JPH11321093A - Laser marking composition and its article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a colored marking with an excellent contrast not bringing about environmental contamination and having high visibility by incorporating a compound which develops color with a laser beam and a fluorescent dye. SOLUTION: The laser marking composition comprises a compound such as a yellow iron oxide, nickel carbonate, cobalt carbonate, copper oxalate or the like colored by a laser beam, basic pigment such as a naphthalic acid organic pigment, coumarin organic pigment or the like, a basic dye such as methine basic dye, xanthene basic dye or the like such as a Rhodamine 6G, a fluorescent dye such as an inorganic pigment such as a zinc sulfate, zinc silicate, cadmium zinc sulfate, calcium sulfate, strontium sulfate, calcium tangstate, daylight fluorescent pigment or the like. Thus, the composition has excellent contrast for coloring in a clear light brown to brown color by the beam without bringing about an environmental contamination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser marking composition capable of giving a mark with good contrast with the background and high visibility by irradiating a laser beam onto the surface of the formed material.

[0002]

2. Description of the Related Art In recent years, electronic components such as ICs, resistors, capacitors, and inductors, electronic components such as relays, switches, connectors, and printed circuit boards, housings for electric products, automobile parts, machine parts, cables, sheets, and packaging. To the surface of sheets, cards, various containers for foods or pharmaceuticals, caps of containers, labels, etc., manufacturer name, product name,
In marking characters and symbols such as the production date and lot number, a printing method using a marking ink or a marking method using an ink jet has become widespread. However, these methods require a long time in the process from printing to the drying of the ink, difficulty in marking fine parts, maintenance of printing quality, complicated management, high cost, and use of solvents. There is a problem such as environmental pollution due to the above, and its rationalization is desired. In recent years, in order to streamline the marking, a laser marking method of directly irradiating a surface of a part or the like with a laser beam and marking a part of the surface by thermal decomposition or evaporation by touching has been used. However, this marking method has a disadvantage that it is difficult to obtain clear marking depending on the material.

[0003] As a method for solving the above-mentioned problems, a laser marking ink is applied to the surface of an object to be marked such as an electronic part, an electric part, a housing, a package, etc., and the surface layer is scribed by a laser beam. The use of a material capable of laser marking has been performed for the method of performing the marking, or for the marking itself.
However, when an attempt is made to perform colored laser marking with a laser, for example, JP-A-61-69488 and JP-A-1-306285 disclose that an inorganic lead compound is
No. 204888 describes manganese violet and cobalt violet, and JP-A-63-239059 describes metal compounds such as mercury, cobalt, copper, bismuth and nickel. However, since these compounds are mainly heavy metals, they have problems such as safety and environmental impact.
There is also a method of using a thermosensitive recording material represented by a combination of a leuco dye and a developer as a material that develops black without using heavy metals that cause environmental pollution.However, depending on the resin, a composition or a composition is used. However, there is a problem that the color is already formed when the product is used as a product and cannot be used for marking.

Japanese Patent Application Laid-Open No. 60-155493 proposes yellow iron oxide as an environmentally friendly metal compound capable of laser marking. However, since yellow iron oxide is colored in ocher, it may be mixed with a resin or the like. When the laser marking is carried out, it becomes dirty and ocher, and the contrast between the brown to brown mark and the background is poor, and the visibility is poor.

[0005]

SUMMARY OF THE INVENTION There is a need for a laser marking composition which does not use a heavy metal compound, does not cause environmental pollution, has a clear background and is capable of forming a highly visible colored marking excellent in contrast by laser light. Have been.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a laser marking composition satisfying the above performance can be obtained. . That is, the present invention provides (1) a laser marking composition comprising a compound that emits color by laser light and a fluorescent dye, (2) a composition of (1), wherein the fluorescent dye is a basic organic dye, (3) The composition according to (2), wherein the basic organic dye is a basic organic pigment.
(4) The composition according to (3), wherein the basic organic pigment is a naphthalic acid-based organic pigment, and (5) the naphthalic acid-based organic pigment is represented by the following general formula (1):

[0007]

