JPH03281286A - Laser marking method and resin composition for laser marking - Google Patents

Abstract

PURPOSE:To perform marking enhanced in visibility by irradiating the surface of an object composed of a resin composition containing a non-black organolead compound and a resin with laser beam to apply marking to the object. CONSTITUTION:Marking is applied to an object composed of a resin composition containing a non-black organolead compound and a resin by irradiating the surface thereof with laser beam and the laser marking resin composition is obtained by adding the non-black organolead compound to the resin. As the non-black organolead compound to be used, lead stearate, basic lead stearate, lead octanate, lead myristate, lead naphthanate and lead oleate are designated. As the laser marking resin composition, a molding material or coating composition wherein the non-black organolead compound is contained in a resin is designated. This laser marking resin composition is characterized by that the organolead compound is stably dispersed in the resin and sharp black marking can be easily applied to the surface of the object composed of this composition by irradiating the object with laser beam.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser marking method for performing black marking using laser light, and a resin composition for laser marking suitable for marking by this method.

[Conventional technology]

The laser marking method is a method of marking marks, barcodes, images, etc. on the surfaces of metals, ceramics, polymeric organic materials, etc. using laser light.It is non-contact, has a fast marking speed, and is easy to automate and process. Recently, it has been widely used industrially because it is easy to manage.

[Problem to be solved by the invention]

Laser marking involves irradiating the surface of an object with a laser beam. ■ Changes in surface condition (roughening,
dents), ■Changes due to decolorization and discoloration of the colorant in the irradiated area (
For example, JP-A-56-144995, JP-A-60-
(No. 155493), or (2) Changes due to carbonization of the polymeric organic material in the irradiated area by incorporating a laser-absorbing substance such as polyolefin resin (for example, Japanese Patent Application Laid-Open No. 59-11
1892 Publication), etc., for marking.

However, the contrast between the laser beam irradiated area and the non-irradiated area is weak in the state change of the surface in (■), and irradiation with high-energy laser light is required to display the mark. In the method of color change, the color of the base material is limited by the coloring agent that can be bleached and discolored, and the heat resistance is low, making it easy to bleach and discolor. The use of molecular organic materials is limited to some areas, and other polymeric organic materials have drawbacks such as insufficient carbonization for masking and only surface roughening, resulting in unclear markings, and a solution is desired.

The present inventors have discovered a non-black inorganic lead compound as a compound that does not have the above-mentioned drawbacks and develops a black color, and has already filed a patent application for this compound (Japanese Patent Application No. 134107/1983).

However, since inorganic lead compounds are hydrophilic, there are problems with their dispersibility and dispersion stability in resins.

[Means to solve the problem]

As a result of intensive research in view of this situation, the present inventors found that
Products made of resin compositions containing non-black organic lead compounds and resins can be treated by simply irradiating the surface with laser light.
Clear and highly visible black markings can be easily made, and if the organic lead compound is not black, it can be colored in any color with a coloring agent, and the organic lead compound has a lipophilic group. Therefore, they discovered that they have good wettability with resins and have excellent dispersibility in resins compared to inorganic lead compounds, and have completed the present invention.

That is, the present invention provides a laser marking method characterized in that the surface of an object made of a resin composition containing a non-black organic lead compound and a resin is marked by irradiating a laser beam, and a non-black organic lead compound. The object of the present invention is to provide a resin composition for laser marking, which is characterized by containing a compound.

The laser used in the present invention is a pulsed laser that can apply energy of 0.5 joule/cm'' pulse or more to the irradiated surface, or a pulsed laser with an output of 0.5 joule/cm''.
A scanning laser with an output of W or more is preferable, such as carbon dioxide laser - carbon oxide laser, semiconductor laser, yttrium aluminum glass (YAG)
Lasers include excimer lasers, among others
- Tranversely Excited Ato
Mosphalic Pressure (T.E.A.
) type carbon dioxide laser and scanning type carbon dioxide laser are particularly preferred because they provide black markings with good visibility.

