Laser Welding Transparent Resin Composition, Molded Article, Kit, and Method for Producing Molded Article

Abstract

To provide a light transmissive resin composition for laser welding containing a polyamide resin whose 70 mol% or more of a diamine-derived structural unit is derived from xylylenediamine and 70 mol% or more of a dicarboxylic acid-derived structural unit is derived from an α,ω-straight-chain aliphatic dicarboxylic acid having 9 to 20 carbon atoms, which is low in light transmittance at a wave length of 700-800 nm and is high in light transmittance in the vicinity of a wavelength of 1,070 nm; and a molded article, a kit, a method for manufacturing a molded article, an on-board camera component, and an on-vehicle camera.SOLUTION: A light transmissive resin composition for laser welding contains, with respect to 100 pts.mass of a specific polyamide resin, 10-120 pts.mass of a reinforcement filler, 0.1-1.0 pts.mass of a light transmissive dye having a perylene skeleton, and at least one of copper iodide, potassium iodide and cerium oxide.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a light-transmissive resin composition for laser welding, a molded product, a kit, a method for manufacturing a molded product, in-vehicle camera parts, and an in-vehicle camera. The resin composition of the present invention is mainly used as a resin composition (light-transmissive resin composition) on the side that transmits light for laser welding.

[0002] Polyamide resin, which is a typical engineering plastic, is easy to process and furthermore has excellent mechanical properties, electrical properties, heat resistance, and other physical and chemical properties. For this reason, it is widely used in vehicle parts, electrical and electronic equipment parts, and other precision equipment parts. Recently, parts with complex shapes have also come to be manufactured using polyamide resin. For example, for the adhesion of parts having a hollow portion such as an intake manifold, various welding techniques such as adhesive welding, vibration welding, ultrasonic welding, hot plate welding, injection welding, and laser welding techniques are used.

[0003] However, welding with an adhesive has problems such as environmental load problems such as pollution of the surroundings in addition to the time loss until curing. Ultrasonic welding, hot plate welding, etc. have been pointed out to have problems such as damage to the product due to vibration and heat, and the need for post-treatment due to the generation of abrasion powder and burrs. In addition, injection welding often requires special molds and molding machines, and furthermore, there are problems such as it cannot be used if the fluidity of the material is not good.

[0004] On the one hand, laser welding is a method of joining two resin members by bringing a resin member having transparency (also referred to as non-absorbency or weak absorbency) to laser light (hereinafter sometimes referred to as a "transparent resin member") into contact with a resin member having absorbency to laser light (hereinafter sometimes referred to as an "absorbing resin member") and welding them. Specifically, it is a method of irradiating laser light from the transparent resin member side onto the joint surface to melt and join the absorbing resin member forming the joint surface with the energy of the laser light. Laser welding generates no abrasion powder or burrs, causes little damage to products, and furthermore, since the polyamide resin itself is a material with a relatively high laser transmittance, processing of polyamide resin products by laser welding technology has recently attracted attention.

[0005] The above-mentioned transparent resin member is usually formed from a light-transmissive resin composition. As such a light-transmissive resin composition, Patent Document 1 discloses a resin composition containing a semi-aromatic polyamide resin A, an aliphatic polyamide resin B, glass fibers, and a light-transmissive dye. The semi-aromatic polyamide resin A is composed of a structural unit derived from diamine and a structural unit derived from dicarboxylic acid. 70 mol% or more of the structural unit derived from diamine is derived from xylylenediamine, and 70 mol% or more of the structural unit derived from dicarboxylic acid is derived from an α,ω-linear aliphatic dicarboxylic acid having 8 to 20 carbon atoms. The aliphatic polyamide resin B contains at least one selected from polyamide 6 and polyamide 610, and the aliphatic polyamide resin B is contained in the resin composition at a ratio of 5 to 25% by mass, and the glass fibers are contained in the resin composition at a ratio of 25 to 60% by mass. A resin composition for laser welding is described.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Patent Document 1 describes the use of a polyamide resin composed of an α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms (e.g., sebacic acid) and xylylenediamine for laser welding. The polyamide resin composed of sebacic acid and xylylenediamine is a resin suitable for various properties required for laser welding, such as low water absorption rate. However, as a result of the inventor's investigation, it was found that it is easy to transmit light with a wavelength of 700 to 800 nm. Depending on the application, light with a wavelength of 700 to 800 nm is required to have a low light transmittance. On the other hand, for the resin composition for laser welding, it is necessary to maintain a high transmittance for the light for laser welding (e.g., light with a wavelength of around 1070 nm). An object of the present invention is to solve such problems, and there is provided a light-transmissive resin composition for laser welding containing a polyamide resin composed of an α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms (e.g., sebacic acid) and xylylenediamine, etc., which has a low light transmittance at a wavelength of 700 to 800 nm and a high light transmittance at a wavelength of around 1070 nm, as well as a molded article, a kit, a method for manufacturing a molded article, in-vehicle camera parts, and an in-vehicle camera.

