JPH09286169A - Laser marking recording body and laser marking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording body and recording method having a high coloring sensitivity and qualified image stability for producing indication bodies or documents by the agency of marking of a laser beam. SOLUTION: A sensitizing layer including a laser sensitizing agent for converting a laser beam in heat is formed between a support body and a coloring layer, and by effectively destroying and corroding the coloring layer even by a weak laser beam, much information recording can be implemented at a high speed. For the laser sensitizing agent, there is used one kind selected from the group consisting of an inorganic silicic acid metallic salt and an inorganic boric acid metallic salt such as synthetic mica, cordierite, kaolin. Then, it is formed that a content of the sensitizing agent in the sensitizing layer is made 5-90wet.%, and the film thickness of the coloring layer is made 0.1-10μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various kinds of display bodies which require a label such as a label attached to the surface of packaging of factory-shipped products or factory-shipped products. Entered product name, lot number, production time, expiration date,
The present invention relates to a laser marking display body and a laser marking method capable of efficiently and simply marking an arbitrary pattern such as a bar code immediately before production, packaging, in a line, and immediately after.

[0002]

2. Description of the Related Art Generally, a laser marking method for destroying a surface layer is to irradiate or scan a surface of a base material with a laser beam having an arbitrary pattern to destroy the surface layer of the base material by evaporation / scattering to form an exposed substrate. This is a marking method for obtaining visibility by utilizing the contrast obtained by the difference in lightness or hue from the non-destructive portion or the irregular reflection of light due to the unevenness of the destroyed portion. Compared with diffuse reflection of light due to fine irregularities on the surface, for example, the colored ink layer printed on the wrapping paper or paper label is destroyed by laser light, and the white of the exposed underlying paper and the coloring of the non-destructive part The method using the brightness and hue difference from the ink had high visibility, was simple and effective.

However, this method requires high laser energy to vaporize or scatter the colored layer. Therefore, in the case of a high-speed pulsed laser that uses a mask, it is necessary to narrow down the rectangular or circular irradiation light with an optical system to increase the laser energy density, and the area that can be marked becomes narrower. The amount of information that can be produced is limited, or laser irradiation must be performed twice and marking must be performed. Further, in the case of a continuous-wave scanning laser that scans a laser beam of a small area, in order to perform destruction with high energy, it is necessary to irradiate the portion to be destroyed with laser light for a long time, which requires a scanning time. It took time to make the necessary markings.

In recent years, particularly in the field of packaging and various labels, the amount of information that must be displayed online such as expiration date display, lot number, etc. has increased due to compliance with the PL method.
There has been a demand for an efficient marking method that is reliable, high speed in the production process.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, the present invention is a laser marking method which has a feature of online, non-contact and high speed marking, which enables efficient marking of a large amount of information at one time. It is an object of the present invention to provide a laser marking recording material, particularly a laser marking display material, in which a colored layer can be destroyed by laser irradiation energy.

[0006]

Therefore, as a result of diligent studies, the present inventors have found that a recording material having a colored layer on a support contains a laser sensitizer between the support and the colored layer. It has been found that when a recording material having a sensitized layer is used, the laser irradiation energy required to destroy the colored layer can be significantly reduced, and high-speed laser marking of a large area can be performed at one time. The present invention has been reached.

That is, according to the present invention, in a recording material having a colored layer on a support, a sensitizing layer containing a laser sensitizer is formed between the support and the colored layer, and the colored layer is a laser. The present invention relates to a recording medium for laser marking, which is formed into a thin layer or toned so as not to prevent the light from reaching the sensitizing layer, and is destroyed or etched by heat.

Further, the present invention is a laser marking in which a recording material having a colored layer on a support is irradiated with laser light for marking characters and / or graphics, and the colored layer is destroyed by heat and etched to perform marking. In the method,
A sensitizing layer containing a laser sensitizer is formed between the support and the coloring layer, and the coloring layer is thinned or toned so as not to prevent the laser light from reaching the sensitizing layer. To a laser marking method.

