Method for improving airtightness of composite molded product, composite molded product, and method for manufacturing the same

Abstract

To provide a method for improving airtightness of a composite molded product obtained by insert molding using a thermoplastic resin composition, a composite molded product having excellent airtightness, and a method for manufacturing the same.SOLUTION: There is provided a method for improving airtightness of a composite molded product in which at least a part of a metal member is embedded in a thermoplastic resin composition. The method includes infiltrating an impregnating agent into an interface between the metal member and the thermoplastic resin composition of the composite molded product, and curing the impregnating agent, wherein the impregnating agent contains 0 to 10 pts.mass of a shrinkage inhibitor (A), 0 to 10 pts.mass of an adhesion imparting agent (B), and a total amount of the shrinkage inhibitor (A) and the adhesion imparting agent (B) of more than 0 pt.mass to 20 pts.mass or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for improving the airtightness of a composite molded article, a composite molded article, and a method for manufacturing the same. [Background technology]

[0002] Taking advantage of their processability, thermoplastic resin compositions are used in a variety of applications, such as automobile parts, electrical and electronic parts, etc. Among these, particularly for parts used in combination with metal members, composite molded products in which metal members are inserted into a thermoplastic resin and molded are sometimes used in order to simplify the manufacturing process and reduce the number of parts. In composite molded products containing such metal components, such as connector parts, airtightness and waterproofness are required at the interface between the resin and the metal component. Therefore, methods for improving the adhesion at the interface in insert-molded products have been studied. For example, known methods include a method of insert-molding a metal component on which a B-staged or pre-gelled epoxy resin adhesive layer (sealing layer) is formed (Patent Document 1), a method of joining a rubber-like elastic body to a metal terminal having a finely textured surface and then insert-molding (Patent Document 2), and a method of injecting a one-component heat-curing impregnation liquid into the gap between the resin molded body and the connection terminal of the insert-molded product and curing it (Patent Document 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-245665 [Patent Document 2] Japanese Patent Application Publication No. 2018-129197 [Patent Document 3] Japanese Patent Application Publication No. 8-241902 Summary of the Invention [Problem to be solved by the invention]

[0004] In the methods described in Patent Documents 1 and 2, insert molding is performed after a sealing layer of adhesive or elastomer is formed on the surface of the metal member, so the sealing layer may be washed away or deformed by the resin pressure during insert molding, and sufficient airtightness may not be obtained. Furthermore, in the method described in Patent Document 3, it is necessary to select a thermoplastic resin that has high adhesion to the metal member. An object of the present disclosure is to provide a method for improving the airtightness of a composite molded product, a composite molded product with excellent airtightness, and a method for manufacturing the same, without being limited to the use of a thermoplastic resin that has high adhesion to metal components. [Means for solving the problem]

[0005] The present disclosure encompasses the following aspects. [First embodiment] A method for improving the airtightness of a composite molded article in which at least a portion of a metal member is embedded in a thermoplastic resin composition, the method comprising: The method includes infiltrating an impregnating agent into an interface between the metal member and the thermoplastic resin composition of the composite molded product, and curing the impregnating agent, The impregnating agent contains, relative to 100 parts by mass of the impregnating agent, 0 to 10 parts by mass of a shrinkage inhibitor (A) having an average particle size (D50) of 0.01 μm to 5 μm as measured by a laser diffraction scattering method, 0 to 10 parts by mass of an adhesion promoter (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof, and the total amount of the shrinkage inhibitor (A) and the adhesion promoter (B) is more than 0 to 20 parts by mass. [Second embodiment] A composite molded article in which at least a part of a metal member is embedded in a thermoplastic resin composition, At the interface between the metal member and the thermoplastic resin composition, A shrinkage inhibitor (A) having an average particle size (D50) measured by a laser diffraction scattering method of 0.01 μm or more and 5 μm or less, and / or an adhesion promoter (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof; Composite molded products including: [Third embodiment] A method for producing a composite molded article in which at least a part of a metal member is embedded in a thermoplastic resin composition, comprising: The manufacturing method includes: insert-molding the metal member with the thermoplastic resin composition; After the insert molding, an impregnating agent is infiltrated into the interface between the metal member and the thermoplastic resin composition, and the impregnating agent is cured. a production method in which the impregnating agent contains, relative to 100 parts by mass of the impregnating agent, from 0 to 10 parts by mass of a shrinkage inhibitor (A) having an average particle size (D50) of from 0.01 μm to 5 μm as measured by a laser diffraction scattering method, from 0 to 10 parts by mass of an adhesion imparting agent (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof, and the total of the shrinkage inhibitor (A) and the adhesion imparting agent (B) is more than 0 to 20 parts by mass. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to provide a method for improving the airtightness of a composite molded product, a composite molded product with excellent airtightness, and a method for manufacturing the same, without being limited to the use of a thermoplastic resin that has high adhesion to metal components. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a diagram showing the shape of a test piece used in an airtightness test. [Figure 2] 1 is a photograph of a test piece used in an airtightness test. [Figure 3] FIG. 1 is a diagram showing a schematic configuration of a test device for an airtightness test. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the present disclosure will be described in detail below. However, the scope of the present disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the present disclosure. Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. Furthermore, when multiple upper and lower limit values ​​are described for a specific parameter, any of these upper and lower limit values ​​can be combined to form a suitable numerical range. Furthermore, the lower and / or upper limit values ​​of a numerical range described in this disclosure are numerical values ​​within that numerical range and may be replaced with numerical values ​​shown in the examples. The expression "X to Y" indicating a numerical range means "X or more and Y or less." If a specific description described for one embodiment also applies to other embodiments, that description may be omitted in other embodiments.