Means for Solving the Problems

[0008] Based on the above problems, as a result of the inventor's investigation, by using a light-transmissive dye having a perylene skeleton as the light-transmissive dye and precisely adjusting its content, the above problems were solved. Specifically, the above problems were solved by the following means. <1> It contains 10 to 120 parts by mass of a reinforcing filler, 0.1 to 1.0 parts by mass of a light-transmissive dye having a perylene skeleton, and at least one of copper iodide, potassium iodide, and cerium oxide, based on 100 parts by mass of the polyamide resin. The polyamide resin is composed of a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 70 mol% or more of the structural unit derived from diamine is derived from xylylenediamine, and 70 mol% or more of the structural unit derived from dicarboxylic acid is derived from an α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms, a light-transmissive resin composition for laser welding. <2>The resin composition according to <1>, wherein the xylylenediamine contains 50 to 90 mol% of metaxylylenediamine and 10 to 50 mol% of paraxylylenediamine. <3>The resin composition according to <1> or <2>, wherein the α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms contains sebacic acid. <4>The resin composition according to <1>, wherein the xylylenediamine contains 50 to 90 mol% of metaxylylenediamine and 10 to 50 mol% of paraxylylenediamine, and the α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms contains sebacic acid. <5>The resin composition according to any one of <1> to <4>, wherein when the resin composition is formed into a test piece having a thickness of 1.0 mm, the light transmittance at a wavelength of 750 nm is 5% or less, and the light transmittance at a wavelength of 1070 nm is 20% or more. <6>The resin composition according to any one of <1> to <5>, wherein the content of the light-transmissive dye having a perylene skeleton is 0.1 to 0.5 parts by mass with respect to 100 parts by mass of the polyamide resin. <7>The resin composition according to any one of <1> to <5>, wherein the content of the light-transmissive dye having a perylene skeleton is 0.15 to 0.8 parts by mass with respect to 100 parts by mass of the polyamide resin. <8>A molded article formed from the resin composition according to any one of <1> to <7>. <9>A kit having the resin composition according to any one of <1> to <7>, a light-absorbing resin composition containing a thermoplastic resin and a light-absorbing dye. <10>A method for manufacturing a molded article, comprising laser-welding a molded article formed from the resin composition according to any one of <1> to <7> and a molded article formed from a light-absorbing resin composition containing a thermoplastic resin and a light-absorbing dye. An in-vehicle camera component formed from the resin composition according to any one of <11><1> to <7> or the kit according to <9>. An in-vehicle camera including the in-vehicle camera component according to <11>.

Advantages of the Invention

[0009] According to the present invention, a laser welding light-transmissive resin composition containing a polyamide resin in which 70 mol% or more of the structural units derived from diamine are derived from xylylenediamine and 70 mol% or more of the structural units derived from dicarboxylic acid are derived from α,ω-linear aliphatic dicarboxylic acids having 9 to 20 carbon atoms, which has a low light transmittance at a wavelength of 700 to 800 nm and a high light transmittance in the vicinity of a wavelength of 1070 nm, as well as a molded article, a kit, a method for manufacturing a molded article, an in-vehicle camera component, and an in-vehicle camera can be provided.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the following present embodiment is an exemplification for explaining the present invention, and the present invention is not limited to only the present embodiment. In this specification, "~" is used in the meaning of including the numerical values described before and after it as a lower limit value and an upper limit value. In this specification, various physical property values and characteristic values are those at 23°C unless otherwise specified. Note that "parts by mass" in this specification indicates the relative amount of components, and "mass%" indicates the absolute amount of components. When the standards shown in this specification differ depending on the year and the measurement method, etc., they are based on the standards as of January 1, 2020 unless otherwise specified.

[0011] The light-transmissive resin composition for laser welding according to the present embodiment (hereinafter sometimes simply referred to as "the resin composition of the present embodiment") contains, with respect to 100 parts by mass of a polyamide resin, 10 to 120 parts by mass of a reinforcing filler, 0.1 to 1.0 part by mass of a light-transmissive dye having a perylene skeleton, and at least one of copper iodide, potassium iodide, and cerium oxide. The polyamide resin is composed of a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 70 mol% or more of the structural unit derived from diamine is derived from xylylenediamine, and 70 mol% or more of the structural unit derived from dicarboxylic acid is derived from an α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms. By adopting such a configuration, it becomes possible to provide a resin composition having a low light transmittance at a wavelength of 700 to 800 nm and a high light transmittance in the vicinity of a wavelength of 1070 nm.

[0012] <Polyamide resin> The resin composition of the present embodiment includes, as the polyamide resin, one composed of a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 70 mol% or more of the structural unit derived from diamine is derived from xylylenediamine, and 70 mol% or more of the structural unit derived from dicarboxylic acid is derived from an α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms. Such a polyamide resin may be referred to as a xylylenediamine-based polyamide resin in this specification. In the present embodiment, by using a xylylenediamine-based polyamide resin, a resin composition capable of sufficiently exhibiting the performance required for laser welding can be obtained. Specifically, examples include the low water absorption rate of the xylylenediamine-based polyamide resin, the fact that the thermal shrinkage rate hardly varies depending on the mold temperature, etc., and the high mechanical strength.

