Waterproof member, electronic device provided with the same, method for embedding a molded body, and method for waterproofing an electronic device

Abstract

This application relates to waterproof components and electronic devices having the same, waterproofing methods for embedded bodies, and waterproofing methods for electronic devices. One waterproof component is an embedded body comprising a thermoplastic resin composition and a metal component. The thermoplastic resin composition comprises a thermoplastic resin (A) and an inorganic fibrous reinforcing material (B). The content of the inorganic fibrous reinforcing material (B) is 8 to 130 parts by weight relative to 100 parts by weight of the thermoplastic resin (A), and the average fiber diameter of the inorganic fibrous reinforcing material (B) is 10 μm or less, and the average fiber length is 300 μm or less.

Description

[0001] This application is a divisional application of the application filed on October 26, 2018, with application number 201880070007.7 and entitled "Waterproof component and electronic device having the same, waterproof method of embedded body and waterproof method of electronic device". Technical Field

[0002] This invention relates to waterproof components and electronic devices having the same, waterproofing methods for embedded molded bodies, and waterproofing methods for electronic devices. Background Technology

[0003] In recent years, there has been an increasing demand for waterproofing in electronic devices such as smartphones. The external connection terminals of these devices are typically composites of resin, resin compositions, and metal components, with the metal components often exposed. Therefore, waterproofing at the interface between the resin, resin composition, and metal has become a challenge. Previously, methods using sealing materials such as elastomers were known as waterproofing methods for these external connection terminals (Patent Document 1, etc.). However, these methods have drawbacks, including the inability to manufacture the component in a single step due to the installation of the elastomer, difficulties in miniaturization, and the cost associated with the elastomer itself or its installation process.

[0004] Therefore, a method for manufacturing waterproof components by injection molding resin or resin composition into metal parts embedded in a mold and integrally joining them has been proposed (Patent Documents 2, 3, etc.).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2002-33155

[0008] Patent Document 2: Japanese Patent Application Publication No. 2012-59381

[0009] Patent Document 3: Japanese Patent Application Publication No. 2016-81737

[0010] Patent Document 4: Japanese Patent Application Publication No. 2014-141630 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] However, in general, the expansion and contraction characteristics of metal parts are significantly different from those of resins or resin compositions. This is especially true for inserts made using resin compositions containing glass fibers. During the insert molding process, reflow soldering process, and subsequent cooling process, stresses corresponding to the difference in expansion and contraction characteristics are generated, which can easily create tiny gaps between the metal parts and the resin or resin composition, leaving issues related to water resistance.

[0013] That is, the objective of the present invention is to provide a waterproof component as an embedded molded body that has sufficient waterproofness even after undergoing heating processes such as reflow soldering, and an electronic device having the same.

[0014] Methods for solving problems

[0015] Through in-depth research, the inventors discovered that in an embedded molded body comprising a thermoplastic resin composition and a metal component, i.e. a waterproof component, the waterproofness is improved by adding a specified amount of a specified inorganic fibrous reinforcing material to the thermoplastic resin used. Based on this insight, the inventors conducted further and repeated research, thereby completing the present invention.

[0016] This invention relates to the following [1] to

[17] .

[0017] [1] A waterproof component comprising an insert molded body containing a thermoplastic resin composition and a metal component,

[0018] The thermoplastic resin composition comprises a thermoplastic resin (A) and an inorganic fibrous reinforcing material (B).

[0019] The content of inorganic fibrous reinforcing material (B) is 8 to 130 parts by weight relative to 100 parts by weight of thermoplastic resin (A).

[0020] The inorganic fibrous reinforced material (B) has an average fiber diameter of less than 10 μm and an average fiber length of less than 300 μm.

[0021] [2] According to the waterproof component described in [1], the thermoplastic resin (A) has a melting point or glass transition temperature of 130°C or higher.

[0022] [3] The waterproof component according to [1] or [2], wherein the thermoplastic resin (A) has a melting point of 280°C or higher.

[0023] [4] The waterproof component according to any one of [1] to [3], wherein the thermoplastic resin (A) is selected from at least one of liquid crystal polymer, polycarbonate, polyphenylene sulfide and polyamide.

[0024] [5] According to the waterproof component described in [4], the thermoplastic resin (A) is a polyamide in which 50 to 100 mol% of the diamine unit is an aliphatic diamine unit with 4 to 18 carbon atoms.

[0025] [6] The waterproof component according to any one of [1] to [5], wherein the inorganic fibrous reinforcing material (B) is selected from at least one of wollastonite, potassium titanate whiskers and ground fibers.

[0026] [7] The waterproof component according to [6], wherein the inorganic fibrous reinforcing material (B) is wollastonite.

[0027] [8] The waterproof component according to any one of [1] to [7] is used for a purpose applicable to a surface mounting process.

[0028] [9] The waterproof component according to any one of [1] to [8] is an external connection terminal.

[0029]

[10] The waterproof component according to any one of [1] to [8] is a switch.