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(Wherein R1 and R2 each represent a lower alkyl group). The composition of (4), which is a compound represented by the following general formula (2):

[0009]

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(Wherein R3 and R4 each represent a lower alkyl group or a halogen atom). The composition (4), wherein the basic organic pigment is a coumarin organic pigment. Certain compositions (3) and (8) coumarin-based organic pigments have the following general formula (3)

[0011]

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(Wherein R5 and R6 represent a C1 to C5 alkyl group, cyclohexylphenyl group or alkyl-substituted phenyl group), a composition of (7), and (9) a coumarin-based compound. The organic pigment is represented by the following general formula (4)

[0013]

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(Wherein R7 and R8 represent a C1 to C5 alkyl group, cyclohexylphenyl group or alkyl-substituted phenyl group) (7), (10) laser light (1) The composition according to any one of (1) to (9), wherein the compound that develops color in (1) to (9) contains an epoxy resin and a curing agent and / or a curing accelerator. (10) An article having a cured coating of the composition according to any one of (10), (12), and (13) a powder coating comprising a powder of the composition according to (11).

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The laser marking composition of the present invention is characterized by containing a compound which emits color by laser light and a fluorescent dye. The compound that develops color by laser light (laser-marking color developing agent) may be any compound that produces a color by laser light, such as yellow iron oxide, nickel carbonate, cobalt carbonate, copper oxalate, and the like.
A combination of more than one species may be used. Of these,
From the viewpoints of safety and coloring, yellow iron oxide is preferred.

Examples of fluorescent dyes include basic pigments such as naphthalic acid organic pigments and coumarin organic pigments, basic dyes such as methine basic dyes, xanthene basic dyes such as rhodamine 6G, zinc sulfide, and the like. Inorganic pigments such as zinc silicate, zinc cadmium sulfide, calcium sulfide, strontium sulfide, calcium tungstate, and daylight fluorescent pigments. Of these, organic dyes are preferred from the viewpoint of safety and colorability, more preferably basic organic dyes such as basic pigments and basic dyes, and still more preferably basic organic pigments. A basic organic dye is a dye having an aromatic ring in a molecule and an amino group bonded to the aromatic ring.

The naphthalic acid-based organic pigment is, for example, a basic pigment represented by the above formula (1) or (2). The coumarin-based organic pigment is, for example, a compound represented by the above formula (3) or (4). Basic pigments. Examples of the methine basic dye include a compound represented by the following formula (5).

[0018]

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(Wherein R9 is a methyl group or an ethyl group,
R10 and R11 are respectively a lower alkyl group, R12 is a hydrogen atom, a lower alkyl group or a lower alkoxyalkyl group, X is Cl ion, HSO4 ion, 1 / 2S
Represents O4 ion or 1/2 ZnCl4 ion. )

In the above formulas (1) to (5), R1 to R
8, Examples of the C1 to C5 alkyl group in R10 to R12 include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. Examples of the halogen atom for R3 and R4 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R5, R6, R7,
Examples of the alkyl-substituted phenyl group for R8 include a methylphenyl group, an ethylphenyl group, a propylphenyl group,
(C1-C4) such as butylphenyl group and pentylphenyl group
5) Alkyl-substituted phenyl groups. R10, R
Examples of the 11 lower alkoxyalkyl groups include a methoxyethyl group, an ethoxymethyl group, a propyloxymethyl group, a butyloxymethyl group, a pentyloxymethyl group and the like.

Typical examples of the fluorescent dye include a compound (compound (a)) in which both R1 and R2 in the formula (1) are butyl groups, and a compound in which both R3 and R4 in the formula (2) are methyl groups. (Compound (b)), a compound of formula (3) wherein both R5 and R6 are ethyl groups (compound (c)), and a compound of formula (4) wherein both R7 and R8 are ethyl groups ( Compound (d)) is exemplified. The compounds of the formulas (1) and (2) are of the formula (4) according to the description of JP-B-39-7932, and the compounds of the formula (3) are of the formula (4) according to the description of JP-B-54-13257. The compound of the formula (1)
Each of them is manufactured according to the description in Japanese Patent No. 87730.