[0013] In the xylylenediamine-based polyamide resin used in the present embodiment, preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and even more preferably 99 mol% or more of the structural unit derived from diamine is derived from xylylenediamine. The structural unit derived from xylylenediamine is preferably a structural unit derived from metaxylylenediamine and / or a structural unit derived from para-xylylenediamine, more preferably containing 50 to 90 mol% of metaxylylenediamine and 10 to 50 mol% of para-xylylenediamine (provided that the total does not exceed 100 mol%), and even more preferably containing 60 to 80 mol% of metaxylylenediamine and 20 to 40 mol% of para-xylylenediamine. In the xylylenediamine-based polyamide resin used in this embodiment, it is preferable that 95 mol% or more (preferably 99 mol% or more) of the structural unit derived from xylylenediamine is a structural unit derived from metaxylylenediamine and / or a structural unit derived from para-xylylenediamine.

[0014] Examples of diamines other than xylylenediamine that can be used as the raw material diamine component of the xylylenediamine-based polyamide resin include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, etc.; alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decalin, bis(aminomethyl)tricyclodecane, etc.; and diamines having an aromatic ring such as bis(4-aminophenyl)ether, paraphenylenediamine, bis(aminomethyl)naphthalene, etc. One kind or a mixture of two or more kinds can be used.

[0015] The xylylenediamine-based polyamide resin used in this embodiment has, in the constituent units derived from dicarboxylic acid, 70 mol% or more, preferably 75 mol% or more, more preferably 85 mol% or more, still more preferably 95 mol% or more, even more preferably 99 mol% or more, derived from α,ω-linear aliphatic dicarboxylic acids having 9 to 20 carbon atoms.

[0016] The α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms is preferably an α,ω-linear aliphatic dicarboxylic acid having 9 to 12 carbon atoms. Examples of the α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms include aliphatic dicarboxylic acids such as sebacic acid, undecanedioic acid, and dodecanedioic acid, and sebacic acid is more preferable. The α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms can be used alone or as a mixture of two or more.

[0017] Examples of the dicarboxylic acid component other than the above α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms include aliphatic dicarboxylic acids having less than 9 carbon atoms such as adipic acid, phthalic acid compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and isomers of naphthalenedicarboxylic acid such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, and these can be used alone or as a mixture of two or more.

[0018] In the xylylenediamine-based polyamide resin, the xylylenediamine as a raw material contains 50 to 90 mol% of metaxylylenediamine and 10 to 50 mol% of para-xylylenediamine, and it is preferable that the α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms contains sebacic acid. More preferably, 90 mol% or more of the raw material diamine is xylylenediamine, the xylylenediamine contains 99 mol% or more in total of 60 to 80 mol% of metaxylylenediamine and 40 to 20 mol% of para-xylylenediamine, and 90 mol% or more of the α,ω-linear aliphatic dicarboxylic acid is sebacic acid.

[0019] The xylylenediamine-based polyamide resin is composed mainly of a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, but does not completely exclude structural units other than these, and it goes without saying that it may contain structural units derived from lactams such as ε-caprolactam and laurolactam, and aliphatic aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid. Here, the main component means that among the structural units constituting the xylylenediamine-based polyamide resin, the total number of the structural unit derived from a diamine and the structural unit derived from a dicarboxylic acid is the largest among all the structural units. In the present embodiment, the total of the structural unit derived from a diamine and the structural unit derived from a dicarboxylic acid in the xylylenediamine-based polyamide resin preferably occupies 90% or more of all the structural units, and more preferably occupies 95% or more.

[0020] The resin composition of the present embodiment preferably contains the polyamide resin at a ratio of 30% by mass or more of the resin composition, more preferably at a ratio of 35% by mass or more, further preferably at a ratio of 40% by mass or more, and still more preferably at a ratio of 45% by mass or more. Also, the upper limit value of the content of the polyamide resin is preferably 80% by mass or less, and more preferably 75% by mass or less. The polyamide resin may contain only one kind or two or more kinds. When two or more kinds are contained, the total amount is preferably within the above range.

[0021] <Reinforcing filler> The resin composition of this embodiment contains a reinforcing filler in a proportion of 10 to 120 parts by mass with respect to 100 parts by mass of the xylylenediamine-based polyamide resin. By containing the reinforcing filler in the above proportion, high mechanical strength can be achieved. It should be noted that the reinforcing filler in this embodiment does not include cerium oxide and those corresponding to nucleating agents described later. The reinforcing filler that can be contained and used in the resin composition of this embodiment has the effect of improving the mechanical properties of the resin composition obtained by blending it with the resin, and common plastic reinforcing materials can be used. The reinforcing filler may be an organic substance or an inorganic substance, but an inorganic substance is preferred. As the reinforcing filler, fibrous reinforcing fillers such as glass fiber, carbon fiber, basalt fiber, wollastonite, and potassium titanate fiber can preferably be used. Also, fillers such as calcium carbonate, titanium oxide, feldspar minerals, clay, organic clay, and glass beads; and flaky reinforcing materials such as glass flakes, mica, and graphite can be used. Among them, from the viewpoints of mechanical strength, rigidity, and heat resistance, it is preferable to use fibrous reinforcing fillers, particularly glass fiber. As the glass fiber, either a round cross-sectional shape or an irregular cross-sectional shape can be used. It is more preferable to use a reinforcing filler that has been surface-treated with a surface treatment agent such as a coupling agent. Glass fiber with a surface treatment agent attached is preferable because it is excellent in durability, heat and humidity resistance, hydrolysis resistance, and heat shock resistance.

