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

Abstract

Provided is a light-transmissive resin composition for laser welding with which color migration of a coloring agent to other components is suppressed. Also provided are a kit, a molded product, and a method for producing a molded product. This light-transmissive resin composition for laser welding comprises, per 100 parts by mass of a crystalline thermoplastic resin: 10-120 parts by mass of a reinforcing filler; 0.01-1.0 parts by mass of a light-transmissive dye having a perylene skeleton; and at least one type of compound selected from copper compounds, alkali metal halides, and cerium oxide.

Description

Technical Field

[0001] The present invention relates to a light-transmissive resin composition for laser welding, a kit, a molded article, and a method for manufacturing the molded article.

Background Art

[0002] Thermoplastic resins are easy to process and are widely used in vehicle parts, electrical and electronic equipment parts, and other precision equipment parts by taking advantage of their excellent properties. Recently, parts with complex shapes have also come to be manufactured using thermoplastic resins, especially crystalline thermoplastic resins. For the adhesion of parts having a hollow part such as an intake manifold, various welding techniques are used, specifically, adhesive welding, vibration welding, ultrasonic welding, hot plate welding, injection welding, laser welding techniques, and the like.

[0003] However, welding with an adhesive has problems such as environmental load problems such as ambient contamination 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 further has problems such as not being able to be used if the fluidity of the material is not good.

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

[0005] The above-mentioned light-transmitting resin member is usually obtained by molding a light-transmitting resin composition. As such a light-transmitting resin composition, Patent Document 1 discloses a resin composition obtained by blending (A) 100 parts by mass of a polyamide resin with (B) 1 to 150 parts by mass of a reinforcing filler having a refractive index of 1.560 to 1.600 at 23°C, wherein at least one monomer constituting at least one of the (A) polyamide resins contains an aromatic ring, and a resin composition for laser welding is described. In the examples of Patent Document 1, a resin composition in which glass fiber and a colorant are blended with a blend of polyamide MXD6 and polyamide 66, or a blend of polyamide 6I / 6T and polyamide 6 is disclosed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Here, as the laser welding technology progresses, there is a growing demand for new materials. In particular, a material that can suppress the color transfer of the light-transmitting dye in the light-transmitting resin member to other members (peripheral members) after laser welding is required. An object of the present invention is to solve such problems, and to provide a light-transmitting resin composition for laser welding in which the color transfer of the colorant to other members is suppressed, as well as a kit, a molded product, and a method for manufacturing the molded product.

Means for Solving the Problems

[0008] As a result of the study by the present inventors under the above problems, the above problems were solved by using a light-transmitting dye having a perylene skeleton as the light-transmitting dye. Specifically, the above problems were solved by the following means. <1>A light-transmissive resin composition for laser welding, comprising 100 parts by mass of a crystalline thermoplastic resin, 10 to 120 parts by mass of a reinforcing filler, 0.01 to 1.0 part by mass of a light-transmissive dye having a perylene skeleton, and at least one of a copper compound, an alkali metal halide, and cerium oxide. <2>The resin composition according to <1>, wherein the content of lanthanum in the resin composition is more than 0 ppm by mass and 40 ppm by mass or less. <3>The resin composition according to <1> or <2>, comprising cerium oxide in which the content of lanthanum measured by ICP emission spectrometry is more than 0% by mass and 1% by mass or less. <4>The resin composition according to any one of <1> to <3>, wherein the content of the cerium oxide is 0.01 to 5% by mass in the resin composition. <5>The resin composition according to any one of <1> to <4>, wherein the crystalline thermoplastic resin contains a polyamide resin. <6>The polyamide resin is composed of a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and the resin composition according to <5>, comprising a polyamide resin in which 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 4 to 20 carbon atoms. <7>The resin composition according to any one of <1> to <6>, wherein the light-transmissive dye having a perylene skeleton is a pigment. <8>A kit having the resin composition according to any one of <1> to <7> and a light-absorbing resin composition containing a thermoplastic resin and a light-absorbing dye. <9>A molded article formed from the resin composition according to any one of <1> to <7> or the kit according to <8>. <10>The molded article according to <9>, which is an in-vehicle camera component. <11>An in-vehicle camera including the molded article according to <10>. <12>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.

Advantages of the Invention

[0009] According to the present invention, it has become possible to provide a laser-welding light-transmissive resin composition in which color transfer of a colorant to other members is suppressed, as well as a kit, a molded article, and a method for manufacturing the molded article.

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 only to the present embodiment. In this specification, "~" is used in the sense 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. In this specification, ppm means mass ppm.

