JP7492517B2 - Resin composition, molded article, kit, and method for manufacturing molded article - Google Patents

Description

The present invention relates to a resin composition, a molded article, a kit, and a method for manufacturing a molded article. In particular, the present invention relates to a resin composition suitable for laser welding, as well as a kit, a method for manufacturing a molded article, and a molded article using the resin composition. The resin composition of the present invention is primarily used as a resin composition that transmits light for laser welding (light-transmitting resin composition).

Polyamide resin, a typical engineering plastic, is easy to process and 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 begun to be manufactured from polyamide resin. For example, various welding techniques such as adhesive welding, vibration welding, ultrasonic welding, hot plate welding, injection welding, and laser welding are used to bond parts with hollow parts such as intake manifolds.

However, welding with adhesives has problems such as the time lost until the material hardens, as well as environmental impacts such as pollution of the surrounding area. Problems have been pointed out with ultrasonic welding and hot plate welding, such as damage to the product due to vibration and heat, and the need for post-processing due to the generation of wear powder and burrs. Injection welding also often requires special molds and molding machines, and furthermore cannot be used unless the material has good fluidity.

Laser welding, on the other hand, is a method of joining a resin member that is transparent (also called non-absorbent or weakly absorbent) to laser light (hereinafter sometimes referred to as the "transmissive resin member") to a resin member that is absorbent to laser light (hereinafter sometimes referred to as the "absorbent resin member") by contacting and welding the two resin members. Specifically, this method irradiates the joining surface from the transmissive resin member side with laser light, and melts and joins the absorbing resin member that forms the joining surface with the energy of the laser light. Laser welding does not produce abrasion powder or burrs, and causes little damage to the product. Furthermore, polyamide resin itself is a material with a relatively high laser transmittance, so processing polyamide resin products using laser welding technology has recently been attracting attention.

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

JP 2008-308526 A

Here, the resin composition for laser welding may also be required to have Charpy impact strength, and may also be required to have flame retardancy.
However, as a result of investigations conducted by the present inventors, it has been found that it is difficult to achieve both excellent flame retardancy and high Charpy impact strength.
In particular, there is a demand for a resin composition having an unnotched Charpy impact strength of 50 kJ/ ^m2 or more according to ISO 179 when molded to a thickness of 4 mm, but it has been found to be difficult to provide a molded product that achieves this value while also having excellent flame retardancy.
The present invention aims to solve such problems, and to provide a resin composition that can be used for laser welding, which achieves high light transmittance and high flame retardancy, and is capable of providing a molded article with high Charpy impact strength, as well as a molded article, a kit, and a method for manufacturing a molded article.

As a result of intensive research conducted by the present inventors in light of the above problems, the above problems have been solved by the following means.
<1> A resin composition comprising a polyamide resin, a flame retardant, an elastomer, and a light-transmitting dye, wherein the resin composition has a light transmittance of 30% or more at a wavelength of 940 nm when molded to a thickness of 1 mm, and has an unnotched Charpy impact strength of 50 kJ/m2 or ^more and a notched Charpy impact strength of 10 kJ/m2 or ^more according to ISO 179 when molded to a thickness of 4 mm, and satisfies V-0 in a UL94 flammability test when molded to a thickness of 0.75 mm.
<2> The resin composition according to <1>, comprising a xylylenediamine-based polyamide resin, the polyamide resin being composed of diamine-derived structural units and dicarboxylic acid-derived structural units, in which 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine, and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.
<3> The resin composition according to <2>, wherein the xylylenediamine includes metaxylylenediamine and paraxylylenediamine, and the α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms includes adipic acid.
<4> The resin composition according to any one of <1> to <3>, wherein the elastomer comprises a styrene block polymer.
<5> The resin composition according to <4>, wherein the amount of polystyrene in the styrene block polymer is 0.3 to 1.0 mass% in the resin composition.
<6> The resin composition according to any one of <1> to <5>, further comprising a polyphenylene ether resin.
<7> The resin composition according to any one of <1> to <6>, comprising a styrene block polymer and a polyphenylene ether-based resin, wherein the mass ratio of the styrene block polymer to the polyphenylene ether-based resin is 1:1 to 1:35.
<8> The resin composition according to any one of <1> to <7>, further comprising a flame retardant auxiliary.
<9> The resin composition according to <8>, comprising zinc oxide as the flame retardant auxiliary.
<10> The resin composition according to <8> or <9>, wherein the content of the flame retardant auxiliary is 1.1 to 6.0 mass% of the resin composition.
<11> The resin composition according to any one of <1> to <10>, wherein the content of the polyamide resin other than the xylylenediamine-based polyamide resin in the resin composition is 4 mass% or less of the resin composition.
<12> The resin composition according to any one of <1> to <11>, wherein the flame retardant includes a phosphazene-based flame retardant.
<13> A resin composition comprising a xylylenediamine-based polyamide resin composed of diamine-derived structural units and dicarboxylic acid-derived structural units, in which 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms; a phosphazene-based flame retardant; a styrene block polymer; a polyphenylene ether-based resin; and zinc oxide, wherein the content of polystyrene in the styrene block polymer is 0.3 to 1.0 mass % of the resin composition, the xylylenediamine includes meta-xylylenediamine and para-xylylenediamine, the α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms includes adipic acid, the content of the flame retardant auxiliary is 1.1 to 6.0 mass % of the resin composition, and the content of polyamide resins other than the xylylenediamine-based polyamide resin in the resin composition is 4 mass % or less of the resin composition.
<14> A molded article formed from the polyamide resin composition according to any one of <1> to <13>.
<15> A kit comprising the resin composition according to any one of <1> to <13> and a light-absorbing resin composition containing a thermoplastic resin and a light-absorbing dye.
<16> A method for producing a molded article, comprising laser welding a molded article obtained by molding the resin composition according to any one of <1> to <13> and a molded article obtained by molding a light-absorbing resin composition containing a thermoplastic resin and a light-absorbing dye.
<17> A molded product obtained by molding the resin composition according to any one of <1> to <13> or the kit according to <15>.

