joint

Abstract

To provide a joint body having excellent joint strength.SOLUTION: A joint body has a metal member having a roughened surface with irregularities thereon, and a resin member joined to the metal member through the roughened surface. The resin member has, in order from the side in contact with the roughened surface, a skin layer and a core layer. Projections of the irregularities on the roughened surface project to penetrate the skin layer of the resin member.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to conjugates. [Background technology]

[0002] For the purpose of reducing the weight of various molded articles used in vehicles, etc., dissimilar metal joining between steel materials and lightweight metal materials such as aluminum alloys and magnesium alloys, dissimilar material joining between steel materials or lightweight metal materials and resin materials, etc., are being considered. Dissimilar material joining between steel materials or lightweight metal materials and resin materials is expected to further reduce the weight.

[0003] Therefore, a new method for producing a composite molded body by joining and integrating a metal molded body and a resin molded body has been investigated. For example, as a method capable of increasing the processing speed and also increasing the bonding strength in different directions, a method for roughening the surface of a metal molded body and a method for manufacturing a composite molded body have been proposed in which the surface of the metal molded body is roughened by continuously irradiating the surface with laser light using a continuous wave laser at an irradiation speed of 2000 mm / sec or more (see, for example, Patent Documents 1 and 2). In Patent Documents 1 and 2, the surface of a metal molded body is roughened, and then the metal molded body and a resin molded body are joined and integrated by injection molding to produce a composite molded body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5774246 [Patent Document 2] Patent No. 5701414 Summary of the Invention [Problem to be solved by the invention]

[0005] Although the composite molded bodies formed by the methods described in Patent Documents 1 and 2 have high strength, the strength may still be insufficient depending on the application of the composite molded body, and further improvement in strength is desired. The present disclosure has been made in view of the above-described conventional circumstances, and has an object to provide a bonded body having excellent bonding strength. [Means for solving the problem]

[0006] Specific means for achieving the above object are as follows. <1> A metal member having a roughened surface with projections and recesses, and a resin member bonded to the metal member via the roughened surface, the resin member has a skin layer and a core layer in this order from the side in contact with the roughened surface, A bonded structure in which the convex portions of the irregularities on the roughened surface protrude to penetrate the skin layer of the resin member. <2> An intermediate layer is present between the skin layer and the core layer. <1> The conjugate according to claim 1. <3> The convex portions of the irregularities on the roughened surface protrude until they reach the core layer of the resin member. <1> or <2> The conjugate according to claim 1. <4> The roughened surface is formed by laser roughening. <1> ~ <3> The conjugate according to any one of the preceding claims. <5> When a cross section perpendicular to the roughened surface is observed, the ratio (B / A) of the length A of the interface between the skin layer and the core layer to the total length B of the widths of the convex portions at the interface is 10% to 50%. <1> ~ <4> The conjugate according to any one of the preceding claims. [Effects of the Invention]

[0007] According to the present disclosure, a bonded body having excellent bonding strength can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] 10 is an electron microscope photograph of a joint portion of a joined body after a strength test of the joint portion between a metal member and a resin member is conducted. [Figure 2] 10 is a diagram illustrating the state of a cross section of a portion of a joined body where a metal member and a resin member are joined, the cross section being perpendicular to the joining surface between the metal member and the resin member; FIG. [Figure 3] FIG. 1 is a diagram for explaining the shape of a test piece conforming to ISO19095. [Figure 4] FIG. 1 is a diagram obtained by plotting the evaluation results of test pieces No. 1 to No. 20. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the present disclosure.

[0010] In the present disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples. In the present disclosure, the terms "layer" and "film" include cases where the layer or film is formed over the entire area when the area in which the layer or film is present is observed, as well as cases where the layer or film is formed over only a portion of the area. In the present disclosure, "(meth)acrylic" means at least one of acrylic and methacrylic.

