JP2021120195A - Bonding structure - Google Patents

Abstract

To provide a bonding structure of metal and resin that has a high bonding strength.SOLUTION: The bonding structure includes a first member 1 that is a metal work piece having protrusions 3 aligned on the surface, and a thermoplastic resin-containing second member 2 that is bonded to the first member via the protrusions 3. The height of the protrusions is 15 to 200 μm, the width of the protrusions is 10 to 200 μm, the interval between the protrusions is 10 to 200 μm, and, when viewed from the tip side of the protrusions, the arrangement of the protrusions is at least one of a triangular shape, a quadrangular shape, and a hexagonal shape.SELECTED DRAWING: Figure 1

Description

The present invention relates to a bonded structure of a metal and a resin.

For example, a metal-resin bonding structure such as a sensor that requires metal-resin bonding or a relay that requires metal-resin bonding is used in many industrial fields. Various methods are used for joining the metal and the resin.

For example, in Patent Document 1, a plurality of depressions or grooves are provided on the surface of a metal member by a high-energy beam, and a spherical ridge or a spherical tip formed of a melt of the metal member is formed on the surface thereof. A composite molded body of a metal member and a molded resin member is disclosed in which a metal droplet solidifying portion formed of a raised portion having a constricted portion having a knob is provided and the surface thereof is molded with a resin member.

Further, Patent Document 2 describes a step of pressing a planned joining surface of a metal base material having a superposed fine particle structure and a step of pressing a planned joining surface of a plastic, and a step of irradiating the pressed interface with laser light to heat the pressed interface. A method for joining a metal base material and a plastic including a step of engaging the plastics melted by heating by entering and wrapping the superposed fine particle structure and engaging with each other is disclosed.

Patent Document 3 discloses a joint structure composed of a first member in which a perforated portion having an opening is formed and a second member filled in the perforated portion. The perforation has an enlarged diameter portion in which the opening diameter increases in the depth direction and a reduced diameter portion in which the opening diameter decreases in the depth direction, and the enlarged diameter portion is formed on the surface side and the reduced diameter portion is formed on the bottom side. The joining structure is disclosed.

Japanese Unexamined Patent Publication No. 2013-71312 Japanese Unexamined Patent Publication No. 2016-130003 International Publication No. 2016/0277775

According to the method for producing a composite molded product according to Patent Document 1, the metal surface has a rough surface shape due to a raised portion, spherical metal droplets, and granular spatter, so that the resin can sufficiently enter the rough surface portion. It is said that a resin composite molded product having adhesiveness and airtightness can be manufactured at low cost.

Further, according to the joining method according to Patent Document 2, when the plastic enters or wraps in the fine particle structure formed by the metal powder adhering to the metal surface, an anchor effect is exhibited, and in either direction of shearing or peeling. However, it is said that a bonded body having mechanical strength can be obtained.

However, in the inventions according to Patent Documents 1 and 2, since the processed shape is complicated and it is difficult to control the processed shape, it is not always possible to obtain a desired processed shape at an arbitrary location, and the stability is stable. Lacking. Also in the invention according to Patent Document 2, the anchor effect is insufficient because the metal powder is only adhered to the surface of the metal base material, and therefore there is still room for improvement in the strength of the entire joint. There is.

According to the method for manufacturing a joint structure according to Patent Document 3, since the enlarged diameter portion of the joint structure protrudes inward in the perforation, the enlarged diameter portion and the second member filled in the perforation are separated in the peeling direction. Engagement is said to improve the joint strength in the peeling direction.

However, in the invention according to Patent Document 3, since the perforations that exhibit the anchor effect are independent, when stress such as thermal shock is applied, the second member filled in the perforations is sequentially destroyed from the portion where the stress is concentrated. .. Therefore, the durability of the joint depends only on the strength of the resin contained in the second member. In particular, when the second member contains a fiber reinforced resin, the bundled fibers are not inserted into the perforation, and only the resin is filled in the perforation, so that the resin exhibits lower strength than the original. In some cases.

