JPH0648042A - Marking composition - Google Patents

Abstract

PURPOSE:To provide a marking composition which can develop a color in clear white by irradiation with a laser beam. CONSTITUTION:A marking composition containing at least one component selected from a thermoplastic resin, talc of 1-300wt.% of the resin, calcium carbonate, alumina, clay, magnesium oxide, and magnesium hydroxide, and a molded product or a film made of the composition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to marking compositions and moldings obtained therefrom. More specifically, the present invention relates to a marking composition for producing a clear white color on a surface of a molded thermoplastic resin by irradiating a laser beam with a sharp mark, and a resin molded product or a film obtained therefrom. It is a thing.

[0002]

2. Description of the Related Art In recent years, electronic parts such as ICs, resistors, capacitors and inductors, electrical parts such as relays, switches, connectors and printed circuit boards, housings for electric products, automobile parts, machine parts, cables, sheets and packaging. As a method for marking the manufacturer name, article name, manufacturing date, etc. on the surface of various containers such as sheets, cards, foods or pharmaceuticals, caps of containers, etc., non-contact and fast marking speed, Laser marking has become popular because of its ease of automation and process control.

Laser marking is a polymer organic material,
Marking is performed by directly irradiating the surface of parts made of metal, etc. with laser light and changing part of the surface by thermal decomposition or evaporation, or by changing the color of the irradiated part due to discoloration or decolorization. Is to do. However, in this marking method, when a thermoplastic resin is used as the base material to be marked, the resin may not be able to mark the laser beam by passing through it, or even if the resin absorbs the laser beam to cause etching. There is a problem that clear marking cannot be performed only by melting the resin, and that it is difficult to develop a clear color even when a coloring agent is used.

[0004]

Even when a thermoplastic resin is used as a base material for laser marking, a marking composition that develops a clear white color is desired.

[0005]

The inventors of the present invention have reached the present invention as a result of intensive studies to solve the above-mentioned problems. That is, the present invention includes (1) a thermoplastic resin, and 1 to 30 with respect to the thermoplastic resin.
Marking composition containing 0% by weight of one or more of talc, calcium carbonate, alumina, clay, magnesium oxide, aluminum hydroxide, silica, magnesium carbonate, magnesium hydroxide (2) Thermoplastic resin A laser marking composition of the above item (1) which is polypropylene or polyethylene (3) A resin molded product obtained from the composition of the above item (1) (4) A film obtained from the laser marking composition of the above item (1) provide. The present invention will be described in detail.

The particle size of talc, calcium carbonate, alumina, clay, magnesium oxide, aluminum hydroxide, silica, magnesium carbonate, or magnesium hydroxide (filler) used in the present invention is 0.1 to 100.
The range of μ is preferable, and 0.2 to 50 μ is particularly preferable. Also, the amount used is 1 to 30 with respect to the thermoplastic resin.
It is 0% by weight, and particularly preferably 2 to 250% by weight. If the content is 1% by weight or less, clear contrast cannot be obtained, and if it exceeds 300% by weight, the moldability is remarkably deteriorated and it cannot be used. Further, the fillers may be used as a mixture of two or more kinds at an arbitrary ratio. Examples of particularly preferred combinations include calcium carbonate / talc,
Alumina / talc, silica / talc, calcium carbonate / silica, calcium carbonate / alumina, aluminum hydroxide / talc, magnesium hydroxide / talc, calcium carbonate / aluminum hydroxide, calcium carbonate / magnesium hydroxide.

The thermoplastic resin used in the present invention may be any one as long as it exhibits plasticity by heat. Specific examples thereof include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polymethacrylate, polyacrylonitrile, polycarbonate and copolymers thereof, polyethylene terephthalate, polybutylene terephthalate,
Polyesters such as wholly aromatic polyesters, polyurethane elastomers, polyamides, fluororesins, polyacetals, polyether ether ketones, polyether sulfones, polysulfones, polyphenylene sulfides, polyphenylene ethers, polyphenylene oxides, but especially polypropylene, Polyethylene, polyethylene terephthalate, polycarbonate,
Polyphenylene sulfide, ABS resin and polyvinyl chloride are preferred.

