JP7255466B2 - METAL MEMBER FOR JOINING WITH RESIN COMPOSITION, METHOD FOR MANUFACTURING METAL-RESIN JOINTED BODY, AND METAL-RESIN JOINTED BODY - Google Patents

Description

The present disclosure relates to a metal member for bonding with a resin composition, a method for manufacturing a metal-resin bonded body, and a metal-resin bonded body.

Various methods have been studied for producing a joined body in which a resin and a metal member are joined without using an adhesive. However, since resin and metal, which are essentially dissimilar materials, have poor bonding strength, it is necessary to find ways to improve the bonding strength.

For example, in Patent Document 1, unevenness is formed on the surface of an aluminum shape body made of an aluminum alloy, and resin is allowed to enter the recesses of the unevenness and solidify, thereby joining the aluminum shape body and the resin molded body. A method for increasing power is described. According to Patent Document 1, by forming a protrusion projecting from a part of the recess to the inner side of the recess, or by further providing a recess or a protrusion inside the recess, the aluminum shaped body and the resin molded body are formed. It is said that the adhesion strength and airtightness of the film can be further enhanced.

Further, in Patent Document 2, the surface of an aluminum alloy base material is anodized to form nanopores, and the surface is corroded with an alkaline solution to form corrosion pores, whereby the aluminum alloy A method for increasing the bonding strength between a base material and a resin is described. According to Patent Document 2, the aluminum alloy base material after the above treatment has a structure in which a large number of nanopores are formed inside the corrosion pores.

Further, in Patent Document 3, a concave portion and a through hole penetrating from the bottom surface of the concave portion to the other surface are formed on one surface of a metal plate, the other surface is covered, and the through hole passes through the metal plate. It is described that the metal plate and the resin layer can be joined together regardless of the material by forming the resin layer filled up to the interior of the recess. Patent Document 3 describes that the metal recessed by the formation of the recess protrudes from the other surface on the opposite side.

JP 2011-121306 A Japanese Patent Publication No. 2015-509557 JP 2012-183705 A

As described in Patent Documents 1 to 3, many attempts have been made to process the surface of a metal member from the viewpoint of increasing the bonding strength between the resin composition and the metal member. In particular, if a structure capable of locking the resin is formed, such as the protrusions described in Patent Document 1 and the through holes and recesses described in Patent Document 3, the resin composition is less likely to separate from the metal member. It is expected that the bonding strength of

However, according to the findings of the present inventors, even with the methods described in Patent Documents 1 to 3, the bonding strength between the resin composition and the metal member is as high as expected, especially when the thickness of the metal member is large. did not rise to

An object of the present disclosure is to provide a metal member capable of increasing the bonding strength with a resin composition, a method for bonding a metal-resin bonded body in which the resin composition and the metal member are bonded, and a metal resin produced by the method. The object is to provide a conjugate.

The metal member for bonding with the resin composition according to one aspect includes a plurality of protrusions having different heights from the surface of the metal member, all of which protrude from the surface of the metal member to which the resin composition is bonded. and the plurality of protrusions are arranged so that the height from the surface of the metal member increases toward the downstream side with respect to the flow direction of the resin composition that flows in contact with the metal member during bonding. ing.

A method for manufacturing a metal-resin bonded body according to one aspect includes the steps of placing a metal member inside a mold, and injecting a resin composition into the inside of the mold in which the metal member is placed. . The arranged metal member has a plurality of protrusions having different heights from the surface of the metal member on the surface with which the injected resin composition contacts, and the plurality of protrusions are the injected resin composition. It is arranged so that the height thereof increases toward the downstream side with respect to the flow direction of the resin composition.

A metal-resin bonded body according to one aspect includes a metal member and a resin composition bonded to a surface of the metal member. The metal member has a plurality of protrusions having different heights from the surface of the metal member on the surface to which the resin composition is bonded, and the plurality of protrusions are in contact with the metal member during bonding. It is arranged so that the height becomes greater toward the downstream side with respect to the flowing direction of the resin composition that has flowed.

According to the present disclosure, a metal member that can further increase the bonding strength with a resin composition, a method for bonding a metal-resin bonded body in which the resin composition and the metal member are bonded, and a metal resin produced by the method A conjugate is provided.

