JP2007023263A - Thermoplastic resin composition for laser beam welding use and composite molded form using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an excellent colored resin composition for laser beam welding use expressing highly thermally stable dark-based achromatic color, with no decline in product design degree of freedom by injection molding, and applicable as a laser beam transmission-side molded form. <P>SOLUTION: The colored resin composition for laser beam welding use is obtained by compounding (A) 100 pts.wt. of a thermoplastic resin with (B) 0.01-5 pt(s).wt. of an Mn-free metal oxide such as cobalt oxide, a Co-Al compound oxide, Cr-Fe compound oxide or Co-Cr-Fe compound oxide. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser-welded thermoplastic colored resin composition having extremely excellent laser weldability and a composite molded body using the same, and further to a composite molded body obtained by laser welding to another article. .

  Conventionally, in joining each part made of a thermoplastic resin due to a complicated product shape, joining by an adhesive, mechanical joining by a bolt or the like has been performed. However, adhesives have problems of adhesive strength, and mechanical joining with bolts and the like has problems of cost, labor for fastening, and weight increase. On the other hand, external heat welding such as laser welding and hot plate welding, friction heat welding such as vibration welding and ultrasonic welding can be performed in a short time, and no adhesive or metal parts are used. Since problems such as cost, weight increase and environmental pollution do not occur, assembly by these methods is increasing.

  Laser welding, which is one of the external heating weldings, is, for example, irradiating a laser beam onto a superimposed resin molded body as disclosed in Patent Document 1, transmitting one irradiated and absorbing the other to melt, It is a method of fusion, and is a method that is spreading in a wide range of fields by taking advantage of three-dimensional joining, non-contact processing, and the absence of burrs.

  In this construction method, in the resin material applied to the laser beam transmission side molded body, the characteristic of transmitting the laser beam is essential, and when a molded body having a low laser beam transmittance is used for the laser beam transmission side molded body, The possibility of causing problems such as smoking is suspected.

  Unlike amorphous thermoplastic resins, crystalline thermoplastic resins such as polyphenylene sulfide, which are widely used to replace metals in various applications, have low laser beam transmittance, and thermoplastic resins are used as laser beams. When using the laser welding method as a molded product on the transmission side, the thickness limit is very strict due to its low laser beam transmittance, and it is necessary to deal with thinning to improve the laser beam transmittance. The degree of design freedom was small. Furthermore, there are cases in which thermoplastic resin products require dark achromatic colors such as gray, depending on the part used, from the standpoint of color balance with other parts and product design. Similarly, in the transmission side molded product of the welding method, dark coloring that transmits laser light is required. In the coloring with a carbon black which is a well-known technique for coloring thermoplastic resins, the laser welding method cannot be applied to the transmission side molded product because a laser beam is not transmitted even by adding a small amount. Therefore, studies on coloring dyes and organic pigments have been advanced.

As a coloring technique for laser transmission with dyes or organic pigments, Patent Document 2 relates to a laser light transmitting colored thermoplastic resin composition containing a triphenylmethane salt forming dye, and Patent Document 3 discloses disazo. Patent Document 4 describes a laser light transmitting colored thermoplastic resin composition containing a salt-forming dye, and Patent Document 4 describes a laser light transmitting polypropylene resin composition containing a dioxazine pigment. However, any of the above dyes and organic pigments is used when the molded product is exposed to a high temperature environment or when applied to a thermoplastic resin having a processing temperature of around 300 ° C., such as a polyphenylene sulfide resin, among crystalline resins. However, due to the poor thermal stability of the colorant itself, there are problems such as discoloration and fading in a high temperature environment, molding defects due to colorant decomposition during injection molding, and mold contamination.
JP-A-60-214931 (pages 2 and 3) JP 2004-155888 A JP 2004-168997 A JP 2004-224925 A

  The present invention solves the above-described conventional problems, and even in thermoplastic resins having a high melting point such as polyphenylene sulfide, it exhibits a dark achromatic color with excellent thermal stability for laser transmission, and injection molding. It is an object of the present invention to provide an excellent laser-welded colored resin composition that can be applied as a laser beam transmission side molded product without reducing the degree of freedom in product design.

  As a result of intensive studies to solve the above problems, the present inventors have reached the present invention.

That is, the present invention
(1) A thermoplastic colored resin composition for laser welding, comprising 0.01 to 5 parts by weight of (B) a metal oxide not containing Mn with respect to 100 parts by weight of (A) thermoplastic resin.

  (2) (B) The thermoplastic colored resin for laser welding according to the above (1), wherein the metal oxide not containing Mn contains an oxide of at least one metal selected from Fe, Cr, Co and Al. Composition.

  (3) The above (B), wherein the metal oxide not containing Mn is at least one selected from cobalt oxide, Co—Al composite oxide, Cr—Fe composite oxide and Co—Cr—Fe composite oxide ( 2) The thermoplastic coloring resin composition for laser welding as described.

  (4) The thermoplastic colored resin composition for laser welding according to the above (1) to (3), wherein the melting point of the thermoplastic resin (A) is a crystalline resin having a temperature of 220 ° C. or higher.

  (5) The laser-colored thermoplastic coloring resin composition according to any one of (1) to (4), wherein the thermoplastic resin is a polyphenylene sulfide resin having a temperature lowering crystallization temperature of 205 ° C. or lower.

  (6) (A) 1 selected from (C1) a glass fiber having a single fiber diameter of 12 μm or more and (C2) a non-fibrous filler having an average particle diameter of 30 μm or more with respect to 100 parts by weight of the thermoplastic resin. The thermoplastic colored resin composition for laser welding according to any one of (1) to (5), wherein 1 to 600 parts by weight of at least one kind of (C) filler is blended.

  (7) The thermoplastic colored resin composition for laser welding according to the above (6), wherein the refractive index of the filler (C) is 1.6 to 1.8.

  (8) The laser welding according to any one of (1) to (7), further comprising (D) an antioxidant in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the thermoplastic resin (A). Thermoplastic coloring resin composition.

  (9) A molded article on the laser beam transmission side comprising the thermoplastic colored resin composition for laser welding according to any one of the above (1) to (8), wherein the thickness of the transmission part of the welded part is 5 mm or less. Characterized product for laser welding.