Further, additives and the like can be added to the laser marking composition of the present invention if necessary. Examples of the additives include colorants, fillers, lubricants and plasticizers. Examples of coloring agents that can be used include carbon black, phthalocyanine, azo, disazo, quinacridone,
Anthraquinone, flavanthrone, perinone, perylene, dioxazine, condensed azo, various organic dyes of azomethine or methine type, titanium oxide, lead sulfate, zinc oxide, iron black, chrome yellow, zinc yellow, chrome vermilion, red iron oxide, cobalt purple, ultramarine blue Inorganic pigments such as navy blue, chrome green, chrome green, chrome oxide, and cobalt green are mentioned, and organic dyes are particularly preferable. If necessary, these organic and inorganic pigments are added in a proportion of 0.1 to 5.0% by weight with respect to the thermoplastic resin. Examples of fillers that can be used include mica, calcium silicate, glass fiber, carbon fiber and the like. These are usually added in the range of 0 to 100% by weight to the thermoplastic resin as needed.

Examples of lubricants that can be used include stearic acid, behenic acid and its esters or salts, waxes such as carnauba wax and polyethylene wax, and various surfactants. These are usually added in a proportion of 0.1 to 5.0% by weight with respect to the thermoplastic resin, if necessary. Examples of plasticizers that can be used include esters such as phthalic acid, phosphoric acid and sebacic acid. others,
If necessary, additives such as antioxidants, heat stabilizers, light stabilizers and flame retardants that are commonly used in the processing of plastics are used. These additives may be used in the form of a masterbatch when producing the marking composition of the present invention.

The marking composition of the present invention is a thermoplastic resin, usually one of talc having an average particle size of 100 μm or less, calcium carbonate, alumina, clay, magnesium oxide, aluminum hydroxide, silica, magnesium carbonate, magnesium hydroxide, or Two or more kinds and additives such as colorants, fillers, lubricants, plasticizers, heat stabilizers, etc. are added and uniformly blended using an extruder, a twin-screw kneader and a roll mill, and then pelletized or marbled form. It is obtained as a product at. The product thus obtained is molded into a resin molded product, a film or the like by a method known per se.

A molded article using the laser marking composition of the present invention is molded by a known method such as injection molding, extrusion molding, hollow molding, rotational molding, foam molding, powder molding, vacuum molding according to the molded article. It And its applications include automobiles such as containers for foods, detergents, pharmaceuticals, cosmetics, beverages and their caps, food trays, tubes, medical containers, clothing appliances, housings for home appliances, electric appliances, household appliances, bumpers, etc. Parts, car interior parts, audio products such as tape cassettes, information equipment products such as floppy disks, pipes, building materials, industrial parts, various containers, clothing containers, multi-layer containers, daily sundries, various office machines, office supplies For example, the same applications as various molded products containing a thermoplastic resin as a main component, which are generally commercially available, are mentioned.

A film using the laser marking composition of the present invention is an inflation process, a multilayer inflation process, or a T process used for forming a thermoplastic resin film.
It is produced by a known method such as die film processing, vertical-horizontal simultaneous biaxial centrifugation method by flat film method, vertical-horizontal sequential biaxial centrifugation method, tubular film method. The film produced in this way is a usual thermoplastic resin film such as food packaging, fiber packaging, miscellaneous goods packaging, packaging of chemicals, tapes, insulating materials, agricultural films, various sheets, various stickers, labels, etc. Used in the same field as. Further, the film of the present invention can be laminated by being brought into close contact with various base materials, that is, papers such as kraft paper and high-quality paper, plastic films, metal foils such as aluminum, and obtained as such. Examples of the use of the laminate include applications such as food containers for milk and alcohol, packaging materials for pharmaceuticals, packaging materials for foods, various sheets, various stickers, labels and the like.