The present invention makes it possible to provide a resin composition that can be used for laser welding, which achieves high light transmittance and high flame retardancy, and is capable of producing molded products with high Charpy impact strength, as well as a molded product, a kit, and a method for producing a molded product.

The present invention will be described in detail below. In this specification, the word "-" is used to mean that the numerical values before and after it are included as a lower limit and an upper limit.
In this specification, various physical properties and characteristic values are those at 23° C. unless otherwise specified.

The resin composition of the present invention is a resin composition containing a polyamide resin, a flame retardant, an elastomer, and a light-transmitting dye, and when the resin composition is molded to a thickness of 1 mm, the light transmittance at a wavelength of 940 nm is 30% or more, when the resin composition is molded to a thickness of 4 mm, the unnotched Charpy impact strength according to ISO179 is 50 kJ/m ² or more, and the notched Charpy impact strength according to ISO179 is 10 kJ/m ² or more, and when the resin composition is molded to a thickness of 0.75 mm, it conforms to V-0 in the UL94 flammability test. By adopting such a configuration, it is possible to provide a molded product that is usable for laser welding and has high light transmittance and flame retardancy while maintaining high Charpy impact strength.
The Charpy impact strength and flame retardancy are generally adjusted as follows. In order to impart flame retardancy, it is necessary to add a flame retardant and further a flame retardant auxiliary, but if the content of these components is high, the Charpy impact strength tends to be low. In addition, if an elastomer is added, the Charpy impact strength tends to be high, but if the content of the elastomer is high, the light transmittance is low. In addition, by using a polyamide resin (xylylenediamine-based polyamide resin) that is composed of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, in which 70 mol % or more of the diamine-derived structural unit is derived from xylylenediamine, and 70 mol % or more of the dicarboxylic acid-derived structural unit is derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, the Charpy impact strength tends to be higher. Conversely, if the content of other resin components is high, the Charpy impact strength may be low. In the present invention, by adjusting the components and contents that constitute the resin composition, a resin composition that achieves high light transmittance and high flame retardancy and can provide a molded product with high Charpy impact strength has been successfully provided.

<Polyamide resin>
The resin composition of the present invention contains a polyamide resin. Any known polyamide resin can be used as the polyamide resin, and the resin composition preferably contains a semi-aromatic polyamide resin and/or an aliphatic polyamide resin, and more preferably contains a semi-aromatic polyamide resin.
The semi-aromatic polyamide resin is composed of diamine-derived structural units and dicarboxylic acid-derived structural units, and 20 to 80 mol % of the total of the diamine-derived structural units and the dicarboxylic acid-derived structural units are structural units containing aromatic rings. By using such a semi-aromatic polyamide resin, the mechanical strength of the obtained molded product can be increased.
Examples of semi-aromatic polyamide resins include terephthalic acid-based polyamide resins (polyamide 6T, polyamide 9T, polyamide 10T) and xylylenediamine-based polyamide resins, with xylylenediamine-based polyamide resins being preferred.
The aliphatic polyamide resin is a polymer having structural units linked by amide bonds, such as acid amides obtained by ring-opening polymerization of lactams, polycondensation of aminocarboxylic acids, or polycondensation of diamines and dibasic acids, in which more than 80 mol % (preferably 90 mol % or more) of the raw material monomers are non-aromatic compounds.
Examples of the aliphatic polyamide resin include polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 66, polyamide 610, polyamide 612, polyamide 6/66, and polyamide 1010, with polyamide 66 being preferred.

As described above, the polyamide resin used in the present invention preferably contains a xylylenediamine-based polyamide resin. By containing a xylylenediamine-based polyamide resin, the Charpy impact strength tends to be high.
The xylylenediamine-based polyamide resin used in the present invention is composed of diamine-derived structural units and dicarboxylic acid-derived structural units, in which 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine, and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.
The diamine-derived constituent units of the xylylenediamine-based polyamide resin are more preferably 80 mol % or more, even more preferably 85 mol % or more, still more preferably 90 mol % or more, and even more preferably 95 mol % or more, of xylylenediamine-derived units.
The xylylenediamine preferably contains at least one of metaxylylenediamine and paraxylylenediamine, preferably contains 10 to 100 mol % metaxylylenediamine and 90 to 0 mol % paraxylylenediamine (however, the total of metaxylylenediamine and paraxylylenediamine does not exceed 100 mol %, the same applies below), more preferably contains 20 to 80 mol % metaxylylenediamine and 80 to 20 mol % paraxylylenediamine, and even more preferably contains 60 to 80 mol % metaxylylenediamine and 40 to 20 mol % paraxylylenediamine.
The dicarboxylic acid-derived constituent units of the xylylenediamine-based polyamide resin are preferably 80 mol % or more, more preferably 85 mol % or more, even more preferably 90 mol % or more, and even more preferably 95 mol % or more, derived from an α,ω-straight-chain aliphatic dicarboxylic acid having a carbon number of 4 to 20. Suitable α,ω-straight-chain aliphatic dicarboxylic acids having a carbon number of 4 to 20 include adipic acid, sebacic acid, suberic acid, dodecanedioic acid, and eicodionic acid, with adipic acid and sebacic acid being more preferred, and adipic acid being even more preferred.

