Composite member

Abstract

A composite member (1) has an inorganic layer (10) containing an inorganic substance containing at least one of a metal oxide and a metal hydroxide oxide. The composite member (1) has a resin layer (20) provided on a surface of the inorganic layer (10), containing a resin (21) and inorganic particles (22) dispersed in the resin (21) and directly bonded to the inorganic substance of the inorganic layer (10). A porosity in a cross section of the inorganic layer (10) is 20% or less, and a peak derived from a hydroxyl group is detected from the inorganic layer (10) when measured by infrared spectroscopy or X-ray diffraction.

Description

TECHNICAL FIELD

[0001] The present application relates to a composite member. BACKGROUND

[0002] In the past, a composite member in which a ceramic and a plastic are adhered via an adhesive has been known. However, even when a liquid adhesive is applied to the ceramic or the plastic, the ceramic and the plastic are adhered via the adhesive by applying a prescribed pressure, and it is difficult to obtain sufficient bonding strength.

[0003] Therefore, in Patent Document 1, a method is disclosed in which a liquid adhesive is solidified on the surface of a ceramic to form an adhesive layer, and then a molten resin is injected to the ceramic whose surface is covered with the adhesive layer. By this method, a composite in which the adhesive layer is interposed between the ceramic and the plastic can be manufactured.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-128975 SUMMARY

[0007] In the prior art, as the adhesive, a liquid adhesive in which polyvinyl acetate, polyvinyl alcohol, polybutylene terephthalate, dibutyl acetate, and an organic solvent are used as main components is used. However, even in the case where such an adhesive is used, when the adhesive layer deteriorates, the ceramic and the plastic can be peeled off.

[0008] The present application has been made in view of the problems of the prior art. Moreover, an object of the present application is to provide a composite member in which an inorganic layer and a resin layer are firmly bonded without interposition of an adhesive.

[0009] To solve the above problems, a composite member according to an aspect of the present application includes an inorganic layer containing an inorganic substance containing at least one of a metal oxide and a metal oxide hydroxide. The composite member includes a resin layer provided on a surface of the inorganic layer, containing a resin and inorganic particles dispersed in the resin and directly bonded to the inorganic substance of the inorganic layer. A porosity in a cross section of the inorganic layer is 20% or less, and a peak derived from a hydroxyl group is detected from the inorganic layer when measured by infrared spectroscopy or X-ray diffraction. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a schematic view that schematically shows one example of the composite member of the present embodiment.

[0011] Figure 2is a cross-sectional view schematically showing one example of the inorganic layer of the present embodiment.

[0012] Figure 3 is a cross-sectional view showing a case where the inorganic substance of the inorganic layer is directly fixed to the inorganic particles of the resin layer.

[0013] Figure 4 is a cross-sectional view showing a case where the inorganic substance of the inorganic layer is continuously and integrally combined with the inorganic particles of the resin layer.

[0014] Figure 5 is an SEM image obtained by observing the test sample of Example 1 at 500 times.

[0015] Figure 6 is an SEM image obtained by observing the test sample of Example 1 at 5000 times.

[0016] Figure 7 is an SEM image obtained by observing the test sample of Example 2 at 500 times.

[0017] Figure 8 is an SEM image obtained by observing the test sample of Example 2 at 5000 times.

[0018] Figure 9 is an SEM image obtained by observing the test sample of Comparative Example 1 at 500 times.

[0019] Figure 10 is an SEM image obtained by observing the test sample of Comparative Example 1 at 5000 times.

[0020] Figure 11 is a backscattered electron image showing position 1 in the test sample 1 of Example 1.

[0021] Figure 12 is an image obtained by binarizing the backscattered electron image of position 1 in the test sample 1 of Example 1.

[0022] Figure 13 is a backscattered electron image showing position 2 in the test sample 1 of Example 1.

[0023] Figure 14 is an image obtained by binarizing the backscattered electron image of position 2 in the test sample 1 of Example 1.

[0024] Figure 15 is a backscattered electron image showing position 3 in the test sample 1 of Example 1.

[0025] Figure 16 is an image obtained by binarizing the backscattered electron image of position 3 in the test sample 1 of Example 1.

[0026] Figure 17 is an infrared absorption spectrum of the inorganic layer, alumina, and aluminum hydroxide of Example 1.

[0027] Figure 18 is a graph showing an XRD pattern of the inorganic layer of Example 1 and an XRD pattern of alumina.

[0028] Figure 19 is a graph obtained by enlarging the XRD pattern of Figure 18 .

[0029] Figure 20 is a graph showing a fitting result of the XRD pattern of Example 1 and XRD patterns of boehmite, γ-alumina, and α-alumina registered in the ICSD (Inorganic Crystal Structure Database).

[0030] Figure 21 is a graph showing a fitting result of the XRD pattern of alumina and XRD patterns of α-alumina and boehmite registered in the ICSD.

[0031] Figure 22 is a TG curve of boehmite and aluminum hydroxide. DETAILED DESCRIPTION

[0032] Hereinafter, the composite member and the method for manufacturing the composite member of the present embodiment will be described in detail using the drawings. Note that the dimensional ratios of the drawings are exaggerated for the convenience of explanation and can be different from actual ratios.

[0033] [Composite member]

[0034] The composite member 1 of the present embodiment has an inorganic layer 10 and a resin layer 20 as shown in Figure 1 . The resin layer 20 is provided on the surface of the inorganic layer 10. The resin layer 20 can be provided on only one face of the inorganic layer 10, or can be provided on both faces of the inorganic layer 10.

[0035] (Inorganic layer 10)

[0036] The inorganic layer 10 of the present embodiment can contain a plurality of particles 11, for example, as shown in Figure 2 . The inorganic layer 10 can be formed by the particles 11 of inorganic substance binding to each other.

[0037] The inorganic layer 10 can contain a binding portion 12 that binds each of the plurality of particles 11. The inorganic layer 10 can have a portion in which each of the plurality of particles 11 is directly bound without the binding portion 12. The binding portion 12 can cover a part of the surface of each of the plurality of particles 11, or can cover the entire surface.

[0038] The inorganic layer 10 contains an inorganic substance. The inorganic substance can be contained in at least any one of the plurality of particles 11 and the binding portion 12. That is, the inorganic substance can be contained in any one of the plurality of particles 11 or the binding portion 12, or can be contained in both the plurality of particles 11 and the binding portion 12.

[0039] The inorganic substance contained in the inorganic layer 10 contains at least one of a metal oxide and a metal oxyhydroxide. That is, the inorganic substance can contain any one of a metal oxide or a metal oxyhydroxide, or can contain both a metal oxide and a metal oxyhydroxide. The metal oxide is preferably a compound in which only oxygen is bonded to a metal element.

[0040] The at least one of the metal oxide and the metal oxyhydroxide preferably contains at least one metal element selected from the group consisting of an alkali metal, an alkaline earth metal, a transition metal, a base metal, and a semimetal. In this specification, the alkaline earth metal includes beryllium and magnesium in addition to calcium, strontium, barium, and radium. The base metal includes aluminum, zinc, gallium, cadmium, indium, tin, mercury, thallium, lead, bismuth, and polonium. The semimetal includes boron, silicon, germanium, arsenic, antimony, and tellurium. Among them, the inorganic substance preferably contains at least one metal element selected from the group consisting of zinc, aluminum, and magnesium. The inorganic substance containing these metal elements can easily form the binding portion 12 derived from the inorganic substance by the pressure heating method as described later.