  (10) A composite molded article obtained by laser welding a molded article comprising the colored resin composition for laser welding according to any one of (1) to (9).

  As will be described below, the laser-colored thermoplastic colored resin composition of the present invention is a dark-colored material that has excellent heat resistance and less discoloration when exposed to high-temperature environments, and less mold contamination during injection molding. Has a color tone. In addition, because it has laser permeability that can be laser welded, it is possible to obtain molded products with extremely excellent laser weldability, including electrical and electronic equipment, precision machinery equipment, office equipment, automobile and vehicle parts, It is useful for laser welding of resin moldings for various uses such as building materials, packaging materials, furniture, and household goods.

  Embodiments of the present invention will be described below. In the present invention, “weight” means “mass”.

  The thermoplastic coloring resin composition for laser welding of the present invention is obtained by blending 0.01 to 5 parts by weight of (B) Mn-free metal oxide with respect to 100 parts by weight of (A) thermoplastic resin. (B) The metal oxide not containing Mn preferably contains an oxide of at least one metal selected from Fe, Cr, Co and Al. Further, in the laser colored thermoplastic colored resin composition of the present invention, it is more effective for a crystalline thermoplastic resin having a melting point of 220 ° C. or higher, which requires heat resistance of the colorant, and among these, the melting point of the resin is further increased. It is effective for high polyphenylene sulfide resin (hereinafter referred to as PPS resin). Furthermore, the said composition can be adjusted by selecting suitably the compounding quantity etc. of a filler.

(1) Thermoplastic resin As an example of the thermoplastic resin used in the present invention, a known thermoplastic resin used as a resin for plasticizing by heating and performing a molding process can be exemplified. Typical examples include polyethylene resin, polypropylene resin, polystyrene resin, polymethylpentene resin, methacrylic resin, acrylic polyamide resin, ethylene vinyl alcohol resin, polycarbonate resin (PC), polyethylene terephthalate resin (PET), and polybutylene terephthalate. Polyester resin such as resin (PBT), polyamide resin (PA), polyacetal resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyphenylene oxide resin, polyphenylene sulfide resin, polyarylate resin, polyallyl sulfone resin, fluorine resin, liquid crystal Resin, cycloolefin polymer, cycloolefin copolymer, polyphenylene ether resin, polysulfone resin, polyethersulfone resin, polyether Ruimido resins, and polyamide-imide resins.

  Also, two or more copolymer resins of the thermoplastic resins can be used. For example, acrylonitrile-styrene copolymer resin, acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile-EPDM-styrene copolymer resin, PA-PBT copolymer resin, PET-PBT copolymer resin, PC-PBT copolymer Examples thereof include a polymer resin and a PC-PA copolymer resin.

  The molecular weight of these thermoplastic resins is not particularly limited, and for the purpose of improving the mechanical properties, heat resistance, dimensional properties, chemical resistance, moldability of the thermoplastic colored resin composition for laser welding, Two or more of these thermoplastic resins can also be mixed and used.

(2) Crystalline resin The thermoplastic coloring resin composition for laser welding according to the present invention is particularly effective for a crystalline resin having a melting point of 220 ° C. or higher, which requires heat resistance of the colorant. Polyamide resins such as polyamide 6 resin and polyamide 66 resin obtained by the production method, PBT resin, PPS resin and the like can be mentioned. Among these, a PPS resin having a particularly high melting point can effectively exhibit the effects of the present invention.

  Here, the melting point of the crystalline resin was obtained by collecting about 10 mg from the crystalline resin pellet as a sample, and using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer Co., Ltd., and raising the temperature at a heating rate of 20 ° C./min. The melting point peak (endothermic peak) temperature is measured and taken as the melting point.

(3) PPS resin The PPS resin in the thermoplastic resin used in the present invention is a polymer having a repeating unit represented by the following structural formula.

  A polymer containing 70 mol% or more, particularly 90 mol% or more of the repeating unit represented by the above structural formula is preferable from the viewpoint of heat resistance. Moreover, PPS resin can be comprised with the repeating unit etc. which have the following structure in less than 30 mol% of the repeating unit.

  The PPS resin used in the present invention preferably has a cooling crystallization temperature of 205 ° C. or lower. Here, the temperature-falling crystallization temperature was obtained by taking about 10 mg as a sample from the pellets of the thermoplastic colored resin composition, and using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer Co., Ltd., at a rate of temperature rise of 20 ° C./min. Then, after holding at 340 ° C. for 5 minutes, the temperature of the crystallization peak (exothermic peak) when the temperature is lowered at a rate of 20 ° C./min is measured, and the temperature is taken as the lowered crystallization temperature.

  The temperature-falling crystallization temperature of the PPS resin used in the present invention is further preferably 200 ° C. or lower, and more preferably 195 ° C. or lower. The lower limit is preferably 170 ° C. or higher in terms of heat resistance. In order to obtain a PPS resin having a low temperature-falling crystallization temperature, it is preferable to use a PPS resin having a large molecular weight (low melt flow rate (MFR)). The MFR of the PPS resin is preferably 500 g / 10 min or less, particularly preferably 350 g / 10 min or less, and further preferably 200 g / 10 min or less. The lower limit of MFR is preferably 30 g / 10 min or more in terms of fluidity loss. The MFR is a value obtained by drying 5 g of PPS resin powder at 130 ° C. for 3 hours and retaining the powder at 315.5 ° C. for 5 minutes, applying a 5 kg load (based on JIS-K7210).

  Further, copolymerization of a metaphenylene sulfide unit and a paraphenylene sulfide unit is preferable because the temperature-lowering crystallization temperature can be lowered as the melting point is lowered. Furthermore, it is preferable to use a trihalo or higher polyhaloaromatic compound together at the start of polymerization because a branched or crosslinked polymer is formed and the temperature-falling crystallization temperature can be lowered.

(Polymerization of PPS resin)
Generally, PPS resin is a method for obtaining a polymer having a relatively small molecular weight as described in JP-B-45-3368, or as described in JP-B-52-12240 and JP-A-61-7332. It can be produced by a method for obtaining a polymer having a large molecular weight.