[0011] <zygote> The bonded structure of the present disclosure comprises a metal member having a roughened surface with irregularities, and a resin member joined to the metal member via the roughened surface, wherein the resin member has a skin layer and a core layer, in that order from the side contacting the roughened surface, and the convex portions of the irregularities on the roughened surface protrude until they penetrate the skin layer of the resin member. The bonded structure of the present disclosure has excellent bonding strength. The reason for this is not clear, but is presumed to be as follows.

[0012] When an external force is applied to a bonded structure having a joint between a metal member and a resin member, and the bonded structure is destroyed, if the resin constituting the resin member is sufficiently filled between the irregularities on the roughened surface of the metal member at the joint, the resin member itself is more likely to be destroyed than peeling from the interface between the metal member and the resin member. In other words, the strength of the bonded structure depends on the strength of the resin constituting the resin member, and is less affected by the bond strength at the interface between the metal member and the resin member. Fig. 1 is an electron microscope photograph of the bonded portion of a bonded assembly after a strength test of the bonded portion between a metal member 10 and a resin member 12. In Fig. 1, there are a roughened region X and a non-roughened region Y on the surface of the metal member 10. In region Y on the surface of the metal member 10, it can be seen that the metal member 10 and the resin member 12 have peeled off at the interface. On the other hand, in region X on the surface of the metal member 10, it can be seen that the resin member 12 itself has been destroyed. Generally, when a joined body is formed by a method for molding a resin molded body such as injection molding, the resin member has a skin layer and a core layer in this order from the side that contacts the metal member. The resin of the skin layer has a higher orientation than the resin of the core layer, and is therefore more likely to have a decrease in strength in the thickness direction. In the joined structure of the present disclosure, the convex portions of the unevenness of the roughened surface of the metal member protrude through the skin layer of the resin member, and the anchoring effect of the convex portions makes it possible to suppress fracture in the skin layer, which is presumably why the joined structure of the present disclosure has excellent joining strength.

[0013] In this disclosure, the term "skin layer" refers to the area where the molten resin cools and solidifies immediately after contacting the metal surface of a mold, metal member, or the like, and becomes a film-like state, and the term "core layer" refers to the area where the molten resin flows without coming into contact with the metal surface of a mold, metal member, or the like and then solidifies.

[0014] The metal members and resin members constituting the joined body, the method for manufacturing the joined body, etc. will be described in detail below.

[0015] (Metal parts) The metal member used in the present disclosure is not particularly limited as long as it has a roughened surface with irregularities on the joining surface with the resin member, and can be appropriately selected from known metal materials depending on the application of the joined body. Examples of metals constituting the metal member include iron, aluminum, zinc, titanium, copper, magnesium, and alloys containing these. Examples of alloys include various stainless steels and copper-zinc alloys (brass). The surface of the metal member to be joined with the resin member may be subjected to a surface treatment such as plating or alumite treatment.

[0016] The shape of the metal member is not particularly limited and can be appropriately selected depending on the application of the bonded body formed using the metal member. Examples of the shape of the metal member include a plate shape, a spherical shape, a shape having a curved surface, a shape having a step, etc. The roughened surface of the metal member may be provided on the entire surface to be joined with the resin member, or may be provided on only a part of the surface to be joined with the resin member. When the roughened surface is provided on a part of the joining surface of the metal member with the resin member, the joining surface preferably has a non-roughened smooth portion and an uneven portion corresponding to the roughened surface, and when the surface of the smooth portion is taken as a reference surface, the uneven portion preferably has a plurality of convex portions that protrude to a position higher than the reference surface. By having the convex portions that protrude to a position higher than the reference surface, it becomes easy to make the convex portions protrude until they penetrate the skin layer of the resin member.