Therefore, the present inventor has found that it is difficult to produce a bonded structure exhibiting high bonding strength when a metal and a resin are used by the conventional method.

One aspect of the present invention has been made in view of such circumstances, and an object of the present invention is to provide a bonded structure of a metal and a resin having high bonding strength.

The present invention employs the following in order to solve the above-mentioned problems.

That is, the bonding structure according to one aspect of the present invention comprises a first member which is a metal processed product having protrusions aligned on the surface and a thermoplastic resin which is bonded to the first member via the protrusions. It includes a second member including.

In the above configuration, a physically strong anchor effect can be obtained between the first member and the second member by solidifying the protrusions aligned on the surface of the metal processed product so as to be covered with the thermoplastic resin. According to the above configuration, the joint structure has improved joint strength. As used herein, the term "aligned protrusions" means regularly arranged protrusions.

In the joint structure according to the one side surface, the height of the protrusion may be 15 to 200 μm. According to this configuration, the anchor effect is likely to be exhibited. As used herein, the "protrusion height" means the distance from the tip to the base of the protrusion. Further, in the present specification, the “tip of the protrusion” means a portion of the protrusion that first comes into contact with the plane when the plane is brought closer from the side where the protrusion protrudes.

In the joint structure according to the one side surface, the width of the protrusion may be 10 to 200 μm. According to this configuration, the anchor effect is likely to be exhibited. In the present specification, the "protrusion width" means the maximum ferret diameter of the protrusion contour line seen from the tip side of the protrusion.

In the joint structure according to the one side surface, the distance between the protrusions may be 10 to 200 μm. According to this configuration, the anchor effect is likely to be exhibited. As used herein, the term "protrusion spacing" means the distance at which the contour lines of the protrusions first come into contact with the contour lines of other adjacent protrusions when the contour lines of the protrusions are expanded equidistantly when viewed from the tip end side of the protrusions.

In the joint structure according to the one side surface, the arrangement of the protrusions may be at least one of a triangular shape, a quadrangular shape, and a hexagonal shape when viewed from the tip end side of the protrusions. In the configuration, if the arrangement is triangular, the protrusions are arranged most closely, so that the vertical peeling strength is improved. Further, if the arrangement is square, the anisotropy of the shear strength becomes small. Further, when the arrangement is hexagonal, the anisotropy of shear strength is smaller than that of the square arrangement.

As used herein, the "square" arrangement of protrusions means that the arrangement of protrusions is grid-like. As used herein, the "triangular" arrangement of protrusions means that the protrusions are closest packed on the surface of the first member. Further, in the present specification, the arrangement of the protrusions is "hexagonal" means that the arrangement of the protrusions is a hexagonal shape.

In the joint structure according to the one side surface, the protrusion has at least one of a region in which the diameter of the cross section perpendicular to the height direction of the protrusion expands from the tip of the protrusion toward the base and a region in which the diameter decreases. May be good. According to this configuration, the shape of the protrusions makes it easier for the anchor effect to be exhibited, so that the vertical peeling strength is further improved.

In the joint structure according to the one side surface, the diameter of the cross section perpendicular to the height direction of the protrusion may be increased from the tip of the protrusion toward the base and then reduced. According to this configuration, the shape of the protrusions makes it easier for the anchor effect to be exhibited, so that the vertical peeling strength is further improved.

In the joint structure according to the one side surface, the diameter of the cross section perpendicular to the height direction of the protrusion may be reduced from the tip of the protrusion toward the base and then expanded. According to this configuration, the shape of the protrusions makes it easier for the anchor effect to be exhibited, so that the vertical peeling strength is further improved.

In the joint structure according to the one side surface, the diameter of the cross section perpendicular to the height direction of the protrusion may be reduced from the tip to the base of the protrusion. According to this configuration, the shape of the protrusions makes it easier for the anchor effect to be exhibited, so that the vertical peeling strength is further improved.

