JP2007269890A - Laser welding resin composition and molded product using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition having a metallic tone bright appearance and the permeability required for laser welding, and generating high laser welding strength, and to provide a molded product using it. <P>SOLUTION: This laser welding resin composition comprises (A) 100 pts.wt. of a thermoplastic resin such as (A1) a polyamide resin, (A2) a polybutylene terephthalate resin or (A3) a polyphenylene sulfide resin, and (B) 0.5-2 pts.wt. of a luster pigment having a metal oxide layer. The molded product obtained by using the resin composition and a molded object obtained using a laser welding technique are disclosed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resin composition for laser welding containing a luster pigment having a thermoplastic resin and a metal oxide layer, a molded product comprising the same, and a welded molded product obtained by laser welding the molded product.

  Thermoplastic resins have excellent moldability and shape flexibility. Moreover, since it has high designability etc., it is widely used for a motor vehicle, an electric electronics, and general industrial use. Among them, polyamide resin, polybutylene terephthalate resin, and polyphenylene sulfide resin are further excellent in chemical resistance, heat resistance, and electrical insulation and are used in many functional parts.

However, with the advancement of industry, various physical properties required for these thermoplastic resins are further improved and diversified.
In recent years, multiple parts have been welded to be integrated or combined, and laser welding using laser light is known in addition to vibration welding, ultrasonic welding, injection welding, hot plate welding, etc. It came to be.

For example, Patent Document 1 describes a laser welding method for a resin material.
In this method, a transparent resin material and a non-transparent resin material that are transparent to laser light are overlapped, and laser light is irradiated from the transparent resin material side, thereby combining the transparent resin material and the non-transmissive resin material. In this method, the surfaces are heated and melted to join them together. The laser light is transmitted through the transmissive resin material and absorbed by the non-transmissive resin material, and the laser light absorbed by the mating surface is accumulated. As a result, the non-transmissive resin material is heated and melted, and from the mating surface. This is a technique in which the permeable resin material is also melted by heat transfer to join them together.

  In order to suppress energy loss when the laser light passes through the transmissive resin material, a laser wavelength is selected and used so that the transmittance of the transmissive resin material is 26% or more.

  Patent Document 2 describes a laser welding method of a resin member that can be joined without causing a difference in color tone between a transmissive resin material and an absorbing resin material.

  Since the laser welding method requires a combination of a member that transmits laser light and a member that absorbs it, the transmitting member is white or transparent, and the absorbing member is a black laser light absorbing color. Therefore, there is a problem that the appearance is uncomfortable, but the appearance of discomfort is eliminated by reducing the laser welding strength by blending the laser light transmitting member with a colorant such as a black organic dye that does not absorb the laser light. be able to.

On the other hand, there are many demands for the thermoplastic resin to have a metallic color tone.
It is described that a resin molded product having a metallic appearance, that is, a metallic appearance, is obtained by mixing metal particles such as aluminum, copper, and tin into a thermoplastic resin.

  Patent Document 4 describes bright pigments and resin compositions using them.

This is a method of increasing the metallic color tone by mixing a bright pigment obtained by coating a transparent titania layer mainly composed of titanium dioxide on the surface of glass flakes with a thermosetting resin or a thermoplastic resin.
JP 2001-105499 A (page 1-2) JP 2001-71384 A (page 1-3) Japanese Examined Patent Publication No. 4-27932 (page 1-2) JP 2003-165924 A (page 1-2)

  However, Patent Document 1 only describes a technique for laser welding a thermoplastic resin molded product having a normal color tone, and does not describe a technique for laser welding a molded member having a metallic color tone.

  Further, Patent Document 2 describes laser welding of a molded product colored black with an organic dye, but does not describe a technique for laser welding a molded product having a metallic tone.

  Further, Patent Document 3 describes a technique for coloring in a silver metallic tone with aluminum flakes. However, since the material obtained by this technique reflects laser light, laser welding cannot be performed.

  Moreover, although the said patent document 4 is described about the technique which mix | blends the glass flake which has a titania layer with the thermoplastic resin for injection molding etc., what is described about the technique of laser-welding the obtained molded article. Absent.

  Therefore, as a result of searching for a thermoplastic material that is colored in a metallic tone and excellent in laser transmission, the present inventors have found that a thermoplastic resin blended with a specific bright pigment has excellent laser transmission and laser absorption thermoplasticity. The present inventors have found that it is possible to firmly weld by laser welding in combination with a resin molded product, and the present invention has been achieved.

That is, the present invention
(1) A laser welding resin composition comprising 0.5 to 2 parts by weight of a bright pigment having a metal oxide layer (B) with respect to 100 parts by weight of (A) thermoplastic resin,
(2) The laser welding resin composition according to (1), wherein the bright pigment having the (B) metal oxide layer is a bright pigment having a titania layer,
(3) Laser welding as described in (1) or (2), wherein the bright pigment having a metal oxide layer (B) has a metal oxide layer on an inorganic oxide or inorganic hydroxide substrate. Resin composition,
(4) The (A) thermoplastic resin is at least one selected from (A1) polyamide resin, (A2) polybutylene terephthalate resin, and (A3) polyphenylene sulfide resin. Laser welding resin composition,
(5) (C) At least one selected from inorganic fillers (excluding bright pigments having a metal oxide layer) and organic fillers is used in an amount of 1 to 200 with respect to 100 parts by weight of (A) thermoplastic resin. The laser welding resin composition according to any one of (1) to (4), wherein the resin composition is blended by weight part,
(6) The laser welding resin composition according to any one of (1) to (5), wherein the transmittance of laser light having a wavelength of 800 to 1100 nm is 15% or more when the molded product has a thickness of 2.0 mm.
(7) A molded product formed by molding the laser welding resin composition according to any one of (1) to (6),
(8) A welded molded product obtained by laser welding the molded product according to (7).

  As described above, the thermoplastic resin composition of the present invention has a metallic-like luster appearance and has a transmittance necessary for laser welding, so that high laser welding strength can be expressed, and automotive parts. It is useful for molded products that require laser welding and metallic-like luster appearance in electrical / electronic parts and general industrial equipment.

The present invention will be described in detail below.
Details of the present invention will be described below. In the present invention, “weight” means “mass”.

