JP2021130278A - Polyamide resin composition for laser marking, molding, and laser marking method - Google Patents

Abstract

To provide a polyamide resin composition for laser marking which is excellent in laser marking property and surface glossiness when being formed into a molding, and a molding using the polyamide resin composition for laser marking and a laser marking method.SOLUTION: A polyamide resin composition for laser marking contains (A) a polyamide resin, (B) carbon black, and (C) nigrosine. A molding is obtained by molding the polyamide resin composition for laser marking. A laser marking method performs printing on the molding obtained by molding the polyamide resin composition for laser marking by irradiation with a laser beam.SELECTED DRAWING: None

Description

The present invention relates to a polyamide resin composition for laser marking, a molded product, and a laser marking method.

Polyamide resins are widely used in parts such as automobiles, electric and electronic products because they are excellent in mechanical properties, thermal properties and oil resistance. In particular, reinforced polyamide resin, which is a mixture of polyamide resin and glass fiber, greatly improves mechanical properties, heat resistance, chemical resistance, etc. Therefore, from the viewpoint of weight reduction and rationalization of the process, parts that were conventionally made of metal. Can also be made of reinforced polyamide resin, and is suitably used for automobile parts and the like. In order to satisfy customer requirements, these molded products such as electronic device parts and automobile parts are required to be thinner, smaller, and lighter from the viewpoint of design and reliability, and have mechanical properties. The demand for improvement is increasing.

On the other hand, at present, product labeling and marking are indispensable in almost all fields of industry, and the content written on the label or mark is also the date of manufacture, effective date of use, barcode, company logo, serial number. Etc., it is complicated and diverse. These labels or marks have been conventionally attached mainly by a method such as printing, embossing, stamping, or labeling.
Meanwhile, the importance of laser marking on plastics, which can be labeled or marked freely and non-contactly very quickly using a laser, is increasing. This is because when graphic marking is performed on plastic, specifically, when a barcode is applied to an uneven surface, marking can be easily performed at a high speed regardless of the unevenness of the surface. Moreover, since the inscription is engraved on the plastic article itself, it has the advantage of being durable and resistant to wear.

The thermoplastic resin composition for laser marking includes a halogen-containing organic compound and an antimony compound in a ratio of 0.1 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the polyamide resin. Is known (see, for example, Patent Document 1). When the molded product obtained by molding the polyamide resin composition is laser-marked by laser irradiation, the marking color tone becomes darker than the color tone of the surface of the polyamide resin molded product in the non-laser-irradiated portion.
Further, a polyamide resin composition for black laser marking capable of clear black laser marking and excellent in toughness and rigidity is known (see, for example, Patent Document 2).
Further, there is known a composition capable of obtaining a clear chromatic or white mark with high sensitivity and high visibility by irradiating a molded product having a black or dark background color with a laser beam (for example). , Patent Document 3 and Patent Document 4).

JP-A-2007-98939 Japanese Unexamined Patent Publication No. 2007-1504068 Japanese Unexamined Patent Publication No. 8-127175 Japanese Unexamined Patent Publication No. 8-127670

Laser marking is performed by irradiating the surface of a molded product with a laser beam. At that time, the irradiated portion is locally overheated, and the additives and the resin on the resin surface layer portion undergo thermal changes such as dissolution, vaporization, and carbonization, so that marking can be obtained. Therefore, in the resin compositions for laser marking disclosed in Patent Documents 1 and 2, the obtained markings are concavely etched or charred to a dark brown color. The marking characters thus obtained have insufficient contrast with black or dark fabric colors and are difficult to identify, and may be inferior to printed characters.
Further, the resin composition for laser marking disclosed in Patent Document 3 is used for chromatic color-developing laser marking such as red, blue, and yellow. Therefore, although clear marking can be obtained, it is difficult to obtain white marking.
Further, white marking can be obtained by using the resin composition for laser marking disclosed in Patent Document 4. However, yellowing may occur due to thermal deterioration of the thermoplastic resin, and the white marking portion may become yellowish or reddish as compared with printing.

The present invention has been made in view of the above circumstances, and is a polyamide resin composition for laser marking, which is excellent in laser marking property and surface glossiness when formed into a molded product, and the polyamide resin composition for laser marking. The molded article and the laser marking method used are provided.

That is, the present invention includes the following aspects.
(1) A polyamide resin composition for laser marking, which contains (A) a polyamide resin, (B) carbon black, and (C) niglocin.
(2) The (B) carbon black of 0.01 parts by mass or more and 1.0 parts by mass or less and 0.01 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the (A) polyamide resin. The polyamide resin composition for laser marking according to (1), which contains (C) niglocin.
(3) The ratio (B) / {(B) + (C)} of the mass of the (B) carbon black to the sum of the masses of the (B) carbon black and the (C) niglosin is 0.4 or more. The polyamide resin composition for laser marking according to (1) or (2), which is 0.6 or less.
(4) The polyamide resin (A) is selected from the group consisting of polyamide 6, polyamide 46, polyamide 66, polyamide 6T, polyamide 6I and polyamide MXD6, and a copolymerized polyamide containing at least one of these as a constituent component. The polyamide resin composition for laser marking according to any one of (1) to (3), which is one or more of the above.
(5) The (D) glass fiber further contains (D) glass fiber, and the (D) glass fiber is an unsaturated vinyl excluding the carboxylic acid anhydride-containing unsaturated vinyl monomer and the carboxylic acid anhydride-containing unsaturated vinyl monomer. The polyamide resin composition for laser marking according to any one of (1) to (4), which is treated with a sizing agent containing a monomer and a copolymer containing the monomer as a constituent unit.
(6) A molded product obtained by molding the polyamide resin composition for laser marking according to any one of (1) to (5).
(7) A laser marking method in which a molded body obtained by molding the polyamide resin composition for laser marking according to any one of (1) to (5) is irradiated with a laser and printed.