Diamines other than xylylenediamine that can be used as the raw diamine component of xylylenediamine-based polyamide resins 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, 1,3-bis(aminomethyl)silane, and Examples of such diamines include alicyclic diamines such as 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. These can be used alone or in combination of two or more.

Examples of dicarboxylic acid components other than the above-mentioned α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms include phthalic acid compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and isomers of naphthalene dicarboxylic acids such as 1,2-naphthalene dicarboxylic acid, 1,3-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 1,6-naphthalene dicarboxylic acid, 1,7-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and 2,7-naphthalene dicarboxylic acid, and these can be used alone or in combination of two or more kinds.

The xylylenediamine-based polyamide resin used in the present invention is mainly composed of diamine-derived structural units and dicarboxylic acid-derived structural units, but does not completely exclude other structural units, and may, of course, 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 diamine-derived structural units and dicarboxylic acid-derived structural units is the largest among all structural units. In the present invention, the total of diamine-derived structural units and dicarboxylic acid-derived structural units in the xylylenediamine-based polyamide resin preferably accounts for 90% by mass or more of the total structural units, and more preferably accounts for 95% by mass or more.

The resin composition of the present invention preferably contains a polyamide resin (preferably a xylylenediamine-based polyamide resin) in a proportion of 20 to 70% by mass of the resin composition. The polyamide resin (preferably a xylylenediamine-based polyamide resin) is more preferably contained in a proportion of 22% by mass or more of the resin composition, and even more preferably contained in a proportion of 25% by mass or more. It is more preferably contained in a proportion of 65% by mass or less, even more preferably contained in a proportion of 60% by mass or less, even more preferably contained in a proportion of 50% by mass or less, even more preferably contained in a proportion of 40% by mass or less, even more preferably contained in a proportion of 35% by mass or less, and may be contained in a proportion of 32% by mass or less, or 30% by mass or less.
The xylylenediamine-based polyamide resin may contain only one type, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is in the above range.

<Other resins>
The resin composition of the present invention may or may not contain resin components other than the above-mentioned polyamide resin, the elastomer described below, and the polyphenylene ether resin.
Examples of other resins include olefin resins other than elastomers, vinyl resins, styrene resins, acrylic resins, polyester resins, polycarbonate resins, polyacetal resins, and the like.
Furthermore, the resin composition of the present invention is preferably configured to be substantially free of other resin components than the polyamide resin (preferably the xylylenediamine-based polyamide resin), the elastomer, and the polyphenylene ether-based resin. Substantially free means that the content of other resin components is 4% by mass or less of the resin composition, preferably 1% by mass or less, more preferably 0.5% by mass or less, and may even be 0.1% by mass or less, or even 0% by mass.

<Flame retardants>
The resin composition of the present invention contains a flame retardant.
As the flame retardant, various flame retardants such as halogen-based flame retardants and phosphorus-based flame retardants can be used, but phosphorus-based flame retardants are preferred, and phosphazene-based flame retardants are more preferred. By blending a phosphazene-based flame retardant, the flame retardancy of the resin composition tends to be higher.
For the flame retardant, the description in paragraphs 0049 to 0059 of JP2012-001580A can be referred to, the contents of which are incorporated herein by reference.

The content of the flame retardant (preferably a phosphazene-based flame retardant) in the resin composition of the present invention is preferably 1% by mass or more, more preferably 2% by mass or more, and more preferably 3% by mass or more of the resin composition. The upper limit is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably 8% by mass or less, even more preferably 6% by mass or less, and even more preferably 5% by mass or less. By setting the content in such a range, the laser weldability can be improved even if the total energy input during laser welding is reduced.
The resin composition of the present invention may contain only one type of flame retardant, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

The resin composition of the present invention is preferably substantially free of flame retardants other than the phosphazene-based flame retardant. "Substantially free" means that the content of flame retardants other than the phosphazene-based flame retardant is 10% by mass or less of the blended amount of the phosphazene-based flame retardant, preferably 5% by mass or less, and more preferably 1% by mass or less.

<Flame retardant synergist>
The resin composition of the present invention may contain a flame retardant auxiliary.
The flame retardant aid is preferably an oxide containing a metal selected from the group consisting of zinc, antimony, copper, magnesium, molybdenum, zirconium, tin, iron, titanium and aluminum.
The flame retardant auxiliary is preferably zinc oxide. By blending zinc oxide, the flame retardancy of the resin composition is increased, and the transmittance of the resin is not decreased regardless of the amount of zinc oxide added and the phosphorus atom concentration of the polyamide resin. The zinc oxide is preferably zinc borate. Zinc borate can be obtained from zinc oxide and boric acid _, and examples of the zinc borate include hydrates and anhydrides such as ZnO.B ₂ O 3.2H ₂ O and 2ZnO.3B ₂ O _{3.3.5H 2} O.

The content of the flame retardant assistant in the resin composition of the present invention is preferably 1.1 mass% or more of the resin composition, more preferably 1.5 mass% or more, and even more preferably 2.0 mass% or more. By making the amount of the flame retardant assistant 1.1 mass% or more, the flame retardancy can be more effectively exhibited. In addition, the upper limit of the amount of the flame retardant assistant is preferably 6.0 mass% or less, more preferably 5.5 mass% or less, and even more preferably 3.0 mass% or less. By making it 6.0 mass% or less, the Charpy impact strength, in particular the unnotched Charpy impact strength, can be effectively improved.
The resin composition of the present invention may contain only one type of flame retardant auxiliary, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

<Elastomer>
The resin composition of the present invention contains an elastomer. By containing the elastomer, it is possible to improve the impact resistance. As the elastomer, the elastomer described in paragraph 0033 of JP-A-2017-210591, the elastomer described in paragraphs 0075 to 0088 of JP-A-2012-251061, the elastomer described in paragraphs 0101 to 0107 of JP-A-2012-177047, and the like can be used, the contents of which are incorporated herein by reference.
The elastomer used in the present invention is preferably a block polymer. The block polymer is preferably a styrene block polymer. By blending a styrene block polymer, the transmittance can be further increased.

