JPH09302236A - Resin composition capable of being color marked by laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a resin compsn. which can be color marked by laser beam irradiation by adding a colorless, color-developable component and a component, which, upon exposure to a laser beam, is decomposable to create color development of the color-developable component, to a thermoplastic polymer and kneading the mixture. SOLUTION: A thermoplastic polymer (a), such as polyethylene, polypropylene, or polystyrene, is mixed with a substantially colorless, color-developable component (b), such as a leuco compd., in an amt. of 0.1 to 30 pts.wt. based on the resin compsn., and a component (c) decomposable, upon exposure to laser beam, to create color development of the component (b), such as an arom. halogenated product or a sulfonic ester, in an amt. of 0.1 to 30 pts.wt. based on the resin compsn., and the mixture is melt-kneaded to obtain a resin compsn. which can be color marked by laser beam irradiation.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin composition capable of color marking by irradiation with laser light.

[0002]

2. Description of the Related Art Conventionally, as a marking method on the surface of a resin molded product, printing using an ink has been mainly carried out, but recently, a laser beam has been attracting attention because marking can be performed easily and efficiently. There is.

For example, JP-A-57-116620 and JP-A-6-48042 describe that it is possible to mark black on a white background or white on a black background by adding an appropriate additive to a resin. ing.

On the other hand, regarding color marking, Japanese Patent Laid-Open No. 60-155493 discloses that by using yellow iron oxide as an additive, it is possible to make red marking on a yellow background. However, in this case, the color is limited, which is a practical problem.

Further, JP-A-7-165979 and JP-A-7-278446 disclose that color marking can be performed on a dark background by using a colorant and carbon black or ivory black.

In Japanese Patent Application Laid-Open No. 2-4584, an azo dye or an introdan dye is used in combination with another dye, and only the azo dye or the introdan dye is selectively decomposed and bleached by a laser beam to form a dark background. It is reported that color marking is possible.

However, there is a problem that these color markings are limited to a dark background and their contrast is insufficient.

On the other hand, in the field of recording materials, it is well known that a color laser marking material is obtained by casting various color developing agents and color developing agents on a polymer, but this method is complicated to manufacture. , No superiority to printing is recognized.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides a resin composition capable of irradiating a laser beam and making a bright and colored marking on a light-colored background by melt-kneading an additive with a thermoplastic resin. It is in.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a specific color-forming dye in a polymer compound and a specific compound that decomposes by a laser beam to develop the dye. It has been found that by adding and, it is possible to perform bright colored laser marking on a light colored background.

That is, the present invention relates to (a) a thermoplastic polymer,
A resin composition capable of color laser marking, which comprises (b) a substantially colorless color-forming component and (c) a component that decomposes by laser light to develop the component (b).

The component (a) in the present invention is a thermoplastic polymer such as polyethylene, polypropylene, polystyrene, polyester, polyamide, polyvinyl chloride, ABS resin, polycarbonate, polymethylmethacrylate, polyoxymethylene, polyphenylene oxide, polyphenylene. Examples thereof include sulfide, polyether ester, polysulfone, polyketone, and ionomer. It is also possible to use a mixture of these polymers.

The color-forming component (b) in the present invention is a color-forming compound which is colorless before the color is formed and is colored by a specific stimulus. In particular, leuco dyes can be mentioned. Examples of particularly preferable leuco dyes include leuco crystal violet and leuco malachite green.

The amount of the color-forming component (b) added is 0.1 to 30% by weight, preferably 1 to 1 based on the resin composition.
0% by weight.

The component (c) in the present invention is a compound that decomposes upon irradiation with laser light to develop the color of the component (b). Further, the component (c) is a compound which is stable without being decomposed during melt-kneading, while it is rapidly decomposed by irradiation with laser light to develop the color of the component (b).
Examples of the component (c) include aromatic halides and sulfonic acid esters.

Examples of the aromatic halide include bromobenzene and dibromobenzene.
In addition, examples of the sulfonic acid ester include methyl p-toluenesulfonate and methyl benzenesulfonate.

As the component (c) such as aromatic halide or sulfonate, one kind may be used, or two or more kinds may be used in combination.

The amount of component (c) added is 0.1 to 30% by weight, preferably 1 to 15% by weight, based on the resin composition.

Other components may be added to the resin composition of the present invention as long as the laser marking characteristics are not impaired. In particular, it is preferable to add a sensitizer for laser light. Further, glass fiber or the like may be added to maintain the mechanical strength of the resin composition. Other components include inorganic compounds such as antioxidants, flame retardants, release agents, and citrus agents.

The resin composition of the present invention can be manufactured by a conventional method. For example (a) a thermoplastic polymer,
It can be produced by melt-mixing (b) the color-forming component and (c) the component that decomposes with laser light to develop the (b) component using a kneading extruder. Alternatively, the component (a) and the component (b), the component (a) and the component (c) may be mixed by a kneading extruder, and they may be mixed at the time of molding.