  The (A) thermoplastic resin used in the present invention is not particularly limited as long as it transmits laser light, and in particular, at least one selected from (A1) polyamide resin, (A2) polybutylene terephthalate resin, and (A3) polyphenylene sulfide resin. Species are preferably used. These resins are preferred because they have a high balance of chemical resistance, heat resistance, mechanical strength, and electrical insulation and are excellent in workability. These (A1) polyamide resin, (A2) polybutylene terephthalate resin, and (A3) polyphenylene sulfide resin may be used alone, polyamide and polyamide copolymer, polybutylene terephthalate and polybutylene terephthalate copolymer, polyphenylene sulfide. And a polyphenylene sulfide copolymer may be used in combination.

  (A1) The polyamide resin is a resin mainly composed of amino acid, lactam or diamine and dicarboxylic acid. Representative examples of the raw materials include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and paraaminomethylbenzoic acid, lactams such as ε-caprolactam and ω-laurolactam, tetramethylenediamine, hexa Methylenediamine, nonamethylenediamine, 2-methylpentamethylenediamine, undecamethylenediamine, dodecamethylenediamine, (2,2,4- or 2,4,4-) trimethylhexamethylenediamine, 5-methylnonamethylenediamine, Metaxylylenediamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, Bis (4-aminosi Chlohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine, aminoethylpiperazine, aliphatic, alicyclic, aromatic Diamines, and adipic acid, speric acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid Examples thereof include aliphatic, alicyclic and aromatic dicarboxylic acids such as acid, hexahydroterephthalic acid and hexahydroisophthalic acid. In the present invention, polyamide homopolymers or copolymers derived from these raw materials are used alone or It can be used in the form of a mixture.

  In the present invention, the (A1) polyamide resin that is particularly preferably used is a polyamide resin having a melting point of 200 ° C. or higher and excellent in heat resistance and strength. Specific examples include polycaproamide (nylon 6), poly Hexamethylene adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polyhexamethylene sebamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyhexamethylene terephthalamide (nylon 6T) ), Polynonamethylene terephthalamide (nylon 9T), polyhexamethylene isophthalamide (nylon 6I), polyxylylene adipamide (nylon XD6), polycaproamide / polyhexamethylene adipamide copolymer (nylon 6/66) , Polyhexamethylenete Phthalamide / polycaproamide copolymer (nylon 6T / 6), polyhexamethylene terephthalamide / polydodecanamide copolymer (nylon 6T / 12), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (nylon 66 / 6T), Polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6I), polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaproamide copolymer (nylon 66 / 6I / 6), polyhexamethylene azide Pamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I), polyhexamethylene terephthalamide / polyhexamethylene iso Talamide copolymer (nylon 6T / 6I), polyhexamethylene terephthalamide / poly (2-methylpentamethylene) terephthalamide copolymer (nylon 6T / M5T), polyhexamethylene terephthalamide / polyhexamethylene sebacamide / polycaproamide Copolymer (nylon 6T / 610/6), polyhexamethylene terephthalamide / polydodecanamide / polyhexamethylene adipamide copolymer (nylon 6T / 12/66), polyhexamethylene terephthalamide / polydodecanamide / polyhexamethylene isophthalate Examples thereof include amide copolymers (nylon 6T / 12 / 6I) and mixtures or copolymers thereof.

  Particularly preferred are nylon 6, nylon 66, nylon 610, nylon 6/66 copolymer and nylon 66 / 6I / 6 copolymer, and nylon 6T / 66 copolymer, nylon 6T / 6I copolymer, nylon 6T / 6 copolymer, nylon 6T. / 12 copolymer, nylon 6T / 12/66 copolymer, nylon 6T / 12 / 6I copolymer, and at least one polyamide selected from copolymers having hexamethine terephthalamide units. These polyamide resins are also practically suitable for use as a mixture depending on required properties such as moldability, heat resistance, toughness, and surface properties. The degree of polymerization of the polyamide used here is not particularly limited, but preferably has a relative viscosity measured in a range of 1.9 to 4.0 in 98% sulfuric acid concentration 1% and 25 ° C. according to JIS-K6920. A range of 0.0 to 3.5 is particularly preferable. When the relative viscosity is within this range, the moldability and mechanical properties are excellent, which is suitable for the present invention.

  (A2) Polybutylene terephthalate resin (hereinafter also referred to as component (A2)) used as a thermoplastic resin in the present invention is terephthalic acid (or an ester-forming derivative such as dimethyl terephthalate) and 1,4-butanediol (or A polymer obtained by polycondensation reaction using the ester-forming derivative) as a main raw material.

  The polybutylene terephthalate copolymer that can be used in combination with the polybutylene terephthalate includes terephthalic acid (or an ester-forming derivative such as dimethyl terephthalate) and 1,4-butanediol (or an ester-forming derivative thereof). And other dicarboxylic acids (or ester-forming derivatives thereof) or other diols (or ester-forming derivatives thereof) copolymerizable therewith.

  Examples of other dicarboxylic acids (or ester-forming derivatives thereof) include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, and anthracene dicarboxylic acid. 4,4′-diphenyl ether dicarboxylic acid, aromatic dicarboxylic acid such as 5-sodium sulfoisophthalic acid, aromatic dicarboxylic acid such as adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, 1,3-cyclohexanedicarboxylic acid, And alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid.

  The component (A2) is selected from (D) polycarbonate resin, acrylonitrile / styrene copolymer, polyphenylene oxide, styrene resin, acrylic resin, polyethersulfone, polyarylate, and polyethylene terephthalate resin (hereinafter also referred to as component D). It is also practically preferable to use at least one selected from the above as a mixture because of necessary characteristics such as moldability, toughness, and laser light transmission.

  When only the polybutylene terephthalate copolymer is used as the component (A2), the addition of at least one selected from polycarbonate resin, styrene resin, and polyethylene terephthalate resin may deteriorate moldability, which is not preferable. .

  The viscosity of the component (A2) is not particularly limited as long as it can be melt-kneaded. However, it is usually preferable that the intrinsic viscosity when an o-chlorophenol solution is measured at 25 ° C. is 0.36 to 1.60. . Further, when the component (A2) is composed of polybutylene terephthalate and polybutylene terephthalate copolymer, the physical or molten mixture is dissolved in o-chlorophenol after pulverization or in the form of pellets, and o-chloro The result of adjusting the phenol solution and measuring the viscosity only has to be within the viscosity condition.

