Polyamide resin composition for reflective plate, and reflective plate

Abstract

Provided is a polyamide resin composition for a reflecting plate, which is capable of obtaining a reflecting plate having excellent adhesion to a sealant used in a light-emitting device such as an LED. The polyamide resin composition for a reflective plate contains a polyamide resin (A), inorganic fibers (B), a colorant (C), and a polycarboxylic acid (D).

Description

Technical Field

[0001] The present invention relates to a polyamide resin composition for a reflective plate containing a polyamide resin and a reflective plate obtained by molding the polyamide resin composition for a reflective plate. Background Art

[0002] Light-emitting devices using light-emitting diodes (hereinafter referred to as "LEDs") are small and lightweight, easy to assemble into various instruments, and have a very long life due to their strong resistance to vibration and repeated ON / OFF. In addition, light-emitting devices using LEDs (hereinafter referred to as LED light-emitting devices) have various preferred characteristics such as bright colors, excellent visibility, and relatively low power consumption. Among them, white LED light-emitting devices that combine blue LEDs and phosphors have become practical, and have attracted much attention as light sources for backlights of liquid crystal display screens of mobile phones, computers, televisions, etc., headlights of cars, dashboards, or lighting fixtures.

[0003] An LED light emitting device is generally mainly composed of an LED as a light emitting portion, a reflection plate (reflector) also serving as a housing, a transparent sealant for sealing and protecting the LED, and lead wires.

[0004] Considering the strength of light resistance and heat resistance, silicone resin is usually used as the sealant of LED. In this case, the reflector of the LED light-emitting device requires high adhesion with the silicone resin. As a resin composition for a reflector having high adhesion with the silicone resin, the following patent document 1 discloses a resin composition comprising a polyamide resin, titanium oxide, inorganic fiber and a silanol condensate. It is recorded that the reflector obtained by the resin composition of patent document 1 has high adhesion with the silicone resin constituting the sealant.

[0005] In addition, when using LED sealants outdoors, moisture may cause the light not to light up, so epoxy resins with higher gas barrier properties than silicone resins are sometimes used as sealants. Therefore, the reflector of outdoor LED light-emitting devices requires high adhesion with epoxy resins.

[0006] Therefore, Patent Document 2 below discloses a resin composition containing a polyamide resin, an inorganic filler, a white pigment, and an epoxy resin as a resin composition for a reflective plate capable of improving adhesion with an epoxy resin used as a sealant when used outdoors.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2013-091737

[0010] Patent Document 2: Japanese Patent Application Publication No. 2007-271834 Summary of the invention

[0011] Technical problem to be solved by the invention

[0012] In recent years, in light-emitting devices such as LEDs, it is required to further improve the adhesion between the reflector and the sealant. In particular, even when exposed for a long time under harsh conditions such as outdoor use, it is required that the reflector and the sealant are stable and have high adhesion. However, in the reflector obtained using the resin composition of Patent Document 2, there is also a problem that the adhesion with the sealant cannot be fully improved.

[0013] The present invention aims to solve the above problems and to provide a polyamide resin composition for a reflecting plate, which can provide a reflecting plate having excellent adhesion to a sealant used in a light-emitting device such as an LED, and a reflecting plate obtained by molding the polyamide resin composition for a reflecting plate.

[0014] Technical solutions for solving technical problems

[0015] The present invention provides a polyamide resin composition for a reflecting plate having the following constitution, and a reflecting plate obtained by molding the resin composition for a reflecting plate.

[0016] Item 1 A polyamide resin composition for a reflective plate, comprising: a polyamide resin (A), an inorganic fiber (B), a colorant (C) and a polycarboxylic acid (D).

[0017] Item 2: The polyamide resin composition for a reflecting plate according to Item 1, wherein the melting point of the polycarboxylic acid (D) is 150°C to 300°C.

[0018] Item 3: The polyamide resin composition for a reflecting plate according to Item 1 or Item 2, wherein the polycarboxylic acid (D) is an aromatic polycarboxylic acid compound.

[0019] Item 4 The polyamide resin composition for a reflecting plate according to any one of Items 1 to 3, wherein the polycarboxylic acid (D) is one or more selected from aromatic dicarboxylic acids, aromatic tricarboxylic acids, and anhydrides thereof.

[0020] Item 5 The polyamide resin composition for a reflecting plate according to any one of Items 1 to 4, wherein the polycarboxylic acid (D) is one or more selected from phthalic acid, trimellitic acid, and anhydrides thereof.

[0021] Item 6 The polyamide resin composition for a reflecting plate according to any one of Items 1 to 5, wherein the polyamide resin (A) has a melting point of 280° C. or higher.

[0022] Item 7 The polyamide resin composition for a reflecting plate according to any one of Items 1 to 6, wherein the proportion of the structural unit derived from an aromatic monomer in all the structural units constituting the polyamide resin (A) is 20 mol% or more.

[0023] Item 8 The polyamide resin composition for a reflecting plate according to any one of Items 1 to 7, wherein the polyamide resin (A) is a semi-aromatic polyamide resin containing an aromatic dicarboxylic acid and an aliphatic alkylenediamine as structural units.