According to the polyamide resin composition for laser marking of the above aspect, it is possible to provide a polyamide resin composition for laser marking which is excellent in laser marking property and surface glossiness when formed into a molded product.

Hereinafter, embodiments for carrying out the present invention (hereinafter, abbreviated as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist thereof.

≪Polyamide resin composition for laser marking≫
The polyamide resin composition for laser marking of the present embodiment (hereinafter, may be simply referred to as "polyamide resin composition") contains (A) polyamide resin, (B) carbon black, and (C) niglocin. do.

In the polyamide resin composition of the present embodiment, when irradiated with laser light, (B) carbon black and (C) niglosin absorb the laser light to generate heat, and the surrounding (A) polyamide resin and (C) ) Niglosin itself can be thermally decomposed and foamed to give a clear white marking to the black or brown molded body. Therefore, by using the polyamide resin composition of the present embodiment, a molded product having excellent laser marking properties can be obtained. Further, since the polyamide resin composition of the present embodiment contains (B) carbon black and (C) niglocin, even when an inorganic filler such as (D) glass fiber is contained, the inorganic filler is damaged. A molded product in which a decrease in strength due to (breaking) is suppressed can be obtained. Further, the polyamide resin composition of the present embodiment contains (C) niglocin, which can delay the crystallization of the composition and improve the smoothness of the surface of the obtained molded product, resulting in good results. As a result, a molded product having excellent surface glossiness can be obtained.

As used herein, the term "laser marking property" means the visibility of a print formed by using a laser on a black or brown molded product. Specifically, the L value / b value, which is an index of the whiteness of printing, is 30 or more, preferably 35 or more, more preferably 37 or more, still more preferably 39 or more, and particularly preferably 39 or more and 60 or less. The molded product is called a molded product having excellent laser marking properties.

Hereinafter, each component of the polyamide resin composition of the present embodiment will be described in detail.

<(A) Polyamide resin>
Generally, the "polyamide resin" means a polymer compound having a -CO-NH- (amide) bond in the main chain.

The polyamide resin (A) is not particularly limited below, but for example, a polyamide obtained by ring-opening polymerization of (Aa) lactam (hereinafter, may be simply abbreviated as "(Aa) polyamide"). (A-b) Condensing polyamide (hereinafter, may be simply abbreviated as "(A-b) polyamide"), (A-c) diamine and dicarboxylic acid obtained by self-condensation of ω-aminocarboxylic acid. (Hereinafter, it may be simply abbreviated as "(Ac) polyamide"), and copolymers thereof. The polyamide resin (A) may be used alone or as a mixture of two or more.

Hereinafter, the raw material of the (A) polyamide resin will be described.

The lactam used as a raw material for the above-mentioned (Aa) polyamide is not particularly limited, and examples thereof include pyrrolidone, caprolactam, undecalactam, and dodecalactam.
The ω-aminocarboxylic acid used as a raw material for the (A-b) polyamide is not particularly limited, and examples thereof include ω-amino fatty acid, which is a ring-opening compound of lactam with water.
The above-mentioned (Aa) polyamide or (Ab) polyamide may be condensed by using two or more kinds of lactam or ω-aminocarboxylic acid in combination.

The diamine (monomer) used as a raw material for the (A-c) polyamide is not particularly limited, but is, for example, a linear aliphatic diamine such as hexamethylenediamine or pentamethylenediamine; 2-methylpentanediamine, Branched chain aliphatic diamines such as 2-ethylhexamethylenediamine; aromatic diamines such as p-phenylenediamine and m-phenylenediamine; alicyclic diamines such as cyclohexanediamine, cyclopentanediamine and cyclooctanediamine. Be done.
The dicarboxylic acid (monomer) used as a raw material for the (A-c) polyamide resin is not particularly limited, and is, for example, an aliphatic dicarboxylic acid such as adipic acid, pimeric acid, and sebacic acid; phthalic acid, isophthalic acid, and the like. Aromatic dicarboxylic acid of the above; alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid and the like can be mentioned.
The diamine and dicarboxylic acid as the above-mentioned monomers may be condensed by one kind alone or in combination of two or more kinds, respectively.

The polyamide resin (A) is not particularly limited, but for example, polyamide 4 (poly α-pyrrolidone), polyamide 6 (polycaproamide), polyamide 11 (polyundecaneamide), polyamide 12 (polydodecaneamide), and polyamide 46. (Polytetramethylene adipamide), Polyamide 56 (Polypentamethylene adipamide), Polyamide 66 (Polyhexamethylene adipamide), Polyamide 610 (Polyhexamethylene sebacamide), Polyamide 612 (Polyhexamethylene dodecamide) ), Polyamide 1010 (Polydecamethylene sebacamide), Polyamide 1012 (Polydecamethylene dodecamide), Polyamide 6T (Polyhexamethylene terephthalamide), Polyamide 9T (Polynonan methylene terephthalamide), Polyamide MXD6 (Polymethaxylylene azi) Pamide) and polyamide 6I (polyhexamethylene isophthalamide), and copolymerized polyamides containing these as constituents can be mentioned.

