Patent Description:
Inventions for manufacturing a composite molded body are known which includes continuously irradiating a surface of a metal molded body with a continuous-wave laser beam to thereby roughen the surface and form a porous structure, and then bonding it with a resin molded body or other metal molded body via an adhesive layer to thereby manufacture the composite molded body (see <CIT> (Patent Document <NUM>) and <CIT> (Patent Document <NUM>)). The adhesive layer is formed by an adhesive that has penetrated into the surface roughened porous structure section of the metal molded body, and it is thought that more complex pore structure results in increased bonding effect of the adhesive layer, and that for the same pore structures, increased pore depth results in greater bonding strength provided by the adhesive layer.

An object of the present invention is to provide a composite that can obtain higher bonding strength and durability by making the average maximum elevation difference in the pore depths of the porous structure section of the metal molded body be shallower than that of the prior art, and reducing variations in the pore depths (maximum elevation difference in the pore depths).

The present invention provides a composite formed of a metal molded body and an adhesive layer, wherein.

A length range of <NUM> is randomly selected at a maximum of ten locations in a surface area region of <NUM> × <NUM> (if less than <NUM> × <NUM>, then the total surface area region) of the porous structure section of the metal molded body, the maximum elevation difference of pores of a porous structure within the length range of <NUM> at the maximum of ten locations is measured from a cross-sectional SEM image, and an average value of the maximum elevation differences is determined.

The present invention also provides a method for manufacturing the above-mentioned composite, the method including:.

The present invention also provides a composite having an adhesive layer on a bonding surface of a first metal molded body and a second metal molded body, wherein.

A length range of <NUM> is randomly selected at a maximum of ten locations in surface area regions of <NUM> × <NUM> (if less than <NUM> × <NUM>, then the total surface area region) of the first porous structure section and the second porous structure section of the metal molded bodies, the maximum elevation difference of pores of a porous structure within the length range of <NUM> at the maximum of ten locations is measured from a cross-sectional SEM image, and an average value of the maximum elevation differences is determined.

The bonding strength of the composite of the present invention to other molded bodies can be increased, and durability of the bonding strength including water resistance and moisture resistance can be improved by reducing variation in the maximum elevation difference of the porous structure section formed in the metal molded body.

A composite (first composite) according to an embodiment of the present invention is a composite formed from a metal molded body and an adhesive layer. The first composite serves as a production intermediate of a second composite and a third composite according to an embodiment of the present invention described below.

The metal molded body of the first composite has a porous structure section formed in a surface layer part. The metal that can be used in the metal molded body is not particularly limited, and can be appropriately selected according to the application. For example, the metal thereof can be selected from iron, various stainless steels, aluminum, zinc, titanium, copper, brass, chrome plated steel, magnesium and alloys containing these (except stainless steel), and cermets such as tungsten carbide and chromium carbide. These metals can be subjected to surface treatments such as an alumite treatment or a plating treatment.

The shape and size of the metal molded body can be set according to the application. The porous structure section of the metal molded body has the same cross-sectional structure as that of the surface layer section after surface roughening as described in the inventions of Patent Documents <NUM> and <NUM>, and includes: stem pores having openings and formed in a thickness direction, opened pores made from branch pores formed in a direction different from that of the stem pores from an inner wall surface of the stem pores, and an internal space formed in the thickness direction and having no opening. The porous structure section also has a tunnel connection path connecting the opened pores to the internal space, and a tunnel connection path connecting the opened pores one another.

With the composite according to an embodiment of the present invention, the average maximum elevation difference of the porous structure section from the surface of the metal molded body, as measured by the below-described method, is in a range from <NUM> to <NUM>, and the range of the maximum elevation difference used as a basis for calculating the average maximum elevation difference is within ±<NUM>% when the average maximum elevation difference is defined as a reference.