[0024] Item 9 The polyamide resin composition for a reflecting plate according to any one of Items 1 to 8, wherein the inorganic fiber (B) is one or more selected from wollastonite fiber and potassium titanate fiber.

[0025] Item 10. A reflective plate, which is a molded product of the polyamide resin composition for a reflective plate according to any one of Items 1 to 9.

[0026] Item 11 is a reflective plate as described in Item 10, wherein the reflective plate is used for LEDs.

[0027] Effects of the Invention

[0028] According to the present invention, there are provided a polyamide resin composition for a reflecting plate, which can provide a reflecting plate having excellent adhesion to a sealant used in a light-emitting device such as an LED, and a reflecting plate obtained by molding the polyamide resin composition for a reflecting plate. DETAILED DESCRIPTION

[0029] The polyamide resin composition for a reflective plate of the present invention is a resin composition comprising a polyamide resin (A), an inorganic fiber (B), a colorant (C) and a polycarboxylic acid (D).

[0030] The polyamide resin composition for reflector of the present invention comprises polyamide resin (A), inorganic fiber (B), colorant (C) and polycarboxylic acid (D), and can obtain a reflector having excellent adhesion to a sealant used for a light-emitting device such as an LED. In particular, even when exposed for a long time under harsh conditions such as outdoor use, a reflector having excellent adhesion to a sealant can be obtained. In addition, the polyamide resin composition for reflector of the present invention can be colored in various colors, and the mechanical strength and heat resistance of the molded product, especially the adhesion to the epoxy sealant of the LED, can be improved at a high level.

[0031] In the present invention, the melting point of the polycarboxylic acid (D) is preferably 150° C. to 300° C. The polycarboxylic acid (D) is more preferably an aromatic polycarboxylic acid compound.

[0032] In the present invention, the melting point of the polyamide resin (A) is preferably 280° C. or higher.

[0033] In the present invention, the ratio of the structural unit derived from the aromatic monomer in all structural units constituting the polyamide resin (A) is preferably 20 mol% or more. The polyamide resin (A) is preferably a semi-aromatic polyamide resin containing an aromatic dicarboxylic acid and an aliphatic alkylene diamine as structural units.

[0034] In the present invention, the inorganic fiber (B) is preferably one or more selected from wollastonite fiber and potassium titanate fiber, and more preferably wollastonite fiber.

[0035] When using such a polyamide resin (A), inorganic fiber (B), colorant (C) and polycarboxylic acid (D) to constitute a polyamide resin composition for a reflector, it can be easily colored in various colors, and the mechanical strength, heat resistance and adhesion of the reflector to the sealant used for light-emitting devices such as LEDs can be improved to a higher level.

[0036] The reflective plate of the present invention is a molded product of the polyamide resin composition for a reflective plate. The reflective plate of the present invention can be suitably used for LED (light emitting diode) applications.

[0037] Hereinafter, each constituent element of the polyamide resin composition for a reflecting plate of the present invention will be described.

[0038] <Polyamide resin composition for reflective plate>

[0039] The polyamide resin composition for a reflective plate of the present invention comprises a polyamide resin (A), inorganic fibers (B), a colorant (C) and a polycarboxylic acid (D), and may contain other additives as necessary.

[0040] (Polyamide resin (A))

[0041] As the polyamide resin (A) used in the present invention, various aliphatic monomers and / or aromatic monomers can be used as monomer components, and any polyamide resin can be used without particular limitation. The polyamide resin (A) used in the present invention preferably has a melting point of 280°C or more in order to suppress deformation and discoloration of the reflector during reflow soldering. In addition, in order to suppress thermal decomposition of the polyamide resin (A) during melt processing such as melt kneading and injection molding, the melting point is preferably 350°C or less, and more preferably 330°C or less. The melting point can be measured according to JIS-K7121.

[0042] The polyamide resin (A) used in the present invention is preferably a semi-aromatic polyamide resin in order to suppress deformation or deterioration of physical properties due to moisture absorption, and is preferably a semi-aromatic polyamide resin containing an aromatic dicarboxylic acid and an aliphatic alkylene diamine.

[0043] The polyamide resin (A) used in the present invention is a polymer having an amide bond (-NH-C(=O)-) in the main chain, and is a polymer containing structural units derived from monomer components such as aliphatic monomers and aromatic monomers described later. The semi-aromatic polyamide resin may be composed of one structural unit or a plurality of structural units. As the case where it is composed of one structural unit, a polymer of aminocarboxylic acid can be cited. As the case where it is composed of a plurality of structural units, copolymers of diamines and dibasic acids; copolymers of diamines, dibasic acids and aminocarboxylic acids, etc. can be cited. In the case of a copolymer composed of a plurality of structural units, the copolymerization ratio, the copolymerization form such as a random copolymer, a block copolymer, an alternating copolymer, etc. can be arbitrarily selected.

[0044] In the polyamide resin (A) used in the present invention, the proportion of the structural unit derived from the aromatic monomer in all structural units constituting the polyamide resin (A) is preferably 20 mol% or more, more preferably 25 mol% or more, and further preferably 25 to 60 mol%.

