JP7178239B2 - Composition for laser marking, method for producing the same, and molding for laser marking - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laser-printing composition, a method for producing the same, and a laser-printing molding produced using the composition.

A method is known in which characters, symbols, patterns, etc. are printed by irradiating a molded article with a laser to cause it to develop a color. Specifically, there is a technique for developing white, black, or a single color other than white and black by laser irradiation (see, for example, Patent Document 1), or creating a coloring layer on the surface of a molded body and irradiating the coloring layer with a laser. There is known a technique for developing color by heating (see, for example, Patent Document 2).

JP 2006-083242 A Japanese Patent Publication No. 2016-539031

However, in the conventional printing method, heat is generated in the kneading process and the molding process of the composition for forming the molded article, and the heat causes the color former to react and color the composition itself. . For this reason, in order to suppress coloration due to heat, it was necessary to devise a molded article such as providing a coloring layer separately on the surface of the molded article as in the technique disclosed in Patent Document 2.

In addition, in conventional laser-printing moldings, the laser coloring agent bleeds out in the printed area where a chromatic color is developed by laser irradiation, and other materials come into contact with the printed area, resulting in color transfer to other materials. I had something to do. Therefore, it is necessary to suppress the bleeding out of the laser color former in the printed portion formed on the molded article for laser printing.

Therefore, some aspects of the present invention provide a molding that does not develop color even after a kneading step or a molding step, has a function of being able to develop a chromatic color by laser irradiation, and can suppress bleeding out of the laser color former. A laser marking composition is provided for easily creating a body.

The present invention has been made to solve at least part of the above problems, and can be implemented as any of the following aspects.

One aspect of the composition for laser printing according to the present invention is
a polymer (A);
at least one laser coloring agent (B) selected from the group consisting of a laser coloring agent (B1) containing a compound having a lactone skeleton and a laser coloring agent (B2) containing a compound having a triarylmethane skeleton;
a compound (C) having a first acid dissociation constant (pKa) of 9 or more;
contains
0.05 parts by mass or more and 25 parts by mass or less of the laser coloring agent (B) is contained with respect to 100 parts by mass of the polymer (A).

In one aspect of the laser marking composition,
0.0001 parts by mass or more and 1 part by mass or less of the compound (C) can be contained with respect to 100 parts by mass of the polymer (A).

In any embodiment of the laser marking composition,
When the compound (C) does not contain a salt,
When the content of the laser color former (B) is M _B (parts by mass) and the content of the compound (C) is M _C (parts by mass), M _C /M _B is 0.001 to 0.001. can be one.

In any embodiment of the laser marking composition,
When the compound (C) contains a salt,
When the content of the laser color former (B) is M _B (parts by mass) and the content of the compound (C) is M _C (parts by mass), M _C /M _B is 0.005 to 10. can be.

In any embodiment of the laser marking composition,
The compound having a lactone skeleton can be a compound having a fluorane skeleton.

In any embodiment of the laser marking composition,
The compound (C) is at least one compound selected from the group consisting of metal hydroxides, organic ammonium salts, organic potassium salts, amines and ammonia having a primary acid dissociation constant (pKa) of 9 or more. be able to.

In any embodiment of the laser marking composition,
The compound (C) may be at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonia, ammonium acetate, potassium acetate, ammonium formate and potassium formate.

In any embodiment of the laser marking composition,
Furthermore, at least one compound selected from the group consisting of lanthanum hexaboride, tungsten cesium oxide, indium tin oxide (ITO) and antimony tin oxide can be contained.

In any embodiment of the laser marking composition,
Furthermore, it can contain an organic halide.

One aspect of the molded article for laser printing according to the present invention is
It is prepared using the laser marking composition according to any one of the above embodiments.

One aspect of the method for producing a composition for laser printing according to the present invention is
After mixing the laser coloring agent (B) and the compound (C) having a first acid dissociation constant (pKa) of 9 or more, the method comprises a step of mixing them with the polymer (A).

According to one aspect of the composition for laser printing according to the present invention, the laser coloring agent in the printed portion does not develop color even after the kneading process and the molding process, and has a function capable of developing a chromatic color by laser irradiation. It is possible to easily prepare a molded body for laser printing that can suppress the bleeding out of. Further, according to one aspect of the composition for laser marking according to the present invention, there is no need to provide a separate coloring layer on the surface of the molded body in order to impart a function capable of developing a chromatic color. The above function can be imparted to the molded product.