The copolymerized polyamide is not particularly limited, and examples thereof include a copolymer of polyamide 66 and polyamide 6T, a copolymer of polyamide 66 and polyamide 6I, and a copolymer of polyamide 6T and polyamide 6I.

Among them, the (A) polyamide resin was selected from the group consisting of polyamide 6, polyamide 46, polyamide 66, polyamide 6T, polyamide 6I, and polyamide MXD6, and a copolymerized polyamide containing at least one of these as a constituent component. It is preferably one or more. Further, the (A) polyamide resin is more preferably one or more selected from the group consisting of polyamide 6, polyamide 66, polyamide 6I, and a copolymerized polyamide containing at least one of these as a constituent component, and the polyamide 66. , Or polyamide 6I is more preferred. By using such a polyamide resin (A), the mechanical strength, thermal rigidity, and surface glossiness of the obtained molded product tend to be more excellent.

The terminal group of the polyamide resin generally has an amino group or a carboxy group. Although not particularly limited, (A) the ratio of the amino terminal group amount to the total amount of the amino terminal group amount and the carboxy terminal group amount of the polyamide resin [amino terminal group amount / (amino terminal group amount + carboxy terminal group amount)] is It is preferably 0.2 or more and less than 1.0, more preferably 0.2 or more and 0.8 or less, and further preferably 0.2 or more and 0.6 or less. When the ratio of the amount of terminal groups is within the above range, the color tone and mechanical strength of the molded product obtained from the polyamide resin composition tend to be more excellent.

The amount of amino-terminal groups of the polyamide resin is preferably 10 μmol / g or more and 100 μmol / g or less, more preferably 15 μmol / g or more and 80 μmol / g or less, and further preferably 30 μmol / g or more and 80 μmol / g or less. When the amount of amino-terminal groups is within the above range, the mechanical strength of the polyamide resin composition tends to be more excellent.

Here, as a method for measuring the amount of amino-terminal group and the amount of carboxy-terminal group in the present specification, ¹ H-NMR method and titration method can be mentioned. ^{1 In the 1} H-NMR method, it can be obtained from the integrated value of the characteristic signal corresponding to each terminal group. In the titration method, a method of titrating a phenol solution of a polyamide resin with 0.1N hydrochloric acid for an amino terminal group, a method of titrating a benzyl alcohol solution of a polyamide resin with 0.1N sodium hydroxide for a carboxy terminal group, etc. Can be mentioned.

As a method for adjusting the concentration of the terminal group of the polyamide resin, a known method can be used. The adjusting method is not particularly limited, and examples thereof include a method using a terminal adjusting agent. As a specific example, one or more terminal modifiers selected from the group consisting of monoamine compounds, diamine compounds, monocarboxylic acid compounds, and dicarboxylic acid compounds are added so as to have a predetermined terminal concentration during the polymerization of polyamide. Can be mentioned. The timing of adding the terminal adjusting agent to the solvent is not particularly limited as long as it fulfills its original function as the terminal adjusting agent, and for example, the above-mentioned polyamide raw material may be added to the solvent.

The monoamine compound is not particularly limited, but is, for example, an aliphatic monoamine such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine and dibutylamine. Alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine and naphthylamine can be mentioned. These monoamine compounds may be used alone or in combination of two or more. Of these, butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine or aniline are preferable from the viewpoints of reactivity, boiling point, stability of the sealing end, price and the like.

The diamine compound is not particularly limited, but is, for example, a linear aliphatic diamine such as hexamethylenediamine and pentamethylenediamine; and a branched chain aliphatic diamine such as 2-methylpentanediamine and 2-ethylhexamethylenediamine. Aromatic diamines such as p-phenylenediamine and m-phenylenediamine; alicyclic diamines such as cyclohexanediamine, cyclopentanediamine and cyclooctanediamine can be mentioned. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The monocarboxylic acid compound is not particularly limited, and is, for example, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, capric acid, lauric acid, tridecyl acid, myristyl acid, palmitic acid, stearic acid, pivalic acid, and isobutyl. Alicyclic monocarboxylic acids such as acids; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acids; aromatics such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, phenylacetic acid, etc. Examples include monocarboxylic acid. These monocarboxylic acid compounds may be used alone or in combination of two or more.

The dicarboxylic acid compound is not particularly limited, and is, for example, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladiponic acid, pimeric acid, 2,2-dimethylglutaric acid. , 3,3-Diethylsuccinic acid, azelaic acid, sebacic acid, suberic acid and other aliphatic dicarboxylic acids; 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids; isophthalic acid , 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphenylic acid, diphenylmethane- Examples thereof include aromatic dicarboxylic acids such as 4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, and 4,4'-biphenyldicarboxylic acid. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The viscosity number (VN) of the polyamide resin (VN) measured with 96% (mass fraction) sulfuric acid in accordance with ISO 307 is preferably 40 mL / g or more and 180 mL / g or less, and 45 mL / g or more and 150 mL / g. The following is more preferable, 50 mL / g or more and 145 mL / g or less is further preferable, and 53 mL / g or more and 143 mL / g or less is particularly preferable. When the viscosity number (VN) of the polyamide resin (A) is within the above range, it is more excellent in mechanical strength when formed into a molded product, fluidity during injection molding, and appearance.

