JP2770577B2 - Laser marking method and resin composition for laser marking - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes laser light,
The present invention relates to a laser marking method for performing white marking with high sensitivity and a resin composition suitable for laser marking by this method.

[0002]

2. Description of the Related Art Laser marking is a method of marking marks, barcodes, images, and the like by using laser light on the surface of metals, ceramics, organic polymers, and the like. quickly,
Due to the ease of automation and process control, it has recently been widely used industrially.

[0003] Laser marking involves irradiating the surface of an object with a laser beam to change the surface state of the irradiated portion due to etching (for example, JP-A-60-202119), and to change the colorant of the irradiated portion due to decolorization and discoloration ( For example, JP
No. 0-166488, JP-A-60-155493, JP-A-63-239059).

[0004]

However, when the surface condition changes, the contrast between the laser beam irradiated portion and the non-irradiated portion is weak, and high energy laser beam irradiation is required to display a mark. There is a drawback that the irradiation area is narrowed because the laser beam is narrowed down by an optical lens or the like.The method of decoloring / discoloring the colorant has the disadvantage that the color of the base material is limited by the colorant that can be decolorized / discolored, Materials that emit color by laser light have drawbacks such as low heat resistance, the use of coloring agents and additives that are easily decolored and discolored, so that the unirradiated portion is easily discolored, or decomposed during processing. From this point, for laser marking that has high thermal stability during processing or use, and that can be colored with low energy laser light with high sensitivity to enable marking of a large area at once, and that can be colored in any color There has been a need for a resin composition. In addition, there was a need for a material capable of marking a transparent resin with a laser, such as a relay case.However, there was no alternative but to irradiate a high-output carbon dioxide laser beam to an acrylic resin, and improvements were also required. .

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies in view of such a situation, and as a result, have found that a non-crystalline thermoplastic resin composition containing cordierite and / or tetrasilicon mica is contained. The object was found to be capable of easily performing clear and highly visible white marking on the surface thereof by irradiation with a low-energy laser beam, and completed the present invention.

That is, the present invention is characterized in that the surface of an amorphous thermoplastic resin composition containing cordierite and / or tetrasilicon mica is irradiated with a laser beam to perform marking. Laser marking method, amorphous thermoplastic resin, and 0.01 in the composition
An object of the present invention is to provide a resin composition for laser marking characterized by containing cordierite and / or tetrasilicon fluoride mica in an amount of up to 20% by weight .

As the non-crystalline thermoplastic resin used in the present invention, for example, acrylic resin, polystyrene resin,
Polycarbonate resin, polysulfone resin, polyphenylene ether resin, polyethersulfone resin, polyarylate resin, polyamideimide resin, polyetherimide resin, polymethylpentene resin, and the like. The resin may be mixed, and another resin may be mixed for the purpose of improving the physical properties.

The cordierite used in the present invention includes, in addition to the inorganic compound represented by the composition formula Mg ₂ Al ₄ Si ₅ O ₁₈ , Mg in which a part of Mg is replaced by Fe ²⁺ or water of 5% by weight or less. And the like.

[0009] fluorine four silicon mica, good preferable in that the marking can be in a more low-energy laser light.

These cordierite and tetrasilicon mica are used alone or in combination. The amount of the cordierite is usually a non-crystalline thermoplastic resin composition or a composition comprising this composition. For example, the content in a molded product or a film to be subjected to laser marking is in a range of 0.01 to 20% by weight. Above all, a range in which the content as a molded product or a coating is 0.1 to 10% by weight is preferable in that clear white marking with high visibility is obtained and physical properties are hardly deteriorated.

The laser used in the present invention is preferably a laser having a wavelength in the infrared region, and examples thereof include a carbon dioxide gas laser, a carbon monoxide laser, a semiconductor laser, and an yttrium aluminum garnet laser (YAG laser). Gas lasers are preferred.