The above-mentioned method for measuring the average maximum elevation difference is described with reference to <FIG> and <FIG>. <FIG> illustrates a state in which a portion of the surface of a metal molded body <NUM> is roughened to form a porous structure section <NUM>. It may be assumed that the cross-sectional structure of surface roughened porous structure section <NUM> is substantially the same if the surface roughening conditions are constant, and that there are no differences due to the position of the porous structure section <NUM>. Thus, a surface area region (measurement surface area region) <NUM> of <NUM> × <NUM> is optionally selected from amongst the entire porous structure section <NUM>, and images of cross-sectional structures in the measurement surface area region are captured at ten locations using a scanning electron microscope (SEM).

While <FIG> illustrates a porous structure section, this figure is for describing the measurement method and does not illustrate a specific aspect of the porous structure section described above. For each of the SEM images captured at ten locations, an elevation difference (Hmax) between a highest peak portion 20a and a lowest portion (bottom portion) <NUM> is measured for a length range of <NUM> length as illustrated in <FIG>, and then the Hmax average value (average maximum elevation difference) of the ten locations is determined. The highest peak portion 20a and other peak portions 20b to 20d indicate a state in which the metal molded body <NUM> melts and bulges. Note that the thickness of the surface layer part in an embodiment according to the present invention is the distance from the highest peak portion 20a to the bottom <NUM> of the deepest pore in <FIG>, and therefore the thickness of the surface layer part is the same as the maximum elevation difference Hmax.

If the roughened surface area is less than <NUM> × <NUM>, the entire roughened surface area is measured. If the roughened surface area is less than <NUM> × <NUM> and the measurement at ten very narrow locations is difficult, the measurement is implemented at from <NUM> to <NUM> locations. Even if the roughened surface area is extremely large, it is thought that as long as the surface roughening conditions are the same, there is no difference in the structure of the porous structure section, and therefore measurements can be implemented on any single <NUM> × <NUM> surface area region (measurement surface area region), and as necessary, two to five <NUM> × <NUM> surface area regions (measurement surface area regions) can be optionally selected and measured.

The average maximum elevation difference of the porous structure section <NUM> of the metal molded body <NUM> is in a range from <NUM> to <NUM>, preferably in a range from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, and even more preferably from <NUM> to <NUM>.

The maximum elevation difference that is the basis for calculating the average maximum elevation difference is within a range of ±<NUM>% when the average maximum elevation difference is defined as a reference (when the average maximum elevation difference is <NUM>, the range of the maximum elevation difference is from <NUM> to <NUM>), and is preferably within a range of ±<NUM>%, and more preferably within a range of ±<NUM>%.

As illustrated in <FIG>, the adhesive layer of the first composite is formed to cover at least the surface (peaks 20a to 20d) of the metal molded body <NUM> that includes the porous structure section <NUM>, and to correspond to the recessed and protruding shape of the porous structure section <NUM>. The adhesive layer may be formed as far as the surface of the metal molded body <NUM> outside the porous structure section <NUM> (the surface on which the porous structure section <NUM> is not formed).

The adhesive layer is in a state in which micro recesses and protrusions are formed, the micro recesses and protrusions corresponding to recesses and protrusions on the surface of the metal molded body <NUM> on which the porous structure section <NUM> is present, and preferably, the thickness of the adhesive layer is as uniform as possible, but a partially non-uniform thickness portion may be present. The thickness of the adhesive layer is preferably in the same range as the range of the average maximum elevation difference of the porous structure section <NUM> of the metal molded body <NUM> described above. The thickness of the adhesive layer and the average maximum elevation difference of the porous structure section <NUM> of the metal molded body <NUM> preferably have an upper limit of <NUM> or less because with such upper limit, the bonding force can be increased by uniformly maintaining the thickness of the adhesive layer at the bonding surface (adhering surface) between the first composite and another molded body when the first composite is bonded to the other molded body through the adhesive layer of the first composite, and durability is improved by preventing air bubbles from entering into the adhesive layer. When the lower limit of the thickness of the adhesive layer and the average maximum elevation difference of the porous structure section <NUM> of the metal molded body <NUM> is <NUM> or greater, the bonding force when the first composite is bonded to the other molded body through the adhesive layer of the first composite can be increased.