  In the present invention, impact resistance and cold resistance can be imparted to the component (A2) by further blending an elastomer. Examples of such elastomers include ethylene and styrene. Here, the heat resistance refers to the resistance to cracking in a low temperature and high temperature repeated environment in a resin molded body formed by insert molding of a metal or the like, which is greatly different from a polybutylene terephthalate resin or the like. .

  The amount of addition of the elastomer is preferably 1 to 50 parts by weight from 100 parts by weight of component (A2) in terms of moldability such as fluidity and mold release.

  The (E) styrene-based elastomer as the elastomer can impart laser transmittance retention, impact resistance, and cold resistance by using a styrene-butadiene block copolymer (hereinafter also referred to as (E) component). Ethylene-based elastomers can impart impact resistance and cold resistance, but are not preferred because of their poor laser transmission.

  The (A3) polyphenylene sulfide resin used as a thermoplastic resin in the present invention is a polymer obtained by a polymerization reaction using dichlorobenzene and sodium sulfide as main raw materials.

  The polyphenylene sulfide resin used in the present invention is obtained by adding an alkali metal carboxylate, which is a polymerization aid during polymerization, and having a high molecular weight without heat treatment, such as laser transmission, impact resistance, and moldability. It is suitable for practical use from the required characteristics. On the other hand, from the viewpoint of laser transmittance, a polyphenylene sulfide resin that has not been polymerized by heat treatment can be preferably used.

  As the bright pigment (B) having a metal oxide layer used in the present invention, those having a titania layer on a substrate obtained from an inorganic oxide or an inorganic hydroxide can be preferably used. The titania layer is a layer containing titanium dioxide as a main component, and since the titania layer is transparent, the metallic appearance of the blended resin composition and the laser transmittance can both be achieved, which is preferable. As for visible light, the reflected light reflected on the titania surface and the reflected light reflected on the surface of the base material give a metallic-like bright color as an interference color due to an optical path difference. The refractive index difference between the base material and the titania layer is preferably 0.6 or more, and more preferably 0.8 or more from the viewpoint of giving the resin composition a metallic appearance.

  The thickness of the titania layer is preferably from 1 to 800 nm, and more preferably from 5 to 100 nm, in order to obtain glitter due to interference colors.

  Moreover, since the substance used as the base material of a luster pigment has the laser transmittance required for laser welding, an inorganic oxide or an inorganic hydroxide is preferable. In particular, a substrate made of glass, silica, aluminum oxide or the like is preferable.

  In order to increase the brightness of the luster pigment, a substrate shape having a smooth surface and a large surface area is preferred, and glass flakes are also preferred from the viewpoint of laser transmittance.

  The glass flakes preferably have an average thickness of 0.1 to 7 μm and an average particle size of 5 to 250 μm. Further, the aspect ratio (average particle size / average thickness) is preferably 10 or more, and when the average particle size exceeds 250 μm, the base material tends to crack in the thermoplastic resin during the melt-kneading process, When it is less than 5 μm, the luminance is remarkably reduced. On the other hand, when the average thickness is less than 0.1 μm, it is easy to break in the melt-kneading process, while when it exceeds 7 μm, the number of glitter pigment particles decreases and the glitter feeling is lowered.

  Here, the average particle diameter of the glass flakes is the number average measured by a square standard sieving method, and the aspect ratio is obtained by measuring the large diameter, the small diameter, and the thickness as measured by a microphotograph as the large diameter + small diameter / 2 · thickness. Value.

  The amount of the bright pigment added is (A) 100 parts by weight of the thermoplastic resin, and (B) 0.1-2 parts by weight of the bright pigment having the metal oxide layer is blended with the metallic appearance and laser transmittance. To 0.5, preferably 0.5 to 1.0 part by weight.

  By adding the bright pigment having the metal oxide layer (B) described above, high laser welding strength can be achieved by providing a metallic-like bright appearance and having the necessary transparency for laser welding. .

  On the other hand, a resin molded product that exhibits a metallic appearance, that is, a metallic appearance, by mixing metal particles such as aluminum, copper, and tin reflects laser light, and thus is not preferable as a laser welding transmission material.

  In the present invention, at least one selected from (C) an inorganic filler (excluding a bright pigment having a metal oxide layer) and an organic filler (hereinafter also referred to as component (C)) is further blended. Can do. As the component (C), fibers, granules, plates and the like can be used, but glass fiber, carbon fiber, potassium titanate whisker, zinc oxide whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber , Fibrous fillers such as ceramic fiber, asbestos fiber, gypsum fiber, metal fiber, wollastonite, zeolite, sericite, kaolin, mica, clay, pyrofilament, bentonite, asbestos, talc, aluminate silicate, alumina , Metal compounds such as silicon oxide, magnesium oxide, zirconium oxide, titanium oxide, iron oxide, carbonates such as calcium carbide, magnesium carbonate, dolomite, sulfates such as calcium sulfate, barium sulfate, glass beads, glass flakes, milled glass Fiber, ceramics bee , Boron nitride, silicon carbide, non-fibrous fillers such as silica and the like, and glass fiber from the laser permeable holding, glass flakes, milled glass fiber is preferably used. More preferable examples include glass fibers.

  Furthermore, it is more preferable to use these fillers after being pretreated with a coupling agent such as silane, epoxy, or titanate.

  The amount of the component (C) used in the present invention is preferably 1 to 200 parts by weight, more preferably 5 parts per 100 parts by weight of the thermoplastic resin (A) from the balance between fluidity and mechanical strength. It is -120 weight part, and 10-100 weight part is especially preferable.

  The laser welding resin composition used in the present invention further contains at least one selected from the group consisting of higher fatty acids having 12 or more carbon atoms, alkali metal salts, alkaline earth metal salts, esters and amide compounds. Can do.