In such a recording medium or laser marking method, as the laser sensitizer, one or more of inorganic boric acid metal salts and inorganic silicic acid metal salts are used.
As the inorganic metal silicate, any one or more of synthetic mica, cordierite and kaolin is particularly preferably used.

The amount of the laser sensitizer blended in the sensitizing layer may be 5 to 90% by weight.

In the present invention, the thickness of the colored layer is
The thickness is preferably in the range of 0.1 to 10 μm, and within this range, it is effectively destroyed and etched by heat. Moreover, in the present invention, in the case where the sensitizing layer and / or the support has a color contrast with the colored layer, when the colored layer is destroyed by heat and is etched, it is positioned below the colored layer. As a result, the color of the sensitizing layer becomes visible and clear marking is obtained.

Further, it is desirable that an overcoat layer for protecting the coloring layer is formed on the coloring layer of such a recording material. This overcoat layer can be effectively marked by destroying it together with the colored layer by the laser beam during marking.

The recording material of the present invention is particularly effective when used as a display label.

Since the present invention is as described above, when laser recording is carried out by irradiating a recording material having a colored layer on a support with a laser beam, a sensitization for laser is carried out between the support and the colored layer. Since the sensitizing layer containing the agent is formed, the colored layer is surely destroyed to achieve the marking.

There are various effective substances as the laser sensitizer, the details of which will be described later, but when irradiated with laser light, they reach the layer containing the laser sensitizer through the colored layer, Since the laser sensitizer efficiently converts the irradiated laser light into heat, higher heat can be obtained with laser energy having a lower energy density than in the case without the laser sensitizer, and it is at the top. It is presumed that the colored layer is destroyed by evaporation and scattering due to its heat, and the purpose can be achieved more effectively by appropriately selecting the kind of the adhesive used for the colored layer, the sensitizing layer and the like.

Although it is convenient to form the sensitizing layer separately on the existing support from various viewpoints, it is also possible to form the sensitizing layer by incorporating a sensitizer in the support itself. The effects of the invention can be achieved, and such embodiments are also included in the scope of the present invention. Also, the support is
The form is not limited, and may be sheet-like or three-dimensional.

[0017]

As the laser sensitizer used in the present invention, any known substance can be used as long as it is a substance capable of converting laser light into heat. The laser sensitizer is itself dispersed in the support or a layer on the support in the form of particles or is dissolved in a resin. When present in the form of particles, the particle diameter is usually 50 μm or less, and preferably 0.1 to 10 μm. Further, these laser sensitizers are previously surface-treated with a titanium coupling agent, a silane coupling agent, a metal soap, a surfactant, a resin or the like in order to improve the uniformity when dispersed in a particulate form. Good.

Here, as the laser sensitizer used for a laser having a wavelength in the far infrared region, inorganic boric acid metal salts, inorganic silicic acid metal salts and the like are preferable. As the inorganic boric acid metal salts, zinc borate, calcium borate, which is a metal salt of boric acid,
Magnesium borate, lithium borate, aluminum borate,
Examples thereof include sodium borate, manganese borate, barium borate and the like, which may contain bound water or may be anhydrous.

As the inorganic metal silicates, there are sodium silicate, co-gellite and natural mica (mascobite, which is a metal salt of silicic acid or a composite metal salt of aluminum silicate).
Phlogovite, biotite, sericite, etc.), synthetic mica (fluorinated phlogopite, fluorine tetrasilicon mica, etc.), talc, kaolin, bentonite, zeolite (A type and X type), etc., and these include bound water. It may be anhydrous.

Of these, synthetic mica, cordierite and kaolin are preferable from the viewpoint of efficient destruction of the colored layer.
As the laser sensitizer used for the laser in the visible to near-infrared wavelength region, a known near-infrared absorbing dye can be used,
Examples thereof include cyanine dyes, quinone dyes, phthalocyanine dyes, naphthalocyanine dyes, dithiolene metal complexes, phenylenediamine metal complexes, and indoaniline-based metal complexes.