[0011] The laser-welding light-transmissive resin composition of the present embodiment (hereinafter sometimes simply referred to as "the resin composition") contains 10 to 120 parts by mass of a reinforcing filler, 0.01 to 1.0 part by mass of a light-transmissive dye having a perylene skeleton, and at least one of a copper compound, an alkali metal halide, and cerium oxide with respect to 100 parts by mass of a crystalline thermoplastic resin. By adopting such a configuration, color transfer of the light-transmissive dye to other members can be effectively suppressed. The resin composition of the present embodiment preferably contains at least cerium oxide among a copper compound, an alkali metal halide, and cerium oxide.

[0012] <Crystalline Thermoplastic Resin> The resin composition of the present embodiment contains a crystalline thermoplastic resin. By using a crystalline thermoplastic resin, a resin composition having the performance required for laser welding that the crystalline thermoplastic resin inherently has can be obtained. Specifically, examples include the low water absorption rate of the crystalline thermoplastic resin, the fact that the thermal shrinkage rate is less likely to vary depending on the mold temperature, etc., and high mechanical strength. Examples of the crystalline thermoplastic resin include polyamide resins and crystalline polyester resins, and polyamide resins are preferred. The polyamide resin is a polymer having an acid amide obtained by ring-opening polymerization of lactam, polycondensation of aminocarboxylic acid, or polycondensation of diamine and dibasic acid as a repeating unit. Specifically, polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 66, polyamide 610, polyamide 612, polyamide 1010, polyamide 1012, polyamide 6I, polyamide 6 / 66, polyamide 6T / 6I, polyamide 6 / 6T, polyamide 66 / 6T, polyamide 66 / 6T / 6I, polytrimethylhexamethylene terephthalamide, polybis(4-aminocyclohexyl)methane dodecamide, polybis(3-methyl-4-aminocyclohexyl)methane dodecamide, polyundecamethylene hexahydroterephthalamide, and xylylenediamine-based polyamide resins described below can be mentioned. Here, the above "I" represents an isophthalic acid component, and "T" represents a terephthalic acid component. As the polyamide resin used in this embodiment, an appropriate one is selected in consideration of various properties of these polyamide resins and the uses of the intended molded products.

[0013] Among the above polyamide resins, a polyamide resin (xylylenediamine-based polyamide resin) composed of a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, in which 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 4 to 20 carbon atoms is preferred.

[0014] In the xylylenediamine-based polyamide resin used in this embodiment, 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 paraxylylenediamine, more preferably containing 50 to 90 mol% of metaxylylenediamine and 10 to 50 mol% of paraxylylenediamine (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 paraxylylenediamine. 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 paraxylylenediamine.

[0015] 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, and 2,4,4-trimethylhexamethylenediamine; 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, and bis(aminomethyl)tricyclodecane; and diamines having an aromatic ring such as bis(4-aminophenyl)ether, paraphenylenediamine, and bis(aminomethyl)naphthalene. One kind or a mixture of two or more kinds can be used.

[0016] The xylylenediamine-based polyamide resin used in this embodiment has 70 mol% or more, preferably 75 mol% or more, more preferably 85 mol% or more, still more preferably 95 mol% or more, and even more preferably 99 mol% or more of the structural units derived from dicarboxylic acid derived from α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms.

[0017] Examples of the α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms include succinic acid, glutaric acid, adipic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, etc., and adipic acid and / or sebacic acid are preferred. The α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms can be used alone or in a mixture of two or more.

[0018] Examples of the dicarboxylic acid components other than the above α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms include 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 one or more of them can be used in a mixture.

[0019] As an embodiment of the xylylenediamine-based polyamide resin, the raw material xylylenediamine contains 50 to 90 mol% of metaxylylenediamine and 10 to 50 mol% of p-xylylenediamine, and it is preferable that the α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms contains adipic acid and / or sebacic acid. More preferably, 90 mol% or more of the raw material diamine is xylylenediamine, and the xylylenediamine contains 60 to 80 mol% of metaxylylenediamine and 40 to 20 mol% of p-xylylenediamine in a total of 99 mol% or more, and 90 mol% or more of the α,ω-linear aliphatic dicarboxylic acid is adipic acid and / or sebacic acid.

[0020] In addition, the xylylenediamine-based polyamide resin used in this embodiment is mainly composed of structural units derived from diamine and structural units derived from dicarboxylic acid, but it does not completely exclude structural units other than these. Needless to say, 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 structural units derived from diamine and structural units derived from dicarboxylic acid is the largest among all the structural units. In this embodiment, in the xylylenediamine-based polyamide resin, the total of the structural units derived from diamine and the structural units derived from dicarboxylic acid preferably accounts for 90% or more of all the structural units, and more preferably 95% or more.