As a carbon dioxide laser, for example, Transv
There are an ersely excited atomic pressure (TEA) type carbon dioxide laser, a scanning type (continuous oscillation or pulse oscillation) carbon dioxide laser, and the like.

[0013]

The resin composition for laser marking according to the present invention includes a molding composition and a coating composition such as a coating material comprising cordierite and / or tetrasilicic mica in an amorphous thermoplastic resin composition. And the like. Examples of the resin composition include, for example, a film formed by molding the molding material, a molded product such as an injection molded product or an extruded product, a coating obtained by coating the coating composition, and a dried coating. No.

[0015] Additives or solvents can be added to the resin used in the molding material and the coating composition, if necessary. As additives, dispersants (metal soaps, surfactants, etc.) suitable for the resins used, fluidity modifiers (metal soaps, bentonite, etc.), flame retardants (aluminum hydroxide, magnesium hydroxide, phosphate esters, etc.),
Lubricants / release agents (paraffin wax, polyethylene wax, etc.), antioxidants (naphthylamine, phenolic compounds, etc.), UV absorbers (salicylic acid derivatives,
Additives used in ordinary molding materials and coating compositions, such as benzophenone compounds, reinforcing agents (glass fibers, carbon fibers, etc.), coloring agents (inorganic pigments, organic pigments, etc.) are usually added. Appropriate amounts can be added.

In order to obtain the resin composition for laser marking of the present invention, a non-crystalline thermoplastic resin and 0.1% in the composition are used.
01 to 20% by weight of cordierite and / or fluorine
It is only necessary to uniformly mix the silicon mica and, if necessary, additives, solvents and the like by an arbitrary method, and the method is not particularly limited.

As a method of laser marking, for example, a method of scanning the surface of an article with a laser beam as a spot of an appropriate size, a method of forming a desired mark shape with a mask using a rectangular laser beam such as a TEA type carbon dioxide laser. Examples of the method include cutting and irradiating the surface of the article.

In order to carry out the laser marking method of the present invention, it is necessary to use an amorphous thermoplastic resin composition containing cordierite and / or tetrafluorosilicic mica as all or a part of the organic material portion of the product. A method of coating the surface of an object with the resin composition, applying a part of the surface of the object with the resin composition or forming a multilayer, or tapering the resin composition to adhere to the surface of an article. By forming the surface of the portion desired to be marked with the resin composition, it is only necessary to irradiate this with laser light to perform marking, and it is possible to form white marking with high sensitivity and high visibility only by this laser light irradiation. .

Examples of objects to be marked by the laser marking method of the present invention include electronic components such as capacitors and ICs; electrical components such as connectors, relay cases and printed circuit boards; gears, rotating shafts, support shafts, cams and the like. Mechanical parts; Wires, key tops, sheets, electrical product housings, cameras, cash vouchers, lenses, cards, etc., products that are normally marked;
Examples of such articles include very small articles that need to be marked with high accuracy.

[0020]

Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. All parts in the examples are on a weight basis.

Example 1 96 parts of polycarbonate resin [Panlite LN1250 manufactured by Teijin Chemicals Ltd.] 3 parts Cordierite (particle size: 325 mesh or less) 3 parts Petroleum handle 1 part After mixing these, using a twin screw extruder. The mixture was kneaded to obtain pellets for injection molding. Then, 2.6 cm thick and 9 cm x 5 cm by an in-line injection molding machine.
A 6 mm two-stage red-brown test piece was obtained.

Using a TEA-carbon dioxide laser, the molded article was irradiated with an irradiation energy of 4.9 joules / cm ² (hereinafter, referred to as “irradiation energy”).
(J / cm ² ) was irradiated for about 3 μs, and a clear white mark was obtained. When this mark was measured with a colorimeter, the L value representing whiteness was 50%.
Met.

