JP5912573B2 - Polyester resin composition for laser marking and molded product - Google Patents

Description

  The present invention relates to a polyester resin composition for laser marking and a molded product. More specifically, the present invention relates to a laser marking that is easy to perform, excellent in printability (contrast) by laser marking, and light resistance of the marked mark. It is related with the polyester resin composition for laser marking which is excellent also in the molded object which shape | molds it.

  Thermoplastic polyester resins represented by polybutylene terephthalate and polyethylene terephthalate are excellent in mechanical strength, chemical resistance, electrical insulation, etc., and have excellent heat resistance, moldability, and recyclability. Therefore, it is widely used for electrical and electronic equipment parts, automobile parts, other electrical parts, machine parts and the like.

  In electrical and electronic equipment parts, etc., the product type, production lot number, etc. are often printed on the outer surface of the product. As a printing method for this purpose, laser marking has been attracting attention, in which a molded product containing a filler that changes color upon irradiation with energy by laser light is irradiated with laser light for printing (including labels, patterns, etc.).

As this polyester-based resin material for laser marking, for example, Patent Document 1 discloses a self-extinguishing polybutylene terephthalate compounded with copper hydroxide-phosphate or molybdenum oxide, and Patent Document 2 discloses A resin composition having a limiting oxygen index of 22% or more in which a flame retardant is blended with alkylene terephthalate is described. Furthermore, Patent Document 3 discloses a polyester resin composition comprising a thermoplastic polyester resin, a brominated flame retardant, an antimony flame retardant auxiliary, and carbon black and / or graphite.
However, none of these resin compositions are sufficiently satisfactory in terms of printability by laser marking and light resistance of the marked marks, and aggregates are formed due to aggregation of flame retardants and the like. In some cases, the appearance of the molded product is poor.

Japanese Patent No. 2947878 Japanese Patent No. 2862413 Japanese Patent No. 2735956

  An object of the present invention is to provide a polyester resin composition for laser marking which is excellent in printability by laser marking, and further excellent in light resistance and appearance of a molded product.

The present inventor has found that a polyester resin composition containing a specific amount of brominated polystyrene and an antimony compound can solve the above-mentioned problems, and has completed the present invention.
That is, according to the present invention, the following polyester resin composition for laser marking and molded article are provided.

[1] For laser marking, comprising 5 to 30 parts by mass of brominated polystyrene (B) and 1 to 20 parts by mass of antimony compound (C) with respect to 100 parts by mass of the thermoplastic polyester resin (A). Polyester resin composition.
[2] The polyester resin composition for laser marking according to [1], further comprising 0.1 to 5 parts by mass of polycarbonate (D) and / or talc (E).
[3] Furthermore, the titanium oxide (F) is contained in an amount of 0.1 to 20 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A), as described in [1] or [2] above A polyester resin composition for laser marking.
[4] The glass fiber (G) is further contained in an amount of 10 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A). A polyester resin composition for laser marking.
[5] Any of the above [1] to [4], further comprising 0.1 to 5 parts by mass of the anti-dripping agent (H) with respect to 100 parts by mass of the thermoplastic polyester resin (A). A polyester resin composition for laser marking according to claim 1.
[6] The polyester resin composition for laser marking according to any one of the above [1] to [5], wherein the antimony compound (C) is antimony trioxide.
[7] The polyester resin composition for laser marking according to any one of the above [1] to [6], wherein the polycarbonate (D) is a brominated polycarbonate.
[8] The polyester resin composition for laser marking according to any one of [1] to [7], wherein the main component of the thermoplastic polyester resin (A) is polybutylene terephthalate.

[9] A molded article obtained by molding the laser marking polyester resin composition according to any one of [1] to [8].
[10] The molded body according to [9], which is a casing of an electric / electronic device or a base, an element substrate, or a casing of a lighting device.
[11] The molded article according to [9] or [10], wherein the surface is laser-marked.

The polyester resin composition for laser marking of the present invention can be easily marked by laser, is excellent in printability (contrast) by laser marking, and is excellent in light resistance and appearance of a molded product.
For this reason, the polyester resin composition for laser marking of this invention can be used especially suitably for the housing | casing of an electrical / electronic device, or a nozzle | cap | die, an element board | substrate, or a housing | casing of the apparatus for illumination, for example.
And since the mark made by laser marking on the surface of the molded body obtained by molding the polyester resin composition of the present invention is excellent in light resistance, stable printing and symbols can be maintained clearly, and over a long period of time. Identify, manage and use products.

About the mechanism which expresses such an effect of the present invention, it guesses as follows.
That is, it turned out that brominated polystyrene (B) is excellent in laser marking property compared with other brominated flame retardants.
In particular, when polytetrafluoroethylene, which is an anti-drip agent (H), is blended, these and brominated polystyrene (B) are likely to aggregate and exist in the molded product as aggregates. There may be a problem that the appearance deteriorates. Furthermore, when carbon black is blended for the purpose of improving the laser marking property, the aggregate may be more noticeable. In such a case, by blending polycarbonate (D) or talc (E), these act as a dispersant, making it difficult for the brominated polystyrene (B) to agglomerate, resulting in a molded product having no appearance and excellent appearance. It is thought that.

[1. Summary of the Invention]
The polyester resin composition for laser marking of the present invention contains 5 to 30 parts by mass of brominated polystyrene (B) and 1 to 20 parts by mass of antimony compound (C) with respect to 100 parts by mass of the thermoplastic polyester resin (A). It is characterized by doing.

Hereinafter, the contents of the present invention will be described in detail.
The description of each constituent element described below may be made based on typical embodiments and specific examples of the present invention, but the present invention is interpreted to be limited to such embodiments and specific examples. It is not a thing. In the present specification, “to” is used to mean that the numerical values described before and after it are used as the lower limit and the upper limit, and “ppm” means “mass ppm”.