  The difference between the former and the latter is the presence or absence of an alkali metal carboxylate as a polymerization aid in the polymerization system.

  In the former, since no alkali metal carboxylate is added to the polymerization system, the degree of polymerization does not increase, the molecular weight is relatively small, and the temperature-falling crystallization temperature is high. Moreover, since it is a polymer that also contains a large amount of impurities, it is colored by heating at the time of producing a composition or a molded article, and the laser weldability is lowered.

  In the latter case, an alkali metal carboxylate is added to the polymerization system, so that the degree of polymerization is increased, the molecular weight is relatively large, the temperature-falling crystallization temperature is lowered, and it is relatively easy to be within the scope of the present invention. In addition, the content of impurities is small, coloring due to heating can be suppressed, and laser weldability is excellent.

  The latter can satisfy the conditions defined in the present invention relatively easily. However, it is possible to adjust the fluidity of the PPS resin by using the former PPS resin together.

  In addition, a polyphenylene sulfide copolymer containing a paraphenylene sulfide unit and a metaphenylene sulfide unit as the repeating unit of the PPS resin as compared with a polymer having only a paraphenylene sulfide unit is preferable because the temperature-falling crystallization temperature is lowered. The molar fraction of the copolymerization ratio is preferably 1 mol% or more, more preferably 3 mol% or more, based on the total amount of metaphenylene sulfide units and paraphenylene sulfide units. The upper limit is preferably less than 30 mol% from the viewpoint of heat resistance. As the copolymerization mode, either random copolymerization or block copolymerization may be used, but random copolymerization is preferred from the viewpoint of a balance between laser weldability and heat resistance.

  Furthermore, it is preferable to use a trihalo or higher polyhaloaromatic compound together at the start of polymerization because a branched or crosslinked polymer is formed and the temperature-falling crystallization temperature can be lowered. The molar fraction of the copolymerization amount of the polyhaloaromatic compound is preferably 0.01 mol% or more of the polyhaloaromatic compound relative to the total amount of the polyhaloaromatic compound and the dihaloaromatic compound, and 0.04 mol. % Or more is particularly preferable, and 0.06 mol% or more is more preferable. The upper limit is preferably 0.1 mol% or less from the viewpoint of fluidity loss. Specific examples of the polyhaloaromatic compound include 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-tribromobenzene, 1,2,4-tribromobenzene and the like. It is done. In addition, active hydrogen-containing halogen aromatic compounds and halogen aromatic nitro compounds can be used in combination with dihaloaromatic compounds.

(Post-processing)
In the present invention, post-treatment such as heat treatment, organic solvent washing, and acid treatment can be performed in order to improve laser weldability and lower mechanical properties by lowering the crystallization temperature from the PPS resin.

  The heat treatment can be performed for the purpose of removing impurities that cause coloring. However, excessive heat treatment causes oxidation coloring and is not preferable because laser weldability is lowered. As for specific heat treatment conditions, the PPS resin is usually heated at a high temperature of 200 to 260 ° C., but in such a high temperature range, it causes oxidation coloring, and therefore in the present invention, 120 to 220 ° C., preferably It is good to carry out in the temperature range of 150-200 degreeC. The heating time is preferably 5 to 20 hours, more preferably 10 to 15 hours. The atmosphere of the heat treatment is usually performed in an oxygen atmosphere or a nitrogen atmosphere. However, in an oxygen atmosphere, the laser welding property is remarkably lowered due to oxidation coloring, and therefore a nitrogen atmosphere is preferable.

  Next, organic solvent cleaning of the PPS resin will be described. Organic solvent cleaning is preferable because impurities that cause coloring can be removed. The organic solvent used for washing the PPS resin is not particularly limited as long as it does not have an action of decomposing the PPS resin. For example, N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP), dimethylformamide, dimethylacetamide, Nitrogen-containing polar solvents such as 1,3-dimethylimidazolidinone, hexamethylphosphoramide, piperazinones, sulfoxide / sulfon solvents such as dimethyl sulfoxide, dimethyl sulfone, sulfolane, ketones such as acetone, methyl ethyl ketone, diethyl ketone, acetophenone Solvents, ether solvents such as dimethyl ether, dipropyl ether, dioxane, tetrahydrofuran, chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchlorethylene, monochloroethane, dichloro Halogen solvents such as tan, tetrachloroethane, perchlorethane, chlorobenzene, alcohols and phenols such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, polypropylene glycol Examples of the solvent include aromatic hydrocarbon solvents such as benzene, toluene, and xylene. Among these organic solvents, use of NMP, acetone, dimethylformamide, chloroform and the like is particularly preferable. These organic solvents are used alone or in combination of two or more.

  As a method of washing with an organic solvent, there is a method of immersing a PPS resin in an organic solvent, and it is preferable to stir or heat for the purpose of making the effect of the present invention more remarkable. Although there is no restriction | limiting in particular in the usage-amount of the organic solvent with respect to PPS resin, it is preferable that it is 1-100 kg with respect to 1 kg of dried PPS resin, It is more preferable that it is 2-50 kg, It is further 3-15 kg preferable.

  There is no restriction | limiting in particular about the washing | cleaning temperature at the time of wash | cleaning PPS resin with an organic solvent, Arbitrary temperature of about normal temperature-about 300 degreeC can be selected. However, since cleaning efficiency tends to increase as the cleaning temperature increases, it is preferable to perform cleaning at a high temperature of 100 to 300 ° C.

  It is also possible to wash in a pressure vessel under pressure (preferably 250 to 300 ° C.) at a temperature equal to or higher than the boiling point of the organic solvent. Also, the cleaning time is not particularly limited, but for the purpose of making the effect of the present invention more prominent, it is preferable to perform cleaning for 30 to 60 minutes or more in the case of batch cleaning. It is also possible to wash in a continuous manner.

  When the PPS resin produced by polymerization is washed with an organic solvent, it is preferably combined with water washing in order to further exhibit the effects of the present invention. Further, when a high-boiling water-soluble organic solvent such as N-methylpyrrolidone is used, it is preferable that the remaining organic solvent can be removed relatively easily by washing with water after washing with the organic solvent. The water used for these washings is preferably distilled water or deionized water. The water washing temperature is preferably 50 to 90 ° C, and preferably 60 to 80 ° C.