FIG. 1 is a schematic perspective view showing a metal member for bonding with a resin composition, relating to the first embodiment. FIG. 2A is a schematic diagram showing how the metal member is placed in the mold in the step of bonding the resin composition to the metal member, and FIG. 2B is a schematic diagram showing how the mold is closed by moving the core. . 3A, 3B, 3C and 3D are schematic diagrams showing how the melted resin composition is injected into the mold from the gate in the step of bonding the resin composition to the metal member. FIG. 4 is a schematic diagram showing a metal-resin joined body in which a metal member and a solidified resin composition are joined together. FIG. 5 is a schematic diagram showing how, when the resin composition is solidified, it shrinks and solidifies from both sides of the protrusion so as to tighten the protrusion. FIG. 6 is a schematic diagram showing how the resin composition flows inside the mold in the step of bonding the resin composition to the metal member. FIG. 7 is a schematic perspective view showing a metal member for bonding with a resin composition, relating to the second embodiment. FIG. 8 is a schematic perspective view showing a metal member for bonding with a resin composition, relating to the third embodiment. FIG. 9 is a schematic perspective view showing a metal member for bonding with a resin composition, relating to the fourth embodiment. FIG. 10 shows the state of the metal member for bonding with the resin composition and the resin composition injected into the mold and flowing in contact with the metal member, according to the fifth embodiment. It is a schematic diagram.

A number of embodiments of the present disclosure will be described in detail below with reference to the drawings. In addition, the embodiment described below is an example, and the present invention is not limited to these embodiments.

[First embodiment]
FIG. 1 is a schematic perspective view showing a metal member for bonding with a resin composition, relating to the first embodiment.

As shown in FIG. 1 , metal member 100 is a plate-like member and has a plurality of protrusions 120 arranged on one surface 110 and protruding from surface 110 . One surface 110 is the surface to which the resin composition is bonded.

In the present embodiment, the plurality of protrusions 120 are a plurality of cylindrical protrusions independently arranged on the surface of the metal member 100 . The shape of the convex portion 120, which is cylindrical, is not limited, and may be columnar, triangular columnar, square columnar, hexagonal columnar, elliptical columnar, etc., pyramidal, truncated pyramid, inverted truncated cone (inverted tapered shape). ) or any other shape. In this specification, the term “cylindrical” means that the ratio of the minimum distance to the maximum distance among the distances connecting points on the outer periphery of the metal member 100 in a cross section along the surface 110 of the metal member 100 is 0.5 or more. It means a shape that is 1.0 or less.

The plurality of protrusions 120 are aligned in the flow direction of the resin composition that contacts the metal member 100 and flows along the surface 110 during bonding (in the direction of the white arrow in FIG. 1, hereinafter simply referred to as the "flow direction"). The shape and arrangement are such that the height from the surface of the metal member 100 (hereinafter also simply referred to as “height”) gradually increases along the . Specifically, with respect to the convex portion 120a arranged on the upstream side with respect to the flow direction, the convex portion 120b arranged on the downstream side with respect to the flow direction than the convex portion 120a has a height from the surface 110 of the metal member 100 is a higher convex portion. Similarly, with respect to the convex portion 120b, the convex portion 120c arranged on the downstream side in the flow direction with respect to the convex portion 120b has a higher height from the surface 110 of the metal member 100. As shown in FIG. Moreover, the convex portion 120 d arranged downstream of the convex portion 120 c in the flow direction has a higher height from the surface 110 of the metal member 100 .

In this specification, the height of the projections 120 from the surface of the metal member 100 is the height of the metal member 100 cut along an arbitrary plane parallel to the flow direction of the resin composition flowing inside the mold 200. , means the distance from the cut surface to the apex of the convex portion 120 .

2 and 3 are process diagrams showing how the resin composition is bonded to the metal member 100. FIG.

First, as shown in FIG. 2A, a metal member 100 is arranged in a mold 200. As shown in FIG. The mold 200 has a cavity 210 in which the metal member 100 is arranged, and a core 220 which is a movable part, and the core 220 is provided with a gate 230 for injecting the molten resin composition.

In addition, the metal member 100 is arranged such that the height of the convex portion 120 becomes higher toward the downstream side with respect to the direction (flow direction) in which the resin composition injected from the gate 230 flows along the surface of the metal member 100. It is made. Therefore, in the metal member 100 placed inside the mold 200, the height of the protrusions 120 located closer to the gate 230 is lower, and the height of the protrusions 120 farther from the gate 230 is higher. ing. The direction of the white arrow shown in FIG. 2A is the direction in which the height of the convex portion 120 increases, similar to the arrow shown in FIG.

The core 220 is then moved to close the mold 200, as shown in FIG. 2B. At this time, the inside of the mold may be heated.