The amounts of the color former and the fluorescent dye used are desirably as small as possible from the viewpoint of coloring. However, the amount is preferably 1 to 30 in the laser marking composition of the present invention in consideration of the laser marking property. %, Preferably from 2 to 20% by weight, more preferably from 3 to 10% by weight. The fluorescent dye depends on the desired hue,
At 2 to 5% by weight, preferably 0.3 to 3% by weight, more preferably 0.5 to 2% by weight, the color becomes clear and the contrast with the mark increases.

The laser marking composition of the present invention is obtained by uniformly dispersing the above two components in a medium. The medium is not particularly limited, and may contain a coloring agent for laser marking, as long as it can be marked by irradiating a laser beam, for example, water or an organic solvent containing a binder, a thermosetting resin, Examples thereof include a thermoplastic resin and a photocurable resin, and a resin containing an epoxy resin, a curing agent and / or a curing accelerator as an essential component is preferable. Those containing an epoxy resin as a medium are preferably used as a powder coating in the form of a powder. In the case of water or an organic solvent containing a binder, it is preferably used as an ink for laser marking.

As the epoxy resin, for example, bisphenol A, bisphenol F, bisphenol S, 4,
4′-biphenylphenol, 2,2′-methylene-bis (4-methyl-6-tert-butylphenol),
2,2'-methylene-bis (4-ethyl-6-tert
-Butylphenol), 4,4′-butylylene-bis (3-methyl-6-tert-butylphenol),
1,1,3-tris (2-methyl-4-hydroxy-5
-Tert-butylphenol), trishydroxyphenylmethane, pyrogallol, phenols having a diisopropylidene skeleton, phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene, and polyphenol compounds such as phenolized polybutadiene. Glycidyl etherified polyfunctional epoxy resin, phenol, cresols, ethylphenols, butylphenols, octylphenols, bisphenol A, bisphenol F, bisphenol S,
Glycidyl ethers of various novolak resins such as novolak resins, phenol novolak resins containing a xylylene skeleton, phenol novolak resins containing a dicyclopentadiene skeleton, phenol novolak resins containing a fluorene skeleton, and aliphatics such as cyclohexane, which are made from various phenols such as naphthols Alicyclic epoxy resin having a skeleton, isocyanuric ring, heterocyclic epoxy resin having a heterocyclic ring such as a hydantoin ring, brominated bisphenol A,
Epoxy resins obtained by glycidylation of halogenated phenols such as brominated bisphenol F, brominated bisphenol S, brominated phenol novolak, brominated cresol novolak, chlorinated bisphenol S, and chlorinated bisphenol A are exemplified.

Examples of the curing agent include polyphenols, acid anhydrides, phenol novolaks, amines and the like.
Examples of the polyphenol include trishydroxyphenylmethane, phenols having a diisopropylidene skeleton, phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene, phenolated polybutadiene, and 2,2′-methylene- Bis (4-methyl-6-tert-butylphenol), 2,2′-
Methylene-bis (4-ethyl-6-tert-butylphenol), 4,4′-butylylene-bis (3-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy) Bisphenols such as -5-tert-butylphenol), bisphenol A, bisphenol F, bisphenol S, bisphenol C, bisphenol O (4,4'-dihydroxybiphenyl ether), and 4,4'-biphenylphenol. These phenolic curing agents include methyl, ethyl, propyl, butyl, octyl and other C1-12 alkyl groups, fluorine, chlorine, bromine halogen groups, nitro groups, methoxy groups, ethoxy groups, propoxy groups, It may have one, two or more kinds of various alkyl-substituted amino groups typified by a C1-4 alkoxy group such as a butoxy group, an amino group, a dimethylamino group and a diethylamino group.

Examples of the acid anhydride include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol trimellitic anhydride, biphenyltetracarboxylic anhydride, glycerol tris Aromatic carboxylic anhydrides such as trimellitic anhydride, dodecenyl succinic anhydride, polyazeleic anhydride, polysebacic anhydride, polycarboxylic acid anhydrides such as polydodecane dianhydride, tetrahydrophthalic anhydride, Methylhexahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, hetonic anhydride, hymic anhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1 , 2-dicarboxylic anhydride, trialkyltetrahydroanhydride lid Acid - maleic acid adduct, alicyclic carboxylic acid anhydrides such as chlorendic acid.