The blending amount of the polyamide resin (A) is preferably 29.9% by mass or more and 99.9% by mass or less, and 34.9% by mass or more and 99% by mass, based on 100% by mass of the polyamide resin composition from the viewpoint of fluidity and appearance. It is more preferably 9.9% by mass or less, further preferably 39.9% by mass or more and 99.9% by mass or less, and particularly preferably 49.9% by mass or more and 99.9% by mass or less.

<(B) Carbon black>
In general, "carbon black" has the effect of coloring the fabric color of the molded product into black, and also functions as a laser light absorber when irradiated with laser light. That is, carbon black absorbs laser light to generate heat, and pyrolyzes and foams the thermoplastic resin around it to impart white markings.
Carbon black is classified into furnace black, channel black, thermal black, etc. according to its manufacturing method, and acetylene black, ketjen black, oil black, gas black, etc., depending on the difference in raw materials. Any of these can be used in the polyamide resin composition of the present embodiment.

(B) The average primary particle size of carbon black is preferably 10 nm or more and 40 nm or less, more preferably 10 nm or more and 30 nm or less, and further preferably 10 nm or more and 20 nm or less. (B) When the average primary particle size of carbon black is at least the above lower limit value, the dispersibility in the composition is excellent, while when it is at least the above upper limit value, the strength and rigidity of the molded product are obtained. Can be more expressed.
Here, the average primary particle size is defined as an aggregate magnified image obtained by the procedure described in the ATM D3849 standard (standard test method for carbon black-morphological characterization by electron microscopy), and the unit composition is obtained from this aggregate image. It means the average value calculated by measuring the diameter of 3,000 particles.

As for (B) carbon black, the specific surface area measured by the BET adsorption method is 50 m ² / g or more and 300 m ² / g or less, and the oil absorption measured using dibutylphthalate is 50 mL / 100 g or more and 150 mL / g. Those weighing 100 g or less can be preferably used.

The content of (B) carbon black is preferably 0.01 part by mass or more and 1.0 part by mass or less, and more preferably 0.025 part by mass or more and 0.5 part by mass or less with respect to 100 parts by mass of the polyamide resin composition. It is preferably 0.02 parts by mass or more and 0.5 parts by mass or less. When the content of (B) carbon black is at least the above lower limit value, a clearer contrast can be obtained by generating heat by laser irradiation. On the other hand, when the content of (B) carbon black is not more than the above upper limit value, the amount of laser light energy absorbed does not become excessive, and a clearer contrast can be obtained.

<(C) Nigrosin>
Nigrosin has the effect of coloring the fabric color of the molded product black, and when irradiated with laser light, it absorbs the laser light and generates heat, and the thermoplastic resin around it and nigrocin itself are thermally decomposed and foamed. By letting it give a white marking. That is, niglosin absorbs laser light, generates heat, and foams finely to give a clear white marking.

(C) Niglosin is not particularly limited, but for example, C.I. I. SOLVENT BLACK 5, C.I. I. SOLVENT BLACK 7, C.I. I. Examples of Acid Black 2 include azine-based condensed mixtures such as black triphenylazine oxazine and phenazine azine, which are described in COLORINDEX. Moreover, a part thereof may be denatured. Examples of commercially available niglocin include Nubian Black PA-9801, Nubian Black PA-9800, Nubian Black PA-080 and the like.

The content of niglocin is preferably 0.01 part by mass or more and 1.0 part by mass or less, more preferably 0.025 part by mass or more and 0.5 part by mass or less, and 0.02 part by mass with respect to 100 parts by mass of the polyamide resin composition. 5 parts or more and 0.5 parts by mass or less are preferable. (C) When the content of niglocin is at least the above lower limit value, the yellowness and redness of the marking (printed portion) can be further reduced. On the other hand, when the content of (C) niglocin is not more than the above upper limit value, the bluish tint of the marking can be further suppressed.

In the polyamide resin composition of the present embodiment, carbon black and niglocin are used in combination as the colorant from the viewpoint of improving the balance between the whiteness of the printed portion and the surface glossiness. The total content of these colorants is preferably 0.01 part by mass or more and 1.0 part by mass or less, and more preferably 0.05 part by mass or more and 0.9 part by mass or less with respect to 100 parts by mass of the polyamide resin composition. , 0.1 part by mass or more and 0.9 part by mass or less is more preferable. When the total content of the colorants is within the above range name, the printed portion after laser irradiation can be made clearer white.

In the polyamide resin composition of the present embodiment, the ratio of the mass of (B) carbon black to the sum of the masses of (B) carbon black and (C) niglocin is (B) / {(B) + (C)}. It is preferably 0.2 or more and 0.9 or less, more preferably 0.3 or more and 0.8 or less, and further preferably 0.4 or more and 0.6 or less. When (B) / {(B) + (C)} is equal to or higher than the above lower limit value, the whiteness of the printed portion in the molded product can be improved, while (B) / {(B). When + (C)} is not more than the above upper limit value, the surface glossiness of the molded product can be made more excellent.