  Next, the acid treatment will be described. It can be carried out for the purpose of removing impurities that cause oxidative coloring or improving the mechanical properties. However, excessive acid treatment is not preferable because the terminal substitution reaction of the PPS resin proceeds to raise the temperature-falling crystallization temperature and lower the laser weldability. Specific acid treatment conditions will be described. The acid used for the acid treatment of the PPS resin is not particularly limited as long as it does not have an action of decomposing the PPS resin, but acetic acid, silicic acid, carbonic acid, and propyl acid are preferable, and acetic acid is more preferable. For example, acid treatment with a strong acid such as hydrochloric acid, sulfuric acid, phosphoric acid or the like having a pH of 2 or less causes excessive acid treatment, and the temperature-falling crystallization temperature rises, which tends to be undesirable in terms of laser weldability. is there. In addition, it is not preferable to decompose or deteriorate the PPS resin such as nitric acid.

  The acid treatment method includes a method of immersing the PPS resin in an acid or an aqueous solution of the acid, and is preferably stirred or heated for the purpose of making the effect of the present invention more remarkable, and the treatment time is 30 to 30 minutes. It is preferable that it is 60 minutes or more. Moreover, about the acid used for the acid treatment of PPS resin, it is preferable that pH is 3.5-5.5, and it is preferable that the usage-amount is 2-100 kg with respect to 1 kg of dried PPS resins, and 4-50 kg. It is more preferable that it is 5 to 15 kg. There is no restriction | limiting in particular in process temperature, Usually, it can carry out at room temperature, and when heating, it can carry out at 50-90 degreeC. For example, when acetic acid is used, it is preferable to immerse the PPS resin powder in an aqueous solution of PH4 kept at room temperature and stir for 30 to 60 minutes or more. The acid-treated PPS resin is washed several times with water in order to physically remove the remaining acid or salt. The water washing temperature is preferably 50 to 90 ° C, and preferably 60 to 80 ° C.

  As the water used for washing, distilled water and deionized water are used in the sense that the effects of the present invention and preferred chemical modification of the PPS resin by acid treatment are not impaired. In the present invention, the above post-processing can be combined and can be repeated a plurality of times.

(2) Metal oxide In the present invention, (B) Mn-free metal oxide is used in order to color the laser-colored thermoplastic colored resin composition in a dark achromatic color and to impart laser beam transparency. It is necessary to add the product as a pigment. In addition, the metal oxide shown here contains a complex oxide pigment, and from the viewpoint of color developability and processability when added to a thermoplastic resin, the average particle diameter is in the range of 0.01 to 50 μm. It is preferable that there is, and more preferably 0.04 to 5 μm. The average particle diameter is measured by plotting the particle amount (%) in each particle diameter section using a laser diffraction particle size distribution analyzer SALD-3100 manufactured by Shimadzu Corporation, and D50 (average particle diameter) from the accumulated distribution curve. )

  (B) Among metal oxides not containing Mn, pigments containing at least one metal oxide selected from Fe, Cr, Co and Al are preferred. Specific examples include, for example, cobalt oxide, Co -Al composite oxide, Co-Al-Cr composite oxide, Cr-Fe composite oxide, Co-Cr-Fe composite oxide, Ti-Sb-Cr composite oxide, Fe-Zn-Cr composite oxide, Fe -Ni-Al composite oxide, Ti-Zn-Ni-Co composite oxide, Ti-Ni-Co composite oxide, Ti-Sb-Ni composite oxide, Ti-Sb-Cr composite oxide, Zn-Fe composite Examples thereof include oxides, Zn—Fe—Cr composite oxides, Ti—Zn—Co—Ti composite oxides, Co—Al—Cr—Ti composite oxides, and Cu—Cr composite oxides.

  In the present invention, among the above metal oxides, (B) a metal oxide not containing Mn is cobalt oxide from the viewpoint of laser light transmission essential for laser weldability and dark achromatic coloring. Particularly preferred is at least one selected from Co—Al composite oxide, Cr—Fe composite oxide and Co—Cr—Fe composite oxide.

  The blending amount of (B) is 0.01 to 5 parts by weight, preferably 100 parts by weight of (A) thermoplastic resin, preferably from the balance of laser transmission, color tone, mechanical strength, and the like. 0.02 to 2 parts by weight, more preferably 0.05 to 1 part by weight. (B) If the compounding amount of the metal oxide is too small, dark color development is insufficient, and if it is too large, the mechanical strength and fluidity are lowered, which is not practical.

  In addition, if a metal oxide containing Mn is used as the metal oxide, the laser transmittance required for the resin composition for laser welding is lowered. Therefore, a metal oxide containing no Mn is used as the metal oxide. There is a need to.

(3) Filler In the present invention, (C) filler can be added in order to further improve characteristics such as heat resistance and mechanical strength. Specific examples of the filler (C) to be added include non-fibrous fillers such as fibrous or plate-like, scaly, granular, indeterminate, and crushed products. Specific examples include glass fiber and stainless steel. Fiber, metal fiber such as aluminum fiber and brass fiber, organic fiber such as aromatic polyamide fiber, gypsum fiber, ceramic fiber, asbestos fiber, zirconia fiber, alumina fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, rock wool, Alumina hydrate (whisker / plate), potassium titanate whisker, barium titanate whisker, aluminum borate whisker, silicon nitride whisker, talc, kaolin, silica (crushed / spherical), quartz, calcium carbonate, glass beads, glass Flakes, crushed and irregular glass, glass microballoons, glass -Molybdenum disulfide, wollastonite, aluminum oxide (crushed), titanium oxide (crushed), metal oxides such as zinc oxide, metal hydroxides such as aluminum hydroxide, aluminum nitride, calcium polyphosphate, graphite, metal Examples thereof include powder, metal flakes, metal ribbons, and metal oxides. Specific examples of metal species of metal powder, metal flakes, and metal ribbons include silver, nickel, copper, zinc, aluminum, stainless steel, iron, brass, chromium, and tin. In addition, fillers such as carbon powder, graphite, carbon flakes, scaly carbon, carbon nanotubes, PAN-based and pitch-based carbon fibers, mica, etc. lower the laser weldability, but mainly the thermoplastic colored resin composition of the present invention. It is possible to add a small amount so as not to impair the practical laser welding performance. The type of glass fiber or carbon fiber is not particularly limited as long as it is generally used for reinforcing a resin, and can be selected from long fiber type, short fiber type chopped strand, milled fiber, and the like.