[0041] The metal oxide can also contain at least one selected from the group consisting of, for example, zinc oxide, magnesium oxide, and a composite of zinc oxide and magnesium oxide. With such a metal oxide, the inorganic layer 10 having high durability can be obtained.

[0042] The metal oxyhydroxide can also contain, for example, aluminum oxyhydroxide. As the aluminum oxyhydroxide, boehmite represented by the composition formula of AIOOH can be cited. The boehmite is not dissolved in water and hardly reacts with acids and bases at normal temperature, and thus has high chemical stability. Further, the boehmite has the following characteristics: the dehydration temperature thereof is as high as about 500°C, and thus the heat resistance thereof is also excellent. In addition, the boehmite has a specific gravity of about 3.07, and thus in the case where the inorganic layer 10 contains the boehmite, the inorganic layer 10 having light weight and excellent chemical stability can be obtained.

[0043] In the case where the inorganic substance included in the inorganic layer 10 is boehmite, the particles 11 can be particles including only a boehmite phase, or can be particles including a mixed phase of boehmite and aluminum oxide or aluminum hydroxide other than boehmite. For example, the particles 11 can also be particles in which a phase including boehmite is mixed with a phase including gibbsite (Al(OH)3). Adjacent particles 11 are preferably bonded via at least one of an oxide and an oxyhydroxide of aluminum. That is, the particles 11 are preferably not bonded by an organic binder including an organic compound, nor by an inorganic binder including an inorganic substance other than the oxide and the oxyhydroxide of aluminum. Note that in the case where adjacent particles 11 are bonded via at least one of an oxide and an oxyhydroxide of aluminum, the oxide and the oxyhydroxide of aluminum can be crystalline or amorphous.

[0044] In the case where the inorganic layer 10 includes boehmite, the proportion of the boehmite phase is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 70% by mass or more. By increasing the proportion of the boehmite phase, it is possible to obtain an inorganic layer 10 that is lightweight and has excellent chemical stability and heat resistance. Note that the proportion of the boehmite phase in the inorganic layer 10 can be found by performing Rietveld analysis after measuring the X-ray diffraction pattern of the inorganic layer 10 using an X-ray diffractometer.

[0045] In the case where the inorganic substance included in the inorganic layer 10 is boehmite, the bonding portion 12 can also include a boehmite phase. In the case where the bonding portion 12 includes a boehmite phase, the plurality of particles 11 can also include aluminum nitride. Aluminum nitride has the characteristics of having a large resistance and a high insulating resistance, and further exhibits a very high thermal conductivity as a ceramic material. The plurality of particles 11 can also not be bonded by an organic binder including an organic compound, nor by an inorganic binder other than the boehmite phase. Furthermore, as described below, the inorganic layer 10 can be formed by heating a mixture of a powder of an inorganic substance and water while applying pressure, and it is not necessary to use a reaction accelerator or the like. Thus, the inorganic layer 10 does not have impurities derived from an organic binder and an inorganic binder, and a reaction accelerator, and thus can maintain the original characteristics of aluminum nitride and boehmite.

[0046] The inorganic substance more preferably contains at least one of oxides and oxyhydroxides of the above metal elements as a main component. That is, the inorganic substance preferably contains 50 mol% or more of at least one of oxides and oxyhydroxides of the above metal elements, and more preferably contains 80 mol% or more. Further, the inorganic layer 10 also preferably contains at least one of oxides and oxyhydroxides as a main component. That is, the inorganic layer 10 preferably contains 50 mol% or more of at least one of oxides and oxyhydroxides, and more preferably contains 80 mol% or more.

[0047] The inorganic substance contained in the inorganic layer 10 is preferably a polycrystal. By the inorganic substance contained in the inorganic layer 10 being a polycrystal, a durable inorganic layer 10 can be obtained compared to the case where the inorganic substance is amorphous. It can also be that the particles 11 of the inorganic substance are crystalline particles, and the inorganic layer 10 is an inorganic layer in which a large number of the particles 11 are aggregated. Note that the particles 11 of the inorganic substance are more preferably crystalline particles containing at least one metal element selected from the group consisting of alkali metals, alkaline earth metals, transition metals, base metals, and semimetals. Further, the particles 11 of the inorganic substance are preferably crystalline particles containing at least one of oxides and oxyhydroxides of the above metal elements. The particles 11 of the inorganic substance are more preferably crystalline particles containing at least one of oxides and oxyhydroxides of the above metal elements as a main component.

[0048] The inorganic substance contained in the inorganic layer 10 preferably does not contain a hydrate of a calcium compound. The calcium compound referred to here is tricalcium silicate (alite, 3CaO-SiO2), dicalcium silicate (belite, 2CaO-SiO2), calcium aluminate (3CaO-Al203), calcium ferricaluminate (4CaO-Al203-Fe203), calcium sulfate (CaSO4-2H2O). In the case where the inorganic substance contained in the inorganic layer 10 contains a hydrate of the above calcium compound, the porosity in the cross section of the inorganic layer 10 can exceed 20% and the strength can decrease. Therefore, the inorganic substance preferably does not contain a hydrate of the above calcium compound. Further, the inorganic substance contained in the inorganic layer 10 preferably also does not contain phosphoric acid cement, zinc phosphate cement, and calcium phosphate cement. By the inorganic substance not containing these cements, the porosity in the cross section of the inorganic layer 10 decreases, and thus the mechanical strength can be improved.

[0049] The average particle diameter of the plurality of particles 11 is not particularly limited. The average particle diameter of the particles 11 is preferably 300 nm to 50 μm, more preferably 300 nm to 30 μm, and further preferably 300 nm to 20 μm. By setting the average particle diameter of the particles 11 of the inorganic substance within this range, the particles 11 are firmly bonded to each other, and the strength of the inorganic layer 10 can be improved. Note that, in this specification, as the value of the "average particle diameter", unless otherwise specified, the value calculated as the average of the particle diameters of the particles observed in several to several tens of fields of view using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM) is used.

[0050] The shape of the particles 11 of the inorganic substance is not particularly limited, and can be, for example, spherical. Alternatively, the particles 11 can be whisker-shaped (needle-shaped) particles or scale-shaped particles. The whisker-shaped particles or scale-shaped particles have an increased contact with other particles as compared to spherical particles, and the strength of the inorganic layer 10 is easily improved. Thus, by using such a shape of particles as the particles 11, the strength of the inorganic layer 10 as a whole can be improved.

[0051] Here, the inorganic substance contained in the inorganic layer 10 preferably substantially does not contain a hydrate. In this specification, the "inorganic substance substantially does not contain a hydrate" means that the inorganic substance does not intentionally contain a hydrate. Thus, even when a hydrate is mixed as an inevitable impurity in the inorganic substance, the condition that the "inorganic substance substantially does not contain a hydrate" is satisfied. Note that boehmite is not included in the hydrate in this specification because it is a metal oxyhydroxide.