Examples of the amines include ethylenediamine, diethylenetriamine, triethylenetetramine,
Tetraethylenepentamine, polyoxypropylenediamine, polyoxypropylenetriamine, mensendiamine, isophoronediamine, bis (4-amino-3-
Methylzinclohexyl) methane, diaminozinclohexylmethane, bis (aminomethyl) cyclohexane,
N-aminoethylpiperazine, 3,9-bis (3-aminopropyl) 2,4,8,10-tetraoxaspiro (5,5) undecane, m-xylenediamine, α-
Aliphatic amines such as (m / p aminophenyl) ethylamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiethyldimethylmethane, α, α'-bis (4-aminophenyl) -p-diisopropylbenzene, diamino Examples thereof include aromatic amines such as diphenyl ether, isocyanates of these amines, dicyandiamide, and hydrazides of various carboxylic acids.

Phenol novolaks include phenol, cresols, ethylphenols, butylphenols, octylphenols, bisphenol A,
Novolak resins, such as novolak resins, phenol novolak resins having a xylylene skeleton, phenol novolak resins having a dicyclopentadiene skeleton, and phenol novolak resins having a fluorene skeleton, which are made from various phenols such as bisphenol F, bisphenol S, and naphthols, are exemplified. These curing agents can be used alone or in combination of two or more. The amount used is epoxy group 1.
The equivalent is usually 0.5 to 1.4 equivalent, preferably 0.6 to 1.2 equivalent, more preferably 0.8 to 1.0 equivalent.

Examples of the curing accelerator include imidazoles, amides, diaza compounds, organic ammonium salts,
Examples include phosphines and amino-containing phenols.

The imidazoles include 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-imidazole
Phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1
-Cyanoethyl-2-undecylimidazole, 2,4
-Diamino-6 (2'-methylimidazole (1 '))
Ethyl-s-triazine, 2,4-diamino-6 (2 ′
-Undecylimidazole (1 ′)) ethyl-s-triazine, 2,4-diamino-6 (2′-ethyl, 4-methylimidazole (1 ′)) ethyl-s-triazine,
2: 4-diamino-6 (2′-methylimidazole (1 ′)) ethyl-s-triazine.isocyanuric acid adduct, 2-methylimidazole isocyanuric acid 2: 3
Adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-3,5-dihydroxymethylimidazole, 2-phenyl-4-hydroxymethyl-5-methylimidazole, 1-cyanoethyl-2-phenyl-
Various imidazoles such as 3,5-dicyanoethoxymethylimidazole, and those imidazoles and phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, naphthalenedicarboxylic acid, maleic acid,
Salts with polyvalent carboxylic acids such as oxalic acid and the like can be mentioned.

Examples of the amides include dicyandiamide, and examples of the diaza compounds include 1,8
-Diaza-bicyclo (5.4.0) undecene-7, etc.
And salts thereof with phenols, the above-mentioned polycarboxylic acids or phosphinic acids. Examples of the organic ammonium salts include tetra (C1-C5) alkylammonium bromide such as tetrabutylammonium bromide and tetraethylammonium bromide. Examples of the phosphines include phenyl-containing phosphines such as triphenylphosphine, tetraphenylphosphonium bromide, triphenylphosphine / toluene bromide, and tetraphenylphosphonium tetraphenylborate. Examples thereof include amino (C1-C5) alkylphenols such as 2,4,6-trisaminomethylphenol.