The adhesive that forms the adhesive layer is not particularly limited, and known adhesives such as thermoplastic resin-based adhesives, thermosetting resin-based adhesives, and rubber-based adhesives, as well as moisture-curable adhesives can be used.

Examples of thermoplastic resin-based adhesives include polyvinyl acetates, polyvinyl alcohols, polyvinyl formals, polyvinyl butyrals, acrylic adhesives, polyethylene, chlorinated polyethylene, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ethylene-ethyl acrylate copolymers, ethylene-acrylic acid copolymers, ionomers, chlorinated polypropylenes, polystyrenes, polyvinyl chlorides, plastisols, vinyl chloride-vinyl acetate copolymers, polyvinyl ethers, polyvinylpyrrolidone, polyamides, nylons, saturated amorphous polyesters, and cellulose derivatives.

Examples of thermosetting resin-based adhesives include urea resins, melamine resins, phenolic resins, resorcinol resins, epoxy resins, polyurethanes, and vinyl urethanes.

Examples of rubber-based adhesives include natural rubbers, synthetic polyisoprenes, polychloroprenes, nitrile rubbers, styrene-butadiene rubbers, styrene-butadiene-vinylpyridine terpolymers, polyisobutylene-butyl rubber, polysulfide rubbers, silicone RTV, rubber chlorides, rubber bromides, kraft rubbers, block copolymers, and liquid rubbers.

Examples of moisture-curable adhesives include cyanoacrylate-based instantaneous adhesives.

A second composite according to an embodiment of the present invention is obtained by integrating the first composite and a non-metal molded body through the adhesive layer of the first composite. As the non-metal molded body, a molded body selected from glass, ceramic, stone, rock, brick, concrete, mortar, resin, rubber, and wood, and a composite molded body formed from two or more types of the above-mentioned molded bodies can be used. In addition, the non-metal molded body may be an existing product made from the various materials described above. A non-metal molded body that has been subjected to a surface roughening treatment on the surface that is bonded with the adhesive layer of the first composite may be used according to the type of material. The surface roughening treatment on the non-metal molded body can be performed by sandblasting, surface roughening using a file, a chemical treatment, or the like depending on the type of material.

A third composite according to an embodiment of the present invention is a composite having an adhesive layer on a bonding surface between the first metal molded body and the second metal molded body.

The first composite 1a and the first composite 1b are both the same as the first composite described above. The first metal molded body and the second metal molded body use molded bodies made from different metals, but molded bodies made from the same metal can be used as necessary. The shape and size, etc. of the first metal molded body and the second metal molded body are not particularly limited and can be selected according to the application.

Next, a method for manufacturing the first composite according to an embodiment of the present invention will be described. First, the surface of the metal molded body <NUM> is continuously irradiated and roughened with laser light at an irradiation rate of <NUM>/sec or greater using a continuous-wave laser, and thereby a porous structure section is formed in a surface layer part. The method for continuous irradiation of laser light using a continuous-wave laser can be performed in the same manner as the methods described in Patent Documents <NUM> and <NUM>, but continuous irradiation of laser light is necessary to satisfy the requirements of (a) to (d) below. As a result of this surface roughening treatment, the average maximum elevation difference of the porous structure section from the surface of the metal molded body is in a range from <NUM> to <NUM>, and the range of the maximum elevation difference used as a basis for calculating the average maximum elevation difference is within ±<NUM>% when the average maximum elevation difference is defined as a reference.

The output of the laser is from <NUM> to <NUM> W, preferably from <NUM> to <NUM> W, more preferably from <NUM> to <NUM> W, and even more preferably from <NUM> to <NUM> W.

The spot diameter of the laser light is from <NUM> to <NUM>, preferably from <NUM> to <NUM>, and more preferably from <NUM> to <NUM>.

