Resin composition, molded article, application of resin composition, kit, laser-welded article, and method for manufacturing laser-welded article

Abstract

Provided are a resin composition used as a laser-transmitting resin member at the time of laser welding and capable of laser marking, a molded article using the aforementioned resin composition, an application of the resin composition, a kit, a laser-welded article, and a method for manufacturing a laser-welded article. A resin composition used as a laser-transmitting resin member at the time of laser welding and capable of laser marking, the resin composition comprising, relative to 100 parts by mass of a thermoplastic polyester resin: 5 to 100 parts by mass of a butadiene rubber-containing polystyrene, and 0.01 to 5 parts by mass of an infrared-transmitting colorant.

Description

Technical Field

[0001] This invention relates to: a resin composition used as a laser-transmitting resin component in laser welding and capable of laser marking, as well as molded articles using the aforementioned resin composition, applications of the resin composition, kits, laser-welded articles, and methods for manufacturing laser-welded articles. Background Technology

[0002] Thermoplastic polyester resins, represented by polybutylene terephthalate resin, have excellent mechanical strength, chemical resistance, and electrical insulation. In addition, they have excellent heat resistance, moldability, and reusability. Therefore, they are widely used in various equipment components.

[0003] Recently, there has been an increase in examples of welding processes performed to improve productivity, most of which employ laser welding, which has minimal impact on electronic components (e.g., Patent Document 1).

[0004] Laser welding is a technique in which a laser-transmitting resin component (hereinafter, sometimes referred to as a "transmitting resin component") made of a laser-transmitting material is overlapped with a laser-absorbing resin component (hereinafter, sometimes referred to as a "absorbing resin component") made of a laser-absorbing material. A laser beam is irradiated from the transmitting resin component side, and the interface between the transmitting and absorbing resin components is heated, thus welding occurs. Furthermore, the resin composition used in the molded article for this application is required to have the property of being weldable by laser beam irradiation (laser weldability).

[0005] On the other hand, in molded products, product information is often printed or depicted on the surface to facilitate design, information display, and component identification during assembly. Furthermore, to ensure visibility over extended periods, laser marking is sometimes used from a reliability standpoint.

[0006] Furthermore, in recent years, resin compositions that can be used as laser-transmitting resin components during laser welding and resin compositions that can be laser-marked have also been studied (Patent Document 2).

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent No. 6183822

[0010] Patent Document 2: Japanese Patent Application Publication No. 2020-50822 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] Here, in laser welding, the following operations are performed: in order to maximize the transmittance of the laser beam and make the resin component transparent, conversely, in order to increase the absorption rate of the laser beam, the resin component that absorbs the laser beam is colored with pigments or the like.

[0013] However, from a design perspective, it is preferable that the resin-transmitting component is also colored in a similar color to the resin-absorbing component, for example, sometimes both the resin-absorbing component and the resin-transmitting component are colored black.

[0014] However, for resin-transmitting components, similar to resin-absorbing components, when colored with pigments that have a high absorptivity to the laser beam, the laser beam no longer passes through, making laser welding impossible. Therefore, pigments that do not impede the transmission of the laser beam are used in the coloring of resin-transmitting components.

[0015] On the other hand, when laser marking is applied to a resin component, marking cannot be performed when the laser beam passes through. Therefore, a resin composition is sought that allows the laser beam to pass through to a certain extent while still enabling laser marking.

[0016] The object of the present invention is to solve the above-mentioned problems, and its object is to provide: a resin composition that can be used as a laser-transmitting resin component in laser welding and can be laser-marked, a molded article using the aforementioned resin composition, an application of the resin composition, a kit, a laser-welded article, and a method for manufacturing the laser-welded article.

[0017] Solution for solving the problem

[0018] Based on the above research, it was found that by blending polystyrene containing butadiene rubber and infrared-transmitting colorants into thermoplastic polyester resin, both laser transmittance and laser marking properties can be achieved.

[0019] Specifically, the above-mentioned problems were solved according to the following solution.

[0020] <1> A resin composition for use as a laser-transmitting resin component in laser welding and for laser marking, wherein the resin composition comprises, relative to 100 parts by weight of thermoplastic polyester resin, 5 to 100 parts by weight of polystyrene containing butadiene rubber and 0.01 to 5 parts by weight of an infrared-transmitting colorant.

[0021] <2> according to <1> The resin composition wherein the aforementioned thermoplastic polyester resin comprises polybutylene terephthalate resin.

[0022] <3> according to <1> or <2> The resin composition further comprises, relative to 100 parts by weight of thermoplastic polyester resin, 1 to 100 parts by weight of polycarbonate resin.

[0023] <4> according to <3> The resin composition comprises, relative to 100 parts by weight of the aforementioned butadiene-containing polystyrene, 1 to 500 parts by weight of polycarbonate resin.

[0024] <5> according to <1> ~ <4> The resin composition described in any one of the following statements, wherein the aforementioned butadiene rubber-containing polystyrene is high-impact polystyrene (HIPS).

[0025] <6> according to <1> ~ <5> The resin composition described in any one of the following examples further comprises an epoxy compound.

[0026] <7> according to <1> ~ <6> The resin composition described in any one of the following examples further comprises an inorganic filler.

[0027] <8> according to <1> ~ <7> The resin composition described in any one of the above statements further comprises a phosphorus-based stabilizer.

[0028] <9> according to <1> ~ <8> The resin composition according to any one of the following methods, wherein the aforementioned infrared-transmitting colorant is an infrared-transmitting dye.

[0029] <10> according to <1> ~ <9> The resin composition according to any one of the above-mentioned infrared-transmitting colorants contains: a black dye and / or a black dye composition containing two or more colored dyes.

[0030] <11> according to <10> The resin composition, wherein the resin composition can be laser-marked with a hue brighter than that of the aforementioned black dye and / or black dye composition.

[0031] <12> according to <1> ~ <11> The resin composition according to any one of the above-mentioned infrared-transmitting colorants, wherein the nickel content in the aforementioned infrared-transmitting colorant is less than 0.8% by mass.

[0032] <13> according to <1> ~ <12> The resin composition according to any one of the following methods, wherein the content of pigment other than infrared-transmitting colorant in the aforementioned resin composition is less than 1% by mass of the content of the aforementioned infrared-transmitting colorant.

[0033] <14> according to <1> ~ <13> The resin composition according to any one of the following methods, wherein the content of aniline black in the aforementioned resin composition is less than 1% by mass of the content of the aforementioned infrared transmitting colorant.

[0034] <15> according to <1> ~ <14> The resin composition according to any one of the following methods, wherein the transmittance at a wavelength of 1064 nm is 12% or more when the aforementioned resin composition is molded into a test piece with a thickness of 1.5 mm.

[0035] <16> according to <1> ~ <15> The resin composition according to any one of the following methods, wherein when the aforementioned resin composition is molded to a thickness of 1.5 mm and a portion is laser-marked, the color difference ΔE between the hue of the laser-marked portion and the hue of the non-laser-marked portion based on the SCE method is 10.0 or more.

[0036] <17> A molded article is formed by molding a composition comprising a thermoplastic polyester resin and an infrared-transmitting colorant.

[0037] The light transmittance of the molded article at a wavelength of 1064nm is above 12%.

[0038] When laser marking is performed, the color difference ΔE between the hue of the laser-marked area and the hue of the non-laser-marked area based on the SCE method is 7.0 or higher.

[0039] <18> A molded product, which is made from <1> ~ <16> The resin composition described in any one of the above statements is formed.

[0040] <19> according to <17> or <18> The molded article has been laser-marked.

[0041] <20> <1> ~ <16> The resin composition described in any one of the following is used as a laser-transmitting resin component during laser welding and in a resin component capable of laser marking.

[0042] <21> A reagent kit having:

[0043] <1> ~ <16> The resin composition described in any one of the following; and,

[0044] A light-absorbing resin composition comprising a thermoplastic resin and a light-absorbing pigment.

[0045] <22> according to <21> The kit wherein the aforementioned resin composition and the aforementioned light-absorbing resin composition are respectively molded to a thickness of 1.5 mm, and the difference in hue L based on the SCE method, i.e., ΔE, is less than 6.0.

[0046] <23> A laser-welded product, which is made of <1> ~ <16> Laser-welded articles comprising a laser-transmitting resin component formed from any one of the resin compositions and a laser-absorbing resin component formed from a light-absorbing resin composition comprising a thermoplastic resin and a light-absorbing pigment.

[0047] <24> according to <23> The laser-welded product is capable of laser marking on the aforementioned laser-transmitted resin component.

[0048] <25> according to <23> The laser-welded product has laser-marked the aforementioned laser-transmitting resin component.

[0049] <26> A method for manufacturing laser-welded articles, comprising the following steps:

[0050] To <1> ~ <16> The laser formed by the resin composition described in any one of the above statements is irradiated through the resin component to perform laser marking; and,

[0051] The aforementioned laser-transmitting resin component is laser-welded to a laser-absorbing resin component formed from a light-absorbing resin composition comprising thermoplastic resin and light-absorbing pigment.

[0052] <27> according to <26> The method for manufacturing the laser-welded article, wherein the aforementioned laser welding is performed using current scanning laser welding.

[0053] The effects of the invention

[0054] According to the present invention, the following can be provided: a resin composition that can be used as a laser-transmitting resin component in laser welding and is capable of laser marking; a molded article using the aforementioned resin composition; a kit; an application of the resin composition; a laser-welded article; and a method for manufacturing the laser-welded article. Attached Figure Description

[0055] Figure 1 A schematic diagram is shown of a test piece (through resin component I) used to determine the laser welding strength of an embodiment.

[0056] Figure 2 A schematic diagram is shown of the test piece (absorbing resin component II) used to determine the laser welding strength of the embodiment.

[0057] Figure 3 This is a schematic diagram of a test piece (a combination of a resin-transmitting component I and an absorbent resin component II) used to determine the laser welding strength of an embodiment.

[0058] Figure 4 A schematic diagram illustrating the laser welding strength measurement method of an embodiment. Detailed Implementation

[0059] Hereinafter, a method for implementing the present invention (hereinafter referred to as "this embodiment") will be described in detail. It should be noted that the following embodiment is an example for illustrating the present invention, and the present invention is not limited to this embodiment.

[0060] It should be noted that in this specification, “~” is used to include the values ​​recorded before and after it as the lower limit and upper limit values.

[0061] Unless otherwise specified, all physical properties and characteristic values ​​in this manual are those taken at 23°C.

[0062] The resin composition of this embodiment is characterized in that it is a resin composition that can be used as a laser-transmitting resin component during laser welding and is capable of laser marking. The resin composition comprises, relative to 100 parts by weight of thermoplastic polyester resin, 5 to 100 parts by weight of polystyrene containing butadiene rubber and 0.01 to 5 parts by weight of an infrared-transmitting colorant. By forming this configuration, a resin composition that can be used as a laser-transmitting resin component during laser welding and is capable of laser marking can be formed.