  In the present invention, among the above fillers, (C1) a glass fiber having a single fiber diameter of 12 μm or more, and (C2) a non-fiber having an average particle diameter of 30 μm or more, from the infrared light transmission essential for laser weldability. A fibrous filler is preferred. Among these, glass fibers having a single fiber diameter of 15 μm or more and non-fibrous fillers having an average particle diameter of 50 μm or more are preferable. Further, the upper limit of the single fiber diameter of such glass fibers is preferably 35 μm or less from the viewpoint of a reinforcing material, and the upper limit of the average particle diameter of the non-fibrous filler is to avoid gate clogging troubles during molding. From the viewpoint, the upper limit is preferably 1000 μm or less. Moreover, it is preferable that it is a translucent filler, and as a material, specifically, E glass, C glass, H glass, alumina hydrate, translucent alumina, zinc oxide, translucent aluminum nitride, silica, Examples include natural quartz glass, synthetic quartz glass, metal hydroxides such as aluminum hydroxide, etc. The shape is fibrous or non-fibrous such as plate, scale, granular, indefinite shape, crushed product, etc. Is mentioned. The single fiber diameter is a value measured by a test method based on JIS-R3420 5,6. The average particle diameter is a number average obtained by a microtrack method in which ethanol is added to 0.70 g of a sample and ultrasonically dispersed for 3 minutes, and laser light is irradiated.

  Among the translucent fillers, those having a refractive index of 1.6 to 1.8, preferably 1.63 to 1.77 are particularly preferred from the viewpoint of laser transmittance, specifically H glass, alumina water. Japanese products are particularly preferred. The refractive index referred to here is measured on the basis of the critical angle of total reflection using a 10 mm-square cubic test piece having the same composition, using a pull refractometer.

  The filler can be used in combination of two or more in order to obtain a balance between mechanical strength and molded product warp. For example, glass fiber and mica or glass flake and alumina (aluminum oxide) (pulverized), Examples thereof include glass fibers and glass beads, silica and crushed glass, milled fibers and crushed glass.

  The surface of the filler used in the present invention can be used by treating the surface with a known coupling agent (for example, silane coupling agent, titanate coupling agent, etc.) or other surface treatment agents. .

  The blending amount of the filler (C) used in the present invention is 1 to 600 parts by weight with respect to 100 parts by weight of the thermoplastic resin (A) from the balance of laser weldability, heat resistance, mechanical strength, and the like. Preferably it is 5-100 weight part, More preferably, it is 10-70 weight part. (C) When the blending amount of the filler is too small, heat resistance and mechanical strength are insufficient, and when too large, the mechanical strength and fluidity are lowered, which is not practical.

(4) Antioxidant In the present invention, (D) an antioxidant can be added in order to suppress a decrease in laser transmittance due to oxidative coloring. (D) Specific examples of the antioxidant include calcium hypophosphite, 2,6-di-t-butyl-4-methylphenol, tetrakis (methylene-3- (3,5-di-t-butyl-4- Hydroxyphenyl) propionate) phenolic compounds such as methane, tris (3,5-di-t-butyl-4-hydroxybenzidine) isocyanurate, dilauryl-3,3′-thiodipropionate, dimyristyl-3,3 ′ -Sulfur compounds such as thiodipropionate, phosphorus compounds such as trisnonylphenyl phosphite, distearyl pentaerythritol diphosphite, and the like are mentioned, among which calcium hypophosphite is preferable. (D) The compounding quantity of antioxidant is 0.01-5 weight part normally with respect to 100 weight part of (A) component, Preferably it is 0.05-3 weight part, More preferably, it is 0.1-1 weight. Part.

  Moreover, in order to suppress the laser transmittance fall by oxidation coloring, the said antioxidant can also be used in combination of 2 or more types.

(5) Elastomer Furthermore, in order to improve the impact resistance and cold resistance of the resin composition for laser welding in the present invention, (E) an elastomer can be added. Examples of (E) elastomers include olefin elastomers, modified olefin elastomers, and styrene elastomers.

  Examples of olefin elastomers include (co) polymers obtained by polymerizing α-olefins alone or two or more of ethylene, propylene, butene-1, pentene-1, 4-methylpentene-1, isobutylene, and the like, α- Copolymers of olefins with α, β-unsaturated acids and alkyl esters thereof such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, etc. Etc. Specific examples of the olefin elastomer include polyethylene, polypropylene, ethylene / propylene copolymer (“/” represents copolymerization, hereinafter the same), ethylene / butene-1 copolymer, ethylene / methyl acrylate copolymer. Ethylene / ethyl acrylate copolymer, ethylene / butyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer, ethylene / butyl methacrylate copolymer, and the like.

  In order to further improve the impact resistance and cold heat resistance of the thermoplastic colored resin composition for laser welding, a modified olefin-based elastomer can be added. The modified olefin elastomer is obtained by introducing a monomer component (functional group-containing component) having a functional group such as an epoxy group, an acid anhydride group, or an ionomer into the above-described olefin elastomer. Examples of ingredients include maleic anhydride, itaconic anhydride, citraconic anhydride, endobicyclo [2.2.1] 5-heptene-2,3-dicarboxylic acid, endobicyclo- [2.2.1] 5- Monomers containing an acid anhydride group such as heptene-2,3-dicarboxylic acid anhydride, single monomers containing an epoxy group such as glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, glycidyl citraconic acid And monomers containing ionomers such as a monomer and a carboxylic acid metal complex.

  The method for introducing these functional group-containing components is not particularly limited, and the same olefinic (co) polymer as that used for the olefinic elastomer may be copolymerized when (co) polymerizing, or olefinic (co) A method such as graft introduction into the polymer using a radical initiator can be used. The amount of the functional group-containing component introduced is in the range of 0.001 to 40 mol%, preferably 0.01 to 35 mol%, based on all monomers constituting the modified olefinic (co) polymer. Is appropriate.