In the joint structure according to the one side surface, the diameter of the cross section perpendicular to the height direction of the protrusion may be expanded from the tip to the base of the protrusion. According to this configuration, the anchor effect can be obtained by the shape of the protrusion.

In the joint structure according to the one side surface, the diameter of the cross section perpendicular to the height direction of the protrusion may be constant from the tip to the base of the protrusion. According to this configuration, the anchor effect can be obtained by the shape of the protrusion.

According to one aspect of the present invention, it is possible to provide a bonded structure of a metal and a resin having high bonding strength.

FIG. 1 schematically illustrates an example of a cross section of the joint structure according to the embodiment. FIG. 2 schematically shows a method of laser irradiation for forming a protrusion according to an embodiment. FIG. 3 schematically shows an example of a protrusion of the first member according to the embodiment. FIG. 4 schematically shows an example of a protrusion of the first member according to the embodiment. FIG. 5 schematically shows an example of a protrusion of the first member according to the embodiment. FIG. 6 schematically shows an example of a protrusion of the first member according to the embodiment. FIG. 7 schematically shows an example of a protrusion of the first member according to the embodiment. FIG. 8 schematically shows an example of the arrangement of the protrusions of the first member according to the embodiment. FIG. 9 schematically shows an example of the arrangement of the protrusions of the first member according to the embodiment. FIG. 10 schematically shows an example of the arrangement of the protrusions of the first member according to the embodiment. FIG. 11 schematically shows a laser-machined portion of the first member according to the embodiment. FIG. 12 schematically shows a joint structure used in the vertical peeling test according to the embodiment. FIG. 13 schematically shows a method of a vertical peeling test according to an embodiment. FIG. 14 schematically shows a joint structure used in the shear test according to the embodiment. FIG. 15 schematically shows a shear test method according to an example. FIG. 16 represents an optical microscope image showing the protrusions according to the first embodiment. FIG. 17 represents an optical microscope image showing the protrusions according to the second embodiment. FIG. 18 represents an optical microscope image showing the protrusions according to Example 3. FIG. 19 represents an optical microscope image showing the protrusions according to the fourth embodiment. FIG. 20 represents an optical microscope image showing a protrusion according to Example 5.

Hereinafter, embodiments according to one aspect of the present invention (hereinafter, also referred to as “the present embodiment”) will be described with reference to the drawings.

§1 Application example First, the outline of the bonded structure according to one aspect of the present invention will be described with reference to FIG. FIG. 1 schematically illustrates an example of a cross section of the bonded structure according to one aspect.

In FIG. 1, a first member 1 which is a metal processed product having protrusions 3 aligned on the surface, a second member 2 containing a thermoplastic resin which is joined to the first member 1 via the protrusions 3, and a second member 2. A bonded structure comprising the above is exemplified.

Since the second member 2 is solidified so as to wrap the protrusion 3 formed on the first member 1, a physically strong anchor effect can be obtained. That is, the second member 2 is not in the form of being filled in the perforation as in Patent Document 3. Therefore, in the second member 2, stress does not concentrate on the resin portion filled in the perforation. As a result, when the joint structure is broken, the broken portion of the joint becomes a metal protrusion or the entire second member. In addition, the second member is not easily broken because the stress is easily dispersed over the entire joint. Further, since the situation where only the resin is filled without inserting the fibers or crystals during drilling does not occur, the strength of the resin as generated in Patent Document 3 even when the fiber reinforced resin or the crystalline resin is used. Does not decrease.

Further, since the protrusions 3 are aligned, the strength of the entire joint structure is stable. In addition, the metal and the resin can be directly bonded without the need for an intermediate layer or an adhesive for bonding. Therefore, it is possible to provide a bonded structure that exhibits high bonding strength.