Next, as shown in FIG. 3A, molten resin composition 300 is injected into mold 200 through gate 230 . Of the surfaces 110 of the metal member 100, the injected resin composition 300 first contacts the surface 110 located directly below the gate 230 in the injection direction.

As shown in FIGS. 3B and 3C, the injected resin composition 300 flows along the surface 110 of the metal member 100 and fills the inside of the mold 200 . The resin composition 300 is injected until the inside of the mold 200 is almost completely filled with the resin composition 300 as shown in FIG. 3D.

After that, the mold 200 is cooled to cool and solidify the resin composition 300, thereby forming a metal-resin bonded body 400 in which the metal member 100 and the solidified resin composition 300 are bonded together from the mold 200, as shown in FIG. You can take it out and get it. When the metal-resin bonded body 400 is removed from the mold 200 , the resin composition is cut near the exit of the gate 230 to be separated from the resin composition inside the gate 230 . At this time, the resin composition adhering to the metal-resin joined body 400 side after the cutting is removed by post-processing such as polishing, but it is very difficult to completely remove it. Such injection marks 410 remain on the surface of the solidified resin composition 300 .

Here, metal generally has high thermal conductivity. Therefore, when the injected resin composition 300 flows in FIGS. 3A to 3D, the heat of the resin composition 300 continues to be taken away by the metal member 100 . Therefore, as the resin composition 300 flows, the temperature decreases, the viscosity increases, and the fluidity decreases. The resin composition 300 with reduced fluidity may not be able to make close contact with the surface of the metal member 100 . When the resin composition 300 is cooled and solidified in this state, a gap is generated between the metal member 100 and the resin composition 300, and the resin composition 300 cannot be sufficiently bonded to the metal member 100. Hard to increase strength. In particular, the portion of the metal member 100 located farther from the gate 230 inside the mold 200 has a more pronounced reduction in the bonding strength due to the generation of voids due to the decrease in the temperature and fluidity of the resin composition 300. be.

Conventionally, it is known that increasing the thickness of the metal member makes it difficult to increase the bonding strength between the resin composition and the metal member. This is thought to be because, particularly when the thickness of the metal member 100 is large, the metal member 100 absorbs a large amount of heat, and thus the temperature and fluidity of the resin composition 300 described above are likely to decrease, resulting in the formation of voids. be done.

On the other hand, in this embodiment, the plurality of protrusions 120 of the metal member 100 act as heat retainers that retain heat received from the resin composition 300 . Therefore, the resin composition around the projections 120 can easily maintain a predetermined temperature and is less likely to lose its fluidity, so that it can be solidified after being in close contact with the surface of the projections 120, thereby generating voids. is considered difficult.

Further, in the present embodiment, as shown in FIG. 5, when the resin composition 300 is solidified, it shrinks and solidifies in the direction of the arrow in the figure so as to tighten the convex portion 120 from both sides of the convex portion 120. . Therefore, the resin composition 300 that is cooled and shrunk strongly adheres to the protrusions 120 .

The protrusions 120 increase the bonding strength between the solidified resin composition 300 and the metal member 100 by these actions.

On the other hand, although the convex portion 120 retains the heat received from the resin composition 300 , it also deprives the resin composition 300 of that amount of heat. Therefore, when the metal member 100 has a plurality of protrusions 120 on the surface 110, the resin composition 300 flows from the surface 110 on the flow path toward the downstream side with respect to the direction in which the resin composition 300 flows inside the mold 200 (flow direction). Since the heat is taken away from the resin composition 300 and the heat is taken cumulatively by the protrusions 120, the temperature of the resin composition 300 tends to be extremely lowered. Therefore, simply arranging a plurality of protrusions 120 cannot sufficiently suppress the decrease in bonding strength due to the decrease in fluidity on the downstream side with respect to the flow direction.

In the present embodiment, based on the new findings of the present inventors described above, the surface of the metal member 100 has The heights of the plurality of protrusions 120 are changed according to the positions on the 110 .

Specifically, the metal member 100 is arranged on the downstream side with respect to the flow direction, and the convex portion 120c and the convex portion 120d that come into contact with the resin composition 300 whose temperature has decreased are arranged on the upstream side. The height is made higher than the portion 120a and the convex portion 120b.

FIG. 6 is a schematic diagram showing how the resin composition 300 flows inside the mold 200. As shown in FIG. In order to facilitate understanding, FIG. 6 is displayed with a higher magnification in the height direction than other drawings.