[0045] The polyamide resin (A) is preferably a semi-aromatic polyamide resin containing, as structural units, a structural unit derived from an aromatic dicarboxylic acid and a structural unit derived from an aliphatic diamine, and more preferably a semi-aromatic polyamide resin containing, as structural units, a structural unit derived from an aromatic dicarboxylic acid, a structural unit derived from an aliphatic dicarboxylic acid, and a structural unit derived from an aliphatic diamine. The molar fraction of the structural unit derived from an aromatic monomer in the polyamide resin (A) refers to the molar fraction of the aromatic monomer in all monomers used in the polymerization raw material.

[0046] Physical properties such as the melting point can be appropriately adjusted by appropriately selecting the composition ratio and types of the aromatic monomer and other monomer components constituting the polyamide resin (A).

[0047] Examples of the structural unit derived from an aliphatic monomer include aliphatic dicarboxylic acids, aliphatic diamines, aliphatic aminocarboxylic acids, alicyclic dicarboxylic acids, alicyclic diamines, and alicyclic aminocarboxylic acids.

[0048] Examples of the aliphatic dicarboxylic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonane diacid, 1,10-decanedioic acid, and 1,11-undecanedioic acid. Among these, adipic acid is preferred as the aliphatic dicarboxylic acid. These may be used alone or in combination of two or more.

[0049] As the aliphatic diamine, for example, aliphatic alkylenediamines can be cited. Specifically, as the aliphatic diamine, ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 2-methyl-1,5-diaminopentane, 3-methyl-1,5-diaminopentane, 2-ethyltetramethylenediamine, etc. can be cited. Among these, as the aliphatic diamine, hexamethylenediamine, 1,9-diaminononane, 1,10-diaminodecane and 2-methylpentamethylenediamine are also preferred. They can be used alone or in combination of two or more.

[0050] As aliphatic aminocarboxylic acids, for example, 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, etc. can be listed. In addition, lactams corresponding to these can also be used. They can be used alone or in combination of two or more.

[0051] Examples of the alicyclic dicarboxylic acid include 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. Among these, 1,4-cyclohexanedicarboxylic acid is preferred as the alicyclic dicarboxylic acid. These may be used alone or in combination of two or more.

[0052] Examples of the alicyclic diamine include 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,2-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, isophoronediamine, piperazine, etc. These may be used alone or in combination of two or more.

[0053] Examples of the alicyclic aminocarboxylic acid include aminocycloalkanecarboxylic acids, specifically, aminocyclopropanecarboxylic acids such as 2-aminomethylcyclopropanecarboxylic acid, and aminocyclohexanecarboxylic acids such as 4-aminocyclohexanecarboxylic acid, 3-aminocyclohexanecarboxylic acid, 4-(aminomethyl)cyclohexanecarboxylic acid, and 3-(aminomethyl)cyclohexanecarboxylic acid. These may be used alone or in combination of two or more.

[0054] Examples of the structural unit derived from an aromatic monomer include aromatic dicarboxylic acids, aromatic diamines, and aromatic aminocarboxylic acids.

[0055] Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 2-methylterephthalic acid, and naphthalene dicarboxylic acid. Among these, terephthalic acid and isophthalic acid are also preferred aromatic dicarboxylic acids, and terephthalic acid is more preferred. These may be used alone or in combination of two or more.

[0056] Examples of the aromatic diamine include p-phenylenediamine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, and m-phenylenediamine. These may be used alone or in combination of two or more.

[0057] Examples of the aromatic aminocarboxylic acid include p-aminobenzoic acid, p-aminomethylbenzoic acid, etc. These may be used alone or in combination of two or more.

[0058] Specific examples of the polyamide resin (A) include polyamide MXD6, polyamide 6T, polyamide 9T, polyamide 10T, and the like.

[0059] In the present invention, the content of the polyamide resin (A) is preferably 30% to 98.9% by mass, more preferably 40% to 70% by mass, further preferably 45% to 65% by mass, further preferably 50% to 65% by mass, and particularly preferably 55% to 60% by mass, relative to 100% by mass of the total amount of the polyamide resin composition for a reflector.

[0060] By setting the content of the polyamide resin (A) in the above range, a resin composition having relatively excellent heat resistance can be obtained while suppressing a decrease in mechanical strength without impairing moldability.

[0061] (Inorganic fiber (B))

[0062] As the inorganic fiber (B) used in the present invention, for example, glass fiber, milled glass fiber, carbon fiber, milled carbon fiber, zinc oxide fiber, sodium titanate fiber, potassium titanate fiber, aluminum borate fiber, magnesium borate fiber, magnesium oxide fiber, aluminum silicate fiber, silicon nitride fiber, wollastonite fiber, etc. can be cited. As the inorganic fiber (B), one or more selected from the above-mentioned inorganic fibers can be used, which can improve the mechanical strength, dimensional stability and heat resistance of the obtained resin composition. As the inorganic fiber (B) used in the present invention, from the viewpoint of improving hiding power, and from the viewpoint of plane smoothness and microscopic enhancement, it is preferred to use one or more selected from wollastonite fiber and potassium titanate fiber, and from the viewpoint of whiteness, wollastonite fiber is more preferably used.