§2 Configuration example <First member>
The first member is a metal work piece having protrusions aligned on the surface. Examples of the material of the metal processed product include iron-based metal, stainless-based metal, copper-based metal, aluminum-based metal, magnesium-based metal, and alloys thereof. Further, the metal processed product may be a metal molded product, zinc die-cast, aluminum die-cast, powder metallurgy, or the like.

<Protrusion>
The protrusions are aligned protrusions formed on the surface of the first member. When the first member is provided with the protrusions, an anchor effect can be obtained between the first member and the thermoplastic resin, which is the second member, via the protrusions. Therefore, the joint strength is improved.

The protrusion is preferably formed integrally with the first member. That is, it is preferable that the protrusion formed as a member different from the first member is not attached to the surface of the first member. As a result, the joint strength is improved as compared with the case where the protrusion is attached to the first member.

The height of the protrusions is preferably 15 μm or more and 200 μm or less, more preferably 20 μm or more and 100 μm or less. If the height of the protrusion is 15 μm or more, the anchor effect is improved. Further, when the height of the protrusion is 200 μm or less, the resin filling property is improved.

The width of the protrusions is preferably 10 μm or more and 200 μm or less, more preferably 20 μm or more and 100 μm or less. When the width of the protrusion is 10 μm or more, the protrusion can be easily formed. When the width of the protrusions is 200 μm or less, the number of protrusions per unit area increases and the anchor effect is improved.

The distance between the protrusions is preferably 10 μm or more and 200 μm or less, and more preferably 20 μm or more and 100 μm or less. When the distance between the protrusions is 10 μm or more, the resin filling property is excellent. Further, when it is 200 μm or less, the number of protrusions per unit area increases and the anchor effect is improved. From the viewpoint of obtaining stable strength, it is preferable that the distance between the protrusions is constant.

The shape of the protrusion is not particularly limited. For example, the protrusion may have a constant diameter of the cross section perpendicular to the height direction, and at least one of a region in which the diameter of the cross section perpendicular to the height direction expands and contracts from the tip to the base of the protrusion. It may have either one. In particular, when the protrusion has a region in which the diameter of the cross section perpendicular to the height direction decreases from the tip of the protrusion toward the base, the vertical peeling strength is excellent.

3 to 7 schematically show an example of a protrusion. The protrusion 3 shown in FIG. 3 includes a region 22 in which the diameter of the cross section perpendicular to the height direction expands from the tip of the protrusion toward the base, and then decreases. The protrusion 3 shown in FIG. 4 includes a region 21 in which the diameter of the cross section perpendicular to the height direction expands next to the region 22 in which the diameter of the cross section decreases from the tip of the protrusion toward the base. The protrusion 3 shown in FIG. 5 includes only a region 22 in which the diameter of the cross section perpendicular to the height direction is reduced from the tip to the base of the protrusion. The protrusion 3 shown in FIG. 6 includes only a region 21 in which the diameter of the cross section perpendicular to the height direction expands from the tip to the base of the protrusion. In the protrusion 3 shown in FIG. 7, the diameter of the cross section perpendicular to the height direction is constant from the tip to the base of the protrusion. Further, the protrusions having a plurality of shapes may be partially used. That is, for example, the shape shown in FIG. 3 and the shape shown in FIG. 4 may coexist.

The arrangement of the protrusions is not particularly limited. 8 to 10 schematically illustrate an example of the arrangement of protrusions. In FIGS. 8 to 10, for convenience, the shape in which the tips of the protrusions are connected is shown by a thick line. The arrangement of the protrusions as seen from the tip side of the protrusions may be, for example, a quadrangular shape as shown in FIG. 8, a triangular shape as shown in FIG. 9, or a hexagonal shape as shown in FIG. good. In addition, a plurality of types of arrays may be partially used. That is, for example, the sequence shown in FIG. 8 and the sequence shown in FIG. 9 may coexist.