Comparative Example 1 A red-brown test piece was obtained in the same manner as in Example 1 except that cordierite was removed, and then a laser beam was irradiated in the same manner, but no white mark was obtained. Further, when the L value was measured in the same manner as in Example 1, it was 20 as in the non-irradiated portion of the laser beam.

[0024] Example 2及 beauty Comparative Examples 2-4 Polycarbonate resin 98.9 parts [by GE Plastics Japan Ltd. Lexan 141] inorganic materials shown in Table 1 (however, the addition-free Comparative Example 2) 1 part of a black dye 0.1 parts [PS Black ME-1 manufactured by Mitsui Toatsu Dye Co., Ltd.] A black test piece was obtained in the same manner as in Example 1 except that these were used, and then irradiation energy was 4.9 J / cm ² and 5 .
Laser light of 7 J / cm ² was applied to different places, and the L value was measured with a colorimeter in the same manner as in Example 1. The results are shown in Table 1.

Table 1 ┌─────┬─────────┬─────────────────┐ │ │ │ L value │ │ │ material fee ^{├────────┬────────┤ │ │ │4.9J / cm 2 │5.7J} / cm 2 │ ├─────┼───── ────┼────────┼────────┤ │ Example 2 │ Fluorine tetrasilicic mica │ 41 │ 48 │ │ │ Comparative Example 2 │ No addition │ 4 │ 4 │ │ Comparative Example 3 │ Kaolin │ 18 │ 25 │ │ Comparative Example 4 │ Silica │ 4 │ 4 │ └─────┴─────────┴────────┴────────┘

[0026]

[0027]

Example 3 99 parts of acrylic resin 1 part of tetrasilicon mica (particle size 325 mesh or less) 1 part 0.05 parts of carbon black A black test piece was obtained in the same manner as in Example 1 except that these were used. When a laser beam was irradiated in the same manner, a clear white mark was obtained. When this mark portion was measured with a colorimeter, the L value representing whiteness was 48.

COMPARATIVE EXAMPLE 5 A black test piece was obtained in the same manner as in Example 3 except that tetrafluorosilicic mica was omitted. Then, when laser irradiation was performed in the same manner, no clear marking was obtained, and the L value was 24. Met. Further, another place was irradiated with a laser beam having an irradiation energy of 5.7 J / cm ² , but the L value was as low as 27 and clear marking could not be performed.

[0030]

[0031]

[0032]

In the discrimination based on the L value used in the above Examples and Comparative Examples, if the L value is less than 10, no discrimination is possible.
10 to 30 can be identified but is unclear, and a clear marking is obtained at 30 or more.

[0034]

By irradiating the surface of an article made of the resin composition for laser marking of the present invention with a laser beam, it is possible to easily display a white mark with high sensitivity and high visibility.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-226554 (JP, A) JP-A-63-20336 (JP, A) JP-A-3-272846 (JP, A) JP-A 61-226846 12748 (JP, A) JP-A-60-23159 (JP, A) JP-A-54-66957 (JP, A) JP-A-60-110737 (JP, A) (58) Fields investigated (Int. ⁶ , DB name) B41M 5/26 C09D 1/00-201/10

Claims (6)

(57) [Claims] 1. A surface of an article made of an amorphous thermoplastic resin composition containing cordierite and / or tetrasilicon mica is irradiated with a laser beam for marking. Laser marking method. 2. The method according to claim 1, wherein the thermoplastic resin composition contains tetrafluorosilicic mica. 3. A thermoplastic resin composition The method of claim 2, wherein one comprising polycarbonate resin or acrylic resins. 4. A thermoplastic resin composition having a cordierite and / or tetrafluorosilicic mica content of 0.0
4. The method according to claim 1, wherein the amount is 1 to 20% by weight. 5. A non-crystalline thermoplastic resin , comprising:
0.01-20% by weight of cordierite and / or fluorine
What is claimed is: 1. A resin composition for laser marking, comprising: tetrasilicon mica. 6. The resin composition according to claim 5, which comprises tetrafluorosilicic mica.