[2. Thermoplastic polyester resin (A)]
The thermoplastic polyester resin (A) which is the main component of the polyester resin composition of the present invention is obtained by polycondensation of a dicarboxylic acid compound and a dihydroxy compound, polycondensation of an oxycarboxylic acid compound or polycondensation of these compounds. Polyester, which may be homopolyester or copolyester.

As the dicarboxylic acid compound constituting the thermoplastic polyester resin (A), an aromatic dicarboxylic acid or an ester-forming derivative thereof is preferably used.
Aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-2, 2′-dicarboxylic acid, Biphenyl-3, 3'-dicarboxylic acid, biphenyl-4, 4'-dicarboxylic acid, diphenyl ether-4, 4'-dicarboxylic acid, diphenylmethane-4, 4'-dicarboxylic acid, diphenylsulfone-4, 4'-dicarboxylic acid , Diphenylisopropylidene-4,4′-dicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4′-dicarboxylic acid, anthracene-2,5-dicarboxylic acid, anthracene-2,6-dicarboxylic acid, p -Terphenylene-4,4'-dicarboxylic acid, pyridine-2,5-dicarboxylic acid, etc. But terephthalic acid can be preferably used.

These aromatic dicarboxylic acids may be used as a mixture of two or more. As is well known, these can be used in polycondensation reactions as ester-forming derivatives such as dimethyl esters in addition to free acids.
If the amount is small, together with these aromatic dicarboxylic acids, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, dodecanedioic acid, sebacic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and 1 One or more alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid can be mixed and used.

Examples of the dihydroxy compound constituting the thermoplastic polyester resin (A) include ethylene glycol, propylene glycol, butanediol, hexylene glycol, neopentyl glycol, 2-methylpropane-1,3-diol, diethylene glycol, and triethylene glycol. Examples thereof include aliphatic diols, alicyclic diols such as cyclohexane-1,4-dimethanol, and mixtures thereof. If the amount is small, one or more long-chain diols having a molecular weight of 400 to 6,000, that is, polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol, and the like may be copolymerized.
In addition, aromatic diols such as hydroquinone, resorcin, naphthalenediol, dihydroxydiphenyl ether, and 2,2-bis (4-hydroxyphenyl) propane can also be used.

  In addition to the above-mentioned bifunctional monomers, trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, and trimethylolpropane are introduced to introduce a branched structure, and fatty acids are used for molecular weight control. A small amount of a monofunctional compound can be used in combination.

  As the thermoplastic polyester resin (A), usually, a resin mainly composed of polycondensation of a dicarboxylic acid and a diol, that is, a resin comprising 50% by mass, preferably 70% by mass or more of the entire resin, is composed of this polycondensate. The dicarboxylic acid is preferably an aromatic carboxylic acid, and the diol is preferably an aliphatic diol.

Of these, polyalkylene terephthalate in which 95 mol% or more of the acid component is terephthalic acid and 95 mass% or more of the alcohol component is an aliphatic diol is preferable. Typical examples are polybutylene terephthalate and polyethylene terephthalate. These are preferably close to homopolyester, that is, 95% by mass or more of the total resin is composed of a terephthalic acid component and a 1.4-butanediol or ethylene glycol component.
In the polyester resin composition of the present invention, the main component is particularly preferably polybutylene terephthalate.

  The intrinsic viscosity of the thermoplastic polyester resin (A) is preferably 0.5 to 2 dl / g. From the viewpoint of moldability and mechanical properties, those having an intrinsic viscosity in the range of 0.6 to 1.5 dl / g are more preferable. If the intrinsic viscosity is lower than 0.5 dl / g, the resulting resin composition tends to have a low mechanical strength. On the other hand, if it is higher than 2 dl / g, the fluidity of the resin composition may deteriorate and the moldability may deteriorate. The intrinsic viscosity of the thermoplastic polyester resin is measured at 30 ° C. in a 1: 1 (mass ratio) mixed solvent of tetrachloroethane and phenol.

[3. Brominated polystyrene (B)]
Examples of the brominated polystyrene (B) contained in the polyester resin composition of the present invention include brominated polystyrene containing a repeating unit represented by the following general formula (1).

（式（１）中、ｔは１〜５の整数であり、ｎは繰り返し単位の数である。）

(In formula (1), t is an integer of 1 to 5, and n is the number of repeating units.)

  In the general formula (1), the CH group to which brominated benzene is bonded may be substituted with a methyl group. The brominated polystyrene may be a copolymer obtained by copolymerizing another vinyl monomer. Examples of the vinyl monomer in this case include styrene, α-methylstyrene, acrylonitrile, methyl acrylate, butadiene, and vinyl acetate. Moreover, brominated polystyrene may be used as a single substance or a mixture of two or more different structures, and may contain units derived from styrene monomers having different numbers of bromines in a single molecular chain.

  Specific examples of brominated polystyrene include, for example, poly (4-bromostyrene), poly (2-bromostyrene), poly (3-bromostyrene), poly (2,4-dibromostyrene), poly (2,6 -Dibromostyrene), poly (2,5-dibromostyrene), poly (3,5-dibromostyrene), poly (2,4,6-tribromostyrene), poly (2,4,5-tribromostyrene) , Poly (2,3,5-tribromostyrene), poly (4-bromo-α-methylstyrene), poly (2,4-dibromo-α-methylstyrene), poly (2,5-dibromo-α- Methyl (styrene), poly (2,4,6-tribromo-α-methylstyrene), poly (2,4,5-tribromo-α-methylstyrene) and the like, and poly (2,4,6-tribromostyrene). And poly (2,4,5-tribromostyrene) and polydibromostyrene and polytribromostyrene containing an average of 2 to 3 bromine groups in the benzene ring are particularly preferably used.