Examples of non-black organic lead compounds used in the present invention include lead stearate, basic lead stearate, lead 1 octoate, lead myristate, lead naphthenate, lead oleate, basic lead oleate, and lead phthalate. , basic lead phthalate, lead maleate, and basic lead maleate. These compounds may contain water of crystallization. Further, each of these may be used alone or as a mixture of two or more, a coprecipitate, or a complex salt. Moreover, among these, basic lead stearate, basic lead phthalate, and basic lead maleate are preferable in that black markings with good visibility can be obtained.

Note that the organic lead compound can be used after surface treatment with a fatty acid metal salt other than lead, a silicon-based, titanium-based, or aluminum-based coupling agent, or the like.

- Examples of the resin composition for laser marking of the present invention include, for example, molding materials and coating compositions in which a resin or the like contains a non-black organic lead compound. Further, examples of objects made of this resin composition include molded articles formed by molding the molding material, films coated with the coating composition and dried or cured, and the like. Incidentally, the coating composition herein includes, in addition to the usual overcoat composition, compositions for ink, binder, paint, surface finishing, and the like.

The content of the organic lead compound varies depending on the type and use of the resin composition, and may not be constant, or the content in objects made of the resin composition, such as molded products or coatings that are subjected to laser marking, is 1 to 1. The content is within the range of 90% by weight, especially when the content is 5% because clear and highly visible black markings are obtained and there is little deterioration in physical properties as molded products, coatings, etc.
A range of 50% by weight is preferred.

In the present invention, since the principle of discoloration to black is not due to carbonization of the organic material, there is no limitation on the resin that can be used to obtain a resin composition containing a non-black organic lead compound and a resin. The resin used for the molding material is not particularly limited, but includes thermoplastic resins that can be used for extrusion molding, transfer molding, injection molding, blow molding, cast molding, press molding, tape molding, etc., such as polyolefin resins. , vinyl chloride resin, polystyrene resin, acrylic resin, polyvinyl alcohol resin, polyester resin, polycarbonate resin, polyacetal resin,
Polyphenylene sulfide resin, polyether resin, polyamide resin, polyimide resin, fluorine resin; thermosetting resin, such as epoxy resin, phenol resin, amino resin, polyester resin, polyether resin, acrylic resin, diallyl phthalate resin, urethane resin, aniline resin, furan resin, polyamide resin, polyimide resin, silicone resin,
Examples include fluorine-based resins, and these may be used alone or in combination of two or more.

In addition, the type of resin used in the coating composition is not particularly limited, but room temperature drying type that can be applied with brush coating, spray coating, dip coating, electrostatic coating, powder coating, transfer, printing, etc. Paint resins, moisture-curable paint resins, thermosetting paint resins, etc., such as oil varnish, foil oil, shellac, cellulose resins, phenolic resins, alkyd resins, amine resins, xylene resins, toluene resins Resin, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, polystyrene resin, polyvinyl butyral resin, acrylic resin, diallyl phthalate resin, epoxy resin, urethane resin, polyester resin, polyether resin Resin, aniline resin, furan resin, polyimide resin, silicone resin, fluorine resin; light or electron beam curable resin, such as polyvinyl cinnamate ester resin, polyvinylbenzalacetophenone resin, polyvinyl henzal Acetophenone resin, polyvinylstyrylpyridine resin, polyvinyl alcohol resin, unsaturated polyester resin, acrylated oil, acrylated alkyd resin, acrylated polyester resin, acrylated polyether resin, acrylated epoxy resin resin, acrylated urethane resin,
Examples include macromonomers, oligomers, and monomers of acrylic resins, acrylated spiran resins, acrylated fluorine resins, polythiol resins, and cationically polymerized epoxy resins, and these can be used alone or in combination of two or more types. I can do it.