As described above, since the resin composition 300 loses heat to the metal member 100 , the temperature tends to drop more easily on the side in contact with the metal member 100 , and the temperature is less likely to drop on the side away from the surface 110 of the metal member 100 . Therefore, the resin composition 300 flowing inside the mold 200 is cooled from the side of the resin composition 302 flowing near the surface 110 of the metal member 100 as it flows, and is separated from the surface 110 of the metal member 100. The side of the resin composition 306 flowing on the side is difficult to cool.

Therefore, in the present embodiment, the height of the protrusions 120 is increased toward the downstream side with respect to the flow direction of the resin composition 300 .

As a result, the resin composition 300 injected into the mold 200 flows on the side in contact with the surface 110 of the metal member 100, and the resin composition 302, which is the easiest to cool, first collides with the projections 120a having the lowest height. Then, the filling is performed so as to surround the periphery of the convex portion 120a. Next, the resin composition 303 flowing on the side farther from the surface 110 of the metal member 100 than the resin composition 302 collides with the protrusion 120b having the next lowest height. At this time, although the temperature of the resin composition 303 is lowered due to the flow, compared with the resin composition 302 flowing on the side closer to the surface 110 of the metal member 100, the temperature of the metal member 100 until reaching the convex portion 120b is reduced. Since the amount of heat transferred to the projection 120b is small, it is easy to maintain a predetermined temperature even when it collides with the projection 120b. Therefore, even when the resin composition 303 collides with the convex portion 120b, the resin composition 303 can easily maintain a predetermined fluidity, and can be easily filled so as to surround the convex portion 120b.

Similarly, the temperature of the resin composition 304 that collides with the projection 120c having the next highest height decreases as it flows, but the heat transfer to the metal member 100 is less, so that it collides with the projection 120c. It is easy to maintain a predetermined fluidity even when the liquid is filled, and it is easy to fill so as to surround the periphery of the convex portion 120c. In addition, although the temperature of the resin composition 305 that collides with the convex portion 120d having the next highest height decreases as it flows, the heat transfer to the metal member 100 is less, so that the resin composition 305 collides with the convex portion 120d. Even at times, it is easy to maintain a predetermined fluidity, and it is easy to fill so as to surround the periphery of the convex portion 120d. The temperature of the resin composition 305, which finally collides with the tallest projections, decreases as it flows, but the heat transfer to the metal member 100 is less, so even when it collides with the projections, It is easy to maintain a predetermined fluidity, and it is easy to fill so as to surround the periphery of the convex portion.

As a result, in the present embodiment, the resin composition 300 having a predetermined temperature (predetermined fluidity) collides with each convex portion 120 and fills the convex portion 120 so as to surround the circumference thereof. This suppresses a decrease in bonding strength due to a decrease in fluidity due to cooling of the resin composition 300 on the downstream side with respect to the flow direction.

In addition, in the present embodiment, the intervals between the convex portions 120 may be constant or may vary. For example, with the intention of improving the bonding strength due to the protrusions 120 retaining heat on the downstream side, the distance between the protrusions 120 is reduced toward the downstream side with respect to the flow direction (the protrusions 120 are densely arranged). ) may be used, or the distance between the convex portions 120 may be increased toward the downstream side with respect to the flow direction (convex 120 may be sparsely arranged). These are appropriately set according to the physical properties of the metal member 100 and the resin composition 300 (ease of heat transfer and fluidity of the resin composition), the temperature of the injected resin composition 300, the temperature of heating the mold 200, and the like. can do.

The metal-resin bonded body 400 (see FIG. 4) obtained in this way has the metal member 100 and the resin composition 300 bonded to the surface 110 of the metal member 100, and the metal member 100 and the resin composition A plurality of protrusions 120 are arranged on the surface 110 to which the 300 is joined. The plurality of protrusions 120 are arranged so that the closer they are to the injection mark 410 , the lower the height, and the higher the height is in the direction away from the injection mark 410 . In other words, the metal-resin bonded body 400 has a plurality of ridges on the surface 110 where the metal member 100 and the resin composition 300 are bonded, the height of which increases along the direction away from the injection mark 410 . It has a convex portion.

The resin composition 300 may be a fiber-reinforced resin composition containing reinforcing fibers 310 such as carbon fibers, glass fibers and cellulose nanofibers. Further, the reinforcing fibers 310 are easily oriented along the flow direction of the resin composition 300 when the resin composition 300 flows in the mold 200 .

According to the present embodiment described above, the bonding strength between the metal member and the resin composition can be increased even when the thickness of the metal member is particularly large.

[Second embodiment]
FIG. 7 is a schematic perspective view showing a metal member for bonding with a resin composition, relating to the second embodiment.