Brominated polystyrene is usually produced by brominating polystyrene. For example, it is produced by reacting bromine or bromine chloride with polystyrene in a chlorinated hydrocarbon solvent (for example, methylene chloride, dichloroethane, etc.) in the presence of a Lewis basic acid catalyst.
On the other hand, brominated styrene monomers (for example, 2,4-dibromostyrene, 2,6-dibromostyrene, 2,5-dibromostyrene, 3,5-dibromostyrene, 2,4,6-tribromostyrene, 2 , 4,5-tribromostyrene, 2,3,5-tribromostyrene, etc.).
The brominated polystyrene in the present invention may be any of the above bromination reaction or polymerization method, but there is a problem of bromination reaction other than the aromatic ring and the content of free bromine (atom or compound). Less bromine polystyrene (atomic or compound) generated in the subsequent heating and molding process is preferred, and brominated polystyrene by polymerization is more preferred.

In the brominated polystyrene, the number n (average polymerization degree) of the repeating units in the general formula (1) is preferably 30 to 1,500, more preferably 150 to 1,000, particularly 300 to 800. Is preferred. If the average degree of polymerization is less than 30, blooming tends to occur. On the other hand, if it exceeds 1,500, poor dispersion tends to occur and the mechanical properties tend to deteriorate. The mass average molecular weight (Mw) of brominated polystyrene is preferably about 10,000 to 200,000, more preferably 10,000 to 100,000, and still more preferably 10,000 to 70,000. It is.
In particular, in the case of the brominated product of polystyrene described above, the mass average molecular weight (Mw) is preferably 50,000 to 70,000, and in the case of brominated polystyrene by a polymerization method, the mass average molecular weight (Mw) is 10 It is preferable that it is about 3,000-30,000. In addition, a mass average molecular weight (Mw) can be calculated | required as a value of standard polystyrene conversion by GPC measurement.

  The brominated polystyrene (B) preferably has a bromine concentration of 52 to 75% by mass, more preferably 56 to 73% by mass, and still more preferably 57 to 70% by mass. By setting the bromine concentration in such a range, it is easy to maintain good laser marking properties and flame retardancy.

  Content of brominated polystyrene (B) is 5-30 mass parts with respect to 100 mass parts of thermoplastic polyester resins (A). If the content of brominated polystyrene (B) is less than 5 parts by mass, the laser marking properties and flame retardancy tend to be reduced, and if it exceeds 30 parts by mass, the mechanical properties tend to be reduced. The preferable content of brominated polystyrene (B) is 10 to 25 parts by mass, and more preferably 12 to 20 parts by mass.

[4. Antimony compound (C)]
As the antimony compound (C) contained in the polyester resin composition of the present invention, antimony oxide or a double salt of antimony oxide and another metal can be used. Specifically, for example, an oxide such as antimony trioxide (Sb ₂ O ₃ ), antimony tetraoxide (Sb ₂ O ₄ ), antimony pentoxide (Sb ₂ O ₅ ), or an antimonate such as sodium antimonate. Is mentioned.

  Among these, antimony trioxide is preferable from the viewpoint of a synergistic effect with brominated polystyrene.

  Content of an antimony compound (C) is 1-20 mass parts with respect to 100 mass parts of thermoplastic polyester resins (A). When the content of the antimony compound (C) is less than 1 part by mass, the laser marking property and the flame retardancy are deteriorated. When the content is more than 20 parts by mass, the mechanical properties are deteriorated. The content of the antimony compound (C) is preferably 2 to 15 parts by mass, more preferably 3 to 10 parts by mass.

  The brominated polystyrene (B) and the antimony compound (C) have a total mass of bromine atoms derived from the brominated polystyrene (B) in the polyester resin composition and antimony atoms derived from the antimony compound (C). It is preferable to contain so that it may become 5-16 mass%, and 6-15 mass% is more preferable. If it is less than 5% by mass, the laser marking property and flame retardancy tend to be lowered, and if it exceeds 16% by mass, the mechanical strength may be lowered. The mass ratio (Br / Sb) of bromine atoms and antimony atoms is preferably 0.3 to 5, and more preferably 0.3 to 4.

[5. Polycarbonate (D) and / or talc (E)]
The polyester resin composition of the present invention preferably contains polycarbonate (D) and / or talc (E).
As described above, brominated polystyrene (B) may aggregate with each other, especially when a dripping inhibitor (H) such as polytetrafluoroethylene is blended. It tends to be present in the molded product as an aggregate. Further, when carbon black is blended, aggregates tend to be more noticeable. Polycarbonate (D) and talc (E) function as a dispersant, and brominated polystyrene (B) is less likely to aggregate, and exhibits the effect that the generation of aggregates is significantly reduced.

[5.1 Polycarbonate (D)]
Polycarbonate is produced by an interfacial polymerization method in which an aromatic dihydroxy compound is reacted with phosgene or a transesterification method in which an aromatic dihydroxy compound is reacted with a carbonic acid diester. In the present invention, any production method can be used. In the transesterification method, the terminal OH group concentration may be adjusted by reacting the terminal blocking agent, but those subjected to this treatment can also be used. As the polycarbonate (D), an aromatic polycarbonate in which carbons directly bonded to carbonic acid bonds are aromatic carbons is preferable.

  As the raw material aromatic dihydroxy compound, 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A) is mainly used, but other aromatic dihydroxy compounds such as tetramethylbisphenol A, bis (4 -Hydroxyphenyl) -P-diisopropylbenzene, hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, and the like can also be used. In order to impart flame retardancy, it is also possible to use a compound in which a tetraalkylphosphonium sulfonate is bonded to the above aromatic dihydroxy compound, or a polymer or oligomer having a siloxane structure and having a phenolic OH group at both ends. it can.

  In the present invention, polycarbonates derived from bisphenol A, which is a typical commercially available polycarbonate, can be preferably used, but other polycarbonates such as copolymer polycarbonates derived from bisphenol A and other aromatic dihydroxy compounds are used. You can also. Two or more kinds of polycarbonates may be used in combination.

