JPH0826211B2 - Laser beam marking material - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a laser Bee made of a thermosetting resin composition excellent in the absorption of the laser beam
The present invention relates to a marking material and a method for forming an image on the surface of the marking material with a laser beam.

[0002]

2. Description of the Related Art Heretofore, in order to display characters and symbols on the surface of articles such as electronic parts, a transfer printing method using a thermosetting ink or an ultraviolet curable ink has been carried out. However, this method involves preventing dust from adhering to the article surface and adjusting the ink familiarity to the article surface, and
There is a problem that a curing step of ink is required after printing. In addition, as an alternative method to the printing method, on the surface of the molded product of the resin previously blended with the laser markin material,
A method of irradiating a laser beam to form an image on the surface thereof has been proposed.

As a laser marking material, a thermally decomposable and / or thermochromic colorant, for example, a lead compound (Japanese Patent Application No. 1-2222994, Japanese Patent Application No. 2-48984), copper oxalate (Japanese Patent Laid-Open No. 3-9898). -52945), cobalt oxalate (JP-A-3-59062), aluminum acetylacetone (JP-A-3-59063), bismuth oxalate (JP-A-3-59064), silver acetate (JP-A-3-5).
9065), metal titanate (JP-A-3-10884).
No.) etc. are known. However, the thermosetting resin composition containing these marking materials has a problem that it does not give a clear mark, and is not yet satisfactory.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a laser beam marking material comprising a thermosetting resin composition which gives a clear image by laser beam marking, and a laser beam marking material thereof.
It is an object of the present invention to provide a laser marking method for the surface of a marking material .

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, the thermal decomposition and / or thermochromic colorants, heat containing cordierite
Laser beam marking material composed of curable resin composition
Fees are provided. Further, according to the present invention, cordierite is contained together with a thermally decomposable and / or thermochromic colorant.
The surface of the marking material consisting of the thermosetting resin composition is irradiated with a laser beam to form an image.
A featured laser beam marking method is provided.

[0006] array made of a thermosetting resin composition of the present invention
The ZerBeam marking material is characterized in that it contains cordierite together with a thermally decomposable and / or thermochromic colorant. The present inventors have found that the thermosetting resin composition containing cordierite has a high laser beam absorption property of the cordierite, and therefore when irradiated with a laser beam, only the laser beam irradiation portion is heated to a significantly high temperature. In addition to finding that the resin at that location is thermally decomposed and instantly removed, and if this composition contains a thermally decomposable and / or thermochromic colorant in advance, it is It has been found that a clear image can be efficiently formed by thermal decomposition or thermal discoloration of the colorant. The present invention has been made based on such findings.

The cordierite used in the present invention is represented by the composition formula 2MgO.2Al ₂ O ₃ .5SiO ₂ , has excellent heat resistance, and does not decompose when irradiated with a laser beam. Especially talc-alumina-
Kaolin synthetic products are good with little mullite impurities. Cordierite is used in the form of powder, and the smaller the particle diameter, the more preferable, but generally, the average particle diameter is 5
It is 0 μm or less, preferably 0.5 to 15 μm. The higher the amount of cordierite compounded with the resin, the more preferable, but the amount of compounded compound is 10 parts by weight or more, preferably 50 to 300 parts by weight, per 100 parts by weight of the resin, when other inorganic fillers are not used in combination. Also, cordierite can be used in the form of a mixture with other inorganic fillers. Such inorganic fillers include alumina, silica, magnesia, antimony trioxide, calcium carbonate,
Examples include magnesium carbonate, mica, clay, sepiolite, zeolite and the like. The average particle size of these inorganic fillers is 0.3 to 50 μm, preferably 0.5 to 30 μm. The filler has a thixotropic property, for example, ultrafine particles of silica or alumina having an average particle diameter of 100 nm or less, aluminum hydroxide having an average particle diameter of 3 μm or less, fibrous magnesium oxalphate, fibrous material. Silica, fibrous potassium titanate, scaly mica, montmorillonite-organic base double salt called so-called bentonite, and the like can be used.
In the present invention, silica is particularly preferably used as the inorganic filler used in combination with cordierite. The silica includes spherical and destructive amorphous silica (fused silica) as well as crushed crystalline silica and the like, and the average particle size thereof is 50 μm or less, preferably 0.5 to 30 μm. When other cordierite is used as a mixture with the inorganic filler, the mixing ratio of the cordierite is 1%.
5 parts by weight or more, preferably 10 to 3 parts by weight with respect to 00 parts by weight
It is preferable that the proportion is 00 parts by weight. The cordierite content in the mixture of the cordierite and the other inorganic filler is 5% by weight or more, preferably 10% by weight or more,
It is more preferably at least 20% by weight.