As shown in FIG. 7, metal member 700 is a plate-like member and has a plurality of protrusions 720 arranged on one surface 710 . One surface 710 is the surface to which the resin composition is bonded. This embodiment differs from the first embodiment only in the shape of the plurality of protrusions 720 . Therefore, only differences from the first embodiment will be described, and descriptions of overlapping parts will be omitted.

In this embodiment, the plurality of protrusions 720 are a plurality of bar-shaped protrusions arranged independently on the surface of the metal member 700 . Each rod-shaped projection extends in a direction different from the flow direction of the resin composition that contacts the metal member 700 and flows along the surface 710 at the time of bonding (the direction of the white arrow in FIG. 7). are placed along the In this embodiment, the plurality of protrusions 720 are spaced apart from each other so as to extend along the direction perpendicular to the flow direction (in the direction of the hatched arrow in FIG. 7).

The shape of the bar-shaped convex portion 720 is not limited, and may be any shape such as a triangular prism, a square prism, a hexagonal prism, or an elliptical prism. In this specification, the term “rod-like” means that the ratio of the minimum distance to the maximum distance among the distances connecting points on the outer periphery of the metal member 700 in a cross section along the surface 710 of the metal member 700 is less than 0.5. It means a shape that becomes

The plurality of protrusions 720 are shaped and arranged such that the height of the protrusions gradually increases along the flow direction of the resin composition 300 (the direction of the white arrow in FIG. 7). Specifically, with respect to the convex portion 720a arranged on the upstream side with respect to the flow direction, the convex portion 720b arranged downstream from the convex portion 720a with respect to the flow direction has a height from the surface 710 of the metal member 700. is a higher convex portion. Similarly, the convex portion 720c arranged downstream of the convex portion 720b in the flow direction has a higher height from the surface 710 of the metal member 700 than the convex portion 720b.

In the present embodiment, the convex portions 720b and 720c, which are arranged on the downstream side with respect to the flow direction of the resin composition 300 and come into contact with the resin composition 300 whose temperature has decreased, are arranged on the upstream side. The height from the surface of the metal member 100 is made higher than the portion 720a. As a result, the metal member 700 is filled with the resin composition 300 having a predetermined temperature (predetermined fluidity) colliding with the respective convex portions 720 to surround the respective convex portions 720, and The resin composition 300 shrinks and solidifies so as to tighten the protrusions 720 , thereby suppressing a decrease in bonding strength due to a decrease in fluidity due to cooling of the resin composition 300 on the downstream side in the flow direction.

In this embodiment, each projection 720 has, as side surfaces, a first surface 722 facing upstream with respect to the flow direction and a second surface 724 facing downstream with respect to the flow direction. When the resin composition 300 injected and in contact with the metal member 700 is cooled and shrinks, the protrusion 720 shrinks so as to tighten the first surface 722 and the second surface 724 more firmly. The bonding strength between the metal member 700 and the resin composition 300 can be further increased.

Also in this embodiment, the bonding strength between the metal member and the resin composition can be increased even when the thickness of the metal member is particularly large.

Moreover, in the present embodiment, since the area of the convex portion that is tightened when cooled and contracted can be increased, the bonding strength between the metal member and the resin composition can be further increased.

In addition, the plurality of protrusions 720 may be parallel to each other, or may be non-parallel and may extend in mutually shifted directions.

[Third embodiment]
FIG. 8 is a schematic perspective view showing a metal member for bonding with a resin composition, relating to the third embodiment.

As shown in FIG. 8 , the metal member 800 is a plate-like member and has a first projection 820 and a second projection 830 arranged on one surface 810 . One surface 810 is the surface to which the resin composition is bonded. This embodiment differs from the second embodiment only in the shape of the projections. Therefore, only differences from the second embodiment will be described, and descriptions of overlapping parts will be omitted.

In this embodiment, the metal member 800 includes a plurality of rod-shaped first projections 820a, 820b, 820c, and 820d, which are all arranged on the surface of the metal member 800. , a rod-shaped second protrusion 830a, a second protrusion 830b, a second protrusion 830c, and a second protrusion 830d connecting these protrusions.

