JPH064027A - Code pattern label - Google Patents

Abstract

PURPOSE:To obtain invisible code patterns which can avert the laboriousness of printing the code patterns on various objects at each time, are protected from physical and chemical damages and has excellent weatherability. CONSTITUTION:This label consists of a base material 1, the code patterns 2 provided in at least a part on at least one surface of the base material 1 and a coating layer 3 provided on at least the code patterns 2. The code patterns 2 of the code pattern label include a fluorescent pigment which does not substantially possess an absorption region in a visible light region and a vehicle which allows the transmission of a part or the whole of the excited light from the fluorescent pigment and the emitted light from the fluorescent pigment. For example, ZnO:Zn is used as the fluorescent pigment and an acrylic resin of a photopolymn. curing type or electron beam curing type is exemplified as the vehicle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a label having a code pattern which is substantially invisible to the naked eye by using a fluorescent ink but which can be identified by being excited by light other than visible light such as ultraviolet rays.

[0002]

2. Description of the Related Art In recent years,
A so-called bar code system utilizing optical reading is widely used for personal identification and article identification.
For example, it is used as a data carrier of a POS system (point-of-sale system). These conventional barcodes can be visually recognized by humans.

On the other hand, a bar code system which is invisible to the naked eye has also been proposed (Japanese Patent Laid-Open No. 2-5).
8190). This publication discloses an apparatus for reading a barcode in a form in which a person cannot directly visually recognize its presence, that is, an invisible barcode. The invisible bar code is desired to be widely used by taking advantage of the fact that the invisible bar code cannot be visually recognized. For example, it has been proposed to attach a invisible bar code to a printed matter such as a stock certificate having a character like a voucher, or a ticket for transportation to prevent forgery. Alternatively, by using an invisible bar code as a code for retrieving information recorded in a CD-ROM, an LD or the like, it is possible to prevent the printed paper surface from being unsightly by being covered with a black bar code or the like.

However, although the above-mentioned publication discloses a device for reading a print code pattern such as a barcode, the code pattern itself is an idea and not disclosed to the extent that it can be sufficiently implemented.

Therefore, the present inventor has conducted various studies in order to commercialize the invisible code pattern. As a result, it was found that there are the following problems.

(1) A conventional code pattern such as a bar code is directly printed on a substrate such as a paper sheet which is an object to which the code pattern is attached. However, this method is complicated because it is necessary to print on various substrates having different materials and dimensions.

(2) When the invisible code pattern is used, since these are substantially invisible to the naked eye, there are few restrictions on the attaching position, and they can be attached to a relatively conspicuous place. However, it will be attached to a portion that is susceptible to physical or chemical damage. That is, due to abrasion with other articles, sweat of human hands, etc.,
There is a high risk that the code pattern will be partially damaged.
Further, it is expected that the number of objects to be repeatedly read is increased, and the possibility that the code pattern is damaged during the reading operation also increases.

Therefore, an object of the present invention is to provide a means for providing an invisible code pattern excellent in weather resistance, which can avoid the troublesome printing on various objects each time and is protected from physical and chemical damage. To provide.

[0009]

The present invention provides a code pattern label comprising a substrate, a code pattern provided on at least a part of at least one surface of the substrate, and a coating layer provided on at least the code pattern. Wherein the code pattern includes a fluorescent pigment that does not substantially have an absorption region in the visible light region and a vehicle that transmits a part or all of the excitation light of the fluorescent pigment and the emitted light of the fluorescent pigment. Regarding pattern labels.

In the present invention, the "invisible code pattern" means a code pattern which is substantially invisible to the naked eye. However, depending on the incident angle of light, the invisible code pattern may be visible to the naked eye due to irregularly reflected light due to the difference in refractive index due to the presence of the print pattern. Further, in the present invention, the "label" means
It means a sheet-like object attached to another article regardless of its size.

The present invention will be described below. As shown in FIG. 1, the label of the present invention basically comprises a base material 1, a code pattern 2 and a coating layer 3. Further, if necessary, as shown in FIG. 1, an adhesive layer 4 for adhering to an adherend can be provided on a part or all of the surface of the substrate 1 opposite to the surface on which the code pattern 2 is provided. . In this case, the coating layer 3 serves as a protective layer for the code pattern. Further, as shown in FIG. 2, the adhesive layer 4 may be provided on a part or all of the coating layer 3. In this case, the base 1 serves as a protective layer for the code pattern 2. If necessary, a release sheet (not shown) may be further provided on the adhesive layer 4.