It is a conceptual diagram for demonstrating an example of the laser marking method. It is a conceptual diagram for demonstrating an example of the laser marking method.

Preferred embodiments of the present invention are described in detail below. In addition, the present invention is not limited to the following embodiments, and includes various modifications implemented without changing the gist of the present invention.

In the present specification, a numerical range described using "to" means that the numerical values described before and after "to" are included as lower and upper limits.

In the present invention, "laser printing" refers to the development of chromatic colors by laser irradiation, and may include the development of one or more chromatic colors and the further development of achromatic colors.

As used herein, the term “chromatic color” refers to a color having three dimensions of hue, lightness, and saturation, such as red, blue, yellow, green, purple, and blue-green. As used herein, the term "achromatic color" refers to a color that includes only the lightness dimension, such as white, gray, and black.

1. Laser-printing composition The laser-printing composition according to the present embodiment comprises a polymer (A), a laser color former containing a compound having a lactone skeleton (B1), and a laser color former containing a compound having a triarylmethane skeleton. It contains at least one laser coloring agent (B) selected from the group consisting of (B2) and a compound having a first acid dissociation constant (pKa) of 9 or more. The laser marking composition according to this embodiment will be described in detail below.

1.1. Polymer (A)
The composition for laser printing according to this embodiment contains the polymer (A). The polymer (A) functions as a base material for a molded article obtained by molding the composition.

As the polymer (A), known materials can be used, for example, polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polycarbonate ( polyester polymers such as PC); acrylic polymers such as polymethyl methacrylate (PMMA); polyacetal (POM) polymers; polyolefins such as polyethylene (PE) and polypropylene (PP); can be used. Among these, it is one type of polymer selected from the group consisting of polymethyl methacrylate, polyacetal-based polymers, polyethylene and polystyrene, since a transparent or white opaque molded article having excellent mechanical strength can be obtained. is preferred. Clear printing of chromatic colors and achromatic colors becomes possible by forming a transparent or white opaque molded body.

1.2. Laser coloring agent (B)
The composition for laser printing according to the present embodiment includes at least one selected from the group consisting of a laser coloring agent (B1) containing a compound having a lactone skeleton and a laser coloring agent (B2) containing a compound having a triarylmethane skeleton. and a laser coloring agent (B).

A leuco dye is preferable as the laser color former (B). As used herein, the term “leuco dye” refers to a compound having a function of coloring when irradiated with a laser.

The lower limit of the content of the laser color former (B) is 0.05 parts by mass, preferably 0.1 parts by mass, more preferably 0.1 part by mass, per 100 parts by mass of the polymer (A). 2 parts by mass, particularly preferably 0.3 parts by mass. The upper limit of the content of the laser color former (B) is 25 parts by mass, preferably 10 parts by mass, and more preferably 5 parts by mass. When the content of the laser color former (B) is within the above range, the molded article can be imparted with a function capable of developing a chromatic color by laser irradiation, and the laser color former (B) in the printed part of the resulting molded article ) can be suppressed.

1.2.1. Laser coloring agent (B1)
The laser color former (B1) contains a compound having a lactone skeleton. A compound having a lactone skeleton develops color when a lactone ring in the molecule is opened by laser irradiation. Among such compounds having a lactone skeleton, compounds having a fluoran skeleton are preferred.

As commercial products of compounds having a lactone skeleton, RED40, BLUE63 (manufactured by Yamamoto Kasei Co., Ltd.), RED500, CVL, LCV-L, BLACK305 (manufactured by Yamada Kagaku Kogyo Co., Ltd.) and the like can be preferably used. can.

The content of the laser color former (B1) is preferably 0.1 parts by mass or more and 25 parts by mass or less, and is preferably 0.2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymer (A). more preferably 0.3 parts by mass or more and 5 parts by mass or less.

1.2.2. Laser coloring agent (B2)
The laser coloring agent (B2) contains a compound having a triarylmethane skeleton. Compounds having a triarylmethane skeleton include 4,4′-tetramethyldiaminotriphenylmethane and tris(4-dimethylaminophenyl)methane.