By irradiating the surface of the thus obtained molded product with a carbon dioxide gas laser beam, a YAG laser beam, or an excimer laser beam, a white marking having a clear contrast can be obtained. As the irradiation amount of the laser light, for example, in the case of the TEA carbon dioxide gas laser, the irradiation amount of 3 to 6 J / cm ² is adopted.

[0014]

EXAMPLES The present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In Examples and Reference Examples, "part" means part by weight.

Example 1 Polyethylene (made by Chisso, UP Polyethylene J110K)
1000 parts, aluminum hydroxide (made by Nippon Light Metal, B
-703, 50 parts of average particle size 30 μ) and 3 parts of pigmented quinacridone red (Pigment Violet 19) were kneaded at 160 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This product was molded into a plate at 150 ° C. using an injection molding machine (Yamashiro Seiki SAV-40, hereinafter referred to as an injection molding machine), and a carbon dioxide gas laser (manufactured by Coherent Co., Marking was performed using Zymark 7000) to obtain a clear white mark.

Example 2 1000 parts of polyethylene (made by Chisso, mentioned above), aluminum hydroxide (made by Nippon Light Metal Co., Ltd., B-703, average particle size 3)
0 μ) 100 parts and 2 parts of pigmented phthalocyanine blue (Pigment Blue 16) at 160 ° C. using a biaxial kneader.
Was kneaded and pelletized with a pelletizer to obtain the marking composition of the present invention. This one using an injection molding machine 1
It was molded into a plate shape at 50 ° C., and the surface thereof was marked with the carbon dioxide gas laser to obtain a clear white mark.

Example 3 1000 parts of polyethylene (made by Chisso, mentioned above), aluminum hydroxide (made by Nippon Light Metal Co., Ltd., B-703, average particle size 3)
100 parts of 0 μ) was kneaded at 160 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This product is 150 ° C using an injection molding machine.
Was molded into a plate shape with, and the surface was marked with the carbon dioxide gas laser to obtain a clear white mark.

Example 4 Polypropylene (manufactured by Tonen, Tonen Polypro J-215) 1
000 parts, aluminum hydroxide (made by Nippon Light Metal Co., Ltd.,
50 parts, pigmented phthalocyanine blue (Pigment
Blue 16) Mix 2 parts at 200 ° C using a biaxial kneader.
Kneading, pelletizing with a pelletizer, the markin of the present invention
A gouging composition was obtained. This is 220 using an injection molding machine.
Molded into a plate at ℃, TEA carbon dioxide laser on the surface
(Blazar 6000 manufactured by Laser Technics)
26700V (4J / cm ²), Reduction ratio 1:
Marking under conditions of 2 gives a clear white mark
It was

Example 5 1000 parts of polyethylene terephthalate (Asahi Kasei, Sun pellet 3200G), 30 parts of aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., above), and 2 parts of pigmented phthalocyanine blue (Pigment blue 16) were added using a biaxial kneader. The marking composition of the present invention was obtained by kneading at 230 ° C and pelletizing with a pelletizer. This product was molded into a plate at 230 ° C. using an injection molding machine, and its surface was marked with a carbon dioxide laser (Zymark 7000 manufactured by Coherent Co., Ltd.) to obtain a clear white mark.

Example 6 Polypropylene (made by Chisso, Chisso Polypro K814
0T) 1000 parts, calcium carbonate (Maruo calcium super 1700, average particle size 2μ) 300 parts, pigmented phthalocyanine (CI Pigment Blue 16) 2
The parts were kneaded at 200 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This product was molded into a plate at 230 ° C. using an injection molding machine, and a carbon dioxide gas laser (BLAZAR 6000, manufactured by Laser Technics, hereinafter referred to as a carbon dioxide gas laser unless otherwise specified) on its surface. Was used under the conditions of 26700 V (4 J / cm ² ) and a reduction ratio of 1: 3 to obtain a clear white mark.