Incidentally, additives or solvents can be added to the resins used in the molding material and the coating composition, respectively, as necessary.

As additives, curing agents suitable for the resin used (amine curing agents, acid anhydride curing agents, imidazole curing agents, peroxide curing agents, etc.), drying agents (cobalt naphthenate, calcium nanthenate, etc.), Crosslinking agents, photoinitiators (acetophenone series, benzophenone series, Michler's ketone series, Henschel series, benzoin series, thioxanthone series, etc.), photosensitizers (butylamine series, triethylamine, diethyl 0 aminoethyl methacrylate, etc.), polymerization inhibitors (hydroquinone) , benzoquinone, sodium carbamate, etc.), dispersants (metallic soaps, surfactants, etc.), fluidity modifiers (bentonite, polymerized oil, sodium alginate, casein, Aerosil, organic/inorganic fine particles, etc.), sedimentation prevention agents (lecithin, etc.), flame retardants (antimony trioxide, phosphate esters, chlorine/bromine flame retardants, etc.), lubricants/mold release agents (
paraffin wax, polyethylene wax, montan wax, fatty acids, fatty acid amides, fatty acid esters, fatty alcohols, partial esters of fatty acids and polyhydric alcohols 1, surfactants, silicone compounds, bromine compounds, etc.), plasticizers (phthal acid derivatives, adipic acid derivatives, sepatic acid derivatives, trimellitic acid derivatives, epoxy derivatives, fatty acid derivatives, organic phosphoric acid derivatives, etc.), stabilizers (metallic soaps, organotin compounds, phosphorous ester compounds, etc.), antioxidants ( naphthylamine-based, diphenylamine-based, quinoline-based, phenol-based, phosphite-based compounds, etc.), ultraviolet absorbers (salicylic acid derivatives, benzophenone-based, benzotriazole-based, hindered amine-based compounds, etc.),
Reinforcing agents (glass fibers, carbon fibers, ceramic fibers, whiskers, etc.), coloring agents (inorganic pigments, organic pigments,
Any of the additives used in ordinary molding materials and paints, such as dyes, etc., can be added in appropriate amounts that are usually added.

In order to obtain a resin composition containing a non-black organic lead compound, a resin, and optionally additives, solvents, etc., it is sufficient to uniformly mix these by any method, and the method is not particularly limited.

Laser marking methods include, for example, using a laser beam as a spot of an appropriate size to move and scan the surface of the object or the object itself, or using a rectangular or circular laser beam such as a TEA-type carbon dioxide laser or a mask-type YAG laser. Examples include a method of cutting out the desired shape with a mask and irradiating it onto the surface of the object.

Examples of marking using the laser marking method of the present invention include capacitors, chip resistors, inductors,
Electronic parts such as connectors, cases, printed circuit boards, etc.; Electric wires, key tops, sheets, mechanical parts, housings for electrical products, coupons, cards, etc., products that are normally marked; Very small, transcription Items that cannot be marked, such as items that are extremely small and require highly accurate marking, such as barcodes.

The laser marking method of the present invention includes using a resin composition containing a non-black organic lead compound and a resin as all or part of the organic material part of the object, and coating the surface of the object with the resin composition. Forming the surface of the part desired to be marked with the resin composition by printing, coating or multi-layer molding on a part of the surface of the object, or by making a tape of the resin composition and pasting it on the surface of the object, Marking can be done by irradiating this with laser light, and it is possible to make black markings with high sensitivity and high visibility just by irradiating this laser light. Moreover, as long as it is not black, it may be colored in any color using a coloring agent or the like.

〔Example〕

3- The present invention will be explained in more detail by showing Examples and Comparative Examples below. Note that all parts in the examples are parts by weight.