<Second member>
The second member contains a thermoplastic resin. Examples of the material of the second member include PMMA (polymethylmethacrylate), PC (polypolyamide), PS (polyamide), PAR (polyaraylate), PES (polyethersulfon), PEI (polyetherimide), and COC (. Cycloolefin copolymer), COP (cycloolefin polymer), fluorene derivative, EFEP (ethylene tetrafluoroethylene copolymer), PSU (polysulfone), PPSU (polyphenylsulfone), AS (acrylonitrile / styrene), LDPE (low) Density polyethylene), PP (polyethylene), PE (polyethylene), PBT (polybutylene terephthalate), PET (polyethylene terephthalate), PA (polyamide), PA6 (polyamide 6), PA66 (polyamide 66), POM (polyacetal), PPS (Polyphenylene sulfide), PVC (polyvinyl chloride), PPVDC (polyvinylidene chloride), and PVDF (vinylidene fluoride). The resin member may be TPE (thermoplastic elastomer), and examples of TPE include TPO (olefin type), TPS (styrene type), TPEE (ester type), TPU (urethane type), and TPA (nylon type). System), TPVC (vinyl chloride system) and the like. Among the above, a thermoplastic resin having crystallinity is preferable from the viewpoint of material strength.

Further, a filler may be added to the resin. Examples of the filler include inorganic fillers (glass fibers, inorganic salts, etc.), metal fillers, organic fillers, carbon fibers and the like.

The second member may contain an additive other than the thermoplastic resin and the filler, if necessary, as long as the above-mentioned effects are not impaired. Examples of additives include sizing agents, dispersants, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, lubricants, crystal nucleating materials, plasticizers, dyes, pigments, carbon nanotubes and the like.

It is preferable to use a layered silicate as the crystal nucleating material for the purpose of improving the material strength of the second member. In the layered silicate, a tetrahedron in which Si is surrounded by four oxygens forms a two-dimensionally expanded structural unit (tetrahedron sheet) by sharing three vertices with the adjacent tetrahedron. It is a group of silicates with a layered structure. Further, a part of Si may be replaced with Al. Examples of the silicate include mica, mica, talc, kaolin, montmorillonite and the like. Further, an octahedral sheet, which is a two-dimensional connection of octahedrons in which Mg, Al, etc. are surrounded by six oxygens or OHs in addition to Si, is also a crystal nucleating agent. The octahedral sheet has a complete cleavage parallel to the layer surface and is generally in the form of a plate or flakes. The octahedral sheet is chemically a hydrous silicate containing Al, Mg, Fe, alkali and the like in addition to Si. Commercially available products can be used for both.

<Manufacturing method of joint structure>
The joined structure is obtained, for example, by a manufacturing method including a step of joining the first member and the second member.

The method for manufacturing the joined structure may include a step of forming a protrusion on the first member before the step of joining the first member and the second member. The method of forming the protrusions of the first member is not particularly limited, and may be performed by laser processing, chemical etching, or the like.

Examples of the laser used for forming the protrusions include a fiber laser, a YAG laser, a YVO4 laser, a semiconductor laser, a carbon dioxide gas laser, and an excimer laser. A pulse laser is suitable when forming a protrusion having a region in which the diameter of the cross section perpendicular to the height direction of the protrusion decreases from the tip of the protrusion toward the base, and in other cases, a continuous wave laser may be used. As the pulse laser, a sub-pulse laser is more preferable.

FIG. 2 schematically shows a method of laser irradiation for forming a protrusion according to an embodiment. By laser processing the metal so that the laser irradiation portion 11 shown in FIG. 2 partially overlaps with the metal, the laser non-irradiation portion 13 becomes an independent protrusion. In FIG. 2, the region where the laser irradiation unit overlaps is shown as the laser irradiation superimposing unit 12.

Examples of the method for joining the first member and the second member include laser joining, injection molding joining, ultrasonic welding, hot press welding and the like.