Example 7 Polypropylene (manufactured by Asahi Kasei, Asahi Kasei Polypro M150
0) 1000 parts, talc (Nippon Talc P-3, average particle size 3 μ) 400 parts, red pigment (Nippon Kayaku KST R
ED E-3B) 3 parts at 200 ° C. using a biaxial kneader
Was kneaded and pelletized with a pelletizer to obtain the marking composition of the present invention. Using an injection molding machine 2
Molded into a plate shape at 30 ° C., and using a carbon dioxide gas laser on its surface, 26700 V (4 J / cm ² ), reduction ratio 1: 3
A clear white mark was obtained by marking under the conditions.

Example 8 1000 parts of polypropylene used in Example 7, 100 parts of calcium carbonate (Super 1700 made by Maruo calcium, average particle size 2 μ), 100 parts of talc (P-3 made by Nippon Talc, average particle size 3 μ), 3 parts of pigmented phthalocyanine green (CI Pigment Green 7) was kneaded at 200 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This product was molded into a plate shape at 230 ° C. using an injection molding machine, and the surface thereof was subjected to a carbon dioxide laser at 26700 V (4 J / c).
m ² ), and a reduction ratio of 1: 3, marking was performed to obtain a clear white mark.

Example 9 Polyethylene (Asahi Kasei, Suntec M6545) 1
000 parts, 300 parts of alumina (Nippon Light Metal's A-33F, average particle size 0.7 μ), and 2 parts of pigmented quinacridone red (CI Pigment Violet 19) were kneaded at 200 ° C. using a biaxial kneader, The marking composition of the present invention was obtained by pelletizing with a pelletizer. This product was molded into a plate at 170 ° C. using an injection molding machine, and the surface thereof was subjected to a carbon dioxide gas laser at 26700 V (4 J / c).
m ² ), and a reduction ratio of 1: 3, marking was performed to obtain a clear white mark.

Example 10 1000 parts of polyethylene used in Example 9, 300 parts of silica (RD-8 made by Tatsumori, average particle size 15 μ), and 2 parts of pigmented phthalocyanine blue (CI Pigment Blue 16) are biaxial. The mixture was kneaded at 200 ° C. using a kneader and pelletized with a pelletizer to obtain a marking composition of the present invention.
This product was molded into a plate shape at 180 ° C using an injection molding machine, and the surface thereof was 26700 V using a carbon dioxide laser.
(4 J / cm ² ) and a reduction ratio of 1: 3 were applied to give a clear white mark.

Example 11 Polyethylene terephthalate (manufactured by Asahi Kasei, Sunpet 3)
200G) 1000 parts, clay 1500 parts, pigmented phthalocyanine blue (CI Pigment Blue 16) 5
The parts were kneaded at 200 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This product was molded into a plate at 250 ° C. using an injection molding machine, and the surface thereof was subjected to 26700 using a carbon dioxide laser.
Marking was performed under the conditions of V (4 J / cm ² ) and a reduction ratio of 1: 3 to obtain a clear white mark.

Example 12 Polyethylene terephthalate 100 used in Example 11
0 parts, 1000 parts magnesium oxide (manufactured by Ube Chemical),
Red pigment (KST RED E-3B made by Nippon Kayaku) 5
The parts were kneaded at 200 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This product was molded into a plate at 250 ° C. using an injection molding machine, and the surface thereof was subjected to 26700 using a carbon dioxide laser.
Marking was performed under the conditions of V (4 J / cm ² ) and a reduction ratio of 1: 3 to obtain a clear white mark.