[0052] The inorganic layer 10 is preferably composed of a group of particles of an inorganic substance. That is, it is preferable that the inorganic layer 10 be composed of a plurality of particles 11 containing an inorganic substance, and that the inorganic layer 10 be formed by the particles 11 of the inorganic substance being bonded to each other. At this time, the particles 11 can be in a state of point contact with each other, or can be in a state of surface contact in which the particle surfaces of the particles 11 are in contact with each other.

[0053] The bonding portion 12 preferably contains an amorphous inorganic compound. Specifically, the bonding portion 12 can be a portion containing only an amorphous inorganic compound, or can be a portion in which an amorphous inorganic compound and a crystalline inorganic compound are mixed. Alternatively, the bonding portion 12 can be a portion in which a crystalline inorganic compound is dispersed in an amorphous inorganic compound. In the case where an amorphous inorganic compound and a crystalline inorganic compound are mixed, the amorphous inorganic compound and the crystalline inorganic compound can have the same chemical composition, or can have different chemical compositions from each other.

[0054] The particle 11 and the bonding portion 12 of the inorganic substance preferably contain the same metal element selected from at least one of the group consisting of alkali metal, alkaline earth metal, transition metal, base metal, and semi-metal. That is, the inorganic substance contained in the particle 11 and the amorphous inorganic substance contained in the bonding portion 12 preferably contain at least the same metal element. The inorganic substance contained in the particle 11 and the amorphous inorganic substance contained in the bonding portion 12 can have the same chemical composition or different chemical compositions. Specifically, in the case where the metal element is zinc, the inorganic substance contained in the particle 11 and the amorphous inorganic substance contained in the bonding portion 12 can both be zinc oxide (ZnO). Alternatively, the inorganic substance contained in the particle 11 can be ZnO, but the amorphous inorganic substance contained in the bonding portion 12 can be a zinc-containing oxide other than ZnO.

[0055] The metal oxide contained in both the particle 11 and the bonding portion 12 is preferably at least one selected from the group consisting of zinc oxide, magnesium oxide, and a composite of zinc oxide and magnesium oxide. By using these metal oxides, the bonding portion 12 can be formed by a simple method, as described later.

[0056] The porosity in the cross section of the inorganic layer 10 is 20% or less. That is, in the case where the cross section of the inorganic layer 10 is observed, the average value of the proportion of pores per unit area is 20% or less. In the case where the porosity is 20% or less, cracks in the inorganic layer 10 that start from pores can be suppressed, and thus the bending strength of the composite member 1 can be improved. Note that the porosity in the cross section of the inorganic layer 10 is preferably 15% or less, more preferably 10% or less, and further preferably 5% or less. The smaller the porosity in the cross section of the inorganic layer 10, the more cracks that start from pores can be suppressed, and thus the strength of the composite member 1 can be improved.

[0057] In the present specification, the porosity can be calculated as follows. First, the cross section of the inorganic layer 10 is observed, and pores and non-pores are distinguished. Then, the area of a unit area and the area of pores in the unit area are measured, and the proportion of pores per unit area is calculated. After the proportion of pores per unit area is calculated at a plurality of sites, the average value of the proportion of pores per unit area is set as the porosity. Note that, in the observation of the cross section of the inorganic layer 10, an optical microscope, a scanning electron microscope (SEM), or a transmission electron microscope (TEM) can be used. Furthermore, the area of a unit area and the area of pores in the unit area can be measured by binarizing an image obtained by microscope observation.

[0058] The size of the pores present inside the inorganic layer 10 is not particularly limited, but is preferably as small as possible. Smaller pore sizes can suppress cracks originating from pores, thus improving the strength of the inorganic layer 10 and consequently its machinability. It should be noted that the pore size of the inorganic layer 10 is preferably 5 μm or less, more preferably 1 μm or less, and even more preferably 100 nm or less. The size of the pores present inside the inorganic layer 10 can be determined, similar to the porosity mentioned above, by observing the cross-section of the inorganic layer 10 under a microscope.

[0059] Regarding composite component 1, when measured by infrared spectroscopy or X-ray diffraction, a peak originating from hydroxyl groups was detected from the inorganic layer 10. Specifically, if the peak area of ​​the aforementioned peak is greater than the background level, it can be determined that the aforementioned peak was detected from the inorganic layer 10. The peak area also varies depending on the type of material constituting the inorganic layer 10, but can be calculated using the method implemented in the embodiments described later. When measured by infrared spectroscopy, the peak area can be 2 cm⁻². -1 The above can also be 3cm. -1 The above applies. When measured by X-ray diffraction, the peak area can be above 1000°(2θ)·cps, above 2000(2θ)·cps, or above 4000°(2θ)·cps.

[0060] If the inorganic layer 10 is heated at a high temperature, the hydroxyl groups will detach. Therefore, in order to detect the aforementioned peaks in the inorganic layer 10, it is necessary to heat the inorganic layer 10 at a low temperature. The inorganic layer 10, as described below, can be obtained by heating the raw material at a low temperature of 50–300°C while applying pressure, thus allowing the detection of peaks originating from hydroxyl groups. Furthermore, since the inorganic layer 10 can be obtained by heating and pressurizing at a low temperature, components with low heat resistance can be added to the inorganic layer 10, for example. Organic substances such as resin particles and pigments can be added to the inorganic layer 10, for example.

[0061] The thickness t1 of the inorganic layer 10 is not particularly limited, and can be set to 50 μm or more, for example. The composite component 1 of this embodiment is formed by a pressure heating method as described below. Therefore, a thick inorganic layer 10 can be easily obtained. It should be noted that the thickness t1 of the inorganic layer 10 can be set to 1 mm or more, or 1 cm or more. The upper limit of the thickness t1 of the inorganic layer 10 is not particularly limited, and can be set to 50 cm, for example.

[0062] (Resin layer 20)

[0063] Resin layer 20 Figure 1As shown, it contains resin 21 and inorganic particles 22. The inorganic particles 22 are dispersed within the resin 21. Therefore, the resin 21 covers at least a portion of the surface of the inorganic particles 22. The resin 21 may cover only a portion of the surface of the inorganic particles 22 or cover the entire surface of the inorganic particles 22.

[0064] Inorganic particles 22 such as Figure 3 As shown, the inorganic particles 22 directly adhere to the inorganic material of the inorganic layer 10. By directly adhering the inorganic particles 22 to the inorganic material of the inorganic layer 10, the adhesion between the inorganic layer 10 and the resin layer 20 is increased, thus preventing peeling between the inorganic layer 10 and the resin layer 20. It should be noted that in this embodiment, the so-called adhesion refers to the contact between the inorganic particles 22 and the inorganic layer 10, and the inorganic particles 22 contribute to increasing the adhesion between the inorganic layer 10 and the resin layer 20. Therefore, the so-called adhesion in this embodiment also includes the contact between the inorganic particles 22 and the inorganic layer 10, but the inorganic particles 22 and the inorganic material contained in the inorganic layer 10 are not continuously and integrally bonded.