[0009] [Method for improving the airtightness of composite molded products] A first embodiment of the present disclosure relates to a method for improving the airtightness of a composite molded article in which at least a part of a metal member is embedded in a thermoplastic resin composition. The method according to the first embodiment comprises: The method includes infiltrating an impregnating agent into an interface between the metal member and the thermoplastic resin composition of the composite molded product, and curing the impregnating agent, The impregnating agent contains, relative to 100 parts by mass of the impregnating agent, 0 to 10 parts by mass of a shrinkage inhibitor (A) having an average particle size (D50) of 0.01 μm to 5 μm as measured by a laser diffraction scattering method, 0 to 10 parts by mass of an adhesion promoter (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof, and the total amount of the shrinkage inhibitor (A) and the adhesion promoter (B) is more than 0 to 20 parts by mass. In general, composite molded products in which metal members are insert-molded with thermoplastic resin compositions are widely used in the manufacture of electronic components such as connectors and switches, which utilize the insulating properties of the resin. However, from the viewpoint of durability and reliability, airtightness is required at the interface between the metal member and the thermoplastic resin composition. The above method can further improve the adhesiveness at the interface between the metal member and the thermoplastic resin composition, thereby further improving the airtightness of the composite molded article. As used herein, "insert molding" refers to a molding method in which a metal or other component is inserted into an injection mold, and a material such as resin is injected to integrate the inserted component with the resin. When the composite molded article according to the first embodiment is a molded article manufactured by insert molding, the insert molding to obtain the composite molded article can be performed by a known method. That is, a metal component is placed in an injection mold, and then a thermoplastic resin composition is injection molded into the mold to obtain a composite molded article in which the metal component is partially embedded in the thermoplastic resin composition (the metal component is partially exposed). In order to improve adhesion between the metal component and the thermoplastic resin composition, the injection molding may be performed using known methods such as preheating the metal component, increasing the mold temperature (e.g., 100°C or higher), or increasing the injection pressure and / or dwell pressure. In this specification, "airtightness" refers to a property that includes not only the ability to block gases such as air and water vapor, but also the ability to block liquids such as water and organic solvents. In this specification, the term "interface" refers to the region where the metal member embedded in the thermoplastic resin composition is in contact with the thermoplastic resin composition, and includes the boundary portion of the region where they are in complete contact with each other, the boundary portion of the region where there is a gap through which the impregnating agent described below can penetrate, and the gap itself.

[0010] <Penetration of impregnating agent> The method according to the first embodiment includes infiltrating an impregnating agent into the interface between the metal member and the thermoplastic resin composition of the composite molded article. In this embodiment, the impregnation agent can be introduced into the composite molded article by immersing the composite molded article in the impregnation agent, injecting the impregnation agent into the interface with the thermoplastic resin composition from the end of the composite molded article where the metal member is exposed, applying the impregnation agent to the interface, spraying the impregnation agent onto the interface, bringing the impregnation agent into contact with the interface and allowing it to be absorbed by capillary action, or a combination of one or more of these methods. Furthermore, to increase the efficiency of the impregnation agent's introduction into the interface, the composite molded article may be placed under reduced pressure in a vacuum and then contacted with the impregnation agent by immersion, injection, application, spraying, or the like, or pressure may be applied while the impregnation agent is in contact with the interface. In one embodiment, from the viewpoint of allowing the impregnating agent to sufficiently penetrate into the interface between the metal member and the thermoplastic resin composition, the impregnation of the impregnating agent is preferably performed by vacuum pressure impregnation. Vacuum pressure impregnation can be performed using a commercially available vacuum pressure impregnation device, and the pressure can be appropriately adjusted depending on conditions such as the viscosity of the impregnating agent.

[0011] <Curing of impregnating agent> The method according to the first embodiment includes curing the impregnating agent. The curing of the impregnating agent according to this embodiment can be achieved by curing the impregnating agent through various treatments based on the principles described below in the description of the impregnating agent, such as drying, heating, anaerobic treatment, mixing with a curing agent, and electromagnetic wave irradiation. From the viewpoint of ensuring the penetration of the impregnating agent, this curing treatment is preferably carried out after the impregnating agent has penetrated the interface between the metal member and the thermoplastic resin composition of the composite molded product, i.e., after the impregnating agent has penetrated. On the other hand, from the viewpoint of improving productivity, the curing may be carried out simultaneously with the penetration of the impregnating agent, while balancing the time required for the impregnating agent penetration and the time required for the impregnating agent curing. In one embodiment, the impregnating agent is preferably cured by heating. Heating can be performed using a commercially available thermostatic bath, and conditions such as heating temperature and heating time can be appropriately adjusted depending on the degree of curing of the impregnating agent.