[0063] Furthermore, the resin composition of this embodiment exhibits a large color difference between the transmissive resin component and its laser marking portion, enabling excellent laser marking. Additionally, the transmissive resin component formed from the resin composition of this embodiment has high transmittance of light with a wavelength of 1060 nm, resulting in excellent laser transmittance. Moreover, the aforementioned transmissive resin component maintains high strength even after an autoclave test. Furthermore, the molded article (transmissive resin component) formed from the resin composition of this embodiment also exhibits a small color difference between the molded article (transmissive resin component) and the absorbing resin component, allowing for excellent design flexibility. Furthermore, the color difference between the laser marking portion of the transmissive resin component and the absorbing resin component can be increased.

[0064] If conventional laser marking agents (such as carbon black) are blended into thermoplastic polyester resin, light becomes impermeable, making it difficult to use as a transmissive resin composition (transmissive resin component) for laser welding. On the other hand, if a colorant that easily transmits laser light (e.g., light with a wavelength of 1060 nm) is blended in, a resin composition with excellent designability and capable of laser welding can be formed, but laser marking becomes difficult. In this embodiment, designability is ensured by blending an infrared-transmitting colorant into the thermoplastic polyester resin, and a polystyrene containing butadiene rubber is blended in, thereby forming a resin composition that can be both laser-marked and laser-welded.

[0065] The embodiments of the present invention will be described below.

[0066] <Thermoplastic polyester resin>

[0067] The resin composition of this embodiment comprises a thermoplastic polyester resin (hereinafter, sometimes simply referred to as "polyester resin").

[0068] The polyester resin used in this embodiment is not particularly limited in type; examples include polybutylene terephthalate resin and polyethylene terephthalate resin, with polybutylene terephthalate resin being preferred.

[0069] Polybutylene terephthalate resin is obtained by polycondensation of terephthalic acid, the main acid component, and 1,4-butanediol, the main glycol component. Terephthalic acid as the main acid component means that 50% or more by mass of the acid component is terephthalic acid, preferably 60% or more by mass, more preferably 70% or more by mass, and can be 80% or more by mass, 90% or more by mass, or 95% or more by mass. 1,4-Butanediol as the main glycol component means that 50% or more by mass of the glycol component is 1,4-butanediol, preferably 60% or more by mass, more preferably 70% or more by mass, and can be 80% or more by mass, 90% or more by mass, or 95% or more by mass.

[0070] When polybutylene terephthalate resin contains other acid components, examples include isophthalic acid and dimer acid. Additionally, when polybutylene terephthalate resin contains other glycol components, examples include polybutylene glycol (PTMG) and other polyalkylene glycols.

[0071] When using polybutylene terephthalate resin that is copolymerized from polybutanediol, the butylene glycol content in the copolymer is preferably 3 to 40% by mass, more preferably 5 to 30% by mass, and even more preferably 10 to 25% by mass. Setting this copolymerization ratio tends to result in a better balance between laser weldability and heat resistance, which is preferable.

[0072] When using a dimer acid copolymer of polybutylene terephthalate (PET) as the PET resin, the dimer acid component, based on carboxylic acid groups, preferably comprises 0.5 to 30 mol%, more preferably 1 to 20 mol%, and even more preferably 3 to 15 mol%. This copolymerization ratio tends to result in an excellent balance of laser weldability, long-term heat resistance, and toughness, which is preferable.

[0073] When using isophthalic acid copolymerized polybutylene terephthalate as the polybutylene terephthalate resin, the isophthalic acid component accounts for a preferred 1 to 30 mol% of the total carboxylic acid component, more preferably 1 to 20 mol%, and even more preferably 3 to 15 mol%, based on carboxylic acid groups. This copolymerization ratio tends to result in an excellent balance of laser weldability, heat resistance, injection molding properties, and toughness, which is preferable.

[0074] The polybutylene terephthalate resin used in this embodiment is preferably a resin (polybutylene terephthalate homopolymer) in which 90% or more by mass of the acid component is terephthalic acid and 90% or more by mass of the glycol component is 1,4-butanediol, or a copolymerized polybutylene terephthalate resin copolymerized with polybutanediol, or an isophthalic acid copolymerized polybutylene terephthalate resin.

[0075] The intrinsic viscosity of polybutylene terephthalate resin is preferably 0.5 to 2 dL / g. From the perspective of moldability and mechanical properties, an intrinsic viscosity in the range of 0.6 to 1.5 dL / g is more preferred. Using an intrinsic viscosity of 0.5 dL / g or higher tends to further improve the mechanical strength of the resulting molded article. Furthermore, using an intrinsic viscosity of 2 dL / g or less tends to further improve the flowability, moldability, and laser weldability of the polybutylene terephthalate resin.

[0076] It should be noted that the intrinsic viscosity is a value measured at 30°C in a 1:1 (mass ratio) mixture of tetrachloroethane and phenol.

[0077] When two or more polybutylene terephthalate resins are contained, the intrinsic viscosity is denoted as the intrinsic viscosity of the mixture.

[0078] The amount of terminal carboxyl groups in polybutylene terephthalate resin can be appropriately selected and determined, typically 60 eq / ton or less, preferably 50 eq / ton or less, and more preferably 30 eq / ton or less. By keeping the amount of terminal carboxyl groups below 50 eq / ton, gas generation during melt molding of polybutylene terephthalate resin can be more effectively suppressed. Furthermore, the lower limit of the amount of terminal carboxyl groups is not particularly limited, and is typically 5 eq / ton.

[0079] When two or more polybutylene terephthalate resins are contained, the amount of terminal carboxyl groups is recorded as the amount of terminal carboxyl groups in the mixture.

[0080] It should be noted that the amount of terminal carboxyl groups in polybutylene terephthalate resin is determined as follows: 0.5 g of polybutylene terephthalate resin is dissolved in 25 mL of benzyl alcohol, and titrated with a 0.01 mol / L benzyl alcohol solution containing sodium hydroxide. Methods for adjusting the amount of terminal carboxyl groups include any conventionally known methods such as adjusting the polymerization conditions (e.g., raw material ratio, polymerization temperature, reduced pressure method) or reacting the end-capping agent.

[0081] The polyethylene terephthalate resin used in this embodiment is a resin obtained by polycondensation of terephthalic acid, the main acid component, and ethylene glycol, the main glycol component. Terephthalic acid as the main acid component means that 50% or more by mass of the acid component is terephthalic acid, preferably 60% or more by mass, more preferably 70% or more by mass, and can be 80% or more by mass, 90% or more by mass, or 95% or more by mass. Ethylene glycol as the main glycol component means that 50% or more by mass of the glycol component is ethylene glycol, preferably 60% or more by mass, more preferably 70% or more by mass, and can be 80% or more by mass, 90% or more by mass, or 95% or more by mass.

[0082] When polyethylene terephthalate resin contains other acid components, examples of such other acid components include phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, 1,3-phenylene dioxydiacetic acid and their structural isomers, malonic acid, succinic acid, adipic acid and other dicarboxylic acids and their derivatives, p-hydroxybenzoic acid, glycolic acid and other hydroxy acids or their derivatives.

[0083] In addition, when polyethylene terephthalate resin contains other diol components, examples of such other diol components include aliphatic diols such as 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, pentamethylenediol, hexamethylenediol, and neopentyl glycol, alicyclic diols such as cyclohexanediol, and aromatic dihydroxy compound derivatives such as bisphenol A and bisphenol S.

[0084] Furthermore, the polyethylene terephthalate resin can be copolymerized with a branched component, such as a trifunctional acid with esterification ability, such as pyromellitic acid, trimellitic acid, or trimellitic acid, or a tetrafunctional alcohol with esterification ability, such as glycerol, trimethylolpropane, or pentaerythritol, in an amount of 1.0 mol% or less, preferably 0.5 mol% or less, and more preferably 0.3 mol% or less.

[0085] The intrinsic viscosity of polyethylene terephthalate resin is preferably 0.3 to 1.5 dL / g, more preferably 0.3 to 1.2 dL / g, and even more preferably 0.4 to 0.8 dL / g.

[0086] It should be noted that the intrinsic viscosity of polyethylene terephthalate resin is a value measured at 30°C in a 1:1 (mass ratio) mixture of tetrachloroethane and phenol.

[0087] Furthermore, the concentration of terminal carboxyl groups in the polyethylene terephthalate resin is preferably 3 to 60 eq / ton, more preferably 5 to 50 eq / ton, and even more preferably 8 to 40 eq / ton. By setting the terminal carboxyl group concentration to 60 eq / ton or less, the resin material tends to generate less gas during melt molding, resulting in improved mechanical properties of the molded article. Conversely, by setting the terminal carboxyl group concentration to 3 eq / ton or more, the heat resistance, retention heat stability, and color of the molded article tend to be improved, which is preferable.

[0088] It should be noted that the concentration of the terminal carboxyl groups of polyethylene terephthalate resin is calculated as follows: 0.5 g of polyethylene terephthalate resin is dissolved in 25 mL of benzyl alcohol, and titrated with a 0.01 mol / L benzyl alcohol solution of sodium hydroxide.

[0089] In this embodiment, the content of polyester resin (preferably polybutylene terephthalate resin) in the resin composition is preferably 25% by mass or more, more preferably 30% by mass or more, and even more preferably 35% by mass or more. By setting it to the aforementioned lower limit or above, there is a tendency to further improve the weld strength of the molded article. Furthermore, the content of the aforementioned polyester resin (preferably polybutylene terephthalate resin) in the resin composition is preferably 75% by mass or less, more preferably 65% ​​by mass or less, even more preferably 55% by mass or less, and even more preferably 45% by mass or less. By setting it to the aforementioned upper limit or less, there is a tendency to further improve the laser marking properties.

[0090] The resin composition of this embodiment may contain only one type or two or more types of polyester resin. When two or more types are contained, the total amount is preferably within the range described above.

[0091] <Polystyrene containing butadiene rubber>

[0092] The resin composition of this embodiment contains 5 to 100 parts by weight of butadiene rubber-containing polystyrene relative to 100 parts by weight of thermoplastic polyester resin. By including butadiene rubber-containing polystyrene, laser weldability is maintained and laser marking properties are improved. It is presumed that the butadiene portion functions as a laser marking agent.

[0093] The butadiene rubber content (butadiene rubber percentage) in polystyrene containing butadiene rubber is preferably 2.0% by mass or more, more preferably 3.0% by mass or more, even more preferably 4.0% by mass or more, further preferably 5.0% by mass or more, and even more preferably 6.0% by mass or more. By setting it to the aforementioned lower limit or above, there is a tendency to further improve the laser marking properties. In addition, the aforementioned butadiene rubber content is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, even more preferably 12.5% ​​by mass or less, further preferably 10.0% by mass or less, and even more preferably 8.5% by mass or less. By setting it to the aforementioned upper limit or less, there is a tendency to improve the laser beam transmittance and further improve the weldability.

[0094] Furthermore, the styrene content in the butadiene rubber-containing polystyrene is preferably 40% by mass or more, more preferably 45% by mass or more, further preferably more than 50% by mass, even more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more. Additionally, the styrene content in the butadiene rubber-containing polystyrene is preferably 97% by mass or less, and can be 95% by mass or less.

[0095] Furthermore, in this embodiment, the total content of butadiene rubber and styrene in the butadiene-containing polystyrene preferably accounts for 80% or more by mass, more preferably 85% or more by mass, and even more preferably 90% or more by mass, and can be 95% or more by mass. By setting it in this way, there is a tendency to further improve the laser marking properties of the resin composition.