As commercial products of compounds having a triarylmethane skeleton, Leuco Malachite Green (manufactured by Tokyo Chemical Industry Co., Ltd.), Leuco Crystal Violet (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), and the like can be preferably used.

The content of the laser color former (B2) is preferably 0.1 parts by mass or more and 25 parts by mass or less, and is preferably 0.2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymer (A). more preferably 0.3 parts by mass or more and 5 parts by mass or less.

1.3. Compound (C) having a first acid dissociation constant (pKa) of 9 or more
The composition for laser printing according to the present embodiment includes a compound (C) having a first acid dissociation constant (pKa) of 9 or more (herein, also simply referred to as "compound (C)" or "component (C)"). ). By containing the compound (C) having a first acid dissociation constant (pKa) of 9 or more in the laser marking composition according to the present embodiment, coloration can be effectively suppressed even through the kneading process and the molding process. There was found.

The first acid dissociation constant (pKa) in component (C) is a value when water at 25° C. is used as a solvent, and is described, for example, in (a) The Journal of Physical Chemistry vol. 68, number 6, page 1560 (1964); Chemical Handbook (revised 3rd edition, June 25, 1984, published by Maruzen Co., Ltd.), (d) databases such as pKaBASE manufactured by Compudrug, etc. can be used. can. The first acid dissociation constant (pKa) in a compound ionizing in multiple stages means the pKa value in the first stage of ionization.

Component (C) is not particularly limited as long as it is a compound having a primary acid dissociation constant (pKa) of 9 or more, and is selected from the group consisting of metal hydroxides, organic ammonium salts, organic potassium salts, amines and ammonia. is preferably at least one compound that is

Specific examples of component (C) include metal hydroxides such as sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide; organic ammoniums such as tetramethylammonium hydroxide (TMAH), ammonium acetate, and ammonium formate; Salts; organic potassium salts such as potassium acetate and potassium formate; monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-methyl-N,N-diethanolamine, N,N-dimethylethanolamine, N,N - diethylethanolamine, N,N-dibutylethanolamine, N-(β-aminoethyl)ethanolamine, N-ethylethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, monoisopropanolamine, diisopropanolamine, alkanolamines such as triisopropanolamine; primary amines such as methylamine, ethylamine, propylamine, butylamine, pentylamine and 1,3-propanediamine; secondary amines such as piperidine and piperazine; Tertiary amines; besides ammonia, potassium iodide, sodium thiosulfate, iron oxide, tin chloride, sodium cyanoborohydride, lithium borohydride, sodium borohydride and the like can be mentioned. These (C) components may be used individually by 1 type, and may be used in mixture of 2 or more types.

Among these components (C), at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonia, ammonium acetate, potassium acetate, ammonium formate and potassium formate is more preferred.

The lower limit of the content ratio of component (C) is preferably 0.0001 parts by mass, more preferably 0.001 parts by mass, and even more preferably 0, relative to 100 parts by mass of the polymer (A). 0.003 parts by weight, particularly preferably 0.005 parts by weight. The upper limit of the content ratio of component (C) is preferably 1 part by mass, more preferably 0.7 parts by mass, and particularly preferably 0.5 parts by mass with respect to 100 parts by mass of the polymer (A). part by mass. When the content of the component (C) is within the above range, it is possible to more effectively suppress the coloring of the composition and the molded article even after the kneading process and the molding process.

The preferable content ratio of component (C) to the laser color former (B) differs depending on whether component (C) contains salt or does not contain salt.

The content of component (C) in the case where component (C) does not contain a salt is M _B (parts by mass) for the content of the laser color former (B) and M _C (parts by mass) for the content of the compound (C). ), the value of M _C /M _B is preferably 0.001 to 0.1, more preferably 0.003 to 0.05. When the component (C) does not contain a salt, if M _C /M _B is within the above range, the composition and the molded article can be more effectively prevented from being colored even after the kneading step and the molding step.

When the component (C) contains a salt, the content of the component (C) is M _B (parts by mass) for the content of the laser coloring agent (B) and M _C (parts by mass) for the content of the compound (C). , the value of M _C /M _B is preferably 0.005 to 10, more preferably 0.01 to 5. When the component (C) does not contain a salt, if M _C /M _B is within the above range, the composition or the molded article can be more effectively prevented from being colored even after the kneading process and the molding process, and the molded article can be Weather resistance can be further improved.