[0063] Wollastonite fiber is an inorganic fiber composed of calcium metasilicate. The size of wollastonite fiber is not particularly limited, and the average fiber length is preferably 5μm to 180μm, more preferably 10μm to 100μm, further preferably 20μm to 40μm, and particularly preferably 20μm to 30μm. The average fiber diameter of wollastonite fiber is preferably 0.1μm to 15μm, more preferably 1μm to 10μm, further preferably 2μm to 7μm, and particularly preferably 2μm to 5μm. The average aspect ratio of wollastonite fiber is preferably 3 or more, more preferably 3 to 30, further preferably 3 to 15, further preferably 3 to 10, and particularly preferably 3 to 8.5.

[0064] These wollastonite fibers may be commercially available products, and for example, "Baistal W" (average fiber length 25 μm, average fiber diameter 3 μm) manufactured by Otsuka Chemical Co., Ltd. may be used.

[0065] As potassium titanate fibers, existing well-known potassium titanate fibers can be widely used, and examples thereof include potassium tetratitanate fibers, potassium hexatitanate fibers, potassium octatitanate fibers, and the like. The size of the potassium titanate fibers is not particularly limited, and the average fiber length is preferably 1 μm to 50 μm, more preferably 3 μm to 30 μm, and further preferably 3 μm to 20 μm. The average fiber diameter of the potassium titanate fibers is preferably 0.01 μm to 1 μm, more preferably 0.05 μm to 0.8 μm, and further preferably 0.1 μm to 0.7 μm. The average aspect ratio of the potassium titanate fibers is preferably greater than 10, more preferably 10 to 100, and further preferably 15 to 35.

[0066] These potassium titanate fibers may be commercially available products, for example, "TISMOD" (average fiber length 15 μm, average fiber diameter 0.5 μm) and "TISMON" (average fiber length 15 μm, average fiber diameter 0.5 μm) manufactured by Otsuka Chemical Co., Ltd. may be used.

[0067] In the present specification, the average fiber length and average fiber diameter of the inorganic fibers (B) can be measured by observation with a scanning electron microscope, and the average aspect ratio (average fiber length / average fiber diameter) of the inorganic fibers (B) can be calculated from the average fiber length and the average fiber diameter.

[0068] For example, a plurality of inorganic fibers (B) are photographed using a scanning electron microscope, and 300 inorganic fibers (B) are randomly selected from the observation image to measure their fiber lengths and fiber diameters. The value obtained by accumulating all fiber lengths and dividing the value by the number of fibers can be used as the average fiber length, and the value obtained by accumulating all fiber diameters and dividing the value by the number of fibers can be used as the average fiber diameter.

[0069] In the present invention, in order to further improve the physical properties of the obtained resin composition, such as mechanical strength, the inorganic fibers (B) may be subjected to a surface treatment.

[0070] The inorganic fiber (B) is preferably an inorganic fiber having at least a portion of its surface covered by a treatment layer composed of a surface treatment agent. In addition, the treatment layer preferably covers more than 50% of the surface of the inorganic fiber, more preferably more than 80%. In particular, it is preferred that the treatment layer covers the entire surface of the inorganic fiber.

[0071] In addition, the inorganic fibers (B) may be a mixture of inorganic fibers at least part of whose surface is covered with a treatment layer composed of a surface treatment agent and untreated inorganic fibers whose surface is not covered with a surface treatment agent, within a range not impairing the preferred physical properties.

[0072] The surface treatment agent is preferably a hydrophobic surface treatment agent.

[0073] As the hydrophobic surface treatment agent, for example, silane coupling agent, titanium coupling agent, aluminate coupling agent, etc. can be cited. Among these, as the hydrophobic surface treatment agent, silane coupling agent is also preferably used. As the silane coupling agent, amino silane coupling agent, epoxy silane coupling agent, alkyl silane coupling agent, preferably amino silane coupling agent (aminosilane) is used. The above-mentioned hydrophobic surface treatment agent can be used alone or in combination of two or more.

[0074] Examples of the amino-based silane coupling agent include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and 3-(N-vinylbenzyl-2-aminoethyl)aminopropyltrimethoxysilane.

[0075] Examples of the epoxy silane coupling agent include 3-glycidyloxypropyl(dimethoxy)methylsilane, 3-glycidyloxypropyltrimethoxysilane, diethoxy(3-glycidyloxypropyl)methylsilane, triethoxy(3-glycidyloxypropyl)silane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0076] Examples of the alkyl silane coupling agent include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, and n-decyltrimethoxysilane.

[0077] In the present invention, as a surface treatment method for inorganic fibers (B), as a method for pre-treating the surface of inorganic fibers (B) with a surface treatment agent, a dry method and a wet method are known, and either method can be used. At this time, the surface treatment concentration is appropriately about 0.1% to 3.0% by mass relative to 100% by mass of the inorganic fibers (B).