<(D) Glass fiber>
In addition to the above-mentioned components (A) to (C), the polyamide resin composition of the present embodiment may further contain (D) glass fiber. By containing the glass fiber (D), a molded product having excellent mechanical strength and rigidity can be obtained.

(D) The glass fiber may have a circular cross section or a flat shape (oval shape, cocoon shape, etc.). From the viewpoint of low warpage, it is preferably flat.

The fiber diameter of the glass fiber (D) when the cross section is circular is preferably 3 μm or more and 30 μm or less, more preferably 9 μm or more and 20 μm or less, and more preferably 12 μm or more because it is excellent in mechanical strength and appearance when formed into a molded product. It is more preferably 19 μm or less.

The average minor axis of the glass fiber (D) when the cross section is flat is preferably 3 μm or more and 15 μm or less, and 4 μm or more and 10 μm or less because it is excellent in mechanical strength, appearance and low warpage when formed into a molded product. More preferably, it is 5 μm or more and 9 μm or less.

Regardless of whether it is circular or flat, the average cross-sectional area of (D) glass fiber is 50 μm ² or more and 350 μm ² or less because it is excellent in mechanical strength and appearance when formed into a molded product. Is preferable, 100 μm ² or more and 300 μm ² or less is more preferable, and 120 μm ² or more and 250 μm ² or less is further preferable. The average cross-sectional area referred to here is a value obtained by taking a photograph using a microscope, measuring the cross-sectional area of 50 randomly selected fibers, and averaging them.

The specific composition of the glass fiber (D) is not limited to the following, but is, for example, an E glass (non-alkali glass) composition, a C glass (alkali-containing glass) composition, and an S glass (tempered glass) composition. , Alkali resistant glass composition and the like. Among these, the E glass composition is preferable from the viewpoint of easy availability.

(D) The glass fiber may be treated with at least one selected from the group consisting of a surface treatment agent and a sizing agent. (D) Since the glass fiber is treated with at least one selected from the group consisting of a surface treatment agent and a sizing agent, it is excellent in processability, particularly defibration. The surface treatment agent and the sizing agent for the glass fiber (D) are not particularly limited, and are, for example, a polyurethane resin, a polycarbodiimide compound, a homopolymer of acrylic acid, and a copolymerization monomer excluding acrylic acid and the acrylic acid. Copolymers, the homopolymers or salts of the copolymers with primary, secondary or tertiary amines, epoxy resins, and carboxylic acid anhydride-containing unsaturated vinyl monomers and the carboxylic acid anhydride-free Examples thereof include copolymers containing unsaturated vinyl monomers other than saturated vinyl monomers. These may be used alone or in combination of two or more.

The polyurethane resin is not particularly limited as long as it is generally used as a surface treatment agent and a sizing agent for (D) glass fibers, and for example, m-xylylene diisocyanate (XDI), 4,4'-methylenebis. Examples thereof include those synthesized from isocyanates such as (cyclohexyl isocyanate) (HMDI) and isophorone diisocyanate (IPDI), and polyester-based and polyether-based diols.

The epoxy resin is not particularly limited, but for example, one having at least two or more glycidyl groups is preferable, and among them, an epoxy resin obtained by reacting bisphenol with epihalohydrin is more preferable. The epoxy equivalent of the epoxy resin is preferably 180 g / molar equivalent or more, and more preferably 450 g / molar equivalent or more and 1900 g / molar equivalent or less. When the epoxy equivalent is within the above range, the focusing property of the glass fiber (D) tends to be further improved.

The weight average molecular weight of the acrylic acid homopolymer is preferably 1,000 or more and 90,000 or less, more preferably 1,000 or more and 25,000 or less, and further preferably 1,000 or more and 25,000 or less. The weight average molecular weight can be measured by a conventional method using GPC.

The monomer constituting the copolymer of acrylic acid and other copolymerizable monomer is not particularly limited, and examples thereof include a monomer having at least one selected from the group consisting of a hydroxyl group and a carboxy group. The monomer having at least one selected from the group consisting of such hydroxyl groups and carboxy groups is not particularly limited, but for example, acrylic acid, maleic acid, methacrylic acid, vinyl acetic acid, crotonic acid, isocrotonic acid, fumaric acid, and the like. One or more selected from the group consisting of itaconic acid, citraconic acid and mesaconic acid can be mentioned (except for acrylic acid alone). Among the above-mentioned monomers, it is preferable to have one or more ester-based monomers.

The primary, secondary and tertiary amines capable of forming a salt with at least one polymer selected from the group consisting of homopolymers and copolymers of acrylic acid are not particularly limited, but are, for example, triethylamine and triethanolamine. Examples include amines and glycines. The degree of neutralization is preferably 20% or more and 90% or less, more preferably 30% or more and 80% or less, from the viewpoint of improving the stability of the mixed solution with other concomitant agents (silane coupling agent, etc.) and reducing the amine odor. It is preferable, and more preferably 40% or more and 60% or less.

The weight average molecular weight of the acrylic acid polymer forming a salt with the primary, secondary and tertiary amines is not particularly limited, but is preferably 3,000 or more and 50,000 or less. When the weight average molecular weight is at least the above lower limit value, the focusing property of the glass fiber tends to be further improved. On the other hand, when the weight average molecular weight is not more than the above upper limit value, the mechanical properties of the resin composition tend to be further improved.