The energy density for irradiation with laser light is from <NUM> to <NUM> Mw/cm<NUM>, preferably from <NUM> to <NUM> Mw/cm<NUM>, and more preferably from <NUM> to <NUM> Mw/cm<NUM>. The energy density for irradiation with laser light is determined from the output (W) of the laser light, and the laser light (spot surface area (cm<NUM>) (π·[(spot diameter)/<NUM>]<NUM>) using the following equation: (Output of Laser Light)/(Spot Surface Area). The requirement (c) is calculated from the requirement (a) and the requirement (b). However, the requirement (c) is important in controlling the surface roughening state of the metal molded body, and therefore, when a portion exists at which the numeric value of the requirement (c) calculated from the numeric range of the requirement (a) and the numeric range of the requirement (b) falls outside the range described above, the numeric range of the above requirement (c) takes priority.

The number of repetitions for irradiation with laser light is from <NUM> to <NUM>, and preferably from <NUM> to <NUM>. The number of repetitions for irradiation with laser light is the total number of times of irradiation to form one line (groove) when the laser light is irradiated linearly. When the laser light is to be repeatedly irradiated in a single line, bi-directional irradiation and unidirectional irradiation can be selected. Bi-directional irradiation is a method in which, when a single line (groove) is to be formed, the line (groove) is irradiated from a first end part to a second end part with a continuous-wave laser, after which the line is irradiated from the second end part to the first end part with the continuous-wave laser, and then repeatedly irradiated with the continuous-wave laser from the first end part to the second end part and then from the second end part to the first end part. Unidirectional irradiation is a method of repeatedly irradiating the line (groove) with the continuous-wave laser in one direction from the first end part to the second end part.

The irradiation conditions of the laser light excluding the requirements (a) to (d) are as follows. The irradiation rate of the continuous-wave laser is preferably from <NUM> to <NUM>/sec, more preferably from <NUM> to <NUM>/sec, and even more preferably from <NUM> to <NUM>/sec. When linearly irradiating with the continuous-wave laser light, a spacing (line spacing) between adjacent irradiation lines (grooves formed by adjacent irradiation) is preferably from <NUM> to <NUM>, and more preferably from <NUM> to <NUM>. All line spacings may be the same, or some or all of the line spacings may be different from one another.

The wavelength is preferably from <NUM> to <NUM>, and more preferably from <NUM> to <NUM>.

The defocus distance is preferably from -<NUM> to +<NUM>, more preferably from -<NUM> to +<NUM>, and still more preferably from -<NUM> to +<NUM>. Laser irradiation may be performed with the defocus distance set to a constant value, or may be performed while changing the defocus distance. For example, when laser irradiation is performed, the defocus distance may be set to gradually decrease, or may be set to periodically increase and decrease.

A known continuous-wave laser can be used, and for example, a YVO<NUM> laser, a fiber laser (preferably a single-mode fiber laser), an excimer laser, a carbon dioxide laser, a UV laser, a YAG laser, a semiconductor laser, a glass laser, a ruby laser, a He-Ne laser, a nitrogen laser, a chelate laser, or a dye laser can be used. Of these, because of the increased energy density, a fiber laser is preferable, and a single-mode fiber laser is particularly preferable.

Next, an adhesive is applied to the porous structure section at which the surface of the metal molded body <NUM> was roughened in the previous step, and thereby an adhesive layer is formed on the porous structure section, and the first composite is obtained. When a thermosetting resin-based adhesive is used as the adhesive, it is held with an a prepolymer applied thereon. The surface of the adhesive layer is formed with minute recesses and protrusions corresponding to recesses and protrusions on the surface of the porous structure section.

A method for manufacturing the second composite according to an embodiment of the present invention will be described. The first composite is manufactured by the manufacturing method described above. Next, the adhering surface of the non-metal molded body that has been surface roughened as necessary is maintained in a state of being pressed against the adhesive layer of the first composite. When the adhesive layer is formed from a thermoplastic resin-based adhesive, as necessary, the adhesive layer can be heated and adhered in a softened state to the adhering surface of the non-metal molded body. Furthermore, when the adhesive layer is formed from a prepolymer of a thermosetting resin-based adhesive, the prepolymer is heated and cured by leaving it in a heated atmosphere after adhering.