Preferred curing accelerators include, for example, 2-
Methylimidazole, 2-phenylimidazole, 2-
Undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-
Imidazoles such as methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole and terephthalic acid, trimellitic acid,
Salts with pyromellitic acid, 2,4-diamino-6 (2 ′
-Undecylimidazole (1 ′)) ethyl-s-triazine, 2,4-diamino-6 (2′-ethyl, 4-methylimidazole (1 ′)) ethyl-s-triazine,
2: 4-diamino-6 (2′-methylimidazole (1 ′)) ethyl-s-triazine.isocyanuric acid adduct, 2-methylimidazole isocyanuric acid 2: 3
Adducts, 2-phenylimidazole isocyanuric acid adducts, and phosphines such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate, and more preferably 2,4-diamino-6 (2′-methylimidazole (1 ′) )) Ethyl-s-triazine,
2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-
Benzyl-2-phenylimidazole, 1-benzyl-
2-methylimidazole is a salt of terephthalic acid, trimellitic acid, pyromellitic acid, and triphenylphosphine. These curing accelerators can be used alone or in combination of two or more. The amount used is epoxy resin 1.
The amount is usually 0.01 to 7 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight with respect to 00 parts by weight.

The composition of the present invention may further contain, if necessary, additives such as an anti-bake agent such as benzoin, a leveling agent, a coupling agent and a flame retardant, and an inorganic filler. Examples of the inorganic filler include fused silica, crystalline silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, aluminum oxide, magnesium oxide, zirconium oxide,
Aluminum hydroxide, magnesium hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate,
Zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc. are preferred, and preferably fused silica, crystalline silica, calcium carbonate, aluminum oxide, zirconium oxide, aluminum hydroxide, magnesium carbonate, mica, and talc , Calcium silicate, aluminum silicate and lithium aluminum silicate, more preferably calcium carbonate, fused silica, crystalline silica, aluminum oxide and mica. These fillers may be used as a mixture of two or more kinds. Also 50% of that
Average particle size is 0.5 to 50 μm, preferably 1 to 30 μm
m, more preferably 2 to 20 μm, and the compounding amount is usually 20 to 17 parts by weight with respect to 100 parts by weight of the epoxy resin.
0 parts by weight, preferably 30 to 150 parts by weight, more preferably 50 to 140 parts by weight.

Examples of the coupling agent include a titanate coupling agent and a silane coupling agent. Examples of titanate-based coupling agents include isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tri (dioctyl phosphate) titanate, isopropyl tris (dioctyl pyrophosphate) titanate, and isopropyl tri (N-aminoethyl-aminoethyl). Monoalkoxyl type such as titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, bis (dioctyl pyrophosphate)
Chelate type such as ethylene titanate, quaternized type, tetraoctylbis (ditridecyl phosphite)
Titanate, tetra (2,2-diallyloxymethyl-
Coordinated types such as (1-butyl) bis (ditridecyl) phosphite titanate are exemplified.

As the silane coupling agent, for example, 3
-Glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4
A silane coupling agent having an epoxy group such as -epoxycyclohexyl) ethyltrimethoxysilane;
Silane coupling agents having an amino group such as (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3 Silane coupling agents having a mercapto group such as mercaptopropyltrimethoxysilane, silane coupling agents having a vinyl group such as vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxy Silane coupling agent having a cationic group such as silane hydrochloride, silane coupling agent having an unsaturated group such as 3-methacryloxypropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, etc. Halogen group of A silane coupling agent having the like.

As the flame retardant, inorganic flame retardants such as antimony trioxide, antimony pentoxide, tin oxide, tin hydroxide, molybdenum oxide, zinc borate, barium metaborate, red phosphorus, aluminum hydroxide, magnesium hydroxide, calcium aluminate, etc. Flame retardants, brominated flame retardants such as tetrabromophthalic anhydride, hexabromobenzene and decabromobiphenyl ether, and phosphoric flame retardants such as tris (tribromophenyl) phosphate. As the leveling agent, a molecular weight of acrylates such as ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate of 4
2,000 to 12,000 oligomers, epoxidized soybean fatty acid, epoxidized aviethyl alcohol, hydrogenated castor oil, benzoin and the like.

In the laser marking composition of the present invention, examples of the thermosetting resin used as a medium include polyester resin, acrylic resin, phenol resin, and polyimide resin. Examples of the thermoplastic resin include polyethylene and polypropylene. , Polyethylene terephthalate, ABS resin, vinyl chloride, polystyrene and the like. Further, water or an organic solvent containing a binder may be used as the medium.

