JP7494950B2 - Vehicle-mounted camera and its manufacturing method - Google Patents

Description

The present disclosure relates to an on-board camera that can be attached to the windshield or other surface of an automobile, and a method for manufacturing the same.

Conventionally, vehicle-mounted cameras with various functions incorporating various modules have been known, and efforts have been made to increase the freedom of arrangement of these modules.

Patent Document 1 (JP 2017-139700 A) discloses an in-vehicle camera including an upper upper housing part located on an upper side within the vehicle cabin, a lower lower housing part that cooperates with the upper housing part to form a space that separates the vehicle from the outside, a board arranged within a housing formed by the upper and lower housing parts, a camera module attached to the surface of the board facing the upper housing part, a board connector provided on the surface of the board facing the upper housing part, and a cable connecting the board connector and the camera connector of the camera module.

JP 2017-139700 A

The modules built into in-vehicle cameras contain a wide variety of precision instruments, and because these instruments are highly vulnerable to water vapor, dirt, and dust, the casing that covers the modules needs to be airtight.

As mentioned above, in order to increase the freedom in module placement, it is possible to give the components that make up the housing that covers the module complex shapes and join these components together. However, if a mechanical joining method such as screwing is used, there is a risk that good airtightness cannot be achieved due to loosening of the screws, etc.

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

The present disclosure includes the following aspects:

[1] A first resin member having a thermoplastic resin material;
a second resin member having a thermoplastic resin material;
A vehicle-mounted camera comprising one or more primer layers laminated on at least one of the thermoplastic resin material of the first resin member and the thermoplastic resin material of the second resin member,
The vehicle-mounted camera includes a housing having at least a first part and a second part, and at least one module housed in the housing;
the first resin member is one of the first part and the second part,
the second resin member is the other of the first part and the second part,
the first resin member and the second resin member are welded together via the primer layer,
At least one of the primer layers is an in-situ polymerizable composition layer formed by polymerizing an in-situ polymerizable composition on the thermoplastic resin material.
[2] The vehicle-mounted camera according to [1], wherein the in-situ polymerization type composition layer is a layer that is in direct contact with the thermoplastic resin material.
[3] The vehicle-mounted camera according to any one of [1] and [2], wherein the in-situ polymerization type composition contains at least one of the following (1) to (7).
(1) A combination of a bifunctional isocyanate compound and a diol (2) A combination of a bifunctional isocyanate compound and a bifunctional amino compound (3) A combination of a bifunctional isocyanate compound and a bifunctional thiol compound (4) A combination of a bifunctional epoxy compound and a diol (5) A combination of a bifunctional epoxy compound and a bifunctional carboxyl compound (6) A combination of a bifunctional epoxy compound and a bifunctional thiol compound (7) A monofunctional radical polymerizable monomer [4] The in-situ polymerization type composition is a composition containing at least one of the following (1) to (7), and a maleic anhydride-modified polypropylene or a modified polyphenylene ether. The vehicle-mounted camera according to either [1] or [2].
(1) A combination of a bifunctional isocyanate compound and a diol (2) A combination of a bifunctional isocyanate compound and a bifunctional amino compound (3) A combination of a bifunctional isocyanate compound and a bifunctional thiol compound (4) A combination of a bifunctional epoxy compound and a diol (5) A combination of a bifunctional epoxy compound and a bifunctional carboxy compound (6) A combination of a bifunctional epoxy compound and a bifunctional thiol compound (7) A monofunctional radical polymerizable monomer [5] The in-situ polymerization type composition is a composition containing at least one of the following (1) to (7), and a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material. The vehicle-mounted camera according to either [1] or [2].
(1) A combination of a bifunctional isocyanate compound and a diol (2) A combination of a bifunctional isocyanate compound and a bifunctional amino compound (3) A combination of a bifunctional isocyanate compound and a bifunctional thiol compound (4) A combination of a bifunctional epoxy compound and a diol (5) A combination of a bifunctional epoxy compound and a bifunctional carboxy compound (6) A combination of a bifunctional epoxy compound and a bifunctional thiol compound (7) A monofunctional radical polymerizable monomer [6] The in-situ polymerization type composition is a composition containing at least one of the following (1) to (7), maleic anhydride modified polypropylene or modified polyphenylene ether, and a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material. The vehicle-mounted camera according to either [1] or [2].
(1) A combination of a bifunctional isocyanate compound and a diol (2) A combination of a bifunctional isocyanate compound and a bifunctional amino compound (3) A combination of a bifunctional isocyanate compound and a bifunctional thiol compound (4) A combination of a bifunctional epoxy compound and a diol (5) A combination of a bifunctional epoxy compound and a bifunctional carboxy compound (6) A combination of a bifunctional epoxy compound and a bifunctional thiol compound (7) A monofunctional radical polymerizable monomer [7] The vehicle-mounted camera according to any one of [3] to [6], wherein the in-situ polymerization type composition contains the (4), and the diol of the (4) is a bifunctional phenol compound.
[8] The primer layer has a curable resin layer formed from a composition containing a curable resin between the in-situ polymerization type composition layer and the thermoplastic resin material. The vehicle-mounted camera according to any one of [1], [3] to [7].
[9] The vehicle-mounted camera according to [8], wherein the curable resin is at least one selected from the group consisting of a urethane resin, an epoxy resin, a vinyl ester resin, and an unsaturated polyester resin.
[10] The vehicle-mounted camera according to any one of [1] to [9], wherein both the first resin member and the second resin member have the primer layer, and the primer layer of the first resin member and the primer layer of the second resin member are welded together.
[11] The vehicle-mounted camera according to any one of [1] to [10], wherein a monomer having a maximum content among the monomers constituting the thermoplastic resin constituting the thermoplastic resin material of the second resin member is the same as a monomer having a maximum content among the monomers constituting the thermoplastic resin constituting the thermoplastic resin material of the first resin member, and the content of each of the monomers is 70 mass% or more.
[12] The thermoplastic resin material of the first resin member or the second resin member contains polypropylene and at least one reinforcing material selected from the group consisting of talc, glass fiber, and carbon fiber, and the first resin member or the second resin member has a tensile strength of 40 MPa or more and a Young's modulus of 3 GPa or more. The vehicle-mounted camera described in any one of [1] to [11].
[13] The thermoplastic resin material of the first resin member or the second resin member contains polyetherimide and at least one reinforcing material selected from the group consisting of talc, glass fiber, and carbon fiber, and the first resin member or the second resin member has a tensile strength of 90 MPa or more and a Young's modulus of 3 GPa or more. The vehicle-mounted camera described in any one of [1] to [11].
[14] A method for manufacturing an in-vehicle camera according to any one of [1] to [13], comprising heating the primer layer and pressing the first resin member and the second resin member together so that the heated primer layer is interposed between the first resin member and the second resin member, thereby welding the first resin member and the second resin member.

According to the present disclosure, it is possible to provide an in-vehicle camera that can achieve excellent airtightness, 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 schematic diagram showing the components of the vehicle-mounted camera. FIG. 3 is a schematic diagram of the vehicle-mounted camera showing a combination of the various components of the vehicle-mounted camera. FIG. 4 is a schematic cross-sectional view showing a state in which one primer layer is laminated on a thermoplastic resin material in a first resin member of one embodiment. FIG. 5 is a schematic cross-sectional view showing a state in which a plurality of primer layers are laminated on a thermoplastic resin material in a first resin member according to another embodiment. FIG. 6 is a schematic cross-sectional view of the first resin member and the second resin member welded together.

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

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 through molecular diffusion-induced entanglement and crystallization by contact pressure and cooling.

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

[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 20.

Figure 2 is a schematic diagram showing each component of the vehicle-mounted camera 10, and Figure 3 is a schematic diagram of the vehicle-mounted camera showing the state in which each component of the vehicle-mounted camera 10 is combined. As shown in these figures, the vehicle-mounted camera 10 includes a housing X consisting of a first part 12, a second part 14, and a third part 16, and a module Y that is installed inside the housing X. Note that wiring and the like coming out of the module Y as shown in Figure 2 is omitted.

The first part 12 is a base and a member on which the module Y is placed. After the module Y is placed and fixed on the first part 12, the first to third parts 12, 14, and 16 are combined and joined so that the second part 14 and the third part 16 are placed over the first part 12 from above, thereby obtaining the housing X shown in Figure 3. The housing shown in Figure 3 has three interfaces formed by two of the three parts 12, 14, and 16, and the joining of these interfaces will be described in detail below.