[0096] It should be noted that the butadiene rubber in polystyrene containing butadiene rubber refers to butadiene rubber units, and the styrene in polystyrene containing butadiene rubber refers to styrene units.

[0097] The mass-average molecular weight of the polystyrene containing butadiene rubber is preferably 50,000 or more, more preferably 80,000 or more, even more preferably 100,000 or more, and still more preferably 120,000 or more, and even more preferably 150,000 or more. By setting it to the aforementioned lower limit or above, there is a tendency to further improve the mechanical strength of the molded article. In addition, the mass-average molecular weight of the aforementioned butadiene rubber is preferably 1,000,000 or less, more preferably 800,000 or less, even more preferably 500,000 or less, even more preferably 300,000 or less, and even more preferably 250,000 or less. By setting it to the aforementioned upper limit or below, there is a tendency to improve the fluidity during molding and further improve the moldability.

[0098] Examples of butadiene-containing polystyrene used in this embodiment include high-impact polystyrene (HIPS) and ABS resin, with HIPS being particularly preferred. HIPS comprises a graft copolymer obtained by grafting styrene monomers into a dry polymer of polybutadiene or a styrene-butadiene random copolymer. By using HIPS, there is a tendency for further improvement in laser marking properties.

[0099] In this embodiment, the butadiene-containing polystyrene content in the resin composition is 5 parts by weight or more, preferably 10 parts by weight or more, more preferably 20 parts by weight or more, further preferably 30 parts by weight or more, even more preferably 40 parts by weight or more, and even more preferably 45 parts by weight or more, relative to 100 parts by weight of thermoplastic polyester resin. By setting this to the aforementioned lower limit or above, there is a tendency to further improve the laser marking properties. Furthermore, the aforementioned butadiene-containing polystyrene content is 100 parts by weight or less, preferably 90 parts by weight or less, more preferably 80 parts by weight or less, even more preferably 70 parts by weight or less, even more preferably 60 parts by weight or less, and even more preferably 55 parts by weight or less, relative to 100 parts by weight of thermoplastic polyester resin. By setting this to the aforementioned upper limit or below, there is a tendency to further improve the weld strength.

[0100] The resin composition of this embodiment may contain only one type, or it may contain two or more types of butadiene-containing polystyrene. When two or more types are contained, the total amount is preferably within the range described above.

[0101] <Polycarbonate resin>

[0102] The resin composition of this embodiment may or may not contain polycarbonate resin. When the resin composition of this embodiment contains polycarbonate resin, it preferably contains 1 to 100 parts by weight relative to 100 parts by weight of thermoplastic polyester resin. By blending polycarbonate resin, laser beam transmittance and weldability can be improved.

[0103] The polycarbonate resin used in this embodiment can be any known polycarbonate resin. Polycarbonate resin is typically a branched thermoplastic polymer or copolymer obtained by reacting a dihydroxy compound or a small amount of a polyhydroxy compound with a carbonate or diester. The manufacturing method of the polycarbonate resin is not particularly limited; it can be manufactured using conventionally known methods such as the carbonate process (interfacial polymerization) or the melt process (transesterification). However, polycarbonate resins manufactured by melt polymerization are preferred from the perspective of laser transmittance and laser weldability.

[0104] The dihydroxy compound used as a starting material is preferably an aromatic dihydroxy compound, such as 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), tetramethylbisphenol A, bis(4-hydroxyphenyl)-p-diisopropylbenzene, hydroquinone, resorcinol, 4,4-dihydroxydiphenyl, etc., with bisphenol A being the most preferred. Alternatively, compounds obtained by bonding one or more tetraalkylphosphonium sulfonate ions to the above-mentioned aromatic dihydroxy compound may also be used.

[0105] Of the above-mentioned polycarbonate resins, aromatic polycarbonate resins derived from 2,2-bis(4-hydroxyphenyl)propane are preferred, as are aromatic polycarbonate copolymers derived from 2,2-bis(4-hydroxyphenyl)propane and other aromatic dihydroxy compounds. Alternatively, copolymers with polymers or oligomers having a siloxane structure may be used. Furthermore, two or more of the above-mentioned polycarbonate resins may be mixed for use.

[0106] The viscosity-average molecular weight of the polycarbonate resin is preferably 5,000 to 30,000, more preferably 10,000 to 28,000, and even more preferably 14,000 to 24,000. Using a viscosity-average molecular weight of 5,000 or higher tends to further improve the mechanical strength of the resulting molded article. Furthermore, using a viscosity-average molecular weight of 30,000 or less tends to further improve the flowability, moldability, and laser weldability of the resin composition.

[0107] It should be noted that the viscosity-average molecular weight of polycarbonate resin is calculated based on the viscosity of the solution measured at 25°C using dichloromethane as a solvent [Mv].

[0108] The content of polycarbonate resin in the resin composition of this embodiment, relative to 100 parts by weight of thermoplastic polyester resin, is preferably 1.0 part by weight or more, more preferably 5.0 parts by weight or more, even more preferably 7.5 parts by weight or more, further preferably 10.0 parts by weight or more, and even more preferably 15.0 parts by weight or more. By setting it to the aforementioned lower limit or above, there is a tendency to improve laser transmittance and enable welding with lower laser beam energy. In addition, the aforementioned content of polycarbonate resin, relative to 100 parts by weight of thermoplastic polyester resin, is preferably 100 parts by weight or less, more preferably 80.0 parts by weight or less, even more preferably 60.0 parts by weight or less, further preferably 45.0 parts by weight or less, and even more preferably 35.0 parts by weight or less. By setting it to the aforementioned upper limit or below, there is a tendency to further improve the laser welding strength.

[0109] The content of polycarbonate resin in the resin composition of this embodiment is preferably 1 part by weight or more, more preferably 5 parts by weight or more, further preferably 10 parts by weight or more, even more preferably 15 parts by weight or more, and even more preferably 20 parts by weight or more, relative to 100 parts by weight of polystyrene containing butadiene rubber. By setting it to the aforementioned lower limit or above, there is a tendency to improve laser beam transmittance and enable welding with lower laser beam energy. In addition, the aforementioned content of polycarbonate resin is preferably 500 parts by weight or less, more preferably 400 parts by weight or less, even more preferably 200 parts by weight or less, even more preferably 150 parts by weight or less, and even more preferably 75 parts by weight or less, relative to 100 parts by weight of polystyrene containing butadiene rubber. By setting it to the aforementioned upper limit or below, there is a tendency to further improve laser marking properties.

[0110] The resin composition of this embodiment may contain only one type of polycarbonate resin, or it may contain two or more types of polycarbonate resin. When two or more types are contained, the total amount is preferably within the range described above.

[0111] <Infrared Transmitting Colorant>

[0112] The resin composition of this embodiment contains 0.01 to 5 parts by weight of an infrared-transmitting colorant relative to 100 parts by weight of the thermoplastic polyester resin. By including the infrared-transmitting colorant, laser welding and laser marking can be achieved. In particular, laser welding and laser marking can be achieved using general laser irradiation conditions.

[0113] There are no particular limitations on infrared-transmitting colorants, as long as they allow a certain percentage or more of the laser light used for laser welding to pass through. Known colorants can be used. For example, colorants that allow at least 20% or more of light with wavelengths between 900 and 1100 nm to pass through are acceptable.

[0114] Infrared transmitting colorant refers to, for example, the following colorant: 30% by mass of polybutylene terephthalate resin (e.g., Novaduran (registered trademark) 5008), glass fiber (e.g., manufactured by Nippon Electric Glass Co., Ltd., trade name: T-127), and 0.2% by mass of colorant (considered to be an infrared transmitting colorant) are mixed in such a total that the transmittance is 12% or more when the transmittance is measured by the measurement method described in the examples below.

[0115] Furthermore, by incorporating the translucent colorant in this embodiment, the transmittance at a wavelength of 1064 nm when the resin composition of this embodiment is molded to a thickness of 1.5 mm can be, for example, 12% or more, and further 20% or more. As an upper limit, 100% is ideal, but it can also be 90% or less.

[0116] In this embodiment, the infrared-transmitting colorant is preferably an infrared-transmitting dye to improve the transmittance of the molded article.

[0117] The infrared-transmitting colorant can be selected appropriately according to its application, and its color is not particularly limited. The colorant used in this embodiment is preferably a black colorant (preferably a black dye), and / or a black colorant composition (preferably a black dye composition) containing two or more colored colorants (preferably colored dyes). More specifically, a black colorant composition refers to a colorant composition that combines two or more colored colorants such as red, blue, and green to produce a black color.

[0118] A first embodiment of the black colorant composition comprises a green colorant and a red colorant. A second embodiment of the black colorant composition comprises a red colorant, a blue colorant, and a yellow colorant.

[0119] Specific examples of infrared-transmitting colorants include aniline black, naphthalene phthalocyanine, aniline black, phthalocyanine, porphyrin, violet ketone, tetranaphthalene-triphenylene oxide, azo, azomethyl, anthraquinone, pyrazolone, dihydroxycyclobutenedione derivatives, perylene, chromium complexes, and imines, with azomethyl, anthraquinone, and violet ketone being preferred, and anthraquinone and violet ketone being more preferred.

[0120] The infrared-transmitting colorant preferably has a nickel content of 0.8% by mass or less. By setting it to 0.8% by mass or less, environmental adaptability is improved. Furthermore, there is a tendency for improved laser marking properties.

[0121] Examples of commercially available products include colorants manufactured by ORIENT CHEMICAL INDUSTRIES CO.,LTD. such as e-BINDLTW-8731H, e-BIND LTW-8701H, and e-BIND LTW-8904; colorants manufactured by Ayon Chemical Co., Ltd. such as PlastYellow 8000, Plast Red M 8315, Plast Red 8370, and Oil Green 5602; colorants manufactured by LANXES such as Macrolex Yellow 3G, Macrolex Red EG, and Macrolex Green 5B; and colorants manufactured by Kiwa Chemical Industry Co., Ltd. such as KP Plast HK, KP Plast Red HG, KP Plast Red H2G, KP Plast Blue R, KP Plast Blue GR, and KP Plast Green G.

[0122] Alternatively, the colorants described in Japanese Patent No. 4157300 and Japanese Patent No. 4040460 may be used, and these contents are incorporated into this specification.

[0123] In this embodiment, the content of the infrared-transmitting colorant (preferably an infrared-transmitting dye) in the resin composition is 0.01 parts by weight or more, preferably 0.03 parts by weight or more, more preferably 0.05 parts by weight or more, further preferably 0.1 parts by weight or more, and even more preferably 0.2 parts by weight or more, relative to 100 parts by weight of the thermoplastic polyester resin. By setting this to the aforementioned lower limit value or above, the molded article is colored, and the designability is improved. Furthermore, the aforementioned upper limit value is 5 parts by weight or less, preferably 3 parts by weight or less, more preferably 2 parts by weight or less, further preferably 1 part by weight or less, and even more preferably 0.8 parts by weight or less. By setting this to the aforementioned upper limit value or below, the exudation of the infrared-transmitting colorant can be effectively suppressed.

[0124] The resin composition of this embodiment may contain only one type or two or more infrared-transmitting colorants. When two or more types are contained, the total amount is preferably within the range described above.