[0021] The resin composition of this embodiment preferably contains a crystalline thermoplastic resin (preferably a polyamide resin, more preferably an xylylenediamine-based 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 crystalline thermoplastic resin is preferably 80% by mass or less, and more preferably 75% by mass or less. The resin composition of this embodiment may contain only one kind of crystalline thermoplastic resin, or may contain two or more kinds. When containing two or more kinds, the total amount is preferably within the above range.

[0022] <Reinforcing filler> The resin composition of this embodiment contains a reinforcing filler in a ratio of 10 to 120 parts by mass with respect to 100 parts by mass of the crystalline thermoplastic resin. By containing the reinforcing filler in the above ratio, 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. As the reinforcing filler in this embodiment, it has the effect of improving the mechanical properties of the resin composition obtained by blending it with the resin, and commonly used 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, potassium titanate fiber, etc. can preferably be used. Also, fillers such as particulate or amorphous fillers such as calcium carbonate, titanium oxide, feldspar minerals, clay, organic clay, glass beads, etc.; flaky reinforcing materials such as glass flakes, mica, graphite, etc. can also be used. Among them, from the viewpoints of mechanical strength, rigidity and heat resistance, it is preferable to use fibrous fillers, particularly glass fiber. As the glass fiber, either those with a round cross-sectional shape or those with an irregular cross-sectional shape can be used. It is more preferable to use the reinforcing filler which has been surface-treated with a surface treatment agent such as a coupling agent. Glass fiber with the surface treatment agent attached is preferable because it is excellent in durability, heat and humidity resistance, hydrolysis resistance, and heat shock resistance.

[0023] 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, etc., and in particular, E glass (alkali-free glass) is preferable. The glass fiber refers to those having a circular or polygonal cross-sectional shape when cut perpendicular to the length direction and presenting a fibrous appearance.

[0024] 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 a single fiber, a "glass roving" obtained by continuously winding a plurality of single fibers twisted together, a "chopped strand" cut to a length of 1 to 10 mm, a "milled fiber" pulverized to a length of 10 to 500 μm, and the like. 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 obtainable. Glass fibers with different forms can also be used in combination.

[0025] 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 warping of the obtained molded product can be more effectively suppressed. Also, in this embodiment, even when using glass fibers with a circular cross-section, the warping can be effectively suppressed.

[0026] 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 with respect to 100 parts by mass of the crystalline thermoplastic resin. Regarding the upper limit value, it is 120 parts by mass or less, more preferably 110 parts by mass or less with respect to 100 parts by mass of the crystalline thermoplastic 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 containing two or more kinds, 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.

[0027] <Light-transmitting dye having a perylene skeleton> The resin composition of the present embodiment contains a light-transmitting dye having a perylene skeleton in a proportion of 0.01 to 1.0 parts by mass with respect to 100 parts by mass of the crystalline thermoplastic resin. By blending a light-transmitting dye having a perylene skeleton, it becomes possible to effectively suppress color transfer to other members (particularly, an absorption resin member). The light-transmitting dye used in the present embodiment is a black dye, a black-purple dye, etc., and a dye that appears black to human vision is preferable. Further, the light-transmitting dye is blended so that at least one kind of crystalline thermoplastic resin (preferably a polyamide resin, more preferably a xylylenediamine-based polyamide resin), 30% by mass of glass fiber, and 0.2% by mass of a dye (a dye considered to be a light-transmitting dye) total 100% by mass, and when the light transmittance at a wavelength of 1070 nm is measured, the dye having a transmittance of 20% or more is included. The light-transmitting dye may be a dye or a pigment, but a pigment is preferable. Examples of the dye having a perylene skeleton include Spectrasence K0087 (former: Lumogen® Black K0087, Lumogen Black FK4280), Spectrasence K0088 (former: Lumogen Black K0088, Lumogen Black FK4281) manufactured by BASF Color & Effect Japan Co., Ltd.