  Specific examples of the olefin (co) polymer obtained by introducing a monomer component having a functional group such as an epoxy group, an acid anhydride group, or an ionomer into a particularly useful olefin polymer include ethylene / propylene-g- Glycidyl methacrylate copolymer (“g” represents graft, the same applies hereinafter), ethylene / butene-1-g-glycidyl methacrylate copolymer, ethylene / glycidyl acrylate copolymer, ethylene / glycidyl methacrylate copolymer Polymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer, ethylene / methyl methacrylate / glycidyl methacrylate copolymer, ethylene / propylene-g-maleic anhydride copolymer, ethylene / butene-1-g-anhydrous Maleic acid copolymer, ethylene / methyl acrylate-g-maleic anhydride copolymer, Len / ethyl acrylate-g-maleic anhydride copolymer, ethylene / methyl methacrylate-g-maleic anhydride copolymer, ethylene / ethyl methacrylate-g-maleic anhydride copolymer, ethylene / methacrylic acid copolymer Examples thereof include a zinc complex of a polymer, a magnesium complex of an ethylene / methacrylic acid copolymer, and a sodium complex of an ethylene / methacrylic acid copolymer.

  Preferred are ethylene / glycidyl methacrylate copolymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer, ethylene / methyl methacrylate / glycidyl methacrylate copolymer, ethylene / butene-1-g-maleic anhydride. Examples thereof include an acid copolymer and an ethylene / ethyl acrylate-g-maleic anhydride copolymer.

  Particularly preferred are ethylene / glycidyl methacrylate copolymers, ethylene / methyl acrylate / glycidyl methacrylate copolymers, ethylene / methyl methacrylate / glycidyl methacrylate copolymers, and the like.

  On the other hand, specific examples of the styrene elastomer include styrene / butadiene copolymer, styrene / ethylene / butadiene copolymer, styrene / ethylene / propylene copolymer, styrene / isoprene copolymer, and the like. However, styrene / butadiene copolymers are preferred. More preferably, an epoxidized product of a styrene / butadiene copolymer is used.

  (E) The compounding quantity of an elastomer is 0.5-20 weight part normally with respect to (A) component, Preferably it is 0.8-10 weight part, More preferably, it is 1-6 weight part.

  In addition, the above elastomers can be used in combination of two or more in order to obtain a balance between impact resistance, cold resistance, and laser transmittance.

(6) Other additives In the thermoplastic coloring resin composition for laser welding in the present invention, other components such as silane compounds (epoxysilane compounds, aminosilane compounds, ureidosilane compounds, Isocyanate silane compounds, etc.), heat stabilizers (hindered phenols, hydroquinones, phosphites, etc.), weathering agents (resorcinols, salicylates, benzotriazoles, benzophenones, hindered amines, etc.), Release agents and lubricants (montanic acid and metal salts thereof, esters thereof, half esters thereof, stearyl alcohol, stearamide, various bisamides, bisureas and polyethylene waxes), pigments (cadmium sulfide, phthalocyanine, carbon black for coloring, etc.), dye (Nigrosine, etc.), crystal nucleating agents (talc, silica, kaolin, clay, polyether ether ketone, etc.), plasticizers (octyl p-oxybenzoate, N-butylbenzenesulfonamide, 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, etc.), flame retardants (eg red phosphorus) , Phosphates, melamine cyanurate, magnesium hydroxide, aluminum hydroxide and other hydroxides, ammonium polyphosphate, brominated polystyrene, brominated polyphenylene ether, brominated polycarbonate, brominated epoxy resins or their brominated flame retardants Combination with antimony trioxide, etc.), other It can be added to coalesce.

(7) Blending of each component The method for producing the laser colored thermoplastic colored resin composition of the present invention is usually produced by a known method. For example, (A) a thermoplastic resin, (B) a metal oxide, other necessary additives, and (D) an antioxidant are pre-mixed or supplied to an extruder or the like and sufficiently melt kneaded. To be prepared. Further, when (C) the filler is added, in order to suppress breakage of the fiber of the fibrous filler, preferably (A) a thermoplastic resin, (B) a metal oxide, other necessary additives and (D ) An antioxidant is introduced from the beginning of the extruder, and (C) filler is prepared by feeding to the extruder using a side feeder.

  When producing a thermoplastic colored resin composition for laser welding, for example, using a single-screw extruder, twin-screw, three-screw extruder, kneader type kneader or the like equipped with a “unimelt” (R) type screw. It can be melt-kneaded at ˜350 ° C. to make a composition.

(8) Molding / use of thermoplastic colored resin composition The laser colored thermoplastic colored resin composition of the present invention is generally used for injection molding, extrusion molding, compression molding, blow molding, injection compression molding, transfer molding, vacuum molding, etc. In general, the thermoplastic resin is molded by a known molding method, and injection molding is particularly preferable.

  The molded body thus obtained maintains both laser transparency and dark achromatic color, and further utilizes a molded article that is used by laser welding, preferably a laser beam, taking advantage of its low color fading in a high temperature environment. A practical composite molded body can be provided by being used for the molded body on the transmission side and laser welding with other members. For example, it is useful for electrical / electronic applications, automotive applications, general miscellaneous goods applications, building materials, etc. Specifically, electronic component cases such as personal computers, liquid crystal projectors, mobile devices, mobile phones, and switch modules, remote controllers Shielding against electromagnetic waves in internal communication parts, electrical parts module parts, engine compartment module parts, intake manifolds, underhood parts, radiator parts, cockpit module parts used in instrument panels, etc. Laser welding for parts such as installed antennas that are required or applications that require high dimensional accuracy, especially for automobile parts and electrical / electronic parts where metal replacement is eagerly desired for weight reduction. This is useful for molded products that have a dark achromatic color. From the design of the laser beam transmission side of the laser welding bonding resin molding for various applications achromatic dark system useful for a molded article to be desired. Since the laser welding resin composition of the present invention is excellent in laser beam transmission, a good adhesive force can be obtained even when the thickness of the laser beam transmission part of the welded portion by the laser beam is 5 mm or less. If it is 5 mm or less, further 2.5 mm or less, stronger adhesive force can be obtained. In order to obtain substantial strength and productivity of the molded body, the lower limit thickness is preferably 0.1 mm.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited by a following example.