  Alkali metal salts, alkaline earth metal salts, esters, amide compounds composed of higher fatty acids having 12 or more carbon atoms, acidic compounds and aluminum, barium, calcium, etc. are hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, sulfurous acid, nitrous acid. , Phosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, benzenesulfonic acid, p-toluenesulfonic acid, acetic acid, propionic acid, butyric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, behenic acid, isostearic acid Benzoic acid, o-toluic acid, m-toluic acid, p-toluic acid, succinic acid, malonic acid, succinic acid, adipic acid, sebacic acid, montanic acid, and the like. Polyamide resin, polybutylene terephthalate resin, polyphenylene Laurin due to its affinity with sulfide resin and mechanical properties, especially in terms of releasability during injection molding , Myristic acid, palmitic acid, stearic acid, oleic acid, behenic acid, fatty acids such as montanic acid are preferred. These fatty acids may be a single compound or a mixture of two or more.

  The blending amount of the higher fatty acid having 12 or more carbon atoms and the alkali metal salt, alkaline earth metal salt, ester, and amide compound used in the present invention is 0.005 to 1 with respect to 100 parts by weight of the (A) thermoplastic resin. Part by weight, preferably 0.05 to 0.5 part by weight. It is preferable to add 0.005 parts by weight or more, since an effect of improving the releasability is obtained, and setting the amount to 2 parts by weight or less can prevent deterioration of physical properties and mold contamination due to generated gas.

  The thermoplastic resin composition (A) of the present invention has other components such as weathering agents (resorcinol-based, salicylate-based, benzotriazole-based, benzophenone-based, hindered amine-based, etc.) and lubricants within the range not impairing the object of the present invention. (Montanic acid and its metal salt, its ester, its half ester, stearyl alcohol, stearamide, various bisamides, bisurea, polyethylene wax, etc.), pigment (cadmium sulfide, phthalocyanine, rylene, perylene, naphthacocyanin, quinacridone, carbon black , Titanium oxide, iron oxide, azo, monoazo, metal complex salts, etc.), dyes (azine, azo, perylene, anthraquinone, etc.), crystal nucleating agents (talc, polyether ether ketone, etc.), plasticizers ( Octyl p-oxybenzoate, N-butylbenzenes Honamide, etc.), antistatic agents (alkyl sulfate type anionic antistatic agents, quaternary ammonium salt type cationic antistatic agents, nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, betaine amphoteric antistatic agents Agents), flame retardants (for example, red phosphorus, melamine cyanurate, ammonium polyphosphate, brominated polystyrene, brominated polyphenylene ether, brominated polycarbonate, brominated epoxy resins, or these brominated flame retardants and antimony trioxide. Combinations), coloring inhibitors (hypophosphites, etc.), other polymers, and the like.

  The addition of the crystal nucleating agent increases the crystallization rate (solidification rate) and shortens the molding cycle. Further, the addition of pigments and dyes can improve the design of the molded product.

  Since these additives may have a synergistic effect by combining two or more kinds, they may be used in combination.

  What is necessary is just to implement about the manufacturing method of the thermoplastic resin composition of this invention by the method generally known, and it does not need to specifically limit. As a typical example, melt kneading (temperature: 230 to 300 ° C. (PA6, PA6 / 66 copolymerization, PBT, PBT, etc.) using a known melt mixer such as a single or twin screw extruder, a Banbury mixer, a kneader, or a mixing roll. ), 270-300 ° C. (N66), 290-350 ° C. (PPS)). Each component may be mixed in advance and then melt kneaded. Alternatively, for 100 parts by weight of the total amount of the components (A) to (E), for a small amount of additive component such as 1 part by weight or less, after other components are kneaded and pelletized by the above method, It can also be added before molding. In addition, although it is better that the water | moisture content adhering to each component is less and it is desirable to dry beforehand, not all the components need to be dried.

  As an example of a preferable production method, a twin-screw extruder is used (cylinder temperature: 230 to 300 ° C. (PA6, PA6 / 66 copolymerization, PBT), 270 to 300 ° C. (N66), 290 to 350 ° C. (PPS)). Examples include a method in which a filler component and a bright pigment other than the filler component are supplied and kneaded from the upstream side of the extruder, and then the filler and the bright pigment are side-fed and further kneaded. The side feed position of the bright pigment is preferably a position on the 1/5 to 4/5 discharge port side from the upstream end of the extruder when the total length from the upstream end of the extruder to the discharge port is 1.

  The resin composition of the present invention is generally molded by a known thermoplastic resin molding method such as injection molding, extrusion molding, blow molding, transfer molding, vacuum molding, etc., among which injection molding is preferable.

  In the present invention, it is preferable that the laser beam transmittance in the near-infrared 800 to 1100 nm wavelength region measured by using the thermoplastic resin composition as a molded article having a sample thickness of 2 mm is 15% or more. When the laser beam transmittance in the near-infrared 800 to 1100 nm wavelength region measured at a sample thickness of 2 mm is 15% or more, a high welding strength can be obtained when the laser welding resin composition of the present invention is laser welded. it can. In the present invention, (B) a bright pigment having a metal oxide layer is blended in an amount of 0.5 to 2 parts by weight with respect to 100 parts by weight of the thermoplastic resin (A), thereby giving a metallic appearance and further a laser beam. The transmittance can be in this range. The laser beam transmittance is preferably 16% or more. This is because by setting the content to 16% or more, high welding strength can be obtained without melting the laser incident surface of the transmission material during laser welding.

  Here, the transmittance of laser light having a wavelength of 800 to 1100 nm is obtained by using an ultraviolet near-infrared spectrophotometer (UV-3150) manufactured by Shimadzu Corporation, and a φ60 integrating sphere (manufactured by Shimadzu Corporation) ( It is a value performed using ISR-3100). The laser beam transmittance is obtained by measuring the beam transmission amount in the near infrared 800 to 1100 nm wavelength region using a sample having a thickness of 2 mm, and expressing the ratio between the transmitted light amount and the incident light amount as a percentage.

  In the measurement of the laser beam transmittance in the near infrared 800 to 1100 nm wavelength region, the laser beam transmittance is measured every 50 nm, and the maximum value and the minimum value of the laser beam transmittance in the near infrared 800 to 1100 nm wavelength region are obtained. Fig.2 (a) is a top view showing the laser beam transmittance evaluation test piece, and (b) is a side view showing the test piece. The laser beam transmittance evaluation test piece 8 had a rectangular parallelepiped shape with a base of square, a side L of the base of 80 mm, and a thickness D of 2 mm. The laser beam transmittance of 2 mm in thickness is measured by measuring the laser beam transmission amount of this test piece.