The molecular weight of the polycarbonate (D) is not limited, but is a viscosity average molecular weight (Mv) converted from the solution viscosity measured at a temperature of 20 ° C. using methylene chloride as a solvent, preferably 10,000 to 40,000, More preferably, it is 12,000-32,000. When the viscosity average molecular weight is within this range, the resulting polyester resin composition has good moldability and a molded product having high mechanical strength is easily obtained. The most preferred molecular weight range of the polycarbonate (D) is 14,000 to 30,000.
In the present invention, the viscosity average molecular weight (Mv) of the polycarbonate (D) is determined by measuring the viscosity of the methylene chloride solution of the polycarbonate resin at 20 ° C. using an Ubbelohde viscometer, and calculating the intrinsic viscosity ([η]). The value calculated from the following Schnell viscosity equation is shown.
[Η] = 1.23 × 10 ⁻⁴ Mv ^0.83

  Moreover, it is also preferable to use the brominated polycarbonate obtained from brominated bisphenol A, especially tetrabromobisphenol A, as the polycarbonate (D).

The brominated polycarbonate is preferably a brominated polycarbonate obtained from brominated bisphenol A, particularly tetrabromobisphenol A. Examples of the terminal structure include a 4-t-butylphenyl group and a 2,4,6-tribromophenyl group, and those having a 2,4,6-tribromophenyl group in the terminal group structure are particularly preferable.
Moreover, although the average of the carbonate repeating unit number in a brominated polycarbonate should just be selected and determined suitably, it is 2-30 normally. If the average number of carbonate repeating units is small, the molecular weight of the polyester resin may be lowered during melting. On the other hand, if it is too large, the melt viscosity of the polycarbonate becomes high, causing a dispersion failure in the molded product, which may deteriorate the appearance of the molded product, particularly the glossiness. Therefore, the average number of repeating units is preferably 3 to 15, particularly 3 to 10.

  It is preferable that content of a polycarbonate (D) is 0.1-5 mass parts with respect to 100 mass parts of thermoplastic polyester resins (A). When the content of the polycarbonate (D) is less than 0.1 parts by mass, the dispersibility of brominated polystyrene tends to be reduced, and when it exceeds 5 parts by mass, mechanical properties and moldability tend to be reduced. . The more preferable content of the polycarbonate (D) is 0.3 to 3 parts by mass, more preferably 0.6 to 2.5 parts by mass, and particularly preferably 1 to 2 parts by mass.

[5.2 Talc (E)]
Talc (E), as is well known, a hydrous magnesium silicate having a layered structure, the chemical formula is typically expressed in _{4SiO 2 · 3MgO · H 2 O} , typically a SiO ₂ 58 to 66 wt% the MgO 28 to 35 wt%, contains of _{H 2} O to about 5 wt%. As other minor components, Fe ₂ O ₃ is 0.03 to 1.2% by mass, Al ₂ O ₃ is 0.05 to 1.5% by mass, CaO is 0.05 to 1.2% by mass, and K ₂ O is Generally, it contains 0.2% by mass or less, Na ₂ O contains 0.2% by mass or less, and the like.

  As the talc (E), those having an average particle diameter of 0.1 to 10 μm are preferable, and 0.3 to 8 μm, particularly 0.7 to 5 μm are more preferable. When the average particle diameter is 0.1 μm or more, the thermal stability of the polyester resin composition tends to be further improved, and when the average particle diameter is less than 10 μm, the appearance and rigidity of the molded article of the polyester resin composition are improved. It tends to improve. The average particle diameter of talc (E) can be determined by a laser diffraction method.

  Moreover, it is preferable that talc (E) is surface-treated in order to improve affinity with a thermoplastic polyester resin (A). Specific examples of the surface treatment agent include alcohols such as trimethylolethane, trimethylolpropane, and pentaerythritol, alkanolamines such as triethylamine, organosilicone compounds such as organopolysiloxane, higher fatty acids such as stearic acid, Fatty acid metal salts such as calcium stearate and magnesium stearate, polyethylene wax, hydrocarbon lubricants such as liquid paraffin, basic amino acids such as lysine and arginine, polyglycerin and their derivatives, silane coupling agents, titanate couplings And at least one selected from coupling agents such as an agent and an aluminum-based coupling agent.

The content of talc (E) is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A). When the content of talc (E) is less than 0.1 parts by mass, the dispersibility of brominated polystyrene tends to decrease, and when it exceeds 5 parts by mass, mechanical strength and toughness tend to decrease. The more preferable content of talc (E) is 0.3 to 4 parts by mass, further preferably 0.4 to 3 parts by mass, and particularly preferably 0.5 to 2.5 parts by mass.
In addition, when using together with talc (E) and a polycarbonate (D), it is preferable to mix | blend 0.1-5 mass parts with respect to 100 mass parts of thermoplastic polyester resins (A), respectively, but talc (E) And the total amount of polycarbonate (D) is preferably 0.5 to 6 parts by mass, more preferably 1 to 4 parts by mass, with respect to 100 parts by mass of the thermoplastic polyester resin (A). It is especially preferable to set it as 3-3.5 mass parts.

[6. Titanium oxide (F)]
The polyester resin composition of the present invention preferably contains titanium oxide (F).
Titanium oxide (F) functions to improve the whiteness and print contrast of the molded product. The production method, crystal form, average particle size, and the like of titanium oxide used for the titanium oxide-based additive are not particularly limited.

  The crystal form of titanium oxide includes a rutile type and an anatase type, but a rutile type crystal form is preferred from the viewpoint of light resistance. The average particle diameter of titanium oxide (F) is usually 0.1 to 0.7 μm, preferably 0.1 to 0.4 μm. The average particle diameter of titanium oxide can be measured by a laser diffraction method.

  In addition, it is also preferable to surface-treat titanium oxide (F) with surface treating agents, such as an alumina type surface treating agent, a silicic acid hydrate, and an organosiloxane type. As the organosiloxane-based surface treatment agent, a polyorganohydrogensiloxane compound is preferable. Alumina hydrate is preferably used as the alumina-based surface treatment agent. By applying such a surface treatment, the thermal stability can be improved, and the uniform dispersibility in the resin composition and the stability of the dispersed state tend to be improved.