A method for manufacturing the third composite (first embodiment and second embodiment) according to an embodiment of the present invention will be described.

A first metal molded body and a second metal molded body are each subjected to surface roughening in the same manner as the surface roughening with laser light in the manufacturing method of the first composite, and thereby first and second porous structure sections are formed. Next, an adhesive is applied onto the first porous structure section of the first metal molded body to form an adhesive layer, and thereby a first composite 1a is manufactured. Next, the adhesive layer of the first composite 1a molded body and the porous structure section of the second metal molded body are pressed against each other and adhered and integrated to thereby manufacture a third composite. When the adhesive layer is formed from a thermoplastic resin-based adhesive, as necessary, the adhesive layer can be heated and adhered in a softened state to the adhesive surface of the non-metal molded body. Furthermore, when the adhesive layer is formed from a prepolymer of a thermosetting resin-based adhesive, the prepolymer is heated and cured by leaving it in a heated atmosphere after adhering.

A first composite 1a formed from a first metal molded body and an adhesive layer, and a first composite 1b formed from a second metal molded body and an adhesive layer are manufactured in the same manner as the method for manufacturing the first composite. Next, the adhesive layer of the first composite 1a and the adhesive layer of the first composite 1b are pressed together and adhered and integrated to thereby manufacture a third composite. When the adhesive layer is formed from a thermoplastic resin-based adhesive, as necessary, the adhesive layer can be heated and adhered in a softened state to the adhesive surface of the non-metal molded body. Furthermore, when the adhesive layer is formed from a prepolymer of a thermosetting resin-based adhesive, the prepolymer is heated and cured by leaving it in a heated atmosphere after adhering.

The composite and the method for manufacturing the composite according to an embodiment of the present invention also include the preferred embodiments described below.

(<NUM>) A method for manufacturing the metal molded body (metal molded body that has been surface roughened) containing a porous structure section in (<NUM>) above.

(<NUM>) A composite molded body formed from the metal molded body (metal molded body that has been surface roughened) containing a porous structure section in (<NUM>) above and a molded body formed from another material (including on adhesive). The molded body formed from another material is selected from a thermoplastic resin molded body, a thermosetting resin molded body, an electron beam curable resin molded body, an elastomeric molded body, a rubber molded body, and a metal molded body formed from a metal that differs from that of the metal molded body (metal molded body that has been surface roughened) containing the porous structure section.

(<NUM>) A method for manufacturing the composite molded body in (<NUM>) above.

A composite molded body formed of a metal molded body and a resin molded body can be formed by integrating a resin molded body with a metal molded body (metal molded body that has been surface roughened) containing a porous structure section through, for example, a method described in <CIT>.

As the above-mentioned method for integration, either of the following methods can be used:.

When a thermosetting resin is used, the molding method is preferably one in which a resin is introduced into a porous structure section (pores, grooves, and/or tunnel connection paths) formed in a metal molded body by applying pressure or the like to a liquid or molten resin (prepolymer), and then the resin is thermally cured to thereby obtain a composite molded body. In addition to injection molding and compression molding, molding methods such as transfer molding can also be used.

When the compression molding method is applied, for example, a method can be used in which a metal molded body is arranged in a state with a bonding surface (a surface including the porous structure section) exposed in the mold frame (state in which the bonding surface is at the front side), and a thermoplastic resin, a thermoplastic elastomer, or a thermosetting resin (provided that the thermosetting resin is a prepolymer) is inserted therein, and then compressed. Note that when a thermosetting resin (prepolymer) is used in an injection molding method and a compression molding method, the resin is thermally cured by heating or the like in a subsequent process.