Example 1 Polyethylene glycol diacrylate [Shin Nakamura Chemical (
Co., Ltd. NK Ester A-600) 100 parts photoinitiated diarrhea 5 parts [α-hydroxyisobutylphenone] basic lead stearate
20 parts The above composition was uniformly mixed with three rolls to obtain a coating composition. After coating this on a glass plate to a thickness of 20 μm, it was heated with a high-pressure mercury lamp for about 60 minutes.
It was cured by irradiation with ultraviolet rays of 00 mJ/cm" to obtain a white test. Next, when it was irradiated with laser light in the same manner as in Example 1, particularly clear markings were obtained.

Further, in order to confirm the dispersion stability, the above coating composition was left at 40° C. for one week, but no changes such as aggregation or sedimentation were observed.

14 Comparative Example 1 The surface of the test piece was irradiated with laser light in the same manner as in Example 1 except that the addition of basic lead phthalate was omitted, but no marking was obtained.

Comparative Example 2 A coating composition was obtained in the same manner as in Example 1 except that basic lead phosphite was used instead of basic lead phthalate.
．． When the composition was left for one week at 0'C, a precipitate of basic lead phosphite was observed at the bottom of the composition.

Although stirring was performed in an attempt to redisperse the mixture, redispersion was difficult.

Example 2 100 parts of polyethylene glycol diacrylate [NK Ester A-6001 photoinitiator manufactured by Shin-Nakamura Chemical Co., Ltd. 5 parts [α-hydroxyisobutylphenone] Basic lead maleate
30 parts] A white test was obtained in the same manner as in Example 1, except that the composition of the above two formulations was used, and then a TEA carbon dioxide laser (wavelength: 0.6 μm) was used on this test piece,
One pulse of laser light with an irradiation energy amount of 3 joules/cm" was applied through a prescribed mask, and another pulse of laser light with an irradiation energy of 6 joules/cm" was applied to another location on the specimen surface through a prescribed mask. One pulse was irradiated. 3 units/cm
Clear black markings were obtained on the surface of the test piece irradiated with laser light of No. 2, and particularly clear markings of black color were obtained on the surface of the test piece irradiated with laser light of 6 joules/cm 2 .

Comparative Example 3 A coating composition was obtained in the same manner as in Example 2 except that basic lead sulfite was used instead of basic lead maleate,
When the composition was left at 40'C for one week, a precipitate of basic lead sulfite was observed at the bottom of the composition. Although stirring was performed in an attempt to redisperse the mixture, redispersion was difficult.

Example 3 Bisphenol A type epoxy resin 100 parts [Epicron 850, manufactured by Dainippon Ink & Chemicals Co., Ltd., [1190] acid anhydride curing agent per epoxy 88 parts [Epicron 13-570, manufactured by the same company, acid anhydride equivalent 166] ] Curing accelerator 0. 4 parts [Benzyldimethylamine] Basic lead phthalate 4 parts The Epoquin resin composition of the above composition was mixed uniformly with three rolls to obtain a molding material, which was then cast between two glass plates to a thickness of 5 mm. After molding, it was cured at 80°C for 5 hours and at 160°C for 1 hour to obtain a white test piece. Next, this test piece was exposed to a TEA carbon dioxide laser (wavelength: 10.6 μm).
One pulse of laser light with an irradiation energy amount of 6 joules/cm2 was irradiated using a predetermined mask. Particularly clear black markings were obtained on the surface of the test piece.

Example 4 Polyethylene glycol diacrylate [Shin Nakamura Chemical (
Co., Ltd. NK Ester A-600) 7 100 parts Photoinitiator 5 parts [α-hydroxyisobutylphenone] Basic lead maleate
3 parts calcium oxalate
15 parts Example 1 except that the composition of the above formulation was used.
A white test was obtained in the same manner as above, and then a 1゛EA carbon dioxide laser (wavelength 10.6 μm) was used to irradiate the test piece with laser light with an irradiation energy amount of 3 joules/cm'' through a predetermined mask. A particularly clear black marking was obtained on the surface of the test piece.