[0030]

[11] An electronic device comprising any of the waterproof components described in any one of [1] to

[10] .

[0031]

[12] The electronic device described in

[11] is a portable electronic device.

[0032]

[13] A method for waterproofing an embedded molded body comprising a thermoplastic resin composition and a metal component,

[0033] The insert is made using the following thermoplastic resin composition.

[0034] The thermoplastic resin composition comprises a thermoplastic resin (A) and an inorganic fibrous reinforcing material (B).

[0035] The content of inorganic fibrous reinforcing material (B) is 8 to 130 parts by weight relative to 100 parts by weight of thermoplastic resin (A).

[0036] The inorganic fibrous reinforced material (B) has an average fiber diameter of less than 10 μm and an average fiber length of less than 300 μm.

[0037]

[14] Use of a thermoplastic resin composition for waterproofing an insert comprising a thermoplastic resin composition and a metal part, the thermoplastic resin composition comprising a thermoplastic resin (A) and an inorganic fibrous reinforcing material (B).

[0038] The content of inorganic fibrous reinforcing material (B) is 8 to 130 parts by weight relative to 100 parts by weight of thermoplastic resin (A).

[0039] The inorganic fibrous reinforced material (B) has an average fiber diameter of less than 10 μm and an average fiber length of less than 300 μm.

[0040]

[15] A method for waterproofing an electronic device, wherein the waterproof component described in any one of [1] to [8] is used as an external connection terminal.

[0041]

[16] A method for waterproofing an electronic device, wherein the waterproof component described in any one of [1] to [8] is used as a switch.

[0042]

[17] A method for manufacturing a waterproof component, wherein a thermoplastic resin composition is embedded in a metal component, wherein the thermoplastic resin composition is obtained by melt-blending an inorganic fibrous reinforcing material (B) with an average fiber diameter of less than 10 μm and an average fiber length of less than 300 μm with an amount of 8 to 130 parts by weight relative to 100 parts by weight of thermoplastic resin (A).

[0043] The effects of the invention

[0044] The present invention provides a waterproof component as an embedded molded body that has sufficient waterproofness even after undergoing heating processes such as reflow soldering, and an electronic device equipped with the same. Attached Figure Description

[0045] Figure 1 This is a photograph of the molded article used in the red ink test of the embodiment. The external dimensions of the molded article are 2.8 mm in width, 3.0 mm in depth, and 1.3 mm in thickness.

[0046] Figure 2 This refers to a photo that was determined to be "leaking" during the red ink test in the embodiment. Detailed Implementation

[0047] The present invention will now be described in detail.

[0048] The waterproof component of the present invention is an embedded molded body comprising a thermoplastic resin composition and a metal component. The thermoplastic resin composition comprises a thermoplastic resin (A) and an inorganic fibrous reinforcing material (B). The content of the inorganic fibrous reinforcing material (B) is 8 to 130 parts by weight relative to 100 parts by weight of the thermoplastic resin (A). The inorganic fibrous reinforcing material (B) has an average fiber diameter of 10 μm or less and an average fiber length of 300 μm or less.

[0049] By using the above-described thermoplastic resin composition, the water resistance of the embedded molded body (at the interface between the thermoplastic resin composition and the metal) comprising the thermoplastic resin composition and the metal part is improved, and the water resistance of the waterproof part becomes sufficient.

[0050] The reason is not yet determined, but it can be assumed that this is because: by using the above-mentioned thermoplastic resin composition, the stress of the resin composition remaining after the embedding molding process and the heating process can be relaxed, and gaps can be prevented at the joint surface between the thermoplastic resin composition and the metal.

[0051] (Thermoplastic resin (A))

[0052] The thermoplastic resin (A) used in this invention is not particularly limited as long as it can impart the above-mentioned effects, and examples include: polycarbonate; polyphenylene ether; polyphenylene sulfide (PPS); polysulfone; polyethersulfone; polyarylate; cyclic polyolefin; polyetherimide; polyamide; polyamideimide; polyimide; liquid crystal polymers such as aromatic polyesters and aromatic polyesteramides; polyaminobismaleimide; polyetheretherketone, etc.

[0053] From the viewpoint of dimensional stability and heat resistance, the preferred material is at least one selected from liquid crystal polymers, polycarbonate, PPS and polyamide, more preferably PPS and polyamide, and even more preferably polyamide.

[0054] Furthermore, from the viewpoints of water resistance, heat resistance and formability, the melting point or glass transition temperature of the thermoplastic resin (A) is preferably 130°C or higher.

[0055] It should be noted that, in this invention, "melting point or glass transition temperature of 130°C or higher" means that at least one of the melting point and glass transition temperature is 130°C or higher. From the viewpoint of heat resistance and formability, the melting point or glass transition temperature of the thermoplastic resin (A) is more preferably 150°C or higher, and even more preferably 170°C or higher. From the viewpoint of preventing thermal decomposition of the resin during molding, the melting point or glass transition temperature of the thermoplastic resin (A) is preferably 350°C or lower, and more preferably 320°C or lower. The melting point and glass transition temperature in this invention are determined using the methods described in the examples.