1.4. Other Additives The laser-printing composition according to the present embodiment may contain other additives in addition to the components described above, depending on the purpose and application. Other additives include, for example, color developers and fillers.

1.4.1. Color developer The color developer has a function of acting on the laser color former (B1) or the laser color former (B2) by laser irradiation to develop color when printing by laser irradiation. Organic halides are preferably used as color developers. Examples of organic halides include dibromobenzene, hexabromobenzene, pentabromotoluene, pentabromodiphenyl ether, dichlorobenzene, hexachlorobenzene and the like. These color developers can be used singly or in combination of two or more.

The content of the developer is preferably 0.1 to 15 parts by mass, more preferably 0.2 to 12 parts by mass, per 100 parts by mass of the polymer (A).

1.4.2. Filler The filler has a function of converting electromagnetic radiation into heat during printing by laser irradiation, and mainly causing the laser coloring agent (B1) to develop color with heat. Such fillers include metal particles such as aluminum, nickel, gold, silver, copper, iron, stainless steel (SUS); titanium oxide, magnesium oxide, zinc oxide, aluminum oxide, silicon oxide, indium tin oxide (ITO). , antimony tin oxide, tungsten cesium oxide, and other metal oxide particles; carbon black, lanthanum hexaboride, and the like. Among these fillers, at least one compound selected from the group consisting of lanthanum hexaboride, tungsten cesium oxide, indium tin oxide (ITO) and antimony tin oxide is preferred. These fillers can be used singly or in combination of two or more.

The content of the filler is preferably 0.01 to 5 parts by mass, more preferably 0.03 to 3 parts by mass, and 0.05 to 1 part by mass with respect to 100 parts by mass of the polymer (A). Parts by mass are particularly preferred.

1.5. Method for producing a composition for laser printing The composition for laser printing according to the present embodiment can be produced, for example, by a method in which the raw material components described above are put into a Banbury mixer, a kneader, a roll, or the like, and kneaded. can. As a kneading method, each component may be added all at once, or may be kneaded in a multistage addition method.

According to the composition for laser marking according to the present embodiment, the composition and the molded article are not colored even after the kneading process and the molding process, and a molded article having a function capable of developing a chromatic color by laser irradiation can be produced. can be done.

2. Molded article for laser printing Pellets of the composition for laser printing are formed into a predetermined shape by injection molding, extrusion molding, hollow molding, compression molding, film extrusion, sheet extrusion, vacuum molding, foam molding, blow molding, or the like. Moldings for laser marking can be produced.

The shape of the molded body for laser marking can be selected from various shapes according to the purpose and application. It may be a surface or the like.

3. Printing Method By irradiating the molded body for laser printing obtained as described above with a laser beam, the laser-irradiated portion can be made to develop a chromatic color. That is, since the laser coloring agent (B) develops color by irradiation with a laser beam, printing becomes possible.

In general, the “energy” of laser light depends on the irradiation conditions of the laser light. Specifically, in addition to the type, wavelength, pulse width, frequency, and output of the laser light to be irradiated, the irradiation time, irradiation area, distance and angle from the light source to the laser-printing molding, irradiation method, etc. can be changed. Laser beams "having different energies" when irradiating two or more laser beams may be applied. For example, laser light with different wavelengths may be used to irradiate laser light with two different energies, or laser light with two different energies may be applied by changing the irradiation conditions for laser light with the same wavelength. may

As a laser light irradiation method, either a scanning method or a mask method may be used. In addition, two or more laser beams having different energies may be irradiated simultaneously, or may be irradiated one by one.

As a laser light irradiation device, a general laser printing device or the like can be used. At the time of laser marking, two or more laser beams having different energies may be irradiated with one device, or a plurality of devices may be used. As a device capable of laser printing, for example, a laser printing system "RSM50D type" or "RSM30D type" manufactured by Lofin Basel, a laser printing system "MDU1000C" manufactured by Keyence Corporation, or the like can be used.

In this specification, numbers indicating the "wavelength" of laser light, such as wavelength 1064 nm and wavelength 355 nm, mean the center wavelength and generally include an error of about ±3%.