Among them, (D) the surface treatment agent and the sizing agent for the glass fiber are a carboxylic acid anhydride-containing unsaturated vinyl monomer and an unsaturated vinyl monomer excluding the carboxylic acid anhydride-containing unsaturated vinyl monomer. , Is preferably contained. By including such a copolymer, the mechanical properties of the obtained molded product tend to be more excellent.

The carboxylic acid anhydride-containing unsaturated vinyl monomer is not particularly limited, and examples thereof include maleic anhydride, itaconic anhydride, and citraconic anhydride. Of these, maleic anhydride is preferred.

The unsaturated vinyl monomer other than the carboxylic acid anhydride-containing unsaturated vinyl monomer means an unsaturated vinyl monomer different from the carboxylic acid anhydride-containing unsaturated vinyl monomer. Such unsaturated vinyl monomer is not particularly limited, and is, for example, styrene, α-methylstyrene, ethylene, propylene, butadiene, isoprene, chloroprene, 2,3-dichlorobutadiene, 1,3-pentadiene, cyclo. Examples thereof include octadiene, methyl methacrylate, methyl acrylate, ethyl acrylate and ethyl methacrylate. Of these, styrene or butadiene is preferable.

The copolymer of the carboxylic acid anhydride-containing unsaturated vinyl monomer and the unsaturated vinyl monomer excluding the carboxylic acid anhydride-containing unsaturated vinyl monomer is not particularly limited, but is, for example, anhydrous. A copolymer of maleic acid and butadiene, a copolymer of maleic anhydride and ethylene, a copolymer of maleic anhydride and styrene, or a mixture thereof is preferable.

The weight average molecular weight of the copolymer of the carboxylic acid anhydride-containing unsaturated vinyl monomer and the unsaturated vinyl monomer other than the carboxylic acid anhydride-containing unsaturated vinyl monomer is 2,000 or more. Is preferable, and 5,000 or more is more preferable. The weight average molecular weight is preferably 1,000,000 or less, more preferably 500,000 or less. When the weight average molecular weight is within the above range, the fluidity of the resin composition tends to be further improved. The weight average molecular weight in the present specification can be measured by gel permeation chromatography (GPC).

The surface treatment agent for the glass fiber (D) is not particularly limited, but for example, a silane coupling agent can also be used. The silane coupling agent is not particularly limited, but for example, aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane. Classes; mercaptosilanes such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane; epoxysilanes; vinylsilanes. Among these, aminosilanes are preferable. These surface treatment agents may be used alone or in combination of two or more.

(D) It is preferable to use a lubricant when preparing at least one selected from the group consisting of a glass fiber surface treatment agent and a sizing agent. The lubricant is not particularly limited, and for example, any ordinary liquid or solid lubricant material depending on the intended purpose can be used. Such a lubricant is not particularly limited, but for example, animal / plant-based or mineral-based waxes such as carnauba wax and lanolin wax; fatty acid amides, fatty acid esters, fatty acid ethers; aromatic esters, aromatic ethers and the like. Examples of surfactants.

[(D) Method for producing glass fiber]
(D) As the glass fiber, at least one selected from the group consisting of the above-mentioned surface treatment agent and sizing agent is made into a glass fiber by using a known method such as a roller type applicator in a known glass fiber manufacturing process. It is obtained by continuously reacting by drying the fiber strands produced by coating (imparting).

The state of the glass fiber (D) is not particularly limited, but for example, the glass fiber strand may be used as it is as a roving, or may be used as a chopped strand after a further cutting step. The strands may be dried after the cutting step or before the cutting step.

The adhesion amount of at least one selected from the group consisting of the surface treatment agent and the sizing agent is preferably 0.2% by mass or more and 3% by mass or less as the solid content ratio with respect to 100% by mass of (D) glass fiber. It is more preferably 0.2% by mass or more and 2% by mass or less, and further preferably 0.3% by mass or more and 2% by mass or less. When the amount of adhesion of at least one selected from the group consisting of the surface treatment agent and the sizing agent is at least the above lower limit value, the sizing property of the glass fiber tends to be further improved. On the other hand, when the amount of adhesion of at least one selected from the group consisting of the surface treatment agent and the sizing agent is not more than the above upper limit value, the thermal stability of the resin composition tends to be further improved.

As the glass fiber (D), only one type may be used alone, or two or more types having different cross-sectional shapes, average cross-sectional areas, glass compositions, surface treatment agents, sizing agents and the like may be used in combination.

Further, (D), the glass fiber may be used in a roving form, and may be used, for example, in a chopped strand cut to a length of 2 mm or more and 5 mm or less.

(D) The weight average fiber length of the glass fiber length is preferably 100 μm or more and 750 μm or less, more preferably 150 μm or more and 500 μm or less, and further preferably 200 μm or more and 400 μm or less because the mechanical strength and appearance of the molded product are excellent. preferable. For the weight average fiber length, for example, pellets of the polyamide resin composition are heated and incinerated at a temperature equal to or higher than the decomposition temperature of the polyamide resin composition, and the remaining ash is photographed using a microscope to measure the length of the glass fiber. Measure by method. Next, the weight average fiber length is calculated from the measured values obtained by the microscope using the following formula.