Each rod-shaped first convex portion 820a, first convex portion 820b, first convex portion 820c, and first convex portion 820d contacts the metal member 800 at the time of joining, and the resin composition flowing along the surface 810 flows. They are arranged along the surface 810 so as to extend in a direction different from the direction (the direction of the white arrow in FIG. 8). In the present embodiment, the first convex portion 820a, the first convex portion 820b, the first convex portion 820c, and the first convex portion 820d are all arranged in a direction perpendicular to the flow direction (in the direction of the hatched arrow in FIG. 8). spaced apart from each other so as to extend along the

The plurality of first convex portions 820a, first convex portions 820b, first convex portions 820c, and first convex portions 820d are arranged along the flow direction of the resin composition (the direction of the white arrow in FIG. 8), and the metal member 800 It is shaped and arranged such that the height from the surface of the Specifically, with respect to the first convex portion 820a arranged on the upstream side with respect to the flow direction, the first convex portion 820b arranged on the downstream side with respect to the flow direction of the first convex portion 820a It is a convex part with a higher height. Similarly, with respect to the first convex portion 820b, the first convex portion 820c arranged on the downstream side with respect to the flow direction of the first convex portion 820b has a higher height than the first convex portion 820b. , with respect to the first protrusion 820c, the first protrusion 820d arranged downstream of the first protrusion 820c in the flow direction is a protrusion having a higher height.

Each rod-shaped second protrusion 830a, second protrusion 830b, second protrusion 830c, and second protrusion 830d extends in a direction different from the direction in which each first protrusion extends (indicated by a hatched arrow in FIG. 8). direction) along the surface 810 . In the present embodiment, the second convex portion 830a, the second convex portion 830b, the second convex portion 830c, and the second convex portion 830d all extend along the same direction (flow direction of the resin composition). They are spaced apart from each other.

The plurality of second convex portions 830a, second convex portions 830b, second convex portions 830c, and second convex portions 830d all have the same width (the width in the direction of the hatched arrow in FIG. 8) and the same width. arranged at intervals. In addition, the shape and arrangement of each second protrusion are not limited to these, and for example, the width of the second protrusion may be narrower toward the downstream side with respect to the flow direction.

In addition, the surfaces of the plurality of second protrusions 830a, 830b, 830c, and 830d in contact with the resin composition have a continuous height along the flow direction of the resin composition. The slope becomes higher. The heights of the first convex portion 820a, the first convex portion 820b, the first convex portion 820c, and the first convex portion 820d, which have different heights, are the second heights at the positions where the first convex portions 820 are arranged. It has the same height as the height of the convex portion 830 . In addition, the surface of each of the first protrusions 820 that contacts the resin composition is a sloping surface that is flush with the sloping surface of the second protrusion 830 . As a result, the metal member 800 has a shape in which no step is provided, thereby suppressing retention of the resin composition at the stepped portion.

On the other hand, from the viewpoint of more effectively improving the joint strength by tightening the first convex portion 820 with the resin composition, the plurality of second convex portions 830a, 830b, and 830c And the surface of the second convex portion 830d in contact with the resin composition may have a step whose height increases discontinuously along the flow direction of the resin composition.

In the present embodiment as well, the first convex portion 820c and the first convex portion 820d, which are arranged on the downstream side with respect to the flow direction of the resin composition and come into contact with the resin composition whose temperature has decreased, are arranged on the upstream side. The height from the surface of the metal member 100 is made higher than the first convex portion 820a and the first convex portion 820b. As a result, the metal member 800 is filled so that the resin composition having a predetermined temperature (predetermined fluidity) collides with each of the first protrusions 820 and surrounds each of the first protrusions 820 ( The resin composition enters into the hole formed by the first protrusion 820 and the second protrusion 830 and fills the inside of the hole), and the resin composition shrinks and solidifies so as to tighten the first protrusions 820. By doing so, it is possible to suppress a decrease in bonding strength due to a decrease in fluidity due to cooling of the resin composition on the downstream side with respect to the flow direction.

Further, in the present embodiment, each of the first convex portion 820a, the first convex portion 820b, the first convex portion 820c, and the first convex portion 820d has a first surface 822 facing upstream with respect to the flow direction and a and a second face 824 facing downstream with respect to. When the resin composition that is injected and contacts the metal member 800 is cooled and shrinks, the first convex portion 820 shrinks so as to tighten the first surface 822 and the second surface 824 more firmly. , the bonding strength between the metal member 800 and the resin composition can be further increased.

In addition, the plurality of second protrusions 830 may be parallel to each other, or may be non-parallel and may extend in mutually shifted directions. Moreover, the plurality of second protrusions 830 may extend in the same direction as the flow direction, or may extend in directions different from the flow direction.

Furthermore, in the present embodiment, when the resin composition that is injected and contacts the metal member 800 is cooled and shrinks, it can contract firmly so as to tighten the second convex portion 830, so that the metal member 800 and the resin composition It is possible to further increase the bonding strength with.