The thermally decomposable and / or thermochromic colorants used in the present invention include those which decompose and disappear by undergoing a thermal decomposition reaction or a thermochromic reaction at high temperatures, those which lose their coloration, and other colors. Any one that changes color or a white or colored colorant that produces a more vivid white or coloring is used. Specific examples of such a thermochromic colorant include:
The above-mentioned conventionally known various coloring agents, for example, red lead, basic lead phosphite sulfite, basic lead phosphite, basic lead sulfite,
Copper oxalate, cobalt oxalate, acetylacetone aluminum, bismuth oxalate, metal titanate, basic nickel carbonate, basic copper carbonate, bismuth oxide, ferric hydroxide, ammonium vanadate, hydrated alumina, zinc borate, Examples thereof include zinc carbonate, carbon black and various organic dyes and pigments. When the colorant used is discolored to another color by laser beam heating, another colored or white image with the background color of the molded product before heating is formed on the cured molded product. On the other hand, when the coloring agent to be used is decomposed and disappears by heating with a laser beam, another color or white color is formed on the cured molded product with the color of the molded product before heating as the background color. In this case, the color of the image formed on the molded product is the color before the addition of the colorant that disappears due to its thermal decomposition, for example, when the cured molded product contains a non-pyrolytic colorant, the colorant When a white inorganic filler or inorganic pigment is included, the color becomes white.
Further, in the case of a white cured molded article containing a thermally decomposable and / or thermochromic colorant in which the color before heating is white and the color after heating is colored, coloring on the white molded article by laser beam heating. An image is formed. When a heat decomposable and / or thermochromic colorant is added to the thermosetting resin, these colorants may be added alone or in the form of a mixture so as to obtain a desired coloring. In this case, if necessary, a colorant such as red iron oxide and the like, which is not thermally discolored by heating and has good thermal stability, can be used in combination. The content of the colorant in the entire composition is 0.1 to 50% by weight, preferably 1 to 30% by weight.

Examples of the thermosetting resin used in the present invention include epoxy resin, phenol resin, bismaleimide resin, unsaturated polyester resin, urethane resin and the like.

The preferred resin used in the present invention is an epoxy resin, and the epoxy resin composition will be described in detail below. Any epoxy resin may be used as long as it exhibits a liquid or solid state at room temperature, and conventionally known resins can be used. Examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type or cresol novolac type epoxy resin, alicyclic epoxy resin, hydrogenated bisphenol A type or AD type epoxy resin, propylene glycol. Diglycidyl ether, aliphatic epoxy resin such as pentaerythritol polyglycidyl ether, epoxy resin obtained from aliphatic or aromatic carboxylic acid and epichlorohydrin, epoxy resin obtained from aliphatic or aromatic amine and epichlorohydrin,
Examples thereof include a heterocyclic epoxy resin, a spiro ring-containing epoxy resin, and an epoxy modified resin. If necessary, a thermoplastic resin can be mixed with the epoxy resin.