[0012] <Impregnating agent> In this embodiment, the impregnating agent penetrates into the interface between the metal member and the thermoplastic resin composition of the composite molded product and hardens. Therefore, it is preferable that the impregnating agent is initially liquid and hardens under various conditions commonly used for hardening adhesives, such as drying, heating, anaerobic conditions, mixing of a curing agent, and electromagnetic wave irradiation. Among these, it is more preferable to use a heat-hardening impregnating agent in terms of ease of processing and mass productivity. The impregnating agent may also contain various additives.

[0013] The chemical structure of the impregnating agent is not particularly limited, but is preferably any one of epoxy-based, acrylic-based, polyester-based, and silicone-based impregnating agents, or a combination thereof. From the viewpoints of adhesion to the thermoplastic resin composition and heat resistance in reflow treatment, it is more preferable to use one or more impregnating agents selected from epoxy-based, acrylic-based, and polyester-based impregnating agents, and even more preferable to use acrylic-based and / or polyester-based impregnating agents. Acrylic-based impregnating agents can be washed with water after being impregnated into a composite molded product. On the other hand, epoxy-based impregnating agents can be washed with organic solvents such as toluene and xylene, so acrylic-based impregnating agents are particularly preferred from the viewpoint of low environmental impact.

[0014] (Shrinkage inhibitor (A)) In the method according to the first embodiment, the impregnating agent contains 0 to 10 parts by mass of a shrinkage inhibitor (A) having an average particle size (D50) of 0.01 μm to 5 μm, as measured by laser diffraction scattering, per 100 parts by mass of the impregnating agent. The inclusion of the shrinkage inhibitor (A) reduces the surface tension of the impregnating agent, allowing it to more easily penetrate the interface between the metal member and the thermoplastic resin composition, thereby more easily fulfilling its function as a shrinkage inhibitor and reducing the impact of shrinkage of the thermoplastic resin composition. As a result, the airtightness of the composite molded article can be further improved. In one embodiment, the shrinkage inhibitor (A) preferably contains inorganic particles having an average particle diameter (D50) of 0.01 μm or more and 5 μm or less. The inorganic particles are preferably inorganic oxide particles, more preferably silica particles, and particularly preferably spherical silica particles. In the present disclosure, "spherical silica particles" means that when silica particles are observed using a scanning electron microscope, the shape of each particle is observed to be circular or rounded. When the shrinkage inhibitor (A) contains spherical silica particles, the average circularity thereof is preferably 0.9 or more. The average particle size (D50) of the shrinkage inhibitor (A) is 0.01 μm or more and 5 μm or less, preferably 0.015 μm or more and 1 μm or less, more preferably 0.02 μm or more and 0.5 μm or less, and even more preferably 0.02 μm or more and 0.2 μm or less. The amount of the shrinkage inhibitor (A) blended is 0 parts by mass or more and 10 parts by mass or less, preferably 0.1 parts by mass or more and 8 parts by mass or less, and more preferably 0.5 parts by mass or more and 5 parts by mass or less, relative to the total amount (100 parts by mass) of the impregnation agent. The average particle size (D50) of the shrinkage inhibitor (A) refers to a value measured by a laser diffraction scattering method. Specifically, the particle size (D50) at which the cumulative value reaches 50% in the volume-based particle size distribution measured by the laser diffraction scattering method is defined as the average particle size. In one embodiment, the impregnating agent preferably contains a shrinkage inhibitor (A) as an essential component, and may contain 0.1 to 5 parts by mass of the shrinkage inhibitor (A) per 100 parts by mass of the impregnating agent.

[0015] (Adhesion imparting agent (B)) In the method according to the first embodiment, the impregnating agent contains from 0 to 10 parts by mass of an adhesion promoter (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof, relative to 100 parts by mass of the impregnating agent. The inclusion of the adhesion promoter (B) further improves the adhesion at the interface between the metal member and the thermoplastic resin composition, thereby enabling further improvement in the airtightness of the composite molded article. In one embodiment, from the viewpoint of bonding to metal members, the adhesion promoter (B) is preferably a compound having one or more functional groups selected from a hydroxy group, an amino group, an alkoxy group, a triazine ring, and derivatives thereof. The hydroxy group or alkoxy group may be bonded to a metal element. The metal element may be one or more selected from Si, Al, and Ti. The compound used as the adhesion promoter (B) may be one of the above compounds or a combination of two or more of them. The amount of the adhesion promoter (B) is from 0 to 10 parts by mass, preferably from 0.1 to 8 parts by mass, and more preferably from 0.5 to 5 parts by mass, relative to the total amount (100 parts by mass) of the impregnating agent.

[0016] In the method according to the first embodiment, the impregnating agent contains more than 0 and 20 parts by mass or less of the shrinkage inhibitor (A) and the adhesion promoter (B) in total relative to 100 parts by mass of the impregnating agent. In one embodiment, the total amount of the shrinkage inhibitor (A) and the adhesion promoter (B) is preferably more than 0 parts by mass and not more than 10 parts by mass, more preferably more than 0 parts by mass and not more than 5 parts by mass, and more preferably more than 0 parts by mass and not more than 2 parts by mass, per 100 parts by mass of the impregnation agent.

