JPH0867068A - Composition for laser marking - Google Patents

Abstract

PURPOSE: To provide a composition for laser marking which shows a color tone change to a color group suited for laser marking which can be easily precision-finished and is advantageous oostwise, instead of printing when a character, a symbol, a linear image or a pattern is printed on an outer surface in order to explain the identification mark or part function of a finished product. CONSTITUTION: This composition for laser marking contains at least, (a) thermoplastic resin or thermosetting resin, and (b) an inorganic color developing substance whose color tone changes by application of a laser beam. In addition, the component of (a) is 40 to 9% and the component of (b) is 1 to 60% as the combined weight standard of (a) and (b).

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 which can be marked with a laser beam.

[0002]

2. Description of the Related Art For example, in many fields such as electric equipment and machinery, electronic equipment and parts, characters and symbols, line drawings and patterns are formed on the outer surface of the outer surface for the purpose of identifying products and explaining the functions of parts. In carrying out the above, a laser marking method, which is easy to perform precision finishing instead of printing and is advantageous in terms of cost, has been attracting attention in recent years and various proposals have been made. For example, for a fluororesin coating compounded with aluminum oxide or titanium oxide,
A method of marking using a color change (white → black) due to a change in the oxidation number of aluminum oxide or titanium oxide when irradiated with laser light (JP-A-6-100716), and carbon black and / or graphite in a polyester resin A method of irradiating a composition mixed therein with laser light to change the color tone (black → white or black → gray) and marking is known (Japanese Patent Laid-Open No. 4-2464).
56).

[0003]

However, in any of these cases, there is a monotonous change in color tone in black / white or gray, and the change in color tone is not necessarily large, so that a marking with clear and large contrast is obtained. There is a strong demand for improvements such as the difficulty in making the product, and the restriction of the so-called color design development.

[0004]

The inventors of the present invention have long urged various studies to solve the above-mentioned problems, and as a result, mainly composed of titanium dioxide containing various metal elements. When an inorganic color-forming substance is applied to laser marking, the white or light-colored compounding composition can be colored to a desired color density in various hue systems by irradiation with laser light. Has a clear and sufficient contrast color design as a marking display,
The present invention has been completed based on the knowledge that various color design developments can be made.

That is, the present invention is as follows: (A) a thermoplastic resin or a thermosetting resin, and (b)
At least an inorganic color-forming substance capable of changing color tone by laser light irradiation, and (c) the components (a) and (b) have a component (a) of 4 as a total weight basis.
1. A composition for laser marking, wherein the composition is 0 to 99% and the component (b) is 1 to 60%. The component (b) is (d) NiO, Cr ₂ O ₃ , MnO, FeO, Fe ₂ O ₃ , Co.
At least one component selected from O, CuO, Li ₂ O, MgO, ZnO and Al ₂ O ₃ and (e) Sb ₂ O ₅ , Sb ₂ O ₃ , Nb ₂ O ₅ , WO ₃ and V ₂ O ₅ , Ta ₂
The composition for laser marking according to claim 1, which is a titanium dioxide-based color-forming substance containing at least one component selected from O ₅ and MoO ₃ . 3. In addition to the components (a) and (b), the total amount of the components (a) and (b) is 0.01 to 5% by weight.
2. The laser marking composition according to item 1 above, which further comprises the organic pigment or dye described above.

In the present specification, the case of the molding resin composition and the case of the coating resin coating liquid composition are collectively referred to as
It is called a composition for laser marking.

In the present invention, as the inorganic color-forming substance of the component (b), various substances capable of changing the color tone from white or light color system to dark color system by laser irradiation can be used. In particular, an unsintered product or a low-sintered product which is a precursor of a titanium dioxide-based colored calcined pigment containing various metal elements is suitable. It can be produced by various methods, for example TiCl ₄ , Ti
A soluble titanium source solution such as OSO ₄ or Ti ₂ SO ₄ is neutralized with an alkaline substance or hydrolyzed by heating to produce a hydrous titanium dioxide slurry, in which (d)
NiO, Cr ₂ O ₃ ,, MnO, FeO, Fe ₂ O ₃ ,, CoO, CuO, Li ₂ O, MgO, ZnO and
At least one component selected from Al ₂ O ₃ and (e) Sb ₂ O
_At least one component selected from ₅ , Sb ₂ O ₃ , Nb ₂ O ₅ , WO ₃ , V ₂ O ₅ , Ta ₂ O ₅ and MoO ₃ is added as a soluble salt in a predetermined amount, and if necessary, medium What was ground, filtered, washed, dried, and crushed can be used. In the above, instead of drying, baking at a low temperature that does not cause color development and crushing can be used more advantageously.