The composite molded body formed of a metal molded body and a rubber molded body can be obtained using, for example, the following method described in <CIT> in which a rubber molded body is integrated with a bonding surface (a surface including a porous structure section) of a metal molded body that has been surface roughened. The method of integrating the metal molded body and the rubber molded body is preferably a press molding method or a transfer molding method.

When the press molding method is applied, a portion including the bonding surface (the surface including the porous structure section) of the metal molded body irradiated with laser light is arranged in a mold, and an uncured rubber for forming the rubber molded body is pressed in a state of being heated and pressurized against the bonding surface (surface including the porous structure section) of the metal molded body, and then cooled, and the product is subsequently removed.

When the transfer molding method is applied, a portion including a bonding surface (a surface including a porous structure section) of a metal molded body irradiated with laser light is arranged in a mold, and an uncured rubber is injection molded inside the mold against the bonding surface (the surface including the porous structure section) of the metal molded body, after which heating and pressurization are performed to integrate the rubber molded body with the bonding surface (the surface including the porous structure section) of the metal molded body, and the integrated product is subsequently cooled, and then removed. Note that, depending on the type of rubber that is used, after the product has been removed from the mold, secondary heating (secondary curing) in an oven or the like can be added to remove primarily residual monomers.

A composite molded body of metal molded bodies made from different metals can be obtained using, for example, the following method described in <CIT> to integrate the metal molded bodies. A first metal molded body having a high melting point and that has been surface roughened is arranged inside a mold with the bonding surface (the surface containing the porous structure section) at the top. Next, for example, a well-known die casting method is applied, and a metal (for example, aluminum, aluminum alloy, copper, magnesium, and alloys including the same) having a melting point that is lower than that of the metal of the first metal molded body (for example, iron or stainless steel) is poured in a molten state into the mold and then cooled.

In each example, two aluminum plates (A5025) (length of <NUM>, width of <NUM>, thickness of <NUM>) <NUM> and a below-described laser device were used, and a surface roughening region (<NUM> x <NUM>) <NUM> that would form a porous structure section <NUM> illustrated in <FIG> was continuously irradiated and surface roughened with laser light under the conditions shown in Table <NUM>, and the porous structure section was formed.

Next, the two aluminum plates <NUM> of each example were each placed on a hot plate with the surface roughened portion (porous structure section) <NUM> oriented upward, and preheated (<NUM>, <NUM> minutes). Next, an adhesive (EP106NL, one-part epoxy adhesive for industrial use, available from Cemedine Co. ) was applied, without heating and curing, to the surface roughened section (porous structure section) <NUM> of the aluminum plate <NUM>, and a first composite according to an embodiment of the present invention was obtained. Next, as illustrated in <FIG>, in each example, the adhesive application surfaces (adhesive layers of the first composites) of the two aluminum plates <NUM> were overlapped with each other and fixed using a clip, and then held at <NUM> for <NUM> hour to cure the adhesive, and a third composite was manufactured.

As illustrated in <FIG>, the shear bonding strength was evaluated through a shearing test using the third composites of Examples <NUM>, <NUM>, and <NUM> and Comparative Example <NUM>. The shearing test was performed by fixing an adhered object (third composite) of the two aluminum plates using chucks <NUM> of a tester, with a stainless steel (SUS304) spacer <NUM> interposed between the chuck <NUM> and each aluminum plate <NUM>, as illustrated in <FIG>. Furthermore, the third composites of Examples <NUM>, <NUM>, and <NUM> and Comparative Example <NUM> were immersed in <NUM> hot water, and at <NUM> days and <NUM> days after immersion, shearing tests were performed as illustrated in <FIG> to evaluate the shear bonding strength. The results are shown in Table <NUM>.