For convenience, below, the second part 14 is also referred to as the "first resin member 1" and the third part 16 is also referred to as the "second resin member 4", but the present invention is not limited to such correspondences. In other words, the present invention includes all correspondences in which the "first resin member 1" is any one of the first part 12, the second part 14, and the third part 16, and the "second resin member 4" is any one of the first part 12, the second part 14, and the third part 16 that is different from the "first resin member 1". The same applies to the case where the housing X is made up of four or more parts.

[First resin member 1]
As shown in Fig. 4, the first resin member 1 of one embodiment is a laminate having a thermoplastic resin material 2 and one or more primer layers 3 laminated on the thermoplastic resin material. In Fig. 4, at least one of the primer layers 3 is an in situ polymerized composition layer 3a formed by polymerizing an in situ polymerized composition on the thermoplastic resin material 2.

In this disclosure, an in situ polymerization type composition refers to a composition that forms a thermoplastic structure, i.e., a linear polymer structure, by a combination of specific bifunctional compounds undergoing a polyaddition reaction in the presence of a catalyst on site, i.e., on various materials, or by a radical polymerization reaction of specific monofunctional monomers. Unlike curable resins that form a three-dimensional network due to a crosslinked structure when polymerized, in situ polymerization type compositions do not form a three-dimensional network due to a crosslinked structure and have thermoplastic properties.

The in-situ polymerization type composition layer 3a is preferably a layer formed from a composition containing an in-situ polymerization type phenoxy resin. The in-situ polymerization type phenoxy resin is also called a thermoplastic epoxy resin, an in-situ curing type phenoxy resin, an in-situ curing type epoxy resin, etc., and forms a thermoplastic structure, i.e., a linear polymer structure, by a polyaddition reaction between a bifunctional epoxy resin and a bifunctional phenolic compound in the presence of a catalyst.

In this disclosure, the primer layer 3 refers to a layer that is interposed between the thermoplastic resin material 2 of the first resin member 1 and the thermoplastic resin material of the second resin member 4, as shown in FIG. 6 described below, and that improves the bonding strength between the thermoplastic resin material 2 of the first resin member 1 and the thermoplastic resin material of the second resin member 4, when the thermoplastic resin material 2 of the first resin member 1 and the second resin member 4, which is the other object to be bonded, are bonded together to obtain an in-vehicle camera 10 (resin-resin bonded body).

According to the present disclosure, when the second resin member 4 has a thermoplastic resin material made of the same type of thermoplastic resin as the thermoplastic resin that constitutes the thermoplastic resin material 2, the first resin member 1 and the second resin member 4 can be firmly welded together. When the second resin member 4 has a thermoplastic resin material made of a thermoplastic resin different from the thermoplastic resin that constitutes the thermoplastic resin material 2, the SP values of the thermoplastic resin material 2 of the first resin member 1 and the thermoplastic resin material of the second resin member 4 are generally often far apart, but according to the present disclosure, such different types of thermoplastic resin materials can also be firmly welded together.

In this disclosure, "homogeneous thermoplastic resins" refers to thermoplastic resins in which the monomers constituting the thermoplastic resins are the same and the contents of the monomers are both 70% by mass or more. "Different thermoplastic resins" refers to thermoplastic resins other than "homogeneous thermoplastic resins", specifically thermoplastic resins that do not have a common monomer, thermoplastic resins in which the monomers constituting the thermoplastic resins are different in the maximum content, or thermoplastic resins in which the monomers constituting the maximum content are the same and at least one of the monomers constituting the maximum content is less than 70% by mass.

<Thermoplastic resin material 2>
The thermoplastic resin constituting the thermoplastic resin material 2 is not particularly limited.

Examples of thermoplastic resins include polypropylene (PP, SP value: 8.0 (J/cm ³ ) ^1/2 ), polyamide 6 (PA6, SP value: 12.7 to 13.6 (J/cm ³ ) ^1/2 ), polyamide 66 (PA66, SP value: 13.6 (J/cm ³ ) ^1/2 ), polyimide (PI), modified polyphenylene ether (m-PPE), polyphenylene sulfide (PPS, SP value: 19.8 (J/cm ³ ) ^1/2 ), polyetherimide (PEI), polycarbonate (PC, SP value: 9.7 (J/cm ³ ) ^1/2 ), polybutylene terephthalate (PBT, SP value: 20.5 (J/cm ³ ) ^1/2 ), and the like.

In this disclosure, the solubility parameter (SP value) is a value (δ) defined by regular solution theory introduced by Hildebrand that provides a numerical prediction of the degree of interaction between materials.

Various methods for calculating the SP value have been proposed. For example, the SP value can be calculated using the following formula (1) according to the method proposed by Fedors (Polym. Eng. Sci. 1974, Vol. 14, p. 147).
δ=(ΣE _coh /ΣV) ^1/2 (1)
Here, δ is the solubility parameter (J ^0.5 /cm ^1.5 ), E _coh is the cohesive energy density (J/mol), V is the molar volume (cm ³ /mol), and Σ means that these values given for each atomic group are summed up for all atomic groups constituting the monomer. The values of E _coh and V for each atomic group are listed, for example, in Table 7.3 of "Properties of Polymers, Third completely revised edition".

The thermoplastic resin material 2 may further include at least one selected from the group consisting of fillers and fibers. For example, the thermoplastic resin material 2 may be a high-rigidity type including the above-mentioned thermoplastic resin and at least one reinforcing material selected from the group consisting of talc, glass fiber, and carbon fiber. In an embodiment in which the thermoplastic resin is polypropylene, an example of the talc-containing polypropylene is TRC104N manufactured by SunAllomer Co., Ltd., an example of the glass fiber-containing polypropylene is PP-GF40-01 F02 manufactured by Daicel Miraize Co., Ltd., and an example of the carbon fiber-containing polypropylene is PP-CF40-11 F008 manufactured by Daicel Miraize Co., Ltd.

Thermoplastic resin material containing glass fiber is a type of glass fiber reinforced resin (GFRP), and thermoplastic resin material containing carbon fiber is a type of carbon fiber reinforced resin (CFRP). Thermoplastic resin material containing reinforcing fibers such as glass fiber and carbon fiber may be in the form of a molded body such as a sheet molding compound (SMC) or a bulk molding compound (BMC). SMC is a sheet-like molded body obtained by impregnating a resin composition containing a thermoplastic resin, a low shrinkage agent, a filler, etc., into reinforcing fibers such as glass fiber and carbon fiber.

<Primer layer 3>
The primer layer 3 is laminated on the thermoplastic resin material 2 .

[In situ polymerized composition layer 3a]
At least one layer of the primer layer 3 is an in-situ polymerized composition layer 3 a formed by polymerizing an in-situ polymerized composition on the thermoplastic resin material 2 .

The in-situ polymerization type composition layer 3a can be obtained by applying an in-situ polymerization type composition dissolved in a solvent to the surface of the thermoplastic resin material 2, penetrating the in-situ polymerization type composition into the surface layer of the thermoplastic resin material 2 swollen by the penetration of the solvent, volatilizing the solvent, and polymerizing the in-situ polymerization type composition. The in-situ polymerization type composition layer 3a can also be obtained by applying an emulsion containing the in-situ polymerization type composition or a powder coating containing the in-situ polymerization type composition onto the thermoplastic resin material 2, and polymerizing the in-situ polymerization type composition on the thermoplastic resin material 2. The in-situ polymerization type composition layer 3a can also be obtained by applying an in-situ polymerization type composition dissolved in a solvent onto a release film so that the film has a thickness of 1 to 100 μm after drying, leaving it in an environment of room temperature to 40 ° C. while volatilizing the solvent, slightly proceeding the reaction to B stage, placing the surface of the obtained film opposite to the release film on the thermoplastic resin material 2, peeling off the release film from the B staged film, and then performing a heating reaction at 40 to 150 ° C. for 1 to 30 minutes to polymerize the B staged film.

For powder paint, the B-staged film can be crushed and layered on the thermoplastic resin material 2 to a thickness of 1 to 100 μm, and can be used as is as a powder paint primer. For emulsion, the powder paint primer can be post-emulsified using an emulsifier, and then applied to the thermoplastic resin material 2 to a thickness of 1 to 100 μm, and can be used as an emulsion (water-based) primer.

The in-situ polymerized composition layer 3a preferably contains 50 to 100% by mass, and more preferably contains 70 to 100% by mass, of an in-situ polymerized resin produced by polymerizing the in-situ polymerized composition.