[0017] (silicone compounds) In one embodiment, the impregnating agent preferably further contains a silicone compound. By containing the silicone compound, the silicone compound acts as a stress reducer in the impregnating agent, further improving the adhesion at the interface between the metal member and the thermoplastic resin composition, and further improving the airtightness of the composite molded product. In one embodiment, the silicone compound is preferably a spherical silicone powder, and preferably a silicone powder that is a spherical powder in which the surface of the spherical silicone powder is coated with a silicone resin. In one embodiment, the amount of the silicone compound in the impregnating agent is preferably 0 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and even more preferably 0.5 to 1 part by mass, per 100 parts by mass of the impregnating agent.

[0018] In this embodiment, by adding any one of the shrinkage inhibitor (A), adhesion imparting agent (B), and silicone compound to the impregnating agent, it is possible to reduce the decrease in airtightness of the composite molded product due to heat shock, heat treatment, etc.

[0019] <Metal parts> In the method according to the first embodiment, the metal member is embedded in the thermoplastic resin composition. When the composite molded article is an electronic component such as a connector, the metal member functions as a conductive member for electrical connection. The metal member is preferably surface-treated by one or more methods selected from physical roughening, chemical roughening, and surface activation. By surface-treating the metal member, the adhesion at the interface between the metal member and the thermoplastic resin composition is further improved, and the airtightness of the composite molded article can be further improved.

[0020] Examples of physical roughening include grinding processes such as sandblasting, shot blasting, liquid honing, and filing, as well as unevenness transfer such as embossing, laser light irradiation, and thermal spraying. Examples of chemical roughening include etching with an acid or base and anodizing. These surface treatment methods can also be used in combination. Metal members that have been subjected to these surface treatments preferably have fine irregularities with a surface roughness Ra of 0.1 to 3 μm. The surface roughness of the metal member is more preferably Ra = 0.2 to 1 μm, and even more preferably Ra = 0.2 to 0.6 μm. The surface roughness (Ra) of the metal member can be measured using a contact surface roughness measuring instrument (for example, Mitutoyo Surftest SV3000S) or a non-contact surface roughness measuring instrument (Keyence VK-9500). Examples of surface activation include formation of an oxygen-containing film, formation of a hydroxyl-containing film, formation of a nitrogen-containing film, and electromagnetic wave irradiation, and these may be combined. Here, examples of electromagnetic wave irradiation include ultraviolet light irradiation and vacuum ultraviolet light irradiation, as well as corona discharge treatment and plasma treatment.

[0021] <Thermoplastic resin composition> In the method according to the first embodiment, the thermoplastic resin composition preferably contains 100 parts by mass of a thermoplastic resin, 0 to 100 parts by mass of a fibrous filler, and 5 to 100 parts by mass of one or more non-fibrous fillers selected from plate-like fillers, spherical fillers, powdery fillers, curved fillers, and irregular fillers. The content of the non-fibrous filler is more preferably 10 to 50 parts by mass, and even more preferably 15 to 40 parts by mass.

[0022] The thermoplastic resin is not particularly limited as long as it is a thermoplastic resin that can be used in injection molding, and examples thereof include polyamide, acrylic resin, styrene resin, polyolefin resin, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyarylene sulfide, polyacetal, liquid crystal resin (e.g., aromatic polyester, aromatic polyester amide), polyimide, polyarylate, polyetherimide, polyether ether ketone, etc. These can be used alone or in combination of two or more. Among them, in terms of excellent mechanical properties, heat resistance, and chemical resistance, it is preferable to contain one or more resins selected from polyamide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyarylene sulfide, polyacetal, liquid crystal resin, polyarylate, polyetherimide, and polyether ether ketone. Furthermore, in terms of excellent moldability, it is more preferable to contain one or more resins selected from polyarylene sulfide, polyethylene terephthalate, polybutylene terephthalate, and liquid crystal resin.

[0023] (fibrous filler) Examples of fibrous fillers include glass fibers, aramid fibers, carbon fibers, and whiskers. Chopped strand or roving glass fibers can be used as glass fibers, and glass fibers treated with a sizing agent containing a silane coupling agent such as an aminosilane compound or an epoxysilane compound and / or one or more epoxy compounds such as urethane, vinyl acetate, bisphenol A diglycidyl ether, or a novolac epoxy compound are preferably used. The silane coupling agent and / or the sizing agent may be used in an emulsion form.

[0024] As the glass fibers, from the viewpoint of suppressing warpage due to anisotropy of molding shrinkage rate caused by orientation and thereby making it easier to obtain airtightness of the composite molded product, it is more preferable to use glass fibers with a relatively small aspect ratio, such as short glass fibers such as milled fibers, or glass fibers with a flat cross section such as a cocoon shape, oval shape, or elliptical shape (for example, the ratio of the major axis to the minor axis of the cross section is 1.3 to 10).

[0025] (non-fibrous filler) As the non-fibrous filler, any of plate-shaped fillers, spherical fillers, powder fillers, curved fillers, irregular fillers, and combinations of these can be used. However, in order to reduce warpage, fillers with little anisotropy are preferred, so plate-shaped, spherical, powder-shaped, etc. are preferred, and it is particularly preferable to use fillers with an aspect ratio close to 1.