(Reference Example) Production of PPS-1 A sodium sulfide nonahydrate 6.005 kg (25 mol), sodium acetate 0.787 kg (9.6 mol) and NMP 5 kg were charged into an autoclave equipped with a stirrer and gradually heated to 205 ° C. while introducing nitrogen. The temperature was raised and 3.6 liters of water was distilled off. Next, after cooling the reaction vessel to 180 ° C, 3.712 kg (25.25 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 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., it was dried under reduced pressure at 80 ° C. for 24 hours to obtain PPS-1 having a melting point of 278 ° C., a falling crystallization temperature of 180 ° C. and MFR of 100 g / 10 min. PPS-1 obtained by this method was subjected to the following Examples and Comparative Examples.

  The MFR was determined by drying 5 g of PPS resin powder at 130 ° C. for 3 hours and retaining the powder at 315.5 ° C. for 5 minutes, applying a 5 kg load (based on JIS-K7210).

(Thermoplastic resin used in Examples and Comparative Examples)
PA-1: Polyamide resin “Amilan” CM1010 (manufactured by Toray Industries, Inc.) Melting point 222 ° C., falling crystallization temperature 170 ° C.
PBT-1: Polybutylene terephthalate resin “Toraycon” 1100S (manufactured by Toray Industries, Inc.) Melting point 224 ° C.

(Coloring agents used in Examples and Comparative Examples)
Complex oxide pigment-1: Dipyroxide black # 9595 (manufactured by Dainichi Seika Kogyo Co., Ltd.), Fe—Cr complex oxide pigment, (Fe, Cr) ₂ O ₃
Complex oxide pigment-2: Dipyroxide black # 9590 (manufactured by Dainichi Seika Kogyo Co., Ltd.), Co—Cr—Fe complex oxide pigment, (Co, Fe) (Fe, Cr) ₂ O ₄
Complex oxide pigment-3: Black pigment D (manufactured by Toyo Ink Co., Ltd.), Fe—Cr complex oxide pigment, (Fe, Cr) ₂ O ₃
Complex oxide pigment-4: Cobalt oxide (manufactured by Dainichi Seika Kogyo Co., Ltd.), Co ₃ O ₄
Complex oxide pigment-5: Dipyroxide Blue # 9410 (manufactured by Dainichi Seika Kogyo Co., Ltd.), Co—Al complex oxide pigment, CoAl ₂ O ₄
Complex oxide pigment-6: Dipyroxide black # 95550 (manufactured by Dainichi Seika Kogyo Co., Ltd.), Cu—Fe—Mn complex oxide pigment, (Cu, Fe, Mn) (Fe, Mn) ₂ O ₄
Dye-1: anthraquinone red dye / anthraquinone blue dye / perinone orange dye = 2: 1: 2
Organic pigment-1: Monoazo red pigment Organic pigment-2: Monoazo green pigment CB-1: Carbon black

(Fillers used in Examples and Comparative Examples)
Glass fiber (GF1): T-747H (manufactured by Nippon Electric Glass Co., Ltd.) E glass, single fiber diameter 10.5 μm, refractive index (n _D ) 1.55
Glass fiber (GF2): T-187N (manufactured by NEC Corporation Glass Co.) E glass, monofilament diameter 17 .mu.m, the refractive index _(n D) 1.55
Glass fiber (GF3): T-747T (manufactured by Nippon Electric Glass Co., Ltd.) E glass, single fiber diameter 23 μm, refractive index (n _D ) 1.55
E glass pulverized product (EG-1): E glass (manufactured by Nippon Electric Glass Co., Ltd.) was pulverized with a Henschel mixer, sieved with a 63 μm pass, 9.5 μm undercut, and an average particle size of 20 μm (Microtrack method). EG was obtained. Refractive index (nD) 1.55
H glass pulverized product (HG-1): H glass (manufactured by Nippon Electric Glass Co., Ltd.) was pulverized with a Henschel mixer, sieved with a 63 μm pass, 9.5 μm undercut, and an average particle size of 20 μm (Microtrack method). HG1 was obtained. Refractive index (nD) 1.74

(Antioxidant used in Examples and Comparative Examples)
Antioxidant: “Calcium hypophosphite” (manufactured by Taihei Chemical Industrial Co., Ltd.)

Examples 1-24, Comparative Examples 1-6
PPS-1 produced in Reference Example, the above thermoplastic resin, colorant, filler and antioxidant were blended in the amounts shown in Tables 1 and 2 using a ribbon blender, and PCM30 with a 3-hole strand die head (biaxial extruder; Ikekai (Made by Steel) and melt kneaded at the resin temperatures shown in Tables 1 and 2 to obtain pellets. Next, after drying in a hot air oven at 130 ° C. for 4 hours, the following evaluation was performed. The results are shown in Tables 1 and 2.

(1) Melting point About 10 mg was collected from a thermoplastic resin pellet as a sample, and a melting point peak (endotherm) when heated at a rate of temperature increase of 20 ° C./min using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer. Peak) The temperature was measured and taken as the melting point.

(2) Temperature-falling crystallization temperature About 10 mg was sampled from a thermoplastic resin pellet as a sample, heated at a heating rate of 20 ° C./min using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer, Inc. at 340 ° C. After holding for 5 minutes, the temperature of the crystallization peak (exothermic peak) when the temperature was lowered at a rate of 20 ° C./minute was measured and taken as the temperature-falling crystallization temperature.

(3) Laser permeability evaluation Using an injection molding machine UH1000 (manufactured by Nissei Plastic Industry Co., Ltd.), the test piece shown in FIG. 1 was prepared at the resin temperature and mold temperature shown in Table 1. L shown here is 80 mm and D is 1 mm. For the measurement of transmittance, an ultraviolet near infrared spectrophotometer (UV-3100) manufactured by Shimadzu Corporation was used, and an integrating sphere was used for the detector. As an index of laser transmission, the transmittance at a wavelength of 940 nm in the near infrared was used as an index, and a transmittance of 10% or more optimum for laser welding was expressed as “◯” and less than 10% as “X”.