[0028] The resin composition of the present embodiment contains 0.01 part by mass or more of a light-transmitting dye having a perylene skeleton with respect to 100 parts by mass of the crystalline thermoplastic resin, preferably 0.05 part by mass or more, more preferably 0.08 part by mass or more, still more preferably 0.10 part by mass or more, even more preferably 0.15 part by mass or more, further even more preferably 0.18 part by mass or more, and particularly even more preferably 0.20 part by mass or more. Further, the resin composition of the present embodiment contains 1.0 part by mass or less of a light-transmitting dye having a perylene skeleton with respect to 100 parts by mass of the crystalline thermoplastic resin, preferably 0.8 part by mass or less, more preferably 0.6 part by mass or less, even more preferably 0.5 part by mass or less, and further even more preferably 0.45 part by mass or less. 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.

[0029] <Copper compound> The resin composition of this embodiment may contain a copper compound. By using a copper compound, it becomes possible to achieve significantly excellent heat aging resistance. Examples of the copper compound used in this embodiment include copper halides (for example, copper iodide, copper bromide, copper chloride) and copper acetate, and are preferably selected from cuprous iodide, cupric iodide, cuprous bromide, cupric bromide, cuprous acetate, cupric acetate, cuprous chloride, and cupric chloride, more preferably selected from cuprous iodide, copper acetate, and cuprous chloride, and even more preferably cuprous iodide. Further, the copper compound is preferably used in combination with an alkali metal halide described later. When the copper compound and the alkali metal halide are combined, it is preferably a mixture of copper compound:alkali metal halide in a mass ratio of 1:1 to 1:15, more preferably a mixture of 1:1 to 1:5, and even more preferably a mixture of 1:2 to 1:4. Regarding the case of combining the copper compound and the alkali metal halide, the descriptions in paragraphs 0046 to 0048 of Japanese Patent Application Laid-Open No. 2013-513681 can also be referred to, and these contents are incorporated herein.

[0030] The proportion of the copper compound in the resin composition of this embodiment is preferably 0.01 to 1% by mass, more preferably 0.05% by mass or more, and more preferably 0.5% by mass or less. The resin composition of the present embodiment may contain only one kind or two or more kinds of copper compounds. When two or more kinds are contained, the total amount is preferably within the above range.

[0031] <Alkali metal halide> The resin composition of the present embodiment may contain an alkali metal halide. By using an alkali metal halide, the heat aging resistance and the heat and humidity resistance tend to be further improved. The alkali metal halide used in the present embodiment refers to a halide of an alkali metal. As the alkali metal, potassium and sodium are preferable, and potassium is more preferable. As the halogen atom, iodine, bromine, and chlorine are preferable, and iodine is more preferable. Specific examples of the alkali metal halide used in the present embodiment include potassium iodide, potassium bromide, potassium chloride, and sodium chloride, and potassium iodide is preferable.

[0032] The proportion of the alkali metal halide in the resin composition of the present embodiment is preferably 0.01 to 1% by mass, more preferably 0.1% by mass or more, and still more preferably 0.5% by mass or less. The resin composition of the present embodiment may contain only one kind or two or more kinds of alkali metal halides. When two or more kinds are contained, the total amount is preferably within the above range.

[0033] <Cerium oxide> The resin composition of the present embodiment preferably contains cerium oxide. By containing cerium oxide, color transfer to other members (particularly, an absorption resin member that is a partner for laser welding) can be effectively suppressed even after being placed under high-temperature and high-humidity conditions. Furthermore, since cerium oxide has a relatively low Mohs hardness, it is possible to hardly damage reinforcing fillers such as glass fibers. The cerium oxide in this embodiment refers to cerium oxide with a purity of 90% by mass or more. That is, the cerium oxide may contain impurities. The cerium oxide used in this embodiment is preferably cerium oxide with a lanthanum content measured by ICP emission spectrometry of more than 0% by mass and 1% by mass or less, more preferably cerium oxide with a lanthanum content measured by ICP emission spectrometry of 0.01 - 0.7% by mass, still more preferably cerium oxide with a lanthanum content measured by ICP emission spectrometry of 0.02 - 0.4% by mass, and even more preferably cerium oxide with a lanthanum content measured by ICP emission spectrometry of 0.05 - 0.2% by mass. By setting the range in this way, color transfer to other members can be suppressed more effectively. In this way, by using cerium oxide containing lanthanum in a trace proportion, a desired amount of lanthanum can be easily blended into the resin composition.

[0034] In this embodiment, the cerium content in the cerium oxide is preferably 73% by mass or more, more preferably 75% by mass or more, and still more preferably 77% by mass or more. Also, the upper limit of the cerium oxide content is preferably 85% by mass or less, more preferably 83% by mass or less, and still more preferably 80% by mass or less.