[0026] Specific examples of the platy filler include platy talc, mica, glass flakes, metal flakes, and combinations thereof. Specific examples of the spherical filler include glass beads, glass balloons, spherical silica, and combinations thereof. Examples of powder fillers include glass powder, talc powder, quartz powder, kaolin, clay, diatomaceous earth, wollastonite, silicon carbide, silicon nitride, metal powder, powder of inorganic acid metal salts (calcium carbonate, zinc borate, calcium borate, zinc stannate, calcium sulfate, barium sulfate, etc.), powder of metal oxides (magnesium oxide, iron oxide, titanium oxide, zinc oxide, alumina, etc.), powder of metal hydroxides (aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, alumina hydrate (boehmite), etc.), powder of metal sulfides (zinc sulfide, molybdenum sulfide, tungsten sulfide, etc.), and combinations thereof. The curved filler may be, for example, crushed glass balloons.

[0027] These non-fibrous fillers may be surface-treated (surface-coated) with an inorganic compound and / or an organic compound. Preferred examples of inorganic compounds used for the surface treatment include inorganic oxides and hydroxides of aluminum, silicon, zirconium, cerium, etc., such as aluminum hydroxide, alumina, silica, zirconia, zirconium hydroxide, zirconia hydrate, cerium oxide, cerium oxide hydrate, and cerium hydroxide. These inorganic compounds may also be hydrates. Among these, aluminum hydroxide and silica are preferred, and when silica is used, silica hydrate represented by SiO₂·nH₂O is particularly preferred. Preferred organic compounds used for the surface treatment include epoxy compounds and amine compounds, with more preferred examples including epoxy compounds such as bisphenol A epoxy and novolac epoxy, and amine compounds such as monoethanolamine, diethanolamine, triethanolamine, and dichlorohexylamine.

[0028] From the viewpoint of corrosion resistance of metals such as metal members and molding dies, the content of free inorganic acid contained in the fibrous filler or non-fibrous filler is preferably 0.5 parts by mass or less per 100 parts by mass of the fibrous filler or non-fibrous filler. The size of the filler can be appropriately selected in consideration of the balance between the effect of improving mechanical properties and the effect of suppressing warpage and the flowability, etc.

[0029] In addition to the above, other known substances may be added to the thermoplastic resin composition according to this embodiment, as long as the effects of the present invention are not impaired. For example, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, colorants such as dyes and pigments, release agents, lubricants, crystallization accelerators, crystal nucleating agents, flame retardants, flame retardant assistants, anti-dripping agents, and the like.

[0030] [Composite molded product] A second embodiment of the present disclosure relates to a composite molded article in which at least a portion of a metal member is embedded in a thermoplastic resin composition. In the composite molded article according to the second embodiment, at the interface between the metal member and the thermoplastic resin composition, A shrinkage inhibitor (A) having an average particle size of 0.01 μm or more and 5 μm or less as measured by a laser diffraction scattering method, and / or an adhesion promoter (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof; A composite molded article comprising:

[0031] In the composite molded article according to the second embodiment, the shrinkage inhibitor (A) and the adhesion promoter (B) may be obtained by impregnating and curing an impregnating agent at the interface between the metal member and the thermoplastic resin composition of the composite molded article by the method according to the first embodiment, but the method is not limited to this.

[0032] In one embodiment, the shrinkage inhibitor (A) preferably contains silica particles, more preferably spherical silica particles, and has an average particle size of 0.01 μm to 5 μm, preferably 0.015 μm to 1 μm, more preferably 0.02 μm to 0.5 μm, and even more preferably 0.02 μm to 0.2 μm. In one embodiment, the content of the shrinkage inhibitor (A) in the cured impregnating agent is from 0 to 10 parts by mass, preferably from 0.1 to 8 parts by mass, and more preferably from 0.5 to 5 parts by mass, per 100 parts by mass of the cured impregnating agent. The average particle size of the shrinkage inhibitor (A) is a value measured by laser diffraction scattering. In one embodiment, the adhesion promoter (B) is preferably a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof. Among these, from the viewpoint of bonding to metal components, a compound having one or more functional groups selected from a hydroxy group, an amino group, an alkoxy group, a triazine ring, and derivatives thereof is more preferred. Furthermore, the hydroxy group or alkoxy group may be bonded to a metal element, and the metal element may be one or more selected from Si, Al, and Ti. The compound used as the adhesion promoter (B) may be one of the above compounds, or a combination of two or more of them. In one embodiment, the content of the adhesion promoter (B) in the cured impregnating agent is from 0 to 10 parts by mass, preferably from 0.1 to 8 parts by mass, and more preferably from 0.5 to 5 parts by mass, relative to 100 parts by mass of the cured impregnating agent.

[0033] In one embodiment, the content of the shrinkage inhibitor (A) and the adhesion promoter (B) in the cured impregnating agent is preferably more than 0 parts by mass and not more than 20 parts by mass, more preferably more than 0 parts by mass and not more than 10 parts by mass, even more preferably more than 0 parts by mass and not more than 5 parts by mass, and particularly preferably more than 0 parts by mass and not more than 2 parts by mass, per 100 parts by mass of the cured impregnating agent.

[0034] [Manufacturing method for composite molded products] A third embodiment of the present disclosure relates to a method for producing a composite molded article in which at least a portion of a metal member is embedded in a thermoplastic resin composition. A manufacturing method according to a third embodiment includes insert-molding the metal member with the thermoplastic resin composition; After the insert molding, an impregnating agent is infiltrated into the interface between the metal member and the thermoplastic resin composition, and the impregnating agent is cured. The impregnating agent contains, relative to 100 parts by mass of the impregnating agent, from 0 to 10 parts by mass of a shrinkage inhibitor (A) having an average particle size (D50) of from 0.01 μm to 5 μm as measured by a laser diffraction scattering method, from 0 to 10 parts by mass of an adhesion promoter (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof, and the total amount of the shrinkage inhibitor (A) and the adhesion promoter (B) is more than 0 to 20 parts by mass.