[0125] Furthermore, the resin composition of this embodiment is generally substantially free of light-absorbing pigments (e.g., carbon black). "Substantially free" means that, in the case where the light-transmitting resin composition contains a light-absorbing colorant, the amount is below the level that does not impede the light transmission of the light-transmitting resin composition for laser welding. For example, it is less than 0.001 parts by weight relative to 100 parts by weight of thermoplastic resin.

[0126] <Reactive Compounds>

[0127] The resin composition of this embodiment may further contain reactive compounds (preferably epoxy compounds) or may not contain reactive compounds (preferably epoxy compounds). By containing reactive compounds, there is a tendency for increased weld strength.

[0128] The reactive compound is preferably a compound that reacts chemically with the carboxyl or hydroxyl groups present at the ends of the polybutylene terephthalate resin, thereby producing a crosslinking reaction and chain elongation. Preferably, the reactive compound comprises one or more compounds selected from the group consisting of epoxy compounds, carbodiimide compounds, compounds having an oxazoline group (ring), compounds having an oxazine group (ring), compounds having a carboxyl group, and compounds having an amide group; more preferably, it comprises at least one compound selected from epoxy compounds and carbodiimide compounds; and even more preferably, it comprises an epoxy compound. In particular, in the resin composition of this embodiment, 90% by mass or more, more preferably 95% by mass or more, and especially preferably 99% by mass or more of the reactive compound is an epoxy compound.

[0129] There are no particular limitations on the epoxy compound as long as it has one or more epoxy groups in one molecule; well-known epoxy compounds can be widely used. By including epoxy compounds, there is a tendency to extend the range of laser irradiation conditions.

[0130] Examples of first embodiments of epoxy compounds include non-elastic compounds such as glycidyl compounds, epoxy compounds having aromatic rings, and alicyclic epoxy compounds, preferably including at least epoxy compounds having aromatic rings.

[0131] Specific examples of the first embodiment of the epoxy compound include bisphenol A type epoxy compounds (containing bisphenol A diglycidyl ether), bisphenol F type epoxy compounds (containing bisphenol F diglycidyl ether), biphenyl type epoxy compounds (containing bis(glycidyloxy)biphenyl), resorcinol type epoxy compounds (containing resorcinol diglycidyl ether), phenolic varnish type epoxy compounds, glycidyl benzoate, diglycidyl terephthalate, diglycidyl phthalate and other epoxy compounds having aromatic rings, methyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, etc. Oil ethers, decyl glycidyl ethers, stearyl glycidyl ethers, phenyl glycidyl ethers, butyl phenyl glycidyl ethers, allyl glycidyl ethers, neopentyl glycol diglycidyl ethers, ethylene glycol diglycidyl ethers, glycerol diglycidyl ethers, propylene glycol diglycidyl ethers, etc. (II) glycidyl ethers, glycidyl sorbate, diglycidyl adipic acid, epoxidized linseed oil, epoxidized soybean oil, etc., alkanes (e.g., saturated fatty acid systems) or alkenes (e.g., unsaturated fatty acid systems), (II) glycidyl esters, vinyl cyclohexene dioxide, dicyclopentadiene oxide, etc., alicyclic epoxides.

[0132] Among them, bisphenol A type epoxy compounds, phenolic varnish type epoxy compounds, bisphenol F type epoxy compounds, biphenyl type epoxy compounds, etc. are preferred, and o-cresol / phenolic varnish type epoxy resins (o-cresol / formaldehyde condensate polyglycidyl ether compounds) are even more preferred.

[0133] Commercially available products include "Joncryl ADR4368C" (trade name: BASF Corporation), Epikote 1003 (trade name: Mitsubishi Chemical Corporation), and Nippon Steel & Sumitomo Chemical Co., Ltd. (trade name: YDCN704).

[0134] The mass-average molecular weight of the epoxy compound in the first embodiment is preferably 15,000 or less, more preferably 10,000 or less. There is no particular limitation on the lower limit, but the mass-average molecular weight is preferably 100 or more, more preferably 500 or more. By setting it within this range, the effects of this embodiment tend to be more effectively achieved.

[0135] The epoxy equivalent of the epoxy compound in the first embodiment is preferably 100 g / eq or more, or 100 g / mol or more, more preferably 150 g / eq or more, or 150 g / mol or more. Furthermore, the epoxy equivalent of the epoxy compound is preferably 1500 g / eq or less, or 1500 g / mol or less, more preferably 900 g / eq or less, or even more preferably 800 g / eq or less, or 800 g / mol or less.

[0136] By setting the epoxy equivalent to or above the aforementioned lower limit, there is a tendency for the weld strength and hydrolysis resistance of the welded body to become higher. By setting it to or below the aforementioned upper limit, there is a tendency for the resin composition to have higher flowability and become easier to mold.

[0137] A second embodiment of the epoxy compound contains an elastomer comprising epoxy groups. By containing an elastomer comprising epoxy groups, it is possible to obtain molded articles with higher impact resistance.

[0138] A first embodiment of an epoxy-containing elastomer is a copolymer obtained by copolymerizing an α-olefin, a glycidyl ester of an α,β-unsaturated acid, and an unsaturated monomer that can copolymerize with them as needed. Preferably, 60% by mass or more of the α-olefin and the glycidyl ester of the α,β-unsaturated acid are used in all copolymer components.

[0139] Examples of α-olefins include ethylene, propylene, butene-1, and pentene-1. Two or more of these can be used. Examples of glycidyl esters of α,β-unsaturated acids include glycidyl acrylate, glycidyl methacrylate, glycidyl ethyl acrylate, and glycidyl itaconic acid. Two or more of these can be used. Examples of vinyl monomers that can copolymerize with the above components include vinyl ethers, vinyl acetate, vinyl propionate, methyl, ethyl, propyl, butyl, and other vinyl esters, acrylic and methacrylate esters, acrylonitrile, and styrene. Two or more of these can be used.

[0140] Preferred examples of epoxy-containing elastomers in the first embodiment include ethylene / glycidyl methacrylate copolymers, ethylene / glycidyl methacrylate / vinyl acetate copolymers, ethylene / glycidyl methacrylate / alkyl acrylate copolymers, and ethylene / alkyl acrylate / vinyl acetate copolymers. From the viewpoint of excellent toughness and further improved resistance to damp heat and impact of molded articles, ethylene / glycidyl methacrylate / alkyl acrylate (preferably butyl acrylate) copolymers are particularly preferred. Specific examples of epoxy-containing elastomers in the first embodiment are available under trade names such as "LOTADER" (registered trademark) AX8900 and AX8700 manufactured by Arkema.

[0141] A second embodiment of the epoxy-containing elastomer is a core-shell elastomer. By using a core-shell elastomer, the molecular particle size is small, thus it is easily dispersed in polybutylene terephthalate resins, and there is a tendency for improved weld strength through the reaction of reactive groups. An example of a core-shell elastomer is one formed by grafting monomer components onto a copolymer of the core polymer.

[0142] The core is preferably a rubber-based polymer, such as acrylonitrile / acrylic rubber-based polymer / styrene graft copolymer (ASA resin), methyl methacrylate / acrylic rubber-based polymer / styrene graft copolymer (MSA resin), methyl methacrylate / acrylonitrile / acrylic rubber-based polymer / styrene graft copolymer (MASA resin), rubber-based polymers containing polyorganosiloxanes, etc., with rubber-based polymers containing polyorganosiloxanes being more preferred.

[0143] The glass transition temperature of rubber polymers containing polyorganosiloxanes is typically below 0°C, preferably below -20°C, and more preferably below -30°C. Specific examples of rubber components are not particularly limited to rubbers containing polyorganosiloxanes; examples include polyorganosiloxane rubbers and (IPN type) composite rubbers of polyorganosiloxane rubbers and polyalkyl acrylate rubbers.

[0144] Specific examples of monomeric components capable of graft copolymerization with the nucleus include aromatic vinyl compounds, cyanide vinyl compounds, (meth)acrylate compounds, (meth)acrylate compounds, glycidyl (meth)acrylate and other epoxy-containing (meth)acrylate compounds, maleimide compounds such as maleimide, N-methylmaleimide, N-phenylmaleimide, etc.; α,β-unsaturated carboxylic acid compounds such as maleic acid, phthalic acid, itaconic acid, etc., and their anhydrides (such as maleic anhydride, etc.).

[0145] Specific examples of rubber polymers, aromatic vinyl compounds, cyanide vinyl compounds, and (meth)acrylate compounds can be found in paragraphs 0042 to 0046 of Japanese Patent Application Publication No. 2019-059813, and these contents are incorporated herein by reference.

[0146] The epoxy-containing elastomer of the second embodiment is preferably a compound obtained by grafting an epoxy-containing (meth)acrylate compound onto a rubbery polymer containing a polyorganosiloxane (preferably a composite rubber of polyorganosiloxane rubber and polyalkyl acrylate rubber).

[0147] Specific examples of epoxy-containing elastomers in the second embodiment include, for example, "Metablen (registered trademark, hereinafter the same) S-2002" manufactured by Mitsubishi Rayon Co., Ltd.

[0148] Furthermore, the epoxy compounds that can be used in this embodiment can be referred to in paragraphs 0060 to 0067 of Japanese Patent Application Publication No. 2019-019305, the contents of which are incorporated into this specification.

[0149] When the resin composition of this embodiment contains a reactive compound (preferably an epoxy compound), its content relative to 100 parts by weight of the thermoplastic polyester resin is preferably 0.2 parts by weight or more, more preferably 0.3 parts by weight or more, even more preferably 0.4 parts by weight or more, further preferably 0.5 parts by weight or more, and even more preferably 0.8 parts by weight or more. By setting it to the aforementioned lower limit or above, there is a tendency for increased weld strength. Furthermore, the upper limit of the aforementioned reactive compound content relative to 100 parts by weight of the thermoplastic polyester resin is preferably 18 parts by weight or less, more preferably 15 parts by weight or less, and even more preferably 10 parts by weight or less. By setting it to the aforementioned upper limit or below, there is a tendency for increased fluidity and improved moldability.

[0150] The resin composition of this embodiment may contain only one type or two or more reactive compounds. When two or more types are contained, the total amount is preferably within the range described above.

[0151] <Inorganic fillers>

[0152] The resin composition of this embodiment preferably further comprises an inorganic filler. By including an inorganic filler, especially a fibrous inorganic filler, preferably glass fiber, there is a tendency to improve mechanical strength, increase heat resistance, and further improve the durability of laser-welded products.

[0153] The inorganic filler used in the resin composition of this embodiment can improve the mechanical properties of the resin composition obtained by compounding it with the resin. Commonly used inorganic fillers for plastics can be used. Fibrous inorganic fillers such as glass fiber, carbon fiber, basalt fiber, wollastonite, and potassium titanate fiber are preferred. In addition, granular or amorphous fillers such as calcium carbonate, titanium dioxide, feldspar minerals, clay, organic clay, and glass beads can also be used; plate-shaped fillers such as talc; and flake-shaped inorganic fillers such as glass flakes, mica, and graphite. Among these, fibrous fillers are preferred from the perspective of mechanical strength, rigidity, and heat resistance, and glass fiber is particularly preferred. As for glass fiber, both round and irregular cross-sectional shapes can be used.