  The thermoplastic resin composition of the present invention is used as a material to be subjected to laser welding, taking advantage of the excellent properties having a metallic-like bright appearance and having the transmittance necessary for laser welding. It is suitable for a laser beam transmission side molded body of the welding method, and can be easily applied to a laser beam absorption side molded body by adding a near infrared absorber such as carbon black to the composition.

  The thermoplastic resin composition for laser welding according to the present invention has a metallic appearance without impairing the excellent properties inherent in polyamide resin, polybutylene terephthalate resin, and polyphenylene sulfide resin, and is a laser necessary for laser welding. It is a resin composition for laser welding in which high laser welding strength can be expressed by having transparency, and new characteristics which are lacking in polyamide resin, polybutylene terephthalate resin, and polyphenylene sulfide resin are provided. It can be applied to any application that requires tonal brightness. For example, switches, ultra-small slide switches, DIP switches, switch housing knobs, lamp sockets, cable ties, gaskets, connectors, connector housings, connector shells, IC sockets, coil bobbins, bobbin covers, relays, relay boxes , Condenser case, motor internal parts, motor case, gear cam, dancing pulley, spacer, insulator, fastener, buckle, wire clip, pump housing, bicycle wheel, caster, terminal block, power tool housing, starter insulation Parts, canister case, fuse box, air cleaner case, air conditioner fan, terminal housing, throttle housing, injector, wheel cover, engine Bar, timing belt cover, lamp bezel, bearing retainer, cylinder head cover, intake manifold, pipe (water pipe, air pipe, fuel pipe, LLC pipe, hydrogen pipe, oxygen pipe, etc.), tank (fuel tank, LLC reserve tank, Radiator tank, power steering reserve tank, brake fluid tank, washer tank, etc.), fuel filter housing / cover, impeller, clutch release bearing hub, automobile engine control unit housing / cover, brake control unit case / cover, sensor housing / cover ( Rotation sensor, position detection sensor acceleration sensor, pressure sensor, solar radiation sensor, temperature sensor, raindrop sensor, gravity sensor , Vehicle height sensor, ETC sensor, lane sensor, etc.), solenoid housing / cover, actuator housing / cover, air flow meter, door handle, sun visor arm, rearview mirror, ignition coil housing, door mirror stay bracket, electronic key housing, washer Represented by nozzles, computer housings, inverter housings / covers, reactor housings, ETC housings, mobile phone cases, remote control switch cases, speaker diaphragms, heat-resistant containers, microwave oven parts, rice cooker parts, printer ribbon guides, etc. Electrical / electronic related parts, automobile / vehicle related parts, home / office electrical product parts, computer related parts, facsimile / copier related parts, machine related parts, stationery etc. It is useful in various applications.

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples unless it exceeds the gist. Moreover, all the addition mixture ratios shown in the Examples and Comparative Examples are parts by weight. Each evaluation was measured according to the method described below.

(1) General mechanical properties, moldability Measured according to standard methods below. In addition, the test piece in the following tensile test, a bending test, etc. was created with Toshiba Machine's injection molding machine IS80EPN-2A (cylinder temperature: 320 (PPS), 280 ° C (PA66), 260 ° C (both PA6 and PA6 / 66). Polymerization, PBT), mold temperature: 130 ° C. (PPS), 80 ° C. (PA66, PA6, PA6 / 66 copolymerization, PBT), injection pressure: molding lower limit pressure + 12.8 MPa, injection time: 15 sec, cooling time: 15 sec ).

Moldability After filling and cooling the resin at the above temperature, pressure, injection time, and cooling time using a test piece mold, the resin test piece is greatly deformed when the resin test piece is ejected from the mold by the ejection pin. Or “x” indicates that the protruding portion is greatly buckled, and “◯” indicates that there is no deformation.

Tensile strength It was performed in accordance with ASTM D638. Using a No. 1 dumbbell-shaped test piece (test piece thickness: 1/8 inch (3.2 mm)), the test was conducted at 23 ° C. at a test speed of 10 mm / min.

Flexural modulus It was performed according to ASTM D790. The test was performed at 23 ° C. at a test speed of 1 mm / min using a bending test piece (test piece thickness: 1/4 inch (6.4 mm)).

Izod impact strength It was performed in accordance with ASTM D256. The test was performed at 23 ° C. using an impact test piece (test piece thickness: 1/8 inch (3.2 mm), cut notch).

The deflection temperature under load was performed in accordance with ASTM D648. A load deflection test piece (test piece thickness: 1/4 inch (6.4 mm)) was used, and the load stress was 1.82 MPa.

(2) Cooling and heat resistance A sprue 3 having a square columnar shape with a bottom side shown in FIG. 1 and having a shape in which the top side of a cone whose center is the intersection of diagonal lines on the top surface is cut off in parallel with the bottom surface of the cone. The insert molded product 1 formed by mounting on the upper surface of the rectangular column is (cylinder temperature: 260 ° C. (PBT), mold temperature: 80 ° C. (PBT), injection pressure: molding lower limit pressure + 12.8 MPa, injection (Time: 15 sec, cooling time: 15 sec).

  Fig.1 (a) is a top view of the said insert molded product, (b) is a side view of the molded product.

  The insert molded product 1 has an insert metal 4 mounted on a mold, a resin is injected from an injection molding machine, the injected resin is filled from a sprue 3 into a mold cavity so as to cover the insert metal 4, and a resin 2 The sprue 3 is solidified.

  Since the resin does not flow into the portion where the insert metal is mounted on the mold and the metal and the mold are in contact with each other, the resin unfilled portion 5 corresponding to the portion is formed on the bottom surface of the insert molded product 1.

  The length L of the side of the bottom (square) of the quadrangular prism portion of the insert molded product 1 is 50 mm, the height is 30 mm, and the thickness W of the resin 2 is 1.5 mm.