The resin composition of the present invention can be color-marked by irradiating it with a laser beam after molding. The laser light source is not particularly limited, but carbon dioxide gas laser, YAG laser, argon laser, helium-neon laser, various excimer lasers,
Various semiconductor lasers and the like can be exemplified. A carbon dioxide gas laser is preferred.

[0022]

INDUSTRIAL APPLICABILITY In the resin composition capable of color laser marking of the present invention, the irradiated portion is colored by irradiating with a laser beam and marking can be performed with good contrast. Also, by selecting the color-forming component, any color can be added. Such a resin composition can be easily produced by using a conventional melt-kneading method and has excellent productivity.

The resin composition can be used by molding into a film, a fiber or various molded products by, for example, injection molding or extrusion molding.

Therefore, it can be used for applications in which writing is performed by printing, for example, marking of a keyboard top, a housing, and individual members. These molded articles can be colored with a laser beam without any problem.

[0025]

The present invention will be described in detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

In the examples, "part" means "part by weight".

[Example 1] 265 parts of ABS resin (ST30B manufactured by Mitsui Toatsu Chemicals, Inc.), 15 parts of leuco crystal violet, 30 parts of p-dibromobenzene were used.
mmΦ 2-axis extruder (PC made by Ikegai Tekko Co., Ltd.
M-30) under nitrogen stream and polymer temperature 230
The mixture was melt-kneaded under the conditions of ℃ and average residence time of 3 minutes and pelletized.

Next, an injection molding machine (manufactured by Meiki Seisakusho Co., Ltd.)
M-50B) was used for injection molding at a cylinder temperature of 230 ° C. and a mold temperature of 60 ° C. to obtain a 2 mm thick white (light blue) sample (test piece).

On the other hand, a carbon dioxide laser (laser mark 940 Cool Flow CFT manufactured by Lumonix Co., Ltd.)
By irradiating a laser beam with -75), a bright blue symbol could be given.

[Example 2] 265 parts of ABS resin (ST30B manufactured by Mitsui Toatsu Chemicals, Inc.), 15 parts of leucomalachite green, 30 parts of p-dibromobenzene 30 mm
Φ2-axis extruder (made by Ikegai Tekko Co., Ltd. PCM-
30), a polymer temperature of 230 ° C. under a nitrogen stream,
The mixture was melt-kneaded under the conditions of an average residence time of 3 minutes and pelletized.

Next, an injection molding machine (manufactured by Meiki Seisakusho Co., Ltd.)
M-50B) was used for injection molding at a cylinder temperature of 230 ° C. and a mold temperature of 60 ° C. to obtain a 2 mm thick white (light green) sample (test piece).

On the other hand, carbon dioxide laser (Lumonics Co., Ltd. laser mark 940 Cool Flow CFT)
By irradiating a laser beam with -75), a bright green symbol could be given.

Example 3 265 parts of polystyrene (Denkastyrol manufactured by Denki Kagaku Kogyo Co., Ltd.), 15 parts of leuco crystal violet, 30 parts of methyl p-toluenesulfonate were added to a 30 mmΦ biaxial extruder (PCM manufactured by Ikegai Tekko KK). -30) was melt-kneaded under a nitrogen stream under the conditions of a polymer temperature of 220 ° C. and an average residence time of 3 minutes, and pelletized.

Next, an injection molding machine (manufactured by Meiki Seisakusho Co., Ltd.)
M-50B) was used to perform injection molding at a cylinder temperature of 220 ° C. and a mold temperature of 60 ° C. to obtain a 2 mm thick pale yellow sample (test piece).

On the other hand, a carbon dioxide laser (laser mark 940 Cool Flow CFT manufactured by Lumonix Co., Ltd.)
By irradiating a laser beam with -75), a bright blue symbol could be given.

Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08K 5/00 KAJ C08K 5/03 KAL 5/03 KAL 5/42 KBU 5/42 KBU C08L 55/02 LMC C08L 55/02 LMC B41M 5/18 Q

Claims (4)

[Claims] 1. A color laser-markable resin composition comprising (a) a thermoplastic polymer, (b) a substantially colorless color-forming component, and (c) a component that decomposes by laser light to develop the component (b). . 2. The color laser-markable resin composition according to claim 1, wherein the color-forming component (b) is a leuco compound. 3. The color laser-markable resin composition according to claim 1, wherein the component (c) which decomposes by laser light to develop the color of the component (b) is an aromatic halide or a sulfonic acid ester. 4. A resin composition comprising (a) a thermoplastic polymer, (b) a leuco compound, and (c) an aromatic halide or a sulfonic acid ester, wherein the component (b) is 0. 1 to 30 parts by weight, and the component (c) is 0.1 to 30 parts by weight with respect to the resin composition, which is capable of color laser marking.