Example 13 1000 parts of polypropylene used in Example 7, 800 parts of magnesium carbonate (manufactured by Tokuyama Soda) and 5 parts of pigmented phthalocyanine green (CI Pigment Green 7) were used at 200 ° C. using a biaxial kneader. Was kneaded and pelletized with a pelletizer to obtain the marking composition of the present invention. This was molded into a plate at 250 ° C using an injection molding machine,
A carbon dioxide laser was used on the surface of the 26700V (4
J / cm ² ) and a reduction ratio of 1: 3 were applied to give clear white marks.

Example 14 Polycarbonate (Taflon SC-25 manufactured by Idemitsu Petrochemical Co., Ltd.
0) 1000 parts, magnesium hydroxide 400 parts, and pigmented phthalocyanine blue (CI Pigment Blue 16) 3 parts were kneaded at 200 ° C. using a biaxial kneader,
The marking composition of the present invention was obtained by pelletizing with a pelletizer. This product was molded into a plate shape at 250 ° C. using an injection molding machine, and the surface of the product was molded with a carbon dioxide laser 26
Marking was performed under the conditions of 700 V (4 J / cm ² ) and a reduction ratio of 1: 3 to obtain a clear white mark.

Example 15 1000 parts of polypropylene used in Example 7, calcium carbonate (Maruo calcium super 1700,
Average particle size 2μ) 150 parts, talc (P- manufactured by Nippon Talc)
3, 50 parts of average particle size 3 μ), 50 parts of aluminum hydroxide (B-703 made by Nippon Light Metal Co., Ltd., average particle size 3 μ), 3 parts of red pigment (KST RED E-3B made by Nippon Kayaku) 2 parts
It was kneaded at 200 ° C. using a shaft kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This product was molded into a plate at 230 ° C. using an injection molding machine, and the surface thereof was irradiated with a carbon dioxide gas laser at 26700 V (4J
/ Cm ² ), and a reduction ratio of 1: 3, marking was performed to obtain a clear white mark.

Example 16 1000 parts of polypropylene used in Example 7, 200 parts of talc, alumina (A-33F made by Nippon Light Metal Co., average particle size 0.7 μ), pigmented phthalocyanine blue (C.
I. Pigment Blue 16) 3 parts was kneaded at 200 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This product was molded into a plate at 230 ° C using an injection molding machine, and the surface was marked with a carbon dioxide laser at 26700 V (4 J / cm ² ) at a reduction ratio of 1: 3 to give a clear white color. Got the mark.

Example 17 1000 parts of polypropylene used in Example 7, 200 parts of talc (P-3 manufactured by Nippon Talc, average particle size 3 μ), 200 parts of silica (RD-8 manufactured by Tatsumori, average particle size 15 μ) Kneading 3 parts of pigmented phthalocyanine blue (CI Pigment Blue 16) at 200 ° C. using a biaxial kneader,
The marking composition of the present invention was obtained by pelletizing with a pelletizer. This product was molded into a plate shape at 250 ° C. using an injection molding machine, and the surface of the product was molded with a carbon dioxide laser 26
Marking was performed under the conditions of 700 V (4 J / cm ² ) and a reduction ratio of 1: 3 to obtain a clear white mark.

Example 18 Polypropylene (made by Chisso, Chisso Polypro K814
0T) 1000 parts, calcium carbonate (Maruo calcium super 1700, average particle size 2μ) 300 parts, pigmented phthalocyanine (CI Pigment Blue 16) 2
The parts were kneaded at 200 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This product was molded into a plate shape at 230 ° C. using an injection molding machine, and the surface thereof was subjected to 26700 using a carbon dioxide laser.
Marking was performed under the conditions of V (4 J / cm ² ) and a reduction ratio of 1: 3 to obtain a clear white mark.

Example 19 1000 parts of polypropylene used in Example 18 and 250 parts of aluminum hydroxide (B-703 made by Nippon Light Metal Co., Ltd., average particle size 0.4 μ) were kneaded at 200 ° C. using a biaxial kneader, and pelletized. To obtain a marking composition of the present invention. This product was molded into a plate shape with an injection molding machine, and the surface was 26700 V using a carbon dioxide laser.
(4 J / cm ² ) and a reduction ratio of 1: 2 were applied to give a clear white mark.