The in situ polymerization type composition preferably contains at least one of the following (1) to (7), more preferably contains the following (4), and further preferably contains a combination of a difunctional epoxy resin and a difunctional phenol compound.
(1) A combination of a bifunctional isocyanate compound and a diol. (2) A combination of a bifunctional isocyanate compound and a bifunctional amino compound. (3) A combination of a bifunctional isocyanate compound and a bifunctional thiol compound. (4) A combination of a bifunctional epoxy compound and a diol. (5) A combination of a bifunctional epoxy compound and a bifunctional carboxy compound. (6) A combination of a bifunctional epoxy compound and a bifunctional thiol compound. (7) A monofunctional radically polymerizable monomer.

The blend ratio of the bifunctional isocyanate compound and the diol in (1) is preferably set so that the molar equivalent ratio of isocyanate groups to hydroxyl groups is 0.7 to 1.5, more preferably 0.8 to 1.4, and even more preferably 0.9 to 1.3.

The blend ratio of the bifunctional isocyanate compound and the bifunctional amino compound in (2) is preferably set so that the molar equivalent ratio of isocyanate groups to amino groups is 0.7 to 1.5, more preferably 0.8 to 1.4, and even more preferably 0.9 to 1.3.

The blend ratio of the bifunctional isocyanate compound and the bifunctional thiol compound in (3) is preferably set so that the molar equivalent ratio of isocyanate groups to thiol groups is 0.7 to 1.5, more preferably 0.8 to 1.4, and even more preferably 0.9 to 1.3.

The mixing ratio of the bifunctional epoxy compound to the diol in (4) is preferably set so that the molar equivalent ratio of epoxy groups to hydroxyl groups is 0.7 to 1.5, more preferably 0.8 to 1.4, and even more preferably 0.9 to 1.3.

The mixing ratio of the bifunctional epoxy compound and the bifunctional carboxy compound in (5) is preferably set so that the molar equivalent ratio of epoxy groups to carboxy groups is 0.7 to 1.5, more preferably 0.8 to 1.4, and even more preferably 0.9 to 1.3.

The mixing ratio of the bifunctional epoxy compound and the bifunctional thiol compound in (6) is preferably set so that the molar equivalent ratio of epoxy groups to thiol groups is 0.7 to 1.5, more preferably 0.8 to 1.4, and even more preferably 0.9 to 1.3.

Examples of the in situ polymerization type composition include the following in situ polymerization type compositions (A) to (D).
In-situ polymerizable composition (A): A composition containing at least one of the above (1) to (7).
In-situ polymerization type composition (B): A composition containing at least one of the above (1) to (7) and maleic anhydride-modified polypropylene or modified polyphenylene ether.
In-situ polymerization type composition (C): A composition containing at least one of the above (1) to (7) and a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2.
In-situ polymerization type composition (D): A composition containing at least one of the above (1) to (7), maleic anhydride-modified polypropylene or modified polyphenylene ether, and a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2.

By laminating the in-situ polymerization type composition layer 3a as a primer layer 3 on the thermoplastic resin material 2, the thermoplastic resin material 2 can be firmly welded to the same type of thermoplastic resin material or to a different type of thermoplastic resin material. In particular, it is preferable that the in-situ polymerization type composition layer 3a is a layer that is in direct contact with the thermoplastic resin material 2.

As the in situ polymerization type composition, it is preferable to select a composition containing the same or similar thermoplastic resin as the thermoplastic resin constituting the thermoplastic resin material 2. For example, when the thermoplastic resin material 2 is a polyolefin, stronger welding can be achieved by using an in situ polymerization type composition containing maleic anhydride modified polyolefin. When the thermoplastic resin material 2 is a modified polyphenylene ether, stronger welding can be achieved by using an in situ polymerization type composition containing modified polyphenylene ether.

The primer layer 3 can also be composed of multiple layers including the in situ polymerized composition layer 3a. When the primer layer 3 is composed of multiple layers, it is preferable to laminate them so that the essential in situ polymerized composition layer 3a is the outermost surface on the side opposite the thermoplastic resin material 2. In this case, the in situ polymerized composition is polymerized not on the surface of the thermoplastic resin material 2, but on the surface of the layer directly below the in situ polymerized composition layer 3a.

(In situ polymerized composition layer A)
The in situ polymerizable composition layer A is formed from a polymer of the in situ polymerizable composition (A).

The in-situ polymerization type composition layer A can be obtained by subjecting a composition containing at least one of the above (1) to (6) to a polyaddition reaction in the presence of a catalyst. Suitable catalysts for the polyaddition reaction include, for example, tertiary amines such as triethylamine and 2,4,6-tris(dimethylaminomethyl)phenol, and phosphorus compounds such as triphenylphosphine. The polyaddition reaction is preferably carried out by heating at room temperature to 200°C for 5 to 120 minutes, depending on the composition of the composition.

Specifically, the in situ polymerization type composition layer A can be formed by dissolving a composition containing at least one of the above (1) to (6) in a solvent, applying the composition to the thermoplastic resin material 2, volatilizing the solvent as appropriate, and then heating to carry out a polyaddition reaction, thereby forming a more strongly bonded in situ polymerization type composition layer. The in situ polymerization type composition layer A can also be formed by placing a film of a B-staged composition containing at least one of the above (1) to (6) on the thermoplastic resin material 2, and heating the film to carry out a polyaddition reaction.

The in-situ polymerization type composition layer A can also be obtained by subjecting a composition containing the monofunctional radically polymerizable monomer of (7) to a radical polymerization reaction. The radical polymerization reaction is preferably carried out by heating at room temperature to 200°C for 5 to 90 minutes, depending on the composition of the composition. In the case of photocuring, the polymerization reaction is carried out by irradiating with ultraviolet light or visible light.

Specifically, the in situ polymerization type composition layer A can be formed by dissolving a composition containing the monofunctional radical polymerizable monomer of (7) in a solvent, applying the composition to the thermoplastic resin material 2, and then heating or irradiating with light to cause a radical polymerization reaction, thereby forming a more strongly bonded in situ polymerization type composition layer. The in situ polymerization type composition layer A can also be formed by placing a film of a B-staged composition containing the monofunctional radical polymerizable monomer of (7) on the thermoplastic resin material 2, and heating or irradiating the film to cause a radical polymerization reaction.

(Difunctional isocyanate compound)
The bifunctional isocyanate compound is a compound having two isocyanato groups, and examples thereof include diisocyanate compounds such as hexamethylene diisocyanate, tetramethylene diisocyanate, dimer acid diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI) or a mixture thereof, p-phenylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate (MDI), etc. From the viewpoint of the strength of the primer, TDI and MDI are preferred as the bifunctional isocyanate compound.

(Diol)
The diol is a compound having two hydroxy groups, and examples thereof include aliphatic glycols such as ethylene glycol, propylene glycol, diethylene glycol, and 1,6-hexanediol, and bisphenols such as bisphenol A, bisphenol F, and bisphenol S. From the viewpoint of the toughness of the primer, the diol is preferably propylene glycol or diethylene glycol.

(Bifunctional amino compound)
The bifunctional amino compound is a compound having two amino groups, and examples thereof include bifunctional aliphatic diamines and aromatic diamines. Examples of aliphatic diamines include ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-diaminobutane, 1,6-hexamethylenediamine, 2,5-dimethyl-2,5-hexanediamine, 2,2,4-trimethylhexamethylenediamine, isophoronediamine, bis(4-amino-3-methylcyclohexyl)methane, 1,3-diaminocyclohexane, and N-aminoethylpiperazine. Examples of aromatic diamines include diaminodiphenylmethane and diaminodiphenylpropane. From the viewpoint of the toughness of the primer, the bifunctional amino compound is preferably 1,3-propanediamine, 1,4-diaminobutane, or 1,6-hexamethylenediamine.

(Bifunctional thiol compound)
The bifunctional thiol compound is a compound having two mercapto groups in the molecule, and an example of the bifunctional secondary thiol compound is 1,4-bis(3-mercaptobutyryloxy)butane (for example, "Karenz MT (registered trademark) BD1" manufactured by Showa Denko K.K.).

(Difunctional epoxy compound)
The bifunctional epoxy compound is a compound having two epoxy groups in one molecule, and examples thereof include aromatic epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenol type epoxy resin, and naphthalene type bifunctional epoxy resin, and aliphatic epoxy compounds such as 1,6-hexanediol diglycidyl ether.

The bifunctional epoxy compounds may be used alone or in combination of two or more.

Specific examples include Mitsubishi Chemical Corporation's "jER (registered trademark) 828," "jER (registered trademark) 834," "jER (registered trademark) 1001," "jER (registered trademark) 1004," and "jER (registered trademark) YX-4000." Other bifunctional epoxy compounds with special structures can also be used.