  The molded product was exposed for 1 hour in a 130 ° C. environment, further exposed for 1 hour in a −40 ° C. environment, and then subjected to a thermal cycle treatment in which the molded product was exposed again to a 130 ° C. environment, and the appearance of the molded product was visually observed. The number of cycles in which cracks occurred in the insert-molded product was shown in the table, and the magnitude of the value was used as an index for cold resistance.

(3) Laser transmittance (transmittance)
For the laser beam transmittance evaluation, a laser beam transmittance evaluation test piece 8 having a square L of 80 mm and a thickness D of 2 mm was used as the test piece. The injection molding conditions are: cylinder temperature: 320 (PPS), 280 ° C. (PA66), 260 ° C. (PA6, PA6 / 66 copolymerization, PBT), mold temperature: 130 ° C. (PPS) 80 ° C. (PA66, PA6, PA6) / 66 copolymerization, PBT), injection pressure: molding lower limit pressure + 12.8 MPa, injection time: 15 sec, cooling time: 15 sec).

  FIG. 2A is a plan view of the laser beam transmittance evaluation test piece, and FIG. 2B is a side view of the test piece.

  The laser beam transmittance evaluation test piece 8 comprises a sprue 3, a runner 6, and a gate 7. The gate 7 was cut and used as a laser beam transmittance evaluation test piece.

  The laser beam transmittance used was an ultraviolet / visible / near infrared spectrophotometer (UV-3150) manufactured by Shimadzu Corporation and a φ60 integrating sphere (ISR-3100) manufactured by Shimadzu Corporation. The laser beam incident angle is 0 degree. The laser beam transmittance represents the ratio between the transmitted light amount and the incident light amount as a percentage.

  For the laser beam transmittance, a wavelength region of near infrared rays of 800 to 1100 nm was measured every 50 nm using a sample having a thickness of 2 mm, and the minimum value and the maximum value were described in the table.

(4) Molded product color tone Evaluation of whether or not the luminescence of the bright pigment in the thermoplastic resin has a radiant feeling is performed using a test piece having the same shape as the laser transmittance evaluation test piece 8 of FIG. Place the test specimen plane parallel to the fluorescent lamp at a position 2 m below the white fluorescent lamp 40W x 2 vertically, 50 cm away from the sample, and 45 degrees obliquely upward from the specimen plane The overall evaluation results visually observed by five sensory testers are indicated in the table as “◯” when radiance is recognized and “X” when radiance is not recognized.

(5) Laser weldability The test piece is formed by cutting out two types of molded products from the same shape as the laser beam transmittance evaluation test piece 8 of FIG. 2, each having a width W of 25 mm and a length L. A laser welding test piece 9 having a thickness of 65 mm and a thickness D of 2 mm was used. FIG. 3 (a) is a plan view of the test piece after the processing, and b) is a side view thereof.

  As the laser welding machine, MODULAS C manufactured by Leister Co., Ltd. was used. This welding machine is a device using a semiconductor laser, and the wavelength of the laser beam is near infrared at 940 nm. The maximum output is 35 W, the focal length is 38 mm, and the focal diameter is 0.6 mm.

FIG. 4 is a schematic view showing an outline of the laser welding method.
As shown in FIG. 4, a laser welding test piece 13 using a material that transmits a laser beam is placed in the upper part, and a laser welding test piece 14 that uses a material that absorbs the laser beam is placed in the lower part. , Superimpose and irradiate laser beam from the top. The laser irradiation was performed along the laser welding trajectory 12, and the laser welding conditions were performed under the conditions that the best welding strength was obtained in the range of 15 to 35 W output and the laser scanning speed of 1 to 50 mm / sec. The focal length was fixed at 38 mm and the focal diameter was fixed at 0.6 mm.

  Whether or not laser welding is possible is described in the table as “Welding or not”. “Weldability” is “X” when a melt mark is observed on the light incident surface of the laser beam transmitting sample under the condition that it can be welded by laser beam irradiation, and “○” when no melt mark is observed and welding is possible. ".

FIG. 5A is a plan view of a laser welding strength measurement test piece laser-welded by the above method, and FIG. 5B is a side view of the test piece. The laser welding strength measurement test piece 15 was obtained by superposing the laser beam transmission side sample 13 and the laser beam absorption side sample 14 which are laser welding test pieces shown in FIG. The welding distance Y is 20 mm, and the welded portion 16 of the superposed transmission sample and absorption sample is laser welded.

  A general tensile testing machine (AG-500B manufactured by Shimadzu Corporation) was used to measure the welding strength, and both ends of the test piece were fixed with a chuck, and a tensile test was performed so that a tensile shear stress was generated at the welding site. . The welding strength was the stress when the welded site was broken. The strength measurement conditions were a tensile speed of 1 mm / min and a span of 40 mm.

  The laser beam transmission sample uses the thermoplastic resin of the present invention, the laser beam absorption side sample is the same resin as the laser transmission sample, and 43 parts by weight of glass fiber is added to 100 parts by weight of the resin. A material added with 0.4 part of carbon black was used. Laser weldability with a typical laser absorbing material was evaluated.

The compounding composition used for the Example and the comparative example below is shown.
(1) Polyamide 6 resin (PA6) Relative viscosity (ηr) 2.75
(2) Polyamide 66 resin (PA66) Relative viscosity (ηr) 2.75
(3) Polyamide 6/66 copolymer (PA 6/66) Relative viscosity (ηr) 2.75
Composition: Polyamide 6/66: 95/5 wt%
The relative viscosity was measured according to the method described in JIS K6920 using 98% sulfuric acid.

(4) PBT: polybutylene terephthalate resin Inherent viscosity 0.81 (measured at 25 ° C. using o-chlorophenol solution)
(5) PBT / I: polybutylene terephthalate / isophthalate copolymer composition: terephthalic acid / isophthalic acid: 90/10 mol%
Production method of PBT / I 450 parts of terephthalic acid (hereinafter also referred to as TPA), 50 parts of isophthalic acid (hereinafter also referred to as IPA) [TPA / IPA = 90/10 mol%], 407 parts of 1,4-butanediol, tetra -1 part of n-butyl titanate was charged into a reactor equipped with a rectifying column, and the temperature was gradually raised from 180 ° C to 230 ° C under a reduced pressure environment of 500 mmHg to allow the reaction to reach an esterification reaction rate of 95% or more. The polymerization was completed after 3 hours and 30 minutes by raising the temperature to 0.degree. The resulting copolymer was provided with an intrinsic viscosity of 0.80 (measured at 25 ° C. using an o-chlorophenol solution).