[0154] Inorganic fillers are more preferably those that have undergone surface treatment using coupling agents or other surface treatment agents. Glass fibers coated with surface treatment agents exhibit excellent durability, resistance to damp heat, resistance to hydrolysis, and resistance to heat shock, and are therefore preferred.

[0155] As a surface treatment agent, any conventionally known agent can be used. Specifically, silane coupling agents such as aminosilane-based, epoxysilane-based, allylsilane-based, and vinylsilane-based agents are preferred. Among these, aminosilane-based surface treatment agents are preferred, and γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-(2-aminoethyl)aminopropyltrimethoxysilane are preferred examples.

[0156] In addition, other surface treatment agents include epoxy resin-based surface treatment agents such as phenolic varnish type and bisphenol A type epoxy resin-based surface treatment agents, and treatment using phenolic varnish type epoxy resin-based surface treatment agents is particularly preferred.

[0157] Silane-based surface treatment agents and epoxy resin-based surface treatment agents can be used individually or in combination, and preferably in combination. In this embodiment, glass fiber refers to fibrous glass material; more specifically, it is preferably a chopped shape obtained by bundling 1000 to 10000 glass fibers and cutting them to a specified length.

[0158] In this embodiment, the number-average fiber length of the glass fiber is preferably 0.5–10 mm, more preferably 1–5 mm. By using glass fibers with this number-average fiber length, the mechanical strength can be further improved. The number-average fiber length is determined as follows: for an image obtained from observation under an optical microscope, glass fibers of the object whose fiber length is to be measured are randomly selected, their long side is measured, and the number-average fiber length is calculated from the measured value. The observation magnification is set to 20x, and the number of measurements is set to 1000 or more. This is approximately equivalent to the cutting length.

[0159] Furthermore, the cross-section of the glass fiber can be any shape, such as circular, elliptical, oblong, rectangular, or a rectangle with two short sides plus a semicircle, or an eyebrow shape, but circular is preferred. Here, "circular" refers not only to a circle in a geometric sense, but also to anything commonly referred to as circular in the technical field of this embodiment.

[0160] The lower limit of the number-average fiber diameter of glass fibers is preferably 4.0 μm or more, more preferably 4.5 μm or more, and even more preferably 5.0 μm or more. The upper limit of the number-average fiber diameter of glass fibers is preferably 15.0 μm or less, more preferably 14.0 μm or less. By using glass fibers with a number-average fiber diameter within this range, it is possible to obtain molded articles with superior mechanical strength. It should be noted that the number-average fiber diameter of glass fibers is determined as follows: for images obtained from observation by an electron microscope, glass fibers of the object whose fiber diameter is to be measured are randomly selected, and the fiber diameter is measured at a position close to the center, and the measured value is calculated. The observation magnification is set to 1000x and the number of measurements is set to 1000 or more. The number-average fiber diameter of glass fibers with cross-sections other than circular is denoted as the number-average fiber diameter when converted to the area of ​​a circle with the same area as the cross-section.

[0161] The glass fibers used are obtained by melt spinning commonly supplied glass such as E-glass (Electrical glass), C-glass (Chemical glass), A-glass (Alkali glass), S-glass (High strength glass), D-glass, R-glass, and alkali-resistant glass. However, any glass that can be formed into glass fibers can be used, and there is no particular limitation. In this embodiment, E-glass is preferably included.

[0162] In this embodiment, the glass fiber is preferably surface-treated with a surface treatment agent such as γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-aminopropyltriethoxysilane, etc. The amount of surface treatment agent adhering is preferably 0.01 to 1% by mass of the glass fiber. Further, if necessary, a mixture of a resin with film-forming ability, such as a fatty acid amide compound, lubricant like silicone oil, antistatic agent like quaternary ammonium salt, epoxy resin, or polyurethane resin, or a mixture of a resin with film-forming ability and a heat stabilizer or flame retardant, may also be used.

[0163] Fiberglass is available as a commercially available product. Examples of commercially available products include those manufactured by Nippon Electric Glass Co., Ltd., such as T-286H, T-756H, T-127, and T-289H; those manufactured by Owens Corning Co., Ltd., such as DEFT2A; those manufactured by PPG Co., Ltd., such as HP3540; and those manufactured by Nittobo Co., Ltd., such as CSG3PA820.

[0164] In this embodiment, the content of the inorganic filler (preferably glass fiber) in the resin composition is preferably 10 parts by weight or more, more preferably 15 parts by weight or more, further preferably 20 parts by weight or more, even more preferably 25 parts by weight or more, and even more preferably 30 parts by weight or more, relative to 100 parts by weight of the thermoplastic resin component (the total of thermoplastic polyester resin, polycarbonate resin, butadiene-containing polystyrene, etc.). By setting the content at or above the aforementioned lower limit, the base material strength of the laser-welded product tends to increase, and the heat resistance of the laser-welded product tends to increase. Furthermore, the upper limit of the aforementioned inorganic filler content is preferably 70 parts by weight or less, more preferably 60 parts by weight or less, and even more preferably 50 parts by weight or less, relative to 100 parts by weight of the thermoplastic resin. By setting the content at or below the aforementioned upper limit, the weld strength at the interface tends to increase.

[0165] Furthermore, the content of the inorganic filler (preferably glass fiber) in the resin composition of this embodiment is preferably 20% by mass or more, more preferably 25% by mass or more, of the resin composition. Additionally, the content of the aforementioned inorganic filler (preferably glass fiber) is preferably 40% by mass or less, more preferably 38% by mass or less.

[0166] The resin composition of this embodiment may contain only one type or two or more inorganic fillers (preferably glass fiber). When two or more types are contained, the total amount is preferably within the range described above.

[0167] <Stabilizer>

[0168] The resin composition of this embodiment preferably contains a stabilizer, and phosphorus-based stabilizers and phenolic stabilizers are preferred as stabilizers.

[0169] As a phosphorus-based stabilizer, any known stabilizer can be used. Specific examples include oxyacids of phosphorus such as phosphoric acid, phosphonic acid, phosphorous acid, hypophosphite, and polyphosphoric acid; acidic metal pyrophosphates such as sodium pyrophosphate, potassium pyrophosphate, and calcium pyrophosphate; phosphates of Group 1 or Group 2 metals such as potassium phosphate, sodium phosphate, cesium phosphate, and zinc phosphate; organophosphate compounds, organophosphite compounds, and organophosphonates, etc., but organophosphite compounds are particularly preferred.

[0170] Examples of phenolic stabilizers include hindered phenolic antioxidants.

[0171] For details, please refer to paragraphs 0105 to 0111 of International Publication No. 2020 / 013127, the contents of which are incorporated into this specification.

[0172] The content of the stabilizer relative to 100 parts by weight of the thermoplastic polyester resin is typically 0.001 parts by weight or more, preferably 0.01 parts by weight or more, and typically 2.0 parts by weight or less, preferably 1.0 parts by weight or less. By setting the stabilizer content to the lower limit of the aforementioned range or above, the effect of the stabilizer can be obtained more effectively. Furthermore, by setting the stabilizer content to the upper limit of the aforementioned range or below, the effect is not maximized, which is economical.

[0173] The resin composition of this embodiment may contain only one type of stabilizer or two or more types. When two or more types are contained, the total amount is preferably within the range described above.

[0174] <Other Ingredients>

[0175] The resin composition of this embodiment may contain other components besides those described above, as long as they do not significantly impair the desired physical properties. Examples of other components include various resin additives. It should be noted that one other component may be included, or two or more components may be included in any combination and ratio.

[0176] Specifically, examples include thermoplastic polyester resins, butadiene-containing polystyrene resins and other thermoplastic resins besides polycarbonate resins, flame retardants, mold release agents, ultraviolet absorbers, antistatic agents, antifogging agents, mold release agents, flow improvers, plasticizers, dispersants, antibacterial agents, etc. The resin composition of this embodiment preferably includes at least one of a stabilizer and a mold release agent.

[0177] In this embodiment, the total amount of thermoplastic polyester resin, butadiene-containing polystyrene, and polycarbonate resin preferably accounts for 90% or more by mass, more preferably 95% or more by mass, and more preferably 99% or more by mass of the thermoplastic resin component contained in this embodiment. The upper limit is 100% by mass.

[0178] In the resin composition of this embodiment, the content of pigments other than the infrared-transmitting colorant is preferably 1% by mass or less than the content of the aforementioned infrared-transmitting colorant. By setting it in this way, the effects of the present invention can be exerted more effectively.

[0179] Furthermore, in the resin composition of this embodiment, the content of aniline black is preferably 1% by mass or less than the content of the aforementioned infrared-transmitting colorant. By setting it in this way, the effects of the present invention can be exerted more effectively.

[0180] <Characteristics of the Resin Composition>

[0181] The resin composition of this embodiment is preferably capable of laser marking and exhibits excellent print clarity. For example, the resin composition is preferably capable of laser marking with a color hue that has a higher brightness than that of an infrared-transmitting colorant (black colorant and / or black colorant composition, preferably black dye and / or black dye composition). That is, in a black transmissive resin component, laser marking is preferably performed with a color brighter than black. More specifically, when the resin composition of this embodiment is molded to a thickness of 1.5 mm, the color difference ΔE (absolute value) between the hue of the laser-marked portion and the hue of the non-laser-marked portion when laser marking is performed on a portion is preferably 7.0 or more, more preferably 10.0 or more, and even more preferably 11.0 or more. The aforementioned upper limit of the color difference ΔE is not particularly limited; for example, 25.0 or less is practical.

[0182] Furthermore, in this embodiment, the color difference ΔE between the laser marking portion in the transmissive resin component and the absorbing resin component based on the SCE method is preferably large. Specifically, the color difference ΔE between the laser marking portion in the 1.5 mm thick transmissive resin component formed by the resin composition of this embodiment and the 1.5 mm thick absorbing resin component formed by the light-absorbing resin composition comprising a thermoplastic resin and a light-absorbing pigment is preferably 8.0 or more, more preferably 10.0 or more. As an upper limit, there is no particular limitation, and even 30.0 or less, and further 25.0 or less, is sufficient to meet the required performance.

[0183] The resin composition of this embodiment preferably exhibits excellent laser transmittance. Specifically, when the aforementioned resin composition is molded into a 1.5 mm thick test piece, the transmittance at a wavelength of 1064 nm is preferably 12% or more, more preferably 20% or more, further preferably 25% or more, and even more preferably 35% or more. By setting this to the aforementioned lower limit value or above, there is a tendency for further improvement in laser weldability. In addition, the resin composition of this embodiment contains an infrared-transmitting colorant, therefore, the transmittance has a substantial upper limit value, which is, for example, 90% or less, and can be 80% or less. The test piece here refers to the non-laser-marked portion.

[0184] The resin composition of this embodiment preferably exhibits excellent tensile strength retention after 100 hours of high temperature and high humidity treatment (PCT (121°C × 2 atm × 100% RH)). Specifically, for the resin composition of this embodiment, the tensile strength retention rate after 100 hours of PCT treatment, measured according to ISO 527-1 and 527-2, is preferably 35% or more, more preferably 40% or more, and even more preferably 50% or more. There is no particular limitation on the upper limit; for example, 95% or less is practical.

[0185] The details of the hue, color difference, light transmittance, and tensile strength retention rate after high temperature and high humidity treatment based on the SCE method were measured according to the description of the embodiments described later.