(Bifunctional Carboxy Compound)
The bifunctional carboxy compound is a compound having two carboxy groups, and examples thereof include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, isophthalic acid, terephthalic acid, etc. From the viewpoint of the strength or toughness of the primer, the bifunctional carboxy compound is preferably isophthalic acid, terephthalic acid, or adipic acid.

(Monofunctional radically polymerizable monomer)
The monofunctional radical polymerizable monomer is a monomer having one ethylenically unsaturated bond. Examples include styrene monomers, α-, o-, m-, or p-alkyl, nitro, cyano, amide, or ester derivatives of styrene, chlorostyrene, vinyltoluene, and divinylbenzene; and (meth)acrylic acid esters such as ethyl (meth)acrylate, methyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofuryl (meth)acrylate, acetoacetoxyethyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, and glycidyl (meth)acrylate. The monofunctional radical polymerizable monomers may be used alone or in combination of two or more. From the viewpoint of strength or toughness of the primer, the monofunctional radical polymerizable monomer is preferably styrene, methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, phenoxyethyl (meth)acrylate, or a combination of two or more of these.

In order to sufficiently advance the radical polymerization reaction and form the desired in-situ polymerized composition layer, a solvent and, if necessary, additives such as a colorant may be included. In this case, it is preferable that the monofunctional radically polymerizable monomer is the main component among the components contained in the radically polymerizable composition other than the solvent. The main component means that the content of the monofunctional radically polymerizable monomer is 50 to 100 mass%. The content is preferably 60 mass% or more, more preferably 80 mass% or more.

As a polymerization initiator for a radical polymerization reaction, for example, a known organic peroxide, a photoinitiator, etc. may be suitably used. A room temperature radical polymerization initiator in which an organic peroxide is combined with a cobalt metal salt or an amine may be used. Examples of organic peroxides include those classified as ketone peroxides, peroxyketals, hydroperoxides, diallyl peroxides, diacyl peroxides, peroxyesters, or peroxydicarbonates. As a photoinitiator, it is desirable to use one that can initiate polymerization within the wavelength range from ultraviolet light to visible light.

The radical polymerization reaction is preferably carried out by heating at room temperature to 200°C for 5 to 90 minutes, depending on the type of reactive compound, etc. In the case of photocuring, the polymerization reaction is carried out by irradiating with ultraviolet light or visible light. Specifically, after the composition is applied, a radical polymerization reaction is carried out by heating or irradiating with light, whereby an in-situ polymerized composition layer can be formed from the radical polymerizable compound.

(In situ polymerized composition layer B)
The in situ polymerizable composition layer B is formed from a polymer of the in situ polymerizable composition (B).

The in-situ polymerization type composition layer B can be obtained by polyaddition reaction of at least one of the above (1) to (6) in the presence of a catalyst in a solution of maleic anhydride modified polypropylene or modified polyphenylene ether. As a catalyst for the polyaddition reaction, for example, tertiary amines such as triethylamine and 2,4,6-tris(dimethylaminomethyl)phenol, and phosphorus compounds such as triphenylphosphine are preferably used. The polyaddition reaction is preferably carried out by heating at room temperature to 200°C for 5 to 120 minutes, depending on the composition of the composition.

Specifically, the in-situ polymerization type composition layer B can be formed by dissolving in a solvent a composition containing maleic anhydride-modified polypropylene or modified polyphenylene ether and at least one of the above (1) to (6), applying the solution onto the thermoplastic resin material 2, volatilizing the solvent as appropriate, and then heating to carry out a polyaddition reaction. The in-situ polymerization type composition layer B can also be formed by placing a film of a B-stage mixture of maleic anhydride-modified polypropylene or modified polyphenylene ether and a composition containing at least one of the above (1) to (6) on the thermoplastic resin material 2, and heating the film to carry out a polyaddition reaction.

The in-situ polymerization type composition layer B can also be obtained by subjecting a composition containing the monofunctional radically polymerizable monomer of (7) above to a radical polymerization reaction in a solution of maleic anhydride-modified polypropylene or modified polyphenylene ether. The radical polymerization reaction is preferably carried out by heating at room temperature to 200°C for 5 to 90 minutes, depending on the composition of the composition. In the case of photocuring, the polymerization reaction is carried out by irradiating ultraviolet light or visible light.

Specifically, the in-situ polymerization type composition layer B can be formed by dissolving in a solvent a composition containing maleic anhydride-modified polypropylene or modified polyphenylene ether and the monofunctional radical polymerizable monomer of (7) above, applying the solution onto the thermoplastic resin material 2, and then heating or irradiating the solution with light to cause a radical polymerization reaction. The in-situ polymerization type composition layer B can also be formed by placing a film of a mixture of maleic anhydride-modified polypropylene or modified polyphenylene ether and the composition containing the monofunctional radical polymerizable monomer of (7) above, which has been B-staged, on the thermoplastic resin material 2, and heating or irradiating the film with light to cause a radical polymerization reaction.

(Maleic anhydride modified polypropylene)
The maleic anhydride-modified polypropylene is a polypropylene graft-modified with maleic anhydride. Examples of such polypropylene include Kayabrid 002PP, 002PP-NW, 003PP, and 003PP-NW manufactured by Kayaku Akzo Co., Ltd., and Modic series manufactured by Mitsubishi Chemical Corporation. SCONA TPPP2112GA, TPPP8112GA, or TPPP9212GA manufactured by BYK Co., Ltd. may be used in combination as a polypropylene additive functionalized with maleic anhydride.

(Modified polyphenylene ether)
The modified polyphenylene ether may be a known one, which is a blend of polyphenylene ether with polystyrene, polyamide, polyphenylene sulfide, polypropylene, or the like, and examples thereof include NORYL series (PPS/PS): 731, 7310, 731F, and 7310F manufactured by SABIC, ZYLON series (PPE/PS, PP/PPE, PA/PPE, PPS/PPE, and PPA/PPE) manufactured by Asahi Kasei Chemicals Corporation, and Epiace series and Lemalloy series (PPE/PS and PPE/PA) manufactured by Mitsubishi Engineering Plastics Corporation.

The total amount of (1) to (7) used in obtaining the in-situ polymerized composition layer B is preferably 5 to 100 parts by mass, more preferably 5 to 60 parts by mass, and even more preferably 20 to 40 parts by mass, based on 100 parts by mass of maleic anhydride modified polypropylene or modified polyphenylene ether.

(In situ polymerized composition layer C)
The in situ polymerizable composition layer C is formed from a polymer of the in situ polymerizable composition (C).

The in-situ polymerization type composition layer C can be obtained by subjecting at least one of the above (1) to (6) to a polyaddition reaction in the presence of a catalyst in a solution containing a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2. Suitable catalysts for the polyaddition reaction include, for example, tertiary amines such as triethylamine and 2,4,6-tris(dimethylaminomethyl)phenol, and phosphorus-based compounds such as triphenylphosphine. The polyaddition reaction is preferably carried out by heating at room temperature to 200°C for 5 to 120 minutes, depending on the composition of the composition.

Specifically, the in-situ polymerization type composition layer C can be formed by dissolving in a solvent a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2 and a composition containing at least one of the above (1) to (6), applying the solution onto the thermoplastic resin material 2, volatilizing the solvent as appropriate, and then heating to carry out a polyaddition reaction. The in-situ polymerization type composition layer C can also be formed by placing a film of a B-stage mixture of a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2 and a composition containing at least one of the above (1) to (6) on the thermoplastic resin material 2, and heating the film to carry out a polyaddition reaction.

The in-situ polymerization type composition layer C can also be obtained by subjecting a composition containing the monofunctional radically polymerizable monomer of (7) above to a radical polymerization reaction in a solution containing a thermoplastic resin of a different type to the thermoplastic resin constituting the thermoplastic resin material 2. The radical polymerization reaction is preferably carried out by heating at room temperature to 200°C for 5 to 90 minutes, depending on the composition of the composition. In the case of photocuring, the polymerization reaction is carried out by irradiating with ultraviolet light or visible light.

Specifically, the in-situ polymerization type composition layer C can be formed by dissolving a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2 and a composition containing the monofunctional radical polymerizable monomer of (7) in a solvent, applying the solution onto the thermoplastic resin material 2, and then heating or irradiating with light to cause a radical polymerization reaction. The in-situ polymerization type composition layer C can also be formed by placing a film of a mixture of a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2 and a composition containing the monofunctional radical polymerizable monomer of (7) in a B-stage on the thermoplastic resin material 2, and heating or irradiating the film to cause a radical polymerization reaction.

(In situ polymerized composition layer D)
The in situ polymerizable composition layer D is formed from a polymer of the in situ polymerizable composition (D).