(6) PC: Polycarbonate resin Teflon A1900 manufactured by Idemitsu Petrochemical Co., Ltd.

(7) Elastomer (styrene)
Styrene-butadiene block copolymer epoxidized product, Epofriend A1010 manufactured by Daicel Chemical Industries, Ltd. (copolymerization ratio of styrene and butadiene: styrene / butadiene = 40/60 (weight ratio), epoxy equivalent 1000, MFR = 7 g / 10 min) (Measurement method: JIS-K7210)).

(8) Elastomer (Ethylene)
Ethylene-methyl acrylate-glycidyl methacrylate copolymer. The copolymerization ratio (weight ratio) of each component is ethylene unit / methyl acrylate unit / glycidyl methacrylate unit = 64/30/6 (% by weight). MFR = 9 g / 10 min (measurement method: JIS-K7210 (190 ° C., 2160 g load)).

(9) PPS resin-A (PPS-A)
In an autoclave equipped with a stirrer, 6.005 kg (25 mol) of sodium sulfide 9 hydrate, 0.656 kg (8 mol) of sodium acetate and 5 kg of NMP were charged, and the temperature was gradually raised to 205 ° C. through nitrogen, and 3.6 liters of water was distilled. I put it out. Next, after cooling the reaction vessel to 180 ° C., 3.756 kg (25.55 mol) of 1,4-dichlorobenzene and 2.4 kg of NMP were added, sealed under nitrogen, heated to 270 ° C., heated at 270 ° C. Reacted for 2.5 hours. Next, the mixture was put into 10 kg of NMP heated to 100 ° C., stirred for about 1 hour, filtered, and further washed with hot water at 80 ° C. for 30 minutes three times. This was put into 25 liters of an acetic acid aqueous solution of pH 4 heated to 90 ° C., and stirred for about 1 hour, filtered, washed with ion-exchanged water of about 90 ° C. until the pH of the filtrate reached 7, It was dried under reduced pressure at 80 ° C. for 24 hours to obtain a PPS resin-A having a cooling crystallization temperature of 215 ° C. and MFR of 100 g / 10 min. It used for Examples 20-23 (measurement method: JIS-K7210 (315.5 degreeC, 5000 g load)).

(10) PPS resin-B (PPS-B)
6.005 kg (25 mol) of sodium sulfide 9 hydrate and 5 kg of NMP were charged into an autoclave equipped with a stirrer, and the temperature was gradually raised to 205 ° C. through nitrogen, and 3.6 liters of water was distilled off. Next, after cooling the reaction vessel to 180 ° C., 3.763 kg (25.6 mol) of 1,4-dichlorobenzene and 1.8 kg of NMP were added, sealed under nitrogen, heated to 274 ° C., heated at 274 ° C. It reacted for 0.8 hours. The extraction valve provided at the lower part of the autoclave was opened at room temperature and normal pressure, the contents were extracted, and washed with hot water at 80 ° C. This was filtered, poured into 25 liters of an aqueous solution containing 10.4 g of calcium acetate, stirred for about 1 hour at 192 ° C. in a sealed autoclave, filtered, and the pH of the filtrate reached 7. After washing with ion-exchanged water at about 90 ° C., the polymer was dried at 120 ° C. for 8 hours and then heat-treated at 215 ° C. to obtain a PPS resin-B having a cooling crystallization temperature of 215 ° C. and MFR of 100 g / 10 min. It used for the following comparative examples 26-30 (measurement method: JIS-K7210 (315.5 degreeC, 5000 g load)).

  (11) GF: Glass fiber (average fiber diameter: 13 μm, chopped strand having a fiber length of 3 mm) was used.

(12) Bright pigment (a) Glass flake having a titania layer (glass flake / titania)
A luster pigment in which the entire surface of glass flakes having an average particle size of 90 μm and an average thickness of 5 μm was coated with rutile titanium dioxide with an average thickness of 0.05 μm by a liquid phase method was provided. (Nippon Sheet Glass Co., Ltd. “Metashine” MC5090RS)
(B) Glass Flake / Silver Coat A bright pigment having a surface of glass flake having an average particle diameter of 90 μm and an average thickness of 5 μm was coated with silver with an average thickness of 0.05 μm by an electroless plating method.

(C) Aluminum particles A
Plate-like aluminum particles having an average particle diameter of 5 μm and an average thickness of 1 μm were used as a luster pigment.

(D) Aluminum particle B
Plate-like aluminum particles having an average particle size of 30 μm and an average thickness of 5 μm were used as a bright pigment.

(E) Aluminum particles C
Plate-like aluminum particles having an average particle diameter of 60 μm and an average thickness of 7 μm were used as a luster pigment.

  (13) Organic pigment: An organic pigment mixed in monoazo lake / monoazo yellow / phthalocyanine blue: 35/14/51 (weight ratio) was used.

(14) Crystal nucleating agent: provided with talc. (Takehara Chemical Industry “HITRON” weight average particle size 5.3 μm)
Examples 1-12, Comparative Examples 1-12
The manufacturing method of the material described in Examples 1-12 and Comparative Examples 1-12 is as follows. That is, it was produced using a twin screw extruder having a screw diameter of 57 mm set to a cylinder temperature of 260 (PA6, PA6 / 66 copolymerization) and 280 (PA66). Component (A1) (polyamide resin) and other additives are fed from the original filling section, and the glass fiber and bright pigment are added from the side feeder and melt kneaded, and the strand discharged from the die is placed in the cooling bath. After cooling, it was pelletized with a strand cutter. Each material obtained was dried for 24 hours in a vacuum dryer at 80 ° C., and then molded and evaluated using the method described in the evaluation method.

  The formulation and results of Examples 1 to 12 and Comparative Examples 1 to 12 are shown in Tables 1 and 2.

  Both the non-reinforced polyamide resin composition and the glass fiber reinforced polyamide resin composition obtained in the present invention are excellent in metallic luster and have a thickness of 2 mm on the laser transmission side for laser welding. High laser beam transmissivity necessary for performing high welding strength without causing melting marks on the incident surface of the laser beam transmitting side sample when laser welding is performed using a 2 mm thick transmission material sample. showed that.