Examples 5 to 7 Polyethylene glycol diacrylate [Shin Nakamura Chemical (
Co., Ltd. NK Ester A-500: 00 parts Photoinitiator 5 parts [α-Hydroxyisobutylphenone] 20 parts of the organic lead compound shown in Table 1
A coating composition was obtained by uniformly mixing at 8 mL, and this was coated on a glass plate to a thickness of 20 μm, and then cured by irradiating ultraviolet rays of about 600 millijoules/cm 2 with a high-pressure mercury lamp, and a white test piece was prepared. Obtained. Next, laser light was irradiated in the same manner as in Example 1, and the color development of the marking was evaluated using the following criteria. The results are shown in Table 1.

Table 1 ◎: Particularly clear ○: Clear △: Blurred ×: No color developed Example 8 A white test piece obtained in the same manner as in Example 3 was heated with a scanning carbon dioxide laser (wavelength 10.6 μm, output 20 W). use,
When laser light was irradiated at an output of 40% and a scanning speed of 300 mm/sec, clear black markings were obtained.

Example 9 100 parts of polyethylene resin [Santic-LD F2270, manufactured by Asahi Kasei Corporation, MI
7 g710mln] Basic lead phthalate 15 parts The above composition was thoroughly kneaded using a twin-screw extruder to obtain a molding material, and a white film with a thickness of 100 μm was obtained using an inflation molding machine at a processing temperature of 150°C. I got it. Next, when laser light was irradiated in the same manner as in Example 1, particularly clear black markings were obtained.

Comparative Example 4 A white film with a thickness of 100 μm was obtained in the same manner as in Example 9 except that basic lead phosphite was used instead of basic lead phthalate. Next, when laser light was irradiated in the same manner as in Example 1, a particularly clear black marking was obtained, but when the film was looked through, many aggregates of basic lead phosphite due to poor dispersion were observed. Ta.

Example 10 Polyethylene resin 100 parts [Sumikasen G308 manufactured by Sumitomo Chemical Co., Ltd., MI 200 g
710min) Basic lead phthalate 25 parts Copper phthalocyanine green 0.2 parts (C, 1, Pig
ment Green 7 part powder
0. 2 parts The composition of the above composition was thoroughly kneaded at 140°C using a Laboplast Mill manufactured by Toyo Seiki Co., Ltd. to obtain a molding material, which was then molded into a 1 mm thick sheet using a hot press machine and cooled. A green test piece was obtained. Next, when laser light was irradiated in the same manner as in Example 1,
Particularly clear black markings were obtained.

〔Effect of the invention〕

The resin composition for laser marking of the present invention has the following characteristics: 21. An organic lead compound is stably dispersed in the resin, and when the surface of an object made of this composition is irradiated with laser light, it can easily produce clear black markings. can do.

Claims (1)

[Scope of Claims] 1. A laser marking method characterized by marking the surface of an object made of a resin composition containing a non-black organic lead compound and a resin by irradiating a laser beam. 2. The method according to claim 1, wherein the resin composition is coated with a coating composition containing a non-black organic lead compound. 3. Claim 1, wherein the product made of the resin composition is a molded product formed by molding a molding material containing a non-black organic lead compound.
Method described. 4. The method according to claim 1, 2 or 3, wherein the non-black organic lead compound is one or more compounds selected from the group consisting of basic lead phthalate, basic lead maleate and basic lead stearate. . 5. The method according to claim 1, 2, 3 or 4, wherein a carbon dioxide laser is used as the laser beam. 6. A resin composition for laser marking, comprising a non-black organic lead compound. 7. The resin composition according to claim 6, which is a coating composition. 8. The resin composition according to claim 6, which is a molding material. 9. The resin according to claim 6, 7 or 8, wherein the non-black organic lead compound is one or more compounds selected from the group consisting of basic lead phthalate, basic lead maleate and basic lead stearate. Composition.