Example 20 1000 parts of polypropylene used in Example 7 and 1000 parts of aluminum hydroxide (B-703 manufactured by Nippon Light Metal Co., Ltd., average particle size 0.4 μ) were used at 200 ° C. using a biaxial kneader.
Was kneaded and pelletized with a pelletizer to obtain the marking composition of the present invention. This product was molded into a plate shape with an injection molding machine, and the surface thereof was 26700 using a carbon dioxide laser.
Marking was performed under the conditions of V (4 J / cm ² ) and a reduction ratio of 1: 2 to obtain a clear white mark.

Example 21 Polyethylene (Asahi Kasei, Suntec M6545) 1
000 parts, aluminum hydroxide (made by Nippon Light Metal B-
303, average particle size 30μ) 2500 parts, pigmented quinacridone red (CI Pigment Violet 19) 5
The parts were kneaded at 200 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This product was molded into a plate shape with an injection molding machine, and the surface of the product was 26700 V (4 J / c) using a carbon dioxide laser.
m ² ), the reduction ratio was 1: 2, and marking was performed to obtain a clear white mark.

Example 22 Polystyrene (manufactured by Idemitsu Petrochemical, Idemitsu Styrol GP
HF10) 1000 parts, aluminum hydroxide (Nippon Light Metals B-153, average particle size 15 μ) 1000 parts, and pigmented phthalocyanine blue (CI Pigment Blue 16) 3 parts were kneaded at 200 ° C. using a biaxial kneader. Then
The marking composition of the present invention was obtained by pelletizing with a pelletizer. This product was molded into a plate shape by an injection molding machine, and the surface thereof was subjected to 26700 V (4 J /
cm ² ), and a reduction ratio of 1: 2 were applied to give clear white marks.

Example 23 Polyethylene terephthalate (manufactured by Asahi Kasei, Sunpet 3)
200G) 1000 parts, aluminum hydroxide (B-103 made by Japan Light Metals, average particle size 8μ) 400 parts, isoindolinone yellow (Irgazin Yellow 3RL made by Ciba Geigy) 5 parts at 200 ° C. using a biaxial kneader. The mixture was kneaded and pelletized with a pelletizer to obtain the marking composition of the present invention. This product was molded into a plate shape with an injection molding machine, and the surface was 26700 V using a carbon dioxide laser.
(4 J / cm ² ) and a reduction ratio of 1: 2 were applied to give a clear white mark.

Example 24 Polybutylene terephthalate (Teijin PBT manufactured by Teijin Ltd.)
C7000) 1000 parts, aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd. B-303, average particle size 30 μ) 400 parts,
3 parts of pigmented phthalocyanine green (CI Pigment Green 7) was kneaded at 200 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This is molded into a plate shape with an injection molding machine,
A carbon dioxide laser was used on the surface of the 26700V (4
J / cm ² ) and a reduction ratio of 1: 2 were applied to give markings, and clear white marks were obtained.

Example 25 ABS resin (Psycholac EX10 manufactured by Ube Saikon Corporation)
2) 1000 parts and 100 parts of aluminum hydroxide (B-153 manufactured by Nippon Light Metal Co., Ltd., average particle size: 15 μ) were kneaded at 200 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. . This product was molded into a plate shape with an injection molding machine, and the surface thereof was irradiated with a carbon dioxide gas laser at 26700 V (4 J / cm ² ) at a reduction ratio of 1:
Marking was performed under the condition of 2 to obtain a clear white mark.