The in-situ polymerization type composition layer D can be obtained by polyaddition reaction of at least one of the above (1) to (6) in the presence of a catalyst in a solution of maleic anhydride-modified polypropylene or modified polyphenylene ether, and then mixing with a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2. It can also be obtained by polyaddition reaction of at least one of the above (1) to (6) in the presence of a catalyst in a solution containing a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2, and then mixing with maleic anhydride-modified polypropylene or modified polyphenylene ether. It can also be obtained by polyaddition reaction of at least one of the above (1) to (6) in the presence of a catalyst with maleic anhydride-modified polypropylene or modified polyphenylene ether, a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2, and a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2. As a catalyst for the polyaddition reaction, for example, tertiary amines such as triethylamine and 2,4,6-tris(dimethylaminomethyl)phenol, and phosphorus-based compounds such as triphenylphosphine are preferably used. The polyaddition reaction is preferably carried out by heating at room temperature to 200° C. for 5 to 120 minutes, although this depends on the composition of the composition.

Specifically, the in-situ polymerization type composition layer D can be formed by dissolving in a solvent a maleic anhydride-modified polypropylene or modified polyphenylene ether, a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2, and a composition containing at least one of the above (1) to (6), applying the solution onto the thermoplastic resin material 2, volatilizing the solvent appropriately, and then heating to carry out a polyaddition reaction. The in-situ polymerization type composition layer D can also be formed by placing a film of a B-stage mixture of maleic anhydride-modified polypropylene or modified polyphenylene ether, a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2, and a composition containing at least one of the above (1) to (6) on the thermoplastic resin material 2, and heating the film to carry out a polyaddition reaction.

The in-situ polymerization type composition layer D can also be obtained by subjecting a composition containing the monofunctional radically polymerizable monomer of (7) to a radical polymerization reaction in a solution containing maleic anhydride modified polypropylene or modified polyphenylene ether and a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2. The radical polymerization reaction is preferably carried out by heating at room temperature to 200°C for 5 to 90 minutes, depending on the composition of the composition. In the case of photocuring, the polymerization reaction is carried out by irradiating ultraviolet light or visible light.

Specifically, the in-situ polymerization type composition layer D can be formed by dissolving in a solvent a composition containing maleic anhydride-modified polypropylene or modified polyphenylene ether, a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2, and the monofunctional radical polymerizable monomer (7) described above, and then applying the solution to the thermoplastic resin material 2, and then heating or irradiating the solution with light to cause a radical polymerization reaction. The in-situ polymerization type composition layer D can also be formed by placing a film of a mixture of maleic anhydride-modified polypropylene or modified polyphenylene ether, a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material 2, and a composition containing the monofunctional radical polymerizable monomer (7) described above in a B-stage on the thermoplastic resin material 2, and heating or irradiating the film with light to cause a radical polymerization reaction.

The manner of reaction that occurs when forming the in-situ polymerization type composition layer is diverse, such as the reaction of maleic anhydride-modified polypropylene or modified polyphenylene ether with a bifunctional epoxy resin, and the reaction of maleic anhydride-modified polypropylene or modified polyphenylene ether with a bifunctional phenol compound, and it is not possible to comprehensively express specific aspects based on the combinations. Therefore, it is impossible or impractical to directly identify the in-situ polymerization type composition layer by its structure or properties.

[Curable resin layer 3b]
When the primer layer 3 is composed of multiple layers including the in-situ polymerization type composition layer 3a, as shown in FIG. 5, the primer layer 3 may also include a curable resin layer 3b formed from a composition containing a curable resin between the in-situ polymerization type composition layer 3a and the thermoplastic resin material 2.

The composition containing the curable resin may contain a solvent and, if necessary, an additive such as a colorant, in order to sufficiently proceed with the curing reaction of the curable resin and form the desired curable resin layer. In this case, it is preferable that the curable resin is the main component among the components contained in the composition other than the solvent. The main component means that the content of the curable resin is 40 to 100 mass%. The content is preferably 60 mass% or more, more preferably 70 mass% or more, and even more preferably 80 mass% or more.

Examples of the curable resin include urethane resin, epoxy resin, vinyl ester resin, and unsaturated polyester resin.

The curable resin layer 3b may be formed of one of these resins, or may be formed by mixing two or more of them. The curable resin layer 3b may be composed of multiple layers, and each layer may be formed of a composition containing a different type of curable resin.

The coating method for forming the curable resin layer 3b using a composition containing the curable resin monomer is not particularly limited, but examples include a spray coating method, a dipping method, etc.

In this disclosure, curable resin broadly 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. The light-curing types can be cured in a short time by irradiation with visible light or ultraviolet light. The light-curing types may be used in combination with heat-curing types and/or room temperature curing types. Examples of the light-curing types include vinyl ester resins such as "Lipoxy (registered trademark) LC-760" and "Lipoxy (registered trademark) LC-720" manufactured by Showa Denko K.K.

(urethane resin)
The urethane resin is usually a resin obtained by reacting an isocyanato group of an isocyanate compound with a hydroxyl group of a polyol compound, 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 (those that cure by oxidative polymerization of unsaturated fatty acid groups), moisture-curing types (those that cure by reaction between isocyanato groups and water in the air), block types (those that cure by reaction between the regenerated isocyanato groups and hydroxyl groups after the blocking agent is dissociated by heating), and lacquer types (those that cure by evaporation of the solvent and drying). Of these, moisture-curing one-component urethane resins are preferred from the standpoint of ease of handling. A specific example is "UM-50P" manufactured by Showa Denko K.K.

Examples of two-component urethane resins include 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 the polyol curing type include polyester polyols, polyether polyols, phenolic resins, etc.

Examples of isocyanate compounds having an isocyanate 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 polymeric MDI, which is a polynuclear mixture thereof; and alicyclic isocyanates such as isophorone diisocyanate (IPDI).

It is preferable that the compounding ratio of the polyol compound to the isocyanate compound in the polyol-curing type two-component urethane resin is such that the molar equivalent ratio of hydroxyl groups/isocyanato groups is in the range of 0.7 to 1.5.

Examples of urethane catalysts used in the two-component urethane resin 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 polyol curing type, it is generally preferable to mix 0.01 to 10 parts by mass of the urethane catalyst per 100 parts by mass of the polyol compound.

(Epoxy resin)
The epoxy resin is a resin having at least two epoxy groups in one molecule. Examples of the prepolymer of the epoxy resin before curing include ether-based bisphenol-type epoxy resin, novolac-type epoxy resin, polyphenol-type epoxy resin, aliphatic-type epoxy resin, ester-based aromatic epoxy resin, cyclic aliphatic epoxy resin, and ether-ester-based epoxy resin. Among these, bisphenol A-type epoxy resin is preferably used. The epoxy resin may be used alone or in combination of two or more kinds.

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

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

Examples of the curing agent used for the epoxy resin include known curing agents such as aliphatic amines, aromatic amines, acid anhydrides, phenolic resins, thiols, imidazoles, and cationic catalysts. By using the curing agent in combination with a long-chain aliphatic amine and/or thiols, a curable resin layer having a large elongation rate and excellent impact resistance can be formed.

Specific examples of the thiols include the same compounds as those exemplified as thiol compounds for forming the functional group-containing layer described below. Among these, pentaerythritol tetrakis(3-mercaptobutyrate) (for example, 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 curable resin layer.

(Vinyl ester resin)
The vinyl ester resin is a compound obtained by dissolving a vinyl ester compound in a polymerizable monomer (e.g., styrene, etc.). It is also called an epoxy (meth)acrylate resin, but in the present disclosure, the vinyl ester resin also includes a urethane (meth)acrylate resin.

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

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

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

The organic peroxide is not particularly limited, but examples thereof include ketone peroxides, peroxyketals, hydroperoxides, diallyl peroxides, diacyl peroxides, peroxy esters, peroxydicarbonates, etc. By combining these 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 a condensation product (unsaturated polyester) obtained by an esterification reaction between a polyol compound and an unsaturated polybasic acid (and, if necessary, a saturated polybasic acid) in a polymerizable monomer (e.g., styrene, etc.).

As the unsaturated polyester resin, those described in "Polyester Resin Handbook" (published by Nikkan Kogyo Shimbun, 1988) and "Paint Terminology Dictionary" (published by Shikizai Kyokai, 1993) can also be used. Specific examples include "Rigolac (registered trademark)" manufactured by Showa Denko K.K.

The unsaturated polyester resin can be cured by radical polymerization through heating in the presence of a catalyst similar to that of the vinyl ester resin.