Examples of styrene block polymers include polystyrene-poly(ethylene/butylene)-polystyrene block polymer (SEBS), polystyrene-poly(ethylene/propylene)-polystyrene block polymer (SEPS), polystyrene-poly(ethylene/butylene) block polymer (SEB), polystyrene-poly(ethylene/propylene) block polymer (SEP), polystyrene-poly(ethylene/butylene)-polyolefin crystalline block polymer (SEBC), etc.

The styrene block polymer may have a cyclic acid anhydride group in the side chain. Examples of the cyclic acid anhydride group include maleic anhydride, succinic anhydride, phthalic anhydride, and glutaric anhydride groups, and maleic anhydride groups are preferred. Examples of commercially available thermoplastic elastomers having a cyclic acid anhydride group in the side chain include Tuftec (maleic anhydride-modified SEBS, M1913 (manufactured by Asahi Kasei Chemicals)), Tuftec (maleic anhydride-modified SEBS, M1943 (manufactured by Asahi Kasei Chemicals)), Kraton (maleic anhydride-modified SEBS, FG1901X (manufactured by Kraton Polymers)), Tufprene (maleic anhydride-modified SBS, 912 (manufactured by Asahi Kasei)), and Septon (maleic anhydride-modified SEPS (manufactured by Kuraray)).

The amount of polystyrene in the styrene block polymer in the resin composition of the present invention is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, in the resin composition. On the other hand, the upper limit of the content of the elastomer is preferably 3% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.8% by mass or less. By setting it in such a range, it is possible to achieve high light transmittance while maintaining excellent flame retardancy.

The content of the elastomer in the resin composition of the present invention can be set to 1.0 to 3.0% by mass in the resin composition.
The resin composition of the present invention may contain only one kind of elastomer, or may contain two or more kinds. When two or more kinds are contained, the total amount is preferably in the above range.

It is preferable that the resin composition of the present invention is substantially free of elastomers other than the styrene block polymer. "Substantially free" means that the content of elastomers other than the styrene block polymer is 10% by mass or less of the blended amount of the styrene block polymer, preferably 5% by mass or less, and more preferably 1% by mass or less.

<Light-transmitting dye>
The resin composition of the present invention contains a light-transmitting dye.
The light-transmitting dye used in the present invention is usually a black dye, and specific examples thereof include naphthalocyanine, aniline black, phthalocyanine, porphyrin, perinone, perylene, quaterrylene, azo dye, anthraquinone, pyrazolone, squaric acid derivatives, and immonium dyes.
Examples of commercially available products include colorants e-BIND (trade name) LTW-8731H (model number) and e-BIND (trade name) LTW-8701H (model number) manufactured by Orient Chemical Industry Co., Ltd., colorants Plast Yellow 8000, Plast Red M 8315, and Oil Green 5602 manufactured by Arimoto Chemical Industry Co., Ltd., colorants Macrolex Yellow 3G, Macrolex Red EG, and Macrolex Green 3 manufactured by LANXESS Corporation, and Lumogen K0087 (formerly Lumogen FK4280) and Lumogen K0088 (formerly Lumogen FK4281) manufactured by BASF Color & Effects Japan Ltd.
In particular, when a polyamide resin composition containing at least one of pyrazolone, perinone, perylene, and anthraquinone as a light-transmitting dye is used, color transfer of the resulting molded article after a wet heat test can be effectively suppressed.
The content of the light-transmitting dye in the resin composition of the present invention is preferably 0.001 parts by mass or more, more preferably 0.006 parts by mass or more, and may be 0.018 parts by mass or more, 0.024 parts by mass or more, 0.030 parts by mass or more, or 0.050 parts by mass or more, relative to 100 parts by mass of the resin composition. The upper limit of the content of the light-transmitting dye is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 1.0 parts by mass or less, and may be 0.20 parts by mass or less, 0.10 parts by mass or less, or 0.060 parts by mass or less.
The content of the light-transmitting dye in the resin composition of the present invention is preferably 0.01% by mass or more, more preferably 0.05% by mass or more. The upper limit of the content of the light-transmitting dye is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 1.0% by mass of the resin composition.
The light-transmitting dye may be contained in only one kind or in two or more kinds. When two or more kinds are contained, it is preferable that the total amount is in the above range.
Furthermore, the resin composition of the present invention preferably contains substantially no carbon black. "Substantially no carbon black" means, for example, that the carbon black content is 0.0001 mass % or less of the resin composition.

<Polyphenylene ether resin (PPE)>
The resin composition of the present invention preferably contains a polyphenylene ether resin. By containing a polyphenylene ether resin, it becomes possible to effectively suppress burrs on a molded product.
The polyphenylene ether resin is preferably a maleic anhydride-modified polyphenylene ether resin. The amount of maleic anhydride in the maleic anhydride-modified polyphenylene ether resin is 0.01 to 1.0 mass %, preferably 0.1 to 0.7 mass %, calculated as the amount of maleic acid. By setting the amount in this range, high mechanical strength can be achieved.
The amount of maleic anhydride in the maleic anhydride-modified polyphenylene ether resin refers to the mass of the maleic anhydride used to modify the polyphenylene ether resin and which reacts with the polyphenylene ether resin, converted into the amount of maleic acid.