These laser sensitizers may be used alone or in combination of two or more kinds. As the support of the present invention,
It is not particularly limited, and is selected from the durability and design required depending on the purpose of use as appropriate. Conventional plain paper, art paper, coated paper, aluminum vapor-deposited paper, vinyl chloride resin, polyester resin Sheets made of polyolefin resin, metal or the like, synthetic paper, or laminated paper can be used. It may be a three-dimensional object.

Even when the support contains a laser sensitizer, the same effect can be obtained if the content is sufficient. The method of incorporating the laser sensitizer in the support varies depending on the method of producing the support.For example, in the case of paper, it is in a liquid for performing ordinary papermaking, or in a liquid to be coated for art paper or coated paper. In addition, a laser sensitizer is dispersed or dissolved by an appropriate general method, papermaking or coating is performed, and paper containing laser sensitizer, coated paper, art paper or the like can be produced.

In the case of a plastic film, in the step of producing the film by T-die extrusion molding or the like, it is contained in the resin to be formed into a film or is formed into a film together with a resin containing a laser sensitizer in a high concentration in advance. Just do it. The thickness of the support is not particularly limited.

As a method for forming the sensitizing layer or the coloring layer on the support, no special method is required for forming the layer, and a conventional coating method can be used.
Examples of coating methods include gravure printing, offset printing, flexographic printing, screen printing, air knife coating, blade coating and the like.

The coating thickness of the sensitizing layer is 0.1 to 20 after drying.
g / m ² or 0.1 to ²⁰ μm, preferably 0.5 to
It is 10 g / m ² or 0.5 to 10 μm. The coating thickness of the coloring layer is easy to be destroyed by evaporation and scattering even if the energy density is low, and the smaller the scattering amount of the coloring layer is, the less the surrounding contamination is. The coating film thickness is good, and after drying, it is 0.1 to 10 g / m ² or 0.1 to 10 μm, preferably 0.5 to 5 g / m ² or 0.5 to 5 μm.

The material forming the layer is a fixing agent composed of a resin component suitable for these coating methods, and in the case of a layer containing a laser sensitizer, the laser sensitizer is present. In this case, colorants such as pigments and dyes are dispersed or dissolved in the form of particles. As the resin component, for example, polyamide resin, polybutyral resin, polyvinyl butyral resin, polyvinyl alcohol resin, nitrocellulose resin, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, urethane resin, petroleum resin, chloride Rubber resin, cyclized rubber resin, alkyd resin, phenolic resin,
There are epoxy resins and the like, and these resin components are used in a state of being dissolved or dispersed in an organic solvent, water or the like suitable for the coating method at the time of coating. Alternatively, it may be dried by a method such as heat and energy rays without using a solvent.

In the layer containing the laser sensitizer, for example, a filler such as calcium carbonate, silica, alumina, magnesia, titania, barium sulfate, zinc oxide or the like, and a colorant such as a pigment or dye may be added, if necessary. Can be added.

The colorant added to the layer containing the laser sensitizer is visually recognized by the contrast between the exposed portion of the layer containing the laser sensitizer and the exposed portion of the laser-sensitized layer and the undestructed portion after laser irradiation. From the viewpoint of properties, it is preferable to use a coloring agent having a hue different from that of the coloring layer.

The content of the laser sensitizer in the dry coating film of the layer containing the laser sensitizer is preferably as high as possible in the coatable range, and is 5 to 90 wt%, preferably 30 to 80 wt.
% Is good. The coloring agent and the filler used in the colored layer are not particularly limited in chemical composition, structure, color, etc., and are generally used dyes and pigments, fluorescent dyes, extender pigments, organic fine particles,
Hollow particles, metal powder, metal-coated particles and the like,
Among them, those having a high laser light transmittance are preferable (carbon black has a low transmittance), and the content of the colorant in the dry coating film is preferably as small as possible within the range in which the required hue and color density can be obtained. 0.1-80 wt% is preferable.