[0186] Furthermore, as a resin composition in this embodiment, an example is a resin composition comprising a thermoplastic polyester resin and an infrared-transmitting colorant, wherein when molded into a 1.5 mm thick test piece, the transmittance at a wavelength of 1064 nm is 12% or more, and when molded into a 1.5 mm thick piece, the color difference ΔE between the hue of the laser-marked portion and the hue of the non-laser-marked portion, based on the SCE method, is 7.0 or more. Such a composition can be adjusted, for example, by blending polystyrene containing butadiene rubber and examining its type.

[0187] <Method for manufacturing resin composition>

[0188] The resin composition of this embodiment can be manufactured according to conventional methods for preparing resin compositions. Typically, the components and various additives to be added as desired are thoroughly mixed together, and then melt-blended in a single-screw or twin-screw extruder. Alternatively, the resin composition of this embodiment can also be prepared by not pre-mixing the components, or by pre-mixing only a portion of them, and then feeding them to the extruder using a feeder for melt blending. Alternatively, a portion of the components, such as colorants, can be melt-blended with a thermoplastic resin to prepare a masterbatch, and then the remaining components are blended therein for melt blending.

[0189] It should be noted that when using inorganic fillers, it is preferable to supply them from a side feeder in the middle of the extruder barrel.

[0190] The heating temperature during melt mixing can typically be appropriately selected within the range of 220–300°C. If the temperature is too high, decomposition gases are easily generated, sometimes causing opacity. Therefore, it is desirable to select a screw configuration that takes into account shear heat release, etc. To suppress decomposition during mixing and subsequent molding strokes, it is desirable to use oxidizing agents and heat stabilizers.

[0191] <Molded articles and methods for manufacturing molded articles>

[0192] The resin composition of this method can be molded according to known methods.

[0193] There are no particular limitations on the manufacturing method of the molded article; any molding method commonly used for polyester resin compositions can be employed. Examples include injection molding, high-speed injection molding, injection compression molding, two-color molding, gas-assisted hollow molding, molding using insulated molds, molding using rapidly heated molds, foam molding (including supercritical fluids), insert molding, IMC (in-mold coating) molding, extrusion molding, sheet molding, thermoforming, rotational molding, lamination molding, pressure molding, and blow molding, among which injection molding is preferred.

[0194] For details regarding injection molding, please refer to paragraphs 0113 to 0116 of Japanese Patent No. 6183822, which are incorporated herein by reference.

[0195] The molded article of this embodiment is formed from the resin composition of this embodiment and is used as a laser-transmitting resin component during laser welding. Furthermore, the laser-transmitting resin component formed from the resin composition of this embodiment can be used for laser marking.

[0196] An example of a molded article according to this embodiment is a molded article formed by molding a composition comprising a thermoplastic polyester resin and an infrared-transmitting colorant, wherein the light transmittance at a wavelength of 1064 nm is 12% or more, and the color difference ΔE between the hue of the laser-marked portion and the hue of the non-laser-marked portion is 7.0 or more when laser marking is performed based on the SCE method.

[0197] <Reagent kit and laser-marked laser-welded products>

[0198] The kit of this embodiment comprises: the resin composition of this embodiment and a light-absorbing resin composition. The resin composition of this embodiment functions as a light-transmitting resin composition. This kit exhibits excellent laser weldability and is preferably used as a kit for manufacturing laser-welded molded articles (laser-welded articles). Furthermore, laser marking can also be performed. One example of the laser-welded article of this embodiment is a laser-welded article capable of laser marking, and another example is a laser-welded article with laser marking.

[0199] That is, the resin composition of this embodiment contained in the kit functions as a light-transmitting resin composition, and the molded article formed from the above-mentioned light-transmitting resin composition becomes a light-transmitting resin component for laser welding. On the other hand, the molded article formed from the light-absorbing resin composition becomes a light-absorbing resin component for laser welding. Furthermore, the light-transmitting resin component also serves as a substrate for laser marking.

[0200] In addition, in this embodiment, the color difference ΔE between the non-laser-marked portion of the laser-transmitting resin component and the laser-absorbing resin component based on the SCE method is preferably small.

[0201] Specifically, in this embodiment, the reagent kit is preferably prepared such that the resin composition and the light-absorbing resin composition of this embodiment are each molded to a thickness of 1.5 mm, and the difference in hue L based on the SCE method, i.e., ΔE, is 6.0 or less. The molded sheet in this case refers to the state without laser marking. More preferably, ΔE is 4.0 or less, and more preferably 3.8 or less. While 0 is ideal as a lower limit, even 0.5 or more, and further 1.0 or more, sufficiently meets the required performance.

[0202] That is, the laser-welded article of this embodiment can be manufactured by a manufacturing method including the following steps: irradiating a laser with a laser to a laser-transmitting resin member formed of the resin composition of this embodiment to perform laser marking; and laser welding the laser-transmitting resin member to a laser-absorbing resin member formed of a light-absorbing resin composition comprising a thermoplastic resin and a light-absorbing pigment. In manufacturing the laser-welded article of this embodiment, laser welding and laser marking can be performed either first or simultaneously.

[0203] <<Light-absorbing resin composition>>

[0204] The light-absorbing resin composition used in this embodiment comprises a thermoplastic resin and a light-absorbing pigment. Furthermore, it may also include a reinforcing material.

[0205] Examples of thermoplastic resins include polyamide resins, olefin resins, vinyl resins, styrene resins, acrylic resins, polyphenylene ether resins, polyester resins, polycarbonate resins, and polyacetal resins. From the perspective of good compatibility with the light-transmitting resin composition (the resin composition of this embodiment), polyester resins and polycarbonate resins are particularly preferred, and polyester resins are even more preferred. Furthermore, one type of thermoplastic resin may be used, or two or more types may be used.

[0206] As a thermoplastic resin component used in the light-absorbing resin composition, it is preferable to cite a thermoplastic resin component that is the same as that contained in the resin composition (light-transmitting resin composition) of this embodiment.

[0207] The inorganic filler is preferably the same as the inorganic filler described in the resin composition (light-transmitting resin composition) of this embodiment, and the preferred ranges for the mixing amount are also the same.

[0208] As a light-absorbing pigment, it has a maximum absorption wavelength within the range of the wavelength of the irradiated laser beam, that is, in this embodiment, the wavelength range of 800 nm to 1100 nm. A light-absorbing pigment is, for example, a pigment that, when mixed with 30% by mass of a blended polybutylene terephthalate resin (e.g., Novaduran (registered trademark) 5008), glass fiber (e.g., manufactured by Nippon Electric Glass Co., Ltd., trade name: T-127), and 0.3 parts by mass of pigment (a pigment considered to be a light-absorbing pigment), has a transmittance of less than 15%, and further less than 10%, when measured by the measurement method described in the examples below.

[0209] Specific examples of light-absorbing pigments include inorganic pigments (black pigments such as carbon black (e.g., acetylene black, lampblack, thermal cracking carbon black, furnace black, channel black, Ketjen black, etc.), red pigments such as iron oxide red, orange pigments such as molybdenum chrome red, and white pigments such as titanium dioxide), and organic pigments (yellow pigments, orange pigments, red pigments, blue pigments, green pigments, etc.). Among these, inorganic pigments are generally preferred due to their strong hiding power, and black pigments are even more preferred. These light-absorbing pigments can be used in combination of two or more. The content of the light-absorbing pigment relative to 100 parts by weight of the resin component is preferably 0.01 to 30 parts by weight.

[0210] The above-mentioned kit preferably contains at least 80% by mass of the components in the resin composition of this embodiment, excluding the colorant and the reinforcing material, and at least 90% by mass of the components in the light-absorbing resin composition, excluding the light-absorbing pigment and the reinforcing material, and even more preferably at least 95% by mass.

[0211] <<Laser Welding Methods>>

[0212] Next, the laser welding method will be described. In this embodiment, a molded article (a resin-transmitting component) formed from the resin composition of this embodiment and a molded article (an absorbent resin component) formed from the aforementioned light-absorbing resin composition can be laser-welded to manufacture a molded article. That is, as a manufacturing method of this embodiment, a method for manufacturing a molded article is disclosed, which includes the step of laser welding a resin-transmitting component and an absorbent resin component, wherein the resin-transmitting component is formed from the resin composition of this embodiment. By performing laser welding, the resin-transmitting component and the absorbent resin component can be firmly welded without the use of adhesives.

[0213] The resin composition of this embodiment can be laser welded using any known laser welding method, and is suitable for current-scanning laser welding. Current-scanning laser welding, also known as quasi-simultaneous welding, uses a built-in current mirror to scan the laser beam. By using current-scanning laser welding, the entire weld area is heated substantially simultaneously, thus tending to result in less residual stress in the laser-welded product.

[0214] The shapes of the resin-transmitting component and the resin-absorbing component are not particularly limited. The components are joined together by laser welding, and therefore, they typically have at least a surface contact area (planar or curved). During laser welding, the laser beam passing through the resin-transmitting component is absorbed and melted by the resin-absorbing component, and the two components are welded together. The molded article formed from the resin composition of this embodiment can improve the transmittance to the laser beam; therefore, it is preferably used as a resin-transmitting component. Here, the thickness of the component through which the laser beam passes (the thickness in the laser transmission direction of the portion through which the laser beam passes) can be suitably determined considering the application, the composition of the resin composition, and other factors, for example, it is 5 mm or less, preferably 4 mm or less.

[0215] The laser beam source used in laser welding can be determined based on the absorption wavelength of the light from the photoabsorbent pigment, with a wavelength range of 800–1100 nm being preferred. Examples of laser beam types include solid-state lasers, fiber lasers, semiconductor lasers, gas lasers, and liquid lasers. For example, YAG (yttrium / aluminum / garnet crystal) lasers (wavelengths 1064 nm and 1070 nm) and LD (laser diode) lasers (wavelengths 808 nm, 840 nm, 940 nm, and 980 nm) are preferred. Among these, laser beams with wavelengths of 940 nm, 980 nm, and 1070 nm are particularly preferred.

[0216] The laser focal diameter is preferably Φ0.1mm or more, more preferably 0.2mm or more, and even more preferably 0.5mm or more. By setting it to the aforementioned lower limit or above, the welding strength of the laser-welded part can be further improved. Furthermore, the laser irradiation diameter is preferably... The weld width is preferably 10 mm or less, and even more preferably 3.0 mm or less. By setting it to the aforementioned upper limit value or less, the weld width can be controlled more effectively.

[0217] It should be noted that the focal diameter of the laser beam can be selected according to the width and height of the welding surface.

[0218] In addition, the laser beam can be focused or defocused at the joint surface, preferably depending on the desired weld.

[0219] The laser power is preferably 1W or more, more preferably 10W or more, further preferably 30W or more, and even more preferably 100W or more. By setting it to the aforementioned lower limit or above, sufficient weld strength can be obtained even with a short welding time. Furthermore, the laser power is preferably 1000W or less, more preferably 500W or less, further preferably 400W or less, and even more preferably 300W or less. By setting it to the aforementioned upper limit or below, the cost of laser welding equipment can be effectively suppressed.