Examples of polyphenylene ether resins include poly(2,6-dimethyl-1,4-phenylene) ether, poly(2,6-diethyl-1,4-phenylene) ether, poly(2,6-dipropyl-1,4-phenylene) ether, poly(2-methyl-6-ethyl-1,4-phenylene) ether, and poly(2-methyl-6-propyl-1,4-phenylene) ether. In particular, poly(2,6-dimethyl-1,4-phenylene) ether is preferred.
The polyphenylene ether resin preferably has an intrinsic viscosity of 0.2 to 0.6 dL/g, more preferably 0.3 to 0.5 dL/g, measured in chloroform at a temperature of 30° C. By making the intrinsic viscosity 0.2 dL/g or more, impact resistance tends to be improved, while by making it 0.6 dL/g or less, moldability and appearance tend to be improved. The intrinsic viscosity within the above range may be adjusted by using two or more polyphenylene ether resins having different intrinsic viscosities in combination.

The content of the polyphenylene ether resin is preferably 1.0% by mass or more of the resin composition, more preferably 2.5% by mass or more, even more preferably 5% by mass or more, even more preferably 7% by mass or more, even more preferably 8.5% by mass or more, and even more preferably 9.0% by mass or more. The upper limit is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, even more preferably 12.0% by mass or less, and even more preferably 11.0% by mass or less. By making it 20.0% by mass or less, the laser weldability can be increased even if the total energy input during laser welding is reduced.
The resin composition of the present invention may contain only one type of polyphenylene ether resin, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

It is more preferable that the resin composition of the present invention contains both a block polymer and a polyphenylene ether-based resin. In particular, the present invention contains a polystyrene block polymer and a polyphenylene ether-based resin, and the mass ratio of the styrene block polymer to the polyphenylene ether-based resin is preferably 1:1 to 1:35, more preferably 1:10 to 1:20, and even more preferably 1:12 to 1:18. By using such a mass ratio, the effects of the present invention are more effectively exhibited.

<Release Agent>
The resin composition of the present invention 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, and light amides. Of these, 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.
For details of the release agent, please refer to paragraphs 0055 to 0061 of JP2018-095706A, the contents of which are incorporated herein by reference.
When the resin composition of the present invention contains a release agent, the content thereof in the resin composition is preferably 0.05 to 3 mass%, more preferably 0.1 to 0.8 mass%, and further preferably 0.2 to 0.6 mass%.
The resin composition of the present invention may contain only one type of release agent, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

<Glass fiber>
The resin composition of the present invention preferably contains glass fibers.
The glass fibers are made of a glass composition such as A-glass, C-glass, E-glass, R-glass, or S-glass, and E-glass (alkali-free glass) is particularly preferred.

The glass fiber used in the resin composition of the present invention 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" in which a single fiber or a plurality of twisted fibers are continuously wound up, "chopped strand" having a cut length (number average fiber length) of 1 to 10 mm, and "milled fiber" having a crushed length (number average fiber length) of 10 to 500 μm. Such glass fibers are commercially available from Asahi Fiber Glass Co., Ltd. under the trade names "Glaslon Chopped Strand" and "Glaslon Milled Fiber," and are easily available. Glass fibers of different forms can also be used in combination.

In the present invention, glass fibers having an irregular cross-sectional shape are also preferred. The irregular cross-sectional shape has a flattening ratio, expressed as the major axis/minor axis ratio (D2/D1) where D2 is the major axis of a cross section perpendicular to the longitudinal direction of the fiber and D1 is the minor axis, of, for example, 1.5 to 10, preferably 2.5 to 10, more preferably 2.5 to 8, and even more preferably 2.5 to 5. For such flattened glass, see paragraphs 0065 to 0072 of JP 2011-195820 A, the contents of which are incorporated herein by reference.

The glass fiber in the present invention may be glass beads. Glass beads are spherical with an outer diameter of 10 to 100 μm, and are readily available, for example, from Potters Ballotini under the product name "EGB731." Glass flakes are flakes with a thickness of 1 to 20 μm and a side length of 0.05 to 1 mm, and are readily available, for example, from Nippon Sheet Glass Co., Ltd. under the product name "Fleca."

The glass fibers used in the present invention are particularly preferably glass fibers having a weight average fiber diameter of 1 to 20 μm and a cut length (number average fiber length) of 1 to 10 mm. When the cross section of the glass fibers is flat, the weight average fiber diameter is calculated as the weight average fiber diameter in a circle having the same area.
The glass fibers used in the present invention may be bundled with a bundling agent. In this case, the bundling agent is preferably an acid-based bundling agent containing maleic anhydride, a urethane-based bundling agent, an epoxy-based bundling agent, or the like.

The content of glass fiber in the resin composition of the present invention is preferably 20% by mass or more, more preferably 25% by mass or more, even more preferably 30% by mass or more, even more preferably 35% by mass or more, and even more preferably 40% by mass or more. The content of glass fiber in the resin composition of the present invention is preferably 60% by mass or less, more preferably 55% by mass or less, and may be less than 50% by mass. By blending glass fiber in the above range, it is possible to maintain a higher light transmittance.
The resin composition of the present invention may contain only one type of glass fiber, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is within the above range.

<Other Ingredients>
The resin composition of the present invention may contain other components within the scope of the present invention. Examples of such additives include nucleating agents, fillers other than glass fibers, light stabilizers, antioxidants, ultraviolet absorbers, fluorescent brighteners, drip prevention agents, antistatic agents, antifogging agents, antiblocking agents, flow improvers, plasticizers, dispersants, and antibacterial agents. These components may be used alone or in combination of two or more.
In addition, the contents of the polyamide resin (preferably a xylylenediamine-based polyamide resin), flame retardant, elastomer, and light-transmitting dye, as well as glass fiber and other additives, are adjusted so that the total of each component in the resin composition of the present invention is 100 mass %.