Example 26 Polyvinyl chloride (Kanefuchi Chemical Co., Kane vinyl compound KVC I-229C) 1000 parts, aluminum hydroxide (Nippon Light Metal BW-53, average particle size 50)
μ) 500 parts, carbon black (Mitsubishi Kasei MA-
2 parts of 100) were kneaded using a twin-screw kneader at 140 ° C. and pelletized with a pelletizer to obtain a marking composition of the present invention. This is molded into a plate shape with an injection molding machine,
A carbon dioxide laser was used on the surface of the 26700V (4
J / cm ² ) and a reduction ratio of 1: 2 were applied to give markings, and clear white marks were obtained.

Example 27 Polyethylene (manufactured by Chisso, UP Polyethylene J110K)
1000 parts, aluminum hydroxide (made by Nippon Light Metal, B
-703, average particle size 30 μ) 100 parts and pigmented phthalocyanine blue (Pigment Blue 16) 2 parts were kneaded at 160 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a marking composition of the present invention. This product was molded at 150 ° C using an injection molding machine and has a diameter of 22 mm, h
A 5 mm cap was molded. The surface was marked with a carbon dioxide laser (Zymark 7000, manufactured by Coherent Co., Ltd.) to obtain a clear white mark.

Example 28 1000 parts of polyethylene used in Example 27, aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., B-703, average particle size 3)
0 μ) 100 parts, and 2 parts of pigmented phthalocyanine blue (Pigment Blue 16) 160 using a biaxial kneader.
The marking composition of the present invention was obtained as a film having a thickness of 500 μ by kneading at a temperature of ℃. Carbon dioxide laser (Zymark 7000 manufactured by Coherent) on the surface
Marking was performed using to obtain a clear white mark.

Comparative Example 1 Polyethylene (made by Chisso, UP Polyethylene J110K)
1000 parts was molded into a plate shape at 150 ° C. using an injection molding machine, and a carbon dioxide gas laser (manufactured by Coherent,
Marking was performed using Zymark 7000), but no mark was obtained.

Comparative Example 2 A mixture of 1000 parts of polyethylene used in Comparative Example 1 and 2 parts of pigmented phthalocyanine blue (Pigment Blue 16) was molded into a plate shape at 150 ° C. using an injection molding machine, and carbon dioxide was formed on the surface of the mixture. Gas laser (made by Coherent,
Marking was performed using Zymark 7000), but no mark was obtained.

Comparative Example 3 Polypropylene (manufactured by Chisso, Chisso Polypro K814
0T) 1000 parts, pigmented phthalocyanine blue (C.
I. Pigment Blue 16) (2 parts) was kneaded at 200 ° C. using a biaxial kneader and pelletized with a pelletizer to obtain a comparative marking composition of the present invention. This product was molded into a plate shape at 230 ° C. using an injection molding machine, and the surface thereof was subjected to a carbon dioxide laser at 26700 V (4 J / c).
m ² ), and the reduction ratio was 1: 3, but the marking was not obtained at all.

Comparative Example 4 Polyethylene (Asahi Kasei, Suntec M6545) 1
2,000 parts and 2 parts of pigmented quinacridone red (CI Pigment Violet 19) 2 using a biaxial kneader
The mixture was kneaded at 00 ° C. and pelletized with a pelletizer to obtain a comparative marking composition of the present invention. This product was molded into a plate shape at 170 ° C. using an injection molding machine, and the surface was marked with a carbon dioxide laser at 26700 V (4 J / cm ² ) at a reduction ratio of 1: 3. I couldn't get it at all.

[0047]

EFFECTS OF THE INVENTION A marking composition capable of producing a clear white color upon irradiation with laser light was obtained.

Claims (4)

[Claims] 1. A thermoplastic resin, 1 for said thermoplastic resin.
To 300% by weight of talc, calcium carbonate, alumina, clay, magnesium oxide, aluminum hydroxide, silica, magnesium carbonate, magnesium hydroxide, or a marking composition containing two or more thereof. 2. The marking composition according to claim 1, wherein the thermoplastic resin is polypropylene or polyethylene. 3. A resin molded product obtained from the composition of claim 1. 4. A film obtained from the marking composition of claim 1.