In the present invention, examples of the inorganic color-forming substance include TiO ₂ -Cr ₂ O ₃ -Sb ₂ O ₃ system (reddish yellow), TiO ₂ -C
r ₂ O ₃ -WO ₃ system, TiO ₂ -CoO-Sb ₂ O ₃ system, TiO ₂ -CoO-WO ₃ system (all are reddish yellow), TiO ₂ -Cr ₂ O ₃ -NiO-Sb ₂ O ₃ series, TiO ₂ -NiO-
WO ₃ system, TiO ₂ -NiO-Sb ₂ O ₃ system (all are yellow), TiO ₂ -MnO
-Sb ₂ O ₃ system (chocolate color), TiO ₂ -SnO ₂ -MgO-Sb ₂ O ₃ system,
TiO ₂ -SnO ₂ -ZnO-Sb ₂ O ₃ system (both are blue), TiO ₂ -SnO ₂ -N
Those having a composition such as iO—Sb ₂ O ₃ system and TiO ₂ —FeO—WO ₃ system (all are olive green) are particularly preferable. In the titanium dioxide-based color-forming substance containing the components (d) and (e), the addition ratios of the component (d) and the component (e) are the same as the components (d) and (e) added.
It is preferable that the total amount ratio (molar ratio) of the cations to the total anions of the components is approximately 1: 2 (d component: e component). Further, in order to develop a blue or green color, SnO ₂ is preferably added, and the addition amount is preferably about 5 to 30% by weight with respect to titanium dioxide.
Incidentally, the inorganic color-forming substance, various baking treatment agents and mineralizers used during the production of ordinary baking pigments, such as Li ₂ O, Na ₂ O, K ₂ O, P ₂ O ₅ etc. By adding the above component, the color developability by laser light can be made more desirable. Further, the color-forming substance has an inorganic surface modifier, for example, an oxide or a hydrous oxide such as Al, Si, or Zr on its surface, or a polyol-based, siloxane-based, amine-based, or other organic treatment agent. By performing the surface treatment, the dispersibility and the like can be made more preferable without impairing the coloring characteristics of the laser beam.

In the present invention, as the component (a), various thermoplastic or thermosetting resins can be used. For example, polyamide, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, modified polyphenylene oxide, modified General engineering plastics such as polyphenylene ether, polyether sulfone, polysulfone, polyether ketone, polyphenylene sulfide, polyarylate, polyamide bismaleimide, polyether imide, polyimide, special engineering plastics such as fluororesin, polyethylene, polypropylene General-purpose thermoplastic resins such as polystyrene, polystyrene, AS resin, ABS resin, epoxy resin, unsaturated polyester resin, phenol resin Melamine resins, silicone resins, amino resins, vinyl resins, can be used thermosetting resins such as acrylic resins, polyurethane resins, alkyd resins. Therefore, the ratio of the component (a) and the component (b) is 40 to 90% for the component (a) and 1 for the component (b) based on the total weight of the components (a) and (b).
~ 60%. In the above, in the case of a thermoplastic molding resin composition system, the proportion of the component (b) is used in a relatively low content region of the above range, while a thermosetting coating resin composition system is used. In this case, the ratio of the component (b) is used in the relatively high content range of the above range. In the above description, if the ratio of the component (b) is too lower than the above range, marking with desired contrast cannot be achieved, and if the ratio of the component (b) is too higher than the range, laser marking is performed. The protective properties (tensile strength, impact strength, elongation, etc.) and appearance (surface smoothness, gloss, etc.) of the resin composition or coating are likely to be impaired, which is not preferable.