[0022] The glass fiber is composed of a glass composition such as A glass, C glass, E glass, S glass, R glass, M glass, D glass, boron-free glass (glass with a boron ratio of 30 mass ppm or less), and particularly, E glass (alkali-free glass) is preferable. The glass fiber refers to a fiber having a circular, elliptical, flat, oblong, or polygonal cross-sectional shape when cut perpendicular to the length direction and presenting a fibrous appearance.

[0023] The glass fiber used in the resin composition of this embodiment may be a single fiber or a plurality of single fibers twisted together. The form of the glass fiber may be any of "glass roving" obtained by continuously winding a single fiber or a plurality of twisted single fibers, "chopped strand" cut to a length of 1 to 10 mm, "milled fiber" ground to a length of 10 to 500 μm, etc. Such glass fibers are commercially available under the trade names of "Glassron Chopped Strand" and "Glassron Milled Fiber" from Asahi Fiber Glass Co., Ltd. and are easily available. Glass fibers with different forms can also be used in combination.

[0024] In addition, the cross-section of the glass fiber used in this embodiment may be circular or non-circular. By using glass fibers with a non-circular cross-section, the warpage of the resulting molded product can be more effectively suppressed. Also, in this embodiment, even when using glass fibers with a circular cross-section, the warpage can be effectively suppressed.

[0025] The content of the reinforcing filler in the resin composition of this embodiment is 10 parts by mass or more, more preferably 20 parts by mass or more, still more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, based on 100 parts by mass of the xylylenediamine-based polyamide resin. Regarding the upper limit value, it is 120 parts by mass or less, more preferably 110 parts by mass or less, based on 100 parts by mass of the xylylenediamine-based polyamide resin. The content of the reinforcing filler 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. Regarding the upper limit value, it is preferably 70% by mass or less, more preferably 65% by mass or less, still more preferably 60% by mass or less, and even more preferably 55% by mass or less. The resin composition of this embodiment may contain only one kind of reinforcing filler or two or more kinds. When two or more kinds are contained, the total amount is within the above range. Note that the content of the reinforcing filler in this embodiment is intended to include the amounts of the sizing agent and the surface treatment agent.

[0026] <Light-transmissive dye having a perylene skeleton> The resin composition of this embodiment contains a light-transmissive dye having a perylene skeleton in a proportion of 0.1 to 1.0 parts by mass with respect to 100 parts by mass of the xylylenediamine-based polyamide resin. By blending a light-transmissive dye having a perylene skeleton, a resin composition can be obtained that has a low light transmittance at a wavelength of 700 to 800 nm and a high light transmittance in the vicinity of a wavelength of 1070 nm while using the xylylenediamine-based polyamide resin. The light-transmissive dyes used in this embodiment are black dyes, black-purple dyes, etc. These light-transmissive dyes are dyes that appear black to the human eye. Also, the light-transmissive dye refers to, for example, a dye that, when blended so that the total of the polyamide resin, 30% by mass of glass fiber, and 0.2% by mass of the dye (a dye considered to be a light-transmissive dye) is 100% by mass, has a light transmittance of 20% or more when measured at a wavelength of 1070 nm by the measurement method described in the examples below. The light-transmissive dye may be a dye or a pigment, but a pigment is preferred. Examples of the dye having a perylene skeleton include Spectrasence (registered trademark) Black K0087 (former: Lumogen (registered trademark) Black FK4280), Spectrasence Black K0088 (former: Lumogen Black FK4281), etc., manufactured by BASF Color & Effect Japan Co., Ltd.

[0027] The resin composition of this embodiment contains 0.1 part by mass or more, preferably 0.15 part by mass or more, more preferably 0.18 part by mass or more, still more preferably 0.20 part by mass or more, and even more preferably 0.25 part by mass or more, or 0.4 part by mass or more of a light-transmissive dye having a perylene skeleton with respect to 100 parts by mass of the xylylenediamine-based polyamide resin. Also, the resin composition of this embodiment contains 1.0 part by mass or less, preferably 0.8 part by mass or less, more preferably 0.7 part by mass or less, and may be 0.5 part by mass or less of a light-transmissive dye having a perylene skeleton with respect to 100 parts by mass of the xylylenediamine-based polyamide resin. By precisely adjusting the blending amount of the light-transmissive dye having a perylene skeleton in this way, light of a desired wavelength can be selectively transmitted. The resin composition of this embodiment may contain only one kind of light-transmissive dye having a perylene skeleton, or may contain two or more kinds. When two or more kinds are contained, it is preferable that the total amount is within the above range. The resin composition of this embodiment may contain other dyes other than the light-transmissive dye having a perylene skeleton, but it is preferably substantially free of them. Substantially free means, for example, that the content of other dyes is less than 1% by mass of the content of the light-transmissive dye having a perylene skeleton.

[0028] <Copper iodide, potassium iodide, and cerium oxide> The resin composition of this embodiment contains at least one of copper iodide, potassium iodide, and cerium oxide. By containing copper iodide, the heat resistance of the obtained molded product tends to be further improved. Also, by containing potassium iodide, it becomes easier to form a complex in the polyamide resin, and the decomposition of the resin can be more effectively suppressed. Furthermore, by containing cerium oxide, the original color is beige, and there is little color change even when added to natural or light-colored materials, and the color change due to oxidation can be reduced. That is, by blending these components, it becomes possible to impart performance according to the application.