Furthermore, after the test to measure the shear bonding strength, the third composites of Examples <NUM> to <NUM> and Comparative Example <NUM> were cut in a direction perpendicular to the adhering surface of the two aluminum plates <NUM> using an ultrasonic cutter, and SEM images of the cut surfaces were captured (Example <NUM> is illustrated in <FIG>, Comparative Example <NUM> is illustrated in <FIG>, and a comparison of Example <NUM> and Comparative Example <NUM> is illustrated in <FIG>). The average maximum elevation differences (average of ten locations) of Examples <NUM> and <NUM> and Comparative Example <NUM> were measured from <FIG>, <FIG>, and <FIG>, and the results are shown in Table <NUM>. Furthermore, the ranges of the maximum elevation differences when the average maximum elevation difference is defined as a reference are also shown in Table <NUM>. The SEM image of Example <NUM> was omitted, but was measured in the same manner.

In both <FIG> and <FIG>, the white portions indicate the porous structure section of the aluminum plate, and the material adhered thereon is the adhesive. <FIG> was captured at a magnification of <NUM> times, and <FIG> was captured at a magnification of <NUM> times, and even from a comparison of <FIG> and <FIG>, differences in the pore depths can be clearly confirmed. However, with the magnification of <NUM> times in <FIG>, the difference in pore depth is more pronounced. <FIG> is an SEM image of the cut surface of Example <NUM>, <FIG> is an SEM image of the cut surface of Comparative Example <NUM>, and both images are shown at the same scale. Circular to irregularly shaped black portions are observed in both <FIG>, but it was confirmed that these were air bubbles present in the adhesive layer between the two aluminum plates, and that the air bubbles in Example <NUM> (<FIG>) were much smaller than those in Comparative Example <NUM> (<FIG>). The results are shown in Table <NUM>.

From the common technical knowledge of a person skilled in the art, it is thought that as the pore depth of the porous structure section of the metal molded body used in the third composite increases, the shear bonding strength increases. However, as is clear from a comparison of Examples <NUM> to <NUM> and Comparative Example <NUM>, the shear bonding strength was around the same level regardless of the clear difference in the average maximum elevation difference.

Furthermore, from the results of the hot water immersion test, it was confirmed that for the third composites of Examples <NUM> to <NUM>, the decrease in shear bonding strength was small, and durability including water resistance and moisture resistance was high. Furthermore, the difference between the hot water immersion test results of Examples <NUM> to <NUM> and Comparative Example <NUM> is thought to be resulted from the effect of the size of the air bubbles (the outer diameter of each air bubble and the total volume of the air bubbles) remaining in the adhesive layer as described above. Note that in Examples <NUM> to <NUM>, it is thought that the reduction in the size of the air bubbles in the adhesive layer in this manner contributes to the smaller average maximum elevation difference of the pore depth and the ease of degassing.

The surface of an aluminum plate was roughened in the same manner as in Example <NUM> to form a porous structure section. Next, an adhesive (MOS7-<NUM> available from Konishi Co. ) was applied to a bonding surface (surface with the porous structure section) of the treated aluminum plate, a plate made from GF <NUM>% reinforced PA66 resin (Plastron PA66-GF60-<NUM> (L7): available from Daicel Polymer Ltd. ) was bonded thereto, and a composite molded body of an aluminum plate/PA66-GF60-<NUM> (L7) plate was thereby obtained.

Claim 1:
A composite comprising a metal molded body and an adhesive layer, wherein
the metal molded body has a porous structure section formed in a surface layer part;
the adhesive layer is formed in a portion that includes the porous structure section; and
an average of a maximum elevation difference in the porous structure section of the metal molded body measured according to the method described below is in a range from <NUM> to <NUM>, and a range of the maximum elevation difference used as a basis for calculating the average maximum elevation difference is within ±<NUM>% when the average maximum elevation difference is defined as a reference,
method for measuring the average maximum elevation difference:
a length range of <NUM> is randomly selected at a maximum of ten locations in a surface area region of <NUM> × <NUM> (if less than <NUM> × <NUM>, then the total surface area region) of the porous structure section of the metal molded body, the maximum elevation difference of pores of a porous structure within the length range of <NUM> at the maximum of ten locations is measured from a cross-sectional SEM image, and an average value of the maximum elevation differences is determined.