<Preferable blend form of resin composition>
The resin composition of the present invention preferably comprises a xylylenediamine-based polyamide resin, a phosphazene-based flame retardant, a styrene block polymer, a polyphenylene ether-based resin, and zinc oxide, the content of the styrene block polymer being 1-2% by mass of the resin composition, the xylylenediamine constituting the xylylenediamine-based polyamide resin comprises metaxylylenediamine and paraxylylenediamine, the α,ω-linear aliphatic dicarboxylic acid having 4-20 carbon atoms constituting the xylylenediamine-based polyamide resin comprises adipic acid, the content of the flame retardant auxiliary is 1.1-6.0% by mass of the resin composition, and the content of the polyamide resin other than the xylylenediamine-based polyamide resin in the resin composition is 4% by mass or less of the resin composition. By making such a composition, each component is well balanced, and high flame retardancy is maintained while maintaining high light transmittance and achieving higher Charpy impact strength.

<Characteristics of Resin Composition>
The resin composition of the present invention, when molded to a thickness of 4 mm, has an unnotched Charpy impact strength according to ISO 179 of 50 kJ/ ^m2 or more, and a notched Charpy impact strength according to ISO 179 of 10 kJ/ ^m2 or more. The notched Charpy impact strength is preferably 11 kJ/ ^m2 or more. Since the molded article obtained from the resin composition of the present invention has a high Charpy impact strength, it can be preferably used in applications where impact resistance is required. In particular, the present invention is highly valuable in that the above Charpy impact strength can be achieved while incorporating a flame retardant.
The upper limit of the unnotched Charpy impact strength is not particularly specified, but even if it is 70 kJ/ ^m2 or less, or even if it is 60 kJ/ ^m2 or less, it is a sufficiently practical level. Also, the notched Charpy impact strength is not particularly specified, but even if it is 20 kJ/ ^m2 or less, or even if it is ¹⁵ kJ/m2 or less, it is a sufficiently practical level.
The resin composition of the present invention has a light transmittance at a wavelength of 940 nm of 30% or more, preferably 35% or more, when molded to a thickness of 1 mm. The upper limit may be 100%, but in practice, even if it is 50% or less, the required performance is sufficiently satisfied.
Furthermore, the resin composition of the present invention, when molded to a thickness of 0.75 mm, meets the UL94 flammability test (flammability and heat aging resistance) of V-0.
Furthermore, the resin composition of the present invention preferably conforms to V-0 in the UL94 flammability test after being molded to a thickness of 0.75 mm and placed in an environment at 70° C. for 168 hours.
Details of the UL94 flammability test are as described in the Examples below.

<Method of producing resin composition>
The method for producing the resin composition of the present invention is not particularly limited, but a method using a single-screw or twin-screw extruder having a vent port for volatilization as a kneader is preferred. The polyamide resin component, glass fiber, and other additives to be mixed as necessary may be fed to the kneader all at once, or other components may be fed to the polyamide resin component in sequence. The glass fiber is preferably fed from the middle of the extruder in order to prevent it from being crushed during kneading. Two or more components selected from each component may be mixed and kneaded in advance.
In the present invention, the light-transmitting dye may be prepared in advance as a master batch of a polyamide resin or the like, and then kneaded with other components (a polyamide resin (preferably a xylylenediamine-based polyamide resin) or the like) to prepare the resin composition of the present invention.

There are no particular limitations on the method for producing a molded article using the resin composition of the present invention, and molding methods commonly used for thermoplastic resins, such as injection molding, blow molding, extrusion molding, and press molding, can be applied. In this case, a particularly preferred molding method is injection molding because of its good fluidity. In injection molding, it is preferable to control the resin temperature to 250 to 300°C.

<Kit>
The present invention also discloses a kit comprising the above resin composition and a light-absorbing resin composition comprising a thermoplastic resin and a light-absorbing dye. The kit of the present invention is preferably used for producing a molded article by laser welding.
That is, the resin composition included in the kit serves as a light-transmitting resin composition, and a molded article made from the light-transmitting resin composition serves as a transmissive resin member for laser light during laser welding, whereas a molded article made from the light-absorbing resin composition serves as an absorbing resin member for laser light during laser welding.

<<Light-absorbing resin composition>>
The light-absorbing resin composition used in the present invention contains a thermoplastic resin and a light-absorbing dye.
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., and from the viewpoint of good compatibility with the resin composition, polyamide resin, polyester resin, and polycarbonate resin are particularly preferred, and polyamide resin is more preferred. The thermoplastic resin may be one type or two or more types.
The type of polyamide resin used in the light absorbing resin composition is not particularly limited, but the above xylylenediamine polyamide resin is preferred.
It may also contain an inorganic filler. Examples of the inorganic filler include glass fiber, carbon fiber, silica, alumina, talc, carbon black, and fillers capable of absorbing laser light, such as inorganic powder coated with a material that absorbs laser light, and glass fiber is preferred. The glass fiber is synonymous with the glass fiber that may be blended in the resin composition of the present invention, and the preferred range is also the same.
The light absorbing dye has a maximum absorption wavelength in the range of the wavelength of the irradiated laser light, that is, in the present invention, a wavelength range of 800 nm to 1100 nm, and examples thereof 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, and 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. Two or more of these light absorbing dyes may be used in combination. The content of the light absorbing dye is preferably 0.01 to 30 parts by mass per 100 parts by mass of the resin component.