[0029] The proportion of copper iodide in the resin composition of the present embodiment is preferably 0.01 to 1% by mass, more preferably 0.02% by mass or more, and even more preferably 0.5% by mass or less, and still more preferably 0.3% by mass or less in the resin composition. The resin composition of the present embodiment may contain only one kind of copper iodide or two or more kinds of copper iodide. When two or more kinds are contained, the total amount is preferably within the above range. The proportion of potassium iodide in the resin composition of the present embodiment is preferably 0.01 to 2% by mass, more preferably 0.02% by mass or more, and even more preferably 1% by mass or less in the resin composition. The proportion of cerium oxide in the resin composition of the present embodiment is preferably 0.01 to 2% by mass, more preferably 0.02% by mass or more, and even more preferably 1% by mass or less in the resin composition. The resin composition of the present embodiment may contain only one kind of cerium oxide or two or more kinds of cerium oxide. When two or more kinds are contained, the total amount is preferably within the above range.

[0030] <Release agent> The resin composition of the present embodiment may contain a release agent. Examples of the release agent include aliphatic carboxylic acids, salts of aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15,000, polysiloxane-based silicone oils, ketone waxes, light amides, etc. Aliphatic carboxylic acids, salts of aliphatic carboxylic acids, and esters of aliphatic carboxylic acids and alcohols are preferred, and salts of aliphatic carboxylic acids are more preferred. Details of the release agent can be referred to the descriptions in paragraphs 0055 to 0061 of JP-A-2018-095706, and these contents are incorporated herein. When the resin composition of the present embodiment contains a release agent, its content is preferably 0.05 to 3% by mass, more preferably 0.1 to 0.8% by mass, and still more preferably 0.2 to 0.6% by mass in the resin composition. The resin composition of this embodiment may contain only one type of release agent or two or more types of release agents. When two or more types are contained, it is preferable that the total amount is within the above range.

[0031] <Nucleating agent> The resin composition of this embodiment may contain a nucleating agent. The nucleating agent is not particularly limited as long as it is undissolved during melt processing and can serve as a crystal nucleus during the cooling process. Among them, talc and calcium carbonate are preferable, and talc is more preferable. The number average particle diameter of the nucleating agent preferably has a lower limit of 0.1 μm or more, more preferably 1 μm or more, and even more preferably 3 μm or more. The number average particle diameter of the nucleating agent preferably has an upper limit of 40 μm or less, more preferably 30 μm or less, even more preferably 28 μm or less, still more preferably 15 μm or less, and even still more preferably 10 μm or less.

[0032] The proportion of the nucleating agent in the resin composition of this embodiment is preferably 0.01 to 1% by mass, more preferably 0.1% by mass or more, and more preferably 0.5% by mass or less. The resin composition of this embodiment may contain only one type of nucleating agent or two or more types of nucleating agents. When two or more types are contained, it is preferable that the total amount is within the above range.

[0033] <Other components> The resin composition of this embodiment may contain other components without departing from the gist of the present invention. Such additives include light stabilizers, antioxidants, ultraviolet absorbers, fluorescent brighteners, anti-dripping agents, antistatic agents, anti-fogging agents, anti-blocking agents, fluidity improvers, plasticizers, dispersants, antibacterial agents, flame retardants, etc. Further, the resin composition of this embodiment may contain copper compounds other than copper iodide, alkali metal halides other than potassium iodide, etc. These components may be used alone or in combination of two or more. In addition, for the resin composition of the present embodiment, the total of each component is 100% by mass, and the content of xylylenediamine-based polyamide resin, reinforcing filler, light-transmissive dye having a perylene skeleton, at least one of copper iodide, potassium iodide, and cerium oxide, and further other additives is adjusted. In the present embodiment, an aspect is exemplified in which the total of xylylenediamine-based polyamide resin, reinforcing filler, light-transmissive dye having a perylene skeleton, at least one of copper iodide, potassium iodide, and cerium oxide, nucleating agent, and mold release agent occupies 99% by mass or more of the resin composition.

[0034] <Physical properties of the resin composition> The resin composition of the present embodiment is required to have a low light transmittance at a wavelength of 700 to 800 nm and a high light transmittance near a wavelength of 1070 nm. For example, when the resin composition of the present embodiment is formed into a test piece with a thickness of 1.0 mm, the light transmittance at a wavelength of 750 nm is 10% or less (preferably 5% or less, more preferably 0 to 3%, still more preferably 0 to 2%, even more preferably 0 to 1%), and the light transmittance at a wavelength of 1070 nm is preferably 20% or more. The light transmittance at the wavelength of 1070 nm is preferably 30% or more, more preferably 40% or more, and even more preferably 50% or more. In addition, when the resin composition of the present embodiment is formed into a test piece with a thickness of 1.0 mm, the light transmittance at a wavelength of 800 nm is 9% or less (preferably 7% or less, more preferably 5% or less, still more preferably 0 to 3%, even more preferably 0 to 2%, even more preferably 0 to 1%), and the light transmittance at a wavelength of 1070 nm is preferably 20% or more. The upper limit of the light transmittance at the wavelength of 1070 nm is preferably as high as possible. For example, it may be 90% or less, or may be 70% or less. The light transmittance is measured according to the description of the examples described later.