[Function of primer layer 3]
The primer layer 3 is formed on the surface of the thermoplastic resin material 2 or on the surface and surface layer of the thermoplastic resin material 2 .

The primer layer 3 on the surface of the thermoplastic resin material 2 means that the composition that forms the primer layer 3 is dissolved in a solvent and applied to the surface of the thermoplastic resin material 2, and the solvent is then volatilized on the surface of the thermoplastic resin material 2 to form the primer layer 3.

The primer layer 3 on the surface of the thermoplastic resin material 2 means that the composition forming the primer layer 3 is dissolved in a solvent and applied to the surface of the thermoplastic resin material 2, the composition forming the primer layer 3 is allowed to penetrate into the surface of the thermoplastic resin material 2 which has swelled due to the penetration of the solvent, and the solvent is then volatilized to form the primer layer.

The primer layer 3 can provide excellent bonding with the second resin member 4 to be bonded. It is also possible to obtain a first resin member 1 that can maintain the bonding property over a long period of time, such as several months. The primer layer 3 also protects the surface of the thermoplastic resin material 2, and can suppress deterioration such as adhesion of dirt and oxidation.

[Second resin member 4]
The thermoplastic resin constituting the thermoplastic resin material of the second resin member 4 may be the same type as or different from the thermoplastic resin constituting the thermoplastic resin material 2 of the first resin member 1. From the viewpoint of strong welding, it is preferable that these thermoplastic resins are the same type.

When attempting to join two thermoplastic resin materials, even if the thermoplastic resin constituting one thermoplastic resin material and the thermoplastic resin constituting the other thermoplastic resin material are of the same type, if one or both of the thermoplastic resins contain fillers or fibers, or if the thermoplastic resin is a blend with another thermoplastic resin, the bonding strength between the two thermoplastic resin materials may be insufficient according to conventional techniques. According to the present disclosure, even in these cases, the first resin member 1 and the second resin member 4 can be firmly welded together via the primer layer 3 (contained in the first resin member 1).

When the thermoplastic resin constituting the thermoplastic resin material 2 of the first resin member 1 and the thermoplastic resin constituting the thermoplastic resin material of the second resin member 4 are of the same type, the proportion of the monomer that occupies the maximum content among the monomers constituting the thermoplastic resin is 70 mass% or more in each case, preferably 70 to 100 mass%, more preferably 80 to 100 mass%, and even more preferably 85 to 100 mass%.

When the thermoplastic resin material 2 of the first resin member 1 and/or the thermoplastic resin material of the second resin member 4 contains at least one type selected from the group consisting of fillers and fibers, the content is preferably 5 to 50 mass%, more preferably 5 to 40 mass%, and even more preferably 5 to 30 mass%. When the content is within the above range, the bonding strength between the first resin member 1 and the second resin member 4 can be increased.

When the thermoplastic resin constituting the thermoplastic resin material 2 of the first resin member 1 and/or the thermoplastic resin constituting the thermoplastic resin material of the second resin member 4 is a blend of a primary thermoplastic resin and a secondary thermoplastic resin, the content of the secondary thermoplastic resin is preferably 5 to 40 mass%, more preferably 5 to 30 mass%, and even more preferably 5 to 20 mass%. When the content is within the above range, the bonding strength between the first resin member 1 and the second resin member 4 can be increased.

The content can be calculated by the following formula.
Content (mass%)=[B/(A+B)]×100
(In the formula, A is the mass (g) of the main thermoplastic resin among the thermoplastic resin constituting the thermoplastic resin material 2 of the first resin member 1 and/or the thermoplastic resin constituting the thermoplastic resin material of the second resin member 4, and B is the mass (g) of the secondary thermoplastic resin among the thermoplastic resin constituting the thermoplastic resin material 2 of the first resin member 1 and/or the thermoplastic resin constituting the thermoplastic resin material of the second resin member 4.)

According to the present disclosure, even if the thermoplastic resin constituting the thermoplastic resin material of the second resin member 4 and the thermoplastic resin constituting the thermoplastic resin material 2 of the first resin member 1 are different types, the second resin member 4 and the first resin member 1 can be firmly welded together. Furthermore, even if the SP value of the thermoplastic resin constituting the thermoplastic resin material of the second resin member 4 and the SP value of the thermoplastic resin constituting the thermoplastic resin material 2 of the first resin member 1 are different, the second resin member 4 and the first resin member 1 can be firmly welded together.

[In-vehicle camera 10 (resin-resin bonded body)]
Fig. 6 is a schematic cross-sectional view of the first resin member 1 and the second resin member 4 welded together, and is a diagram showing, for example, the circled portion A in Fig. 3. The vehicle-mounted camera 10 (resin-resin bonded body) is formed by welding the first resin member 1 and the second resin member 4 together with the primer layer 3 interposed therebetween.

As shown in Figure 6, in the vehicle-mounted camera 10, the thermoplastic resin material of the third part 4 (16) and the thermoplastic resin material 2 of the second part 1 (14) are welded together via a primer layer 3 (included in the second part 14).

In the vehicle-mounted camera 10 of this embodiment, when the parts 12 to 16 that make up the housing X are assembled and joined, they are joined by welding via a primer layer rather than using mechanical joining methods such as screwing, so that excellent airtightness can be achieved. Also, unlike when the parts of the housing X that are molded separately are bonded using an adhesive, the vehicle-mounted camera 10 of this embodiment can be manufactured inexpensively because it 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.).

As a result, this embodiment can provide an in-vehicle camera that can achieve excellent airtightness, and such an in-vehicle camera can be manufactured inexpensively.

The joining by welding via a primer layer in this embodiment can be applied to at least one of the interfaces of each of the parts 12 to 16 that make up the housing X (the interface between member 12 and member 14, the interface between member 14 and member 16, and the interface between member 16 and member 12), but is not intended to be applied to all interfaces.

It is preferable that the thermoplastic resin material of the first resin member 1 or the second resin member 4 contains polypropylene and at least one reinforcing material selected from the group consisting of talc, glass fiber, and carbon fiber, and that the first resin member 1 or the second resin member 4 has a tensile strength of 40 MPa or more and a Young's modulus of 3 GPa or more.

It is preferable that the thermoplastic resin material of the first resin member 1 or the second resin member 4 contains polyetherimide and at least one reinforcing material selected from the group consisting of talc, glass fiber, and carbon fiber, and that the first resin member 1 or the second resin member 4 has a tensile strength of 90 MPa or more and a Young's modulus of 3 GPa or more.

The thickness (thickness after drying) of the primer layer 3 depends on the materials of the first resin member 1 and the second resin member 4 and the contact area of the joint, but from the viewpoint of obtaining excellent joint strength, it is preferably 1 μm to 500 μm, more preferably 3 μm to 100 μm, and even more preferably 5 μm to 70 μm. The thickness (thickness after drying) of the in-situ polymerized composition layer 3a is preferably 1 to 60 μm. When the primer layer 3 is a multi-layer structure, the thickness (thickness after drying) of the primer layer 3 is the total thickness of each layer.

Methods for manufacturing the vehicle-mounted camera 10 (resin-resin bonded body) include a method in which the second resin member 4 is welded to the primer layer 3 of the first resin member 1 by at least one method selected from the group consisting of ultrasonic welding, vibration welding, electromagnetic induction, high frequency, hot plate welding, laser, and heat pressing, and a method in which a thermoplastic resin material of the second resin member 4 is molded by injection molding onto the primer layer 3 of the first resin member 1.

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 (resin-resin bonded body) by a heat press method. Specifically, the vehicle-mounted camera 10 (resin-resin bonded body) can be manufactured by heating the primer layer 3 and pressing the first resin member 1 and the second resin member 4 together so that the heated primer layer 3 is interposed between the first resin member 1 and the second resin member 4. The heating temperature of the primer layer depends on the melting point and 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. In addition, the heating temperature of a primer layer having a melting point is preferably set to the melting point ±5°C, and the heating temperature of a primer layer having a softening point is preferably set to the softening point ±15°C. The pressure during pressing is preferably 0.01 MPa to 10 MPa.

In another embodiment, the second resin member 4, rather than the first resin member 1, may have one or more primer layers laminated to the thermoplastic resin material. The primer layer 3' of the second resin member 4 may be the same as the primer layer 3 described above. In this embodiment, the welding of the first resin member 1 and the second resin member 4 can be carried out by replacing the above-mentioned "first resin member 1" with the "second resin member 4" in this embodiment, and replacing the above-mentioned "second resin member 4" with the "first resin member 1" in this embodiment.