The adhesive layer 4 can be formed using either a natural adhesive or a synthetic adhesive. The type of adhesive can be appropriately selected depending on the use of the label. Examples of natural adhesives include starch-based adhesives, protein-based adhesives, natural rubber-based adhesives, and asphalt-based adhesives. Examples of synthetic adhesives include organic adhesives (for example, thermoplastic adhesives, thermosetting adhesives, synthetic rubber adhesives) and inorganic adhesives (for example, sodium silicate).

The substrate 1 is preferably a transparent sheet or film in view of the advantage that the code pattern 2 is invisible. The material of the substrate 1 is not particularly limited, but examples thereof include polyethylene terephthalate (PET), polyvinyl chloride, polyethylene, polypropylene and the like.

The substrate 1 is in the visible region when the fluorescent pigment is irradiated with excitation light through the substrate 1 and the emitted light from the fluorescent pigment is extracted (when the substrate 1 serves as a protective layer). In addition to the transparency described above, it is formed of a material that transmits part or all of the excitation light of the fluorescent pigment and the light emission destination.

As the code pattern 2, a bar code can be exemplified, and the bar code may be a two-dimensional bar code other than the one-dimensional bar code.

The code pattern 2 transmits (a) a fluorescent pigment having substantially no absorption region in the visible region and (b) a part or all of the excitation light of the fluorescent pigment and the emitted light of the fluorescent pigment. Composed of vehicles.

The fluorescent pigment in the present invention is a fluorescent substance, that is, a substance which emits luminescence in a broad sense,
It includes both inorganic fluorescent pigments and organic fluorescent pigments.

As the inorganic fluorescent pigment, Ca, Ba, M
g, Zn, Cd and other oxides, sulfides, silicates, phosphates, tungstates and other crystals as the main component, M
A pigment obtained by adding a metal element such as n, Zn, Ag, Cu, Sb, or Pb or a rare earth element such as a lanthanoid as an activator and firing the mixture may be used. A preferable phosphor is ZnO: Zn, Br ₅ (PO ₄ ) ₃ Cl:
Eu, Zn ₂ GeO ₄ : Mn, Y ₂ O ₃ : Eu, Y
(P, V) O ₄ : Eu, Y ₂ O ₂ Si: Eu, Zn ₂ G
Examples include eO ₄ : Mn.

Examples of the organic fluorescent pigment include diaminostilbene disulfonic acid derivatives, imidazole derivatives, coumarin derivatives, triazole, carbazole, pyridine, naphthalic acid, imidazolone derivatives, dyes such as fluorescein and eosin, and compounds having a benzene ring such as anthracene. Can be used.

In terms of durability and weather resistance, inorganic pigments are excellent. On the other hand, since the organic pigment has good wettability of the ink vehicle, it is excellent in inkability even if it is not surface-treated. Among the above pigments, in order to improve durability, weather resistance, especially light resistance or printability, a stable oxide or oxyacid salt-based inorganic fluorescent pigment having a relatively large particle size and large brightness is used. preferable.

Further, in the present invention, it is preferable to adjust the particle diameter of the pigment in order to improve the fluorescent characteristics such as brightness and the printing characteristics of the ink. From this point of view, it is preferable to use, as the fluorescent pigment, pigment particles having an average particle size of 0.7 to 50 μm, more preferably 0.7 to 20 μm, and most preferably 1.0. It is desirable to use pigment particles in the range of .about.20 .mu.m. In general, it is expected that the smaller the particle size of the pigment is, the more the ink characteristics are improved. However, according to the knowledge of the present inventor, when the particle size is less than 0.7 μm, there is a phenomenon that the brightness of fluorescence decreases. Can be seen. Therefore, the lower limit of the particle size is set to 0.7 μm. On the other hand, if the upper limit of the particle size exceeds 50 μm, the fluidity becomes poor and it cannot be used as a printing ink.

The content of the fluorescent pigment with respect to the entire composition forming the code pattern is preferably 15 to 45% by weight, and more preferably 20 to 40% by weight in order to improve both brightness and ink characteristics. Is.