[0035] The resin composition of the present embodiment preferably has excellent bending properties. Specifically, when the resin composition of the present embodiment is formed into an ISO tensile test piece with a thickness of 4 mm, the flexural strength conforming to ISO 178 is preferably 200 MPa or more, more preferably 210 MPa or more, and even more preferably 230 MPa or more. Also, when the resin composition of the present embodiment is formed into an ISO tensile test piece with a thickness of 4 mm, the upper limit of the flexural strength conforming to ISO 178 is not particularly defined, but for example, it is 50 MPa or less, and even 380 MPa or less is sufficient to meet the required performance. Also, when the resin composition of the present embodiment is formed into an ISO tensile test piece with a thickness of 4 mm, the flexural modulus conforming to ISO 178 is preferably 8000 MPa or more, more preferably 8500 MPa or more, and even more preferably 9000 MPa or more. Also, when the resin composition of the present embodiment is formed into an ISO tensile test piece with a thickness of 4 mm, the upper limit of the flexural strength conforming to ISO 178 is not particularly defined, but for example, it is 20000 MPa or less, and even 19000 MPa or less is sufficient to meet the required performance.

[0036] <Manufacturing method of resin composition> The manufacturing method of the resin composition of the present embodiment is not particularly limited, but a method using a single-screw or twin-screw extruder having a facility capable of devolatilization from a vent port as a kneader is preferred. The above polyamide resin component, reinforcing filler, light-transmissive pigment, copper iodide, potassium iodide, and at least one of cerium oxide, and other additives blended as required may be supplied to the kneader all at once, or after supplying the polyamide resin component, other compounding components may be supplied sequentially. The reinforcing filler is preferably supplied from the middle of the extruder in order to suppress crushing during kneading. Also, two or more components selected from each component may be premixed and kneaded in advance. In the present embodiment, the light-transmissive pigment may be prepared in advance as a masterbatch with a polyamide resin or the like, and then kneaded with other components (at least one of a polyamide resin component, a reinforcing filler, a light-transmissive pigment, copper iodide, potassium iodide, and cerium oxide, etc.) to obtain the resin composition in the present embodiment.

[0037] The manufacturing method of the molded article using the resin composition of the present embodiment is not particularly limited, and molding methods generally used for thermoplastic resins, that is, injection molding, blow molding, extrusion molding, press molding, and other molding methods can be applied. In this case, the particularly preferred molding method is injection molding because of its good fluidity. When performing injection molding, it is preferable to control the resin temperature at 250 to 300°C.

[0038] <Kit> The resin composition of the present embodiment and the light-absorbing resin composition containing a thermoplastic resin and a light-absorbing dye are preferably used as a kit for manufacturing a molded article (laser-welded article) by laser welding. That is, the resin composition of the present embodiment contained in the kit serves as a light-transmissive resin composition, and the molded article formed from such a light-transmissive resin composition becomes a transmissive resin member with respect to the laser light during laser welding. On the other hand, the molded article formed from the light-absorbing resin composition becomes an absorbing resin member with respect to the laser light during laser welding.

[0039] <<Light-absorbing resin composition>> The light-absorbing resin composition used in the present embodiment contains a thermoplastic resin and a light-absorbing dye. Further, it may contain other components such as a reinforcing filler. Examples of the thermoplastic resin include polyamide resin, olefin resin, vinyl resin, styrene resin, acrylic resin, polyphenylene ether resin, polyester resin, polycarbonate resin, polyacetal resin, etc. From the viewpoint of good compatibility with the light-transmissive resin composition (the resin composition of the present embodiment), particularly, polyamide resin, polyester resin, and polycarbonate resin are preferable, and polyamide resin is more preferable. Also, the thermoplastic resin may be one kind or two or more kinds. The type of the polyamide resin used in the light-absorbing resin composition is not defined, but the above-mentioned xylylenediamine-based polyamide resin is preferable. Reinforcing fillers include fillers capable of absorbing laser light, such as glass fibers, carbon fibers, silica, alumina, carbon black, and inorganic powders coated with a material that absorbs a laser, such as a laser. Glass fibers are preferred. The glass fibers are synonymous with the glass fibers that may be blended in the resin composition of the present embodiment. The content of the reinforcing filler is preferably 20 to 70% by mass, more preferably 25 to 60% by mass, and still more preferably 30 to 55% by mass. As the light-absorbing dye, dyes having an absorption wavelength in the range of the laser light wavelength to be irradiated, for example, in the present embodiment, in the range of 900 nm to 1100 nm, are included. In addition, as the light-absorbing dye, for example, 0.3 parts by mass is blended with respect to 100 parts by mass of the xylylenediamine-based polyamide resin, and when the light transmittance is measured by the measurement method described in the examples described later, dyes having a transmittance of less than 30%, and further 10% or less are included. Specific examples of the light-absorbing dye include inorganic pigments (black pigments such as carbon black (for example, acetylene black, lamp black, thermal black, furnace black, channel black, ketjen black, etc.), red pigments such as iron oxide red, orange pigments such as molybdate orange, white pigments such as titanium oxide), organic pigments (yellow pigments, orange pigments, red pigments, blue pigments, green pigments, etc.). Among them, inorganic pigments are generally preferred because of their strong hiding power, and black pigments are more preferred. These light-absorbing dyes may be used in combination of two or more. The content of the light-absorbing dye is preferably 0.01 to 30 parts by mass with respect to 100 parts by mass of the xylylenediamine-based polyamide resin.