The sensitizing layer and the colorant layer may each have a multilayer structure of two or more layers, if desired. Further, as long as the required physical properties of the support are not deteriorated, the resin components of the fixing agent used in the layer containing the sensitizer for laser and the coloring layer are different, so that evaporation at low energy and destruction due to scattering are efficient. Become. Further, in order to facilitate destruction at a low energy density, a release agent such as a water-repellent or oil-repellent agent such as silicon may be added to the layer containing the laser sensitizer.

Further, in order to improve the smoothness of the support and the adhesion between the support and the layer containing the laser sensitizer (ie, the sensitizing layer), a layer between the laser sensitizer-containing layer and the support is provided. Undercoat containing resins and fillers containing various polymers as main components such as nitrocellulose resin, polyamide resin, acrylic resin, polyurethane resin, polyester resin, epoxy resin, silicone resin, and fluorine resin. You may form a layer.

In order to improve the durability of the laser marking recording material of the present invention or to prevent damage due to external force, polyethylene resin, polypropylene resin, ethylene-vinyl acetate resin, ethylene-ethyl acrylate resin, Acetate nitrocellulose resin, nitrocellulose resin, polyamide resin, acrylic resin,
Polyurethane-based resin, polyester-based resin, epoxy-based resin, silicon-based resin, fluorine-based resin, etc. as a main component and fillers, lubricants, UV absorbers, antioxidants, water repellents, oil repellents, etc. for these resins The overcoat layer containing the auxiliary agent can be used on the coloring layer.

The addition of an ultraviolet absorber or an antioxidant to the overcoat layer suppresses the deterioration of the display body due to light or heat,
Improves long-term storage of the display. It is preferable that the resin species used for the overcoat layer have a low thermal decomposition temperature of the resin so as not to hinder the destruction of the colored layer due to evaporation and scattering.
0 ° C or lower, preferably 350 ° C or lower. Further, the film thickness of the overcoat layer also affects the evaporation of the colored layer and the destruction due to the scattering, so that it is preferably 15 μm or less. Preferably, acrylic resin, nitrocellulose resin,
Polyamide resin is preferable.

The coating liquid for the support, the layer containing the sensitizer for laser and the coloring layer includes a dispersant, a viscosity modifier, a filler, a leveling agent, a lubricant, an ultraviolet absorber, an antioxidant and an antistatic agent. Auxiliaries classified as agents, colorants, heat-sensitizing sensitizers, preservatives and the like can be added.

In order to carry out the method of the present invention, the recording material for laser marking of the present invention may be marked by irradiating it with a laser beam, and a laser device having an output of 0.2 joule / cm ² · pulse or more Preferable is a pulsed laser which gives an energy of 0.3 joule / cm ² · pulse or more to the irradiation surface, or a scanning laser which has an output of 0.5 W or more, for example, a carbon dioxide laser,
Carbon monoxide laser, semiconductor laser, yttrium aluminum garnet (YAG) laser and the like,
Above all, Transversely Excited
Atomospheric Pressure (TE
Since the A) type carbon dioxide laser can irradiate a wide area at high speed with one pulse, a lot of information can be marked at high speed, which is particularly preferable.

[0036]

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

[Black ink A] Black ink for gravure printing using polyamide resin [Brightup DB manufactured by Dainippon Ink and Chemicals, Inc.
L 805 black ink] (diluting solvent: toluene / isopropyl alcohol / ethyl acetate)

[Ink Ink B Blend] N-Methoxymethyl Nylon 15 parts [Trezin F-30 manufactured by Teikoku Kagaku Sangyo Co., Ltd.] Carbon black 10 parts Methanol 75 parts Shake the above blend with glass beads for 3 hours in a paint conditioner. Then, black ink B was prepared. (Diluting solvent: Methanol)