[0017] The height of the convex portion from the reference plane is preferably greater than the thickness of the skin layer. The height is greater than the thickness of the skin layer, which tends to further improve the bonding strength between the resin member and the metal member. Although there is no particular upper limit to the height of the convex portion from the reference plane, the height may be 1000 μm or less from the viewpoints of productivity of the metal member and reduction of damage to the metal member. The height of the convex portion from the reference plane is preferably 15 μm to 1000 μm, more preferably 50 μm to 1000 μm, and even more preferably 500 μm to 1000 μm. The density of the convex parts in the uneven part is 5 / mm 2 ~50 pieces / mm 2 It is preferable that the density is 10 / mm 2 ~30 pieces / mm 2 More preferably, it is 10 pieces / mm 2 ~25 pieces / mm 2 It is more preferable that:

[0018] The method for forming a roughened surface having projections and recesses on a metal member is not particularly limited. Examples of methods for forming a roughened surface on a metal member include a chemical treatment method such as etching, and a laser roughening method in which the surface of the metal member is irradiated with laser light to form projections and recesses. Among these, the laser roughening method is preferred because it can easily form projections that protrude to a position higher than the reference surface.

[0019] Various conditions when a method of forming a roughened surface by irradiating the surface of a metal member with laser light is employed will be described below. The various conditions below are set appropriately in consideration of the type of metal constituting the metal member, the height of the convex portion, and the like.

[0020] When irradiating the surface of a metal member with laser light to provide a roughened surface, a pulsed laser or a continuous wave (CW) laser may be used. When a CW laser is used, the CW laser may be a modulated CW laser that periodically changes the laser output.

[0021] When a CW laser is used, the irradiation speed (scanning speed) of the CW laser is not particularly limited. The irradiation speed of the CW laser is preferably 100 mm / sec to 2000 mm / sec. If the irradiation speed of the CW laser is 100 mm / sec or more, the processing speed of the metal component tends to be increased. If the irradiation speed of the CW laser is 2000 mm / sec or less, it tends to be easier to make the height of the convex portion from the reference surface greater than the thickness of the skin layer.

[0022] The irradiation output of the laser is not particularly limited. For example, when a CW laser is used, the laser output is preferably 6W to 500W. If the laser output of the CW laser is 6 W or more, it tends to be easier to make the height of the convex part from the reference plane greater than the thickness of the skin layer. If the laser output of the CW laser is 500 W or less, it tends to be possible to downsize the laser light irradiation equipment.

[0023] The spot diameter of the laser is not particularly limited. For example, the laser spot diameter is preferably 10 μm to 50 μm.

[0024] When a modulated CW laser is used, the modulation method may be a sine wave, a triangular wave, or a square wave. The frequency of the modulated CW laser is preferably 1000 Hz to 10000 Hz. In a modulated CW laser, when the maximum laser output is taken as 100, the minimum laser output is preferably 30 or more and less than 100, more preferably 50-95, and even more preferably 80-90.

[0025] When the surface of the metal member is irradiated with laser light, a roughened surface may be formed by wobbling. Furthermore, the area that has been irradiated once with laser light may be repeatedly irradiated with laser light. When laser light is repeatedly irradiated, the number of repetitions is preferably 1 to 40 times.

[0026] Examples of lasers that can be used include solid-state lasers such as ruby ​​lasers, YAG (yttrium aluminum garnet) lasers, and titanium sapphire lasers; liquid lasers such as dye lasers; gas lasers such as helium-neon lasers, argon ion lasers, carbon dioxide lasers, nitrogen lasers, and excimer lasers; semiconductor lasers; and fiber lasers. The laser may be a green laser.

[0027] When the surface of a metal member is irradiated with laser light to form a roughened surface, compressed air may be supplied to the area of ​​the metal member surface that is irradiated with the laser light. The pressure of the supplied compressed air is preferably 0.2 MPa to 0.5 MPa, from the viewpoint of efficiently removing metal powder generated by the irradiation with the laser light.

[0028] When the laser light is irradiated linearly, the scanning interval of the laser light is preferably larger than the spot diameter of the laser light.