[0078] As a method for forming a treatment layer containing a surface treatment agent on the surface of the inorganic fiber (B), a known surface treatment method can be used, for example, the following dry method is used: a reinforcing material is added to a device capable of high-speed stirring such as a Henschel mixer, and under stirring, the reinforcing material is sprayed with a surface treatment agent (in the case of a liquid) or a solution obtained by dissolving the surface treatment agent in a solvent that promotes hydrolysis (such as water, alcohol or a mixed solvent thereof).

[0079] The amount of the surface treatment agent used to treat the surface of the inorganic fiber (B) used in the present invention is not particularly limited. In the case of a dry method, for example, a solution of the surface treatment agent can be sprayed in an amount of 0.1 to 20 parts by mass relative to 100 parts by mass of the inorganic fiber (B).

[0080] By setting the amount of the surface treatment agent within the above range, the adhesion between the polyamide resin (A) and the polycarboxylic acid (D) is further improved, and the dispersibility of the inorganic fibers (B) can be further improved.

[0081] The content of the inorganic fiber (B) in the polyamide resin composition for a reflective plate of the present invention is preferably 0.5% to 50% by mass, more preferably 5% to 48% by mass, even more preferably 10% to 45% by mass, and particularly preferably 15% to 45% by mass, relative to 100% by mass of the total amount of the polyamide resin composition for a reflective plate.

[0082] By setting the content of the inorganic fibers (B) to be within the above range, heat resistance and mechanical strength can be further improved.

[0083] (Colorant (C))

[0084] The colorant (C) used in the present invention can be appropriately selected according to its purpose, for example, pigments such as organic pigments or inorganic pigments, dyes such as organic dyes, etc. can be used. The above-mentioned colorant (C) can be used in multiple forms in order to adjust the chromaticity, etc., and one or more pigments and dyes can also be used. Specific examples of usable colorants (C) include: organic pigments such as azo pigments, anthraquinone pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, diketopyrrolopyrrole pigments, dioxazine pigments, etc.; black pigments such as carbon black, titanium black, cobalt black, white pigments such as titanium oxide, ultramarine, cobalt blue, red iron oxide, etc.; body pigments such as calcium carbonate and barium sulfate; organic dyes such as azo dyes, anthraquinone dyes, and perylene dyes. In addition, pigments and dyes can also be used together. In this case, various oil-soluble dyes, disperse dyes, etc., or products obtained by processing pigments with higher fatty acids, synthetic resins, etc. can be listed.

[0085] The colorant (C) used in the present invention is preferably a white pigment, more preferably titanium oxide, from the viewpoint of further improving the whiteness of the reflector. The colorant (C) is preferably a black pigment, more preferably carbon black, from the viewpoint of further reducing the reflection of light from external light. In addition, as the colorant (C), a white pigment and a black pigment can be used in combination.

[0086] As the titanium oxide, various crystalline forms of titanium oxide such as anatase, rutile, and monoclinic can be used. Among them, the titanium oxide preferably has a high refractive index and good light stability of rutile. The titanium oxide can be treated with a known surface treatment agent such as aluminum oxide, silicon dioxide, a silane coupling agent, and a titanium coupling agent as needed. In addition, the titanium oxide can be used in various shapes of powders such as granular, fibrous, and plate-like (including flake, flaky, mica, etc.), and granular powders can be preferably used.

[0087] The size of the white pigment used in the present invention is not particularly limited. From the viewpoint of improving whiteness, the average particle size may be preferably 0.05 μm to 0.5 μm, and more preferably 0.1 μm to 0.3 μm. The average particle size of the white pigment may be measured by laser diffraction. As the white pigment used in the present invention, one or more of the above-mentioned white pigments may be used.

[0088] On the other hand, the size of the black pigment used in the present invention is not particularly limited, but from the viewpoint of further reducing the reflection of light from external light, the average particle size is preferably 1 nm to 100 nm, more preferably 5 nm to 80 nm, and further preferably 10 nm to 60 nm.

[0089] The content of the colorant (C) in the polyamide resin composition for a reflective plate of the present invention is preferably 0.5% by mass to 40% by mass based on 100% by mass of the total amount of the resin composition.

[0090] When black pigment is used, its content is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, further preferably 0.7% by mass or more, preferably 5% by mass or less, more preferably 4.5% by mass or less, further preferably 3% by mass or less relative to the total amount 100% by mass of the polyamide resin composition for the reflector. If the content of the black pigment is within the above range, a resin composition having good moldability and appearance and excellent mechanical strength can be obtained.

[0091] When white pigment is used, its content is preferably 1% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, further preferably 25% by mass or less relative to the total amount 100% by mass of the polyamide resin composition for reflector. If the content of white pigment is within the above range, a resin composition having good moldability and appearance and excellent mechanical strength can be obtained.

[0092] (Polycarboxylic acid (D))

[0093] The polycarboxylic acid (D) used in the present invention can be used without particular limitation as long as it is a polycarboxylic acid and its equivalent and a compound having two or more carboxyl groups in one molecule. The polycarboxylic acid (D) may be an anhydride of a compound having two or more carboxyl groups in one molecule. The number of carboxyl groups contained in one molecule is preferably 2 to 4, particularly preferably 3. In addition, the polycarboxylic acid (D) is preferably one or more selected from aliphatic polycarboxylic acid compounds, alicyclic polycarboxylic acid compounds and aromatic polycarboxylic acid compounds, more preferably an aromatic polycarboxylic acid compound.