[0035] In the third embodiment, the "insert molding" can be performed by a known method as described above. Furthermore, after insert molding, the method described in the first embodiment can be preferably used to infiltrate the impregnating agent into the interface between the metal member and the thermoplastic resin composition and to harden the impregnating agent. As the metal member and the thermoplastic resin composition, those explained in the first embodiment can also be preferably used. In one embodiment, it is preferable to subject the surface of the metal member to one or more of physical roughening, chemical roughening, and surface activation before insert molding.

[0036] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure are disclosed below. [1] A method for improving the airtightness of a composite molded article in which at least a part of a metal member is embedded in a thermoplastic resin composition, the method comprising: The method includes infiltrating an impregnating agent into an interface between the metal member and the thermoplastic resin composition of the composite molded product, and curing the impregnating agent, The impregnating agent contains, relative to 100 parts by mass of the impregnating agent, 0 to 10 parts by mass of a shrinkage inhibitor (A) having an average particle size (D50) of 0.01 μm to 5 μm as measured by a laser diffraction scattering method, 0 to 10 parts by mass of an adhesion promoter (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof, and the total amount of the shrinkage inhibitor (A) and the adhesion promoter (B) is more than 0 to 20 parts by mass, relative to 100 parts by mass of the impregnating agent. [2] The method according to [2], wherein the shrinkage inhibitor (A) comprises spherical silica particles. [3] The method according to [1] or [2], wherein the adhesion promoter (B) comprises a triazine compound containing a trialkoxysilyl group. [4] The method according to any one of [1] to [3], wherein the impregnating agent is an acrylic impregnating agent and / or a polyester impregnating agent. [5] The method according to any one of [1] to [4], wherein the impregnating agent further contains a silicone compound. [6] The method according to any one of [1] to [5], wherein the metal member is surface-treated by one or more methods selected from physical roughening, chemical roughening, and surface activation. [7] The method according to [6], wherein the surface activation is one or more selected from the group consisting of formation of an oxygen-containing film, formation of a hydroxyl-containing film, formation of a nitrogen-containing film, and electromagnetic wave irradiation. [8] The method according to any one of [1] to [7], wherein the thermoplastic resin composition contains, per 100 parts by mass of thermoplastic resin, 0 parts by mass or more and 100 parts by mass or less of a fibrous filler, and 10 parts by mass or more and 100 parts by mass or less of one or more non-fibrous fillers selected from a plate-like filler, a spherical filler, a powdery filler, a curved filler, and an irregular filler. [9] The method according to any one of [1] to [8], wherein the impregnation with the impregnating agent is carried out by vacuum pressure impregnation.

[10] The method according to any one of [1] to [9], wherein the curing of the impregnating agent is carried out by heating.

[11] A composite molded product in which at least a part of a metal member is embedded in a thermoplastic resin composition, At the interface between the metal member and the thermoplastic resin composition, A shrinkage inhibitor (A) having an average particle size (D50) measured by a laser diffraction scattering method of 0.01 μm or more and 5 μm or less, and / or an adhesion promoter (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof; Composite molded products including:

[12] The composite molded article according to

[11] , wherein the shrinkage inhibitor (A) contains spherical silica particles.

[13] A method for producing a composite molded product in which at least a part of a metal member is embedded in a thermoplastic resin composition, comprising: The manufacturing method includes: insert-molding the metal member with the thermoplastic resin composition; After the insert molding, an impregnating agent is infiltrated into the interface between the metal member and the thermoplastic resin composition, and the impregnating agent is cured. a production method in which the impregnating agent contains, relative to 100 parts by mass of the impregnating agent, from 0 to 10 parts by mass of a shrinkage inhibitor (A) having an average particle size (D50) of from 0.01 μm to 5 μm as measured by a laser diffraction scattering method, from 0 to 10 parts by mass of an adhesion imparting agent (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof, and the total of the shrinkage inhibitor (A) and the adhesion imparting agent (B) is more than 0 to 20 parts by mass. [Example]

[0037] The present invention will be described in more detail below with reference to examples, but interpretation of the present disclosure is not limited to these examples. Unless otherwise specified, evaluations were performed in a laboratory at 23°C / 50% RH (relative humidity).

[0038] A metal-resin composite molded product 10 (hereinafter referred to as "test piece 10") having the shape shown in FIG. 1 was prepared as a test piece. As shown in Fig. 1, the test piece 10 is a cylinder with a quadrilateral notch in the center, and is composed of a resin molded product 12 having a cylindrical portion with a smaller outer diameter extending downward from the cylinder, and a metal member 11 placed in the inner hole of the resin molded product 12. The resin molded product 12 has an outer diameter of φ43.5 mm and a thickness of 6 mm, and the cylindrical portion extending downward has an outer diameter of φ2 mm and a thickness of 5 mm.