[0029] (Resin parts) The resin member used in the present disclosure is not particularly limited as long as it is used for joining to a metal member, and any conventionally known resin can be appropriately selected and used depending on the application of the joined body. Examples of the resin include a thermosetting resin, a thermoplastic resin, and an elastomer.

[0030] Specific examples of thermosetting resins include phenolic resins, unsaturated imide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, melamine resins, resorcinol resins, and epoxy resins. Specific examples of thermoplastic resins include polyimide resin, polyamideimide resin, polyamide resin, polyetherimide resin, polybenzoxazole resin, polybenzimidazole resin, polystyrene resin, acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile-styrene copolymer resin, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polycarbonate resin, (meth)acrylic resin, polyester resin, polyacetal resin, and polyphenylene sulfide resin. Specific examples of elastomers include silicone rubber, styrene butadiene rubber (SBR), nitrile rubber (NBR), and urethane rubber.

[0031] The resin member may contain other components in addition to conventionally known resins depending on the intended use of the bonded body, such as a particulate filler, a fibrous filler, and a release agent.

[0032] Other components may further include a curing agent that cures the thermosetting resin, a curing accelerator that accelerates the curing of the thermosetting resin, and a surface treatment agent that modifies the surface of the inorganic material.

[0033] The content of components other than the resin contained in the resin member may be appropriately set depending on the application of the bonded body.

[0034] (Method of manufacturing a bonded body) The method for producing the bonded body is not particularly limited, and can be any of the usual methods for molding resin molded bodies, such as injection molding, blow molding, compression molding, transfer molding, extrusion molding, cast molding, etc. Alternatively, the bonded body can be produced by applying a resin composition containing a resin and, if necessary, other components to the roughened surface of the metal member by insert molding. From the viewpoint of preventing deformation of the convex portions on the roughened surface of the metal member and improving the bonding strength between the metal member and the resin member, the bonded body is preferably manufactured by insert molding. When a thermosetting resin is used as a component of the resin member, the resin member may be hardened by heat treatment after joining the metal member and the resin member by the above method.

[0035] As described above, the resin member has a skin layer and a core layer in this order from the side that contacts the metal member, and depending on conditions such as the type of resin constituting the resin member, the injection pressure of the resin, and the temperature of the metal member during resin molding, an intermediate layer with a higher orientation than the core layer may be formed between the skin layer and the core layer. In this case, it is preferable that the convex portions of the unevenness of the roughened surface protrude all the way to the core layer of the resin member.

[0036] 2 is a diagram illustrating the state of a cross section perpendicular to the roughened surface of the metal member (i.e., the bonding surface between the metal member and the resin member) at the bonded portion of the bonded body. In FIG. 2, a metal member 10 is bonded via a roughened surface 14 to a resin member 12 having a skin layer 16 and a core layer 18. The roughened surface 14 has a plurality of convex portions 20, which protrude through the skin layer 16 and reach the core layer 18. In the bonded body shown in FIG. 2, the ratio (B / A) of the length A of the interface 22 between the skin layer 16 and the core layer 18 to the total length B of the widths of the convex portions 20 at the interface 22 is preferably 10% to 50%, more preferably 10% to 30%, and even more preferably 20% to 30%. When the ratio (B / A) is in the range of 10% to 50%, the bonding strength of the bonded body tends to be further improved.

[0037] Applications of the joined article of the present disclosure include various molded articles used in vehicles, etc., and specific examples include, but are not limited to, side doors, hoods, roofs, back doors, luggage doors, bumpers, and crash boxes. [Example]

[0038] The present disclosure will be described below based on examples, but the present disclosure is not limited to the following examples.