  There are (1) a wet method and (2) a dry method as a surface treatment method using a surface treatment agent for titanium oxide. The wet method is a method in which titanium oxide is added to a mixture of a surface treatment agent and a solvent, and after stirring, the solvent is removed, followed by heat treatment at 100 to 300 ° C. Examples of the dry method include a method of mixing titanium oxide and a surface treatment agent with a Henschel mixer or the like, a method of spraying and adhering an organic solution of the surface treatment agent to titanium oxide, and a heat treatment at 100 to 300 ° C. The amount of the surface treatment agent is not particularly limited, but is usually in the range of 1 to 5% by mass with respect to titanium oxide, considering the reflectivity of titanium oxide and the moldability of the resin composition.

  The preferable content of titanium oxide (F) is in the range of 0.1 to 20 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A). When the blending amount of titanium oxide (F) is less than 0.1 parts by mass, the reflectance of the molded product obtained from the resin composition tends to be insufficient, and when it exceeds 20 parts by mass, the impact resistance of the resin composition Tends to be insufficient. The more preferable amount of titanium oxide (F) is 0.3 parts by mass or more, particularly preferably 0.5 parts by mass or more, more preferably 18 parts by mass or less, with respect to 100 parts by mass of the polyester resin (A). Especially preferably, it is 15 mass parts or less. In addition, the mass of titanium oxide (F) means the total mass including these treatment agents when surface treatment is performed with a surface treatment agent such as alumina hydrate, silicic acid hydrate, or organosiloxane. .

[7. Glass fiber (G)]
The polyester resin composition of the present invention can contain glass fibers (G) to improve its mechanical properties. As the glass fiber (G), any conventional fiber can be used.
The average fiber diameter of the glass fiber (G) is not particularly limited, but is preferably selected in the range of, for example, 1 to 100 μm, more preferably 2 to 50 μm, still more preferably 3 to 30 μm, and particularly preferably 5 to 20 μm. Glass fibers having an average fiber diameter of less than 1 μm are not easy to produce and may increase costs, whereas if they exceed 100 μm, the tensile strength of the glass fibers may decrease.
Moreover, although the average fiber length of glass fiber (G) is not specifically limited, For example, it is preferable to select in the range of 0.1-20 mm, and it is more preferable that it is 0.3-5 mm. If the average fiber length is less than 0.1 mm, the reinforcing effect may not be sufficiently exhibited, and if it exceeds 20 mm, it may be difficult to mold the resulting polyester resin composition.

  It is preferable to use the glass fiber (G) that has been surface-treated with a surface treatment agent such as a coupling agent. Glass fibers to which a surface treatment agent is attached are preferred because they tend to be excellent in durability, heat and humidity resistance, hydrolysis resistance, and heat shock resistance.

As the surface treatment agent, any conventionally known one can be used. Specifically, for example, silane coupling agents such as amino silane, epoxy silane, allyl silane, and vinyl silane are preferable.
Among these, aminosilane-based surface treatment agents are preferable, and specifically, for example, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ- (2-aminoethyl) aminopropyltrimethoxysilane are preferable. Take as an example.

Moreover, as a surface treating agent, epoxy resins, such as a novolac type, a bisphenol A type epoxy resin, etc. are mentioned preferably. Among these, a novolac type epoxy resin is more preferable.
The silane-based surface treatment agent and the epoxy resin may be used alone or in combination, and it is also preferable to use both in combination.

  In this invention, it is preferable that glass fiber (G) contains 10-100 mass parts with respect to 100 mass parts of thermoplastic polyester resins (A), especially 15-80 mass parts.

[8. Anti-dripping agent (H)]
It is also preferable for the polyester resin composition of the present invention to contain an anti-dripping agent (H). As the anti-drip agent, polytetrafluoroethylene (PTFE) is preferable, has a fibril-forming ability, easily disperses in the resin composition, and shows a tendency to form a fibrous material by bonding the resins together. More preferred. Specific examples of polytetrafluoroethylene include, for example, trade names “Teflon 6J” or “Teflon 30J” commercially available from Mitsui DuPont Fluorochemical Co., Ltd., trade names “Polyflon” marketed from Daikin Industries, Ltd. Or “Fluon”, a trade name commercially available from Asahi Glass Co., Ltd.
The content ratio of the dripping inhibitor is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A). If the anti-dripping agent is less than 0.1 parts by mass, the flame retardancy tends to be insufficient, and if it exceeds 5 parts by mass, aggregates are likely to be generated and the appearance tends to deteriorate. The content ratio of the anti-dripping agent is more preferably 0.3 to 3.5 parts by mass, and still more preferably 0.5 to 2.5 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A). It is.

[9. Carbon black (I)]
The polyester resin composition of the present invention can contain carbon black (I) to improve printability during laser marking. Any commonly used carbon black can be used, and in general, it may be appropriately selected from carbon blacks used for coloring resin compositions.
The average primary particle size of carbon black is preferably 10 nm or more, more preferably 13 nm or more, and preferably 100 nm or less, more preferably 50 nm or less. Further, DBP oil absorption of carbon black is preferably 30 cm ^3/100 g or more, more preferably 45cm ^3/100 g or more, and preferably 500 cm ^3/100 g or less, and more preferably not more than 130 cm ^3/100 g. In addition, the average primary particle diameter of carbon black can be calculated | required by the arithmetic average diameter calculated | required by observing with an electron microscope. The DBP oil absorption can be measured by the amount of dibutyl phthalate (DBP) absorbed by 100 g of carbon black (based on JIS K6221).

Carbon black is classified into furnace black, channel black, thermal black, etc. depending on the production method, and acetylene black, oil black, gas black, etc. depending on the raw material, and any of these can be used. Also, ketjen black, which is a highly conductive carbon black, can be used. Of these, furnace black is preferred from the viewpoints of dispersibility, colorability of the resin composition, workability (economic efficiency), and the like.
In the present invention, the carbon black is preferably contained in an amount of 0.0001 to 0.1 parts by mass, particularly 0.0005 to 0.01 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A). When the content is less than 0.0001 part by mass, the laser marking property tends to be lowered.