[0039] The metal member 11 was made of aluminum A5052 (length 35 mm, width 3.5 mm, thickness 1.3 mm) formed into a strip shape. The resin molded product 12 was made of one of the following thermoplastic resins. Liquid crystal polymer (LCP) (LAPEROS (registered trademark) HA475 (manufactured by Polyplastics Co., Ltd.)) Polyphenylene sulfide (PPS) (Durafide (registered trademark) 1140A6 (manufactured by Polyplastics Co., Ltd.)) Polybutylene terephthalate (PBT) (Duranex (registered trademark) 531HS (manufactured by Polyplastics Co., Ltd.))

[0040] <Surface treatment of metal components> The above metal member 11 was immersed in a 5% sodium hydroxide solution at 60°C for about 1 minute, then washed with water, neutralized by immersing in a 15% nitric acid aqueous solution for about 30 seconds, washed with water, and then anodized to form a large number of holes of about 10 to 100 nm in size, followed by drying.

[0041] <Manufacturing of composite molded products> The surface-treated metal member 11 was inserted into an injection molding die and injection molded under the following molding conditions to obtain an aluminum resin composite molded product. Injection molding machine: Sodick (TR100EH) Cylinder temperature: HA475: 350℃, 1140A6: 320℃, 531HS: 260℃ Thermoplastic resin and mold temperature used: HA475: 100℃, 1140A6: 140℃, 531HS: 80℃ ·Injection speed: 15mm / s - Holding pressure: 80MPa

[0042] The following impregnating agents, shrinkage inhibitors (A), adhesion promoters (B), and silicone compounds were used. <Impregnating agent> The impregnating agent used was one of the following: EPK3: Epoxy-based impregnating agent (viscosity at 25°C: 825 mPa·s) J1: Acrylic impregnating agent (viscosity at 25°C: 35 mPa·s) J4: Acrylic impregnating agent (viscosity at 25°C: 50 mPa·s) PS403E: Acrylic impregnating agent (viscosity at 25°C: 9 mPa·s) <Shrinkage inhibitor (A)> Spherical silica particles (Shin-Etsu Chemical Co., Ltd., "QSG-10", average particle size 0.015 μm) <Adhesion imparting agent (B)> 2,4-Diamino-6-triethoxysilylalkyl, 1,3,5-triazine (manufactured by Shikoku Chemicals Corporation, "VD-5") <Silicone compounds> Silicone powder (Shin-Etsu Silicone Co., Ltd., silicone composite powder "X-52-7030")

[0043] <Adjustment of impregnation agent> When a shrinkage inhibitor (A), an adhesion promoter (B), or a silicone compound was added to each of the impregnating agents, 1 part by mass of each was added to 100 parts by mass of the impregnating agent and stirred at room temperature to prepare the impregnating agent. <Penetration and hardening of impregnating agent> The impregnation and hardening of the aluminum resin composite molded product with the impregnating agent were carried out under the following conditions. ·Infiltration conditions The aluminum resin composite molded product was placed in a vacuum pressure impregnation device, and after evacuating to less than 1 kPa for 10 minutes, each impregnation agent was added and then pressurized at 0.5 MPa for 10 minutes. ·Curing conditions After immersion, each aluminum resin composite molded article was cured in a thermostatic chamber at 90°C for 0.17 hours or at 200°C for 4 hours to obtain each test piece 10. A photograph of the test piece is shown in Figure 2.

[0044] <Airtightness evaluation> An airtightness test was carried out on each of the test pieces 10 molded as the example and comparative example. The configuration of a test device for the airtightness test (helium leak test, vacuum method) is shown in FIG. As shown in Figure 3, a jig 2 and a test piece 10 are placed in a chamber 3 that is sealed from the outside. The jig 2 is a rectangular parallelepiped with a bottom, and by placing the test piece 10 on top, the inside of the jig 2 is sealed from the rest of the chamber 3. With the valve 6 open, a vacuum is created inside the jig 2 using a vacuum pump 5. Then, with the valve 6 closed, the chamber 3 is filled with helium gas using a helium cylinder 4. Helium gas leaking from the joint of the test piece 10 inside the chamber 3 is detected by a helium detector 7. A control device 8 displays the helium gas detection result. As the helium detector 7, a helium leak tester "G-FINE" manufactured by Cosmo Instruments Co., Ltd. and "L300i" manufactured by Inficon Co., Ltd. were used. The helium pressure in chamber 3 was set to 400 kPa, and the vacuum pressure in jig 2 was set to 100 kPa. If the airtightness of the joint between metal member 11 and resin molded product 12 of test piece 10 is low, helium gas in chamber 3 will flow into jig 2 and be detected by helium detector 7. In this test, the helium pressure detected by helium detector 7 (detected pressure) was measured.

[0045] A part of each test piece 10 was further subjected to the following durability treatments 1 and 2, and the above-mentioned airtightness evaluation was carried out again. <Durability treatment 1> Reflow processing The test pieces prepared in

[0043] above were treated using a conveyor-type hot air circulation dryer "DFC-27022S" manufactured by Futaba Chemical Co., Ltd., with the temperature set to a peak temperature of 255°C x 11 seconds, the conveyor speed set to 0.45 mm / min, and the passage time in the furnace set to 5 minutes. <Durability Treatment 2> -Cold-heat cycle treatment The test specimen prepared in

[0043] above was subjected to 96 cycles of treatment using a heat shock testing device "ES-76LH" manufactured by Hitachi, Ltd., with one cycle being -40°C⇔120°C (30 minutes each). The results are shown in Tables 1 and 2.