In yet another embodiment, both the first resin member 1 and the second resin member 4 have the above-mentioned primer layers 3, 3', and the primer layer 3 of the first resin member 1 and the primer layer 3' of the second resin member 4 are welded together. In this embodiment, the thermoplastic resin constituting the thermoplastic resin material 2 of the first resin member 1 and the thermoplastic resin constituting the thermoplastic resin material of the second resin member 4 may be the same type or different types. In this embodiment, the vehicle-mounted camera 10 (resin-resin bonded body) can be manufactured by welding the primer layer 3 of the first resin member 1 and the primer layer 3' of the second resin member 4 together using at least one method selected from the group consisting of ultrasonic welding, vibration welding, electromagnetic induction, high frequency, laser, and heat pressing, preferably heat pressing.

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

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

<Thermoplastic resin material for test specimens>
Using an injection molding machine (SE100V manufactured by Sumitomo Heavy Industries, Ltd.) under the conditions shown in Table 1 below, thermoplastic resin materials for test pieces for tensile tests (width 10 mm, length 45 mm, thickness 3 mm): talc-containing PP resin, glass fiber-containing PA6 resin, glass fiber-containing PA66 resin, m-PPE resin, PPS resin, PEI resin, PC resin, and glass fiber-containing PBT resin were obtained.

<Preparation of Test Pieces: Experimental Test Examples 1 to 3, and Comparative Test Example 1>
(Preparation of in situ polymerizable composition-1 for forming primer layer)
A bifunctional epoxy resin (jER (registered trademark) 1001 manufactured by Mitsubishi Chemical Corporation) (bisphenol A type epoxy resin, molecular weight about 900): 100 g, bisphenol S: 6.2 g, and triethylamine: 0.4 g were dissolved in toluene 197 g to obtain an in-situ polymerization type composition-1 (an in-situ polymerization type thermoplastic epoxy resin composition).

(Formation of primer layer)
Next, the in situ polymerization composition-1 was applied by spraying to one surface of the thermoplastic resin material for test specimens, PBT, PC, PEI, or PPS, so that the thickness after drying would be 80 μm. The solvent (toluene) was evaporated by leaving it in the air at room temperature for 30 minutes, and then the mixture was left in a furnace at 150° C. for 30 minutes to carry out a polyaddition reaction, and then cooled to room temperature to obtain test specimens PBT-1, PC-1, PEI-1, and PPS-1 having a thermoplastic epoxy resin as a primer layer.

Hereinafter, the surface of the test piece on which a primer layer is formed will be referred to as the primer surface, and the surface on which a primer layer is not formed will be referred to as the primer-free surface. In addition, in Tables 2 to 4 and 6 below, the surface with a primer layer will be indicated as (present), and the surface without a primer layer will be indicated as (absent).

<Test Example 1>
(Welding)
The primer surface of PPS-1 and the primer surface of PEI-1 were overlapped with each other so that the joint had an overlap length of 5 mm and a width of 10 mm, and then ultrasonically welded using an ultrasonic welding machine SONOPET-JII430T-M (28.5 KHz) manufactured by Seidensha Denshi Kogyo Co., Ltd. to obtain a test piece 1 (resin-resin joint). The joint here means the location where the thermoplastic resin materials for the test piece were overlapped.

(tensile shear strength)
After leaving the test piece 1 at room temperature for one day, a tensile shear strength test was performed in accordance with ISO19095 1-4 using a tensile tester (Shimadzu Corporation universal testing machine autograph "AG-IS", load cell 10 kN, tensile speed 10 mm/min, temperature 23°C, 50% RH) to measure the bonding strength. The measurement results are shown in Table 2 below.

<Test Example 2>
(Welding)
The primer surface of PBT-1 and the primer surface of PC-1 were ultrasonically welded together in the same manner as in Experimental Test Example 1 to obtain a test piece 2 (resin-resin bonded body).

(tensile shear strength)
A tensile shear strength test was carried out on the test piece 2 in the same manner as in Example Test 1. The measurement results are shown in Table 2 below.

<Test Example 3>
(Welding)
The primer surface of PBT-1 and the primer-free surface of PC-1 were ultrasonically welded together in the same manner as in Experimental Test Example 1 to obtain a test piece 3 (resin-resin bonded body).

(tensile shear strength)
A tensile shear strength test was carried out on the test piece 3 in the same manner as in Example Test 1. The measurement results are shown in Table 2 below.

<Test Example 4>
(Welding)
The primer surface of PBT-1 and the primer-free surface of PPS-1 were ultrasonically welded together in the same manner as in Example 1 to obtain a test piece 4 (resin-resin bonded body).

(tensile shear strength)
A tensile shear strength test was carried out on the test piece 4 in the same manner as in Example Test 1. The measurement results are shown in Table 2 below.

Comparative Test Example 1
An attempt was made to ultrasonically weld the primer-free surface of PBT-1 and the primer-free surface of PPS-1 in the same manner as in Experimental Test 1, but welding was not possible.

<Preparation of Test Pieces: Experimental Test Examples 5 to 7, and Comparative Test Examples 2 to 3>
(Preparation of in situ polymerizable composition-2 for forming primer layer)
Diphenylmethane diisocyanate (Millionate MT, manufactured by Tosoh Corporation): 100 g, propylene glycol: 54.7 g, and 4,4'-diaminodiphenylmethane: 15.8 g were dissolved in 287 g of acetone to obtain an in situ polymerization type composition-2 (in situ polymerization type urethane resin composition).

(Formation of primer layer)
Next, the in situ polymerization type composition-2 was applied by spraying to one surface of the thermoplastic resin material for the test specimen, PA6, PA66, PBT, or PC, so that the thickness after drying was 90 μm. The solvent (acetone) was evaporated by leaving it in the air at room temperature for 30 minutes, and then the mixture was left in a furnace at 150° C. for 30 minutes to carry out a polyaddition reaction, and then cooled to room temperature to obtain test specimens PA6-1, PA66-1, PBT-2, and PC-2, each having a primer layer of urethane resin.

<Test Example 5>
(Welding)
The primer surface of PA6-1 and the primer surface of PBT-2 were overlapped with each other so that the joint overlapped length was 5 mm and width was 10 mm, and in this state, ultrasonic welding was performed using an ultrasonic welding machine SONOPET-JII430T-M (28.5 KHz) manufactured by Seidensha Denshi Kogyo Co., Ltd., to obtain a test piece 5 (resin-resin joint).

(tensile shear strength)
The tensile shear strength test was carried out on the test piece 5 in the same manner as in the practical test example 1 to measure the bonding strength. The measurement results are shown in Table 3 below.

<Test Examples 6 and 7>
In the same manner as in Example Test 5, test pieces were prepared and tensile shear strength tests were carried out in the combinations shown in Table 3 below. The results are shown in Table 3 below.

Comparative Test Example 2
An attempt was made to ultrasonically weld the primer-free surface of PA6-1 and the primer-free surface of PBT-2 in the same manner as in Experimental Test Example 5, but welding was not possible.

Comparative Test Example 3
An attempt was made to ultrasonically weld the primer-free surface of PA66-1 and the primer-free surface of PC-2 in the same manner as in Experimental Test Example 5, but welding was not possible.

<Test pieces: Experimental test examples 8 to 10, and comparative test examples 4 to 5>
(Preparation of in situ polymerizable composition-3 for forming primer layer)
5 g of maleic anhydride-modified polypropylene (Modic (registered trademark) ER321P manufactured by Mitsubishi Chemical Corporation), 1.01 g of epoxy resin (jER (registered trademark) 1001 manufactured by Mitsubishi Chemical Corporation), and 0.24 g of bisphenol A were dissolved in 95 g of hot xylene, and then 0.006 g of 2,4,6-tris(dimethylaminomethyl)phenol was added thereto and the mixture was quenched to obtain in situ polymerization type composition-3 (in situ polymerization type maleic anhydride-containing epoxy resin composition).

(Preparation of in situ polymerizable composition-4 for forming primer layer)
3.77 g of modified polyphenylene ether (NOLYL731 manufactured by SABIC Corporation), 1.0 g of bifunctional epoxy resin (jER (registered trademark) 1001 manufactured by Mitsubishi Chemical Corporation), and 0.22 g of bisphenol A were dissolved in 95 g of hot xylene, and then 0.005 g of 2,4,6-tris(dimethylaminomethyl)phenol was added thereto and the mixture was quenched to obtain an in situ polymerization type composition-4 (an in situ polymerization type modified polyphenylene ether-containing epoxy resin composition).