[10. Stabilizer (J)]
It is preferable that the polyester resin composition of the present invention further contains a stabilizer (J) in that it has effects of improving thermal stability and preventing deterioration of mechanical strength, transparency and hue. As the stabilizer, a phosphorus stabilizer and a phenol stabilizer are preferable.

  Examples of the phosphorus-based stabilizer include phosphorous acid, phosphoric acid, phosphite ester, and phosphate ester. Among them, organic phosphate compounds, organic phosphite compounds, and organic phosphonite compounds are preferable.

The organic phosphate compound is preferably the following general formula:
(R ¹ O) _3-n P (═O) OH _n
(In the formula, R ¹ is an alkyl group or an aryl group, and may be the same or different. N represents an integer of 0 to 2.)
It is a compound represented by these. More preferably, R ¹ is a long-chain alkyl acid phosphate compound having 8 to 30 carbon atoms. Specific examples of the alkyl group having 8 to 30 carbon atoms include octyl group, 2-ethylhexyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group, A hexadecyl group, an octadecyl group, an eicosyl group, a triacontyl group, etc. are mentioned.

Examples of the long-chain alkyl acid phosphate include octyl acid phosphate, 2-ethylhexyl acid phosphate, decyl acid phosphate, lauryl acid phosphate, stearyl acid phosphate, oleyl acid phosphate, behenyl acid phosphate, phenyl acid phosphate, nonyl phenyl cyclo acid phosphate Acid phosphate, phenoxyethyl acid phosphate, alkoxy polyethylene glycol acid phosphate, bisphenol A acid phosphate, dimethyl acid phosphate, diethyl acid phosphate, dipropyl acid phosphate, diisopropyl acid phosphate, dibutyl acid phosphate, dioctyl Le acid phosphate, di-2-ethylhexyl acid phosphate, dioctyl acid phosphate, dilauryl acid phosphate, distearyl acid phosphate, diphenyl acid phosphate, and a bis-nonylphenyl acid phosphate, or the like.
Among these, octadecyl acid phosphate is preferable, and this is marketed under the trade name “ADEKA STAB AX-71” of ADEKA.

As the organic phosphite compound, preferably, the following general formula:
^{R 2 O-P (OR 3} ) (OR 4)
Wherein R ² , R ³ and R ⁴ are each a hydrogen atom, an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms, and at least one of R ² , R ³ and R ⁴ One is an aryl group having 6 to 30 carbon atoms.)
The compound represented by these is mentioned.

  Examples of the organic phosphite compound include triphenyl phosphite, tris (nonylphenyl) phosphite, dilauryl hydrogen phosphite, triethyl phosphite, tridecyl phosphite, tris (2-ethylhexyl) phosphite, and tris (tridecyl). ) Phosphite, tristearyl phosphite, diphenyl monodecyl phosphite, monophenyl didecyl phosphite, diphenyl mono (tridecyl) phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite Hydrogenated bisphenol A phenol phosphite polymer, diphenyl hydrogen phosphite, 4,4′-butylidene-bis (3-methyl-6-t rt-butylphenyldi (tridecyl) phosphite), tetra (tridecyl) 4,4′-isopropylidenediphenyldiphosphite, bis (tridecyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, di Lauryl pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tris (4-tert-butylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, hydrogenated bisphenol A pentaerythritol phosphite Phytopolymer, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite Phosphite, 2,2'-methylenebis (4,6-di -tert- butylphenyl) octyl phosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite and the like.

The organic phosphonite compound is preferably the following general formula:
R ⁵ -P (OR ⁶ ) (OR ⁷ )
(Wherein R ⁵ , R ⁶ and R ⁷ are each a hydrogen atom, an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms, and at least one of R ⁵ , R ⁶ and R ⁷ ) One is an aryl group having 6 to 30 carbon atoms.)
The compound represented by these is mentioned.

  Examples of the organic phosphonite compound include tetrakis (2,4-di-iso-propylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,4-di-n-butylphenyl) -4,4′-biphenyl. Range phosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,3'-biphenylene diphospho Knight, tetrakis (2,4-di-tert-butylphenyl) -3,3'-biphenylenediphosphonite, tetrakis (2,6-di-iso-propylphenyl) -4,4'-biphenylenediphosphonite, Tetrakis (2,6-di-n-butylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2, -Di-tert-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-di-tert-butylphenyl) -4,3'-biphenylenediphosphonite, and tetrakis (2,6- And di-tert-butylphenyl) -3,3′-biphenylenediphosphonite.

One type of phosphorous stabilizer may be contained, or two or more types may be contained in any combination and ratio.
As described above, octadecyl acid phosphate that exhibits excellent compatibility and dramatically improves elongation and thin-wall toughness is particularly preferable as the phosphorus stabilizer.

  Examples of the phenol-based stabilizer include pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-tert-butyl-4) -Hydroxyphenyl) propionate, thiodiethylenebis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), pentaerythritol tetrakis (3- (3,5-di-neopentyl-4-hydroxyphenyl) ) Propionate) and the like. Among these, pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate is preferred.

  It is preferable that content of a stabilizer (J) is 0.001-1 mass part with respect to 100 mass parts of thermoplastic polyester resins (A). When the content of the stabilizer is less than 0.001 part by mass, it is difficult to expect an improvement in the thermal stability and compatibility of the resin composition, and a decrease in molecular weight and a deterioration in hue during molding are likely to occur. When it exceeds, it will become excess amount and there exists a tendency for generation | occurrence | production of silver and a hue deterioration to occur further easily. The content of the phosphorus stabilizer is more preferably 0.001 to 0.7 parts by mass, and still more preferably 0.005 to 0.5 parts by mass.

[11. Release agent (K)]
The polyester resin composition of the present invention preferably further contains a release agent (K). As the mold release agent, known mold release agents usually used for polyester resins can be used. Among them, polyolefin compounds, fatty acid ester compounds, and silicone systems are particularly difficult in that they do not hinder metal film adhesion. One or more mold release agents selected from compounds are preferred.