(4) Laser welding strength evaluation Using the test piece similar to the test piece used in the laser transmission evaluation, it was processed into the shape shown in FIG. Here, L is 70 mm, W is 24 mm, and D is 1 mm. As shown in FIGS. 3 and 4, the laser transmission sample and the laser absorption side sample were overlapped, the length L was 30 mm, the laser welding distance Y was 20 mm, laser welding was performed, and the tensile strength at break was measured.

  The welding conditions and welding strength measurement conditions are as follows.

  Laser welding conditions were used under the conditions that the best welding strength was obtained in the output 15 to 35 W range and the laser scanning speed 1 to 50 mm / sec using Leister's MODULAS C. The focal length was 38 mm and the focal diameter was fixed at 0.6 mm. In addition, a general tensile testing machine (AG-500B) was used to measure the welding strength, and both ends of the test piece were fixed, and a tensile test was performed so that a tensile shear stress was generated at the welding site. The tensile speed during strength measurement is 1 mm / min, and the span is 40 mm. The welding strength was defined as the breaking load per unit area of the weld fracture surface when the welded site was broken, and the area was calculated from the long side of the weld fracture surface and the width of the center. The thermoplastic resin composition of the present invention was used for the laser beam transmission sample, and a material obtained by further adding 0.4 parts of carbon black to the transmission side sample composition was used for the laser beam absorption side sample.

(5) Color tone evaluation Using a test piece similar to the test piece used in the laser transmission evaluation, a SM color computer (SM-5) manufactured by Suga Test Instruments Co., Ltd. was used to measure the color of the molded product. The measurement conditions were a C-light 2 degree field of view, a TM type 2 optical path anti-glare optical system, a 12 mm diameter sample stage, and a condensing lens for the sample stage. Note that L * (L value) is used as an index as to whether or not a dark color tone is manifested. When the L value is 70 or more (light color), “x” and the L value is 30 or more and less than 70 ( “O” for “gray” and “◎” for L value less than 30 (black).

(6) Color tone change evaluation Using a test piece similar to the molded product used in laser transmittance evaluation and color tone evaluation, high-temperature treatment at 150 ° C is performed for 24 hours, and color tone change from before the treatment is performed is made by Suga Test Instruments Co. Measurements were made using an SM color computer (SM-5). In addition, ΔE is used as an index of color tone change, and ΔE is described as “◯” when 5 or less and “×” when 5 or more.

(7) Evaluation of mold contamination The same test as the molded product used in laser permeability evaluation and color tone evaluation at the resin temperature and mold temperature shown in Table 1 using an injection molding machine UH1000 (manufactured by Nissei Plastic Industry Co., Ltd.) The pieces were continuously molded, and the contamination level when the mold surface and the gas vent after 500 shots were wiped with an alcohol solvent was visually observed. Light contamination was marked with “◯”, and marked contamination was marked with “x”.

  As described above, the colored resin composition for laser welding according to the present invention has a dark color tone with excellent heat resistance while maintaining good laser transmittance, and thus obtains a molded article with extremely excellent laser weldability. It is useful for laser welding of resin molded products for various uses such as electrical / electronic related equipment, precision machinery related equipment, office equipment, automobile / vehicle related parts, building materials, packaging materials, furniture, daily goods, etc. However, the application range is not limited to these.

(A) is a top view of the test piece for laser permeability, color tone, color tone change, mold contamination evaluation used in the examples, and (b) is a side view of the test piece. (A) is a top view of the laser welding test piece used in the Example, (b) is a side view of the test piece. It is the schematic which shows the outline of the laser welding method. (A) is a top view of the test piece for laser welding strength measurement used in the Example, (b) is a side view of the test piece.

Explanation of symbols

1. Sprue 2. Runner 3. Gate 4. 4. Test piece for evaluation Measurement site 6. 6. Laser welding test piece Laser light irradiation unit 8. Laser light9. 9. Laser beam trajectory Laser transmission side sample 11. Laser absorption side sample 12. Laser welding part 13. Test piece for laser welding strength measurement

Claims (10)

(A) A thermoplastic colored resin composition for laser welding, comprising 0.01 to 5 parts by weight of (B) a metal oxide not containing Mn with respect to 100 parts by weight of a thermoplastic resin. (B) The thermoplastic colored resin composition for laser welding according to claim 1, wherein the metal oxide not containing Mn contains an oxide of at least one metal selected from Fe, Cr, Co and Al. (B) The metal oxide not containing Mn is at least one selected from cobalt oxide, Co—Al composite oxide, Cr—Fe composite oxide, and Co—Cr—Fe composite oxide. Thermoplastic coloring resin composition for laser welding. (A) The thermoplastic colored resin composition for laser welding according to claim 1, wherein the thermoplastic resin is a crystalline resin having a melting point of 220 ° C. or higher. (A) The thermoplastic colored resin composition for laser welding according to any one of claims 1 to 4, wherein the thermoplastic resin is a polyphenylene sulfide resin having a temperature drop crystallization temperature of 205 ° C or lower. (A) One or more types selected from (C1) glass fiber having a single fiber diameter of 12 μm or more and (C2) a non-fibrous filler having an average particle diameter of 30 μm or more with respect to 100 parts by weight of the thermoplastic resin. (C) The thermoplastic colored resin composition for laser welding according to any one of claims 1 to 5, comprising 1 to 600 parts by weight of filler. (C) The thermoplastic coloring resin composition for laser welding according to claim 6, wherein the refractive index of the filler is 1.6 to 1.8. The laser colored thermoplastic colored resin composition according to any one of claims 1 to 7, further comprising (D) an antioxidant in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the (A) thermoplastic resin. object. A laser welded molded article comprising the thermoplastic colored resin composition for laser welding according to any one of claims 1 to 8, wherein the thickness of the welded portion is 5 mm or less. Molded body. A composite molded article obtained by laser welding a molded article comprising the colored resin composition for laser welding according to claim 1.

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