional epoxy resin and a dihydric phenol compound, and a composition (B);
The composition (B) includes at least one combination selected from the following (B1) to (B3):
The surface of the metal member opposite to the surface on which the resin coating layer is laminated has an uneven shape.
(B1) A combination of an epoxy resin having a fluorene skeleton and a phenol compound having one or more skeletons selected from a fluorene skeleton, an imidazolidinone skeleton, and an aminotriazine skeleton. (B2) A combination of an epoxy resin having a biphenyl skeleton and a phenol compound having one or more skeletons selected from a fluorene skeleton, an imidazolidinone skeleton, and an aminotriazine skeleton. (B3) A combination of an allylphenol compound and a bismaleimide compound. The vehicle-mounted camera according to claim 1, wherein the content of the composition (B) in the epoxy resin composition is 10 to 80 parts by mass per 100 parts by mass of the total content of the composition (A) and the composition (B). The vehicle-mounted camera according to claim 1 or 2, wherein the surface of the metal member has a surface that has been surface-treated with one or more treatments selected from blasting, polishing, etching, and chemical conversion treatment. a functional group-containing layer is provided between the metal member and the resin coating layer and is laminated in contact with the metal member and the resin coating layer,
The vehicle-mounted camera according to any one of claims 1 to 3, wherein the functional group-containing layer has a structure derived from one or more functional groups selected from the following (C1) to (C7).
(C1) one or more functional groups selected from an amino group, a mercapto group, a (meth)acryloyl group, an epoxy group, and an isocyanato group derived from a silane coupling agent; (C2) a functional group formed by the reaction of an amino group derived from a silane coupling agent with an epoxy compound; (C3) a functional group formed by the reaction of a mercapto group derived from a silane coupling agent with one or more compounds selected from an epoxy compound, an isocyanate compound, an epoxy-modified (meth)acrylate compound, and an amino group-containing (meth)acrylate compound; (C4) a functional group formed by the reaction of a (meth)acryloyl group derived from a silane coupling agent with a thiol compound; (C5) a functional group formed by the reaction of an epoxy group derived from a silane coupling agent with one or more compounds selected from an amino compound, a thiol compound, and an amino group-containing (meth)acrylate compound; (C6) an isocyanato group derived from an isocyanate compound; (C7) a mercapto group derived from a thiol compound. The resin coating layer is a plurality of layers, and further includes a resin coating layer formed from a cured product of a curable resin,
The vehicle-mounted camera according to any one of claims 1 to 4, wherein the curable resin is at least one selected from the group consisting of allyl-modified maleimide resin, urethane resin, epoxy resin, vinyl ester resin, and unsaturated polyester resin. The vehicle-mounted camera according to any one of claims 1 to 5, wherein the metal member includes an aluminum material, and the thermal conductivity of the aluminum material is 150 W/(m·K) or more. The vehicle-mounted camera according to any one of claims 1 to 6, wherein the metal member includes an aluminum extrusion material, and the aluminum extrusion material has a thermal conductivity of 180 W/(m·K) or more and a tensile strength of 150 MPa or more. The vehicle-mounted camera according to any one of claims 1 to 6, wherein the metal member includes an aluminum forging, and the aluminum forging has a thermal conductivity of 180 W/(m·K) or more and a tensile strength of 150 MPa or more. The method for manufacturing an in-vehicle camera according to any one of claims 1 to 8, comprising heating the resin coating layer and bonding the metal member and the resin member by pressing the metal member and the resin member together so that the heated resin coating layer is interposed between the metal member and the resin member.

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