  Examples of the polyolefin compound include compounds selected from paraffin wax and polyethylene wax. Among them, those having a mass average molecular weight of 700 to 10,000, more preferably 900 to 8,000 are preferable.

  Examples of the fatty acid ester compounds include fatty acid esters such as glycerin fatty acid esters and sorbitan fatty acid esters, and partially saponified products thereof. Among them, the fatty acid ester compounds are composed of fatty acids having 11 to 28 carbon atoms, preferably 17 to 21 carbon atoms. Preferred are mono- or di-fatty acid esters. Specifically, glycerol monostearate, glycerol monobehenate, glycerol dibehenate, glycerol-12-hydroxy monostearate, sorbitan monobehenate, etc. are mentioned.

  Moreover, as a silicone type compound, the compound modified | denatured from points, such as compatibility with a polyester resin, is preferable. Examples of the modified silicone oil include silicone oil in which an organic group is introduced into the side chain of polysiloxane, silicone oil in which an organic group is introduced into both ends and / or one end of polysiloxane, and the like. Examples of the organic group to be introduced include an epoxy group, an amino group, a carboxyl group, a carbinol group, a methacryl group, a mercapto group, and a phenol group, and preferably an epoxy group. As the modified silicone oil, a silicone oil in which an epoxy group is introduced into the side chain of polysiloxane is particularly preferable.

  It is preferable that content of a mold release agent (K) is 0.05-2 mass parts with respect to 100 mass parts of thermoplastic polyester resins (A). If the amount is less than 0.05 parts by mass, the surface property tends to be lowered due to defective mold release at the time of melt molding, and the laser marking property may be lowered. On the other hand, when it exceeds 2 parts by mass, the kneading workability of the resin composition is lowered, and the surface of the molded product may be clouded. The content of the release agent is more preferably 0.07 to 1.5 parts by mass, still more preferably 0.1 to 1.0 parts by mass.

[12. Other ingredients]
The polyester resin composition of the present invention may further contain various additives as long as the effects of the present invention are not impaired. Examples of such additives include ultraviolet absorbers, dyes and pigments, fluorescent whitening agents, antistatic agents, antifogging agents, lubricants, antiblocking agents, fluidity improvers, plasticizers, dispersants, antibacterial agents, and the like. It is done.

  Moreover, the polyester resin composition in this invention can contain thermoplastic resins other than a thermoplastic polyester resin (A) in the range which does not impair the effect of this invention. Specific examples of other thermoplastic resins include polyacetal resins, polyamide resins, polyphenylene oxide resins, polystyrene resins, polyphenylene sulfide ethylene resins, polysulfone resins, polyether sulfone resins, polyetherimide resins, polyether ketones. Examples thereof include resins and polyolefin resins.

[13. Method for producing resin composition]
As a manufacturing method of the polyester resin composition of this invention, it can carry out in accordance with the conventional method of resin composition preparation. Usually, the components and various additives added as desired are mixed together and then melt-kneaded in a single-screw or twin-screw extruder. Moreover, it is also possible to prepare the resin composition of the present invention by mixing each component in advance or by mixing only a part of the components in advance and supplying them to an extruder using a feeder and melt-kneading them. Furthermore, a master batch is prepared by melting and kneading a part of a thermoplastic polyester resin and a part of other components, and then melt-kneading the remaining polyester resin and other ingredients. May be.
In addition, when using fibrous things, such as glass fiber, it is also preferable to supply from the side feeder in the middle of the cylinder of an extruder.

  The heating temperature at the time of melt kneading can be appropriately selected from the range of usually 220 to 300 ° C. If the temperature is too high, decomposition gas is likely to be generated, which may cause opacity. Therefore, it is desirable to select a screw configuration in consideration of shear heat generation. In order to suppress decomposition during kneading or molding in the subsequent process, it is desirable to use an antioxidant or a heat stabilizer.

[14. Molded body]
The polyester resin composition of the present invention is usually formed into an arbitrary shape and used as a molded body. There is no restriction | limiting in the shape of a molded object, a pattern, a color, a dimension, etc., What is necessary is just to set arbitrarily according to the use of the molded object.
The manufacturing method of a molded object is not specifically limited, The molding method generally employ | adopted about the polyester resin composition can be employ | adopted arbitrarily. For example, injection molding method, ultra-high speed injection molding method, injection compression molding method, two-color molding method, hollow molding method such as gas assist, molding method using heat insulating mold, rapid heating mold were used. Molding method, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating) molding method, extrusion molding method, sheet molding method, thermoforming method, rotational molding method, laminate molding method, press molding method, blow molding Examples include molding methods. In the present invention, it is preferable to adopt an injection molding method from the viewpoint of versatility.

[15. Laser marking]
The obtained molded body can be easily marked with a laser, and letters, labels, barcodes, QR codes, figures, patterns, etc. are applied by laser marking.
Laser marking methods are known and various methods can be applied.
The laser beam used in the laser marking method is preferably one having a laser oscillation wavelength of 532 to 1,064 nm. Specifically, in an application for color printing on a resin, a YAG wavelength (1,064 nm) laser marker is generally used. Neodymium modified yttrium-aluminum-garnet (YAG), or neodymium modified yttrium-vanadium tetroxide (Nd: YVO ₄ ), etc. A laser marker using a pulse laser by a Q switch device can also be used. In addition, it is also possible to use a laser marker of a fiber type (a type in which a plurality of laser diodes (LDs) are used in a fiber into which yttrium is injected at a low output to generate and amplify laser light) which is becoming mainstream in recent years. it can.

  As the laser marker, the laser beam may be either single mode or multi-mode, and the laser beam can be used not only with a narrow beam diameter of 20 to 40 μm but also with a wide beam diameter of 80 to 100 μm. However, in the single mode, the beam diameter of 20 to 40 μm is preferable because marking can be performed with good contrast.