[0220] The laser irradiation speed (scanning speed) is preferably 10 mm / s or more, more preferably 30 mm / s or more, further preferably 50 mm / s or more, and even more preferably 500 mm / s or more. By setting it to the aforementioned lower limit or above, residual stress in the laser-welded workpiece can be reduced more effectively. Furthermore, the laser irradiation speed is preferably 20,000 mm / s or less, more preferably 10,000 mm / s or less, further preferably 5,000 mm / s or less, and even more preferably 3,000 mm / s or less. By setting it to the aforementioned upper limit or below, more sufficient weld strength can be obtained for the welded body. In addition, regarding the laser scanning method, from the viewpoints of welding efficiency, weld strength, weld appearance, and device load, it is preferable to adjust the laser power, the predetermined welding path, the scanning speed, and / or the scanning method according to the shape of the joint surface.

[0221] More specifically, in the case of welding a transparent resin component and an absorbent resin component, the welding points are first brought into contact with each other. Ideally, the welding points should be surface-to-surface contact, but they can also be planar, curved, or a combination of planar and curved surfaces. While maintaining this overlap, a transparent sheet such as a glass plate, quartz plate, or acrylic plate can be placed on the transparent resin component, i.e., the laser irradiation side, and pressure can be applied. In particular, using a glass plate or quartz plate is suitable for promoting the release of heat generated during laser welding and obtaining a good appearance. Alternatively, pressure can be applied using a metal plate surrounding the predetermined welding area of ​​the transparent resin component.

[0222] Then, a laser beam is irradiated from the side of the resin-permeable component. At this point, a lens can be used to focus the laser beam at the interface between the two components, if necessary. The focused beam passes through the resin-permeable component, is absorbed near the surface of the absorbing resin component, and is heated and melted. This heat is then transferred to the resin-permeable component via thermal conduction, melting it and forming a molten groove at the interface. After cooling, the two components bond together.

[0223] Laser-welded articles formed by resin components and absorbing resin components exhibit high weld strength. It should be noted that the essence of the molded article in this embodiment is that, in addition to finished products and parts, it also includes components that form part of these.

[0224] For laser-welded articles consisting of a laser-transmitting resin component formed from the above-described resin composition and a laser-absorbing resin component formed from a light-absorbing resin composition comprising a thermoplastic resin and a light-absorbing pigment, the laser welding intensity can be set to 800 N or more, 1000 N or more, 1100 N or more, or 1200 N or more. There is no particular upper limit to the laser welding intensity; 4000 N or less is practical. The laser welding intensity is measured according to the embodiments described later.

[0225] <<Laser Marking Method>>

[0226] Molded articles formed from the resin composition of this embodiment can be laser-marked. That is, laser-welded articles formed from the resin-transmitting component and the resin-absorbing component of this embodiment can be laser-marked on the resin-transmitting component side.

[0227] Laser marking allows for the application of text, markings, barcodes, QR codes (registered trademarks), images, and patterns onto resin components. Widely known methods can be used for laser marking.

[0228] The wavelength of the laser beam used in the laser marking method is preferably 500 nm or more. Furthermore, the upper limit of the aforementioned laser oscillation wavelength is preferably 1200 nm or less.

[0229] Specifically, in resin-based color printing applications, laser marking with wavelengths such as 1064nm, 1090nm, and 1060nm is used. Alternatively, laser marking can be achieved by applying high-power light to crystals such as neodymium-modified yttrium-aluminum-garnet (YAG) or neodymium-modified yttrium-vanadium tetroxide (Nd:YVO4) to generate laser light, which is then amplified by reciprocating reflection through mirrors and pulsed using a Q-switching device. Additionally, fiber-based laser marking (using multiple low-power laser diodes (LDs) embedded in ytterbium fibers to generate / amplify the laser beam) can be used, which has become increasingly mainstream in recent years. Furthermore, green laser marking with a wavelength of 532nm can also be employed.

[0230] It should be noted that the laser beam used for laser marking can be in signal mode or multiple modes. In addition to a contracted beam with a beam diameter of 20 to 40 μm, a wide beam with a beam diameter of 80 to 100 μm can also be used. However, in signal mode, a beam with a beam diameter of 20 to 40 μm can mark with good contrast, so it is preferred.

[0231] <Uses>

[0232] The resin composition of this embodiment can be widely used in resin compositions containing polyester resin and colorant. Specifically, it can be used in various storage containers, electrical / electronic equipment components, office automation (OA) equipment components, home appliance components, mechanical mechanism components, vehicle mechanism components, etc. It is particularly suitable for food containers, pharmaceutical containers, oil and fat product containers, hollow vehicle components (various cans, intake manifold components, camera housings), vehicle electrical components (various control units, ignition coil components, etc.), motor components, various sensor components, connector components, switch components, circuit breaker components, relay components, coil components, transformer components, lamp components, etc.

[0233] The laser-welded products of this embodiment are particularly preferred for use in vehicle camera components, sensor housing components, motor components, and electronic control components. More specifically, they are suitable for vehicle camera components and vehicle camera assemblies containing vehicle camera components, housings of millimeter-wave radar, housings of ECU housings, housings of sensor housings such as acoustic sensors, and housings of motor components such as electric parking brakes.

[0234] Example

[0235] The present invention will be further described in detail below with examples. The materials, amounts, ratios, processing contents, and processing steps shown in the following examples can be appropriately modified without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0236] If the measuring equipment used in the embodiments is difficult to obtain due to issues such as serial numbers, other equipment with equivalent performance may also be used for measurement.

[0237] 1. Raw materials

[0238] Use the raw materials shown in Tables 1 and 2 below.

[0239] [Table 1]

[0240]

[0241] [Table 2]

[0242]

[0243] <Dye Adjustment>

[0244] The dyes used are made by weighing each dye and stirring for 5 hours.

[0245] It should be noted that all dyes listed in Table 2 above have a nickel content of less than 0.8% by mass.

[0246] 2. Examples 1-6, Comparative Examples 1-4

[0247] <Preparation of Light-Transmitting Resin Composition (Grit)>

[0248] As shown in Tables 3 and 4, the components other than glass fiber were placed in a stainless steel drum and mixed for 1 hour. The components in Tables 3 and 4 are marked as parts by mass. The resulting mixture was fed into the main hopper of a 30mm vented twin-screw extruder (manufactured by Nippon Steel Works Co., Ltd., "TEX30α"). Glass fiber (GF) was fed from the 7th side feeder from the hopper. The extruder was mixed under the following conditions: barrel temperature C1 to C15 set to 260°C, die temperature set to 250°C, screw speed set to 200 rpm, and discharge rate set to 40 kg / hour. The mixture was then extruded in filaments to obtain granules of the resin composition.

[0249] <Preparation of light-absorbing resin composition (granules)>

[0250] As shown in Table 5, the components other than glass fiber were placed in a stainless steel drum and mixed for 1 hour. The components in Table 5 are marked as parts by weight. The resulting mixture was fed into the main hopper of a 30mm vented twin-screw extruder (manufactured by Nippon Steel Works Co., Ltd., "TEX30α"). Glass fiber (GF) was fed from the 7th side feeder from the hopper. The extruder was mixed under the following conditions: barrel temperature C1 to C15 set to 260°C, die temperature set to 250°C, screw speed set to 200 rpm, and discharge rate set to 40 kg / hour. The mixture was then extruded in strands to obtain granules of the resin composition.

[0251] <Color tone measurement (SCE method), molding of plates for transmittance measurement (through resin components)>

[0252] After drying the resin composition granules obtained above at 120°C for 7 hours, an injection molding machine (NEX80-9E manufactured by Nissei Resin Kogyo Co., Ltd.) was used to injection mold 60mm×60mm×1.5mm thick plates for color measurement (SCE method) and for transmittance measurement (through resin component) under injection conditions of barrel temperature 260°C and mold temperature 60°C and below.

[0253] (Injection conditions)

[0254] Pressure holding time: 10 seconds

[0255] Cooldown: 10 seconds

[0256] Injection speed: 90 mm / s

[0257] Back pressure: 5MPa

[0258] Screw speed: 100 rpm

[0259] <Forming of a plate for color tone measurement (SCE method) (absorbent resin component)>

[0260] After drying the obtained granules at 120°C for 7 hours, an injection molding machine (NEX80-9E manufactured by Nissei Resin Kogyo Co., Ltd.) was used to injection mold a 60mm×60mm×1.5mm thickness color measurement plate (absorbent resin component) under injection conditions of barrel temperature 260°C and mold temperature 60°C or below.

[0261] (Injection conditions)

[0262] Pressure holding time: 10 seconds

[0263] Cooldown: 10 seconds

[0264] Injection speed: 90 mm / s

[0265] Back pressure: 5MPa

[0266] Screw speed: 100 rpm

[0267] <Laser Marking Characteristics>

[0268] The central part of the tone measurement plate (through the resin component) obtained above is laser-marked with a square size of 10mm × 10mm under the following conditions.

[0269] Laser marking device: Panasonic LP-Z310

[0270] Type of laser: Yb fiber laser (wavelength 1064nm)

[0271] Laser power: 80

[0272] Scanning speed: 200 mm / s

[0273] Printing pulse period: 50μs

[0274] A: Capable of performing excellent laser marking.

[0275] B: Other than A, laser marking is not possible, etc.

[0276] The hue L*a*b* (SCE) in the hue measurement plate (through the laser marking part (LM part) of the resin component and the hue measurement plate (through the non-laser marking part (non-LM part) of the resin component and the absorbing resin component) obtained above are measured as follows.

[0277] <<Color tone L*a*b*(SCE) (through resin components, non-laser marking area)>>

[0278] The hue L*a*b* (SCE) of the central portion of the hue measurement plate (through the resin component) obtained above was measured. The measurement was performed as follows: using a spectrophotometer according to ISO 7724 / 1, with D65 / 10 (reflected illumination, 10° direction light reception) and SCE (positive reflected light removal) colorimetric method, using a target mask SAV. The measurements were taken.

[0279] The spectrophotometer used is a Konica Minolta, Inc. CM-3600d.

[0280] <<Color tone L*a*b*(SCE) (through resin components, laser marking section)>>

[0281] The central portion of the hue measurement plate obtained above was laser-marked using the method described above, and the hue L*a*b* (SCE) (through the resin component) was measured. The measurement was as follows: using a spectrophotometer based on ISO 7724 / 1, with D65 / 10 (reflected illumination, 10° direction light reception) and SCE (positive reflected light removal) colorimetric method, and using a target mask SAV. The measurements were taken.

[0282] The spectrophotometer used is a Konica Minolta, Inc. CM-3600d.

[0283] <<Color tone L*a*b*(SCE)(Absorbent resin component)>>

[0284] The hue L*a*b* (SCE) of the central portion of the hue measurement plate (absorbing resin component) obtained above was measured. The measurement was performed using a spectrophotometer according to ISO 7724 / 1, employing the D65 / 10 (reflected illumination, 10° direction light reception) and SCE (positive reflected light removal) colorimetric method, using a target mask SAV. The measurements were taken.

[0285] The spectrophotometer used is a Konica Minolta, Inc. CM-3600d.

[0286] <<Tone Difference ΔE (SCE) (Transmission between the non-LM portion of the resin component and the absorbent resin component)>>

[0287] The hue difference ΔE is calculated based on the hue measurement results of the hue measurement plate (the non-laser marking part (non-LM part) of the resin component and the absorbing resin component) as measured above.