[0065] It should be noted that, as Figure 4 As shown, the inorganic particles 22 are preferably integrally bonded to the inorganic material contained in the inorganic layer 10. Through this bonding, the inorganic particles 22 and the inorganic material contained in the inorganic layer 10 are firmly bonded to the resin layer 20 via the inorganic material and the inorganic particles 22. Therefore, the adhesion between the inorganic layer 10 and the resin layer 20 is increased, thereby further suppressing the peeling of the inorganic layer 10 and the resin layer 20.

[0066] Resin 21 can be a thermosetting resin or a thermoplastic resin. Thermoplastic resins preferably include, for example, at least one resin selected from the group consisting of polyacrylate, ethylene-vinyl acetate copolymer, olefin resins, polyvinyl butyral, polyethylene terephthalate, and polyimide. Thermosetting resins preferably include, for example, at least one resin selected from the group consisting of polyacrylate, epoxy resin, polyurethane, and polyimide.

[0067] Inorganic particles 22 may include, for example, inorganic substances. The inorganic substances contained in inorganic particles 22 may also include at least one of metal oxides and metal oxide hydroxides. That is, the inorganic substances may include either metal oxides or metal oxide hydroxides, or both. The metal oxide is preferably a compound formed by bonding oxygen only to a metal element. At least one of the metal oxides and metal oxide hydroxides preferably contains at least one metallic element selected from the group consisting of alkali metals, alkaline earth metals, transition metals, base metals, and half-metals.

[0068] The inorganic particles 22 preferably contain a metal element contained in the inorganic substance of the inorganic layer 10. By the inorganic substance contained in the inorganic layer 10 containing the same metal element as the inorganic particles 22 contained in the resin layer 20, the reactivity of the inorganic substance of the inorganic layer 10 becomes high. Therefore, the inorganic substance of the inorganic layer 10 and the inorganic particles 22 are strongly combined, and the adhesion of the inorganic layer 10 and the resin layer 20 can be further improved. The inorganic substance of the inorganic layer 10 and the inorganic substance contained in the inorganic particles 22 can be the same in chemical composition, or can be different. Specifically, in the case where the metal element is zinc, the inorganic substance of the inorganic layer 10 and the inorganic substance contained in the inorganic particles 22 can both be zinc oxide (ZnO). Alternatively, the inorganic substance of the inorganic layer 10 can be ZnO, but the inorganic substance contained in the inorganic particles 22 can be a zinc-containing oxide other than ZnO.

[0069] The inorganic particles 22 preferably have a hydroxyl group. The inorganic particles 22 can contain, for example, an oxide such as silicon dioxide and aluminum oxide, and a hydroxide such as aluminum hydroxide. By the inorganic particles 22 having a hydroxyl group, the inorganic particles 22 and the inorganic substance of the inorganic layer 10 are strongly bonded by a hydrogen bond. Therefore, the adhesion of the inorganic layer 10 and the resin layer 20 can be further improved. Note that whether the inorganic particles 22 have a hydroxyl group can be determined by infrared spectroscopy or X-ray diffraction as described above.

[0070] The average particle diameter of the inorganic particles 22 is not particularly limited. The average particle diameter of the inorganic particles 22 is preferably 300 nm to 50 μm, more preferably 300 nm to 30 μm, and further preferably 300 nm to 20 μm. By the average particle diameter of the inorganic particles 22 being within this range, the mechanical strength of the resin layer 20 is not greatly impaired, and the adhesive strength of the inorganic layer 10 and the resin layer 20 can be improved.

[0071] The shape of each of the inorganic particles 22 is not particularly limited, and can be, for example, spherical. In addition, each of the inorganic particles 22 can be a whisker-like (needle-like) particle or a flake-like particle.

[0072] The content ratio of the inorganic particles 22 with respect to the resin layer 20 is preferably 10 vol% to 70 vol%. In the case where the content ratio of the inorganic particles 22 is 10 vol% or more, the bonding area of the inorganic substance contained in the inorganic layer 10 with the inorganic particles 22 contained in the resin layer 20 becomes large, and thus the adhesion of the inorganic layer 10 to the resin layer 20 becomes high. In addition, in the case where the content ratio of the inorganic particles 22 is 70 vol% or less, the proportion of the resin 21 in the resin layer 20 becomes large, and thus the composite member 1 in which the characteristics of the resin 21 are maintained can be formed. The content ratio of the inorganic particles 22 is more preferably 15 vol% or more, and further preferably 20 vol% or more. In addition, the content ratio of the inorganic particles 22 is more preferably 50 vol% or less, and further preferably 30 vol% or less.

[0073] The thickness t2 of the resin layer 20 is not particularly limited, and can be set to 50 μm or more, for example. Note that the thickness t2 of the composite member 1 can be set to 1 mm or more, or can be set to 1 cm or more. The upper limit of the thickness t2 of the composite member 1 is not particularly limited, and can be set to 50 cm, for example.

[0074] The shape of the composite member 1 is not particularly limited, and can be set to a plate shape or a film shape, for example. In addition, the thickness t3 of the composite member 1 is not particularly limited, and can be set to 50 μm or more, for example. The composite member 1 of the present embodiment is formed by a pressurization and heating method as described below. Thus, a composite member 1 having a large thickness can be easily obtained. Note that the thickness t3 of the composite member 1 can be set to 1 mm or more, or can be set to 1 cm or more. The upper limit of the thickness t3 of the composite member 1 is not particularly limited, and can be set to 50 cm, for example.

[0075] Thus, the composite member 1 of the present embodiment includes the inorganic layer 10 containing an inorganic substance containing at least one of a metal oxide and a metal hydroxide oxide. The composite member 1 includes the resin layer 20 provided on the surface of the inorganic layer 10, containing the resin 21 and the inorganic particles 22 dispersed in the resin 21 and directly bonded to the inorganic substance of the inorganic layer 10. The porosity in the cross section of the inorganic layer 10 is 20% or less, and in the case where it is measured by infrared spectroscopy or X-ray diffraction, a peak derived from a hydroxyl group is detected from the inorganic layer 10.

[0076] In the composite member 1 of the present embodiment, the inorganic particles 22 of the resin layer 20 are directly fixed to the inorganic substance of the inorganic layer 10. Thus, the composite member 1 firmly joins the inorganic layer 10 and the resin layer 20 without the use of an adhesive. In addition, the porosity in the cross section of the inorganic layer 10 is 20% or less, and the generation of cracks in the inorganic layer 10 starting from pores can be suppressed, and thus the bending strength of the composite member 1 can be improved. Furthermore, the inorganic layer 10 can be obtained by heating and pressing at a low temperature as described below, and thus, for example, a member having low heat resistance can be added to the inorganic layer 10.

[0077] [Method for manufacturing composite member]

[0078] Next, a method for manufacturing the composite member 1 of the present embodiment will be described.

[0079] First, a method for manufacturing the composite member 1 in which the inorganic substance contained in the inorganic layer 10 is boehmite will be described. The composite member 1 in which the inorganic substance is boehmite can be manufactured by mixing a hydraulic aluminum oxide with a solvent containing water, and then pressing and heating. The hydraulic aluminum oxide is an oxide obtained by heat-treating aluminum hydroxide, and contains p-alumina. Such a hydraulic aluminum oxide has a property of being combined and solidified by a hydration reaction. Thus, by using a pressurized heating method, the hydration reaction of the hydraulic aluminum oxide progresses, and the hydraulic aluminum oxides are combined with each other, and the crystal structure changes in boehmite, and thus the inorganic layer 10 can be formed.