[Fourth embodiment]
FIG. 9 is a schematic perspective view showing a metal member for bonding with a resin composition, relating to the fourth embodiment.

As shown in FIG. 9 , the metal member 900 is a plate-like member and has a plurality of protrusions 920 arranged on one surface 910 . One surface 910 is the surface to which the resin composition is bonded. This embodiment differs from the first embodiment only in the shape of the convex portion 920 . Therefore, only differences from the first embodiment will be described, and descriptions of overlapping parts will be omitted.

In this embodiment, the plurality of protrusions 920 are a plurality of cylindrical protrusions arranged independently on the surface of the metal member 900 .

The plurality of projections 920 correspond to the flow direction of the resin composition that contacts the metal member 900 and flows along the surface 910 during bonding (the direction of the plurality of white arrows in FIG. ) are shaped and arranged in such a way that the height gradually increases along the

Specifically, the plurality of convex portions 920 are arranged radially with respect to the convex portion 920a arranged closest to the point P where the resin composition first contacts in the mold 200 and the point P , a higher projection 920b, a projection 920c and a projection 920d. The convex portion 920b, the convex portion 920c, and the convex portion 920d are shaped and arranged such that the farther from the point P, the higher the height.

In this embodiment as well, the convex portion 920c and the convex portion 920d which are arranged on the downstream side with respect to the flow direction of the resin composition and come into contact with the resin composition whose temperature has decreased are replaced by the convex portion 920a which is arranged on the upstream side. and the height of the protrusion 920b. As a result, the metal member 900 is filled so that the resin composition having a predetermined temperature (predetermined fluidity) collides with the respective convex portions 920 to surround the respective convex portions 920, and the respective convex portions 920 are filled. The resin composition shrinks and solidifies so as to tighten the portion 920, thereby suppressing a decrease in bonding strength due to a decrease in fluidity due to cooling of the resin composition on the downstream side with respect to the flow direction.

Therefore, in this embodiment as well, the bonding strength between the metal member and the resin composition can be increased even when the metal member has a large thickness.

In addition, in this embodiment, an example in which a plurality of independent cylindrical protrusions 920 are arranged radially is shown, but each protrusion may be an annular protrusion centering on the point P. , the annular protrusion may have cutouts formed at different positions.

[Fifth embodiment]
FIG. 10 shows the state of the metal member 1000 for bonding with the resin composition and the resin composition 300 injected into the mold and flowing in contact with the metal member 1000, according to the fifth embodiment. It is a schematic diagram showing.

In this embodiment, convex portion 1020 is punched from surface 1012 opposite to surface 1010 of metal member 1000 in contact with the resin composition, and has hollow portion 1022 inside.

According to the present embodiment, since the convex portion 1020 has the hollow portion 1022 filled with heat-insulating air, the heat insulating effect of the convex portion 1020 is enhanced. Therefore, the resin composition 300 around the projections 1020 is less likely to be cooled, and the generation of voids due to decreased fluidity is more significantly suppressed, and the bonding strength between the metal member 1000 and the resin composition 300 is further increased.

Note that the convex portion 1020 may be any projection described in the first to fourth embodiments. Moreover, all the convex portions 1020 of the metal member 1000 may have the hollow portions 1022 , or only some of the convex portions 1020 may have the hollow portions 1022 . For example, the protrusions on the upstream side with respect to the flow direction where the temperature of the resin composition is less likely to drop are not provided with hollow portions, and only the protrusions 1020 on the downstream side with respect to the flow direction where the temperature of the resin composition is more likely to drop are provided with hollow portions 1022. may be provided.

Moreover, the inside of the hollow portion 1022 may be filled with air, may be in a vacuum, or may be filled with a liquid having low heat conductivity.

Moreover, the hollow portion 1022 may be formed by a known method other than punching.

[Other embodiments]
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and can be modified and implemented as appropriate without departing from the scope of the present disclosure.

For example, in the first embodiment and the fourth embodiment described above, an example in which the plurality of protrusions are columnar having a single side surface has been described. Similarly, the convex portion may have a shape having a first surface and a second surface on the side surface.

In addition, it is preferable to form the plurality of protrusions in a reverse tapered shape from the viewpoint of increasing the bonding strength between the metal member and the resin composition.