[0094] Specific examples of aliphatic polycarboxylic acid compounds include adipic acid, 1,6-adipic acid, 1,7-pimelic acid, 1,8-octanedioic acid, 1,9-zelaic acid, 1,10-decanedioic acid, 1,11-undecanedioic acid, 1,12-dodecanediol, etc. These can be used alone or in combination of two or more. Among the above-mentioned aliphatic polycarboxylic acid compounds, aliphatic polycarboxylic acid compounds having 6 to 20 carbon atoms are also preferred.

[0095] Specific examples of alicyclic polycarboxylic acid compounds include hexahydrophthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, cyclopentanetetracarboxylic acid, etc. These can be used alone or in combination of two or more. Among the above-mentioned alicyclic polycarboxylic acid compounds, alicyclic polycarboxylic acid compounds having 8 to 20 carbon atoms are also preferred.

[0096] As the aromatic polycarboxylic acid compound, any aromatic compound and its anhydride having two or more carboxyl groups can be used without particular limitation. The aromatic compound can be any compound showing aromaticity, and examples thereof include benzene-based aromatic compounds having an aromatic ring formed by condensation or connection of one or more benzene rings in the structure, and non-benzene-based aromatic compounds showing aromaticity without a benzene ring. Among them, benzene-based aromatic compounds are preferably used, and from the viewpoint of increasing the carboxyl content per unit molecular mass, the number of aromatic rings formed by condensation or connection of benzene rings is a polycarboxylic acid compound having usually 1 to 3, preferably 1 benzene ring.

[0097] Specific examples of the aromatic polycarboxylic acid compound include: aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, 2,6-naphthalene dicarboxylic acid and other naphthalene dicarboxylic acids as their positional isomers, 1,1'-biphenyl-4,4'-dicarboxylic acid and other biphenyl dicarboxylic acids as their positional isomers, 2,6-anthracene dicarboxylic acid and other anthracene dicarboxylic acids as their positional isomers; aromatic tricarboxylic acids such as trimellitic acid, trimesic acid, trimesic acid, 2,3,6-naphthalene tricarboxylic acid and other naphthalene tricarboxylic acids as their positional isomers, 2,3,6-anthracene tricarboxylic acid and other anthracene tricarboxylic acids as their positional isomers; and aromatic tricarboxylic acids such as mellophane tetracarboxylic acid, prehnitic acid, pyromellitic acid. Aromatic tetracarboxylic acids such as 1,4,5,8-naphthalenetetracarboxylic acid and other naphthalenetetracarboxylic acids as positional isomers thereof, 2,3,6,7-anthracenetetracarboxylic acid and other anthracenetetracarboxylic acids as positional isomers thereof, or their anhydrides. These may be used alone or in combination of two or more.

[0098] Among the above-mentioned aromatic polycarboxylic acid compounds, one or more selected from aromatic dicarboxylic acids having 8 to 20 carbon atoms, aromatic tricarboxylic acids having 8 to 20 carbon atoms, and their anhydrides are also preferred, one or more selected from aromatic dicarboxylic acids having 8 to 14 carbon atoms, aromatic tricarboxylic acids having 8 to 14 carbon atoms, and their anhydrides are more preferred, one or more selected from phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and their anhydrides are further preferred, phthalic acid, trimellitic acid, or trimellitic anhydride is particularly preferred, and trimellitic acid or trimellitic anhydride is most preferred.

[0099] The melting point of the polycarboxylic acid (D) is preferably 150°C to 300°C, more preferably 150°C to 250°C, from the viewpoint of processability.

[0100] The content of the polycarboxylic acid (D) in the polyamide resin composition for reflective plates of the present invention is preferably 0.1% to 2% by mass, more preferably 0.1% to 1% by mass, further preferably 0.2% to 0.8% by mass, and particularly preferably 0.3% to 0.7% by mass, relative to 100% by mass of the total amount of the resin composition. By making the content of the polycarboxylic acid (D) within this range, the adhesion between the polyamide resin composition and the epoxy sealant can be further improved while maintaining the mechanical strength.

[0101] (Other additives)

[0102] The polyamide resin composition for reflective plate of the present invention may contain additives such as inorganic fillers, antioxidants, heat stabilizers, flame retardants, plasticizers, nucleating agents, release agents, ultraviolet absorbers, etc. within the range that does not impair its preferred physical properties. These additives may be used alone or in combination of two or more.

[0103] Examples of the inorganic filler include talc, silica, zinc oxide (including tetrapod-shaped zinc oxide), mica, and barium sulfate.

[0104] Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, and sulfur antioxidants.

[0105] Examples of the phenolic antioxidant include triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,5-di-tert-butyl-4 -Hydroxybenzylphosphonic acid diethyl ester, N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamic acid amide), 1,3,5-trimethyl-2,4,6-tri(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, etc.