[0035] The median diameter (particle size by laser diffraction scattering method) of the cerium oxide used in this embodiment is preferably 3 μm or less. The lower limit of the median diameter is, for example, 0.1 μm or more. By using cerium oxide having the above median diameter, damage to the reinforcing filler can be effectively suppressed, and a resin composition with more excellent mechanical strength can be obtained.

[0036] In the resin composition of this embodiment, the content of cerium oxide is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, in the resin composition. Further, as the upper limit value of the content of cerium oxide in the resin composition, it is preferably 5% by mass or less, more preferably 4% by mass or less, still more preferably 3% by mass or less, and even more preferably 2% by mass or less.

[0037] <Release agent> The resin composition of this 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 this embodiment contains a release agent, its content is preferably 0.05 to 3% by mass, more preferably 0.1 to 0.8% by mass, still more preferably 0.2 to 0.6% by mass, in the resin composition. The resin composition of this embodiment may contain only one kind of release agent or two or more kinds of release agents. When two or more kinds are contained, it is preferable that the total amount is within the above range.

[0038] <Nucleating agent> The resin composition of this embodiment may contain a nucleating agent. By blending a nucleating agent, crystallization is promoted and solidification becomes easier, so that the molding cycle can be improved. The nucleating agent is not particularly limited as long as it is unmelted during melt processing and can become nuclei of crystals during the cooling process. Among them, talc and calcium carbonate are preferred, and talc is more preferred. 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, still more preferably 28 μm or less, even more preferably 15 μm or less, and yet even more preferably 10 μm or less.

[0039] The proportion of the nucleating agent in the resin composition of the present 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 the present embodiment may contain only one type of nucleating agent or two or more types. When two or more types are contained, the total amount preferably falls within the above range.

[0040] <Other components> The resin composition of the present embodiment may contain other components as long as the gist of the present embodiment is not deviated from. Examples of 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, and the like. These components may be used alone or in combination of two or more. In addition, for the resin composition of the present embodiment, the content of each component is adjusted so that the total of the components becomes 100% by mass. The resin composition contains a crystalline thermoplastic resin, a reinforcing filler, a light-transmissive dye having a perylene skeleton, at least one of a copper compound, an alkali metal halide, and cerium oxide, and further, the content of other additives and the like. In the present embodiment, an aspect is exemplified in which the total of the crystalline thermoplastic resin, the reinforcing filler, the light-transmissive dye having a perylene skeleton, at least one of the copper compound, the alkali metal halide, and cerium oxide, the nucleating agent, and the release agent occupies 99% by mass or more of the resin composition.

[0041] <Content of lanthanum in the resin composition> The resin composition of this embodiment preferably has a lanthanum content of more than 0 mass ppm and 150 mass ppm or less. By containing a trace amount of lanthanum in this way, color transfer can be more effectively suppressed even after being placed under high temperature and high humidity. Also, by setting it to 150 mass ppm or less, particularly 40 mass ppm or less, the tensile strength after being placed under high temperature and high humidity can be maintained at a high level. The lower limit of the lanthanum content in the resin composition is preferably 0.01 mass ppm or more, more preferably 0.05 mass ppm or more, still more preferably 0.1 mass ppm or more, even more preferably 0.5 mass ppm or more, even more preferably 0.8 mass ppm or more, still more preferably 1 mass ppm or more, and particularly even more preferably 2 mass ppm or more. Also, the upper limit of the lanthanum content in the resin composition is preferably 40 mass ppm or less, more preferably 30 mass ppm or less, still more preferably 25 mass ppm or less, even more preferably 20 mass ppm or less, even more preferably 15 mass ppm or less, still more preferably 12 mass ppm or less, particularly even more preferably 8 mass ppm or less, and even more particularly preferably 5 mass ppm or less.

[0042] In the resin composition of this embodiment, usually, lanthanum is incorporated by the lanthanum contained in cerium oxide.

[0043] <Manufacturing method of resin composition> The method for producing 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 degassing from a vent port as a kneader is preferred. The above crystalline thermoplastic resin, reinforcing filler, light-transmissive dye, copper iodide, potassium iodide, and at least one of cerium oxide, and other additives optionally blended may be supplied to the kneader all at once, or after supplying the crystalline thermoplastic resin, 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 the respective components may be premixed and kneaded in advance. In the present embodiment, the light-transmissive dye may be prepared in advance as a masterbatch with a crystalline thermoplastic resin or the like, and then kneaded with other components (at least one of a crystalline thermoplastic resin, a reinforcing filler, a light-transmissive dye, copper iodide, potassium iodide, and cerium oxide, etc.) to obtain the resin composition in the present embodiment.