[0080] Specifically, first, a mixture is prepared by mixing a powder of the hydraulic aluminum oxide with a solvent containing water. The solvent containing water is preferably pure water or deionized water. The solvent containing water can contain an acidic substance or a basic substance in addition to water. In addition, the solvent containing water can contain an organic solvent (for example, alcohol or the like) as long as water is the main component.

[0081] The amount of the solvent added with respect to the hydraulic aluminum oxide is preferably an amount in which the hydration reaction of the hydraulic aluminum oxide sufficiently progresses. The amount of the solvent added with respect to the hydraulic aluminum oxide is preferably 20 to 200 mass%, and more preferably 50 to 150 mass%.

[0082] Next, a resin layer containing a resin and inorganic particles is arranged inside the mold. Then, a mixture of the hydraulic aluminum oxide and a solvent containing water is arranged on the surface of the resin layer. The mixture is filled in the inside of the mold. The mixture filled in the mold can be heated as needed. Then, the inside of the mold is brought to a high pressure state by applying pressure to the resin layer and the mixture arranged in the inside of the mold. At this time, the hydraulic aluminum oxide is highly filled, and the particles of the hydraulic aluminum oxide are combined with each other to be highly dense. Specifically, by adding water to the hydraulic aluminum oxide, the hydraulic aluminum oxide is subjected to a hydration reaction, and boehmite and aluminum hydroxide are generated on the surface of the particles of the hydraulic aluminum oxide. Further, by heating and pressurizing the mixture in the inside of the mold, the generated boehmite and aluminum hydroxide diffuse between the adjacent particles of the hydraulic aluminum oxide, and the particles of the hydraulic aluminum oxide are slowly combined with each other. Then, by dehydration reaction using heating, the crystal structure is changed from aluminum hydroxide to boehmite. Note that it is presumed that the hydration reaction of the hydraulic aluminum oxide, the mutual diffusion between the particles of the hydraulic aluminum oxide, and the dehydration reaction are performed at substantially the same time. Further, by heating and pressurizing the mixture and the resin layer, the inorganic substance derived from the mixture and the inorganic particles of the resin layer are directly bonded. For example, the particles of the hydraulic aluminum oxide and the inorganic particles of the resin layer are directly bonded.

[0083] Then, by taking out the shaped body from the inside of the mold, a composite member 1 having the inorganic layer 10 and the resin layer 20 can be obtained.

[0084] Note that the heating and pressurizing conditions of the mixture of the hydraulic aluminum oxide and the solvent containing water are not particularly limited as long as the reaction of the hydraulic aluminum oxide and the solvent progresses. For example, the mixture of the hydraulic aluminum oxide and the solvent containing water is preferably heated to 50 to 300°C, and is pressurized at a pressure of 10 to 600 MPa. Note that the temperature at which the mixture of the hydraulic aluminum oxide and the solvent containing water is heated is more preferably 80 to 250°C, and is further preferably 100 to 200°C. In the case where the resin contained in the resin layer is a thermoplastic resin, heating is preferably performed at a temperature lower than the melting point of the thermoplastic resin. Further, the pressure at which the mixture of the hydraulic aluminum oxide and the solvent containing water is pressurized is more preferably 50 to 600 MPa, and is further preferably 200 to 600 MPa.

[0085] Next, another manufacturing method of the composite member 1 in which the inorganic substance contained in the inorganic layer 10 is boehmite will be described. The composite member 1 in which the inorganic substance is boehmite can be manufactured by mixing aluminum nitride powder and a solvent containing water, and then pressurizing and heating.

[0086] Specifically, first, a powder of aluminum nitride is mixed with a solvent containing water to prepare a mixture. The solvent containing water is preferably pure water or deionized water. The solvent containing water can contain an acidic substance or a basic substance in addition to water. Further, the solvent containing water can contain an organic solvent (e.g., alcohol, etc.) as long as water is the main component. Furthermore, the solvent containing water can contain ammonia.

[0087] The amount of the solvent added with respect to the aluminum nitride is preferably the amount in which the hydrolysis reaction of the aluminum nitride described later progresses and aluminum hydroxide is generated on the surface of the aluminum nitride. The amount of the solvent added with respect to the aluminum nitride is preferably 5 to 100% by mass, and more preferably 20 to 80% by mass.

[0088] Next, a resin layer containing a resin and inorganic particles is arranged inside the mold. Then, the mixture of the aluminum nitride and the solvent containing water is arranged on the surface of the resin layer, and the mixture is filled in the inside of the mold. After the mixture is filled in the mold, the mold is heated as necessary. Then, the inside of the mold becomes a high-pressure state by applying pressure to the resin layer and the mixture arranged in the inside of the mold. At this time, the aluminum nitride is highly filled, and the particles of the aluminum nitride are combined with each other, and thus the aluminum nitride is highly densified. Specifically, by heating and pressurizing the mixture, the aluminum nitride is hydrolyzed and aluminum hydroxide is generated on the surface of the aluminum nitride. The generated aluminum hydroxide diffuses among the adjacent aluminum nitrides, and the aluminum nitrides are slowly linked to each other. Thereafter, by dehydration reaction using heating, the crystal structure of the aluminum hydroxide changes to boehmite. As a result, the adjacent particles of the aluminum nitride are combined via a boehmite phase containing boehmite. Further, by heating and pressurizing the mixture and the resin layer, the inorganic substance derived from the mixture and the inorganic particles of the resin layer are directly cemented.

[0089] Then, by taking out the molded body from the inside of the mold, a composite member 1 having the inorganic layer 10 and the resin layer 20 can be obtained.

[0090] Note that the heating and pressurizing conditions of the mixture of the aluminum nitride and the solvent containing water are not particularly limited as long as the reaction of the aluminum nitride and the solvent and the dehydration reaction of the aluminum hydroxide progress. For example, it is preferable to heat the mixture to 50 to 300°C and pressurize at a pressure of 10 to 600 MPa. In the case where the resin contained in the resin layer is a thermoplastic resin, it is preferable to heat at a temperature lower than the melting point of the thermoplastic resin. Note that the temperature at which the mixture is heated is more preferably 80 to 250°C, and further preferably 100 to 200°C. Further, the pressure at which the mixture is pressurized is more preferably 50 to 600 MPa, and further preferably 200 to 600 MPa.

[0091] Next, a method of manufacturing the composite member 1 in which the inorganic substance contained in the inorganic layer 10 is a metal oxide will be described. A solvent is added to the powder of the inorganic substance. There is no particular limitation on the solvent, and for example, a solvent that can dissolve a part of the inorganic substance when the powder of the inorganic substance is subjected to pressurization and heating can be used. Further, as the solvent, a solvent that can react with the inorganic substance to generate an inorganic substance different from the inorganic substance can be used. As such a solvent, at least one selected from the group consisting of an acidic aqueous solution, an alkaline aqueous solution, water, an alcohol, a ketone, and an ester can be used. As the acidic aqueous solution, an aqueous solution having a pH of 1 to 3 can be used. As the alkaline aqueous solution, an aqueous solution having a pH of 10 to 14 can be used. As the acidic aqueous solution, an aqueous solution of an organic acid is preferably used. Further, as the alcohol, an alcohol having a carbon number of 1 to 12 is preferably used.