[0056] The melting point of the thermoplastic resin (A) is preferably 280°C or higher, more preferably 285°C or higher, and even more preferably 295°C or higher. If the melting point of the thermoplastic resin (A) is above the above temperature, then even if the waterproof component containing the thermoplastic resin (A) is used for applications involving exposure to heating processes such as reflow soldering, sufficient waterproofness can be maintained.

[0057] (Polyamide)

[0058] The polyamides described above preferably have dicarboxylic acid units and diamine units.

[0059] Examples of dicarboxylic acid units include: aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, dimethylmalonic acid, 2,2-diethylsuccinic acid, 2,2-dimethylglutaric acid, 2-methyl adipic acid, and trimethyl adipic acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, cycloheptanedicarboxylic acid, cyclooctanedicarboxylic acid, and cyclodecanedicarboxylic acid; and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, biphenyl acid, 4,4'-biphenyldicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, and diphenyl sulfone-4,4'-dicarboxylic acid. These units can be one or more types.

[0060] In addition, the polyamides described above may also contain structural units of ternary or higher polycarboxylic acids such as trimellitic acid, pyromellitic acid, and pyromellitic tetracarboxylic acid, within a range capable of being melt-formed without impairing the effects of the present invention.

[0061] As the aforementioned polyamide, polyamides in which 50 to 100 mol% of the diamine unit is an aliphatic diamine unit having 4 to 18 carbon atoms are preferred, polyamides in which 60 to 100 mol% of the diamine unit is an aliphatic diamine unit having 4 to 18 carbon atoms are more preferred, and polyamides in which 90 to 100 mol% of the diamine unit is an aliphatic diamine unit having 4 to 18 carbon atoms are even more preferred.

[0062] Examples of aliphatic diamine units with 4 to 18 carbon atoms include those derived from 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,4-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, and 1,18-octadecanediamine. Linear aliphatic diamines such as alkyldiamines; 1,1-dimethyl-1,4-butanediamine, 1-ethyl-1,4-butanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 1,4-dimethyl-1,4-butanediamine, 2,3-dimethyl-1,4-butanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 3,3-dimethyl-1,4-butanediamine, etc. Methyl-1,6-hexanediamine, 2,2-dimethyl-1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2,4-diethyl-1,6-hexanediamine, 2,2-dimethyl-1,7-heptanediamine, 2,3-dimethyl-1,7-heptanediamine, 2,4-dimethyl-1,7-heptanediamine, 2,5-dimethyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, 3-methyl-1,8-octanediamine Structural units of branched aliphatic diamines such as 4-methyl-1,8-octanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8-octanediamine, 2,4-dimethyl-1,8-octanediamine, 3,4-dimethyl-1,8-octanediamine, 4,5-dimethyl-1,8-octanediamine, 2,2-dimethyl-1,8-octanediamine, 3,3-dimethyl-1,8-octanediamine, 4,4-dimethyl-1,8-octanediamine, and 5-methyl-1,9-nonanediamine. These units can be one or two or more types.

[0063] Preferably, the structural unit is selected from at least one of the structural units chosen from 1,4-butanediamine, 1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 1,8-octanediamine, 2-methyl-1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine; more preferably, the structural unit is selected from at least one of the structural units chosen from 1,4-butanediamine, 1,6-hexanediamine, 1,9-nonanediamine, 2-methyl-1,8-octanediamine, and 1,10-decanediamine.

[0064] When the diamine unit contains both structural units from 1,9-nonanediamine and structural units from 2-methyl-1,8-octanediamine, the molar ratio of the structural units from 1,9-nonanediamine to those from 2-methyl-1,8-octanediamine is preferably in the range of 95 / 5 to 40 / 60, more preferably in the range of 90 / 10 to 50 / 50.

[0065] In addition, depending on the application, it is sometimes preferred that the ratio of structural units from 1,9-nonanediamine to structural units from 2-methyl-1,8-octanediamine be in the range of 55 / 45 to 45 / 55.

[0066] The diamine unit in the aforementioned polyamide may include diamine units other than aliphatic diamine units with 4 to 18 carbon atoms, without impairing the effects of the present invention. Examples of such diamine units include: aliphatic diamines such as ethylenediamine, 1,2-propanediamine, and 1,3-propanediamine; alicyclic diamines such as cyclohexanediamine, methylcyclohexanediamine, isophorone diamine, norbornene dimethylamine, and tricyclodecane dimethyldiamine; and aromatic diamines such as p-phenylenediamine, m-phenylenediamine, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenyl ether. These units may be one or more types.

[0067] The aforementioned polyamide may contain aminocarboxylic acid units. Examples of aminocarboxylic acid units include lactams such as caprolactam and laurolactam, and units derived from aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid. The content of aminocarboxylic acid units in the aforementioned polyamide is preferably 40 mol% or less, more preferably 20 mol% or less, relative to the total 100 mol% of dicarboxylic acid units and diamine units in the aforementioned polyamide.