When the content of the fluorescent pigment is less than 15%, the fluorescent brightness in the ink composition state is extremely lowered, and for example, 1
At about 2%, it is about 1/10 of the brightness of the pigment itself.
Decrease to a degree.

Further, in the present invention, it is preferable to carry out a surface treatment in order to improve the properties of the pigment (hiding power, coloring power, oil absorption, durability, etc.). In particular, when an inorganic pigment is used, its surface is hydrophilic and its affinity with an oily polymer is poor. Therefore, it is preferable to perform a surface treatment to improve the affinity with the polymer. As a method,
For example, there are the following methods.

(A) Coating This serves as a surfactant. As a specific example,
For example, a dispersant for fatty acids (low molecular weight / high molecular weight), fatty acid salts and wax is used.

(B) Coupling agent This binds strongly to the pigment and also reacts with the polymer.
As a specific example, a silane compound, a titanium compound, a metal chelate compound, or the like is used.

(C) Polymerizable Monomer A low molecular weight monomer or oligomer is reacted with the pigment surface to form an irreversible layer. As a specific example, a polymerizable organic acid, a reactive oligomer, or the like is used.

In the code pattern of the present invention, the vehicle is light having a wavelength that excites the fluorescent pigment (excitation light).
And a vehicle that is transparent to both the emitted light of the fluorescent pigment. The optical characteristics required for the vehicle are
Depending on the type of fluorescent pigment used and the wavelength range of excitation and emission, in the present invention, specifically, 40
A substance having substantially no absorption in the visible light region of 0 to 800 nm, preferably 400 to 700 nm is suitable.

The resin constituting the vehicle of the present invention is generally a natural resin such as protein, rubber, cellulose, shellac, copal, starch, rosin, etc., vinyl resin, acrylic resin, styrene resin. Thermoplastic resin such as polyolefin resin, novolac type phenol resin, etc., thermosetting resin such as resol type phenol resin, urea resin, melamine resin, polyurethane resin, epoxy, unsaturated polyester, etc. Plasticizer for stabilizing the flexibility and strength of the film, solvent for viscosity adjustment, drying, further drying, viscosity, dispersibility,
Auxiliary agents such as various reaction agents are appropriately added.

In the present invention, since it is not desirable for the formed code pattern to adsorb contaminants by the solvent component, it is preferable to use a photopolymerization curable ink or electron beam curable ink which does not use a solvent. To do. The main component is an acrylic resin, and specifically, the following are commercially available acrylic monomers.

As the monofunctional acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl EO adduct acrylate, ethoxydiethylene glycol acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, caprolactone adduct of 2-hydroxyethyl acrylate, 2- Phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, nonylphenol EO adduct acrylate,
Acrylate obtained by adding caprolactone to nonylphenol EO adduct, 2-hydroxy-3-phenoxypropyl acrylate, tetrahydrofurfuryl acrylate, furofuryl alcohol caprolactone adduct acrylate, acryloylmorpholine, dicyclopentenyl acrylate, dicyclopentanyl acrylate, dicyclopentyl acrylate Pentenyloxyethyl acrylate, isobornyl acrylate, acrylate of caprolactone adduct of 4,4-dimethyl-1,3-dioxolane, acrylate of caprolactone adduct of 3-methyl-5,5-dimethyl-1,3-dioxolane, etc. Can be used.

On the other hand, as the polyfunctional acrylate, hexanediol diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, hydroxypivalic acid neopentyl glycol ester diacrylate, hydroxypivalic acid neopentyl glycol ester. Diacrylate of caprolactone adduct of
Acrylic acid adduct of diglycidyl ether of 1,6-hexanediol, diacrylate of acetal compound of hydroxypivalaldehyde and trimethylolpropane, 2,2-bis [4- (acryloyloxydiethoxy) phenyl] propane, 2,2-bis [4- (acryloyloxydiethoxy, phenyl] methane, hydrogenated bisphenol A ethylene oxide adduct diacrylate, tricyclodecane dimethanol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, Trimethylol propane propylene oxide adduct triacrylate, glycerin propylene oxide adduct triacrylate, dipentaerythritol hexaacrylate / pentaacrylate mixture, dipentaery Lower fatty acids and esters of acrylic acid Lithol, dipentaerythritol caprolactone adduct acrylate, tris (acryloyloxyethyl) isocyanurate, and 2-acryloyloxyethyl phosphate may be used.