[0092] Next, a resin layer containing a resin and inorganic particles is arranged inside the mold. Then, the mixture containing the inorganic substance and the solvent is filled in the inside of the mold in a manner that the mixture is arranged on the surface of the resin layer. After the mixture is filled in the mold, the mold can be heated as needed. Then, by applying pressure to the resin layer and the mixture arranged in the inside of the mold, the inside of the mold becomes a high-pressure state. At this time, the inorganic substance in the mixture is densified, and at the same time, the particles of the inorganic substance are bonded to each other. Further, by heating and pressurizing the mixture and the resin layer, the inorganic substance derived from the mixture is directly bonded to the inorganic particles of the resin layer.

[0093] Here, in the case where the solvent that dissolves a part of the inorganic substance is used as the solvent, in the high-pressure state, the inorganic compound contained in the inorganic substance is dissolved in the solvent. The dissolved inorganic compound is immersed in the gap between the inorganic substances. Then, by removing the solvent in the mixture in this state, the bonding portion 12 derived from the inorganic substance is formed between the inorganic substances. Further, in the case where the solvent that reacts with the inorganic substance to generate an inorganic substance different from the inorganic substance is used as the solvent, in the high-pressure state, the inorganic compound constituting the inorganic substance reacts with the solvent. Then, the other inorganic substance generated by the reaction is filled in the gap between the inorganic substances, and the bonding portion 12 derived from the other inorganic substance is formed.

[0094] As for the heating and pressurizing conditions of the mixture containing the inorganic substance and the solvent, in the case where a solvent that dissolves a part of the inorganic substance is used as the solvent, there is no particular limitation as long as it is a condition in which the dissolution of the surface of the inorganic substance progresses. Further, as for the heating and pressurizing conditions of the mixture, in the case where a solvent that reacts with the inorganic substance to generate an inorganic substance different from the inorganic substance is used as the solvent, there is no particular limitation as long as it is a condition in which the reaction of the inorganic substance with the solvent progresses. For example, it is preferable to heat the mixture containing the inorganic substance and the solvent to 50 to 300°C and then pressurize at a pressure of 10 to 600 MPa. Note that the temperature at the time of heating the mixture containing the inorganic substance and the solvent is more preferably 80 to 250°C, and further preferably 100 to 200°C. In the case where the resin contained in the resin layer is a thermoplastic resin, it is preferable to heat at a temperature lower than the melting point of the thermoplastic resin. Further, the pressure at the time of pressurizing the mixture containing the inorganic substance and the solvent is more preferably 50 to 400 MPa, and further preferably 50 to 200 MPa.

[0095] Then, by taking out the shaped body from the inside of the mold, a composite member 1 provided with the inorganic layer 10 and the resin layer 20 can be obtained.

[0096] Here, as a method of manufacturing an inorganic member containing a ceramic, a sintering method is known. The sintering method is a method of obtaining a sintered body by heating a collection of solid powders containing an inorganic substance at a temperature lower than the melting point. However, in the sintering method, for example, the solid powders are heated to 1000°C or higher. Therefore, even if the sintering method is intended to be used to obtain the inorganic layer 10 containing an organic substance having low heat resistance, the organic substance is carbonized due to heating at a high temperature. However, in the manufacturing method of the composite member 1 of the present embodiment, since heating is performed at a low temperature of 300°C or lower, carbonization of the organic substance is less likely to occur.

[0097] Further, in the manufacturing method of the present embodiment, since the powders of the inorganic substance are heated while being pressurized, the inorganic substance is condensed to become the dense inorganic layer 10. As a result, the number of pores in the inorganic layer 10 is reduced, and thus a composite member 1 having high strength can be obtained.

[0098] Thus, the manufacturing method of the composite member 1 of the present embodiment has a step of mixing the hydraulic aluminum oxide with a solvent containing water to obtain a mixture, and a step of pressurizing and heating the resin layer with the mixture in a state where the mixture is arranged on the surface of the resin layer. Further, the heating and pressurizing conditions of the mixture are preferably set to a temperature of 50 to 300°C and a pressure of 10 to 600 MPa. In the manufacturing method, since the composite member 1 is formed under low temperature conditions, the obtained inorganic layer 10 has boehmite phase as the main body. Thus, the composite member 1 having light weight and excellent chemical stability can be obtained by a simple method.

[0099] Further, the manufacturing method of the composite member 1 of the present embodiment has a step of mixing the aluminum nitride particles with a solvent containing water to obtain a mixture, and a step of pressurizing and heating the resin layer with the mixture in a state where the mixture is arranged on the surface of the resin layer. Further, the heating and pressurizing conditions of the mixture are preferably set to a temperature of 50 to 300°C and a pressure of 10 to 600 MPa. In the manufacturing method of the present embodiment, since the heating temperature is low, the aluminum nitride is combined via boehmite phase in the obtained inorganic layer 10. Thus, the composite member 1 having excellent mechanical strength and chemical stability can be obtained by a simple method.

[0100] Further, the manufacturing method of the composite member 1 of the present embodiment has a step of mixing the aluminum nitride particles with a solvent containing water to obtain a mixture, and a step of pressurizing and heating the resin layer with the mixture in a state where the mixture is arranged on the surface of the resin layer. Further, the heating and pressurizing conditions of the mixture are preferably set to a temperature of 50 to 300°C and a pressure of 10 to 600 MPa. In the manufacturing method of the present embodiment, since the heating temperature is low, the aluminum nitride is combined via boehmite phase in the obtained inorganic layer 10. Thus, the composite member 1 having excellent mechanical strength and chemical stability can be obtained by a simple method.

[0101] [Member provided with composite member]

[0102] Next, a member provided with the composite member 1 will be described. The composite member 1 can be made into a plate shape having a large thickness as described above, and further has excellent stability due to the densification. Further, the composite member 1 has high mechanical strength, and can be cut like a general ceramic member, and can also be surface-processed. Thus, the composite member 1 can be suitably used as a building member. As the building member, there is no particular limitation, and for example, exterior wall materials (wall panels), roof materials, and the like can be exemplified. Further, as the building member, road materials, and exterior tank materials can also be exemplified.

[0103] The composite member 1 can also be suitably used as a member for electronic equipment. As a member for electronic equipment, for example, structural materials, heat-resistant members, insulating members, heat-dissipating members, heat-insulating members, sealing materials, circuit substrates, optical members, and the like can be listed.

[0104] Example

[0105] Hereinafter, the present embodiment will be further described in detail by way of examples, but the present embodiment is not limited to these examples.