In the kit of the present invention, it is preferable that 80% by mass or more of the components excluding the light-transmitting dye in the resin composition and the components excluding the light-absorbing dye in the light-absorbing resin composition are common to each other, more preferably 90% by mass or more, and even more preferably 95 to 100% by mass are common to each other.

<<Laser welding method>>
Next, the laser welding method will be described. In the present invention, a molded article can be manufactured by laser welding a molded article (transmissive resin member) obtained by molding the resin composition of the present invention and a molded article (absorbent resin member) obtained by molding the above-mentioned light-absorbing resin composition. By laser welding, the transparent resin member and the absorbent resin member can be firmly welded without using an adhesive.
The shape of the member is not particularly limited, but since the members are used by joining them together by laser welding, the shape usually has at least a surface contact area (flat surface, curved surface). In laser welding, the laser light transmitted through the transparent resin member is absorbed by the absorbing resin member, melts, and the two members are welded together. The molded product of the resin composition of the present invention has high transparency to laser light, so it can be preferably used as a transparent resin member. Here, the thickness of the member through which the laser light transmits (thickness in the laser transmission direction at the part through which the laser light transmits) can be appropriately determined taking into account the application, the composition of the resin composition, and other factors, and is, for example, 5 mm or less, preferably 4 mm or less.

The laser light source used for laser welding can be determined according to the absorption wavelength of the light of the light-absorbing dye, and a laser with a wavelength in the range of 800 to 1100 nm is preferable; for example, a semiconductor laser or fiber laser can be used.

More specifically, for example, when welding a transparent resin member and an absorbing resin member, first, the parts to be welded of both are brought into contact with each other. At this time, it is preferable that the welded parts of both are in surface contact, and they may be flat surfaces, curved surfaces, or a combination of flat surfaces and curved surfaces. Next, laser light is irradiated from the transparent resin member side. At this time, if necessary, a lens may be used to focus the laser light on the interface between the two. The focused beam passes through the transparent resin member and is absorbed near the surface of the absorbing resin member, generating heat and melting it. Next, the heat is transmitted to the transparent resin member by thermal conduction and melts it, forming a molten pool at the interface between the two, and after cooling, the two are joined together.
The molded article in which the permeable resin member and the absorptive resin member are welded in this manner has high weld strength. Note that the molded article in the present invention includes not only finished products and parts, but also members that form part of these products and parts.

The molded product obtained by laser welding in the present invention has good mechanical strength, high welding strength, and little damage to the resin due to laser light irradiation, so it can be used in a variety of applications, such as various storage containers, electrical and electronic equipment parts, office automation (OA) equipment parts, home appliance parts, machine mechanism parts, and vehicle mechanism parts. In particular, it can be suitably used for food containers, pharmaceutical containers, oil and fat product containers, hollow parts for vehicles (various tanks, intake manifold parts, camera housings, etc.), electrical parts for vehicles (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 resin composition and kit of the present invention are suitable for vehicle-mounted camera modules.

The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, processing contents, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[material]
<Polyamide resin>
MP6: Polymeta-para-xylylene adipamide, synthesized according to the following method.
PA66: Polyamide 66, Solvay, STAVAMID26AE1K
PA12: Polyamide 12, Manufacturer: M-Chemie Japan, Product number: Grilamid L20G

<<Synthesis example of MP6>>
Adipic acid was dissolved by heating in a reaction vessel under a nitrogen atmosphere, and then the contents were stirred while gradually dropping a mixed diamine of paraxylylenediamine (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and metaxylylenediamine (manufactured by Mitsubishi Gas Chemical Co., Ltd.) in a molar ratio of 3:7 under pressure (0.35 MPa) so that the molar ratio of diamine to adipic acid (manufactured by Rhodia Co., Ltd.) became about 1:1, while raising the temperature to 270°C. After 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. The contents were then taken out in the form of strands and pelletized with a pelletizer to obtain a xylylenediamine-based polyamide resin (MP6).

<Maleic acid modified PPE>
PME-80 (Mitsubishi Engineering Plastics Corporation)

Kraton FG1901X: Manufactured by Kraton Japan, contains 30% maleic anhydride modified polystyrene-poly(ethylene/butylene)-polystyrene block copolymer by mass, 1.7% maleic anhydride content, and 30% polystyrene content by mass.

Release agent (CS8CP): calcium montanate, manufactured by Nitto Kasei Kogyo Co., Ltd. Light-transmitting dye (LTW-8701H): e-BIND LTW-8701H, manufactured by Orient Chemical Industry Co., Ltd., masterbatch of polyamide 66 and light-transmitting dye Glass fiber (296GH): ECS 03T-296GH, manufactured by Nippon Electric Glass Co., Ltd.
Flame retardant (Rabitor FP-110): Phosphazene compound, Fushimi Pharmaceutical Co., Ltd. Flame retardant assistant (Firebreak ZB): Zinc borate, Rio Tinto Minerals Asia Pte ltd.

[Examples 1 to 3, Comparative Examples 1 to 8]
<Compound>
Resin compositions (pellets for forming permeable resin members) shown in Table 1 or Table 2 described below were produced.
Specifically, the components other than glass fiber were weighed out in the proportions (units: parts by mass) shown in Table 1 or Table 2 described later, and then dry-blended. The components were then fed from the screw root of a twin-screw extruder (Toshiba Machine Co., Ltd., TEM26SS) using a twin-screw cassette weighing feeder (Kubota Corporation, CE-W-1-MP). The glass fiber was fed from the side of the extruder using a vibrating cassette weighing feeder (Kubota Corporation, CE-V-1B-MP), and melt-kneaded with the resin components and the like to obtain pellets for forming a permeable resin member. The temperature of the extruder was set to 280°C.