An acid anhydride is preferably used as the curing agent for the epoxy resin. Aliphatic and aromatic acid anhydrides are used as the acid anhydride, but aromatic acid anhydrides are preferably used. Specific examples of the acid anhydride include, for example, phthalic anhydride, trimellitic anhydride,
Pyromellitic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic acid anhydride, ethylene glycol-anhydrotrimellitate, glycerol-trisanhydrotrimellitate, 5- (2,5-dioxotetrahydro Frill) -3-
Methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, tetrahydrophthalic acid anhydride, 4,4′-oxydiphthalic acid anhydride and the like can be mentioned. Also, as a curing agent,
Other than the above-mentioned acid anhydride, other curing agents can be used. Examples of such a curing agent include mercaptan-based, amine-based, polyamide-based, boron-based, dicyandiamide-based, hydrazide-based, imidazole-based, phenol-based, amineimide-based curing agents, etc., but preferably phenol Resin is used. The proportion of the curing agent used is 0.5 to 1.5 equivalents, preferably 0.7 to 1. 1 equivalent of functional groups per epoxy equivalent of the epoxy resin.
It is a ratio of 2 equivalents.

When an acid anhydride is used as a curing agent, it is preferable to use a phenol resin together. Such a phenol resin which is preferably used in combination is a resin which is synthesized from phenols and formaldehyde and contains two or more OH groups in one molecule. Examples thereof include phenol novolac resin, cresol novolac resin, t-
There are butylphenol novolac resin, octylphenol novolac resin, nonylphenol novolac resin, bisphenol novolac resin and the like. Further, the phenol resin may be a mixture of the above various phenol resins, and in the production thereof, phenol and other phenols, for example, one or more of bisphenol A, bisphenol F, butylphenol, nonylphenol and the like. The mixed phenols may be used as a raw material, and formaldehyde is reacted with this. The acid anhydride used in the present invention may be melt-kneaded with the phenol resin in advance and mixed in the phenol resin.

A curing accelerator may be added to the epoxy resin composition, if necessary. As the curing accelerator, various compounds conventionally used for epoxy resins can be used. Specifically, tertiary amines such as triethylamine, N, N-dimethylbenzylamine, 2,4,6-tris (dimethylaminomethyl) phenol, N, N-dimethylaniline: 2-methylimidazole, 2-phenyl Imidazole compounds such as imidazole; various salts of imidazole compounds such as imidazole compounds such as triazine salts, cyanoethyl salts, cyanoethyl trimellitate salts; metal compounds such as zinc acetate and sodium acetate; quaternary ammonium salts such as tetraammonium bromide Other examples include amide compounds, peroxides, azo compounds, cyanate compounds, isocyanate compounds, triphenylphosphine, and DBU phenol novolac salts. The amount of the curing accelerator used is 0.05 to 10 parts by weight with respect to 100 parts by weight of the epoxy resin,
It is preferably 0.1 to 5.0 parts by weight.

The epoxy resin composition contains, in addition to the above components,
Flame retardants such as hexabromobenzene, antimony trioxide, and tetrabromobisphenol A, if necessary;
Zirco aluminum-based, silane-based, titanium-based coupling agents, leveling agents composed of acrylic acid ester oligomers, butyral resins, rubber components (CTBN,
NBR, etc.), polyester resin, etc. can be contained in appropriate amounts.

[0015]

The laser beam marking material of the present invention is in a solid or liquid form and is used as a molding material or a coating material. When used as a molding material, examples of the molding method include a transfer molding method, an injection molding method, a compression molding method, a cast molding method, and a dipping molding method.
When it is used as a coating material, the coating method includes a fluidized dipping method, an electrostatic spray method, a brush coating method and the like. When using the laser beam marking material of the present invention as a liquid epoxy resin composition, an epoxy resin,
A liquid mixture containing a filler and other additive components and a liquid mixture containing a curing agent and a curing accelerator are prepared, and both are mixed to form a liquid epoxy resin composition, which is used as a molding material or coating material.

With respect to a molded product or a coated product of the laser marking material comprising the thermosetting resin composition of the present invention, an image of a clear color tone different from the surface color of the molded product is formed on the surface of the molded product by a laser beam. Alternatively, marks can be formed. Specific examples of the article to be laser-marked include, for example, capacitors coated with a surface resin,
In addition to electronic / electrical components such as resistors, diodes, and ICs, various types such as resin casings for sealing can be used. As the laser beam, a near infrared ray having a wavelength of 10 to 11 μm, particularly a wavelength of 10.6 μm as a main wavelength is used. As such a laser beam marking generator, various known devices such as a carbon dioxide laser beam marking generator and a YAG laser generator are used.