[0106] (Example 1)

[0107] First, as an inorganic substance, a hydraulic aluminum oxide BK-112 manufactured by Sumitomo Chemical Co., Ltd. was prepared. The central particle diameter of the hydraulic aluminum oxide was 16 μm. The hydraulic aluminum oxide was a mixture of boehmite and gibbsite (aluminum hydroxide). Note that, in the hydraulic aluminum oxide, ρ-aluminum oxide was also contained. Then, after deionized water was weighed so as to become 80 mass% with respect to the hydraulic aluminum oxide, the hydraulic aluminum oxide and the deionized water were mixed using a mortar and a pestle made of agate, thereby obtaining a mixture.

[0108] Further, a resin plate having a thickness of 2 mm containing a resin and inorganic particles was prepared. The inorganic particles were kneaded into the resin so as to become 33 parts by mass with respect to the resin plate. As the resin, a thermoplastic acrylic resin was used, and as the inorganic particles, the hydraulic aluminum oxide BK-112 manufactured by Sumitomo Chemical Co., Ltd. was used. The thermoplastic acrylic resin was heat-cured by mixing MMA 75 mass% manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC. and PMMA 25 mass% manufactured by Asahi Denka Kogyo Co., Ltd., and adding 0.3 mass% of Torigonox 121-50E manufactured by KAYAKU AKZO Co., Ltd. as a polymerization initiator. The heat-curing conditions were heating in the order of 70°C for 1.5 hours, 80°C for 0.5 hours, and 120°C for 1 hour.

[0109] Next, the resin plate was arranged inside a cylindrical molding mold (Φ 10) having an internal space. Then, the mixture obtained by the above operation was filled in the inside of the mold so as to be arranged on the surface of the resin plate. Then, the resin plate and the mixture arranged in the inside of the mold were heated and pressurized at 400 MPa, 80°C, and 10 minutes, thereby obtaining a composite member having an inorganic layer and a resin layer as a test sample.

[0110] (Example 2)

[0111] The same operation as in Example 1 was performed except that the inorganic particles used in the resin plate were changed to silica particles (fused silica F207C manufactured by Fumitec Corporation) to obtain a composite member as a test sample.

[0112] (Comparative Example 1)

[0113] The same operation as in Example 1 was performed except that no inorganic particles were kneaded in the resin plate to obtain a composite member as a test sample.

[0114] [Evaluation]

[0115] (Scotch Tape Test)

[0116] The resin layer of the cylindrical test sample was fixed, and the adhesive tape (No. 29 manufactured by Nitto Electric Industrial Co., Ltd.) was attached to the surface of the inorganic layer to prevent air bubbles from entering, and the adhesive tape was peeled off from the inorganic layer in good posture, and the adhesion of the inorganic layer to the resin layer was evaluated. The results of the Scotch tape test are shown in Table 1.

[0117] Table 1

[0118] Scotch tape test Example 1 No peel Example 2 No peel Comparative Example 1 With peel

[0119] As shown in Table 1, the results of the Scotch tape test were that the inorganic layer and the resin layer were not peeled off in the test samples of Example 1 and Example 2, and peeling occurred in the test sample of Comparative Example 1. From this result, it was found that the adhesion of the inorganic layer to the resin layer was improved by adding inorganic particles to the resin layer.

[0120] (Cross-Section Observation)

[0121] The cross-section obtained by cutting the cylindrical test sample was observed using a scanning electron microscope (SEM). Sputtering of gold was performed on the observation surface. Figure 5 is an SEM image obtained by observing the test sample of Example 1 at 500 times. Figure 6 is an SEM image obtained by observing the test sample of Example 1 at 5000 times. Figure 7 is an SEM image obtained by observing the test sample of Example 2 at 500 times. Figure 8 is an SEM image obtained by observing the test sample of Example 2 at 5000 times. Figure 9 is an SEM image obtained by observing the test sample of Comparative Example 1 at 500 times. Figure 10 is an SEM image obtained by observing the test sample of Comparative Example 1 at 5000 times.

[0122] In the SEM image of Example 1, as shown in Figure 6As shown within the frame, the inorganic particles 22 contained in the resin layer 20 are continuously and integrally bonded to the particles 11 contained in the inorganic layer 10. In the SEM image of Example 2, as... Figure 8 As shown within the frame, the inorganic particles 22 contained in the resin layer 20 are not continuously and integrally bonded with the particles 11 contained in the inorganic layer 10, but are directly adhered. In the SEM image of Comparative Example 1, as... Figure 10 As shown in the box, voids are observed between the resin layer 20 and the inorganic layer 10.

[0123] Based on the results of Scotch tape tests and cross-sectional observations, it can be concluded that when inorganic particles 22 are included in the resin layer 20, the adhesion between the resin layer 20 and the inorganic layer 10 is improved because the inorganic particles 22 are directly bonded to the inorganic substances contained in the inorganic layer 10.

[0124] (Porosity Measurement)

[0125] First, the cross-section of the cylindrical test sample of Example 1 was subjected to argon-ion cross-section polishing (CP processing). Next, backscattered electron images of the cross-section of the test sample of Example 1 were observed at 2000x magnification using a scanning electron microscope (SEM). The backscattered electron images obtained by observing three locations (positions 1-3) of the cross-section of the test sample of Example 1 are shown below. Figure 11 , Figure 13 and Figure 15 middle.

[0126] Next, the stomata were identified by binarizing the SEM images from the three fields of view. Figure 11 , Figure 13 and Figure 15 The images obtained by binarizing the backscattered electron image are shown below. Figure 12 , Figure 14 and Figure 16 In. Figure 12 , Figure 14 and Figure 16 In the image, the black areas represent pores. Then, the area ratio of the pores is calculated from the binarized image, and the average value is set as the porosity. Based on... Figure 12 The area ratio of the pore portion at position 1 is 0.69%. According to... Figure 14 The area ratio of the pore portion at position 2 is 0.75%. According to... Figure 16 The area ratio of the pore portion at position 3 is 1.14%. Therefore, the porosity of the test sample in Example 1 is the average of the area ratios of the pore portions at positions 1 to 3, which is 0.86%.

[0127] From the results of the porosity measurement, it was found that the inorganic layer of Example 1 had a small porosity. It can be considered that since the inorganic layer has a small porosity, generation of cracks in the inorganic layer starting from the pores can be suppressed. Note that the porosity of the inorganic layer of Example 1 was evaluated, but the inorganic layer of Example 2 was also produced by the same material and method, and thus the same result can be expected.

[0128] (FT-IR (Fourier Transform Infrared Spectroscopy))

[0129] The infrared absorption spectrum of the inorganic layer of Example 1 was measured using an IR Tracer-100 manufactured by Shimadzu Corporation. Note that, as a negative control, the powder of high-purity alumina AA-3 manufactured by Sumitomo Chemical Co., Ltd. was also measured by the same method. Further, as a positive control, aluminum hydroxide KH-108 manufactured by KC Corporation was also measured by the same method. The infrared absorption spectrum was measured by setting the measurement mode to transmission, setting the measurement region to 400 to 7500 cm"1 (1.33 to 25 μm), and setting the number of accumulations to 30. 1 (1.33 to 25 μm), and setting the number of accumulations to 30. Figure 17 are the infrared absorption spectra of the inorganic layer of Example 1, alumina, and aluminum hydroxide.

[0130] Next, the peak area of the peak derived from the hydroxyl group was calculated from the obtained infrared absorption spectrum. Specifically, the peak area was calculated according to the following mathematical expression (1).