Weight average fiber length = sum of squares of glass fiber length / total of glass fiber length

The content of the glass fiber (D) is preferably 1 part by mass or more and 200 parts by mass or less, more preferably 5 parts by mass or more and 150 parts by mass or less, and 30 parts by mass or more and 120 parts by mass or less with respect to 100 parts by mass of the polyamide resin. More preferred.
When the content of the glass fiber (D) is within the above range, the mechanical strength, fluidity and appearance of the molded product tend to be better.

<(E) Other ingredients>
The polyamide resin composition of the present embodiment may further contain (E) and other components, if necessary, in addition to the above components (A) to (C).
(E) Other components are not particularly limited, but are, for example, phenol-based heat stabilizers, phosphorus-based heat stabilizers, amine-based heat stabilizers, sulfur-based heat stabilizers, ultraviolet absorbers, light deterioration inhibitors, and plasticizers. , Lubricants, crystal nucleating agents, mold release agents, flame retardants, coloring agents, dyeing agents, pigments, other thermoplastic resins and the like. Here, since the other components (E) described above have significantly different properties, the preferable content rate of each component varies. Then, a person skilled in the art can easily set the suitable content rate for each of the above-mentioned (E) and other components.

[Manufacturing method of polyamide resin composition for laser marking]
The method for producing the polyamide resin composition of the present embodiment is not particularly limited, but a method of kneading the (A) polyamide resin in a molten state by a single-screw or multi-screw extruder can be used. For example, using a twin-screw extruder equipped with an upstream side supply port and a downstream side supply port, (A) polyamide resin, (B) niglosin, and (C) carbon black are supplied from the upstream side supply port. It is preferable to use a method of supplying (D) glass fibers from the downstream supply port to melt and knead the fibers. Further, when roving of glass fiber is also used, it can be composited by a known method.

≪Molded body≫
The molded product of the present embodiment is formed by molding the above-mentioned polyamide resin composition.

The molded product of this embodiment is excellent in laser marking property and surface gloss property.

The molding method of the molded body is not particularly limited, and examples thereof include injection molding, blow molding, and sheet molding.

The molded body can be used as various parts.
These various parts can be suitably used, for example, for automobiles, machine industry, electric and electronic, industrial materials, industrial materials, and daily / household products.
Among them, since the molded body has an excellent appearance, the air intake manifold, the intercooler inlet, the exhaust pipe cover, the inner bush, the bearing retainer, the engine mount, the engine head cover, the resonator, and the throttle body, the chain cover, the thermostat housing, the outlet pipe, and the radiator tank. , Oil nator, delivery pipe, and other parts of an automobile engine room, and the like.

≪Laser marking method≫
The polyamide resin composition of the present embodiment irradiates a laser beam to develop a color. Examples of the laser beam to be irradiated include gas lasers such as He-Ne laser, Ar laser, CO ₂ laser, and excima laser, _{solid-state laser such as YAG laser and YVO 4} , semiconductor laser, and dye laser. Among these, YAG lasers, solid state lasers such as YVO ₄ laser.

The laser beam of the laser beam to be irradiated may be in single mode or multi-mode. Further, in addition to those having a beam diameter of 20 μm or more and 40 μm or less, a laser beam having a wide beam diameter such as 80 μm or more and 100 μm or less can be used. Among them, a laser beam having a beam diameter of 20 μm or more and 40 μm or less in a single mode is preferable because the contrast between the print coloring portion and the fabric is 3 or more and the contrast is good print quality.

Hereinafter, the present embodiment will be described in more detail with reference to Examples and Comparative Examples, but the present embodiment is not limited to these Examples. First, the measurement method, evaluation method, and raw material used in Examples and Comparative Examples are shown below.

<Ingredients used>
(A) Polyamide resin (A-1) Polyamide 66 (hereinafter, may be abbreviated as "A-1")
VN (sulfuric acid): 141 mL / kg, amino-terminal group: 40 mmol / kg,
Carboxylic acid terminal group: 80 mmol / kg
(A-2) Polyamide 6 (hereinafter, may be abbreviated as "A-2")
VN (sulfuric acid): 114 mL / kg, amino-terminal group: 43 mmol / kg,
Carboxylic acid terminal group: 78 mmol / kg
(A-3) Polyamide 6I (hereinafter, may be abbreviated as "A-3")
VN (sulfuric acid): 53 mL / kg, amino-terminal group: 50 mmol / kg,
Carboxylic acid terminal group: 200 mmol / kg

(B) Carbon black Carbon black with a primary particle size of 27 nm (manufactured by Mitsubishi Chemical Corporation; Mitsubishi Carbon (registered trademark) # 50)

(C) Nigrosin Nubian Black TN-870 (manufactured by Orient Chemical Industries Co., Ltd.)

(D) Inorganic filler Glass fiber (manufactured by Nippon Electric Glass Co., Ltd .; ECS 03T-275H)

<Manufacturing of injection molded plates>
Made by Toshiba Machine Co., Ltd .; Using an IS150E injection molding machine, the injection pressure and speed are appropriately adjusted so that the filling time is about 1.5 seconds at a cylinder temperature of 280 ° C and a mold temperature of 110 ° C or 80 ° C. After adjustment, an injection molded plate having a size of 100 mm × 90 mm × 3 mm was obtained.