[0017]

Next, the present invention will be described in more detail with reference to examples. Example 1 Epoxy resin compositions having the component compositions shown in Table 1 to Table 6,
Apply 0.5 mm thickness on the surface of aluminum metal piece (length: 50 mm, width: 50 mm, thickness: 1.5 mm), and
A cured resin film was formed by heating at 00 ° C. for 3 hours. In addition,
Each of the thermochromic colorants shown in Tables 1 to 6 is a color that changes to another colored color by heating. Next, a wavelength of 10.6 is applied to the surface of the sample having this cured resin film.
A mark was formed by irradiating a laser beam having a main wavelength of μm. In this case, the laser beam marking device used was an IEA CO ₂ laser, Unimark 400 4J (Joule) type (manufactured by Ushio Inc.). The thickness of the mark formed in this case is 0.2 mm.
Met.

The visibility (readability) of the sample marked as described above was evaluated according to the following criteria. [Visibility] (1) Discoloration 0: Almost no discoloration 1: Poor discoloration 2: Discoloration slightly poor 3: Normal discoloration 4: Discoloration better than normal 5: Discoloration very good (2) Image uniformity ×: Image is missing Δ: Image is partially blurred ○: Image is uniformly displayed ◎: Image is uniformly displayed

The specific contents of the substances shown in the table below are as follows. (1) Acid anhydride A: Methyltetrahydrophthalic anhydride (2) Acid anhydride B: Benzophenonetetracarboxylic acid anhydride (3) Phenolic resin: Phenol novolac resin (Tamanor 754, hydroxyl equivalent 104, Arakawa Chemical Industries, Ltd.) (4) BDMA: benzyldimethylamine (5) TPP: triphenylphosphine (6) Silica: “Crystallite A-1” (Tatsumori Co., Ltd.), average particle diameter: 12 μm (7) Cordierite: SS-200 Marusu Glaze Co., Ltd., average particle size: 7 μm (8) Aluminum hydroxide: " Hijilite H-31"
(Manufactured by Showa Light Metal Co., Ltd.), average particle diameter: 17 μm (9) Typake R-830: rutile type titanium oxide,
White pigment, manufactured by Ishihara Sangyo Co., Ltd. (10) Cyanine blue PI: Phthalocyanine pigment

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

[0024]

[Table 5]

Example 2 An experiment was conducted in the same manner as in Example 1 except that the epoxy resin compositions having the component compositions shown in Tables 7 to 9 were used. The results are shown in Tables 7-9. The thermally decomposable colorant used in these compositions is converted into a clear white product by heating. Further, Typake R-830 used as an auxiliary agent is a white pigment, and red iron oxide is a color pigment that does not discolor by heat.

[0026]

[Table 6]

[0027]

[Table 7]

[0028]

[Table 8]

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-2-174146 (JP, A) JP-A-4-183741 (JP, A) JP-A-4-183742 (JP, A) JP-A-4-174742 183743 (JP, A) JP-A-62-143981 (JP, A)

Claims (7)

[Claims] 1. A laser beam marking material comprising a thermosetting resin composition containing cordierite together with a thermally decomposable and / or thermochromic colorant. 2. The laser beam marking material according to claim 1, wherein the thermally decomposable and / or thermochromic colorant causes coloring other than white upon heating. 3. The laser beam marking material according to claim 1, wherein the thermally decomposable and / or thermochromic colorant is one which disappears or produces a white color when heated. 4. The cordierite content is 10 parts by weight or more per 100 parts by weight of the thermosetting resin.
Laser beam marking material according to any one of 3 above. 5. The laser beam marking material according to claim 1, which contains a filler other than cordierite. 6. The laser beam marking material according to claim 1, wherein the thermosetting resin is an epoxy resin. 7. A laser beam marking method comprising irradiating a surface of the laser beam marking material according to claim 1 with a laser beam to form an image.