[0068] The polyamide described above may contain units derived from the capping agent. The units derived from the capping agent are preferably 1.0 to 10 mol% relative to the diamine units, more preferably 2.0 to 7.5 mol%, and even more preferably 2.5 to 6.5 mol%.

[0069] To achieve the desired unit content from the end-capping agent, the polymerization feedstock can be fed in a manner that ensures the end-capping agent reaches the desired range relative to the diamine. It should be noted that, considering the volatilization of monomer components during polymerization, it is preferable to fine-tune the amount of end-capping agent added to the polymerization feedstock to introduce the desired amount of unit content from the end-capping agent into the resulting resin.

[0070] As a method for determining the content of units from the end-capping agent in the aforementioned polyamide, examples include: as shown in Japanese Patent Application Publication No. 07-228690, measuring the solution viscosity, calculating the total amount of terminal groups from its relationship with the number-average molecular weight, and subtracting the amount of amino and carboxyl groups determined by titration from it; using 1 Methods such as H-NMR, which calculate based on the integral values ​​of signals corresponding to the diamine unit and the unit from the capping agent, respectively.

[0071] As capping agents, monofunctional compounds that react with terminal amino or terminal carboxyl groups can be used. Specifically, examples include monocarboxylic acids, acid anhydrides, monoisocyanates, monoacyl halides, monoesters, monoalcohols, and monoamines. From the viewpoints of reactivity and stability of the capping end, monocarboxylic acids are preferred as capping agents targeting the terminal amino group, and monoamines are preferred as capping agents targeting the terminal carboxyl group. Furthermore, from the viewpoint of ease of handling, monocarboxylic acids are more preferred as capping agents.

[0072] The monocarboxylic acid used as a capping agent is not particularly limited as long as it has the reactivity to react with an amino group. Examples include: aliphatic monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, tervaric acid, and isobutyric acid; alicyclic monocarboxylic acids such as cyclopentanecarboxylic acid and cyclohexanecarboxylic acid; aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthoic acid, β-naphthoic acid, methylnaphthoic acid, and phenylacetic acid; and any mixture thereof. Among these, from the viewpoints of reactivity, capping stability, and price, at least one of acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, and benzoic acid is preferred.

[0073] The monoamine used as a capping agent is not particularly limited as long as it has the reactivity to react with a carboxyl group. Examples include aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine, and naphthylamine; and any mixture thereof. Among these, from the viewpoints of reactivity, high boiling point, stability of the capped end, and price, at least one of butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline is preferred.

[0074] The polyamides described above can be manufactured using any method known as a method for manufacturing polyamides. For example, they can be manufactured by solution polymerization or interfacial polymerization using acyl chlorides and diamines as raw materials, melt polymerization using dicarboxylic acids and diamines as raw materials, solid-state polymerization, and melt extrusion polymerization.

[0075] The aforementioned polyamide can be manufactured, for example, by first adding diamine, dicarboxylic acid, and a catalyst and end-capping agent as needed to produce a nylon salt, then heating and polymerizing at a temperature of 200–250°C to produce a prepolymer, followed by solid-state polymerization or polymerization using a melt extruder. When performing the final stage of polymerization via solid-state polymerization, it is preferable to carry out the polymerization under reduced pressure or with a flow of inert gas. If the polymerization temperature is in the range of 200–280°C, the polymerization rate is high, the productivity is excellent, and coloring and gelation can be effectively suppressed. As for the polymerization temperature during the final stage of polymerization via a melt extruder, it is preferably below 370°C. If polymerization is carried out under these conditions, decomposition is almost nonexistent, and polyamide with minimal deterioration can be obtained.

[0076] Examples of catalysts that can be used in the manufacture of the aforementioned polyamides include, for example, phosphoric acid, phosphorous acid, hypophosphite, and their salts or esters. Examples of such salts or esters include: salts formed from phosphoric acid, phosphorous acid, or hypophosphite with metals such as potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium, and antimony; ammonium salts of phosphoric acid, phosphorous acid, or hypophosphite; and ethyl, isopropyl, butyl, hexyl, isodecyl, octadecyl, decyl, stearyl, and phenyl esters of phosphoric acid, phosphorous acid, or hypophosphite.

[0077] In addition, the polyamides mentioned above can be any of crystalline polyamides, amorphous polyamides, or mixtures thereof.