<Evaluation method>
[Evaluation 1]
(Laser marking property)
(1) L value / b value Using the obtained injection molded plate, an IR laser (1064 nm) (trade name "MX-Z2050H", manufactured by OMRON Corporation) is used to emit laser light at a laser irradiation rate of 300 mm / sec. Irradiation was performed and the laser marking property was evaluated. In the evaluation, the portion colored by the laser irradiation was measured with a color difference meter, and the value obtained by dividing the L value by the b value was evaluated according to the following evaluation criteria. As the color difference meter, a color difference meter ZE-2000 manufactured by Nippon Denshoku Co., Ltd. was used.

(Evaluation criteria)
L value / b value = -10: Blue to green L value / b value = 5: Yellow to brown L value / b value = 40: White to gray L value / b Value = around 50: White in the printed area L value / b value = 100 or more: White in the printed area to bluish white

(2) Visibility of whiteness Regarding the visibility of whiteness, the portion colored by laser irradiation is visually observed as follows using an injection-molded plate that has been laser-marked by the method described in (1) above. It was evaluated according to the evaluation criteria.

(Evaluation criteria)
⊚: The printed part is white 〇: The printed part is white to gray Δ: The printed part is white to bluish white ×: The printed part is yellow to brown

[Evaluation 2]
(Surface gloss)
The obtained injection-molded plate was measured for 60-degree gloss using a gloss meter (manufactured by HORIBA; IG320) according to JIS-K7150. It was evaluated that the larger the gloss value, the better the glossiness of the surface of the molded product.

[Examples 1 to 17 and Comparative Examples 1 to 2]
(Production of Polyamide Resin Compositions PA-a1 to PA-a17 and PA-b1 to PA-b2)
L / D (extruder cylinder length / extruder cylinder diameter) having an upstream supply port in the first barrel from the upstream side of the extruder and a downstream supply port in the ninth barrel. A twin-screw extruder (ZSK-26MC: manufactured by Coperion Co., Ltd. (Germany)) having 48 barrels and 12 barrels was used. In the twin-screw extruder, the temperature from the upstream supply port to the die was set to 280 ° C., a screw rotation speed of 300 rpm, and a discharge rate of 25 kg / hour. Under such conditions, (A) polyamide resin, (B) carbon black, and (C) niglosin were supplied from the upstream supply port so as to have the composition ratios shown in Tables 1 to 4. For the polyamide resin composition containing the glass fiber (D), the glass fiber was supplied from the downstream supply port in the ninth barrel. Then, these were melt-kneaded to produce pellets of a polyamide resin composition. The pellets of the obtained polyamide resin composition were pre-dried at 120 ° C. for 3 hours.

The measurement results and evaluation results of the physical properties of the pellets of the polyamide resin composition obtained in Examples and Comparative Examples are shown in Tables 1 to 4 below.

From Tables 1 to 4, the polyamide resin compositions PA-a1 to PA-a17 (Examples 1 to 17) containing (A) polyamide resin, (B) carbon black and (C) niglocin were used as molded articles. Both the laser marking property and the surface glossiness were excellent.
Further, in the polyamide resin compositions PA-a1 to PA-a17 (Examples 1 to 17), the smaller the (B) / {(B) + (C)}, the larger the L value / b value tends to be. When (B) / {(B) + (C)} was 0.4 or more and 0.6 or less, the laser marking property of the molded product tended to be superior.
Further, in the polyamide resin compositions PA-a1 to PA-a17 (Examples 1 to 17), the polyamide resin compositions PA-a1 to PA-a12 (Examples 1 to 12) containing no glass fiber (D) are more suitable. There was a tendency for the surface glossiness of the molded product to be superior.

On the other hand, in the polyamide resin compositions PA-b1 to PA-b2 (Comparative Examples 1 and 2) containing no (C) niglosin or (B) carbon black, either the laser marking property or the surface glossiness of the molded product is obtained. Was also inferior.

According to the polyamide resin composition for laser marking of the present embodiment, it is possible to provide a polyamide resin composition for laser marking which is excellent in laser marking property and surface glossiness when formed into a molded product.

Claims (7)

A polyamide resin composition for laser marking, which contains (A) a polyamide resin, (B) carbon black, and (C) niglocin. The (B) carbon black of 0.01 parts by mass or more and 1.0 parts by mass or less and the above (C) of 0.01 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the (A) polyamide resin. The polyamide resin composition for laser marking according to claim 1, which contains niglosin. The ratio (B) / {(B) + (C)} of the mass of the (B) carbon black to the sum of the masses of the (B) carbon black and the (C) niglosin is 0.4 or more and 0.6. The polyamide resin composition for laser marking according to claim 1 or 2, which is as follows. One selected from the group consisting of polyamide 6, polyamide 46, polyamide 66, polyamide 6T, polyamide 6I and polyamide MXD6, and a copolymerized polyamide containing at least one of these as a constituent component. The polyamide resin composition for laser marking according to any one of claims 1 to 3 as described above. (D) Further containing glass fiber
The (D) glass fiber contains a carboxylic acid anhydride-containing unsaturated vinyl monomer and an unsaturated vinyl monomer excluding the carboxylic acid anhydride-containing unsaturated vinyl monomer as a constituent unit. The polyamide resin composition for laser marking according to any one of claims 1 to 4, which has been treated with a sizing agent containing a coalescence. A molded product obtained by molding the polyamide resin composition for laser marking according to any one of claims 1 to 5. A laser marking method for printing by irradiating a molded body obtained by molding the polyamide resin composition for laser marking according to any one of claims 1 to 5 with a laser.