Examples of the organic solvent include alcohols such as methanol, ethanol, propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, methyl cellosolve, ethyl cellosolve, and butyl cellosolve, methyl acetate, and ethyl acetate. , Propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, methyl benzoate, ethyl benzoate, dimethyl phthalate, diethyl phthalate, triethyl trimellitate Various carboxylic esters such as benzene, toluene,
Examples include aromatic solvents such as xylene and ethylbenzene, and glycol derivatives such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, and propylene glycol monomethyl ether acetate.

The laser marking composition of the present invention can be made into a powder form and used, for example, as a powder coating. To prepare the powder coating of the present invention, additives such as a coloring agent, a fluorescent dye, an epoxy resin, a curing agent and / or a curing accelerator, and if necessary, a filler, a coloring agent, and a flow controlling agent are added to a Henschel mixer. After dry-mixing using, for example, a melter treatment at 110 ° C. or lower using a kneader, an extruder or the like, the mixture may be cooled and solidified, finely pulverized and then classified. The particle size of the obtained powder composition is usually 10 to 180 μm.
And preferably 10 to 150 μm, more preferably 1 to 150 μm.
0 to 106 μm. When the laser marking composition of the present invention is a thermoplastic resin composition, it is obtained by melt-kneading a color former and a fluorescent dye with a resin pellet, a kneader, an extruder or the like, and then cooling.

The article having the composition of the present invention on its surface is not particularly limited as long as it is a substance to be marked with a laser beam. Examples of such an article include capacitors, ICs, hybrid ICs, varistors, thermistors, and substrates. Various parts such as electronic parts, mechanical parts such as gears, automobile parts such as motors, various containers, caps, beverage cans such as beer cans and juice cans, cans such as cans for cans, cards, labels, etc. Can be The substrate of the article is not particularly limited, such as paper, synthetic resin, metal, and wood products. In addition, the thickness of the coating film formed of the coating material for laser marking of the present invention obtained by drying and / or curing after coating on the surface of the article is not particularly limited, but is preferably 5 μm or more. Preferably 10 μm or more, more preferably 10 to 300
About μm is good. Further, when the composition for laser marking of the present invention is a thermoplastic resin composition, it can be used for various containers, caps, electric product parts, toys, stationery, and the like, which can be usually molded with plastic.

In order to manufacture the article of the present invention, for example, when the composition is a powder coating, known methods such as a flow dipping method, an electrostatic flow dipping coating, a spray electrostatic coating method, a spray hot melt method, and a molding method are used. Apply to the object by the method of
In the case of a liquid paint or ink, a conventionally known technique such as an air knife coater, a blade coater, a coating device such as a gravure printing machine, or a dip method, a spray method, a brush coating method, or a mold is used. After being coated by a casting method or the like, it can be obtained by curing with heat rays or energy rays such as ultraviolet rays. In the case of heat curing, the curing temperature is 90 to 250 ° C, preferably 110 to 230 ° C, and more preferably 130 to 210 ° C.
° C. When the composition is a thermoplastic resin composition, it can be obtained by a known molding method such as injection molding or extrusion molding.

By irradiating the article with a laser beam, a clear brown to brown mark can be provided on the surface of the article. Examples of the laser to be used include a carbon dioxide gas laser, a YAG laser, an excimer laser and the like, and a TEA carbon dioxide laser, a scanning carbon dioxide laser, and a YAG laser are preferable. As the laser light to be applied, for example, in the case of a TEA-type carbon dioxide laser, the output is 4.5 joules / cm 2 or less, preferably 1.0 to 3.5 joules / cm 2, and more preferably 1.5 to 3.0 joules. /
In the case of a square centimeter scanning carbon dioxide laser, the output is 5 to 100 watts or less, preferably 1 to 100 watts.
It is 0 to 90 watts or less, more preferably 15 to 80 watts or less.