<Charpy impact strength>
The pellets obtained by the above-mentioned manufacturing method were dried at 120°C for 4 hours, and then injection molded into 4 mm thick ISO tensile test pieces using NEX140III manufactured by Nissei Plastic Industrial Co., Ltd. The molding was performed at a cylinder temperature of 280°C and a mold surface temperature of 130°C.
The notched and unnotched Charpy impact strengths of the obtained ISO tensile test pieces were measured at 23° C. in accordance with ISO 179. The unit of Charpy impact strength was expressed in kJ/ ^m2 .

<Light transmittance>
The pellets obtained by the above-mentioned manufacturing method were dried at 120°C for 4 hours, and then injection molded into test pieces having a thickness of 1 mm using NEX140III manufactured by Nissei Plastic Industrial Co., Ltd. The molding was performed at a cylinder temperature of 280°C and a mold surface temperature of 130°C.
The light transmittance (unit: %) of the 1 mm thick test piece obtained above at a wavelength of 940 nm was measured using an ultraviolet, visible, near infrared spectrophotometer UV-3100PC manufactured by Shimadzu Corporation.

<UL94 Flammability Test (Flammability)>
The pellets obtained by the above-mentioned production method were dried at 120°C for 4 hours, and then molded into test pieces having a length of 125 mm, a width of 13 mm, and a thickness of 0.75 mm using an injection molding machine (FN-3000, screw diameter 40 mm, manufactured by Nissei Plastic Industrial Co., Ltd.) at a cylinder temperature of 280°C and a mold temperature of 130°C.
The resulting test pieces were left in an environment of 23° C. for 48 hours (normal temperature) and in an environment of 70° C. for 168 hours (thermal aging), and then the flammability was measured. The flammability was evaluated according to the UL94 flammability test (a standard established by Under Writers Laboratories Inc., USA).

<Ash content (600°C)>
The mass of the crucible, the mass of the molded product, and the mass of the molded product placed in the crucible were each measured, and the product was treated in an electric furnace at 600° C. for 2 hours, and the mass was measured again. The ash content was calculated from these values.
The units are shown in mass %.

As is clear from the above results, the resin composition of the present invention was able to achieve high Charpy impact strength while achieving high light transmittance and excellent flame retardancy (Examples 1 to 3).
On the other hand, the resin compositions of the comparative examples could not achieve high unnotched Charpy impact strength (Comparative Examples 1 to 8).

The resin composition of Example 1 was treated in the same manner as above, except that no light-transmitting dye was added, and 6 parts by mass of a carbon black master batch (PA-0895, manufactured by Nikko Bix Co., Ltd.) was added, to obtain pellets for forming an absorbent resin member. The pellets for forming a transparent resin member obtained in Example 1 and the pellets for forming an absorbent resin member were laser welded in accordance with the description in paragraphs 0072 and 0073 and FIG. 1 of JP 2018-168346 A. Appropriate laser welding was confirmed.

Claims (7)

20 to 40 mass % of a xylylenediamine-based polyamide resin that is composed of diamine-derived structural units and dicarboxylic acid-derived structural units, in which 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms;
3% by mass or more and 20% by mass or less of a phosphazene-based flame retardant;
1.0 to 3.0% by mass of a maleic anhydride-modified styrene block polymer which is an elastomer ;
1.0% by mass or more and 20.0% by mass or less of a polyphenylene ether resin;
Zinc oxide : 6.1% by mass or more and 8.9% by mass or less ;
Glass fiber and
A resin composition comprising a light-transmitting dye,
The light-transmitting dye is contained in an amount of 0.001 parts by mass or more and 5.0 parts by mass or less relative to 100 parts by mass of the resin composition,
When the resin composition is molded into a thickness of 1 mm, the light transmittance at a wavelength of 940 nm is 30% or more and less than 100%,
When the resin composition is molded to a thickness of 4 mm, the unnotched Charpy impact strength according to ISO 179 is 50 kJ/ ^m2 or more and 70 kJ/ ^m2 or less, and the notched Charpy impact strength according to ISO 179 is 10 kJ/ ^m2 or more and 20 kJ/ ^m2 or less,
When the resin composition is molded to a thickness of 0.75 mm, it meets the UL94 flammability test criteria of V-0.
the content of polystyrene in the maleic anhydride-modified styrene block polymer as the elastomer is 0.3 to 0.8 % by mass of the resin composition;
The xylylenediamine includes metaxylylenediamine and paraxylylenediamine, and the α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms includes adipic acid,
the content of polyamide resins other than the xylylenediamine-based polyamide resin in the resin composition is 4% by mass or less of the resin composition;
The content of the glass fiber in the resin composition is 40% by mass or more and 50% by mass or less,
The glass fibers are E-glass fibers,
Resin composition for laser welding . 2. The resin composition for laser welding according to claim 1, wherein a mass ratio of the maleic anhydride modified styrene block polymer as the elastomer to the polyphenylene ether resin is 1:1 to 1:35. 3. The resin composition for laser welding according to claim 1, wherein the polyphenylene ether resin is modified with maleic anhydride. A molded article for laser welding formed from the resin composition for laser welding according to claim 1 or 2. 3. A kit for laser welding comprising the resin composition for laser welding according to claim 1 or 2, and a light-absorbing resin composition containing a thermoplastic resin and a light-absorbing dye. 3. A method for producing a laser-welded molded product, comprising laser welding a molded product obtained by molding the resin composition for laser welding according to claim 1 or 2 and a molded product obtained by molding a light-absorbing resin composition containing a thermoplastic resin and a light-absorbing dye. A laser weldable molded product obtained by molding the resin composition for laser welding according to claim 1 or 2, or the kit according to claim 4.