[0078] Examples of the aforementioned crystalline polyamides include: polyhexamethylene adipamide (polyamide 6), polyhexamethylene adipamide (polyamide 66), polybutadiene adipamide (polyamide 46), polyhexamethylene sebacate (polyamide 610), polyhexamethylene dodecanoate (polyamide 612), polyundecanoate diamine (polyamide 116), polydodecanoate bis(4-aminocyclohexyl)methane (polyamide PACM12), polydodecanoate bis(3-methyl-4-aminocyclohexyl)methane (polyamide dimethyl PACM12), polyundecanoate diamine (polyamide 11T), and polyhexahydro-terephthaloate undecanoate diamine (polyamide 1). Polyamides include poly(1T(H)), polyundecylamide (polyamide 11), polydodecylamide (polyamide 12), poly(trimethylhexamethylene terephthalamide) (polyamide TMDT), poly(m-phenylene adipamide) (polyamide MXD6), poly(hexamethylene terephthalamide) (polyamide 6T), poly(nonadiamine terephthalamide) (polyamide 9T), poly(decylamine terephthalamide) (polyamide 10T), poly(hexamethylene isophthalamide) (polyamide 6I), copolymers of polyamide 6I and polyamide 6T (polyamide 6I / 6T), and copolymers of polyamide 6T and polyundecylamide (polyamide 11) (polyamide 6T / 11), as well as copolymers or mixtures thereof. It should be noted that the above-mentioned crystalline polyamides also include substances obtained by substituting the benzene ring of terephthalic acid and / or isophthalic acid with alkyl or halogen atoms.

[0079] Among the aforementioned crystalline polyamides, polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 46, polyamide 6T, polyamide 9T, and polyamide 10T are preferred; more preferably, polyamide 6, polyamide 66, polyamide 46, polyamide 6T, polyamide 9T, and polyamide 10T are preferred; and even more preferably, polyamide 46, polyamide 6T, polyamide 9T, and polyamide 10T are preferred. The aforementioned crystalline polyamides can be used alone or in combination.

[0080] Examples of the aforementioned amorphous polyamides include: condensation polymers of terephthalic acid / isophthalic acid / 1,6-hexanediamine; condensation polymers of terephthalic acid / isophthalic acid / 1,6-hexanediamine / bis(3-methyl-4-aminocyclohexyl)methane; condensation polymers of terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine; and isophthalic acid / iso ... Condensation polymers of dicarboxylic acid / bis(3-methyl-4-aminocyclohexyl)methane / ω-laurolamide, isophthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, and terephthalic acid / isophthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, etc. It should be noted that the above-mentioned amorphous polyamides also include substances obtained by substituting the benzene rings of terephthalic acid and / or isophthalic acid with alkyl or halogen atoms.

[0081] Among the aforementioned amorphous polyamides, preferred are condensation polymers of terephthalic acid / isophthalic acid / 1,6-hexanediamine, terephthalic acid / isophthalic acid / 1,6-hexanediamine / bis(3-methyl-4-aminocyclohexyl)methane, and terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine; more preferably, condensation polymers of terephthalic acid / isophthalic acid / 1,6-hexanediamine and terephthalic acid / isophthalic acid / 1,6-hexanediamine / bis(3-methyl-4-aminocyclohexyl)methane. The aforementioned amorphous polyamides can be used alone or in combination.

[0082] (Inorganic fibrous reinforced material (B))

[0083] Examples of inorganic fibrous reinforcing materials (B) used in this invention include: wollastonite, potassium titanate whiskers, calcium carbonate whiskers, aluminum borate whiskers, magnesium sulfate whiskers, sepiolite, calcareous silica, zinc oxide whiskers, ground fibers, and shredded fibers. One type may be used alone, or two or more may be used in combination.

[0084] Among the aforementioned inorganic fibrous reinforcing materials (B), at least one is preferably selected from wollastonite, potassium titanate whiskers and ground fibers, more preferably wollastonite or ground fibers, and even more preferably wollastonite.

[0085] The inorganic fibrous reinforcing material (B) used in this invention has an average fiber diameter of less than 10 μm and an average fiber length of less than 300 μm. It should be noted that the above average fiber diameter and average fiber length are values ​​before melt mixing.

[0086] From the viewpoint of water resistance, the average fiber diameter is preferably 9 μm or less, more preferably 8 μm or less, and even more preferably 7 μm or less. Furthermore, from the viewpoint of strength, the average fiber diameter is preferably 2 μm or more, more preferably 4 μm or more.

[0087] Furthermore, from the viewpoint of water resistance, the average fiber length is preferably 250 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less. From the viewpoint of strength, the average fiber length is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more.

[0088] It should be noted that the “average fiber diameter” in this specification refers to the fiber diameter when the cumulative mass is 50%, which can be determined as follows: the inorganic fibrous reinforcing material (B) is dispersed in a 0.2% sodium metaphosphate aqueous solution, and the particle size distribution is measured by X-ray permeation gravity sedimentation using a particle size distribution measuring device (such as the “SediGraph III 5120” manufactured by Micromeritics Instrument Corp.).

[0089] In addition, the “average fiber length” in this specification can be obtained as follows: the fiber lengths of 400 randomly selected inorganic fibrous reinforcing materials (B) were measured using image analysis with electron microscopy and the average weight was used to determine the length.

[0090] The content of the inorganic fibrous reinforcing material (B) relative to 100 parts by weight of the thermoplastic resin (A) is 8 to 130 parts by weight, preferably 40 to 130 parts by weight, and more preferably 45 to 110 parts by weight. It should be noted that by making the content of the inorganic fibrous reinforcing material (B) 8 parts by weight or more, sufficient reinforcing effect of the inorganic fibrous reinforcing material (B) can be obtained, and a waterproof effect can also be obtained. Furthermore, by making it 130 parts by weight or less, melt-mixing properties become good.