[0039] As shown in FIG. 3(A), a donut-shaped metal member 100 made of aluminum (AL3003) conforming to ISO19095 and having an outer diameter of φ55 mm, an inner diameter of φ20 mm, and a thickness of 2 mm was prepared. A roughened surface 102 was formed on one side of the metal member 100 using a fiber laser (LP-M (FAYb laser marker) manufactured by Panasonic Corporation) or a fiber laser (ML6811C (CW laser) manufactured by Amada Miyachi Co., Ltd.). The width of the roughened surface 102 was 2 mm. The laser power was adjusted, and the height of the convex portions of the unevenness of the roughened surface 102 was measured using a micrometer. The results obtained are shown in Tables 1 and 2. Five test pieces were prepared for each laser output. For test pieces Nos. 1 to 20, a fiber laser manufactured by Panasonic Corporation was used. For test pieces Nos. 21 to 25, a fiber laser manufactured by Amada Miyachi Co., Ltd. was used.

[0040] [Table 1]

[0041] [Table 2]

[0042] Next, a resin member 104 as shown in Fig. 3(B) was injection molded using an injection molding machine LA60 manufactured by Sodick Corporation under conditions of a resin heating temperature of 320°C and a mold temperature of 150°C so as to cover the roughened surface 102 of each test piece, thereby obtaining a test piece. The size of the resin member 104 was an outer diameter of φ26 mm and a thickness of 2 mm. The resin used was polyphenylene sulfide (PPS) resin manufactured by DIC Corporation. Using each test piece, the bonding strength was evaluated by the following method. Furthermore, when the cross section of the joint of the test piece was observed under a polarizing microscope, the thickness of the skin layer of the resin member was found to be 10 μm.

[0043] The bond strength of each test piece was determined using an autograph (AG-IS (product name)) manufactured by Shimadzu Corporation. For each test piece, the resin member was pressed through the hole in the test piece using a special measuring tool from the side opposite to the side on which the resin member was formed. The maximum value of the pressing force on the resin member was taken as the bond strength (N). The results obtained are shown in Tables 1 and 2. The evaluation results of test pieces No. 1 to No. 20 are plotted in Figure 4. As is clear from Figure 4, the bonding strength of test pieces No. 6 to No. 20, in which the height of the convex portion is greater than 10 μm, which is the thickness of the skin layer of the resin member, is higher than the bonding strength of test pieces No. 1 to No. 5, in which the height of the convex portion is less than 10 μm, which is the thickness of the skin layer of the resin member. It is also clear that the bonding strength differs significantly at the boundary of 10 μm, which is the thickness of the skin layer of the resin member. In test pieces No. 1 to No. 20, fracture occurred near the interface at the joint between the metal member 100 and the resin member 104. On the other hand, in test pieces No. 21 to No. 25, fracture occurred in the resin part 104 itself, and fracture did not occur at the joint between the metal member 100 and the resin member 104. The fracture modes were different between test pieces No. 1 to No. 20 and test pieces No. 21 to No. 25. [Explanation of symbols]

[0044] 10 Metallic parts 12 Resin parts 14 Roughened surface 16 Skin Layer 18 Core Layer 20 Convex part 22 Interface

Claims

1. The present invention comprises a metal member having a roughened surface having projections and recesses with a height of 500 μm to 1000 μm from a reference surface, and a resin member bonded to the metal member via the roughened surface, the roughened surface is provided on a part of a joining surface of the metal member with the resin member, the joining surface has a smooth portion that is not roughened, The surface of the smooth portion is the reference surface, the resin member has a skin layer and a core layer in this order from the side in contact with the roughened surface, a convex portion of the concave-convex portion of the roughened surface protrudes until it penetrates the skin layer of the resin member; a bonded body, wherein, when a cross section perpendicular to the roughened surface is observed, the ratio (B / A) of a length A of the interface between the skin layer and the core layer to a total length B of the widths of the convex portions at the interface is 10% to 50%.

2. The bonded body according to claim 1 , wherein the convex portions of the irregularities on the roughened surface protrude to reach the core layer of the resin member.

3. 3. The bonded structure according to claim 1, wherein the roughened surface is formed by laser roughening.

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