  A molded article to be subjected to laser marking using the polyester resin composition of the present invention is particularly suitable for, for example, a casing of an electric / electronic device, a base of a lighting device, an element substrate, a casing, or the like.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not construed as being limited to the following examples.
In the following description, “parts” means “parts by mass” based on mass standards unless otherwise specified.
In the following Examples and Comparative Examples, the components used are as shown in Table 1 below.

(Examples 1 to 23, Comparative Examples 1 to 4)
Each component other than the glass fibers described in Tables 2 and 3 below is blended so as to have the blending ratio (parts by mass) described in Tables 2 and 3, and using a twin screw extruder (screw diameter 35 mm), barrel Extrusion was performed at a preset temperature of 250 ° C. and a rotation speed of 200 rpm, and glass fibers were supplied by a side feed method to produce pellets of the resin composition. Using the obtained pellets, an evaluation test piece described below was injection molded at a cylinder temperature of 255 ° C. using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., Nestal SG75-SYCAP-M3A). The number of aggregates in the product and the light resistance of the mark were evaluated.
In molding, the resin composition pellets were dried at 120 ° C. for 6 to 8 hours until immediately before.

The evaluation method is as follows.
(1) Laser marking property:
As a test piece for evaluation, a disk-shaped molded product having a diameter of 100 mm × 2 mm was used. Using “Laser Marker LP-Z130” manufactured by Sunx, the laser oscillation method is fiber, laser power: 50, printing pulse cycle: 50 μs, line width: 0.07 mm, filling interval: 0.035 mm, number of overprinting : Laser marking was performed on the disk-shaped molded product so as to fill a 20 × 20 mm square under the conditions of one time. In the laser marking, the scanning speed was 3,000 mm / sec and 5,000 mm / sec.

Next, using a spectrocolorimetric color difference meter (“CM-3600d” manufactured by Konica Minolta, Inc.), the color difference (ΔE ^* ) between the laser irradiated portion (laser marking portion) and the non-irradiated portion was evaluated by the following equation. It can be said that the greater the ΔE ^* between the laser irradiated portion and the non-irradiated portion, the higher the contrast and the better the laser marking property.
ΔE ^* = ((ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ) ^1/2

(2) Number of aggregates:
A combustion test piece (UL94 standard) having a thickness of 0.3 mm was injection molded, and the number of aggregates in the test piece was visually evaluated. It can be said that the smaller the number of aggregates, the better the appearance of the molded product.

(3) Light resistance of the mark As the test piece for evaluation, a disk-shaped molded product having a diameter of 100 mm × 2 mm was used. Using “Laser Marker LP-Z130” manufactured by SUNX, the laser oscillation method is fiber type, laser power: 30, printing pulse cycle: 50 μs, line width: 0.07 mm, filling interval: 0.035 mm, number of overprinting The QR code was laser-marked on the molded product under the conditions of: 1 time, scan speed: 300 mm / sec, printing direction: one direction, QR code size: 8.12 mm × 8.12 mm, QR code data: MEP.
The obtained test piece was irradiated with a xenon arc weather tester (wavelength: 340 nm, irradiation energy: 1200 kJ / m ² ) for 300 hours under conditions of a black panel temperature of 83 ° C. and no rain. Subsequently, the QR code marked on the test piece after 300 hours of irradiation was read using a mobile phone (“Model: 944SH (CCD camera: 8.0 megapixel barcode reader) manufactured by Softbank)”. The mark that was able to read the QR code was marked as ◯, and the mark that was not possible as x, and the light resistance of the mark was evaluated.

  The above evaluation results are shown in Tables 2 to 3 below.

  From Tables 2 to 3, it can be seen that the polyester resin composition of the present invention is excellent in printability by laser marking and also excellent in light resistance of the mark. On the other hand, it can be confirmed that the resin composition of the comparative example is inferior in the laser marking property or the light resistance of the mark, and does not satisfy the effect of the present invention.

  The polyester resin composition for laser marking of the present invention is excellent in printability by laser marking, and is also excellent in light resistance of the marked mark. Therefore, since the polyester resin composition of the present invention can be suitably applied to a molded product on which printing or the like is performed, industrial utility is very high.

Claims (11)

0.1 of the thermoplastic polyester resin (A) 100 parts by mass of 5 to 30 parts by mass of brominated polystyrene (B), A Nchimon compound (C) 1 to 20 parts by weight, and, polycarbonate (D) A polyester resin composition for laser marking, comprising 5 parts by mass . Further, with respect to the thermoplastic polyester resin (A) 100 parts by mass of, for laser marking polyester resin composition according to claim 1, characterized in that it contains 0.1 to 5 parts by mass of talc (E). Furthermore, 0.1-20 mass parts of titanium oxide (F) is contained with respect to 100 mass parts of thermoplastic polyester resin (A), The polyester resin composition for laser markings of Claim 1 or 2 characterized by the above-mentioned. object. Furthermore, 10-100 mass parts of glass fibers (G) are contained with respect to 100 mass parts of thermoplastic polyester resin (A), The polyester resin for laser markings in any one of Claims 1-3 characterized by the above-mentioned. Composition. Furthermore, 0.1-5 mass parts of anti-dripping agents (H) are contained with respect to 100 mass parts of thermoplastic polyester resin (A), The laser marking in any one of Claims 1-4 characterized by the above-mentioned. Polyester resin composition. The polyester resin composition for laser marking according to any one of claims 1 to 5, wherein the antimony compound (C) is antimony trioxide. The polyester resin composition for laser marking according to any one of claims 1 to 6, wherein the polycarbonate (D) is a brominated polycarbonate. The polyester resin composition for laser marking according to any one of claims 1 to 7, wherein the main component of the thermoplastic polyester resin (A) is polybutylene terephthalate. A molded article formed by molding the polyester resin composition for laser marking according to claim 1. The molded body according to claim 9, which is a casing of an electric / electronic device, or a base, an element substrate, or a casing of a lighting device. The molded body according to claim 9 or 10, wherein the surface is laser-marked.