[0091] (Other ingredients)

[0092] The thermoplastic resin composition used in this invention may further include, without impairing the effects of this invention, heat stabilizers, light stabilizers, elastomers, lubricants, nucleating agents, crystallization delay agents, anti-hydrolysis agents, antistatic agents, free radical inhibitors, matting agents, ultraviolet absorbers, flame retardants, and inorganic substances other than the aforementioned inorganic fibrous reinforcing material (B), in addition to the thermoplastic resin (A) and inorganic fibrous reinforcing material (B). Examples of such inorganic substances include, for instance, carbon nanotubes, fullerenes, talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, silica, bentonite, aluminosilicates, silica, magnesium oxide, alumina, zirconium oxide, titanium oxide, iron oxide, calcium carbonate, magnesium carbonate, dolomite, calcium sulfate, barium sulfate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, glass fiber, glass beads, glass sheets, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black, graphite, etc. The content of other components in the thermoplastic resin composition can be set to, for example, 50% by mass or less, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0093] Furthermore, the total content of thermoplastic resin (A) and inorganic fibrous reinforcing material (B) in the thermoplastic resin composition is preferably 50% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0094] (Metal parts)

[0095] The metal used to form the metal parts in this invention is not particularly limited as long as it can be embedded and shaped. Examples include alloys such as aluminum, copper, iron, tin, nickel, zinc, aluminum alloys, and stainless steel. Their surfaces can be plated with aluminum, tin, nickel, gold, silver, etc.

[0096] (Waterproof components)

[0097] The waterproof component of the present invention can be manufactured by embedding a thermoplastic resin composition and a metal component, etc. The thermoplastic resin composition is obtained by melt-blending an inorganic fibrous reinforcing material (B) with an average fiber diameter of 10 μm or less and an average fiber length of 300 μm or less with 8 to 130 parts by weight relative to 100 parts by weight of thermoplastic resin (A).

[0098] When performing embedding molding, any method known as embedding molding method can be used, such as injection molding embedding method, compression molding method, etc.

[0099] It should be noted that, as needed, further processing based on ultrasonic welding, laser welding, vibration welding, thermal welding, hot melting, etc., can be carried out after the embedding and forming.

[0100] In component mounting of electronic components onto printed circuit boards (PCBs), conventional methods involve insertion mounting, which uses immersion in a molten solder bath (immersion tank) for soldering. On the other hand, in surface mounting, which has seen increased use in recent years, solder paste is printed onto the PCB, electronic components are mounted on it, and then the PCB is heated in a reflow oven, typically at 260°C, to melt the solder and bond the PCB to the electronic components. Surface mounting enables miniaturization of PCBs and increases productivity; however, during the reflow soldering process and subsequent cooling, stress arises due to the difference in expansion and contraction characteristics between the metal components and the resin or resin composition. This can easily create tiny gaps between the metal components and the resin or resin composition, making it difficult to maintain waterproofness. The waterproof component of this invention is not easily deformed even after heating processes such as reflow soldering. Therefore, it is preferably used in surface mounting processes employing such reflow soldering. It should be noted that reflow soldering and other heating processes can be applied multiple times as needed.

[0101] The waterproof component of this invention has excellent waterproof performance, and is therefore useful as an external connection terminal for FPC connectors, BtoB connectors, card connectors, SMT connectors (coaxial connectors, etc.), memory card connectors, etc.; SMT relays; SMT coils; slots such as memory slots and CPU slots; switches such as command switches and SMT switches; sensors such as rotation sensors and acceleration sensors, etc. It is especially useful as a switch or external connection terminal for electronic devices, particularly as a switch.

[0102] When the waterproof component of the present invention is used as a switch, and the external dimensions of the embedded molded body comprising the thermoplastic resin composition and the metal component are set as width × depth × thickness, the width is preferably 15 mm or less, more preferably 10 mm or less, and even more preferably 5 mm or less; the depth is preferably 50 mm or less, more preferably 25 mm or less, and even more preferably 5 mm or less; and the thickness is preferably 50 mm or less, more preferably 15 mm or less, and even more preferably 3 mm or less. It should be noted that the depth of the external dimensions is set to be longer than the width.

[0103] In particular, by using the waterproof component of the present invention as a switch or external connection terminal, electronic devices can be effectively waterproofed.

[0104] Examples of electronic devices equipped with the waterproof component of the present invention include, but are not limited to, portable electronic devices such as digital cameras and smartphones.

[0105] Example

[0106] The present invention will be described in more detail below through embodiments, but the present invention is not limited to the embodiments described herein.

[0107] It should be noted that the melting point and glass transition temperature of the thermoplastic resin (A) used in the examples and comparative examples were determined according to the method shown below.