[0046] [Table 1]

[0047] [Table 2]

[0048] As shown in Tables 1 and 2, each test piece 10 of the example satisfying the configurations of the first to third embodiments had a helium detection pressure of 1×10 -11 (=1.00E-11)Pa·m 3 On the other hand, for each of the test pieces 10 of the comparative examples that do not satisfy the configurations of the first to third embodiments, the detected helium pressure was 5×10 -5 (=5.00E-5)Pa·m 3 / s. Furthermore, in each of the test pieces 10 of the examples satisfying the configurations of the first to third embodiments, no significant change occurred in the detected helium pressure even after any of the durability treatments that adversely affect airtightness. As described above, it has been found that the method according to the first embodiment can improve the airtightness of a composite molded article in which a metal member is insert-molded with a thermoplastic resin composition, that the composite molded article according to the second embodiment has even better airtightness, and that the method for manufacturing a composite molded article according to the third embodiment can manufacture a composite molded article with even better airtightness. In other words, it has been found that it is possible to provide a method for improving the airtightness of a composite molded article, a composite molded article with excellent airtightness, and a method for manufacturing the same, without being limited to the use of a thermoplastic resin that has high adhesion to metal. [Explanation of symbols]

[0049] 2 Jig 3 chambers 4 helium tanks 5. Vacuum pump 6 valves 7. Helium detector 8 Control Device 10 test specimens 11 Metallic parts 12 Resin molded products

Claims

1. A method for improving the airtightness of a composite molded article in which at least a portion of a metal member is embedded in a thermoplastic resin composition, the method comprising: The method includes infiltrating an impregnating agent into an interface between the metal member and the thermoplastic resin composition of the composite molded product, and curing the impregnating agent, the impregnating agent contains, relative to 100 parts by mass of the impregnating agent, from 0 to 10 parts by mass of a shrinkage inhibitor (A) having an average particle size (D50) of from 0.01 μm to 5 μm as measured by a laser diffraction scattering method; from 0 to 10 parts by mass of an adhesion imparting agent (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof; and the total amount of the shrinkage inhibitor (A) and the adhesion imparting agent (B) is more than 0 to 20 parts by mass, relative to 100 parts by mass of the impregnating agent.

2. The method of claim 1 , wherein the shrinkage-reducing agent (A) comprises spherical silica particles.

3. The method of claim 1 or 2, wherein the adhesion promoter (B) comprises a triazine compound containing a trialkoxysilyl group.

4. 3. The method according to claim 1 or 2, wherein the impregnating agent is an acrylic impregnating agent and / or a polyester impregnating agent.

5. The method of claim 1 or 2, wherein the impregnating agent further comprises a silicone compound.

6. The method according to claim 1 or 2, wherein the metal member has been surface-treated by one or more methods selected from the group consisting of physical roughening, chemical roughening, and surface activation.

7. The method according to claim 6, wherein the surface activation is one or more selected from the group consisting of oxygen-containing film formation, hydroxyl-containing film formation, nitrogen-containing film formation, and electromagnetic wave irradiation.

8. 3. The method according to claim 1 or 2, wherein the thermoplastic resin composition contains, per 100 parts by mass of the thermoplastic resin, 0 parts by mass or more and 100 parts by mass or less of a fibrous filler, and 10 parts by mass or more and 100 parts by mass or less of one or more non-fibrous fillers selected from a plate-like filler, a spherical filler, a powdery filler, a curved filler, and an irregular filler.

9. 3. The method of claim 1, wherein the impregnating step is performed by vacuum pressure impregnation.

10. 3. The method of claim 1 or 2, wherein curing the impregnating agent is performed by heating.

11. A composite molded article in which at least a part of a metal member is embedded in a thermoplastic resin composition, At the interface between the metal member and the thermoplastic resin composition, A shrinkage inhibitor (A) having an average particle diameter (D50) measured by a laser diffraction scattering method of 0.01 μm or more and 5 μm or less, and / or an adhesion promoter (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof; Composite molded products including:

12. The molded composite article according to claim 11, wherein the shrinkage inhibitor (A) comprises spherical silica particles.

13. A method for producing a composite molded article in which at least a part of a metal member is embedded in a thermoplastic resin composition, comprising: The manufacturing method includes: insert-molding the metal member with the thermoplastic resin composition; After the insert molding, an impregnating agent is infiltrated into the interface between the metal member and the thermoplastic resin composition, and the impregnating agent is cured. the impregnating agent contains, relative to 100 parts by mass of the impregnating agent, from 0 to 10 parts by mass of a shrinkage inhibitor (A) having an average particle size (D50) of from 0.01 μm to 5 μm as measured by a laser diffraction scattering method; from 0 to 10 parts by mass of an adhesion imparting agent (B) containing a compound having one or more functional groups selected from a hydroxy group, an amino group, an azide group, an alkoxy group, a carboxy group, a triazine ring, and derivatives thereof; and the shrinkage inhibitor (A) and the adhesion imparting agent (B) in total in an amount of more than 0 to 20 parts by mass, relative to 100 parts by mass of the impregnating agent.

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