Laser bonding is performed, for example, as follows. The processed portion of the first member is irradiated with a laser while pressing the second member, and the second member is melted by heat. The direction of irradiating the laser is from the second member side when the second member transmits the laser, and from the first member side when the second member does not transmit the laser. After that, when the laser irradiation is stopped, the second member is cooled and solidified so as to wrap the protrusions, thereby obtaining a joined structure in which the first member and the second member are joined.

Injection molding joining is performed using, for example, an electric injection molding machine. Specifically, by inserting the first member into a mold installed in the molding machine and filling the mold with a molten resin, the second member can be molded to obtain a bonded structure.

Ultrasonic welding is performed by superimposing the first member and the second member via a joint and installing the first member and the second member on a device for ultrasonic welding. Ultrasonic welding is performed through a horn for ultrasonic welding to obtain a bonded structure.

Hot press bonding is performed by superimposing the first member and the second member via a joint and installing the first member and the second member on a device for hot pressing or a mold. Heat and pressure are applied from the second member side to join them to obtain a joined structure.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to the following Examples.

[Vertical peeling test]
FIG. 12 schematically shows the joint structure used in the vertical peeling test. The joint structure used in the vertical peeling test was obtained by joining so that the longitudinal direction of the first member 1 and the longitudinal direction of the second member were perpendicular to each other. At the time of joining the joined structure, the laser was irradiated from the second member side 2 while applying pressure from both sides of the first member 1 and the second member 2.

Further, FIG. 13 schematically shows a method of a vertical peeling test. Using an electromechanical universal tester 5900 (manufactured by Instron), the joint structure was pulled in a direction perpendicular to the joint surface (in the direction of the arrow shown as the tensile direction in FIG. 13). The test was terminated when the second member 2 or the joint interface was broken. In order to suppress the generation of moments, both ends of the second member 2 in the longitudinal direction were chucked with resin, and the tensile speed was set to 5 mm / min. ^{The joint strength (N / mm 2} = MPa) was determined by dividing the obtained load (N) by the area of the joint (25 mm × 2 mm). The numerical value of the joint strength was expressed as an average value obtained from 5 tests. Further, in the table, if the bonding strength is less than 3 MPa, it is indicated as ×, if it is 3 MPa or more, it is indicated as ◯, and if it is 10 MPa or more, it is indicated as ⊚.

[Shear strength test]
FIG. 14 schematically shows the joint structure used in the shear strength test. The joined structure used in the shear strength test was obtained by joining so that the longitudinal direction of the first member 1 and the longitudinal direction of the second member were parallel to each other. At the time of joining the joined structure, the laser was irradiated from the second member side 2 while applying pressure from both sides of the first member 1 and the second member 2.

Further, FIG. 15 schematically shows a method of shear strength test. In FIG. 15, the longitudinal direction of the first member and the second member is defined as the X-axis direction, and the direction perpendicular to the X-axis direction and perpendicular to the thickness direction of the first member and the second member is defined as the Y-axis direction. , The thickness direction of the first member and the second member is the Z-axis direction. The joint structure was pulled in the X-axis direction with respect to the joint using an electromechanical universal testing machine 5900 (manufactured by Instron). In order to suppress the generation of moments, a dummy plate having the same thickness as the sample plate was sandwiched and chucked, and the test was conducted at a tensile speed of 5 mm / min. The test was completed when the second member was broken or the joint interface was broken. The shear strength in the Y-axis direction was also measured in the same manner. The ratio of the shear strength in the X-axis direction to the shear strength in the Y-axis direction was expressed in the numerical range obtained from the five tests.

[Example 1]
The first member was produced by forming protrusions on the metal material SUS304 (50 mm × 25 mm, thickness 2 mm) using the fiber laser marker MX-Z2000H (manufactured by OMRON).