(Formation of primer layer)
Next, the in situ polymerization type composition-3 was sprayed onto one surface of the thermoplastic resin material for test pieces, PP (talc 30 mass%) or PBT, so that the thickness after drying would be 80 μm. The solvent (xylene) was evaporated by leaving it in the air at room temperature for 30 minutes, and then the mixture was left in a furnace at 150° C. for 30 minutes to carry out a polyaddition reaction, and then cooled to room temperature to obtain test pieces PP-1 and PBT-3 having a maleic anhydride-containing thermoplastic epoxy resin as a primer layer.

Next, the in situ polymerizable composition-4 was sprayed onto one surface of the thermoplastic resin material m-PPE for the test specimen so that the thickness after drying would be 80 μm. The specimen was then left in air at room temperature for 30 minutes to volatilize the solvent (xylene), and then left in a 150°C oven for 30 minutes to carry out a polyaddition reaction. It was then allowed to cool to room temperature to obtain test specimen m-PPE-1, with the modified polyphenylene ether-containing epoxy resin as the primer layer.

<Test Example 8>
(Welding)
The primer surface of PP-1 and the primer surface of m-PPE-1 were overlapped with each other so that the joints had an overlapping length of 5 mm and a width of 10 mm, and then ultrasonically welded using an ultrasonic welding machine SONOPET-JII430T-M (28.5 KHz) manufactured by Seidensha Denshi Kogyo Co., Ltd. to obtain a test piece 8 (resin-resin joint).

(tensile shear strength)
The test piece 8 was subjected to a tensile shear strength test in the same manner as in Example Test 1 to measure the bonding strength. The measurement results are shown in Table 4 below.

<Test Examples 9 and 10>
In the same manner as in Example Test 8, test pieces were prepared in the combinations shown in Table 4 below, and tensile shear strength tests were performed. The results are shown in Table 4 below.

Comparative Test Example 4
An attempt was made to ultrasonically weld the primer-free surface of PP-1 and the primer-free surface of PBT-3 in the same manner as in Example 8, but welding was not possible.

Comparative Test Example 5
An attempt was made to ultrasonically weld the primer-free surface of m-PPE-1 to one surface (primer-free surface) of the PC thermoplastic resin material for the test piece in the same manner as in Example 8, but welding was not possible.

<Test Piece: Test Example 11>
Primer-attached thermoplastic resin materials PC-1, PBT-1, PEI-1, PPS-1, PA6-1, PA66-1, m-PPE-1, or PP-1 were inserted into an injection molding die, and the different thermoplastic resins listed in Table 5 were injection molded onto the primer surfaces under the same conditions as those in Table 1. Test pieces (8 types) were obtained in which the joints between the primer surfaces and the injection-molded thermoplastic resins overlapped to a length of 5 mm and a width of 10 mm.

(tensile shear strength)
A tensile shear strength test was carried out on each test piece in the same manner as in Example Test 1. The measurement results are shown in Table 5 below.

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

Reference Signs List 1 First resin member 2 Thermoplastic resin material 3 Primer layer 3a In-situ polymerization type composition layer 3b Curable resin layer 4 Second resin member 10 Vehicle-mounted camera (resin-resin bonded body)
12 First part 14 Second part 16 Third part 20 Bracket A Circled part X Housing Y Module

Claims (14)

a first resin member having a thermoplastic resin material;
a second resin member having a thermoplastic resin material;
A vehicle-mounted camera comprising one or more primer layers laminated on at least one of the thermoplastic resin material of the first resin member and the thermoplastic resin material of the second resin member,
The vehicle-mounted camera includes a housing having at least a first part and a second part, and at least one module housed in the housing;
the first resin member is one of the first part and the second part,
the second resin member is the other of the first part and the second part,
the first resin member and the second resin member are welded together via the primer layer,
At least one of the primer layers is an in-situ polymerizable composition layer formed by polymerizing an in-situ polymerizable composition on the thermoplastic resin material. The vehicle-mounted camera according to claim 1, wherein the in-situ polymerized composition layer is a layer that is in direct contact with the thermoplastic resin material. The vehicle-mounted camera according to claim 1 or 2, wherein the in-situ polymerization type composition contains at least one of the following (1) to (7).
(1) A combination of a bifunctional isocyanate compound and a diol. (2) A combination of a bifunctional isocyanate compound and a bifunctional amino compound. (3) A combination of a bifunctional isocyanate compound and a bifunctional thiol compound. (4) A combination of a bifunctional epoxy compound and a diol. (5) A combination of a bifunctional epoxy compound and a bifunctional carboxy compound. (6) A combination of a bifunctional epoxy compound and a bifunctional thiol compound. (7) A monofunctional radically polymerizable monomer. The in-situ polymerization type composition is a composition containing at least one of the following (1) to (7) and maleic anhydride modified polypropylene or modified polyphenylene ether. The vehicle-mounted camera according to any one of claims 1 to 2.
(1) A combination of a bifunctional isocyanate compound and a diol. (2) A combination of a bifunctional isocyanate compound and a bifunctional amino compound. (3) A combination of a bifunctional isocyanate compound and a bifunctional thiol compound. (4) A combination of a bifunctional epoxy compound and a diol. (5) A combination of a bifunctional epoxy compound and a bifunctional carboxy compound. (6) A combination of a bifunctional epoxy compound and a bifunctional thiol compound. (7) A monofunctional radically polymerizable monomer. The in-situ polymerization type composition is a composition containing at least one of the following (1) to (7) and a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material. The vehicle-mounted camera according to any one of claims 1 to 2.
(1) A combination of a bifunctional isocyanate compound and a diol. (2) A combination of a bifunctional isocyanate compound and a bifunctional amino compound. (3) A combination of a bifunctional isocyanate compound and a bifunctional thiol compound. (4) A combination of a bifunctional epoxy compound and a diol. (5) A combination of a bifunctional epoxy compound and a bifunctional carboxy compound. (6) A combination of a bifunctional epoxy compound and a bifunctional thiol compound. (7) A monofunctional radically polymerizable monomer. The in-situ polymerization type composition is a composition containing at least one of the following (1) to (7), maleic anhydride-modified polypropylene or modified polyphenylene ether, and a thermoplastic resin different from the thermoplastic resin constituting the thermoplastic resin material. The vehicle-mounted camera according to any one of claims 1 and 2.
(1) A combination of a bifunctional isocyanate compound and a diol. (2) A combination of a bifunctional isocyanate compound and a bifunctional amino compound. (3) A combination of a bifunctional isocyanate compound and a bifunctional thiol compound. (4) A combination of a bifunctional epoxy compound and a diol. (5) A combination of a bifunctional epoxy compound and a bifunctional carboxy compound. (6) A combination of a bifunctional epoxy compound and a bifunctional thiol compound. (7) A monofunctional radically polymerizable monomer. The vehicle-mounted camera described in any one of claims 3 to 6, wherein the in-situ polymerization type composition contains (4) and the diol of (4) is a bifunctional phenol compound. The vehicle-mounted camera according to any one of claims 1, 3 to 7, wherein the primer layer has a curable resin layer formed from a composition containing a curable resin between the in-situ polymerization composition layer and the thermoplastic resin material. The vehicle-mounted camera according to claim 8, wherein the curable resin is at least one selected from the group consisting of urethane resin, epoxy resin, vinyl ester resin, and unsaturated polyester resin. The vehicle-mounted camera according to any one of claims 1 to 9, wherein both the first resin member and the second resin member have the primer layer, and the primer layer of the first resin member and the primer layer of the second resin member are welded together. The vehicle-mounted camera according to any one of claims 1 to 10, wherein the monomer occupying the maximum content among the monomers constituting the thermoplastic resin constituting the thermoplastic resin material of the second resin member is the same as the monomer occupying the maximum content among the monomers constituting the thermoplastic resin constituting the thermoplastic resin material of the first resin member, and the content of each of the monomers is 70 mass% or more. The vehicle-mounted camera according to any one of claims 1 to 11, wherein the thermoplastic resin material of the first resin member or the second resin member contains polypropylene and at least one reinforcing material selected from the group consisting of talc, glass fiber, and carbon fiber, and the first resin member or the second resin member has a tensile strength of 40 MPa or more and a Young's modulus of 3 GPa or more. The vehicle-mounted camera according to any one of claims 1 to 11, wherein the thermoplastic resin material of the first resin member or the second resin member contains polyetherimide and at least one reinforcing material selected from the group consisting of talc, glass fiber, and carbon fiber, and the first resin member or the second resin member has a tensile strength of 90 MPa or more and a Young's modulus of 3 GPa or more. A method for manufacturing an in-vehicle camera according to any one of claims 1 to 13, comprising heating the primer layer and welding the first resin member and the second resin member by pressing the first resin member and the second resin member together so that the heated primer layer is interposed between the first resin member and the second resin member.

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