[Ink Ink C] 100 parts of black ink for gravure printing using polyamide resin [Bright Top D-BL 805 black ink manufactured by Dainippon Ink and Chemicals, Inc.] 17 parts of fluorine tetrasilicon mica (diluting solvent: toluene / isopropyl) Alcohol / ethyl acetate)

[Blend of White Ink A] 100 parts of white ink for gravure printing using polyamide resin [BRIGHTUP D-BL 708 white manufactured by Dainippon Ink and Chemicals, Inc.] 17 parts of laser sensitizer (diluting solvent: toluene / (Isopropyl alcohol / ethyl acetate)

[OP Varnish] Nitrocellulose-based OP varnish for gravure printing [SF815 manufactured by Dainippon Ink and Chemicals, Inc.] (diluting solvent: ethyl acetate)

In the dispersion of the laser sensitizer and the adjustment of the black ink C, the predetermined composition was shaken with glass beads in a paint conditioner for 3 hours for adjustment. Each ink used is 18 ± 1 in # 3 Zahn cup viscosity measurement
Adjust the printing viscosity by adding a diluent solvent so that
A recording material was produced by performing gravure printing on a base paper in a predetermined order using a 70-line / cm heliogravure plate.

Laser marking on the produced recording medium is as follows.
Irradiation energy density on the irradiation surface = 0.31 to 0.54 joules / cm ² pulse through a metal mask cut out in a letter shape using a TEA carbon dioxide laser irradiation device). In each case, the black ink layer was evaporated / scattered by laser irradiation and laser marking with high visibility was obtained. The lower the energy density,
It is useful because it has high sensitivity and can mark a wide print area.

The irradiation energy density of the laser is determined by the detector {model number E manufactured by GENTEC Co.
D-500} is installed, 1 pulse of carbon dioxide laser light is irradiated to this, and the total output energy converted from the detector output voltage with a laser energy meter {GENTEC model number EM-1} is read, Divide this measured value by the area of the total laser beam on the irradiation surface to obtain a unit area of 1
The irradiation energy density per pulse was obtained.

Examples 1 to 5 White ink A in which the laser sensitizer shown in Table 1 was dispersed, black ink A, and OP varnish were gravure-printed in this order on aluminum vapor-deposited paper to obtain a recording medium, which was irradiated with laser. I got a white marking on a black background. The evaluation results are shown in Table 1-1.

Comparative Example 1 A recording medium was obtained in the same manner as in Example 1 except that the sensitizer for laser was not added to the white ink for gravure printing, and the results of laser irradiation as in Example 1 are shown in Table 1-2. Shown in. With the same irradiation energy density as in Example 1, the black ink layer could not be evaporated and scattered, and marking could not be performed. To evaporate and scatter the black ink layer, it was necessary to irradiate a laser beam with a higher energy density, which was insufficient.

Example 6 A recording medium was prepared in the same manner as in Example 2 except that the OP varnish of the protective layer was removed, and laser light was irradiated in the same manner as in Example 2. As a result, the same energy as in Example 2 was obtained. The black ink layer evaporates and scatters depending on the density, and printing with high visibility was obtained (Table 1-
1).

Example 7 A recording medium was prepared in the same manner as in Example 4 except that the black ink A was used in place of the black ink A, and the recording medium was irradiated with laser light in the same manner as in Example 4. The black ink layer was evaporated and scattered at a lower energy density than that of Example 4, and highly visible printing was obtained (Table 1-1).

Example 8 In the recording medium of Example 7, a clear ink in which an ink containing no laser sensitizer was used in white ink and a laser sensitizer was dispersed between white ink and black ink was used. A printed recording material was prepared and irradiated with laser light. As a result, 0.48Joule /
The black ink layer was evaporated and scattered at a low energy density of cm ² , and highly visible printing was obtained (Table 1-2).

Example 9 A recording medium was obtained in the same manner as in Example 7 except that coated paper was used instead of aluminum vapor-deposited paper. As a result of irradiating this recording medium with a laser beam, the black ink layer was evaporated and scattered at a low energy density of 0.53 Joule / cm ² , and high visibility printing was obtained (Table 1-2).