A convenient way to obtain laser light with two or more different energies is to use laser light of different wavelengths. For example, when laser printing is performed by irradiating two or more laser beams having different wavelengths, the difference in wavelength between the laser beams is preferably 100 nm or more, more preferably 200 nm or more, and particularly preferably 500 nm or more. Incidentally, the upper limit is usually 1,500 nm.

The wavelength of the low-energy laser light used for developing the color of the laser color former (B1) is preferably 700 nm or more and 11000 nm or less, more preferably 800 nm or more and 1100 nm or less. As such a long-wavelength laser, a YAG laser, a _YVO4 near-infrared laser (wavelength: 1064 nm), a CO2 laser (wavelength: 10600 nm), or the like can generally be preferably used.

The wavelength of the high-energy laser light used for developing the color of the laser color former (B2) is preferably 300 nm or more and less than 700 nm, more preferably 350 nm or more and 600 nm or less. As such a short-wavelength laser, UV laser (wavelength: 355 nm), blue laser (wavelength: 455 nm), green laser (wavelength: 532 nm), etc. can generally be preferably used.

Specific examples of the printing method by laser light irradiation will be described below with reference to the drawings, but the printing method by laser light irradiation is not limited to these. A laser beam is irradiated onto the laser-printing molding 1 according to the present embodiment ([I] in FIG. 1). At this time, laser beams having two different energies may be irradiated. For example, when irradiating with lasers having two different energies, the laser light irradiation may be performed simultaneously or separately. Further, depending on the target color, the irradiation position may be different, or overlapping colors may be mixed. The portion irradiated with the low-energy laser light is printed in a color derived from the laser color former (B1) (3a in FIG. 1), while the portion irradiated with the high-energy laser light is printed in the color derived from the laser color former (B2). It is printed in color (3b in FIG. 1) ([II] in FIG. 1). In the manner described above, a molded article 2 with multicolor printing printed in two or more different color tones can be obtained.

In addition, by irradiating the laser-printing molding 1 with a low-energy laser beam, a wide-area printed portion (3a in FIG. 2) of a color derived from the laser coloring agent (B1) is formed, and then, By irradiating the printed area with a high-energy laser beam, the irradiated area is printed in a mixed color of the color derived from the laser coloring agent (B2) and the color derived from the laser coloring agent (B1). A section (3b in FIG. 2) can be formed. In the manner described above, it is possible to obtain a molded article 2a with multicolor printing printed in two or more different color tones.

The molded product with print thus produced may be provided with a protective layer on the surface having the printed portion. The material constituting this protective layer may be selected depending on the purpose and application, and is not particularly limited.

The molded article with print is useful for, for example, electrical/electronic applications, automobile applications, general miscellaneous goods applications, building members, and the like, and is particularly useful for automobile parts, such as engine room module parts, intake manifolds, underhood parts, radiator parts, and the like. It can be used for cockpit module parts used for instrument panels and the like. Other uses include, for example, electronic components for personal computers, liquid crystal projectors, mobile devices, and mobile phones.

4. Examples Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to these Examples. "Parts" and "%" in the examples are based on mass unless otherwise specified.

4.1. Example 1
4.1.1. Preparation of Molded Body for Laser Marking Each component of the types and parts by mass shown in Table 1 was kneaded for 5 minutes at a screw rotation speed of 100 rpm and a cylinder temperature of 200° C. using Labo Plastomill (manufactured by Toyo Seiki Co., Ltd., model number: 4C150). A laser marking composition was prepared. Then, after preheating the obtained composition for laser printing at 200° C. for 5 minutes in a compression press, it was pressure-molded at 30 kgf/cm ² to form a circular plate with a diameter of 90 mm and a thickness of 1 mm for laser printing. A compact was obtained.

4.1.2. Printing process The surface of the laser-printing molding obtained above is irradiated with a laser with a wavelength of 355 nm at a scanning speed of 600 mm / s and an output of 1.3 W (laser irradiation condition B) to record company information of Japan Coloring. A two-dimensional bar code of 14 mm×14 mm was printed, and after confirming the color development of the printed portion, the sharpness of the print was evaluated as described below.