[0040] Regarding the components excluding the light-transmitting dye and the reinforcing filler in the resin composition and the components excluding the light-absorbing dye and the reinforcing filler in the light-absorbing resin composition, it is preferable that 80% by mass or more is common, more preferably 90% by mass or more is common, and still more preferably 95 to 100% by mass is common.

[0041] <<Laser Welding Method>> Next, the laser welding method will be described. In the present embodiment, a molded article (transparent resin member) formed from the resin composition of the present embodiment and a molded article (absorbing resin member) formed by molding the above light-absorbing resin composition can be laser welded to produce a molded article. By laser welding, the transparent resin member and the absorbing resin member can be firmly welded without using an adhesive. The shape of the members is not particularly limited. However, since the members are joined by laser welding for use, they usually have a shape having at least a surface contact portion (plane, curved surface). In laser welding, the laser light transmitted through the transparent resin member is absorbed by the absorbing resin member, melted, and the two members are welded. Since the molded article formed from the resin composition of the present embodiment has high transparency to laser light, it can be preferably used as a transparent resin member. Here, the thickness of the member through which the laser light passes (the thickness in the laser transmission direction in the portion where the laser light passes) can be appropriately determined in consideration of the application, the composition of the resin composition, and the like. For example, it is 5 mm or less, preferably 4 mm or less.

[0042] The laser light source used for laser welding can be determined according to the light absorption wavelength of the light-absorbing dye. A laser in the wavelength range of 900 to 1100 nm is preferred. For example, a semiconductor laser or a fiber laser can be used.

[0043] More specifically, for example, when welding a transparent resin member and an absorbing resin member, first, the welding portions of the two are brought into contact with each other. At this time, surface contact is desirable for the welding portions of the two, and they may be a combination of planes, curved surfaces, or a plane and a curved surface. Next, laser light is irradiated from the transparent resin member side. At this time, a lens may be used to condense the laser light at the interface between the two if necessary. The condensed beam passes through the transparent resin member, is absorbed near the surface of the absorbing resin member, generates heat, and melts. Next, the heat is also transmitted to the transparent resin member by heat conduction and melts, forming a molten pool at the interface between the two. After cooling, the two are joined. The molded product obtained by welding the transparent resin member and the absorbent resin member in this way has high welding strength. Note that the molded product in the present embodiment includes not only the finished product and parts but also the members that form a part of these.

[0044] The molded product obtained by laser welding in this embodiment has good mechanical strength, high welding strength, and little damage to the resin due to laser irradiation. Therefore, it can be applied to various uses, for example, various storage containers, electrical and electronic equipment parts, office automation (OA) equipment parts, household appliance parts, mechanical mechanism parts, vehicle mechanism parts, etc. In particular, it can be suitably used for food containers, medicine containers, oil and fat product containers, vehicle hollow parts (various tanks, intake manifold parts, camera housings, etc.), vehicle electrical parts (various control units, ignition coil parts, etc.), motor parts, various sensor parts, connector parts, switch parts, breaker parts, relay parts, coil parts, transformer parts, lamp parts, etc. In particular, the in-vehicle camera parts formed from the resin composition and kit of the present embodiment are suitable for in-vehicle cameras.

Examples

[0045] The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. When the measuring instruments used in the examples are difficult to obtain due to obsolescence or the like, measurements can be made using other instruments having equivalent performance.

[0046] <Polyamide resin> MP10: M / P molar ratio = 7:3, synthesized according to the following synthesis example. <<Synthesis example of MP10 (M / P molar ratio = 7:3)>> Sebacic acid was heated and dissolved in a reaction vessel under a nitrogen atmosphere. After that, while stirring the contents, a mixed diamine with a molar ratio of 3:7 of para-xylylenediamine (manufactured by Mitsubishi Gas Chemical Company) and meta-xylylenediamine (manufactured by Mitsubishi Gas Chemical Company) was gradually dropped under pressure (0.35 MPa) while raising the temperature to 235 °C so that the molar ratio of diamine to sebacic acid became about 1:1. After the dropping was completed, the reaction was continued for 60 minutes to adjust the amount of components with a molecular weight of 1,000 or less. After the reaction was completed, the contents were taken out in a strand shape and pelletized with a pelletizer to obtain a polyamide resin (MP10, M / P molar ratio = 7:3).

[0047] <Talc> #5000S: Manufactured by Hayashi Kasei Co., Ltd., micron white <Stabilizer> Yoka Daiichidou: Manufactured by Nippon Chemical Industry Co., Ltd., cuprous iodide Potassium iodide: Manufactured by Fujifilm Wako Pure Chemical Corporation Zinc stearate (II): Manufactured by Fujifilm Wako Pure Chemical Corporation <Cerium oxide> Cerium Hydrate90, Manufactured by TREIBACHER INDUSTRIE AG

[0048] <Reinforcing filler (glass fiber)> ECS03T-211H: Manufactured by Nippon Electric Glass Co., Ltd., single fiber diameter 10.5 μm, length 3.5 mm, circular cross-section

[0049] <Release agent> CS8CP: Manufactured by Nitto Kasei Kogyo Co., Ltd., montanic acid soap