[0131] [Mathematical Expression 1]

[0132]

[0133] In the above mathematical expression (1), S1 represents the peak area (cm -1 ), v1 represents the wave number 2600 cm -1 , and v2 represents the wave number 3800 cm -1 . A(v) represents the absorbance at the wave number v, BG(v) represents the absorbance of the BG (background) line at the wave number v, and Δv represents the resolution of the wave number (cm -1 ). Note that the v wavy sign in the above mathematical expression (1) is written as v in the article. Further, the BG line is set to a straight line connecting the infrared absorption spectra of the background regions in both ends of the peak to each other. The background region is set to the wave number region from 2400 cm -1 and lower than 2600 cm -1 , and the wave number region exceeding 3800 cm -1 and 4000 cm -1 or more. Table 2 is the peak area of each infrared absorption spectrum.

[0134] Table 2

[0135]

[0136] According to Figure 17 The peak area of the inorganic layer of Example 1 was 3.76 cm -1 A peak derived from a hydroxyl group was detected from the inorganic layer of Example 1. Note that the peak area of the inorganic layer of Example 1 was calculated only, and the inorganic layer of Example 2 was also produced by the same material and method, and thus the same result was expected.

[0137] (X-ray Diffraction Measurement)

[0138] A MiniFlex powder X-ray diffraction (XRD) apparatus manufactured by Rigaku Corporation was used to measure the XRD pattern of a powder obtained by pulverizing the inorganic layer of Example 1 with an alumina mortar. The X-ray source was set to Cu Kα (wavelength ), the tube voltage was set to 40 kV, the tube current was set to 15 mA, and the measurement range was set to 2θ = 10° to 70°. Note that, as a negative control, the XRD pattern of a powder of high-purity alumina AA-3 manufactured by Sumitomo Chemical Co., Ltd. was also measured by the same method. Figure 18 is a graph showing the XRD pattern of the inorganic layer of Example 1 and the XRD pattern of alumina. Furthermore, Figure 19 is a graph obtained by enlarging the XRD pattern of Figure 18 .

[0139] Next, from the obtained XRD pattern, the peak area of a peak centered on the main peak (2θ = 14.4°) of boehmite (AlOOH) was calculated. Specifically, the peak area was calculated in accordance with the following mathematical expression (2).

[0140] [Mathematical Expression 2]

[0141]

[0142] In the above mathematical expression (2), S2 represents the peak area (cm -1 ), 2θ1 represents the angle 2θ = 12°, and 2θ2 represents the angle 2θ = 16.8°. I(2θ) represents the intensity (cps) at the angle 2θ, BG(2θ) represents the intensity (cps) of the BG (background) line at the angle 2θ, and Δ(2θ) represents the step angle (2θ = 0.02°). Furthermore, the BG line was set to a straight line connecting the XRD patterns of the background regions in both ends of the peak to each other. The background regions were set to the angle regions of 11.5° or more and less than 12° and more than 16.8° and 17.3° or less. Table 3 is the peak area of each XRD pattern.

[0143] Table 3

[0144]

[0145] according to Figure 18 and Figure 19 And the results in Table 3 show that, compared with alumina at the background level, the peak area of ​​the inorganic layer in Example 1 is 8640°(2θ)·cps, and peaks originating from hydroxyl groups were detected in the inorganic layer of Example 1.

[0146] Next, the obtained XRD pattern is analyzed using Rietveld to determine the proportions of each phase. Figure 20 From top to bottom, the charts show the fitting results of the XRD patterns of Example 1, and the XRD patterns of boehmite, γ-alumina, and α-alumina registered in ICSD (Inorganic Crystal Structure Database). Figure 21 From top to bottom, the tables show the fitting results of the XRD pattern of alumina, and the XRD patterns of α-alumina and boehmite registered in ICSD. Table 4 shows the proportions of each phase obtained from Rietveld analysis.

[0147] Table 4

[0148] Example 1 Alumina Boehmite 56 1.7 Alpha-alumina 14 98.3 Gamma-alumina 29 -

[0149] The results of Rietveld's analysis showed that, compared to alumina where the boehmite phase was present at a background level, the inorganic layer of Example 1 contained 56% by mass of boehmite phase, and peaks originating from hydroxyl groups were detected in the inorganic layer of Example 1. It should be noted that only the inorganic layer of Example 1 was analyzed, but the inorganic layer of Example 2 was also prepared using the same materials and methods, so the same results are expected.

[0150] (TG (Thermogravimetric Analysis))

[0151] Figure 22 These are the TG curves for boehmite and aluminum hydroxide. (Example:) Figure 22 As shown, when boehmite or aluminum hydroxide is heated, a weight reduction can be observed due to the desorption of hydroxyl groups and the formation of alumina via dehydration condensation. Based on this result, alumina is formed when inorganic substances containing hydroxyl groups, such as boehmite or aluminum hydroxide, are heated to, for example, above 1000°C using a sintering method. Therefore, it can be considered that hydroxyl groups, as in this embodiment, are not detected in such sintered bodies.

[0152] The full contents of Japanese Special Appeal No. 2020-125102 (application date: July 22, 2020) are hereby cited.

[0153] The above describes the present embodiment, but the present embodiment is not limited to these, and various modifications can be made within the scope of the gist of the present embodiment.

[0154] Industrial applicability

[0155] According to the present disclosure, it is possible to provide a composite member in which an inorganic layer and a resin layer are firmly joined without an adhesive.

[0156] Symbol explanation:

[0157] 1 Composite member

[0158] 10 Inorganic layer

[0159] 20 Resin layer

[0160] 21 Resin

[0161] 22 Inorganic particles

Claims

1. A composite member comprising: an inorganic layer containing an inorganic substance containing at least one of a metal oxide and a metal oxyhydroxide; and a resin layer provided on a surface of the inorganic layer, containing a resin and an inorganic particle dispersed in the resin and directly bonded to the inorganic substance of the inorganic layer; a porosity in a cross section of the inorganic layer is 20% or less, a peak derived from a hydroxyl group is detected from the inorganic layer when measured by infrared spectroscopy or X-ray diffraction, the inorganic layer contains a plurality of particles and a bonding portion that bonds each of the plurality of particles, the inorganic substance is contained in both the plurality of particles and the bonding portion, a thickness of the inorganic layer is 50 μm or more, the porosity in the cross section of the inorganic layer is 10% or less, the inorganic particle has a hydroxyl group, the inorganic particle is continuously and integrally bonded to the inorganic substance contained in the inorganic layer, the inorganic particle contains a metal element contained in the inorganic substance of the inorganic layer, a content ratio of the inorganic particle with respect to the resin layer is 10% by volume to 70% by volume, and the inorganic substance contained in the inorganic layer is a polycrystal. ​ ​ ​ ​ ​ ​ ​ 2. The composite member of claim 1, wherein, ​ 3. The composite member according to claim 1 or 2, wherein ​ 4. The composite member of claim 1 or 2, wherein, ​ 5. The composite member of claim 1 or 2, wherein, ​ 6. The composite member of claim 1 or 2, wherein, ​ 7. The composite member of claim 1 or 2, wherein, ​

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