[0108] (Melting point and glass transition temperature of thermoplastic resin (A))

[0109] The melting point of the polyamides (PA9T and PA46, described below) used as thermoplastic resins (A) was determined as follows: The melting point (°C) was determined by using a differential scanning calorimeter (DSC822) manufactured by MetTLER TOLEDO, under a nitrogen atmosphere, where the temperature was increased from 30°C to 360°C at a rate of 10°C / min. It should be noted that when multiple melting peaks exist, the peak temperature of the highest melting peak is taken as the melting point.

[0110] Subsequently, the sample was completely melted by holding it at a temperature 30°C higher than the melting point for 10 minutes, then cooled to 40°C at a rate of 10°C / min, and held at 40°C for 10 minutes. The temperature was then increased again at a rate of 10°C / min to a temperature 30°C higher than the melting point, and the midpoint of the step-like change in the DSC curve at this point was set as the glass transition temperature.

[0111] Examples 1-6 and Comparative Examples 1-3

[0112] Thermoplastic resin (A) as shown in Table 1, along with antioxidants, release agents, and nucleating agents, are supplied from the upstream hopper to a twin-screw extruder (screw diameter 32 mm φ, L / D = 30, rotation speed 150 rpm, ejection rate 10 kg / h) manufactured by the Plastics Engineering Research Institute. Additionally, inorganic fibrous reinforcing material (B) as shown in Table 1 is supplied from the side feeder for melt mixing. The melt-mixed thermoplastic resin composition is extruded into strands, cooled, and then cut to obtain granules of the thermoplastic resin composition. It should be noted that the amounts of thermoplastic resin (A) and inorganic fibrous reinforcing material (B) in Table 1 refer to "parts by mass".

[0113] Using these granules, the following methods are used to evaluate the form of the molded articles.

[0114] [Red ink test (waterproofing test)]

[0115] Using a TR40EH injection molding machine (manufactured by SODICK), the thermoplastic resin compositions obtained in the various examples or comparative examples were injection molded into a box shape (external dimensions: width 2.8 mm, depth 3.0 mm, thickness 1.3 mm) on an LED lead frame made of nickel-plated copper base material. The box-shaped molded articles obtained above were subjected to two heat treatments using a reflow soldering apparatus with a maximum temperature of 260°C under the following reflow soldering conditions. The resulting samples were then subjected to the following red ink test.

[0116] Reflow soldering conditions: Heat the sample from 25°C to 150°C over 60 seconds, then heat to 180°C over 90 seconds, and then heat to 260°C over 60 seconds. After that, hold at 260°C for 20 seconds, then cool the sample from 260°C to 100°C over 30 seconds. Once it reaches 100°C, seal it with air and allow it to cool naturally to 23°C.

[0117] Red ink test: Red ink (LION Office Printer Red) was dropped into the interior of a mold formed from a thermoplastic resin composition. After 5 minutes, it was determined whether the ink leaked to the back of the mold. A case where the ink did not leak at all was defined as "no leakage," and a case where leakage occurred was defined as "leakage." The results are shown in Table 1.

[0118] Additionally, a photograph of the molded article used in the red ink test of the embodiment is shown. Figure 1 The image shown represents a case where "leaking" was determined during the red ink test in the embodiment. Figure 2 .

[0119] [Table 1]

[0120]

[0121] It should be noted that the components shown in Table 1 are as follows.

[0122] [Thermoplastic resin (A)]

[0123] PA9T-1: Manufactured by Kuraray Corporation, PA9T (a polyamide with dicarboxylic acid units of terephthalic acid, diamine units of 1,9-nonanediamine and 2-methyl-1,8-octanediamine (molar ratio of 85 / 15)), melting point 305℃, glass transition temperature 125℃

[0124] PA9T-2: Manufactured by Kuraray Corporation, PA9T (a polyamide with dicarboxylic acid units of terephthalic acid, diamine units of 1,9-nonanediamine and 2-methyl-1,8-octanediamine (molar ratio of 80 / 20)), melting point 301℃, glass transition temperature 125℃

[0125] PA46: “Stanyl TW341”, manufactured by DSM Japan, PA46 (a polyamide with adipic acid unit as the main dicarboxylic acid unit and 1,4-butanediamine unit as the main diamine unit), melting point 295℃, glass transition temperature 75℃

[0126] [Inorganic fibrous reinforcing materials (B)]

[0127] • Wollastonite: "SH1250", manufactured by KINSEIMATEC, with an average fiber diameter of 5.3 μm, an average fiber length of 85 μm, and an aspect ratio of 16:1.

[0128] • Glass fiber: “CS3J256S”, manufactured by Nitto Boki Co., Ltd., with an average fiber diameter of 11μm and an average fiber length of 3mm.

[0129] As shown in Table 1, a comparison between the embodiments and comparative examples shows that the waterproof component of the present invention exhibits excellent waterproof performance after the reflow soldering process.

[0130] Industrial availability

[0131] According to the present invention, a waterproof component as an embedded molded body can be provided that maintains sufficient waterproofness even after undergoing heating processes such as reflow soldering. This waterproof component is particularly useful as an external connection terminal for electronic devices.