[0044] The method for producing a 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, etc. 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 cylinder temperature to 250 to 300°C.

[0045] <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, particularly a kit for producing a molded article (laser-welded body) by laser welding. That is, the resin composition of the present embodiment contained in the kit serves as a light-transmissive resin composition, and a molded article formed from such a light-transmissive resin composition becomes a transmissive resin member for laser light during laser welding. On the other hand, a molded article formed from the light-absorbing resin composition becomes an absorbing resin member for laser light during laser welding.

[0046] <<Light-absorbing resin composition>> The light-absorbing resin composition used in this 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-transmitting resin composition (the resin composition of this embodiment), in particular, a crystalline thermoplastic resin is preferable, a polyamide resin and a crystalline polyester resin are more preferable, and a polyamide resin is even more preferable. Also, the thermoplastic resin may be one kind or two or more kinds. As for the polyamide resin used in the light-absorbing resin composition, although its type or the like is not defined, the above-mentioned crystalline thermoplastic resin is preferable. Examples of the reinforcing filler include fillers capable of absorbing laser light such as glass fiber, carbon fiber, silica, alumina, carbon black, and inorganic powder coated with a material that absorbs laser, and glass fiber is preferable. Glass fiber is synonymous with the glass fiber that may be blended in the resin composition of the above-mentioned embodiment. The content of the reinforcing filler is preferably 20 to 70% by mass, more preferably 25 to 60% by mass, and even 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 this embodiment, in the range of 900 nm to 1100 nm, are included. Also, in the light-absorbing dye, for example, when 0.3 part by mass is blended with respect to 100 parts by mass of the crystalline thermoplastic resin and the light transmittance is measured by the measurement method described in the examples below, dyes having a transmittance of less than 30%, and further 10% or less, are included. Specific examples of the light-absorbing pigment include inorganic pigments (black pigments such as carbon black (e.g., 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 even more preferred. These light-absorbing pigments may be used in combination of two or more. The content of the light-absorbing pigment is preferably 0.01 to 30 parts by mass with respect to 100 parts by mass of the crystalline thermoplastic resin.

[0047] Regarding the components excluding the light-transmitting pigment and the reinforcing filler in the resin composition and the components excluding the light-absorbing pigment 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 even more preferably 95 to 100% by mass is common.

[0048] <<Laser Welding Method>> Next, the laser welding method will be described. In this embodiment, a molded article (transparent resin member) formed from the resin composition of this embodiment and a molded article (absorbing resin member) formed from the above light-absorbing resin composition can be laser welded to manufacture 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 member is not particularly limited. However, since the members are joined by laser welding and used, they usually have a shape with at least surface contact portions (plane, curved surface). In laser welding, the laser light transmitted through the transmissive resin member is absorbed by the absorptive resin member, causing the absorptive resin member to melt and the two members to be welded together. In particular, the absorptive resin member melts and transfers heat to the transmissive member, and the two members are welded together. The molded product formed from the resin composition of the present embodiment has high transparency to laser light, so it can be preferably used as the transmissive resin member. Here, the thickness of the member through which the laser light passes (the thickness in the laser transmission direction at 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.

[0049] The laser light source used for laser welding can be determined according to the light absorption wavelength of the light-absorbing dye. Lasers in the wavelength range of 900 to 1100 nm are preferred. For example, semiconductor lasers or fiber lasers can be used.

[0050] More specifically, for example, when welding the transmissive resin member and the absorptive 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 it may be a combination of flat surfaces, curved surfaces, or a flat surface and a curved surface. Next, laser light is irradiated from the side of the transmissive resin member. At this time, a lens may be used to focus the laser light at the interface between the two if necessary. The focused beam passes through the transmissive resin member, is absorbed near the surface of the absorptive resin member, generates heat, and melts. Next, the heat is also transferred to the transmissive 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 in which the transmissive resin member and the absorptive resin member are welded 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 members that form a part of these.

[0051] The molded article 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 electrical 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 this embodiment are suitable for in-vehicle cameras.

Examples

[0052] 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, etc. used in the examples are difficult to obtain due to being obsolete, etc., measurement can be performed using other equipment having equivalent performance.

[0053] <Polyamide resin> MP10: The molar ratio of metaxylylenediamine / paraxylylenediamine (M / P) = 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. Then, while stirring the contents, a mixed diamine of para-xylylenediamine (manufactured by Mitsubishi Gas Chemical Company) and meta-xylylenediamine (manufactured by Mitsubishi Gas Chemical Company) with a molar ratio of 3:7 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 approximately 1:1. After completion of the dropping, the reaction was continued for 60 minutes to adjust the amount of components with a molecular weight of 1,000 or less. After completion of the reaction, the contents were taken out in a strand shape and pelletized with a pelletizer to obtain a polyamide resin (MP10).