Comparative Example 2 A recording medium was prepared in the same manner as in Example 6 except that the white ink containing no laser sensitizer was used, and laser irradiation was carried out. With the same irradiation energy density as in Example 6, the black ink layer could not be evaporated and scattered, and marking could not be performed. To evaporate and scatter the black ink layer, it was necessary to irradiate a laser beam with a higher energy density, which was insufficient.

Comparative Example 3 A recording medium was prepared in the same manner as in Example 9 except that the white ink containing no laser sensitizer was used, and laser irradiation was carried out. With the same irradiation energy density as in Example 9, the black ink layer could not be evaporated and scattered, and marking could not be performed. To evaporate and scatter the black ink layer, it was necessary to irradiate a laser beam with a higher energy density, which was insufficient.

Comparative Example 4 A recording material was prepared by gravure-printing a white ink A containing no laser sensitizer, a black ink C containing a laser sensitizer, and an OP varnish on aluminum vapor-deposited paper in this order to obtain a recording medium. Laser irradiation was performed in the same manner as in No. 1, but the irradiation energy density was 0.65 Joul.
Even e / cm ² could not be evaporated / scattered and could not be marked. To evaporate and scatter the black ink layer, it is necessary to irradiate a laser beam with a higher energy density,
It was insufficient. The results of Comparative Examples 2 to 4 are shown in Table 1-2.
Shown in

Table 1-1

[0055]

[Table 1]

Table 1-2

[0057]

[Table 2]

[0058]

According to the display body for laser marking of the present invention, the colored layer can be destroyed by the low energy laser light, and laser marking can be performed in a wide range at a time. Since many records or displays are possible, it is particularly suitable for on-line marking of labels, nameplates, cards, containers, etc. that require printing of product names, lot numbers, codes, expiration dates, etc.

Claims (14)

[Claims] 1. A recording body having a colored layer on a support, wherein a sensitizing layer containing a laser sensitizer is formed between the support and the colored layer, and the colored layer is sensitized with laser light. A recording body for laser marking, characterized in that it is formed into a thin layer or toned so as not to prevent the layer from reaching the layer, and is destroyed or etched by heat. 2. The content of the sensitizer in the sensitizing layer is from 5 to 5.
The recording material according to claim 1, which is 90% by weight. 3. The recording material according to claim 1, wherein the recording material is a display label. 4. The laser sensitizer is one or more of inorganic metal borate salts and inorganic metal silicate salts.
Or the recording material according to item 3. 5. The laser sensitizer is one or more of synthetic mica, cordierite and kaolin.
The recording body according to any one of 1. 6. The recording material according to claim 1, wherein the color layer has a film thickness of 0.1 to 10 μm. 7. The sensitizing layer and / or the support have a color contrast with the colored layer.
The recording body according to any one of 1. 8. The recording material according to claim 1, wherein an overcoat layer for protecting the colored layer is formed on the colored layer. 9. The recording medium according to claim 8, wherein the overcoat layer is destroyed together with the colored layer by laser light during marking. 10. A laser beam for marking characters and / or graphics on a recording medium having a colored layer on a support,
In a laser marking method in which a colored layer is destroyed by heat and etched to perform marking, the recording medium has a sensitizing layer containing a laser sensitizer formed between a support and the colored layer, and the colored layer is A laser marking method characterized in that the recording material is formed into a thin layer or toned so as not to prevent the laser light from reaching the sensitizing layer. 11. The recording medium is a display label.
0. The method of claim 0. 12. A laser sensitizer is an inorganic boric acid metal salt,
11. Any one or more of inorganic metal silicates.
Or the method described in 11. 13. The laser sensitizer is one or more of synthetic mica, cordierite and kaolin.
The method according to 0, 11 or 12. 14. The overcoat layer for protecting the coloring layer is formed on the coloring layer, and the overcoat layer is destroyed together with the coloring layer by laser light during marking. The method described in.