[0288] The results are shown in Tables 3 and 4 below.

[0289] <<Color difference ΔE (SCE) (through the LM section of the resin component and the absorbent resin component)>>

[0290] The difference ΔE of the hue difference is calculated based on the hue L*a*b* measurement results of the weather resistance test plate (the laser marking part (LM part) through the resin component and the absorbing resin component) as measured above.

[0291] The results are shown in Tables 3 and 4 below.

[0292] <1.5mm transmittance (backgate side)>

[0293] Using a UV-Vis-NIR spectrophotometer, the transmittance (%) at a wavelength of 1064 nm is determined from a point 45 mm from the gate side on the transmittance measurement plate (60 mm × 60 mm × 1.5 mm thickness) obtained above at the center of the width of the test plate.

[0294] The ultraviolet-visible-near-infrared spectrophotometer used is the "UV-3100PC" with integrating sphere manufactured by Shimadzu Corporation.

[0295] The results are shown in Tables 3 and 4 below.

[0296] <Tensile strength retention rate after PCT treatment>

[0297] After drying the granules of the light-transmitting resin composition obtained above at 120°C for 7 hours, they were injection molded into ISO multifunctional test pieces with a thickness of 4.0 mm using an injection molding machine (J-85AD-60H manufactured by Nippon Steel Corporation) in accordance with JIS7139 and JIS7152.

[0298] The initial tensile strength (MPa) of the ISO multifunctional test piece (4.0 mm thick) obtained above was determined according to JIS 7161. Additionally, for the ISO multifunctional test piece (4.0 mm thick), an autoclave testing machine (ESPEC EH8-221M) was used to treat it for 100 hours at 121°C, 100% relative humidity, and 2 atm pressure. After humidity adjustment at 23°C × 50%, the tensile strength (after 100 hours of treatment) was measured again (unit: MPa). The tensile strength retention rate (unit: %) was then calculated.

[0299] Tensile strength retention rate (%) = (Tensile strength after PCT 100-hour treatment / Initial tensile strength) × 100

[0300] The results are shown in Tables 3 and 4 below.

[0301] <Welding strength>

[0302] <<The Making of Resin Components>>

[0303] The light-transmitting resin composition (granules) obtained above was dried at 120°C for 7 hours, and then molded using an injection molding machine (Japan Steel Works Co., Ltd. "J55") at a barrel temperature of 260°C and a mold temperature of 60°C to produce... Figure 1 The molded article shown has a thickness of 1.5 mm (through resin component I).

[0304] <<Fabrication of Absorbent Resin Components>>

[0305] The light-absorbing resin granules obtained above were dried at 120°C for 7 hours, and then molded using an injection molding machine (Japan Steel Works Co., Ltd. "J55") at a barrel temperature of 260°C and a mold temperature of 60°C to produce... Figure 2 The molded part shown is (absorbent resin component II).

[0306] The resin component and the absorbent resin component, such as Figure 3 As shown, a cover-shaped permeable resin component I is superimposed on a box-shaped absorbent resin component II. A laser beam source is positioned vertically above the overlapping portion of the permeable resin component I and the absorbent resin component II, i.e., the flange portion. A pressing pressure of 4.92 N / mm (extrusion force during welding) is applied to the overlapping portion of the permeable resin component I and the absorbent resin component II from both sides in the thickness direction inward using a glass plate. Under the following conditions, a laser-welded product is obtained.

[0307] The welding apparatus is as described below.

[0308] <<Current Scanning Laser Welding>>

[0309] Laser device: IPG YLR-300-AC-Y14

[0310] Wavelength: 1070nm

[0311] Collimator: 7.5mm

[0312] Laser type: fiber

[0313] Laser power: 150W

[0314] Current scanner: Fiber Elephants 21 manufactured by ARGES

[0315] Aperture: 21mm

[0316] Laser irradiation speed: 900 mm / s

[0317] Laser irradiation cycles: 5 weeks or 20 weeks

[0318] Circumference of welded part: 137mm

[0319] The laser beam is defocused by using a spot diameter of 2mm to illuminate the welding surface, and the position of the laser scanner is adjusted accordingly.

[0320] <<Determination of Laser Welding Strength>>

[0321] like Figure 4 As shown, holes 21 and 22 are made respectively, so that clamps 23 and 24 for measuring welding force are placed inside. The measuring clamps 25 and 26 are inserted into the upper and lower surfaces of the box formed by the above-mentioned resin-permeable component I and resin-absorbing component II respectively, and are combined with the clamps 23 and 24 stored inside. The box is stretched up and down (stretching speed: 5 mm / min) to measure the strength of separation (welding strength) of resin-permeable component I and resin-absorbing component II.

[0322] It should be noted that the device uses a universal testing machine (load sensor 10kN) manufactured by ORIENTEC and 1t TENSILON.

[0323] The results are shown in Tables 3 and 4 below.

[0324] [Table 3]

[0325]

[0326] [Table 4]

[0327]

[0328] [Table 5]

[0329]

[0330] In Tables 3 and 4 above, LM section refers to the part that has undergone laser marking, and non-LM section refers to the part that has not undergone laser marking.

[0331] In Table 4, "×" indicates that laser welding was not performed.

[0332] The above results demonstrate that the molded article (through the resin component) formed from the resin composition of the present invention can be laser-marked and laser-welded (Examples 1-6). Furthermore, it is evident that the large color difference between the through-resin component and the laser-marked portion allows for effective laser marking. In addition, the through-resin component formed from the resin composition of the present invention exhibits high transmittance of light at a wavelength of 1060 nm, resulting in excellent laser transmittance. Furthermore, the aforementioned through-resin component maintains high strength even after pressure cooker testing. Moreover, the molded article (through the resin component) formed from the resin composition of this embodiment also exhibits a small color difference between the through-resin component and the absorbing resin component, resulting in excellent design flexibility. Furthermore, the large color difference between the laser-marked portion through the resin component and the absorbing resin component further enhances its design capabilities.

[0333] In contrast, in the case of polystyrene without butadiene rubber (Comparative Examples 1-3), the laser marking performance is poor. In addition, even in the case of polystyrene containing butadiene rubber, such as conventional laser marking resin compositions, if carbon black is included (Comparative Example 4), the laser cannot pass through, and it cannot be used as a laser-transmitting resin component during laser welding.

[0334] Explanation of reference numerals in the attached figures

[0335] Holes 21 and 22

[0336] 23, 24 Fixtures used for measurement

[0337] 25, 26 Fixtures for Measurement

Claims

1. A molded article formed from a resin composition, The resin composition is used as a laser-transmitting resin component during laser welding and can also be used for laser marking. The resin composition, relative to 100 parts by weight of thermoplastic polyester resin, comprises: 5-100 parts by weight of polystyrene containing butadiene rubber, 0.01-5 parts by weight of infrared-transmitting colorant, and 1-100 parts by weight of polycarbonate resin. The infrared-transmitting colorant is a black dye composition containing two or more colored dyes. When the resin composition is molded into a 1.5 mm thick test piece, the transmittance at a wavelength of 1064 nm is greater than 12%. When the resin composition is molded to a thickness of 1.5 mm and a portion is laser-marked, the color difference ΔE between the hue of the laser-marked portion and the hue of the non-laser-marked portion based on the SCE method is 7.0 or more. The thermoplastic polyester resin comprises polybutylene terephthalate resin. The butadiene-containing polystyrene is high-impact polystyrene (HIPS). The molded product was laser-marked.

2. The molded article according to claim 1, wherein, The polycarbonate resin comprises 1 to 500 parts by weight relative to 100 parts by weight of the butadiene-containing polystyrene.

3. The molded article according to claim 1, wherein, The resin composition also contains an epoxy compound.

4. The molded article according to claim 1, wherein, The resin composition also includes an inorganic filler.

5. The molded article according to claim 1, wherein, The resin composition also contains a phosphorus-based stabilizer.

6. The molded article according to claim 1, wherein, The nickel content in the infrared-transmitting colorant is less than 0.8% by mass.

7. The molded article according to claim 1, wherein, The content of pigments other than infrared-transmitting colorants in the resin composition is less than 1% by mass of the content of infrared-transmitting colorants.

8. The molded article according to claim 1, wherein, The content of aniline black in the resin composition is less than 1% by mass of the content of the infrared-transmitting colorant.

9. The molded article according to claim 1, wherein, When the resin composition is molded to a thickness of 1.5 mm and a portion of it is laser-marked, the color difference ΔE between the hue of the laser-marked portion and the hue of the non-laser-marked portion based on the SCE method is 10.0 or more.

10. A laser-welded article comprising a laser-transmitting resin component formed of a resin composition and a laser-absorbing resin component formed of a light-absorbing resin composition comprising a thermoplastic resin and a light-absorbing pigment. The resin composition is used as a laser-transmitting resin component during laser welding and can also be used for laser marking. The resin composition, relative to 100 parts by weight of thermoplastic polyester resin, comprises: 5-100 parts by weight of polystyrene containing butadiene rubber, 0.01-5 parts by weight of infrared-transmitting colorant, and 1-100 parts by weight of polycarbonate resin. The infrared-transmitting colorant is a black dye composition containing two or more colored dyes. When the resin composition is molded into a 1.5 mm thick test piece, the transmittance at a wavelength of 1064 nm is greater than 12%. When the resin composition is molded to a thickness of 1.5 mm and a portion is laser-marked, the color difference ΔE between the hue of the laser-marked portion and the hue of the non-laser-marked portion based on the SCE method is 7.0 or more. The thermoplastic polyester resin comprises polybutylene terephthalate resin. The butadiene-containing polystyrene is high-impact polystyrene (HIPS). In the laser-welded product, the laser-transmitting resin component was laser-marked.

11. The laser-welded article according to claim 10, wherein, The polycarbonate resin comprises 1 to 500 parts by weight relative to 100 parts by weight of the butadiene-containing polystyrene.

12. The laser-welded article according to claim 10, wherein, The resin composition also contains an epoxy compound.

13. The laser-welded article according to claim 10, wherein, The resin composition also includes an inorganic filler.

14. The laser-welded article according to claim 10, wherein, The resin composition also contains a phosphorus-based stabilizer.

15. The laser-welded article according to claim 10, wherein, The nickel content in the infrared-transmitting colorant is less than 0.8% by mass.

16. The laser-welded article according to claim 10, wherein, The content of pigments other than infrared-transmitting colorants in the resin composition is less than 1% by mass of the content of infrared-transmitting colorants.

17. The laser-welded article according to claim 10, wherein, The content of aniline black in the resin composition is less than 1% by mass of the content of the infrared-transmitting colorant.

18. The laser-welded article according to claim 10, wherein, When the resin composition is molded to a thickness of 1.5 mm and a portion of it is laser-marked, the color difference ΔE between the hue of the laser-marked portion and the hue of the non-laser-marked portion based on the SCE method is 10.0 or more.

19. A method for manufacturing a laser-welded article, comprising the following steps: Laser welding is performed on a laser-transmitting resin component and a laser-absorbing resin component formed from a light-absorbing resin composition comprising a thermoplastic resin and a light-absorbing pigment, wherein the laser-transmitting resin component is a molded article as described in any one of claims 1 to 9.

20. The method for manufacturing laser-welded articles according to claim 19, wherein, The laser welding is performed using current scanning laser welding.

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