[0054] MP6: M / P molar ratio = 7:3, synthesized according to the following synthesis example. <<Synthesis Example of MP6 (M / P Molar Ratio = 7:3)>> Adipic acid (manufactured by Rhodia) was heated and dissolved in a reaction vessel under a nitrogen atmosphere. Then, while stirring the contents, a mixed diamine of para-xylylenediamine (manufactured by Mitsubishi Gas Chemical Company) and meta-xylylenediamine (manufactured by Mitsubishi Gas Chemical Company) with a molar ratio of 3:7 was gradually dropped under pressure (0.35 MPa) while raising the temperature to 270 °C so that the molar ratio of diamine to adipic acid became approximately 1:1. After completion of the dropping, the pressure was reduced to 0.06 MPa and the reaction was continued for 10 minutes to adjust the amount of components with a molecular weight of 1,000 or less. Then, the contents were taken out in a strand shape and pelletized with a pelletizer to obtain a polyamide resin (MP6).

[0055] PA66: Polyamide 66, manufactured by INVISTA Nylon Polymer, Invista U4800

[0056] <Talc #5000S: Manufactured by Hayashi Kasei Co., Ltd., Micron White <Copper(I) Iodide (CuI)> Manufactured by Nippon Chemical Industry Co., Ltd., Cuprous Iodide <Potassium Iodide> Manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. <Zinc(II) Stearate> Manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.

[0057] <Release Agent> CS8CP: Manufactured by Nitto Kasei Kogyo Co., Ltd., montanic acid soap

[0058] <Cerium oxide Cerium oxide 1: Cerium oxide with a purity of 90% by mass or more, manufactured by Tribach Industry Japan Co., Ltd., Cerium Oxide Hydrate 90, cerium content 72.1% by mass, lanthanum content 4.4% by mass, median diameter (particle size by laser diffraction scattering method) 2 μm or less Cerium oxide 2: Cerium oxide with a purity of 90% by mass or more, manufactured by Tribach Industry Japan Co., Ltd., Cerium Hydrate 90, cerium content 78.5% by mass, lanthanum content 0.1% by mass, median diameter (particle size by laser diffraction scattering method) 3 μm or less

[0059] <Analysis of lanthanum and cerium contents in cerium oxide The sample was heated and dried at 120 °C for 2 hours in the air. 100 mg of the sample was precisely weighed, perchloric acid, hydrogen peroxide solution and water were added, and after thermal decomposition, water was added to make a constant volume. This solution was diluted, and Ce was quantified by the acid concentration matching calibration curve method and La was quantified by the standard addition calibration curve method using ICP emission spectrometry (ICP-AES).

[0060] <Light-transmitting dye Lumogen 4281 (K0088): Manufactured by BASF Color & Effect Japan Co., Ltd., perylene pigment, Lumogen (registered trademark) Black K 0088 (former Lumogen Black FK 4281) LTW-8701H: Manufactured by Orient Chemical Co., Ltd., SolventRed179 0.46% by mass, SolventYeloLw163 0.23% by mass, AcidBlue80 6.53% by mass LTW-8731H: Manufactured by Orient Chemical Co., Ltd., SoventRed179 1.56% by mass, AcidBlue80 4.48% by mass

[0061] <Reinforcing filler ECS03T-211H: Glass fiber of E-glass, manufactured by Nippon Electric Glass Co., Ltd., weight average fiber diameter 10.5 μm, cut length 3.5 mm

[0062] Example 1 <Compound> The components other than the reinforcing filler were weighed and dry-blended so as to have the compositions shown in Table 1 below (each component in Table 1 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., TEM26SS) using a twin-screw type cassette weighing feeder (manufactured by Kubota Corporation, CE-W-1-MP). For the reinforcing filler, 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 and the like to obtain resin composition pellets. The temperature setting of the extruder was 280°C. The pellets obtained above were dried at 120°C for 4 hours, and then No. 4 specimens (1.5 mm thick) based on ASTM D638 standard were produced using an injection molding machine (manufactured by Japan Steel Works, Ltd., 50T clamping force injection molding machine J-50ADS).