4.1.3. Evaluation method <Clearness of printed part>
The sharpness of printing was evaluated by visual observation of the printed portion according to the following evaluation criteria. Table 1 shows the results.
(Evaluation criteria)
・When the contour of the print was clear, it was judged to be good and marked with “○”.
・If the outline of the print is unclear, it is judged to be defective and marked with "x".

<Color development of the fabric color>
The molded article for laser printing was visually observed, and the coloring of the base color was observed and evaluated according to the following evaluation criteria. Table 1 shows the results.
(Evaluation criteria)
・Compared with the color tone of the polymer (A), when no change in the color tone of the molded product for laser printing was observed, it was judged to be good because there was no deterioration due to the molding process, and was marked with "○".
・If the color tone of the molded body for laser printing was changed in comparison with the color tone of the polymer (A), it was judged to be defective because the quality had deteriorated due to the molding process, and was indicated as "x".

<Bleed-out property>
The printed portion was wiped off with BEMCOT, and whether or not the printed portion was transferred was evaluated according to the following evaluation criteria. Table 1 shows the results.
(Evaluation criteria)
- When transfer to Bemcot was not observed, it was judged to be good and marked with "○".
・When transfer to Bemcot was observed, it was judged to be defective and marked with "x".

4.2. Examples 2-17, Comparative Examples 1-4
A molded body for laser printing was prepared in the same manner as in Example 1, except that the laser irradiation conditions were changed as appropriate and the composition of the composition was changed to the composition shown in Table 1 or Table 2. Color development and bleed-out properties were evaluated. The results are shown in Table 1 or Table 2.

4.3. Examples 18 and 19
10 g of the laser coloring agent shown in Table 2 was added to 50 mL of a 0.07% by mass ethanol solution of sodium hydroxide and stirred for 15 minutes. Thereafter, the precipitate was filtered, washed and dried so that the content of compound (C) shown in Table 2 was obtained. The compound (C) prepared in this manner is mixed with each component so that the types and content ratios shown in Table 2 are obtained, and a screw is used with a Laboplastomill (manufactured by Toyo Seiki, model number: 4C150). The mixture was kneaded for 5 minutes at a rotation speed of 100 rpm and a cylinder temperature of 200° C. to prepare a composition for laser printing. Then, after preheating the obtained composition for laser printing at 200° C. for 5 minutes in a compression press, it was pressure-molded at 30 kgf/cm ² to form a circular plate with a diameter of 90 mm and a thickness of 1 mm for laser printing. A compact was obtained. Thereafter, in the same manner as in Example 1, the sharpness of printing, the color development of the base color, and the bleed-out property were evaluated. Table 2 shows the results.

4.4. Example 20
Instead of the 0.07% by mass sodium hydroxide ethanol solution, 50 mL of 0.1% by mass ammonium acetate ethanol solution was used, and the composition was changed to the composition shown in Table 2. A molded article for laser printing was prepared in the same manner as in Example 18, and the sharpness of printing, the development of the background color, and the bleed-out property were evaluated. Table 2 shows the results.

4.5. Example 21
Same as Example 18, except that two types of laser irradiation conditions (laser irradiation condition A and laser irradiation condition B) with different irradiation conditions were used in the printing process, and the composition of the composition was changed to the composition shown in Table 2. A molded product for laser printing was prepared as above, and the sharpness of printing, the color development of the base color, and the bleed-out property were evaluated. Table 2 shows the results.

4.6. Evaluation Results Tables 1 and 2 below show the composition and evaluation results of the laser-printing composition for producing the laser-printing moldings in each of Examples and Comparative Examples.

The abbreviations of the laser irradiation conditions in Tables 1 and 2 below are as follows.・A: Laser wavelength 1064 nm, output 25 W / scanning speed 25 mm / s
・B: Laser wavelength 355 nm, output 2 W / scanning speed 600 mm / s