[0106] Among these, as the phenolic antioxidant, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and N,N′-hexamethylenebis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionamide are preferred.

[0107] Examples of the phosphorus antioxidant include tris(2,4-di-tert-butylphenyl)phosphite, 2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1.3.2]dioxaphosphepin-6-yl]oxy]-N,N-bis[2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1.3.2]dioxaphosphepin-6-yl]oxy]-ethyl]ethylamine, and bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite. Among these, as a phosphorus-based antioxidant, 2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1.3.2]dioxaphosphapin-6-yl]oxy]-N,N-bis[2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1.3.2]dioxaphosphapin-6-yl]oxy]-ethyl]ethylamine is also preferred.

[0108] Examples of the sulfur-based antioxidant include 2,2-thio-diethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tetrakis[methylene-3-(dodecylthio)propionate]methane.

[0109] The amount of additives other than the essential components that can be used in the present invention is not particularly limited as long as it does not damage the preferred physical properties of the resin composition of the present invention. The amount of additives other than the essential components is usually 10% by mass or less, preferably 7% by mass or less, and more preferably 5% by mass or less relative to 100% by mass of the total amount of the resin composition.

[0110] <Method for producing polyamide resin composition for reflective plate and reflective plate>

[0111] The polyamide resin composition for reflective plate of the present invention can be produced by mixing and heating (particularly melt kneading) a mixture containing polyamide resin, inorganic fiber, colorant and polycarboxylic acid in various proportions and other additives as required. For melt kneading, a known melt kneading device such as a twin-screw extruder can be used.

[0112] The heating temperature of melt-kneading is not particularly limited as long as it is a temperature at which the polyamide resin can melt, and can usually be set to a temperature above the melting point of the polyamide resin and below the decomposition start temperature. Usually, the temperature in the barrel of the melt-kneading device used in melt-kneading is adjusted to this temperature range. In this way, the polyamide resin composition for reflector of the present invention that can exert the desired effect can be manufactured.

[0113] Furthermore, the polyamide resin composition for a reflecting plate of the present invention can provide a reflecting plate having excellent adhesion to a sealant used for a light-emitting device such as an LED, and can improve the adhesion to an epoxy sealant.

[0114] The resin composition of the present invention can be made into various molded products according to the type, application, shape, etc. of the target molded product by known resin molding methods such as injection molding, insert molding, compression molding, extrusion molding, blow molding, and inflation molding. In addition, a molding method combining the above molding methods can also be used.

[0115] The reflector obtained by molding the resin composition of the present invention has excellent adhesion with the epoxy resin as a sealant, so it can be suitable for LED reflectors, preferably LED reflectors for outdoor use, and it also has excellent discoloration resistance, so it can be used as an LED reflector without plating the light reflecting surface.

[0116] As mentioned above, the reflector of the present invention refers to a reflector (reflector) for a light emitting device. It should be noted that, although it is recorded as a reflective "plate", its shape is not particularly limited as long as it has the performance of reflecting light, and is not limited to a "plate"-like plane shape. For example, it also includes three-dimensional shapes such as box-shaped, cone-shaped, and parabolic.

[0117] The reflector of the present invention can be used not only in LED light-emitting devices, but also in other applications for reflecting light, such as various electrical and electronic components, keyless entry systems for automobiles, lighting in cold storages, backlights for liquid crystal display devices, front panel lighting devices for automobiles, lighting table lamps, bedside lamps, indicator lights for home appliances, optical communication devices such as infrared communication, and ceiling lighting devices.

[0118] Example

[0119] The following is specifically described based on the embodiments and comparative examples, but the present invention is not limited by them. It should be noted that the polyamide resin, epoxy resin, inorganic fiber, colorant, and polycarboxylic acid used in the present embodiment and comparative example are specifically as follows. In addition, the melting point of the polyamide resin is an endothermic peak obtained by heating from 25 ° C to 10 ° C / minute under a nitrogen flow using a differential scanning calorimeter (Seiko Instruments, trade name "DSC6200"). The melting point of the polycarboxylic acid is measured using an automatic melting point measuring device (Mettler Toledo, Melting Point System MP70) in accordance with the light transmission method of JIS K 0064.

[0120] <Polyamide resin>

[0121] Polyamide resin: a semi-aromatic polyamide resin prepared by polymerizing hexamethylenediamine, terephthalic acid, and adipic acid at a ratio of 50 mol %, 27.5 mol %, and 22.5 mol %, respectively; manufactured by DuPont, trade name “Zytel HTN502HF”, melting point 310°C.

[0122] <Epoxy resin>

[0123] Epoxy resin 1: melting point 107° C., manufactured by Mitsubishi Chemical Corporation, trade name “JER YX4000HK”.

[0124] Epoxy resin 2: softening point 76° C., manufactured by Daicel Corporation, trade name “EHPE3150”.

[0125] <Inorganic Fiber>

[0126] Wollastonite fiber: average fiber length 25 μm, average fiber diameter 3 μm, manufactured by Otsuka Chemical Co., Ltd., trade name “Baistal W”.