In the present invention, in addition to the change in color tone due to the inorganic color-forming substance, an organic pigment or dye may also be used in combination to further enhance the contrast and make the marking distinguishability more suitable. . As the organic pigment or dye, it is preferable to select and use a hue-based one having a complementary color relationship with the coloring of the inorganic color-forming substance by laser light. For example, when the inorganic color-forming substance is composed of TiO ₂ -Cr ₂ O ₃ -Sb ₂ O ₃ system, the color after coloring exhibits a reddish yellow color. , The laser non-irradiated portion is blue-violet type, while the laser-irradiated portion is reddish yellow, the contrast is stronger, and it becomes easier to identify characters, line drawings, figures, patterns and the like.
As the organic pigment or dye, various ones may be used, for example, azo-based, phthalocyanine-based, quinacridone-based, isoindolinone-based, isoindoline-based, dioxazine-based, threne-based, perylene-based, perinone-based, thioindigo-based Examples thereof include pigments such as tinophthalone type and metal complex type, and dyes such as azo type, anthraquinone type, indigo type, phthalocyanine type, carbonyl type, quinone imine type, methine type, quinoline type and nitro type dyes. The amounts of the organic pigments and dyes used are (a) component and (b)
It is preferably about 0.01 to 5% based on the total weight of the components. If the amount used is less than the above range, coloring of the non-irradiated portion with laser light becomes insufficient, and if the amount used exceeds too much, it is not economical and erasing after laser light irradiation becomes insufficient, which is not preferable.

Various kinds of laser light can be applied to the laser marking composition of the present invention, and examples thereof include YAG laser, CO ₂ laser, ArF laser, and XeCl excimer laser. As the wavelength of the laser light, it can be used over various ranges, but in order to efficiently change the color tone of the inorganic color-forming substance of the component (b) and perform the marking optimally, it is possible to use 300 to 400 nm in particular. Area is preferred. The intensity (irradiation energy density of laser light) can be used in various ranges, but it is 1 to 10 mJ / ns.
-It is preferably about cm ² .

[0012]

【Example】

Example 1 1000 ml of a hydrous titanium oxide slurry (TiO ₂ 200 g / l) obtained by heating and hydrolyzing a titanyl sulfuric acid solution was placed in a 2 l beaker, and 180 ml of an aqueous chromium sulfate solution (Cr ₂ O ₃ 100 g /
l) was added, and subsequently 400 g of Sb ₂ O ₃ powder was added, and then neutralized to pH 7 with aqueous ammonia, followed by filtration and washing. The obtained cake was fired at 400 ° C. for 1 hour in an electric furnace, and then pulverized with an air flow type pulverizer to obtain a powder A having a light green color. Using this, a resin composition was prepared with the following composition, and this composition was molded into a plate by a conventional method. Polyethylene terephthalate resin 100 parts by weight Powder A 5 parts by weight A molded product was exposed to a mask with a XeCl (308 nm) excimer laser with an energy density of 5 mJ / ns · cm ² and a pulse width of 20 n.
100 pulses were irradiated as s. The irradiation part is reddish yellow,
A clear marking with light green in the unirradiated area was obtained.

Example 2 Using the powder A obtained in Example 1 and a blue color dye (phthalocyanine type), molding was carried out in the same manner as in the same example to obtain a polyethylene terephthalate plate. When this plate was irradiated with laser in the same manner as in Example 1,
A clear marking was obtained in which the irradiated part was reddish yellow and the unirradiated part was blue.

[0014]

The composition for laser marking of the present invention comprises:
It enables unprecedented marking such as chromatic coloring of the laser irradiation part, which is useful for color diversification, etc. Also, when used in combination with complementary color organic pigments and dyes, the contrast is large and the distinction is easy and colorful. Enables easy laser marking.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08K 3/22 KAE C08L 101/00 KAE

Claims (3)

[Claims] 1. At least containing (a) a thermoplastic resin or a thermosetting resin, and (b) an inorganic color-forming substance capable of changing a color tone by laser light irradiation, and (c) the (a) above.
And (b) are 40 to 99% of the component (a) and 1 to 60% of the component (b), based on the total weight thereof, and a composition for laser marking. 2. The component (b) is (d) NiO, Cr ₂ O ₃ , MnO, Fe.
At least one component selected from O, Fe ₂ O ₃ , CoO, CuO, Li ₂ O, MgO, ZnO and Al ₂ O ₃ and (e) Sb ₂ O ₅ , Sb ₂ O ₃ , Nb ₂ O ₅ , WO
_2. The laser according to claim 1, wherein the laser is a titanium dioxide-based color-forming substance containing at least one component selected from ₃ , V ₂ O ₅ , Ta ₂ O ₅ and MoO _3. Marking composition. 3. In addition to the component (a) and the component (b),
Based on the total weight of the components (a) and (b),
The composition for laser marking according to claim 1, which further comprises 0.01 to 5% of an organic pigment or dye.