The name or abbreviation of each component in Table 1 or Table 2 above is as follows.
<Polymer (A)>
・PMMA: Mitsubishi Chemical Co., Ltd., product name “Acrypet”, polymethyl methacrylate resin ・PS: PS Japan Co., Ltd., product name “HF77”, polystyrene ・POM: Mitsubishi Engineering Plastics Co., Ltd., product name “F20-03” ”, Polyacetal resin / PE: manufactured by Japan Polyethylene Co., Ltd., trade name “Novatec”, polyethylene resin <laser coloring agent (B1)>
・R-40: trade name, manufactured by Yamamoto Kasei Co., Ltd., 3,3-bis (1-n-butyl-2-methyl-3-indolyl) phthalide ・BLUE63: trade name, manufactured by Yamamoto Kasei Co., Ltd., 3-(4- Diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methyl-3-indolyl)-4-azaphthalide LCV-L: trade name, manufactured by Yamada Chemical Industry Co., Ltd., 3,3-bis(p-dimethyl) Aminophenyl)-6-dimethylaminophthalide <laser coloring agent (B2)>
・ LMG: Tokyo Chemical Industry Co., Ltd., trade name “Leuco Malachite Green”, 4,4′-tetramethyldiaminotriphenylmethane ・ LCV: Fuji Film Wako Pure Chemical Co., Ltd., trade name “Leuco Crystal Violet”, Tris (4 -dimethylaminophenyl)methane <filler>
・ ITO: Mitsubishi Materials Corporation, trade name “E-ITO”, indium tin oxide, primary particle size 0.03 μm
<Developer>
・ PBT: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name “Pentabromotoluene”
・ HBB: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd., trade name “Hexabromobenzene”

As is clear from the above Tables 1 and 2, according to the laser-printing moldings prepared from the laser-printing compositions of Examples 1 to 21, even after the kneading and molding steps, the moldings were colored. was suppressed, and it was found that chromatic colors could be developed by irradiating the surface of the molded article with a laser beam. In addition, according to the laser-printing moldings prepared from the laser-printing compositions of Examples 1 to 21, bleeding out of the laser color former in the printed portion can be effectively suppressed, and color transfer to other materials can be prevented. It has also been found that it can be suppressed.

On the other hand, in the molded articles prepared from the compositions of Comparative Examples 1 to 4, the base color of the molded article obtained through the kneading and molding process of the composition was observed, or the laser coloring agent in the printed part was not colored. Bleed out was observed.

The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same function, method, and result, or configurations that have the same purpose and effect). Moreover, the present invention includes configurations in which non-essential portions of the configurations described in the embodiments are replaced. Moreover, the present invention includes a configuration that achieves the same effects as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the present invention includes configurations obtained by adding known techniques to the configurations described in the embodiments.

1... Molded body for laser printing, 2, 2a... Molded body with multicolor printing, 3a... Printed part 1, 3b... Printed part 2

Claims (7)

a polymer (A);
at least one laser coloring agent (B) selected from the group consisting of a laser coloring agent (B1) containing a compound having a lactone skeleton and a laser coloring agent (B2) containing a compound having a triarylmethane skeleton;
a compound (C) having a first acid dissociation constant (pKa) of 9 or more;
contains
The compound (C) is at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, potassium acetate, and potassium formate,
Containing 0.05 parts by mass or more and 25 parts by mass or less of the laser coloring agent (B) with respect to 100 parts by mass of the polymer (A) ,
A composition for laser printing, containing 0.0001 parts by mass or more and 1 part by mass or less of the compound (C) with respect to 100 parts by mass of the polymer (A) . When the content of the laser color former (B) is M _B (parts by mass) and the content of the compound (C) is M _C (parts by mass), M _C /M _B is 0.005 to 10. The composition for laser marking according to claim 1, wherein 3. The composition for laser printing according to claim 1 , wherein the compound having a lactone skeleton is a compound having a fluoran skeleton. 4. The method according to any one of claims 1 to 3 , further comprising at least one compound selected from the group consisting of lanthanum hexaboride, tungsten cesium oxide, indium tin oxide (ITO) and antimony tin oxide. A composition for laser marking as described. 5. The composition for laser marking according to any one of claims 1 to 4 , further comprising an organic halide. A molded article for laser marking, which is produced using the composition for laser marking according to any one of claims 1 to 5 . After mixing the laser coloring agent (B) and the compound (C) having a first acid dissociation constant (pKa) of 9 or more, mixing them with the polymer (A) ,
The laser color former (B) is at least one selected from the group consisting of a laser color former (B1) containing a compound having a lactone skeleton and a laser color former (B2) containing a compound having a triarylmethane skeleton. ,
A method for producing a composition for laser printing , wherein the compound (C) is at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, potassium acetate, and potassium formate .

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