Inks made of these resins are solvent-free and have a composition which causes a chain polymerization reaction by irradiation with electromagnetic waves or electron beams. Among them, those of the ultraviolet irradiation type have a photopolymerization initiator and If necessary, a polymerization inhibitor, a chain transfer agent, etc. are added as a sensitizer and an auxiliary.

Examples of the photopolymerization initiator include 1) direct photolysis type arylalkylketone, oxime ketone, acylphosphine oxide, etc. 2) radical polymerization type benzophenone derivative, thioxanthone derivative, etc.
3) Cationic polymerization reaction types include aryl diazonium salts, aryl iodonium salts, aryl sulfonium salts, aryl acetophenones, etc. Other than these, 4) energy transfer type, 5) light redox type, and 6) electron transfer type are used. obtain.

As for the electron beam curing type resin, the same resins as those used in the ultraviolet ray irradiation type resin described above are used, and a photopolymerization initiator is not required, and various auxiliaries can be added if necessary.

Further, the code pattern of the present invention can contain an irreversible decolorizable colorant in the composition. The decolorizable colorant in this case is a colorant that maintains a visible state in the visible light range and irreversibly changes to an invisible state by an operation for decoloring, for example, an operation such as irradiation of near infrared rays. When a code pattern is formed on an invisible ink composition containing such a decolorizable colorant,
The printed image can be visually identified, and the printing accuracy can be improved. After that, the color can be changed to the invisible state by performing the erasing operation.

As a specific example, the coexistence of an erasable colorant IR820B (manufactured by Showa Denko) represented by the following structural formula, a cyanine dye, and an organic boron ammonium salt such as tetrabutylammonium / butyltriphenylborate. There are some that absorb near-infrared light and couple with each other to become irreversibly transparent.

[0038]

[Chemical 1]

The code pattern can be attached on the substrate by a conventional method, for example, by printing or printing on a printer.

The code pattern label of the present invention has a layer 3 which covers the code pattern 2 provided on the base material 1. The coating layer 3 may cover at least the code pattern 2 so as not to contact the outside. The coating layer 3 is the code pattern 2 of the base material 1 on which the code pattern 2 is provided.
It is not always necessary to provide the surface not covered with, but it may be provided on the entire surface.

When the fluorescent pigment is irradiated with the excitation light through the coating layer 3 and the emitted light from the fluorescent pigment is extracted, the coating layer 3 is similar to the vehicle of the overcoat 2 in that It is formed of a material that transmits part or all of the emitted light. The coating layer 3 can be formed by overlamination or overcoating. The overlaminate can be formed by laminating a transparent film of polyethylene terephthalate, polyvinyl chloride, polyethylene, polypropylene or the like by a conventional method.

The overcoat can be formed by using the same resin as that used for the vehicle. Preferably, a photopolymerization-curable or electronic-curable ink containing a solvent-free acrylic monomer as a main component is used.
As the acrylic monomer, the above-mentioned ones can be similarly used. In addition to the monomer, the ink contains additives such as a polymerization initiator as described above, and these additives are also appropriately selected from those having transparency to the excitation light and the emission light of the fluorescent pigment. To be elected.

Further, by adding 0.1 to 80 parts by weight of a phosphazene-based curable resin represented by the following formula to this vehicle, high hardness, abrasion resistance and heat resistance can be imparted.

[0044]

[Chemical 2]

Further, as shown in FIG. 3, the coating layer 3 can be used as an adhesive layer by forming it with an adhesive. In this case, the base material 1 serves as a protective layer. As the adhesive for forming the coating layer 3, the same adhesive as that for forming the adhesive layer can be used.

Further, in the code pattern label of the present invention, in the embodiment shown in FIG. 1, a visible light transmitting / invisible light absorbing layer 5 can be provided on at least one surface of the substrate 1 as shown in FIG. . Similarly, in the embodiment shown in FIG. 2, a visible light transmitting / invisible light absorbing layer 5 can be provided between the coating layer 3 and the adhesive layer 4 as shown in FIG.

Originally, the transparent fluorescent code pattern should not be affected by the adherend to which the transparent fluorescent code pattern label is attached when reading the code pattern. However, in reality, since the invisible excitation light absorbency is different for each part of the adherend that becomes the background, the reading is affected except when the background is solid color, and in some cases, the code pattern is read correctly. There are things you can't do.