FIG. 11 schematically shows the laser processing portion 4 of the first member 1. The laser machined portion 4 was formed at one end of the first member 1 in the longitudinal direction. The area of the laser processing section 4 was 2 mm × 25 mm. The laser irradiation conditions at the time of forming the protrusions are as follows. Wavelength: 1062 nm, output: 3 W, frequency: 10 kHz, scanning speed: 400 mm / s, number of scans: 20 times, subpulse: 20 lines. The laser was irradiated so that the arrangement of the protrusions was in the shape of a quadrangle shown in FIG.

FIG. 16 represents an optical microscope image showing the protrusions according to the first embodiment. The protrusion had a shape in which the diameter of the cross section perpendicular to the height direction had a region where the diameter expanded from the tip of the protrusion toward the base, and then decreased.

The obtained metal work piece is superposed on a second member made of PMMA (Acrylite, manufactured by Mitsubishi Rayon) of the same size as the metal work piece, and then a metal is used to join the first member and the second member. A bonded structure was obtained by irradiating a semiconductor laser while applying pressure to the processed portion of the above. The laser irradiation conditions and pressurization conditions at the time of joining are as follows. Output: 24 W, irradiation diameter: 2 mm, scanning speed 30 mm / s, number of scans: 30 times, pressing force: 80 N.

[Example 2]
A bonded structure was obtained in the same manner as in Example 1 except that the laser irradiation conditions for forming the protrusions of the first member were changed as follows. Output: 6W, frequency: 10kHz, scanning speed 700mm / s, number of scanning: 30 times, 20 subpulses. FIG. 17 represents an optical microscope image showing the protrusions according to the second embodiment. The protrusion had a shape in which the diameter of the cross section perpendicular to the height direction had a region in which the diameter decreased from the tip of the protrusion toward the base, and then expanded.

[Example 3]
A bonded structure was obtained in the same manner as in Example 1 except that the laser irradiation conditions for forming the protrusions of the first member were changed as follows. Output: 6W, frequency: 10kHz, scanning speed: 980mm / s, number of scanning: 30 times, subpulse: 20 lines. FIG. 18 shows an optical microscope image showing the protrusions according to the third embodiment. The protrusion had a shape in which the diameter of the cross section perpendicular to the height direction had only a region where the diameter of the cross section was reduced from the tip to the base of the protrusion.

[Example 4]
A bonded structure was obtained in the same manner as in Example 1 except that the laser irradiation conditions for forming the protrusions of the first member were changed as follows. Output: 6W, frequency: 10kHz, scanning speed: 700mm / s, number of scanning: 20 times, subpulse: 20 lines. FIG. 19 shows an optical microscope image showing the protrusions according to the fourth embodiment. The protrusion had a shape in which the diameter of the cross section perpendicular to the height direction had only a region extending from the tip to the base of the protrusion.

[Example 5]
A bonded structure was obtained in the same manner as in Example 1 except that the laser irradiation conditions for forming the protrusions of the first member were changed as follows. Output: 1W, frequency: 10kHz, scanning speed: 400mm / s, number of scanning: 20 times, subpulse: 20 lines. FIG. 20 shows an optical microscope image showing the protrusions according to the fifth embodiment. Compared to Example 4, the protrusion had a shape in which the diameter of the cross section perpendicular to the height direction was close to constant from the tip to the base of the protrusion.

[Comparative Example 1]
A powder made of stainless steel, titanium, and boron carbide was sprayed onto the metal surface of the first member to form a cladding layer by a semiconductor laser. The irradiation conditions of the semiconductor laser are as follows. Wavelength: 970 nm, output: 1000 W, frequency: 1 kHz, duty: 70%, scanning speed: 30 mm / s. Joining with the second member was carried out in the same manner as in Example 1 to obtain a joined structure.

Table 1 shows the results of the vertical peeling test of Examples 1 to 5 and Comparative Example 1.

From Table 1, it was found that Examples 1 to 5 in which the aligned protrusions were integrally formed with the first member showed stronger bonding as compared with Comparative Example 1 produced by laser cladding.