  On the other hand, the resin compositions obtained in Comparative Examples 1 to 12 have a low laser beam transmittance even though they have glitter, so that when laser welding is performed using a 2 mm-thick material as a transmission material sample, the laser beam transmission is achieved. There was a problem that melting marks were generated on the incident surface of the side sample.

Examples 13 to 19 and Comparative Examples 13 to 25
The methods for producing the materials described in Examples 13 to 19 and Comparative Examples 13 to 25 are as follows. That is, it was manufactured using a twin screw extruder having a screw diameter of 57 mm set at a cylinder temperature of 250 ° C. Component (A2) (polybutylene terephthalate-based resin), component (D) (polycarbonate resin), component (E) (elastomer), and other additives are supplied from the original container, and glass fiber and glitter pigment are supplied from the side feeder. Then, melt kneading was performed, and the strand discharged from the die was cooled in a cooling bath, and then pelletized with a strand cutter. Each obtained material was dried for 3 hours with a hot air dryer at 130 ° C., and then molded and evaluated using the method described in the evaluation method.

  The formulation and results of Examples 13 to 19 and Comparative Examples 13 to 25 are shown in Tables 3 and 4.

  Both the non-reinforced polybutylene terephthalate resin composition and the glass fiber reinforced polybutylene terephthalate resin composition obtained in the present invention are excellent in metallic luster and a 2 mm thick sample on the laser transmission side. When laser welding is performed using a laser beam having a high laser beam transmission property necessary for laser welding using a 2 mm-thick material as a transmission material sample, melting marks are generated on the incident surface of the laser beam transmission side sample. And showed high welding strength.

  In addition, when an elastomer is added to the glass fiber reinforced polybutylene terephthalate resin obtained in the present invention, and when an elastomer and a colorant, and an elastomer and a nucleating agent are further added and blended, the heat resistance and impact resistance are improved. In addition to improvement, it was possible to achieve both improvement in design by coloring, shortening of the molding cycle, and maintenance of metallic luster and laser beam transmission capable of laser welding. The resin composition obtained in the present invention has high laser beam transmissivity necessary when laser welding is performed using a 2 mm thick sample on the laser transmitting side, and the 2 mm thick sample is used as a transmitting material sample. In the case of laser welding, a high welding strength was exhibited without generating melting marks on the incident surface of the laser beam transmission side sample.

  On the other hand, since the resin compositions obtained in Comparative Examples 13 to 25 have poor glitter or have a glitter, the laser beam transmittance is low. In addition, there was a problem that melting marks were generated on the incident surface of the laser beam transmission side sample.

Examples 20-23, Comparative Examples 26-30
The manufacturing method of the material described in Examples 20-23 and Comparative Examples 26-30 is as follows. That is, it was manufactured using a twin screw extruder having a screw diameter of 57 mm set at a cylinder temperature of 320 ° C. Component (A3) component (polyphenylene sulfide resin) and other additives are supplied from the side feeder, glass fiber and bright pigment from the side feeder, melt kneaded, and the strand discharged from the die is cooled in a cooling bath. And then pelletized with a strand cutter. Each obtained material was dried for 3 hours with a hot air dryer at 130 ° C., and then molded and evaluated using the method described in the evaluation method.

  Table 5 shows the formulation and results of Examples 20 to 23 and Comparative Examples 26 to 30.

  The non-reinforced polyphenylene sulfide resin composition and the glass fiber reinforced polyphenylene sulfide resin composition obtained in the present invention are both excellent in metallic luster and laser using a 2 mm thick sample on the laser transmission side. High laser beam transmission required for performing welding, and when laser welding is performed using a 2 mm-thick sample as a transmission material sample, it is high without causing melting marks on the incident surface of the laser beam transmission side sample. The welding strength was shown.

  On the other hand, the resin compositions obtained in Comparative Examples 26 to 30 have a low laser beam transmittance even if they have glitter. Therefore, when laser welding is performed using a 2 mm thick material as a transmission material sample, the laser beam transmission is achieved. There was a problem that melting marks were generated on the incident surface of the side sample.

It is a figure which shows the shape of a heat-resistant test piece. It is a figure which shows the shape of the measurement test piece of a laser transmittance. It is a figure which shows the shape of a laser weldability test piece. It is a figure which shows the laser welding method. It is a figure which shows the shape of the test piece for laser welding strength measurement.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insert molded product 2 Resin 3 Sprue 4 Insert metal 5 Resin filling terminal part 6 Runner 7 Gate 8 Laser beam transmittance evaluation test piece 9 Laser welding test piece 10 Laser beam irradiation part 11 Laser beam 12 Laser beam orbit 13 Laser beam Transmission side test piece 14 Laser beam absorption side test piece 15 Laser welding strength measurement test piece 16 Laser welding portion

Claims (8)

(A) A laser welding resin composition obtained by blending 0.5 to 2 parts by weight of a bright pigment having a metal oxide layer (B) with respect to 100 parts by weight of a thermoplastic resin. (B) The laser welding resin composition according to claim 1, wherein the bright pigment having a metal oxide layer is a bright pigment having a titania layer. (B) The laser welding resin composition according to claim 1 or 2, wherein the bright pigment having a metal oxide layer has a metal oxide layer on an inorganic oxide or inorganic hydroxide substrate. The laser welding resin composition according to any one of claims 1 to 3, wherein (A) the thermoplastic resin is at least one selected from (A1) polyamide resin, (A2) polybutylene terephthalate resin, and (A3) polyphenylene sulfide resin. object. (C) At least one selected from inorganic fillers (excluding bright pigments having a metal oxide layer) and organic fillers is blended in an amount of 1 to 200 parts by weight per 100 parts by weight of (A) thermoplastic resin. The resin composition for laser welding according to any one of claims 1 to 4. The resin composition for laser welding according to any one of claims 1 to 5, wherein when a molded product having a thickness of 2.0 mm is formed, the transmittance of laser light having a wavelength of 800 to 1100 nm is 15% or more. A molded article formed by molding the laser welding resin composition according to claim 1. A welded molded product obtained by laser welding the molded product according to claim 7.

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