Claims

1. A waterproof component, comprising an insert molded body containing a thermoplastic resin composition and a metal component, The thermoplastic resin composition comprises a thermoplastic resin (A) and an inorganic fibrous reinforcing material (B). The content of inorganic fibrous reinforcing material (B) is 8 to 130 parts by weight relative to 100 parts by weight of thermoplastic resin (A). The inorganic fibrous reinforced material (B) has an average fiber diameter of less than 10 μm and an average fiber length of less than 300 μm. The inorganic fibrous reinforcing material (B) is wollastonite.

2. The waterproof component according to claim 1, wherein, The melting point or glass transition temperature of the thermoplastic resin (A) is above 130°C.

3. The waterproof component according to claim 1 or 2, wherein, Thermoplastic resin (A) has a melting point above 280°C.

4. The waterproof component according to any one of claims 1 to 3, wherein, The thermoplastic resin (A) is selected from at least one of liquid crystal polymers, polycarbonate, polyphenylene sulfide and polyamide.

5. The waterproof component according to claim 4, wherein, Thermoplastic resin (A) is a polyamide in which 50 mol% to 100 mol% of the diamine unit is an aliphatic diamine unit with 4 to 18 carbon atoms.

6. The waterproof component according to any one of claims 1 to 5, wherein, The inorganic fibrous reinforcing material (B) has an average fiber diameter of more than 2 μm and less than 10 μm.

7. The waterproof component according to any one of claims 1 to 6, wherein, The inorganic fibrous reinforcing material (B) has an average fiber length of more than 20 μm and less than 300 μm.

8. The waterproof component according to any one of claims 1 to 7, It satisfies the following characteristics, namely: Using a SODICK TR40EH injection molding machine, a thermoplastic resin composition was injection molded onto an LED lead frame made of nickel-plated copper material at a maximum temperature of 340°C, a mold temperature of 140°C, and an injection speed of 100mm / s to 200mm / s to form a box-shaped structure with dimensions of 2.8mm width, 3.0mm depth, and 1.3mm thickness. The resulting insert was then subjected to two heat treatments using a reflow soldering apparatus under the following reflow soldering conditions. Red ink, manufactured by LION Office Supplies, was then dripped into the interior of the insert. After 5 minutes, the red ink did not leak onto the back of the insert. Reflow soldering conditions: Heat the sample from 25°C to 150°C in 60 seconds, then heat to 180°C in 90 seconds, then heat to 260°C in 60 seconds, then hold at 260°C for 20 seconds, then cool the sample from 260°C to 100°C in 30 seconds. After reaching 100°C, seal in air and allow it to cool naturally to 23°C.

9. The waterproof component according to any one of claims 1 to 8, for use in a surface mounting process.

10. The waterproof component according to any one of claims 1 to 8, wherein it is an external connection terminal.

11. The waterproof component according to any one of claims 1 to 8, wherein it is a switch.

12. An electronic device comprising a waterproof component according to any one of claims 1 to 11.

13. The electronic device according to claim 12, wherein it is a portable electronic device.

14. A method for waterproofing an embedded molded body, the embedded molded body comprising a thermoplastic resin composition and a metal component, The insert is made using the following thermoplastic resin composition. The thermoplastic resin composition comprises a thermoplastic resin (A) and an inorganic fibrous reinforcing material (B). The content of inorganic fibrous reinforcing material (B) is 8 to 130 parts by weight relative to 100 parts by weight of thermoplastic resin (A). The inorganic fibrous reinforced material (B) has an average fiber diameter of less than 10 μm and an average fiber length of less than 300 μm. The inorganic fibrous reinforcing material (B) is wollastonite.

15. Use of a thermoplastic resin composition for waterproofing an insert comprising a thermoplastic resin composition and a metal part, said thermoplastic resin composition comprising a thermoplastic resin (A) and an inorganic fibrous reinforcing material (B). The content of inorganic fibrous reinforcing material (B) is 8 to 130 parts by weight relative to 100 parts by weight of thermoplastic resin (A). The inorganic fibrous reinforced material (B) has an average fiber diameter of less than 10 μm and an average fiber length of less than 300 μm. The inorganic fibrous reinforcing material (B) is wollastonite.

16. A method for waterproofing an electronic device, wherein the waterproof component according to any one of claims 1 to 8 is used as an external connection terminal.

17. A method for waterproofing an electronic device, wherein the waterproof component according to any one of claims 1 to 8 is used as a switch.

18. A method for manufacturing a waterproof component, wherein, A thermoplastic resin composition is embedded into a metal part. The thermoplastic resin composition is obtained by melt-blending an inorganic fibrous reinforcing material (B) with an average fiber diameter of less than 10 μm and an average fiber length of less than 300 μm with an amount of 8 to 130 parts by weight relative to 100 parts by weight of thermoplastic resin (A). The inorganic fibrous reinforcing material (B) is wollastonite.

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