[0127] <Coloring agent>

[0128] Carbon masterbatch: carbon black (50% by mass) and polyamide MXD6 (50% by mass), manufactured by Ohta Chemical Co., Ltd., trade name “NB-35 Grain black”.

[0129] Titanium oxide: average particle size 0.21 μm, manufactured by Tayca, trade name “JR-405”.

[0130] <Polycarboxylic acid>

[0131] Polycarboxylic acid 1: trimellitic acid, melting point 231°C.

[0132] Polycarboxylic acid 2: trimellitic anhydride, melting point 168°C.

[0133] Polycarboxylic acid 3: phthalic acid, melting point 210°C.

[0134] <Examples 1 to 4 and Comparative Examples 1 to 4>

[0135] In Examples 1 to 4 and Comparative Examples 1 to 4, each material was melt-kneaded using a twin-screw extruder at the blending ratio shown in Table 1 to produce pellets. The barrel temperature of the twin-screw extruder was 320°C.

[0136] The obtained pellets were used to form JIS test pieces and flat plates of 30 mm in length×30 mm in width×3 mm in thickness by an injection molding machine to prepare evaluation samples. The cylinder temperature of the injection molding machine was 320°C and the mold temperature was 150°C.

[0137] <Evaluation>

[0138] The following evaluations were performed using the evaluation samples obtained in Examples 1 to 4 and Comparative Examples 1 to 4.

[0139] (1) Initial adhesion

[0140] After curing the epoxy sealant (manufactured by Inabata Industry Co., Ltd., trade name "IK0010") on the surface of the obtained flat plate at 165°C for 1 hour, the post-curing was performed at 150°C for 4 hours to prepare a 4 mm × 4 mm × 1 mm high protrusion as a close adhesion test piece. The force required to peel the protrusion of the obtained close adhesion test piece from the flat plate was measured as the initial close adhesion. The results are shown in Table 1.

[0141] (2) Sealing strength after water absorption test

[0142] The adhesion test piece prepared in the above steps was placed in a constant temperature and humidity chamber at 85°C x 85% HR for one week, and the force required to peel the protrusions from the plate was measured in the same manner as above to obtain adhesion after the water absorption test.

[0143] (3) Hunter whiteness

[0144] The Hunter whiteness (W1) of the obtained flat plate immediately after molding was measured using a colorimeter (manufactured by Nippon Denshoku Co., Ltd., trade name “ZE6000”). The results are shown in Table 1.

[0145] [Table 1]

[0146]

[0147] As can be seen from Table 1, Examples 1 to 4 to which polycarboxylic acids are added have improved initial adhesion and adhesion after the water absorption test compared to Comparative Examples 1 to 4 to which no polycarboxylic acids are added. On the other hand, the initial adhesion of Comparative Examples 2 and 3 to which epoxy resins are added slightly decreases, but the adhesion improves after the water absorption test. Therefore, even with epoxy resins, improvements in actual outdoor use can be expected. However, the polycarboxylic acid addition system of Examples 1 to 4 has a dramatic improvement in adhesion at the initial stage and after the water absorption test compared to the epoxy resin addition system. It can be seen from this that by adding polycarboxylic acids, a significant technical effect of improving adhesion can be exerted that is greater than that of the epoxy resin addition system.

Claims

1. A polyamide resin composition for a reflective plate, characterized in that: The invention comprises a polyamide resin (A), an inorganic fiber (B), a colorant (C) and a polycarboxylic acid (D).

2. The polyamide resin composition for a reflective plate according to claim 1, wherein: The melting point of the polycarboxylic acid (D) is 150°C to 300°C.

3. The polyamide resin composition for a reflector according to claim 1 or claim 2, wherein: The polycarboxylic acid (D) is an aromatic polycarboxylic acid compound.

4. The polyamide resin composition for a reflective plate according to claim 1 or claim 2, wherein: The polycarboxylic acid (D) is one or more selected from aromatic dicarboxylic acids, aromatic tricarboxylic acids and anhydrides thereof.

5. The polyamide resin composition for a reflective plate according to claim 1 or claim 2, wherein: The polycarboxylic acid (D) is one or more selected from phthalic acid, trimellitic acid and anhydrides thereof.

6. The polyamide resin composition for a reflective plate according to claim 1 or claim 2, wherein: The melting point of the polyamide resin (A) is 280° C. or higher.

7. The polyamide resin composition for a reflective plate according to claim 1 or claim 2, wherein: The proportion of the structural unit derived from the aromatic monomer in all the structural units constituting the polyamide resin (A) is 20 mol% or more.

8. The polyamide resin composition for a reflective plate according to claim 1 or claim 2, wherein: The polyamide resin (A) is a semi-aromatic polyamide resin containing an aromatic dicarboxylic acid and an aliphatic alkylene diamine as structural units.

9. The polyamide resin composition for a reflective plate according to claim 1 or claim 2, wherein: The inorganic fibers (B) are one or more selected from wollastonite fibers and potassium titanate fibers.

10. A reflector, characterized in that: This is a molded body of the polyamide resin composition for a reflecting plate according to claim 1 or claim 2.

11. The reflector according to claim 10, wherein: The reflective plate is used for LEDs.

Images