[Example 6]
A bonded structure was obtained in the same manner as in Example 1 except that the resin of the second member was PA6.

[Example 7]
As the resin of the second member, a resin in which glass fiber (GF) was dispersed in PBT was used. The content of the glass fiber with respect to the whole resin was 30% by weight. Since this resin is difficult for the laser to pass through, the laser at the time of joining was irradiated from the back surface and the metal was heated to join the resin to obtain a bonded structure. The laser irradiation conditions at the time of joining are as follows. Output: 50 W, irradiation diameter: 2 mm, scanning speed: 30 mm / s, number of scans: 30 times, pressing force: 80 N. A bonded structure was obtained in the same manner as in Example 1 except for these matters.

[Example 8]
A bonded structure was obtained in the same manner as in Example 7 except that a resin (CFRTP) in which carbon fibers (CF) were dispersed in PA6 was used as the resin of the second member. The carbon fiber content with respect to the total CFRTP was 30% by weight.

The results of the vertical peeling test of Examples 1 and 6 to 8 are shown in Table 2. The results show only the broken members, not the joint strength numbers.

From Table 2, even when the type of resin was changed, the second member, not the joint, was destroyed.

[Example 9]
A bonded structure was obtained in the same manner as in Example 1 except that the laser scanning trajectory for forming the protrusions was appropriately adjusted and the protrusions were prepared in the arrangement shown in FIG.

[Example 10]
A bonded structure was obtained in the same manner as in Example 1 except that the laser scanning trajectory for forming the protrusions was appropriately adjusted and the protrusions were prepared in the arrangement shown in FIG.

Table 3 shows the results of the vertical peeling test and the shear strength test of Examples 1, 9 to 10 and Comparative Example 1.

From Table 3, Examples 1 and 9 to 10 in which the protrusions were aligned were superior in vertical peel strength to Comparative Example 1 in which the protrusions were arranged randomly, and the anisotropy of the shear strength could be suppressed. ..

One aspect of the present invention can be used for all devices that require, for example, metal-resin bonding or metal-resin bonding.

1 1st member 2 2nd member 3 Protrusion 4 Laser processing part 11 Laser irradiation part 12 Laser irradiation superimposition part 13 Laser non-irradiation part 21 Area where diameter expands 22 Area where diameter decreases

Claims (11)

The first member, which is a metal work piece with protrusions aligned on the surface,
A bonded structure including a second member containing a thermoplastic resin, which is bonded to the first member via the protrusion. The bonded structure according to claim 1, wherein the height of the protrusion is 15 to 200 μm. The bonded structure according to claim 1 or 2, wherein the width of the protrusion is 10 to 200 μm. The joint structure according to any one of claims 1 to 3, wherein the distance between the protrusions is 10 to 200 μm. The joint structure according to any one of claims 1 to 4, wherein the arrangement of the protrusions is at least one of a triangular shape, a quadrangular shape, and a hexagonal shape when viewed from the tip end side of the protrusions. 10. The joint structure described. The joint structure according to any one of claims 1 to 6, wherein the diameter of the cross section perpendicular to the height direction of the protrusion expands from the tip of the protrusion toward the base and then decreases. The joint structure according to any one of claims 1 to 6, wherein the diameter of the cross section perpendicular to the height direction of the protrusion decreases from the tip of the protrusion toward the base and then expands. The joint structure according to any one of claims 1 to 6, wherein the diameter of the cross section perpendicular to the height direction of the protrusion is reduced from the tip to the base of the protrusion. The joint structure according to any one of claims 1 to 6, wherein the diameter of the cross section perpendicular to the height direction of the protrusions expands from the tip to the base of the protrusions. The joint structure according to any one of claims 1 to 5, wherein the diameter of the cross section perpendicular to the height direction of the protrusion is constant from the tip to the base of the protrusion.

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