[0063] <Color transfer test after being placed under high temperature and high humidity> In Example 1, except for the light-transmitting pigment, the other components were blended, extruded, and injection-molded in the same manner to produce No. 4 specimens (1.5 mm thick) (counterpart members) based on ASTM D638 standard. The No. 4 specimen based on ASTM D638 standard obtained from the resin pellets described in Example 1 and the above-mentioned counterpart member were overlapped and clipped. Then, they were left standing at 85°C under the condition of 85% relative humidity for 50 hours and 1000 hours. After standing, the presence or absence of color transfer of the light-transmitting pigment to the counterpart member was visually confirmed and evaluated by classifying it into 5 grades from A to E. Those with no color transfer were rated as A, and those with the most severe color transfer were rated as E. In making the judgment, the degree of color transfer of the test piece after leaving the laser welded body of Comparative Example 2 standing at 85°C under the condition of 85% relative humidity for 1000 hours was rated as D, and the judgment was made based on this. The evaluation was carried out by 10 experts and was by majority vote.

[0064] Examples 2 to 36, Comparative Examples 1 to 18 In Example 1, the compounding amounts of the raw materials were changed as shown in Tables 1 to 6 (the amounts of the respective components in Tables 2 to 6 are expressed in parts by mass), and resin composition pellets and No. 4 specimens (1.5 mm thick) based on ASTM D638 standard were obtained. At this time, the temperature setting of the extruder was 280°C when MP6 was used as the polyamide resin and 280°C when PA66 was used as the polyamide resin. A color shift test was conducted in the same manner as in Example 1 after placing it under high temperature and high humidity. In Example 2, as the mating member, the one prepared in the same manner as the resin composition described in Example 2 of the table, except for the light-transmitting dye, was used. In Example 3, as the mating member, the one prepared in the same manner as the resin composition described in Example 3 of the table, except for the light-transmitting dye, was used. The same applies to Examples 4 to 36 and Comparative Examples 1 to 18.

[0065] [Table 1]

[0066] [Table 2]

[0067] [Table 3]

[0068] [Table 4]

[0069] [Table 5]

[0070] [Table 6]

[0071] In the above, the amount of lanthanum in the resin composition was calculated from the amount of lanthanum derived from cerium oxide. The amount of lanthanum in other components was below the detection limit. As is clear from the above results, the resin composition of the present invention effectively suppressed color transfer. On the other hand, when a dye other than the light-transmitting dye having a perylene skeleton was used, the degree of color transfer was high.

Claims

1. Based on 100 parts by mass of the crystalline thermoplastic resin, 10 to 120 parts by mass of a reinforcing filler, 0.01 to 1.0 part by mass of a light-transmitting dye having a perylene skeleton, and at least one of a copper compound, an alkali metal halide, and cerium oxide, wherein the light-transmitting dye having a perylene skeleton is a black dye, A light-transmitting resin composition for laser welding.

2. A light-transmitting resin composition for laser welding, based on 100 parts by mass of the crystalline thermoplastic resin, containing 10 to 120 parts by mass of a reinforcing filler, 0.01 to 1.0 part by mass of a light-transmitting dye having a perylene skeleton, and at least one of a copper compound, an alkali metal halide, and cerium oxide, wherein the content of lanthanum in the resin composition is more than 0 ppm by mass and 40 ppm by mass or less, the resin composition.

3. A light-transmitting resin composition for laser welding, based on 100 parts by mass of the crystalline thermoplastic resin, containing 10 to 120 parts by mass of a reinforcing filler, 0.01 to 1.0 part by mass of a light-transmitting dye having a perylene skeleton, and at least one of a copper compound, an alkali metal halide, and cerium oxide, wherein the resin composition contains cerium oxide having a lanthanum content of more than 0% by mass and 1% by mass or less as measured by ICP emission spectrometry, the resin composition.

4. A light-transmitting resin composition for laser welding, based on 100 parts by mass of the crystalline thermoplastic resin, containing 10 to 120 parts by mass of a reinforcing filler, 0.01 to 1.0 part by mass of a light-transmitting dye having a perylene skeleton, and at least one of a copper compound, an alkali metal halide, and cerium oxide, wherein the content of the cerium oxide is 0.01 to 5% by mass in the resin composition, the resin composition.

5. The resin composition according to any one of Claims 1 to 4, wherein the crystalline thermoplastic resin contains a polyamide resin.

6. The resin composition according to Claim 5, wherein 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 4 to 20 carbon atoms.

7. The resin composition according to any one of Claims 1 to 6, wherein the light-transmitting dye having a perylene skeleton is a pigment.

8. 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.

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

10. The molded article according to claim 9, which is an in-vehicle camera component.

11. An in-vehicle camera comprising the molded article according to claim 10.

12. 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.

Images