[0043]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 4 and Comparative Examples 1 and 2 The components shown in Table 1 were uniformly stirred and mixed with a mixer or a blender, and heated and kneaded with a kneader or a roll.
After pulverization, the laser marking composition of the present invention is obtained. The composition thus obtained is placed in an aluminum cup,
Each was cured by heating at 150 ° C. for 1 hour to obtain a test piece for marking.

[0045]

Table 1 Example 1 Comparative Example 1 2 3 4 1 2 R-304 100 100 100 100 100 100 100 HF-1 15 15 15 15 15 15 15 2MZ-A 11 1 11 1 RD-8 60 60 60 60 60 60 60 Yellow 48 55 55 55 10 CR-60 10 10 10 10 Compound (a) 1 Compound (b) 1 Compound (c) 1 Compound (d) 1 −−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−− Laser marking ○ ○ ○ ○ ○ ○ Contrast ◎ ◎ ◎ ◎ × ×

The mark criterion is as follows. Laser marking property ：: Color develops. ×: No coloring. Contrast ：: Marking part is immediately apparent and extremely good. ：: good. X: Marking part is not conspicuous and hard to read.

In Table 1, the contents of each compounding component are as follows. R-304: Bisphenol A type epoxy resin manufactured by Mitsui Petrochemical Co., Ltd. 2MZ-A: Curing accelerator (imidazole-based hardening accelerator manufactured by Shikoku Chemicals) HF-1: Meino Kasei phenol novolak resin RD-8: Tatsumori fused silica Yellow48 : Yellow iron oxide manufactured by Toda Kogyo CR-60: Titanium oxide manufactured by Shiraishi Kogyo Compound (a): Compound in which both R1 and R2 in Formula (1) are butyl groups Compound (b): R3 and R4 in Formula (2) Are both methyl groups Compound (c): a compound in which both R5 and R6 in Formula (3) are ethyl groups Compound (d): a compound in which both R7 and R8 in Formula (4) are ethyl groups

As is clear from Table 1, the composition of the present invention has a good contrast at the marking portion and the mark can be clearly read as compared with the comparative example. In addition, Yellow48
If is not used, a mark cannot be given.

[0049]

According to the present invention, since no heavy metal-containing compound is used, a composition for laser marking which does not cause environmental pollution and has excellent contrast, which produces a clear brown to brown color by laser light, can be obtained.

Continuation of front page (72) Inventor Akiki Niimoto 7-6-2-906 Suzuya, Yono-shi, Saitama

Claims (13)

[Claims] 1. A laser marking composition comprising a compound which develops a color by laser light and a fluorescent dye. 2. The method according to claim 1, wherein the fluorescent dye is a basic organic dye.
Composition. 3. The composition according to claim 2, wherein the basic organic dye is a basic organic pigment. 4. The composition according to claim 3, wherein the basic organic pigment is a naphthalic acid-based organic pigment. 5. A naphthalic acid-based organic pigment represented by the following general formula (1): ## STR1 ## 5. The composition according to claim 4, which is a compound represented by the formula: wherein R1 and R2 each represent a lower alkyl group. 6. A naphthalic acid-based organic pigment represented by the following general formula (2): The composition according to claim 4, which is a compound represented by the formula: wherein R3 and R4 each represent a lower alkyl group or a halogen atom. (2) 7. The composition according to claim 3, wherein the basic organic pigment is a coumarin organic pigment. 8. A coumarin-based organic pigment represented by the following general formula (3): The composition according to claim 7, which is a compound represented by the formula: wherein R5 and R6 represent a C1 to C5 alkyl group, a cyclohexylphenyl group or an alkyl-substituted phenyl group. 9. The coumarin-based organic pigment is represented by the following general formula (4): In the formula, R7 and R8 represent a C1 to C5 alkyl group, a cyclohexylphenyl group, or an alkyl-substituted phenyl group. The composition according to claim 7, which is a compound represented by the formula: 10. The composition according to claim 1, wherein the compound that develops color by laser light is yellow iron oxide. 11. The composition according to claim 1, comprising an epoxy resin and a curing agent and / or a curing accelerator. 12. An article having a cured coating of the composition of claim 11. 13. A powder coating comprising a powder of the composition according to claim 11.