Also, in each of the above-described embodiments, an example in which the metal member is plate-shaped has been described, but the metal member may be of any shape other than a plate-like shape. Moreover, the convex portion may be arranged only on one surface of the metal member, or may be arranged on a plurality of surfaces to which the resin composition is bonded. Moreover, the surface on which the convex portion is arranged may be a flat surface, or may be a surface other than a flat surface such as a curved surface.

Further, in each of the above-described embodiments, an example in which the melted resin composition is injected into the mold from one gate has been described, but the melted resin composition may be injected into the mold from a plurality of gates. . In this case, the metal member may have a plurality of protrusions whose height changes according to the distance from each gate, within the reach of the resin composition injected from each gate.

Also, the metal member may have two protrusions with different heights, but it is preferable to have three or more protrusions with different heights.

Also, the metal member may have micro-roughnesses on the order of nanometers to micrometers formed by methods such as laser processing, blasting, and chemical processing. In particular, in the present disclosure, since the protrusions are provided on the surface of the metal member, the fluidity of the resin composition around the protrusions is less likely to decrease. As a result, the resin composition can easily enter the inside of the micro-roughness (there is less chance for voids to form inside the micro-roughness), and the bonding strength between the metal member having the micro-roughness and the resin composition can be increased more easily.

According to the present disclosure, it is possible to further increase the bonding strength between the metal member and the resin composition. In particular, even when the thickness of the metal member is large, the bonding strength can be further increased, so it is expected that the applications of the metal-resin bonded body will be expanded.

100, 700, 800, 900, 1000 Metal member 110, 710, 810, 910, 1010 Surface 120, 120a, 120b, 120c, 120d, 720, 720a, 720b, 720c, 920, 920a, 920b, 920c, 920d, 1020 Projection 200 Mold 210 Cavity 220 Core 230 Gate 300, 302, 303, 304, 305, 306 Resin composition 310 Reinforcing fiber 400 Metal-resin joined body 410 Injection mark 722, 822 First surface 724, 824 Second surface 820, 820a , 820b, 820c, 820d first protrusion 830, 830a, 830b, 830c, 830d second protrusion 1012 surface 1022 cavity

Claims (8)

A metal member for bonding with a resin composition,
Both have a plurality of protrusions with different heights from the surface of the metal member protruding from the surface of the metal member to which the resin composition is bonded,
The plurality of protrusions are arranged so that the height from the surface of the metal member increases toward the downstream side with respect to the flow direction of the resin composition that flows in contact with the metal member during bonding,
The plurality of projections are a plurality of cylindrical projections arranged independently of each other, or a plurality of rod-shaped projections arranged so as to extend along a direction different from the flow direction. is
A metal member for bonding with a resin composition. 2. The metal for bonding to the resin composition according to claim 1 , having rod-shaped projections arranged to extend along the direction of flow or a direction different from the direction of flow, connecting the plurality of projections. Element. At least one of the plurality of protrusions has a first surface facing upstream with respect to the flow direction and a second surface different from the first surface facing downstream with respect to the flow direction. A metal member for bonding with the resin composition according to claim 1 or 2 , comprising: The metal member for bonding with a resin composition according to any one of claims 1 to 3 , wherein the plurality of protrusions have hollow portions inside. placing the metal member inside the mold;
a step of injecting a resin composition into the mold in which the metal member is arranged;
The arranged metal member has a plurality of protrusions with different heights from the surface of the metal member on the surface with which the injected resin composition contacts,
The plurality of protrusions are arranged so that the height thereof increases toward the downstream side with respect to the flow direction of the injected resin composition,
The plurality of projections are a plurality of cylindrical projections arranged independently of each other, or a plurality of rod-shaped projections arranged so as to extend along a direction different from the flow direction. is
A method for producing a metal-resin joined body. A metal-resin bonded body comprising a metal member and a resin composition bonded to the surface of the metal member,
The metal member has a plurality of protrusions having different heights from the surface of the metal member on the surface to which the resin composition is bonded,
The plurality of protrusions are arranged so that the height thereof increases toward the downstream side with respect to the flow direction of the resin composition that flows in contact with the metal member during bonding,
The plurality of protrusions are a plurality of cylindrical projection-shaped protrusions arranged independently from each other, or a plurality of protrusions arranged so as to extend along a direction different from the flow direction. is a bar-shaped protrusion-shaped protrusion of
Metal-resin joint. The resin composition has an injection mark,
The flow direction is a direction away from the injection mark,
The metal-resin joined body according to claim 6 . The resin composition is a fiber-reinforced resin composition containing reinforcing fibers,
The flow direction is the direction in which the reinforcing fibers are oriented,
The metal-resin joined body according to claim 6 or 7 .

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