[0050] <Light-transmitting pigment> Spectrasence Black K0088: Manufactured by BASF Color & Effect Japan Co., Ltd., perylene pigment, Spectrasence Black K0088 (former Lumogen Black K 0088, former Lumogen Black FK 4281)

[0051] Examples 1 to 8, Comparative Examples 1 to 4 <Compound> The components other than glass fiber were weighed and dry-blended so as to have the composition shown in Table 1 or Table 2 described below (each component in Table 1 or Table 2 is expressed in parts by mass). After that, they were introduced from the screw root of a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd. (currently: Shibaura Machine Co., Ltd.), TEM26SS) using a twin-screw type cassette weighing feeder (manufactured by Kubota Corporation, CE-W-1-MP). For the glass fiber, it was introduced into the above-mentioned twin-screw extruder from the side of the extruder using a vibratory cassette weighing feeder (manufactured by Kubota Corporation, CE-V-1B-MP), and melt-kneaded with the resin components etc. to obtain resin composition pellets. The temperature setting of the extruder was 280°C.

[0052] <Flexural strength and flexural modulus> After drying the resin pellets obtained by the above manufacturing method at 120°C for 4 hours, using NEX140III manufactured by Nissei Plastic Industrial Co., Ltd., an ISO tensile test piece with a thickness of 4 mm was injection-molded. At the time of molding, the cylinder temperature was 280°C and the mold temperature was 130°C. In accordance with ISO178, using the above ISO tensile test piece (4 mm thick), the flexural strength (unit: MPa) and flexural modulus (unit: MPa) were measured at a temperature of 23°C.

[0053] <Light transmittance> After drying the resin composition pellets obtained above at 120°C for 4 hours, using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., SE-50D), a test piece (1.0 mm thick) for measuring light transmittance was produced. The light transmittance was measured using a visible / ultraviolet spectrophotometer (manufactured by Shimadzu Corporation, UV-3100PC), and the light transmittance (unit: %) at each wavelength shown in Table 1 or Table 2 was measured respectively.

[0054]

Table 1

Table 2

[0055] As is clear from the above results, the resin compositions described in Examples 1 to 8 had a high light transmittance at a wavelength of 1070 nm and a low light transmittance at wavelengths of 700 to 800 nm. Furthermore, the mechanical strength could also be maintained at a high level. On the other hand, when the blending amount of the light-transmissive dye was less than 0.1 part by mass (Comparative Examples 1 to 4), the light transmittance at wavelengths of 700 to 800 nm was high.

[0056] Regarding the resin composition of Example 1, an absorption resin member forming pellet was obtained in the same manner except that no light-transmissive dye was blended and 3 parts by mass of a carbon black masterbatch (carbon black #45 manufactured by Mitsubishi Chemical Corporation) was blended. Using the pellet obtained in Example 1 and the absorption resin member forming pellet, laser welding was performed according to the descriptions in paragraphs 0072 and 0073 of JP-A-2018-168346 and FIG. 1. It was confirmed that laser welding was appropriately performed.

Claims

1. It contains 10 to 120 parts by mass of a reinforcing filler, 0.15 to 1.0 part by mass of a light-transmitting dye having a perylene skeleton, and at least one of copper iodide, potassium iodide, and cerium oxide, based on 100 parts by mass of the polyamide resin. The polyamide resin is composed of a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, and 70 mol% or more of the structural unit derived from the diamine is derived from xylylenediamine, and 70 mol% or more of the structural unit derived from the dicarboxylic acid is derived from an α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms. A light-transmitting resin composition for laser welding.

2. The resin composition according to claim 1, wherein the xylylenediamine contains 50 to 90 mol% of metaxylylenediamine and 10 to 50 mol% of p-xylylenediamine.

3. The resin composition according to claim 1 or 2, wherein the α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms contains sebacic acid.

4. The resin composition according to claim 1, wherein the xylylenediamine contains 50 to 90 mol% of metaxylylenediamine and 10 to 50 mol% of p-xylylenediamine, and the α,ω-linear aliphatic dicarboxylic acid having 9 to 20 carbon atoms contains sebacic acid.

5. When the resin composition is formed into a test piece having a thickness of 1.0 mm, the light transmittance at a wavelength of 750 nm is 5% or less, and the light transmittance at a wavelength of 1070 nm is 20% or more. The resin composition according to any one of claims 1 to 4.

6. The resin composition according to any one of claims 1 to 5, wherein the content of the light-transmitting dye having a perylene skeleton is 0.15 to 0.5 part by mass based on 100 parts by mass of the polyamide resin.

7. The resin composition according to any one of claims 1 to 5, wherein the content of the light-transmitting dye having a perylene skeleton is 0.15 to 0.8 part by mass based on 100 parts by mass of the polyamide resin.

8. A molded article formed from the resin composition according to any one of claims 1 to 7.

9. A kit comprising the resin composition according to any one of claims 1 to 7 and a light-absorbing resin composition containing a thermoplastic resin and a light-absorbing dye.

10. A method for manufacturing a molded article, comprising laser-welding a molded article formed from the resin composition according to any one of claims 1 to 7 and a molded article formed from a light-absorbing resin composition containing a thermoplastic resin and a light-absorbing dye.

11. An in-vehicle camera component formed from the resin composition according to any one of claims 1 to 7 or the kit according to claim 9.

12. An in-vehicle camera comprising the in-vehicle camera component according to claim 11.

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