Therefore, visible light is transmitted in the above-described manner.
When the invisible excitation light absorbing layer 5 is formed on a label, the visible light transmitting / invisible excitation light absorbing layer 5 normally transmits visible light so that a visible printed matter or the like having a label attached thereto can be visually recognized as in the conventional case. On the other hand, when the ultraviolet light or the infrared light for reading the code pattern of the label is irradiated, the visible light transmitting / invisible light absorbing layer 5 uniformly absorbs high,
Irradiation light is cut off to the visible printed matter with a label attached. Therefore, the absorbance of the invisible light (excitation light of the fluorescent pigment) on the lower surface of the code pattern becomes uniform, and the same optical characteristics as in the case where the background is solid plain can be obtained. The visible light transmitting / invisible excitation light absorbing layer 5 can be formed by forming a known ultraviolet absorber into an ink and printing it.

Examples of the ultraviolet absorber include benzophenone type (eg, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone).
, Benzotriazole-based (for example, 2- (5-methyl-2-
Hydroxyphenyl) -benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2 H-benzotriazole, 2- (3,5-di-t-butyl-2) -Hydroxyphenyl) -5-chlorobenzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-butyl-2 -Hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole , 2- (2-hydroxy-5-t-octyl) -benzotriazole), titanium oxide, zinc oxide and the like.

[0050]

EXAMPLES The present invention will now be described in more detail with reference to examples.

Example 1 Polyethylene terephthalate (PET) sheet (thickness: 5
0 μm) was used as a substrate, and a transparent fluorescent ink having the composition shown in Table 1 below was used to print a barcode on the substrate by a conventional method. The transparent fluorescent ink and fluorescent pigment (Zn
The optical characteristics of O: Zn) are shown in FIG.

[0052]

[Table 1]

The obtained printed matter was irradiated with ultraviolet rays (200 to 3).
00 nm) to cure the ink on which the barcode was formed. Next, a PET sheet (thickness: 16μ on the barcode
m) was laminated to form a coating layer to obtain a label of the present invention. Furthermore, natural rubber latex was applied as an adhesive to one surface of this label, and release paper was attached on the adhesive layer.

Example 2 Instead of laminating a PET sheet, an ultraviolet-curable transparent ink was applied and irradiated with ultraviolet rays to be cured to form a coating layer (2
(μm) was formed and the same procedure as in Example 1 was carried out to obtain a label of the present invention.

Example 3 The label of the present invention was prepared in the same manner as in Example 1 except that a natural rubber latex was applied instead of laminating a PET sheet to form a coating layer (10 μm) having adhesiveness. Obtained.

Example 4 A PET sheet having a visible light transmitting / invisible light absorbing layer formed by coating and curing an ink containing zinc oxide as a substrate was used, and a barcode was formed on the visible light transmitting / invisible light absorbing layer. A label of the present invention was obtained in the same manner as in Example 1 except that the label was provided.

[0057]

The label of the present invention is invisible including the code pattern and can be attached without obstructing the pattern on the surface of the object. Moreover, since the code pattern is formed on the label in advance, it is possible to attach the code pattern to various objects very easily as compared with printing the code pattern on the surface of the object. Further, since the protective layer is provided on the code pattern, the weather resistance is excellent, and there is an advantage that the code pattern is not damaged and the data reading is not hindered.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a code pattern label of the present invention.

FIG. 2 is a schematic sectional view of a code pattern label of the present invention.

FIG. 3 is a schematic cross-sectional view of a code pattern label of the present invention.

FIG. 4 is a schematic sectional view of a code pattern label of the present invention.

FIG. 5 is a schematic sectional view of a code pattern label of the present invention.

FIG. 6 shows optical characteristics of transparent fluorescent ink (B) and fluorescent pigment (ZnO: Zn) (A) used in the examples.

Claims (1)

[Claims] 1. A code pattern label comprising a base material, a code pattern provided on at least a part of at least one surface of the base material, and a coating layer provided on at least the code pattern, the code pattern comprising: The above code pattern label comprising a fluorescent pigment having substantially no absorption region in the visible light region and a vehicle that transmits part or all of the excitation light of the fluorescent pigment and the emitted light of the fluorescent pigment.